Note: Descriptions are shown in the official language in which they were submitted.
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CIRCUIT INTERRUPTER WITH SPACE
CONSERVING BASE/COVER ATTACHMENT
CROSS REFERENCE TO RELATED APPLICATIONS
The subject matter of this invention is related to concurrently filed, co-
pending applications: U.S. Patent Application Serial No. / , Eaton
Docket No. 97-PDC-317, filed , 1999, entitled "Insulator For A Lug
Assembly Accessory Of A Circuit Interrupter", issued ; U.S.
Patent Application Serial No. / , Eaton Docket No. 98-PDC-182,
filed , 1999, entitled "Circuit Interrupter With Improved Welded
Contact Interlock", issued ; U.S. Patent Application Serial No.
/ , Eaton Docket No. 98-PDC-273, filed , 1999, entitled
"Circuit Interrupter With Space-Conserving Handle Mechanism", issued
U.S. Patent Application Serial No. / , Eaton Docket
No. 98-PDC-277, filed , 1999, entitled "Circuit Interrupter With
Housing Support", issued ; U.S. Patent Application Serial No.
/ , Eaton Docket No. 98-PDC-279, filed , 1999, entitled
"Circuit Interrupter With Base/Cover Attachment Enabling Venting", issued
U.S. Patent Application Serial No. / , Eaton Docket
No. 98-PDC-295, filed , 1999, entitled "Circuit Interrupter With
Improved Push-To-Trip Actuator", issued ; U.S. Patent Application
Serial No. / , Eaton Docket No. 98-PDC-342, filed ,
1999, entitled "Circuit Interrupter With An Improved Electrical Terminal For
Attachment To A Connecting Device", issued ; U.S. Patent
Application Serial No. / , Eaton Docket No. 98-PDC-344, filed
1999, entitled "Circuit Interrupter With An Improved Magnetically-
Induced Automatic Trip Assembly", issued ; U.S. Patent
Application Serial No. / , Eaton Docket No. 98-PDC-345, filed
1999, entitled "Circuit Interrupter With An Improved Magnetically-
Induced Trip Mechanism", issued ; U.S. Patent Application Serial
CA 02316744 2000-08-24
3 98-PDC-278
No. / , Eaton Docket No. 98-PDC-348, filed , 1999,
entitled "Circuit Interrupter With An Improved Magnetically-Induced Automatic
Trip Assembly", issued ; U.S. Patent Application Serial No.
/ , Eaton Docket No. 98-PDC-560, filed , 1999, entitled
"Circuit Interrupter With An Operating Mechanism Having Improved Support",
issued ; U.S. Patent Application Serial No. / , Eaton
Docket No. 99-PDC-040, filed , 1999, entitled "Circuit Interrupter
Including An Insulation Barrier For A Connecting Device", issued ;
U.S. Patent Application Serial No. / , Eaton Docket No. 99-PDC-
092, filed , 1999, entitled "Circuit Interrupter With Improved Handle
Interconnection", issued ; U.S. Patent Application Serial No.
/ , Eaton Docket No. 99-PDC-135, filed , 1999, entitled
"Circuit Interrupter With Cradle Having An Improved Pivot Pin Connection",
issued ; U.S. Patent Application Serial No. / , Eaton
Docket No. 99-PDC-276, filed , 1999, entitled "Circuit Interrupter
With A Trip Mechanism Having An Improved Latch Connection", issued
U.S. Patent Application Serial No. / , Eaton Docket
No. 99-PDC-277, filed , 1999, entitled "Circuit Interrupter With A Trip
Mechanism Having A Biased Latch", issued ; U.S. Patent
Application Serial No. / , Eaton Docket No. 99-PDC-279, filed
1999, entitled "Circuit Interrupter With A Trip Mechanism Having
Improved Spring Biasing", issued ; U.S. Patent Application Serial
No. / , Eaton Docket No. 99-PDC-280, filed , 1999,
entitled "Circuit Interrupter Providing Improved Securement Of An Electrical
Terminal Within The Housing", issued ; U.S. Patent Application
Serial No. / , Eaton Docket No. 99-PDC-321, filed ,
1999, entitled "Circuit Interrupter With A Magnetically-Induced Automatic Trip
Assembly Having Improved Interconnection", issued ; U.S. Patent
Application Serial No. / , Eaton Docket No. 99-PDC-322, filed
, 1999, entitled "Circuit Interrupter With An Automatic Trip Assembly
Having An Improved BiMetal Configuration", issued ; and U.S.
Patent Application Serial No. / , Eaton Docket No. 99-PDC-323,
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4 98-PDC-278
filed , 1999, entitled "Circuit Interrupter With An Automatic Trip
Assembly Configured For Reducing Blowoff Force", issued
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to circuit interrupters generally and, more
specifically, to those kinds of circuit interrupters having a housing with a
cover
securable to a base.
DESCRIPTION OF THE PRIOR ART
Molded case circuit breakers and interrupters are well known in the art as
exemplified by U.S. Patent No. 4,503,408 issued March 5, 1985, to Mrenna et
al., and U.S. Patent 5,910,760 issued June 8, 1999 to Malingowski et al., each
of which is assigned to the assignee of the present application and
incorporated
herein by reference.
A continuing industry objective with respect to many types of circuit
interrupters is to be able to reduce the size and/or footprint of the
interrupter
housing while at the same time providing the same or improved performance
capabilities. A major advantage of creating such a "smaller package" is that
it
provides increased flexibility in installation. However, a consequence of this
objective is that the internal space constraints of such interrupters have
become
much more limiting, posing certain design obstacles that need to be overcome.
The housing of circuit interrupters typically includes a base on which is
positioned a cover. An attaching device, such as a screw, is used to secure
the
cover to the base. Such an attaching device usually enters an opening in the
cover and extends through and enters a corresponding opening in the base.
The attaching device must penetrate a sufficient distance into the base so
that
the attachment has enough strength to maintain the connection of the cover to
the base during all foreseeable operational conditions of the interrupter.
The prior art provides for such attachment by having the attaching device
penetrate a significant distance into the body of the base. In larger
interrupters
that do not have the aforementioned space constraints, this penetration is not
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98-PDC-278
a major problem since there is no shortage of internal housing space. However,
in the smaller interrupters having the aforementioned space constraints, this
penetration undesirably occupies a significant portion of the otherwise usable
internal space of the interrupter.
5 It would be advantageous if a way existed by which the cover could be
effectively and conveniently secured to the base without occupying a
significant
portion of the usable internal space of the interrupter.
SUMMARY OF THE INVENTION
The present invention provides a circuit interrupter that meets all of the
above-identified needs.
In accordance with the present invention, a circuit interrupter is provided
which includes separable main contacts, an operating mechanism
interconnected with the separable main contacts, and a housing in which the
separable main contacts and the operating mechanism are disposed. The
housing includes a base having a top region, with the top region having a
raised
portion. The housing further includes a cover having a bottom region, with the
bottom region having a cut-away portion that mates with the raised portion of
the
base. Also provided is an attaching device that secures the cover to the base.
The attaching device is inserted through a first aperture in the cut-away
portion
and into a second aperture in the raised portion.
This and other objects and advantages of the present invention will
become apparent from a reading of the following description of the preferred
embodiment taken in connection with the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an orthogonal view of a molded case circuit breaker
embodying the present invention.
Figure 2 is an exploded view of the base and cover of the circuit
interrupter of Figure 1.
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Figure 3 is side elevational view of an internal portion of the circuit
interrupter of Figure 1.
Figure 4 is an orthogonal view of the internal portions of the circuit
interrupter of Figure 1 without the base and cover.
Figure 5 is an orthogonal view of an internal portion of the circuit
interrupter of Figure 1 including the operating mechanism.
Figure 6 is a side elevational, partially broken away view of the operating
mechanism of the circuit interrupter of Figure 1 with the contacts and the
handle
in the OFF disposition.
Figure 7 is a side elevational, partially broken away view of the operating
mechanism with the contacts and the handle in the ON disposition.
Figure 8 is a side elevational, partially broken away view of the operating
mechanism with the contacts and the handle in the TRIPPED disposition.
Figure 9 is a side elevational, partially broken away view of the operating
mechanism during a resetting operation.
Figure 10A is an orthogonal view of the trip bar assembly of the trip
mechanism of the circuit interrupter of Figure 1.
Figure 10B is another orthogonal view of the trip bar assembly of Figure
1 OA.
Figure 10C is another orthogonal view of the trip bar assembly of Figure
10A showing the groove therein.
Figure 10D is an orthogonal view of the torsion spring of the trip bar
assembly shown in Figure 10A.
Figure 10E is an orthogonal view the trip bar assembly of Figure 10A with
the spring of Figure 10D attached.
Figure 1 OF is another orthogonal view of the trip bar assembly and spring
of Figure 10E.
Figure 11 is an orthogonal view of a latch used in connection with the trip
mechanism of the circuit interrupter of Figure 1.
Figure 12 is an orthogonal view of the sideplate assembly, cradle, latch,
and trip bar assembly of an internal portion of the circuit interrupter of
Figure 1.
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Figure 13 is an exploded view of the internal portion of the circuit
interrupter shown in Figure 12.
Figure 14 is an orthogonal, partially broken away view of the engagement
between the latch and the trip bar assembly of the circuit interrupter of
Figure 1.
Figure 15 is an orthogonal, partially broken away view of the base and an
internal portion of the circuit interrupter including the push-to-trip
actuator of the
trip mechanism.
Figure 16A is an orthogonal view of the push-to-trip actuator shown in
Figure 15.
Figure 16B is another orthogonal view of the push-to-trip actuator shown
in Figure 15.
Figure 17 is an orthogonal view of the button of the push-to-trip actuator
shown in Figure 15.
Figure 18A is an orthogonal view of the automatic trip assembly of the trip
mechanism of the circuit interrupter of Figure 1.
Figure 18B is another orthogonal view of the automatic trip assembly
shown in Figure 18A.
Figure 18C is an orthogonal view of the automatic trip assembly shown
in Figure 18A showing the initial positioning step of its armature.
Figure 19A is an orthogonal view of the magnetic yoke of the automatic
trip assembly shown in Figure 18A.
Figure 19B is another orthogonal view of the magnetic yoke of the
automatic trip assembly shown in Figure 18A.
Figure 20 is an orthogonal view of the bimetal of the automatic trip
assembly shown in Figure 18A.
Figure 21 is an orthogonal view of the armature of the automatic trip
assembly shown in Figure 18A.
Figure 22A is an orthogonal view of the load terminal of the automatic trip
assembly shown in Figure 18A.
Figure 22B is another orthogonal view of the load terminal of the
automatic trip assembly shown in Figure 18A.
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Figure 23 is an orthogonal, partially broken away view of the base of the
circuit interrupter of Figure 1 showing the grooves in which the load terminal
of
the automatic trip assembly is inserted.
