Note: Descriptions are shown in the official language in which they were submitted.
lZ~ 9
Field of the Invention
: The present invention relates to circuit breakers
with auxiliary switch mechanisms. More particularly,
the invention relates to auxiliary switch mechanisms
which indicate the status of the breaker. Still more
particularly, the invention relates to auxiliary
switch actuator ~echanisms which, once set, operate
only during an overcurrent condition to indicate an
electrically tripped condition of the breaker, and
which remain in their set state during normal manual
operation of the circuit breaker.
DescriPtion of the Related Art
Circuit breakers having auxiliary switch mechan-
isms are known. ~he auxiliary switch is usually con-
nected in an alarm circuit with an indicating device
(e.g., a light, bell, etc.~ to provide a remote indi-
cation of the condition of the breaker. Some of the
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more co~plex auxiliary circuits provide differing out-
puts responsive to the three b~sic breaker conditions:
manually OFF, manually ON, and electrically tripped.
Other common mechanisms provide an indication only
when the breaker has been electrically tripped.
More particularly, in some known breakers, the
auxiliary switch indicates whether the breaker is on
or off, the latter state being indicated whether the
breaker has been manually turned off or electrically
tripped. Breakers of this type thus do not discrimin-
, ate between manual operation and overcurrent condi-
j tions, and cannot be used effectively in applications
! which require an alarm signal to be generated when the
breaker is tripped by an overcurrent condition occur-
ring in the circuit.
I Other known breakers overcome this problem by pro-
! viding an auxiliary switch actuator mechanism which
discriminates between on, manual off, and overcurrent
, tripped conditions. ~owever, breakers of this type,
j one example of which is shown in U.S. Patent
¦ 3,742,402, issued June 26, 1973 to Nicol, require a
; complicated mechanical operating mechanism having a
multitude of parts which must be closely fitted into a
small space.
; These known breakers had the problem that in order
to provide a remote indication which distinguished
between normal breaker on and off conditions and the
i electrically tripped condition and provide signals
responsive to each, a complicated mechanism was re-
quired. The less complicated mechanisms were capable
of distinguishing only between on and off positions of
the breaker, whether the off position was attributable
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to manual operation or an overcurrent condition.
These problems were partially overcome by the develop-
ment of a simpler auxiliary switch actuator mechanism
that was capable of distinguishing between manual on/
off operation and the overcurrent tripped condition of
the breaker. An example of such a mechanism is shown
in U.S. Patent No. 3,593,232, issued July 13, 1971, to
! Shibuya et al. Howevér, these predecessor actuator
¦ mechanisms also have certain disadvantages. Their
I designs present manufacturi~g difficulties, particu-
I larly in trying to ensure reliability of operation.
! These mechanisms do not operate reliably leading to
¦ increased manufacturing costs and in some cases to
excessive numbers of returns. Furthermore, the com-
¦ mercial embodiment of the Shibuya device is unduly
I complex and would desirably be made using fewer parts.
¦ The present invention is directed to providing a
circuit breaker auxiliary switch actuator mechanism
! - which utilizes a simpler, more positive, and less cri-
¦ tically dimensioned mechanism than known devices,
I which provides a signal which indicates whether the
~ breaker is in normal operation (whether the breaker
I contacts are open or closed) or has tripped.
SUMMARY OF T~E INVENTION
The invention comprises an auxiliary switch actua-
tor mechanism for a circuit breaker. The breaker has
a frame, and a breaker mechanism mounted to the frame.
The breaker mechanism includes a manually operable
handle, a breaker contact pivotably mounted to the
frame and movable between open and closed positions, a
collapsible linkage coupling the handle and movable
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contact, and a sear pin cooperating with the collaps-
ible linkaqe to collapse the linkage upon aetection of
an overcurrent through the ~reaker. The actuator
mechanism includes an auxiliary switch having a mov-
able contact and an actuator ~ember coupled to the
auxiliary switch movablè bet~-een first and second pos-
itions for moving the auxiliary switch contact between
! normally-open and normally-closed positions, respect- ively.