Figure 24 is an orthogonal, partially broken away view similar to Figure 23
showing the base with the load terminal inserted.
Figure 25 is a side elevational view of the base of the circuit interrupter
of Figure 1 showing the tapered sides thereof.
Figure 26 is an orthogonal, partially broken away view of the cover of the
circuit interrupter of Figure 1 showing an abutment wall that contacts the
inserted
load terminal of Figure 24.
Figure 27 is another orthogonal view of the cover and abutment wall
shown in Figure 26.
Figure 28A is an orthogonal view of another embodiment of the load
terminal that may be implemented in the automatic trip assembly of the trip
mechanism of the circuit interrupter.
Figure 28B is another orthogonal view of the alternative embodiment of
the load terminal shown in Figure 28A.
Figure 28C is another orthogonal view of the alternative embodiment of
the load terminal showing the underside of the connector portion.
Figure 29 is an orthogonal view of the self-retaining collar used in
connection with the line and load terminals of the circuit interrupter of
Figure 1.
Figure 30A is a side elevational view of the cradle of the operating
mechanism of the circuit interrupter.
Figure 30B is an orthogonal view of the cradle pivot pin of the operating
mechanism of the circuit interrupter shown in Figure 1.
Figure 31 is an orthogonal view of the handle assembly of the operating
mechanism of the circuit interrupter shown in Figure 1.
Figure 32 is an orthogonal view of the cam housing of the crossbar
assembly of the operating mechanism.
Figure 33 is a side elevational, partially broken away view of an internal
portion of the circuit interrupter showing the handle assembly, sideplate
assembly, and crossbar assembly with associated stop members.
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Figure 34A is an orthogonal view of the handle of the operating
mechanism of the circuit interrupter shown in Figure 1.
Figure 34B is a side elevational view of the handle of Figure 34A.
Figure 34C is another orthogonal view of the handle of Figure 34A.
Figure 34D is an underneath view of the handle of Figure 34A.
Figure 35 is an orthogonal view of the handle slider of the operating
mechanism of the circuit interrupter shown in Figure 1.
Figure 36 is an exploded, partially broken away view of the cover, handle,
and handle slider of the circuit interrupter of Figure 1.
Figure 37 is an orthogonal, partially broken away view similar to Figure 36
showing the engagement of the handle with the handle slider and the cover.
Figure 38 is another orthogonal view of the handle of Figure 34A showing
the grooves for the handle slider.
Figure 39 is an exploded, profile view of the base and the cover of the
circuit interrupter of Figure 1.
Figure 40 is a cross-sectional view of the cover secured to the base,
taken along the line 40-40 of Figure 1.
Figure 41 is an orthogonal view of the attaching device used to secure the
cover to the base.
Figure 42 is an exploded view of the cover and the base of the circuit
interrupter of Figure 1 and the support members thereof.
Figure 43 is an overhead view of the base showing the slots and grooves
therein associated with the support members shown in Figure 42.
Figure 44A is an orthogonal view of one of the support members shown
in Figure 42.
Figure 44B is an overhead view of the support member shown in Figure
44A.
Figure 45A is an orthogonal view of the other support member shown in
Figure 42.
Figure 45B is another orthogonal view of the support member shown in
Figure 45A.
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98-PDC-278
Figure 45C is an overhead view of the support member shown in Figure
45A.
Figure 46 is an orthogonal view of the base and internal portions of the
circuit interrupter of Figure 1 showing the positioning of the support
members.
5 Figure 47A is an orthogonal view of the deflector used in connection with
the self-retaining collar of the line terminal of the circuit interrupter of
Figure 1.
Figure 47B is another orthogonal view of the deflector shown in Figure
47A.
Figure 48 is an orthogonal view of the internal portions of the circuit
10 interrupter of Figure 1 without the arc extinguisher assembly.
Figure 49 is another orthogonal view similar to Figure 48 but also showing
the positioning of the deflector.
Figure 50 is an exploded view of the base and cover of the circuit
interrupter of Figure 1 again showing the positioning of the deflector.
Figure 51 is an orthogonal view of a lug assembly that may be
implemented with the circuit interrupter of Figure 1 and the lug insulator
associated therewith.
Figure 52 is an orthogonal view of the lug insulator shown in Figure 51.
Figure 53 is an orthogonal view of the lug assembly and lug insulator of
Figure 51 in an assembled state.
Figure 54 is an orthogonal view of the circuit interrupter of Figure 1 with
the lug assembly and lug insulator attached.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings and Figures 1 and 2 in particular, shown
is a molded case circuit breaker 10. Circuit breaker 10 includes a base 12
mechanically interconnected with a cover 14 to form a circuit breaker housing
15. Holes or openings 16 (Figure 2) are provided in cover 14 for accepting
screws or other attaching devices 128 that enter corresponding holes or
openings 18 in base 12 for fastening cover 14 to base 12. Holes 20, which
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1 1 98-PDC-278
feed through cover 14, are provided for internal access to circuit breaker 10,
as described in greater detail below. At the interface between base 12 and
cover 14 are small openings 21 for venting purposes, as described in greater
detail below. Cover 14 includes a handle opening 22 through which protrudes
a handle 24 (Figure 1 ) that is used in a conventional manner to manually
open and close the contacts of circuit breaker 10 and to reset circuit breaker
when it is in a tripped state. Handle 24 may also provide an indication of
the status of circuit breaker 10 whereby the position of handle 24 corresponds
with a legend (not shown) on cover 14 near handle opening 22 which clearly
10 indicates whether circuit breaker 10 is ON (contacts closed), OFF (contacts
open), or TRIPPED (contacts open due to, for example, an overcurrent
condition). Cover 14 also includes a rectangular opening 23 (Figure 2)
through which protrudes a top portion 25A of a button for a push-to-trip
actuator, the details of which are described below. Also shown is a load
conductor opening 26 in base 12 that shields and protects a load terminal
(not shown). Although circuit breaker 10 is depicted as a single-phase circuit
breaker, the present invention is not limited to single-phase operation.
Referring now to Figure 3, a longitudinal section of a side elevation,
partially broken away and partially in phantom, of circuit breaker 10 is shown
having a load terminal 28 and a line terminal 29. There is shown a plasma
arc acceleration chamber 30 comprising a slot motor assembly 32 and an arc
extinguisher assembly 34. Also shown is a contact assembly 36, an
operating mechanism 38, and a trip mechanism 40.
Referring again to Figure 3, and now also to Figure 4 which shows a
side elevational view of the internal workings of circuit breaker 10 without
base 12 and cover 14, slot motor assembly 32 is shown as including a
separate upper slot motor assembly 32A and a separate lower slot motor
assembly 32B. Upper slot motor assembly 32A includes an upper slot motor
assembly housing 41 within which are stacked side-by-side U-shaped upper
slot motor assembly plates 42. Similarly, lower slot motor assembly 32B
includes a lower slot motor assembly housing 43 within which are stacked
side-by-side lower slot motor assembly plates 44. Plates 42 and 44 are both
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composed of magnetic material.
Arc extinguisher assembly 34 includes an arc chute 46 within which
are positioned spaced-apart generally parallel angularly offset arc chute
plates 48 and an upper arc runner 48A. As known to one of ordinary skill in
the art, the function of arc extinguisher assembly 34 is to receive and
dissipate electrical arcs that are created upon separation of the contacts of
the circuit breaker.
Referring now to Figure 5, shown is an orthogonal view of an internal
portion of circuit breaker 10. There is shown contact assembly 36 comprising
a movable contact arm 50 supporting thereon a movable contact 52, and a
stationary contact arm 54 supporting thereon a stationary contact 56.
Stationary contact arm 54 is electrically connected to line terminal 29 and,
as
discussed below, movable contact arm 50 is electrically connected to load
terminal 28. Also shown is a crossbar assembly 60 which traverses the width
of circuit breaker 10 and is rotatably disposed on an internal portion of base
12 (not shown). Actuation of operating mechanism 38, in a manner described
in detail below, causes crossbar assembly 60 and movable contact arm 50 to
rotate into or out of a disposition which places movable contact 52 into or
out
of a disposition of electrical continuity with fixed contact 56. Crossbar
assembly 60 includes a movable contact cam housing 62 in which is disposed
a pivot pin 64 upon which movable contact arm 50 is rotatably disposed.
Under normal circumstances, movable contact arm 50 rotates in unison with
the rotation of housing 62 as housing 62 is rotated clockwise or counter-
clockwise by action of operating mechanism 38. However, it is to be noted
that movable contact arm 50 is free to rotate (within limits) independently of
the rotation of crossbar assembly 60. In particular, in certain dynamic,
electro-magnetic situations, movable contact arm 50 can rotate upwardly
about pivot pin 64 under the influence of high magnetic forces. This is
referred to as "blow-open" operation, and is described in greater detail
below.
Continuing to refer to Figure 5 and again to Figure 3, operating
mechanism 38 is shown. Operating mechanism 38 is structurally and
functionally similar to that shown and described in United States Patent No.
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13 98-PDC-278
4,503,408 issued March 5, 1985 to Mrenna et al, and United States Patent
5,910,760 issued June 8, 1999, both disclosures of which are incorporated
herein by reference. Operating mechanism 38 comprises a handle arm or
handle assembly 70 (connected to handle 24), a configured plate or cradle
72, an upper toggle link 74, an interlinked lower toggle link 76, and an upper
toggle link pivot pin 78 which interlinks upper toggle link 74 with cradle 72.
Lower toggle link 76 is pivotally interconnected with upper toggle link 74 by
way of an intermediate toggle link pivot pin 80, and with crossbar assembly
60 at pivot pin 64. Provided is a cradle pivot pin 82 which is laterally and
rotatably disposed between parallel, spaced apart operating mechanism
support members or sideplates 84. Cradle 72 is free to rotate (within limits)
via cradle pivot pin 82. Also provided is a handle assembly roller 86 which is
disposed in and supported by handle assembly 70 in such a manner as to
make mechanical contact with (roll against) arcuate portions of a back region
87 of cradle 72 during a "resetting" operation of circuit breaker 10 as is
described below. A main stop bar 88 is laterally disposed between sideplates
84, and provides a limit to the counter-clockwise movement of cradle 72.
Referring now to Figure 6, an elevation of that part of circuit breaker 10
particular associated with operating mechanism 38 is shown for the OFF
disposition of circuit breaker 10. Contacts 52 and 56 are shown in the
disconnected or open disposition. An intermediate latch 90 is shown in its
latched position wherein it abuts hard against a lower portion 92 of a latch
cutout region 94 of cradle 72. A pair of side-by-side aligned compression
springs (not shown) such as shown in United States Patent No. 4,503,408 is
disposed between the top portion of handle assembly 70 and the intermediate
toggle link pivot pin 80. The tension in these springs has a tendency to load
lower portion 92 of cradle 72 against the intermediate latch 90. In the OPEN
disposition shown in Figure 6, latch 90 is prevented from unlatching cradle
72,
notwithstanding the spring tension, because the other end thereof is fixed in
place by a rotatable trip bar assembly 190 of trip mechanism 40. As is
described in more detail below, trip bar assembly 190 is spring-biased in the
counter-clockwise rotational direction against the intermediate latch 90. This
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is the standard latch arrangement found in all dispositions of circuit breaker
except the TRIPPED disposition which is described below.