~ In one embodiment, the actuator member has a base
j plate including a bifurcated portion at one end ex-
j tending outwardly in the longitudinal direction of the
I base plate and defining an open ended channel. Alter-
natively, the actuator member has a base member in-
cluding a locking arm receiving recess. The recess
has a stepped bottom surface, including a lower bot-
tom portion and an upper raised portion, having a de-
finite edge. In either case, an arm portion extends
upwardly from the base member to abùttingly engage the
j movable breaker contact when the movable breaker con-
tact is moved to its closed position. In this way,
closing of the movable breaker contact also closes the
- auxiliary switch.
The actuator mechanism also includes a locking
member having a central portion pivotably mounted di-
; rectly to the frame, preferably coaxially with the
movable breaker contact. This loc`~ing member comprises
first and second arms extending outwardly from the
central portion. The first arm has its distal end
portion disposed in the open ended channel or in the
recess in the locking arm housing of the actuator mem-
ber, and is biased thereagainst. In either case, the
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distal end of the first arm locks the actuator member
when the actuator member is aisposed in the closed
position, locking the auxiliary switch. The second
arm extends into the path of movement of the sear pin
when the sear pin is tripped. When tripped, the sec-
I ond arm is pivoted by t~e sear pin to pivot the first
i arm out of locking engagement with the actuator mem-
ber, thus releasing the auxiliary switch upon detec-
tion of an overcurrent condition. The sear pin does
I not contact the second arm when the breaker is manual-
J~ ly opened, such that the auxiliary switch is not
thereby affected.
~ The above-described features and advantages are
I best understood in view of the subsequent description
of the preferred embodiments of the present invention,
and in view of the accompanying drawings.
.
BRIEF DESCRIPTION OF TEE DRAWINGS
Figure 1 is a side view of the circuit breaker
mechanism in accordance with a first embodiment of the
;present invention with the circuit breaker in the ON
position;
Figure 2A is a front elevational view of a first
~ embodiment of the locking arm;
¦ Figure 2B is a side elevational view of the first
embodiment of the locking arm;
j Figure 3A is a top plan view of a first embodiment
¦ of the actuator member;
I Figure 3B is a side elevational view of a first
! embodiment of the actuator member;
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Figure 4 is a side perspective view of the locking
arm, the actuator member, and the auxiliary contact
switch in accordance with the first embodiment of the
present invention, showing the circuit breaker in the
tripped position;
I Figure 5 is a side view of the circuit breaker
mechanism in accordance with a second embodiment of
the present invention with the circuit breaker in the
' ON position;
! Figure 6A is a front elevational view of a second
embodi~ent of the locking arm;
Figure 6B is a side elevational view of a second
! embodiment of the locking arm;
Figure 7A is a top plan view of a second embodi-
ment of the actuator member;
Figure 7B is a side elevational view of a second
. embodiment of the actuator member; and
Figure 8 is a side perspective view of the locking
arm, the actuator member, and the auxiliary contact
switch in accordance with the second embodiment of the
present invention, showing the circuit breaker in the
tripped position.
DESCRIPTION OF TH~3 PREFERRED EMBODIMENTS
As mentioned, Shibuya et aL U.S. Patent 3,593,232
i shows a circuit breaker including an auxiliary switch
i which provides an unambiguous indication of tripping
j due to overcurrent. The device shown therein ~and the
I ~ commercial embodiment thereof) is unduly complex, has
! a large number of parts, and is difficult to
manufacture.
In particular, the Shibuya device includes a first
frame, not shown in the Shibuya patent, on which are
mounted the coil 3 and the armature 31. The pivot
axis of the moving contact arm 5 is defined by a pin
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carried in recesses in the two halves of the ~reaker
housing. IThis design is the source of some of the
assembly diffiGulties mentioned above) The collapsible
linkage and sear pin triggering assembly 21. 24, 25 and 23
is carried between pin 80 and a second pin 20, which in
turn is retained by a boss on the handle 18. In the
Shibuya patent, handle 18 includes two pins 1~ which fit
into recesses in the casing halves. In the commercial
device, these were molded integrally with the handle.