Referring now to Figure 7, operating mechanism 38 is shown for the
ON disposition of circuit breaker 10. In this disposition, contacts 52 and 56
5 are closed (in contact with each other) whereby electrical current may flow
from load terminal 28 to line terminal 29. In order to achieve the ON
disposition, handle 24, and thus fixedly attached handle assembly 70, are
rotated in a counter-clockwise direction (to the left) thus causing the
intermediate toggle link pivot pin 80 to be influenced by the tension springs
10 (not shown) attached thereto and to the top of handle assembly 70. The
influence of the tension springs causes upper toggle link 74 and lower toggle
link 76 to assume the position shown in Figure 7 which causes the pivotal
interconnection with crossbar assembly 60 at pivot point 64 to rotate crossbar
assembly 60 in the counter-clockwise direction. This rotation of crossbar
assembly 60 causes movable contact arm 50 to rotate in the counter-
clockwise direction and ultimately force movable contact 52 into a pressurized
abutted disposition with stationary contact 56. It is to be noted that cradle
72
remains latched by intermediate latch 90 as influenced by trip mechanism 40.
Referring now to Figure 8, operating mechanism 38 is shown for the
TRIPPED disposition of circuit breaker 10. The TRIPPED disposition is
related (except when a manual tripping operation is performed, as described
below) to an automatic opening of circuit breaker 10 caused by the thermally
or magnetically induced reaction of trip mechanism 40 to the magnitude of the
current flowing between load conductor 28 and line conductor 29. The
operation of trip mechanism 40 is described in detail below. For purposes
here, circumstances such as a load current with a magnitude exceeding a
predetermined threshold will cause trip mechanism 40 to rotate trip bar
assembly 190 clockwise (overcoming the spring force biasing assembly 190
in the opposite direction) and away from intermediate latch 90. This
unlocking of latch 90 releases cradle 72 (which had been held in place at
lower portion 92 of latch cutout region 94) and enables it to be rotated
counter-clockwise under the influence of the tension springs (not shown)
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interacting between the top of handle assembly 70 and the intermediate
toggle link pivot pin 80. The resulting collapse of the toggle arrangement
causes pivot pin 64 to be rotated clockwise and upwardly to thus cause
crossbar assembly 60 to similarly rotate. This rotation of crossbar assembly
60 causes a clockwise motion of movable contact arm 50, resulting in a
separation of contacts 52 and 56. The above sequence of events results in
handle 24 being placed into an intermediate disposition between its OFF
disposition (as shown in Figure 6) and its ON disposition (as shown in Figure
7). Once in this TRIPPED disposition, circuit breaker 10 can not again
achieve the ON disposition (contacts 52 and 56 closed) until it is first
"reset"
via a resetting operation which is described in detail below.
Referring now to Figure 9, operating mechanism 38 is shown during
the resetting operation of circuit breaker 10. This occurs while contacts 52
and 56 remain open, and is exemplified by a forceful movement of handle 24
to the right (or in a clockwise direction) after a tripping operation has
occurred
as described above with respect to Figure 8. As handle 24 is thus moved,
handle assembly 70 moves correspondingly, causing handle assembly roller
86 to make contact with back region 87 of cradle 72. This contact forces
cradle 72 to rotate clockwise about cradle pivot pin 82 and against the
tension
of the springs (not shown) that are located between the top of handle
assembly 70 and the intermediate toggle link pivot pin 80, until an upper
portion 93 of latch cutout region 94 abuts against the upper arm or end of
intermediate latch 90. This abutment forces intermediate latch 90 to rotate to
the left (or in a counter-clockwise direction) so that the bottom portion
thereof
rotates to a disposition of interlatching with trip bar assembly 190, in a
manner described in more detail below. Then, when the force against handle
24 is released, handle 24 rotates to the left over a small angular increment,
causing lower portion 92 of latch cutout region 94 to forcefully abut against
intermediate latch 90 which is now abutted at its lower end against trip bar
assembly 190. Circuit breaker 10 is then in the OFF disposition shown in
Figure 6, and handle 24 may then be moved counter-clockwise (to the left)
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towards the ON disposition depicted in Figure 7 (without the latching
arrangement being disturbed) until contacts 52 and 56 are in a disposition of
forceful electrical contact with each other. However, if an overcurrent
condition still exists, a tripping operation such as depicted and described
above with respect to Figure 8 may again take place causing contacts 52 and
56 to again open.
Referring again to Figures 3, 4, and 5, upper slot motor assembly 32A
and lower slot motor assembly 32B are structurally and functionally similar to
that described in United States Patent 5,910,760 and plates 42 and 44
thereof form an essentially closed electro-magnetic path in the viscinity of
contacts 52 and 56. At the beginning of a contact opening operation,
electrical current continues to flow in movable contact arm 50 and through an
electrical arc created between contacts 52 and 56. This current induces a
magnetic field into the closed magnetic loop provided by upper plates 42 and
lower plates 44 of upper slot motor assembly 32A and lower slot motor
assembly 32B, respectively. This magnetic field electromagnetically interacts
with the current in such a manner as to accelerate the movement of movable
contact arm 50 in the opening direction whereby contacts 52 and 56 are more
rapidly separated. The higher the magnitude of the electrical current flowing
in the arc, the stronger the magnetic interaction and the more quickly
contacts
52 and 56 separate. For very high current (an overcurrent condition), the
above process provides the blow-open operation described above in which
movable contact arm 50 forcefully rotates upwardly about pivot pin 64 and
separates contacts 52 and 56, this rotation being independent of crossbar
assembly 60. This blow-open operation is shown and described in United
States Patent No. 3,815,059 issued June 4, 1974, to Spoelman and
incorporated herein by reference, and provides a faster separation of contacts
52 and 56 than can normally occur as the result of a tripping operation
generated by trip mechanism 40 as described above in connection with
Figure 8.
In connection with the above-described blow-open operation, crossbar
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assembly 60 and, in particular, cam housing 62 are structurally and
functionally similar to that described in United States 5,910,760. In
particular,
cam housing 62 includes a spring-loaded cam follower (not shown) which,
when a blow-open opeation has occurred, latches movable contact arm 50 in
its blown-open disposition.
Referring now to Figures 10A, 10B, 10C, 10D, 10E, and 10F, shown is
integrally molded trip bar assembly 190 of trip mechanism 40. Assembly 190
includes a trip shaft 192 to which is connected a thermal trip bar or paddle
194, a magnetic trip bar or paddle 196, and a manual trip bar 198, the
function of each of which is described in detail below. Assembly 190 also
includes an intermediate latch interface 200 having a protrusion or stepped-
up region 201 and a cutout region or stepped-down region 203 with a surface
203A. Near one end of trip shaft 192 is a channel or groove 199 that partially
extends around the circumference thereof. As shown in Figure 10C, groove
199 has an end 199A on the underside of trip shaft 192 that defines a cavity
extending into shaft 192. Assembly 190 also includes a torsion spring 202, as
shown in Figure 10D, having an elbow 202A defining an end 202B, and an
end 202C. As shown in Figures 10E and 10F, spring 202 is wound around
the end of trip shaft 192, and is partially seated within groove 199. Elbow
202A of spring 202 is shown positioned at end 199A of groove 199, with end
202B of spring 202 inserted into the cavity. Groove 199 serves to properly
position spring 202 and prevent dislodgment thereof from shaft 192. In a
preferred embodiment wherein spring 202 is approximately .018 inches in
diameter, groove 199 is approximately .030 inches in width and approximately
.015 inches deep.
Referring now to Figure 11, shown is intermediate latch 90. Latch 90
includes a main member 206 having ends 207 which are bent towards each
other and in which are formed holes or openings 208. Extending from main
member 206 is an upper latch portion 210 and a lower latch portion 212, the
latch portions being linearly offset from each other in the exemplary
embodiment. Lower latch portion 212 includes a protruding region 213 with a
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bottom surface 213A, and a cutout region 214.
Referring now also to Figures 12, 13, and 14, shown is trip bar
assembly 190 in conjunction with a portion of the internal workings of circuit
breaker 10. Trip shaft 192 is shown laterally disposed between parallel
sideplates 84 of the sideplate assembly, with its ends positioned within holes
or openings 216. This disposition provides a pivot area about which trip bar
assembly 190 can rotate. This rotation is influenced by spring 202 that
rotationally biases assembly 190 in the counter-clockwise direction. Also
shown is intermediate latch 90 which, like trip shaft 192, is laterally
disposed
between sideplates 84. Holes or openings 208 of latch 90 are mated with
corresponding circular protrusions or indents 218 in sideplates 84, providing
a
pivot area for rotation of latch 90. Protrusions or indents 220 in sideplates
84
provide a stop for limiting the rotation of latch 90 in the clockwise
direction
which occurs during a tripping operation as described below.
Figure 12 shows the latching arrangement found in all dispositions of
circuit breaker 10 except the TRIPPED disposition. Lower latch portion 212
of latch 90 is shown fixed in place by intermediate latch interface 200 of
trip
bar assembly 190. In particular, as also seen in Figure 14, cutout region 214
of latch 90 is shown mated with protrusion 201 of interface 200, with bottom
surface 213A of protruding region 213 of latch 90 in an abutted, engaged
relationship with surface 203A of interface 200. Upper latch portion 210 of
latch 90 is shown abutted hard against lower portion 92 of latch cutout region
94 of cradle 72. Because latch 90 is prevented from clockwise rotation due to
the engagement of lower latch portion 212 with intermediate latch interface
200, the abutment of upper latch portion 210 with cradle 72 prevents the
counter-clockwise rotation of cradle 72, notwithstanding the spring tension
(described above) experienced by the cradle in that direction. However,
during a tripping operation as described below, trip bar assembly 190 is
rotated clockwise (overcoming the spring tension provided by spring 202),
causing surface 203A of intermediate latch interface 200 to rotate away from
its abutted, engaged relationship with protruding region 213 of intermediate
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latch 90. This disengagement enables the spring forces experienced by
cradle 72 to rotate latch 90 in a clockwise direction, thereby terminating the
hard abutment between upper latch portion 210 and cradle 72, and releasing
the cradle to be rotated counter-clockwise by the aforementioned springs until
operating mechanism 38 is in the TRIPPED disposition described above in
connection with Figure 8.
In the preferred exemplary embodiment, protrusion 201 of interface
200 has a height 201 A (Figure 10B) that exceeds height 214A (Figure 11 ) of
cutout regions 214. In one embodiment, height 201A is approximately twice
that of height 214A. This preferred configuration prevents improper
engagement of latch portion 212 with interface 200 due to any over-rotation of
latch 90 in the counter-clockwise direction during the resetting operation
described above with respect to Figure 9. In particular, it prevents the
bottom
surface of latch portion 212 near cutout region 214 from improperly contacting
and abutting top surface 201 B (Figure 1 OB) of protrusion 201 which would
keep bottom surface 213A (Figure 11 ) of protruding region 213 floating
(disengaged) and undesirably alter the latch load relationship of trip
mechanism 40.
As shown in Figure 14, spring 202 is positioned in channel 199 of trip
shaft 192 with end 202C of spring 202 rotated counter-clockwise (shown with
dashed lines) from its vertical position (shown with solid lines) and
positioned
under and in pressurized contact with intermediate latch 90. In particular,
end
202C is positioned under and in pressurized contact with an undersurface
209A of an elbow area 209 (Figure 11 ) of latch 90. Positioned as such, end
202C of spring 202 applies a bias force to latch 90 in the counter-clockwise
rotational direction, for reasons discussed below. The configuration, size,
and
positioning of spring 202 is chosen so that the bias force provided by end
202C is, at all times, smaller in magnitude than the spring forces experienced
by cradle 72, thereby always enabling the cradle spring forces to rotate latch
90 in a clockwise direction (as described above) when latch 90 and latch
interface 200 are disengaged due to a tripping operation. When latch 90 has
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been rotated clockwise due to a tripping operation as such, the cradle spring
forces are no longer felt by latch 90 after cradle 72 has rotated counter-
clockwise and lower portion 92 of latch cutout region 94 no longer contacts
latch 90. The bias force provided by end 202C of spring 202 then takes over
and rotates latch 90 in the counter-clockwise direction. The configuration,
size, and positioning of spring 202 is chosen so that the bias force rotates
latch 90 in the counter-clockwise direction only to a point where upper latch
portion 210 is properly positioned to make contact with upper portion 93 of
latch cutout region 94 during the resetting operation described above with
respect to Figure 9. The counter-clockwise rotation of latch 90 due to end
202C of spring 202 advantageously prevents upper latch portion 210 from
being left in a clockwise over-rotated position (due to the cradle spring
forces)
where latch portion 210 is in too vertical of a position such that, during the
resetting operation, it could undesirably contact upper portion 93 of latch
cutout region 94 at an angle that would prevent or make it difficult for latch
90
to be rotated counter-clockwise (this rotation being necessary for lower latch
portion 212 to become latched with latch interface 200, as described above).
As described above, protrusions or stops 220 are provided in
sideplates 84 in order to limit the clockwise rotation of latch 90. Although
these protrusions ideally prevent clockwise over-rotation of latch 90 into too
vertical of a position, variability in parts may limit their ability to
accomplish
this goal. By supplying a constant bias force on latch 90 in the counter-
clockwise direction, end 202C of spring 202 cooperates with stops 220 to
ensure that the desired over-rotation protection exists.
There are several types of tripping operations that can cause trip bar
assembly 190 to rotate in the clockwise direction and thereby release cradle
72. One type is a manual tripping operation, and the structure associated
therewith is shown in Figure 15. Figure 15 shows a portion of the internal
workings of circuit breaker 10 within base 12, with base 12 having been cut
away at 226A and 226B to provide a better view thereof. Shown is trip bar
assembly 190 and manual trip bar 198 thereof. Along the outer sidewall of
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base 12 is a push-to-trip actuator 230 of trip mechanism 40 that is positioned
such that it can be moved upwardly or downwardly. Actuator 230 includes a
button 25 with a top portion 25A that protrudes through rectangular opening
23 of cover 14 (Figure 1 ).
Referring now also to Figures 16A and 16B, push-to-trip actuator 230
is comprised of a main bar-like member 231 that slightly tapers near its
bottom 232 where it slideably fits into a groove formed between housing
structures 228 and 229 and the outer sidewall of base 12 (Figure 15). This
groove provides a guide for the vertical motion of push-to-trip actuator 230.
Actuator 230 includes a stop member 235 that is positioned to abut housing
structure 229 in order to limit the downward movement of actuator 230 within
this groove. For reasons discussed below, a spring (not shown) is seated
between bottom 232 of actuator 230 and the bottom of base 12. Near its top,
actuator 230 includes shoulders 233 from which upwardly protrudes a curved
flange 234. Button 25 sits upon shoulders 233 and, as shown in Figure 17,
includes an appropriately configured opening 236 into which curved flange
234 is inserted. Button 25 also includes a shoulder 237 which abuts upwardly
against a bottom surface of cover 14 so as to limit the upward vertical
movement of push-to-trip actuator 230, and a cut-out section 238 for
providing clearance for handle 24 and its associated handle slider, as
described in greater detail below. Protruding outwardly from approximately
the middle of main member 231 of push-to-trip actuator 230 is a downwardly
curved arm 240 with a bottom portion 242. As shown in Figure 15, bottom
portion 242 of arm 240 is positioned just above manual trip bar 198 of trip
bar
assembly 190.
When top portion 25A of button 25 is depressed, the resulting
downward movement of push-to-trip actuator 230 causes bottom portion 242
of arm 240 to contact manual trip bar or member 198, thereby causing trip bar
assembly 190 to rotate in the clockwise direction. As described above, this
rotation of assembly 190 releases cradle 72 and results in the TRIPPED
disposition shown in Figure 8. The spring (not shown) positioned below
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bottom 232 of push-to-trip actuator 230 causes the actuator to return to its
initial position when force upon top portion 25A of button 25 is no longer
exerted.
In a preferred embodiment, push-to-trip actuator 230 (except button
25) is comprised of a metal such as carbon steel, and is integrally formed via
a stamping process. As such, the strength of the main portion of actuator 230
is enhanced, enabling it to have thinner dimensions which are highly
desirable in view of the space constraints of modern circuit breakers such as
circuit breaker 10. In the exemplary embodiment, the carbon steel of actuator
230 is .045 inches thick. Button 25 is preferably comprised of a suitable
polymer (plastic) with electrical insulating properties.
In addition to the manual tripping operation described above, circuit
breaker 10 includes automatic thermal and magnetic tripping operations
which likewise can cause trip bar assembly 190 to rotate in the clockwise
direction and thereby release cradle 72. The structure for providing these
additional tripping operations can be seen in Figure 7 which shows circuit
breaker 10 in its ON (non-TRIPPED) disposition, with latch 90 abutted hard
against lower portion 92 of latch cutout region 94 of cradle 72, and latch 90
held in place by intermediate latch interface 200 (Figure 10B) of trip bar
assembly 190. Also shown is an automatic trip assembly 250 of trip
mechanism 40 that is positioned in close proximity to trip bar assembly 190.
Referring now also to Figures 18A, 18B, 18C, 19A, 19B, 20, 21, 22A,
and 22B, shown in isolation is automatic trip assembly 250 and its various
components. Assembly 250 includes a magnetic yoke 252, a bimetal 254, a
magnetic clapper or armature 256, and load terminal 28. Magnetic yoke 252
(Figures 19A and 19B) includes a substantially planar portion 258 with a
bottom portion 258A. Protruding from portion 258 are curved arms or wings
260 and 262 having front faces 260A and 262A. At the tops of arms 260 and
262 are pivot supports 264 and 266, with respective pivot surfaces 268 and
270 on which pivot magnetic clapper 256, as described below. Pivot support
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264 includes a front retaining ridge or raised surface 263 that helps define
pivot surface 268, and pivot support 266 includes a downwardly facing stop or
protrusion 265. Pivot supports 264 and 266 each include a rear retaining
protrusion 267 which helps define pivot surfaces 268 and 270. Yoke 252 also
includes a shoulder portion 272 above which is positioned a portion of load
terminal 28, as described below. In addition, holes or openings 274 are
formed through substantially planar portion 258 for purposes described
below. Yoke 252 of the exemplary embodiment is made of carbon steel
material of approximately .078 inch thickness.
Bimetal 254 (Figure 20) is planar and substantially rectangular in form
and includes two cutout regions 280 and 282 forming a neck 284 upon which
sits a head portion 286. Through a bottom portion 287 of bimetal 254 is a
hole or opening 288 for purposes described below. Bimetal 254 is structured
as is known to one of skill in the art such that bottom portion 287 deflects
(bends) in a conventional manner above certain temperatures.
Magnetic clapper 256 (Figure 21 ) is planar in form and includes cutout
regions 312 and 314 which form shoulders 313 and 315, a neck portion 311,
and a head portion 316. Head portion 316 includes horizontal pivot portions
or arms 318, and the outside corner of shoulder 315 includes a chamfered
region or cutout 317. The body of clapper 256 is wider than the body of
magnetic yoke 252, with distance d2 greater than distance d1 (Figure 19B).
Clapper 256 includes holes or openings 320 formed within a bottom portion
319 for purposes described below, and is formed of carbon steel material in
the exemplary embodiment.
Load terminal 28 (Figures 22A and 22B) includes a substantially planar
portion 290 from which protrudes, in approximately perpendicular fashion, a
bottom connector portion 292 that connects with an external input of
electrical
current by means of a connecting device such as a self-retaining collar. Such
a collar provides both a physical and electrical connection, and an example
collar 295 is shown in Figure 4 (connected to connector portion 292 as well
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as to a similar portion of line terminal 29) and is described in greater
detail
below in connection with Figure 29. For purposes described below with
respect to Figure 29, connector portion 292 has a hole or opening 294, raised
portions or surfaces 297 on the top thereof, and cut-outs 299 that cause front
face 301 to have a smaller width than the rest of connector 292. Located at
the other end of terminal 28 is a top substantially planar region 296 which is
offset from portion 290 via a curved region 298. Formed through portion 290
are holes or openings 300, 302, and 304. A tab or protrusion 306 protrudes
from one side of portion 290 near hole 304. Planar portion 290 includes
offsets or ribbed portions 308 formed along the sides thereof. As best seen in
Figure 22A, planar portion 290 slightly tapers along its length in a gradual
manner, with width w2 wider than width w1.