Finally, the locking lever for the auxiliary switch is
carried by a second frame 29. In the '232 patent, second
frame 2~ is located by pin 1~. The second frame in the
commercial embodiment of the Shibuya device is located by
pin 30 and by yet another pin fitting into recesses in the
case halves, which is not shown in the patent.
Figure 1 shows a preferred embodiment of the auxiliary
contact ~witch mechanism of the present invention as
incorporated into a cirGuit breaker. The circuit brea~er
10 comprises a case 12 formed of an electrically insulating
material, such as plastic. The case contains a breaker
mechanism, generally designated 14, which includes a
collapsible linkage mechanism operatively connecting a
handle 16 and a movable contact arm 18. A trigger
m~chanism which includes a sear pin 20, comprises a portion
of the breaker mechanism which controls the collapsible
linkage. The breaker mechanism 14, handle 16, and contact
arm 18 are all mounted to a frame 22. Upon passage
of an overcurrent through coil l, connected in circuit
between terminals 2 and ~, an end 4a of armature 4
pivoted about a pin 5 carried by frame 22 is attracted
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to the coil. Thereupon a second end 4b of the armature
is pivoted to strike sear pin 20 of the trigger
mechanism, causing the collapsible linkage to collapse,
tripping the breaker, and separating contacts 7 and 8
from one another. Representative breaker mechanisms
with which the present invention may be used are
disclosed in detail in commonly assigned U.S. Patent
No. 4,117,285 issued September 26, 1978 to Harper and
Canadian Patent Application Serial No. 452,412 filed
April 19, 1984 by Harper. Where not discussed herein,
other elements of the breaker of the invention are as
shown in these additional disclosures.
An auxiliary switch 24 is mounted in the lower
portion of casing 12. Typically, casing 12 is com-
posed of two halves, each of which contains pin mem-
bers 26 which mate with holes 28 in the auxiliary
switch 24 for mounting the auxiliary switch 2~ in the
proper position in the breaker 10. Typically, the
switch 24 comprises a microswitch assembly having a
set of auxiliary contacts which are operated by an
internal contact ~not shown). A movable pin 30 is
spring biased to extend upwardly through the plastic
housing of switch 24. Pin 30 engages the internal
contact to control its on-off operation. Such
switches are known in the art and are exemplified by
the switch shown in the Shibuya et al. ~.S. Patent
3,593,232, discussed above. The disclosure of the
'232 Shibuya patent is incorporated herein in its
entirety by reference as though set forth in full.
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In a first embodiment of, the present invention,
the movable pin 30 and hence the switch 24 are under
the immediate control of an actuator member 32.
Referring to Figures 3A and 3B, actuator member 32
comprises a base plate 34 and an arm 36 extending
upwardly from the base plate 34. The dista,l end of the
arm 36 terminates in a flange 38 having a downwardly
bent lip 40 at its end.'
A pair of pivot pins 42 extend laterally outwardly
from the plate 34 near an end 44 thereof. The longi-
tudinally opposite end 46 of plate 34 has a channel 48
formed therein to'thereby define a bifurcated or fork-
shaped end portion, whose purpose will be described in
more detail below. Pivot pins 42 seat in corresponding
pivot mount openings 50 in the casing of switch 24.
Base plate 34 rests on movable pin 30. An end portion
44 cooperates with the switch casing to act as a stop
to limit the pivotal motion of actuator 32 in the
direction away from pin 30.