Referring briefly now also to Figures 23-27, shown in Figure 23 is a
portion of base 12 into which load terminal 28 mounts when assembled into
circuit breaker 10. Base 12 includes channels 520 formed in both sides
thereof, each with a bottom 522. As shown in Figure 24, the sides of planar
portion 290 of load terminal 28, and in particular ribbed portions 308, insert
into channels 520 until bottom shoulders 291 (see Figure 22B) of terminal 28
abut the bottoms 522 of channels 520. Inserted as such, with an interference
fit provided by ribs 308, lateral movement of terminal 28 relative to base 12
is
prevented. The sides of base 12, and therefore channels 520 formed therein,
are slightly tapered from top to bottom, as best shown in Figure 25, with
distance d2 greater than distance d1. This tapering aids in the molded
production of base 12. The tapering of planar portion 290 of terminal 28
follows this tapering of base 12 so as to provide a snug fit therewith upon
insertion. Ribbed portions 308 enhance the frictional engagement between
terminal 28 and channels 520, thereby also resisting vertical movement of
terminal 28 relative to base 12. In order to further prevent vertical movement
of terminal 28 relative to base 12, cover 14 includes an abutment portion or
wall 525, as shown in Figures 26 and 27, having a bottom that is
appropriately positioned and dimensioned to abut protrusion 306 of terminal
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28 when cover 14 is in a position of securement with base 12. This abutment
holds protrusion 306 down, thus keeping terminal 28 fully seated in channels
520. In the exemplary embodiment, the bottom of abutment wall 525 includes
a contact member or crush rib 526 that is positioned to directly contact
protrusion 306 when cover 14 is secured to base 12. Rib 526 is formed of
compressible material, thereby providing a little "give" to the abutment of
wall
525 with protrusion 306 and ensuring proper fit notwithstanding slight
variability in the circuit breaker components in issue. In one embodiment,
crush rib 526 is formed of a thermoset glass polyester material like the rest
of
cover 14 but with a reduced amount of fiberglass in order to provide
enhanced compressibility.
Figures 18A and 18B show automatic trip assembly 250 in assembled
form. Neck 284 of bimetal 254 is positioned between arms 260 and 262 of
yoke 252 whereby bimetal 254 is substantially parallel (but not in contact)
with
portion 258 of yoke 252. A screw 255 is shown partially screwed into one
side of opening 288 in bottom portion 287 of bimetal 254, for reasons
discussed below. Head portion 286 of bimetal 254 is connected to top region
296 of load terminal 28 by way of a conventional heat welding or brazing
process. Curved region 298 of load terminal 28 is positioned above shoulder
272 of yoke 252, with planar portion 290 of terminal 28 parallel and in
contact
with planar portion 258 of yoke 252. Securing terminal 28 to yoke 252 are
securing devices such as rivets 330 which are inserted into holes 274 of yoke
252 and corresponding holes 300 of terminal 28. Secured in this manner,
terminal 28 advantageously has only one heat-affected zone which is in the
area of top region 296. Positioned in contact with (seated in) pivot surfaces
268 and 270 of yoke 252 are pivot arms 318 of magnetic armature 256 for
providing a limited range of motion of clapper 256, as discussed in more
detail below. As seen in Figure 18C, chamfered region or cutout 317 of
armature 256 facilitates this positioning of the armature during the assembly
process. Armature 256 is first tilted (as shown) with cutout 317 positioned
below pivot support 266 and stop 265 thereof. Cutout 317 provides clearance
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that enables arm 318 above cutout region 314 to then be rotated into contact
with pivot surface 270. Arm 318 above cutout region 312 can then be easily
swung over the end of pivot support 264 and into contact with pivot surface
268. During operation of circuit breaker 10, pivot arms 318 are maintained in
contact with pivot surfaces 268 and 270 by way of retaining member 263 and
retaining protrusions 267 of yoke 252. Two springs 253 (only one is clearly
shown) are attached to and disposed between holes 320 of clapper 256 and
holes 302 of terminal 28, with curved ends or hooks 253A of springs 253
protruding through the holes and providing the attachment. Springs 253 have
a tendency to maintain a predetermined distance between bottom portion 319
of magnetic clapper 256 and front faces 260A and 262A of magnetic yoke
252, and to maintain clapper 256 in a position that is rotationally displaced
in
a clockwise manner from vertical (away from yoke 252). As seen in Figure
18A, stop or protrusion 265 of pivot support 266 is positioned to make contact
with a clockwise rotated clapper 256 (near shoulder 315), defining a
maximum angle of rotational displacement of clapper 256.
When implemented in circuit breaker 10 as shown in Figure 7,
automatic trip assembly 250 operates to cause a clockwise rotation of trip bar
assembly 190, thereby releasing cradle 72 which leads to the TRIPPED
disposition described above in connection with Figure 8, whenever
overcurrent conditions exist in the ON disposition. In the ON disposition as
shown in Figure 7, electrical current flows (in the following or opposite
direction) from load terminal 28, through magnetic yoke 252 and bimetal 254,
from bottom portion 287 of bimetal 254 to movable contact arm 50 through a
conductive cord 289 (shown in Figure 3) that is welded therebetween, through
closed contacts 52 and 56, and from stationary contact arm 54 to line terminal
29. Automatic trip assembly 250 reacts to an undesirably high amount of
electrical current flowing through it, providing both a thermal and a magnetic
tripping operation.
The thermal tripping operation of automatic trip assembly 250 is
attributable to the reaction of bimetal 254 to current flowing therethrough.
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The temperature of bimetal 254 is proportional to the magnitude of the
electrical current. As current magnitude increases, the heat buildup in
bimetal
254 has a tendency to cause bottom portion 287 to deflect (bend) to the left
(as viewed in Figure 7). When non-overcurrent conditions exist, this
deflection is minimal. However, above a predetermined current level, the
temperature of bimetal 254 will exceed a threshold temperature whereby the
deflection of bimetal 254 causes bottom portion 287 to make contact with
thermal trip bar or member 194 of trip bar assembly 190. This contact forces
assembly 190 to rotate in the clockwise direction, thereby releasing cradle 72
which leads to the TRIPPED disposition. The predetermined current level
(overcurrent) that causes this thermal tripping operation can be adjusted in a
conventional manner by changing the size and/or shape of bimetal 254.
Furthermore, adjustment can be made by selectively screwing screw 255
(Figure 18A---not shown in Figure 7) farther into opening 288 such that it
protrudes to a certain extent through the other side of bimetal 254 (towards
thermal trip member 194). Protruding as such, screw 255 is positioned to
more readily contact thermal trip member 194 (and thus rotate assembly 190)
when bimetal 254 deflects, thus selectively reducing the amount of deflection
that is necessary to cause the thermal tripping operation.
Cutout regions 280 and 282 of bimetal 254 have rounded corners
280A and 282A (Figure 20), respectively, which ease and facilitate the higher
density downward current flow in those regions (during the ON disposition of
circuit breaker 10) caused by the narrowing of the flow path of current
between head portion 286 and neck 284. In an assembled automatic trip
assembly 250, cutout region 282 extends down the length of bimetal 254
substantially past the bottom of arms 260 and 262 of magnetic yoke 252 (see
Figure 18A) in order to prevent interference with other internal and/or
housing
components positioned in close proximity thereto. In contrast, cutout region
280 extends to a point approximately just below the bottom of arms 260 and
262. This provides for a wider bimetal 254 below arms 260 and 262 of
magnetic yoke 252 which reduces the susceptibility of those portions of
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bimetal 254 to increased eddy current effect heating that could cause an
annealing or pitting of that area during high (interrupt) current conditions.
Automatic trip assembly 250 also provides a magnetic tripping
operation. As electrical current flows through magnetic yoke 252, a magnetic
field is created having a strength that is proportional to the magnitude of
the
current. This magnetic field generates an attractive force that has a tendency
to pull magnetic clapper 256 towards front faces 260A and 262A of yoke 252.
The magnitude of this attractive force is enhanced because, as described
above, the body of clapper 256 is wider than the body of yoke 252. When
non-overcurrent conditions exist, the tension provided by springs 253
connected between holes 320 of clapper 256 and holes 302 of load terminal
28 prevent any substantial rotation of clapper 256. However, above a
predetermined current level, a threshold level magnetic field is created that
overcomes the spring tension, compressing springs 253 and enabling bottom
portion 319 of clapper 256 to forcefully rotate counter-clockwise towards
front
faces 260A and 262A of yoke 252. During this rotation, bottom portion 319 of
clapper 256 makes contact with magnetic trip bar or member 196 which, as
shown in Figure 7, is partially positioned between clapper 256 and front faces
260A and 262A of yoke 252. This contact moves the end of trip bar 196
substantially between curved arms 260 and 262 of yoke 252, thereby forcing
trip bar assembly 190 to rotate in the clockwise direction. This leads to the
TRIPPED disposition as described in detail above in connection with Figure 8.
As with the thermal tripping operation, the predetermined current level that
causes this magnetic tripping operation can be adjusted. Adjustment may be
accomplished by implementation of different sized or tensioned springs 253
that are connected between bottom portion 319 of clapper 256 and load
terminal 28.
In Figures 7, 18A, and 18B, it can be seen that portions 258 and 258A
of magnetic yoke 252 substantially extend between bimetal 254 and load
terminal 28. This positioning of metallic magnetic yoke 252 causes a general
reshaping of the magnetic flux lines that are generated by the oppositely
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flowing currents in terminal 28 and bimetal 254 during the ON disposition of
circuit breaker 10. By reshaping the flux lines, this configuration limits the
interference between the flux lines, thereby reducing the outward blowoff
force between terminal 28 and bimetal 254 that is generated during high
(interrupt) current conditions. This reduction in blowoff force reduces the
likelihood of the force causing terminal 28 and bimetal 254 to undesirably
break apart during such high current conditions.
Figures 22A and 22B depict an embodiment of load terminal 28 that
may be used in circuit breaker 10. That embodiment, formed of stamped
stainless steel having a thickness of approximately .047 inches, is most
useful
in applications where electrical current will normally be below approximately
30 amps. For higher current applications, another embodiment of a load
terminal may advantageously be used, as shown in Figures 28A, 28B, and
23C. In order to better accommodate the higher currents, terminal 28A of this
embodiment is formed of stamped copper or brass of an increased thickness
of approximately .093 inches. Terminal 28A includes a substantially planar
portion 330 (again tapered) from which protrudes, in approximately
perpendicular fashion, a bottom connector portion 332 with a hole or opening
334 extending therethrough. Connector 332 also includes indents 331 on the
top thereof, cutouts 333 that cause front face 335 to have a smaller width
than the rest of connector 332, and a notch or cutout 337 extending from the
bottom of front face 335 towards opening 334, as shown in Figure 28C.
Located at the other end of terminal 28A is a top substantially planar region
336 which is offset from portion 330 via a curved region 338. Formed through
portion 330 are holes or openings 340 (for securement to magnetic yoke 252)
and holes or openings 342 (for attachment of the two springs 253). A tab or
protrusion 344 (having the same purpose as protrusion 306 of terminal 28)
protrudes from one side of portion 330, with a corresponding cavity 346 on
the other side. Ribbed portions 348 are also formed in portion 330 for the
reasons described above with respect to ribbed portions 308 of terminal 28.
Ribbed portions 348 are not as pronounced as ribbed portions 308 due to the
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general increased thickness of terminal 28A as compared to terminal 28,
although they provide a similarly snug fit within channels 520 of base 12.
Also shown are support ribs 350 for enhancing the strength of curved region
338. The operation of terminal 28A within circuit breaker 10 and, in
particular,
automatic trip assembly 250, is essentially the same as described above in
connection with terminal 28.
Referring now to Figure 29, shown is an example self-retaining collar
295 that may be used with either load terminal 28 (or 28A) or line terminal 29
to connect external conductors thereto. Collar 295 includes a base portion
480 having a substantially open-ended square shape. Base 480 includes
inwardly-facing detents or protrusions 482 formed in the two vertical sides
thereof, and an upwardly-facing circular protrusion or raised surface 484
formed on the bottom. A neck 486 is formed on the top of base 480, defining
an opening through which a top portion 488 is inserted. In the exemplary
embodiment, top portion 488 is a screw having a clamp portion 490 rotatably
connected to the bottom thereof.
In use, collar 295 is connected onto the end of one of the terminals of
circuit breaker 10. Describing this connection with respect to load terminal
28
shown in Figures 22A and 22B, connector portion 292 of terminal 28 is
inserted into base 480 such that raised surfaces 297 abut detents 482, and
until opening 294 is engaged by circular protrusion 484. Cutouts 299 of
terminal 28 facilitate this insertion because they enable front face 301,
which
has a width that is smaller than the inner width of base 480, to easily slide
in
and "channel" the remainder of connector 292 therein. Protrusion 484 of
collar 295 provides an interference fit with opening 294 that resists lateral
movement of the collar relative to terminal 28. Detents 482 of collar 295
prevent vertical movement of the collar relative to terminal 28, and the
enhanced frictional engagement provided by raised surfaces 297 of connector
292 also resists lateral movement of the collar relative to terminal 28.
Positioned as such (as shown in Figure 4), collar 295 is in a self-retained
disposition.
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Describing the connection of collar 295 with respect to load terminal
28A shown in Figures 28A and 288, connector portion 332 of terminal 28A is
likewise inserted into base 480 such that its top surface abuts detents 482,
and until opening 334 is engaged by circular protrusion 484. Like cutouts 299
of terminal 28, cutouts 333 of terminal 28A facilitate this insertion and
provide
a similar channeling effect for the remainder of connector 332. Notch or
cutout 337 of connector 332 also facilitates the insertion because it is
appropriately sized and configured to channel circular protrusion 484 of
collar
295 under connector 332 which is beneficial since connector 332 is of
increased thickness as compared to connector 292 of terminal 28. Protrusion
484 of collar 295 provides an interference fit with opening 334 that resists
lateral movement of the collar relative to terminal 28A. Detents 482 of collar
295 snap into indents 331 of connector 332, providing an interference fit that
also resists lateral movement of collar 295 relative to terminal 28A, with
detents 482 also preventing vertical movement of collar 295 relative to
terminal 28A. A self-retained disposition of collar 295 is thus realized.
After collar 295 is connected onto the end of one of the terminals of
circuit breaker 10, the end of an external conductor can then be inserted
between clamp 490 and the top surface of the terminal's connector portion.
Clamp 490 can then be lowered by means of rotation of screw 488 until the
clamp frictionally secures the external conductor to the terminal. External
access to screw 488 is provided by way of one of holes 20 in cover 14 (Figure
1 ) which enables a tool such as a screwdriver to be inserted and to
appropriately manipulate screw 488.
Referring now to Figures 30A and 308, shown are cradle 72 and
cradle pivot pin 82 of the present invention. As shown in Figures 12 and 13,
pin 82 is laterally and rotatably disposed between sideplates 84 of circuit
breaker 10, and provides a point of rotation for cradle 72. As shown in Figure
30A, cradle 72 has an opening 393 through which upper toggle link pivot pin
78 extends. Cradle 72 also includes an aperture 390 consisting of a smaller
cutout or hole 392 interconnected with (blending into) a larger cutout or hole
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394. Larger cutout 394 is sized so as to be larger than the thickest diameter
portion of pin 82. Before pin 82 is positioned between holes 396 and 398 of
sideplates 84 (see Figure 13), pin 82 is easily inserted midway through larger
cutout 394 of aperture 390. Because substantial pressure is not required in
order to insert pin 82 through cutout 394, pin 82 may advantageously be
heat-treated for strength so that it is more capable of withstanding the
higher
internal temperatures sometimes encountered in circuit breakers. As shown
in Figure 30B, pin 82 includes a stepped-inward portion 397 midway along its
length. Pin 82 (presently inserted in larger cutout 394) is then shifted such
that portion 397 becomes seated into smaller cutout 392, cutout 392 being
sized to provide engagement therewith while at the same time, in the
exemplary embodiment, enabling pin 82 to rotate therein. Because portions
397A of pin 82 around stepped-inward portion 397 are too thick to fit within
smaller cutout 392, they provide shoulders which ensure that cradle 72
remains centered on pivot pin 82. When pin 82 is then rotatably positioned
between holes 396 and 398 of sideplates 84, cradle 72 is able to rotate during
the tripping and resetting operations of circuit breaker 10 described above.
This rotation can occur in one of two manners: cradle 72 may rotate on
(independently of) pin 82, or cradle 72 may rotate with pin 82 (within holes
396 and 398 of sideplates 84). These two methods of rotation are
advantageous in that they provide increased flexibility to the operation of
operating mechanism 38. In particular, proper rotation of cradle 72 can still
occur even if pin 82 somehow locks up and cannot rotate within holes 396
and 398 of sideplates 84.
During the assembly process, stop bar 88 serves to help maintain the
engagement of stepped-inward portion 397 of pivot pin 82 with smaller cutout
392 of cradle 72. As shown in Figures 6 and 8, stop bar 88 is positioned
close to, and substantially to the left and below, an indent or cutout portion
395 of cradle 72 when the cradle is in an assembly-conducive position as
depicted. Positioned as such, stop bar 88 has a tendency to abut indent 395
if cradle 72 moves downwardly and/or to the left, thus preventing substantial
CA 02316744 2000-08-24
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movement in those directions which could result in a loose seating of pivot
pin
82 in larger cutout 394. In the totally assembled circuit breaker 10, the pair
of
side-by-side compression springs (not shown) acting upon cradle 72 provide
a spring force which also serves to keep smaller cutout 392 engaged with
stepped-inward portion 397 of pivot pin 82. Although stop bar 88 and the pair
of side-by-side compression springs maintain the aforementioned
engagement, they nonetheless enable a little "give" to exist in that
engagement whereby cradle 72 may advantageously move a small distance
about pivot pin 82 which provides increased flexibility to the operation of
operating mechanism 38.
Referring again to Figures 12 and 13, stop bar 88 is shown laterally
disposed between sideplates 84. Stop bar 88 includes ends 450 which are,
in the exemplary embodiment, of a smaller diameter than the main portion of
bar 88 and separated therefrom by shoulders 452. During assembly, ends
450 are inserted into holes 454 of sideplates 84 until shoulders 452 (which
have a larger diameter than openings 454) contact inner surfaces 84B of
sideplates 84. After this insertion, portions 450A of ends 450 protrude out of
holes 454 along the outer surfaces 84A of sideplates 84. A machine, such as
an orbital riveter, is then used to inwardly spin press portions 450A until
outer
shoulders 456 are formed (only one is shown) which, although of sufficient
thickness to be structurally firm, are thin enough so that they are
substantially
flush with respect to outer surfaces 84A of sideplates 84. Because outer
shoulders 456 have a larger diameter than openings 454, they cooperate with
inner shoulders 452 to help maintain the spacing between sideplates 84. In
particular, outer shoulders 456 will resist further outward separation of
sideplates 84 potentially caused by, for example, forces generated during
high current interruption. Inner shoulders 452 resist any inward movement of
sideplates 84 (towards each other) that could potentially occur. This
maintenance of the spacing between sideplates 84 serves to help ensure
proper positioning and functioning of operating mechanism 38 components.
Also shown in Figures 12 and 13 is a support bar 460 laterally
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disposed between sideplates 84. Similar to stop bar 88, support bar 460
includes ends 462 which are, in the exemplary embodiment, of a smaller
diameter than the main portion of bar 460 and separated therefrom by
shoulders 464. During assembly, ends 462 are inserted into holes 466 of
sideplates 84 until shoulders 464 (which have a larger diameter than
openings 466) contact inner surfaces 84B of sideplates 84. After this
insertion, portions 462A of ends 462 protrude out of holes 466 along the outer
surfaces 84A of sideplates 84. A machine, such as an orbital riveter, is then
used to inwardly spin press portions 462A until outer shoulders 468 are
formed (only one is shown). Although outer shoulders 468 are of sufficient
thickness to be structurally firm, they are thin enough to be substantially
flush
with respect to outer surfaces 84A of sideplates 84. Because outer shoulders
468 have a larger diameter than openings 466, they cooperate with inner
shoulders 464, and with stop bar 88, to help maintain the spacing between
sideplates 84, in the manner described above in connection with stop bar 88.
In a preferred embodiment, stop bar 88 and support bar 460 are
formed of carbon steel metal. In addition, holes 466 for support bar 460 are
preferably formed in areas of sideplates 84 that are substantially on the
opposite side of where holes 454 are formed for stop bar 88. Such
positioning of stop bar 88 and support bar 460 provides for proper spacing
maintenance of sideplates 84 along their entire length. In the exemplary
embodiment, support bar 88 is positioned between trip bar assembly 190 and
crossbar assembly 60, the exact positioning and size thereof selected so that
it does not interfere with rotation of those components. In other
embodiments, additional support bars may, of course, be used in order to
further ensure proper spacing between sideplates 84.
Referring now to Figure 31 and again to Figures 12 and 13, shown are
handle assembly 70 and associated parallel sideplates 84 of the sideplate or
support member assembly of circuit breaker 10. Handle assembly 70 is
formed of metal in the exemplary embodiment, and includes parallel and
symmetrical handle assembly plates 100 that are connected together by a
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handle platform 101 that interconnects with handle 24 of circuit breaker 10 as
described below. Each handle assembly plate 100 includes an opening 102
(only one of which is shown in Figure 31 ) through which handle assembly
roller 86 extends (Figure 5), and each also includes a circular pivot region
104
that rotatably mates with a corresponding pivot surface cutout 106 (Figure 12)
in each sideplate 84. Also shown are handle assembly actuation tabs or
protrusions 108 that protrude from the bottom of each handle assembly plate
100, each including an inwardly curved portion or contact member 109. Each
sideplate 84 includes an actuation tab cutout region 110, including a bottom
portion 111, that corresponds with each actuation tab 108 and provides for
clearance thereof throughout a range of motion of handle assembly 70 during
normal operation of circuit breaker 10, as described below. As shown in
Figures 12 and 13, each sideplate 84 also includes an opening 105 into which
is inserted the stem or shaft 107A of a stop or tab 107 having a head portion
1078. Stops 107 are configured so that they may be manufactured by a
screw-machining process. The end of each stem 107A is spin pressed, for
example by an orbital riveter, in order to secure stops 107 to sideplates 84,
with head portions 107B positioned along the outer surfaces 84A of the
sideplates and at least partially externally overlapping pivot surface cutouts
106. Secured as such, stops 107 prevent pivot regions 104 of handle
assembly 70 from becoming outwardly disengaged from pivot surface cutouts
106 in sideplates 84 due to, for example, outward forces generated during
high current interruption.