The auxiliary switch actuating mechanism of the
first embodiment of this invention also includes a
locking member or arm, generally designated 52. Re-
ferring to Figures 2A and 2B, the locking member 52
has a central portion 54 which defines a central
openin~ 55 therein. A first arm 56 extends radially
from central portion 54 in a first direction. A
finger 60 and a shoulder 62 are formed at the distal
end of first arm 56. Arm 56 of locking member 52
rides in channel 48 of actuator member 32. A second
arm 58 extends from central opening 54 at an angle to
arm 56. Second arm 5B has a generally J-shaped
configuration. Arm 58 has an intermediate body
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portion 64 and a hooked end porti~n 66, extending from
the distal end of intermediate body portion 64. A
connecting leg portion 68 extends from the proximal
end of the intermediate body portion 64 substantially
at right angles tbereto and connects it to the central
portion 54 substantially at right angles to the first
arm 56. Intermediate portion 64 therefore extends
substantially parallel to the first arm 56.
The locking member 52 is mounted on frame 22 by
means of a pivot pin 70 which passes through opening
55 and corresponding mounting holes in the frame 22.
Pin 70 also mounts contact arm 18 to the frame 22. PiD
70 thus defines an axis about which both contact arm
18 and locking arm 52 p;vot. tMounting pin 70 corre-
sponds to the mounting pin 83 shown in Figs. 1 and 2
of the aforementioned '412 application.) A bias
spring 72 also m~unts on piD 70 over a spring bushing
lnot shown) and engages arm 56 to bias the locking
member 52 toward a normally locked position. That is,
spring 72 urges member 52 to rotate counterclockwise
in Fig. 1. A second spring (not shown) is coaxial with
spring 72, and acts similarly to bias contact arm 18
in the counterclockwise direction, to ensure that the
contacts 7 and 8 are separated when the breaker is
tripped.
Fig. 1 shows a side view of the auxiliary switcb
and swîtch actuator aDd breaker mechanism of this em-
b~diment of the invention with the breaker in the ON
position, i.e. the main contacts 7 and 8 are abutting.
Fig. 4 shows a partly cut-away perspective view of
this breaker iD the ~P~ position. Comparison of these
two figures will make the operation of the breaker of
the invention clear to those of skill in the art.
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When the breaker handle 1~ is moved from the OFF
position to the ON position, that is, to the right in
Fig. 1, the breaker mechanism 14 acts on movable con-
tact arm 18, causing it to pivot about the pivot axis
defined by mounting pin~70, bringing ~he movable con-
tact 7 on arm 18 into engagement with the fixed break-
er contact 8 as shown in Fig. 1. The electrical cir-
cuit through the breaker is then completed and cur-
rent can flow through the breaker in the normal man-
ner. As the movable contact arm 18 pivots under the
action of the breaker mechanism 14, the bottom surface
19 of arm 18 engages the flange 38 of actuator arm 36.
This causes actuator member 32 to pivot about the axis
defined by mounting pins 42 against the spring pres-
sure exerted by the internally sprung contact of the
auxiliary switch, acting through movable pin 30. Con-
tinued movement of actuator 32 causes the inward edge
48a of the slot 48 formed by the bifurcated end shape
of actuator member 32 to slide past shoulder 62 of
locking member 52. Due to the bias of spring 72, urg-
ing member 52 to pivot counterclockwise about pin 70,
shoulder 62 overrides the upper surface of base plate
34 at this point, forming a stop and preventing move-
ment of actuator member 32 in the opposite direction,
i.e. upwardly in Fig. 1. Finger 60 engages the back
edge 48a of the slot 48, limiting the counterclockwise
motion of arm 52. The auxiliary switch is then held
in the actuated position until the shoulder 62 of
locking arm 56 is moved out of engagement with the
actuator member 32.
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~zS~9
Typically, auxiliary swit~h 24 will have three çontact
terminals: a Gommon or "C" terminal ~to whi~h the spring
contaçt is connected), a normally open or "N~O" terminal,
and a normally Glosed or "N/C" terminal. Current flows
through the auxiliary switGh spring GontaGt member between
the common or "C" terminal and either the N~C or NJO
terminal. When the cir~uit breaker is turned ON [closing
the circuit through the main breaker conta~ts), the
actuator member 32 sets the auxiliary switch 24, in the
manner described above, to close a cirGuit between the C
and N/O terminals. This is the N/O state of auxiliary
switGh 24. Operation of the auxiliary switch in the
opposite sense, i.e. suGh that the G terminal is Gonnected
to the N~C terminal when the main breaker GontaGts abut,
is, of Gourse, also within the scope of this invention.