Referring now also to Figures 32 and 33, and again to Figures 6 and 7,
shown in Figure 32 is cam housing 62 of crossbar assembly 60 without a cam
follower inserted therein. Disposed on and protruding generally from the top
of cam housing 62 are stop members 112. Figure 7 depicts the disposition of
cam housing 62, sideplates 84, and handle assembly 70 when circuit breaker
10 is in the ON disposition. Note that, in order to provide for a normal range
of movement of handle assembly 70 towards an OFF position, actuation tabs
or arms 108 are separated from the bottom portion 111 of cutout region 110.
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The tops of stop members 112 are internally positioned between sideplates
84 adjacent to actuation tab cutout regions 110 and not far below curved
portions 109 of actuation tabs 108. As such, stop members 112 are
positioned to abut against curved portions 109 when handle 24 is attempted
to be moved clockwise towards an OFF position at a time when contacts 52
and 56 and crossbar assembly 60 nonetheless remain in the ON disposition
(such as when contacts 52 and 56 are in a welded-closed disposition). This
abutment (shown in Figure 33), which occurs after a slight rotational
movement of handle assembly 70, prevents further movement of assembly 70
in the clockwise direction (through the range of motion normally enabled by
cutout regions 110), thereby preventing handle 24 from indicating that circuit
breaker 10 in in the OFF disposition when in fact it is not. As such, a clear
indication is provided that contacts 52 and 56 have not opened even though
an opening operation has been attempted. However, in normal operation
when contacts 52 and 56 can be opened, stop members 112 rotate clockwise
with crossbar assembly 60 (and contact 52) when handle assembly 70 is
moved clockwise towards the OFF position. As such, stop members 112
rotate away from actuation tab cutout regions 110, as shown in Figure 6. This
allows for full movement of actuation tabs 108 within regions 110 which, in
turn, allows handle 24 to move to the OFF position.
Referring now also to Figures 34A, 34B, 34C, and 34D, shown is
handle 24 of circuit breaker 10 which, in the preferred embodiment, is molded
of an insulator material such as plastic. Handle 24 includes a top portion
403,
and a base 404 having a top curvilinear surface 405 and a bottom cavity
region 406. Cavity region 406 includes protrusions 408 that define two
channels 407 into which sides 101A and 101 B of handle platform 101 (Figure
31 ) of handle assembly 70 are inserted (as shown in, for example, Figures 4,
5, and 6) to form an engagement connecting handle 24 to assembly 70. This
connection enables manual movement of handle 24 to cause operating
mechanism 38 to change disposition, as described above. Disposed
approximately midway within one channel 407 (in the exemplary
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embodiment), between protrusions 408, is an integrally formed protrusion or
nubb 409 (Figure 34D) which, like the rest of handle 24, is preferably formed
of an insulating material such as plastic which is at least partially
compressible. Side 101 B of platform 101 (Figure 31 ) includes, approximately
midway therein, an indent or cutout 411 of approximately the same size and
shape as protrusion 409. When platform 101 of handle assembly 70 is
inserted into channels 407, protrusion 409 will deform (compress) slightly as
it
travels over the flat portions of sides 101 B. As shown in the exemplary
embodiment, protrusion 409 is preferably rounded in shape so as to facilitate
this travel. When platform 101 is fully inserted into channels 407, protrusion
409 will return to its normal shape and become seated within indent 411. As
such, protrusion 409 and indent 411 serve to center the connection between
handle 24 and handle platform 101. In addition, the frictional engagement of
protrusion 409 with indent 411 serves to resist movement of platform 101
within channels 407, thereby providing a more secure connection between
platform 101 and handle 24. In an alternative embodiment, a protrusion 409
may be disposed in each channel 407, with corresponding indents 411
formed in both of sides 101 A and 101 B of platform 101.
As shown in Figure 34B, base 404 of handle 24 includes a first side
410 with a curvilinear top surface section 405A and terminating with an end
portion 414 which (in the exemplary embodiment) is substantially triangular in
shape. A second side 416 is somewhat symmetrical to that of first side 410,
except that it terminates with an end portion 418 that is truncated in
comparison to end portion 414, providing a truncated curvilinear top surface
section 405B. In the exemplary embodiment, end portion 418 is substantially
concave in shape. Truncated end portion 418 clearly occupies less space
than end portion 414, and is configured so as to not interfere (make contact)
with other internal workings of circuit breaker 10 throughout the range of
motion of handle 24. In particular, end portion 418 is configured so as to not
interfere with automatic trip assembly 250 of trip mechanism 40 when circuit
breaker 10 is in the OFF disposition or during a resetting operation, as shown
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in Figures 6 and 9, respectively.
Referring now also to Figures 35-38, shown in Figure 35 is a curved
handle slider 424 having an opening 426, a convex top surface 428, and a
concave bottom surface 430. Within circuit breaker 10, slider 424 is
positioned in a substantially overlapping relationship with handle 24 whereby
bottom surface 430 is placed on top of and substantially overlaps top surface
405 of handle 24, and top portion 403 of handle 24 protrudes through opening
426. As shown in Figures 36 and 37, handle 24 and overlapping slider 424
are positioned in relation to cover 14 whereby top portion 403 of handle 24
also protrudes through opening 22 of the cover. In a conventional manner,
slider 424 moves along a bottom surface 434 of cover 14 as handle 24 is
rotated through its range of motion. The overlapping relationship of slider
424
with handle 24, along with the fact that (in the exemplary embodiment)
opening 426 of slider 424 is smaller than opening 22 of cover 14, provides a
barrier which helps to prevent foreign items entered into opening 22 from
reaching the internal workings of circuit breaker 10. For this purpose, slider
424 preferably is thick enough such that it will not easily flex inward. In a
preferred embodiment, slider 424 is approximately .055 inches thick of celcon
thermoplastic material. Although thick enough to resist significant inward
flex,
slider 424 is relatively thin compared to base 404 of handle 24, and is thin
enough to arc or ride over automatic trip assembly 250 of trip mechanism 40
without interference (as can be seen in Figure 3).
As handle 24 is rotated through its range of motion, top surface 428 of
slider 424 makes contact with bottom surface 434 of cover 14 along arches
436 thereof. This contact reduces the chances of separation that could
compromise the barrier protection described above. As best shown in Figure
38, base 404 includes grooves 438 that extend along the side edges of top
surface 405 from end portion 414 to end portion 418. As top surface 428 of
slider 424 makes contact with arches 436 of cover 14 throughout the range of
motion of handle 24, this contact causes a slight deflection of the side edges
of slider 424 into grooves 438. This deflection reduces the friction between
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slider 424 and bottom surface 434 of cover 14, enabling handle 24 to
smoothly rotate through its range of motion. As such, grooves 438 enable a
thicker slider 424 to be implemented than otherwise would be possible within
the tight space constraints of circuit breaker 10, making the slider more
resistant to inward flex and thus providing enhanced barrier protection. In
the
exemplary embodiment, grooves 438 are approximately .030 inches deep.
In addition to having a truncated end portion 418, base 404 of handle
24 includes a cut-away section 440 near one corner of end portion 418, as
best shown in Figures 34A and 34D. As shown in Figure 15, cut-away
section 440 provides clearance for button 25 of push-to-trip actuator 230,
particularly when circuit breaker 10 is in the OFF disposition or during a
resetting operation. As also shown in Figure 15, working in conjunction with
cut-away section 440 is cutout 238 of button 25 which is positioned to provide
clearance for slider 424 (not shown) throughout the range of motion of handle
24. Cutout 238 is sufficiently large so that top portion 25A of button 25 can
be depressed notwithstanding the presence of slider 424 within cutout 238.
As such, cutout 238 of button 25 and cut-away section 440 of handle 24
cooperate in order to prevent interference between push-to-trip actuator 230
and the combination of handle 24 and slider 424.
Referring now to Figures 39 and 40, and again to Figure 2, particular
attention is directed to the profile between base 12 and cover 14 of circuit
breaker 10. Base 12 is shown having a top region generally designated 120,
and cover 14 is shown having a bottom region generally designated 122. Top
region 120 of base 12 includes raised portions 124 that mate with
corresponding cut-away or recessed portions 126 in bottom region 122 of
cover 14. As shown in the side cross-sectional view of Figure 40 taken along
the line 40-40 of Figure 1, when cover 14 is connected to base 12,
appropriate attaching devices 128 (comprising mounting screws in the
exemplary embodiment) are inserted into holes or openings 16 (Figure 2) in
cover 14 above recessed portions 126 and enter corresponding holes or
openings 18 in raised portions 124 of base 12. Attaching devices 128 are
CA 02316744 2000-08-24
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selected so that, upon full insertion, the bottoms thereof do not
substantially,
if at all, penetrate base 12 below its raised portions 124. As such, this
mounting arrangement conserves space within the main body of base 12
whereby attaching devices 128 do not interfere with the internal workings
therein. The dimensions of raised portions 124 and recessed portions 126
are selected so that attaching devices 128 can nonetheless penetrate a
sufficient depth into base 12 so as to provide a sufficiently strong
connection
between base 12 and cover 14. In one exemplary embodiment, attaching
devices 128 are approximately 1 inch in length and penetrate approximately
1/2 inch into raised portions 124 of base 12.
As shown in Figure 40 and described above, attaching devices 128
provide a mounting arrangement between base 12 and cover 14. Referring
now also to Figure 41, attaching device 128 of the exemplary embodiment is
shown including a main member 132 comprising a mounting screw with a
head 134 and a body separated into a non-gripping (non-threaded) portion
136 and a gripping (threaded) portion 138. Attaching device 128 also
includes a compressible member 140 that (when fully assembled) is adjacent
to head 134 and engaged by non-threaded portion 136 of mounting screw
132. Compressible member 140 may be an elastomeric washer (as in the
exemplary embodiment), or it may be another compressible device such as a
spring. In the cross-sectional view of Figure 40, attaching device 128 is
shown assembled and inserted into opening 16 (Figure 2) in cover 14 and
corresponding opening 18 in base 12. Figure 40 shows gripping portion 138
extending into and attaching with base 12, non-gripping portion 136 extending
through cover 14, and head 134 providing a stop for limiting the possible
separation between base 12 and cover 14. Compressible member 140 is
shown in a position between head 134 and a top surface of cover 14. In this
mounting arrangement, the compressibility of member 140 permits base 12
and cover 14 to temporarily and substantially instantaneously separate a
small distance when pressure develops within circuit breaker 10 such as due
to the generation of gases during high current interruption (opening of
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contacts 52 and 56). This separation along the interface between base 12
and cover 14 allows the generated gases to be vented, providing a pressure
release that protects the structural integrity of circuit breaker 10.
Referring now to Figures 42, 43, 44A, 44B, 45A, 45B, 45C, and 46,
shown are support members 150A and 150B of circuit breaker 10 in
connection with base 12 and cover 14. Base 12 includes sidewalls 152 within
which are formed slots 154A and 155A. As shown in Figure 43 which depicts
a top view of base 12 without components therein, sidewalls 152 also include
grooves or channels 156 adjacent to slots 154A, and grooves or channels
157 adjacent to slots 155A, both formed on the outer surfaces 152A of
sidewalls 152. Base 12 also includes small recesses 21 A formed in the top of
sidewalls 152. Cover 14 includes sidewalls 153 (only one of which is
viewable in Figure 42) within which are formed slots 1548 and 155B which
align with slots 154A and 155A, respectively, of base 12 when cover 14 is
positioned on top of base 12. Sidewalls 153 also include grooves or channels
that are similar to channels 156 and 157 of base 12.
Support member 150A includes a pair of shoulders or support wings
158 and a connection wall 160 therebetween, forming essentially an I-beam
as shown in Figures 44A and 44B. Support member 150A of the exemplary
embodiment also includes an opening 159 and a cutout region 161 that
substantially extends upwardly into wall 160. Support member 150B includes
a pair of shoulders or support wings 162 and a connection wall 163
therebetween, also forming essentially an I-beam as shown in Figures 45A,
45B, and 45C. In the exemplary embodiment, wall 163 includes an elongated
integral housing 164 having an upwardly extending cutout region 165.
In use, as shown in Figure 46, support member 150A is inserted into
slots 154A of base 12 whereby shoulders 158 engage grooves 156. In this
position, connection wall 160 is disposed internally within the body of base
12
and generally perpendicular to sidewalls 152. In relation to the other
internal
components of circuit breaker 10, support member 150A is disposed between
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arc extinguisher assembly 34 and slot motor assembly 32 in the exemplary
embodiment. In that position, the clearance provided by cutout region 161
facilitates the transfer of arcs (created by contact separation) to arc chute
46
of arc extinguisher assembly 34 in order to be dissipated, while wall 160
serves as a barrier for protecting the internal workings of circuit breaker 10
(those components to the left of support member 150A as viewed in Figure
46) from arcing and/or hot gases. Cutout region 161 also ensures that
movable contact arm 50 has sufficient room to move throughout its required
range of motion. Opening 159 provides clearance for upper arc runner 48A
(Figure 3) of arc chute 46 which is inserted therethrough.
As also shown in Figure 46, support member 1508 is inserted into
slots 155A of base 12 whereby shoulders 162 engage grooves 157. As such,
connection wall 163 is disposed internally within the body of base 12 and
generally perpendicular to sidewalls 152. In relation to the other internal
components of circuit breaker 10, support member 1508 is disposed between
slot motor assembly 32 and sideplates 84 in the exemplary embodiment. In
that position, cutout region 165 provides clearance for movable contact arm
50 to move throughout its required range of motion. Elongated housing 164
serves to fill vacant space between slot motor assembly 32 and sideplates 84,
and works with the rest of wall 163 to act as a barrier for protecting the
internal workings of circuit breaker 10 (those components to the right of
support member 1508 as viewed in Figure 46) from arcing and/or hot gases
potentially created by contact separation.
Cover 14 is then placed on top of base 12, whereby the tops of support
members 150A and 150B are inserted into slots 154B and 1558, respectively,
and shoulders 158 and 162 engage their respective grooves, as shown in
Figure 1. Disposed as such, the I-beam nature of each of support members
150A and 150B prevents or limits further separation of sidewalls 152 and 153
due to circumstances such as the buildup of pressure within circuit breaker 10
resulting from the generation of gases during high current interruption
(opening of contacts 52 and 56). In addition, shoulders 158 and 162 are
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appropriately dimensioned and manufactured of suitable material so as to
enable support members 150A and 150B to also allow venting of circuit
breaker 10 whereby pressure can be released. Upon a particular threshold
pressure within circuit breaker 10, the outer edges of shoulders 158 and 162
"wing" slightly outward (away from the grooves) to provide this outward
venting through slots 154A, 1548, 155A, and 1558, while at the same time
maintaining sidewalls 152 and 153 at or near a constant separation distance.
The width of connection walls 160 and 163 near shoulders 158 and 162,
respectively, are selected so as to permit such venting through the slots
notwithstanding the presence of those portions in the slots. Additional
venting is provided by openings 21 (Figure 1 ) which are formed at the
interface between recesses 21A of base 12 and the bottom of sidewalls 153
of cover 14. Openings 21 are small enough and appropriately configured so
that insertion of foreign items therein is substantially prevented.
Although two support members 150A and 150B are implemented in the
exemplary embodiment, other numbers of such support mechanisms may, of
course, be employed. Furthermore, the exact placement of one or more such
support members is preferably experimentally established via the analysis of
stress conditions in the base and cover of a particular circuit breaker. In
one
embodiment, support members 150A and 1508 are formed of molded
material comprising quantum 8800 (60% glass reinforced).
Now referring to Figures 47A and 478, shown is an insulation barrier or
deflector 500 of the present invention. Deflector or shield 500 includes a
vertical wall 502 having sides with channels or grooves 504. Integrally
connected to wall 502 is a shoulder 506 on which is formed a rounded cap
508. An opening 509 is formed in the top of cap 508, and an opening 510 is
formed in the underside of shoulder 506, forming a cylindrical cavity
therebetween. In one embodiment, deflector 500 is integrally molded of a
thermoset plastic material.
Now referring also to Figures 48 and 49, shown in Figure 48 is a side
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elevational view of the internal components of circuit breaker 10 without arc
extinguisher assembly 34. Line terminal 29 is shown connected to a self
retaining collar 295. In Figure 49, deflector 500 is shown positioned above
collar 295, with cap 508 on top of and covering screw 488 such that screw
488 may at least be partially inserted within opening 510. Vertical wall 502
of
deflector 500 is positioned along the side of collar 295 that normally faces
arc
extinguisher assembly 34.
Referring also now to Figure 50, shown is deflector 500 in relation to
base 12 and cover 14 (the other circuit breaker components, including collar
295, not shown for the sake of clarity). When deflector 500 is implemented
within circuit breaker 10, it is vertically slid into base 12 such that
grooves 504
engage vertically-extending protrusions 514 which are formed on the inner
surfaces 152B of sidewalls 152 (see also Figure 43). This engagement
substantially prevents any lateral movement of deflector 500 relative to base
12, and enables vertical wall 502 to extend substantially perpendicularly
between sidewalls 152 of base 12 without any gaps near its edges.
Protrusions or rails 514 are, of course, appropriately positioned in base 12
so
that a fully inserted deflector 500 is properly aligned with respect to the
collar
295 that is connected to line terminal 29. When cover 14 is secured to base
12, portions of cover 14 are positioned close to and above the top of cap 508
whereby vertical movement of deflector 500 relative to base 12 is also
substantially prevented. In addition, one of holes 20 of cover 14 aligns with
opening 509 of deflector 500, thereby enabling a tool such as a screwdriver to
be externally inserted into the cavity of cap 508 and to appropriately
manipulate screw 488 (Figure 29) of collar 295 in order to tighten or loosen
the connection of line terminal 29 to an external conductor.
Positioned as described above within circuit breaker 10, deflector 500
provides an insulation barrier for effectively protecting collar 295 from
arcing
and/or hot gases that may be generated within circuit breaker 10, particularly
during interruption of high currents.
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Referring now to Figures 51-54, shown is an example of a
conventional multi-wire lug assembly 360 that may be used as an accessory
for circuit breaker 10 to enable more than one conductor line to be routed
therethrough. Assembly 360 includes a body 362 with a plurality of lugs 364
arranged in step-like fashion thereon. Assembly 360 also includes a front
wall 365 from which protrudes an appropriately configured connector portion
366 that is insertable into load conductor opening 26 in base 12 (see Figure
1 ) and securable to load terminal 28 of circuit breaker 10 via a securement
device such as self retaining collar 295. Also shown is a lug insulator 370 of
the present invention. Insulator 370 includes a main body 372 formed of two
substantially parallel plates 374 with a wall 376 (Figure 52) therebetween.
Near its front, insulator 370 also includes an integral locking strap or
locking
structure 378 with two vertical side bars 379 and a horizontal bar 381
therebetween forming an opening 380 that is appropriately sized and
configured for insertion of connector 366 of lug assembly 360 therein. Each
plate 374 includes a tapered portion 382, a front portion 383, and, in the
exemplary embodiment, an internally disposed protrusion 384 (only one is
shown). In a preferred embodiment, insulator 370 is comprised of
thermoplastic material.
As shown in Figure 53, before connection to a circuit breaker, lug
assembly 360 may advantageously be assembled to lug insulator 370, with
body 362 placed between plates 374 and connector 366 inserted through
opening 380 of locking strap 378 until front wall 365 contacts bars 379 and
bar 381 of locking strap 378. Positioned as such, a top surface 363 of lug
assembly 360 abuts against the bottoms of protrusions 384 of plates 374.
This abutment, along with wall 376 (Figure 52) of insulator 370 and horizontal
bar 381 of locking strap 378, serves to help secure lug assembly 360 to lug
insulator 370 and prevent vertical separation therebetween. After the
aforementioned assembly, connector 366 of lug assembly 360 may then be
inserted, in normal fashion, into load conductor opening 26 in base 12 of
circuit breaker 10 (as shown in Figure 54) and secured to load terminal 28 via
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a securement device such as collar 295 (not visible). Note that front portions
383 of plates 374 abut against external surfaces of base 12, providing
enhanced stability to the connection. Once connector 366 is secured to load
terminal 28, insulator 370 is locked in place and cannot be separately
removed (pulled away) due to the contact between locking strap 378 thereof
and front wall 365 of lug assembly 360.
Lug insulator 370 provides electrical insulation for multi-wire lug
assembly 360. While providing this protective insulation, lug insulator 370
nonetheless provides easy access to lugs 364 of lug assembly 360. In
particular, tapered portions 382 of plates 374 follow the step-like
configuration
of lugs 364 so that convenient access is provided for all lugs.
Although the preferred embodiment of the present invention has been
described with a certain degree of particularity, various changes to form and
detail may be made without departing from the spirit and scope of the
invention
as hereinafter claimed.