During normal operation of the GirGuit breaker, when the
handle 16 is manually mQved between the ON and OFF
position~, shown respeGtively in Figures 1 and 4, sear pin
20 en~a~es the link members of the breaker meGhanism 14 to
prevent the linkage from Gollapsing. When the handle 16 is
manually moved from the ON to the OFF position by an
operator under normal operating conditions, the link
mechanism 14 remains locked by the engagement of the sear
pin 20. As the handle pivots from the ON to the OFF
position, sear pin 20 follows a first path of travel which
keeps the sear pin 20 clear of contact with the arm $~ of
locking member 52. As movable contact arm 18 pivots
upwardly about pivot pin 70, moving movable contaGt
7 out of engagement with the fixed contaGt 8, and
thereby opening the main cirGuit, the forGe exerted by
arm lR on pin 80 of auxiliary switGh 24 through arm 36 of
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actuator member 32 is released'. In the absence of any
restraint on actuator 32, the bias on pin 30 exerted
by the internal spring of switch 24 would cause the
internal contact to be returned to the N/C position.
This is prevented, however, by the' action of the
locking member 52. The shoulder 62 of arm 56 acts as
a stop against base plate 34 of actuator member 32 to
restrain the upward movement of actuator member 32 due
to the biasing force exerted thereon by the auxiliary
switch internal contact t~rough movable pin 30.
Therefore, when the breaker is manually opened, the
contacts of auxiliary switch 24 remain in the N/O
state.
By comparison, when the breaker is tr'ipped by an
overcurrent through the main circuit, the armature 4
strikes the sear pin 20, causing it to collapse the
linkage mechanism in a known manner, and opening the
main circuit. The collapsing- action of the linkage
mechanism causes the sear pin 20 to move in a second
path of travel which brings it into contact with the
second arm 58 of locking member 52. Continued move-
ment of sear pin 20 causes locking member 52 to rotate
about pivot pin 70, against the bias provided by
spring 72. This, in turn, causes shoulder 62 to be
disengaged from plate 34, releasing the actuator
member 32. Movable pin 30 can then be moved outwardly
by the internally biased spring contact, so that the
auxiliary switch 24 switches from the N/O state to the
N/C state. An alarm circuit connected between the C
and N/C terminals of the auxiliary switch 24 thus will
be closed. This can be used to provide a remote
indication of the tripped breaker condition.
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Figures 5-8 show a second embodiment of the
auxiliary switch mechanism of the present invention.
Elements which are identical to those of the first
embodiment retain the same reference numbers. Ele-
ments which are modified forms of those shown in the
first embodiment are represented by primed reference
numbers, and totally new elements are shown with new
reference numbers.
Fig. 5 shows a side view of the breaker mechanism
of the second embodiment .with the main contacts
closed, and Fig. 8 shows a cutaway perspective view of
the second embodiment with the main contacts open.
Fig. 8 shows the auxiliary switch in the N/O state,
that is, after a manual opening of the main contacts.
Except as discussed below, the operation of the
breaker in the second emboaiment is the same as that
in the first embodiment.
Referring to Figure 5, the movable pin 30 is under
the immediate control of an actuator member 80. As
shown in Figures 7A and 7B, actuator member 80 com-
prises a base portion 82 and an arm 84. Arm 84 ex-
tends upwardly from the base portion 82. The base
portion 82 further has a box-shaped housing for re-
ceiving locking member 52'. A recess 92 in housing 90
terminates in a floor portion 94 and a raised edge
portion 96. A lower wall portion 95 joins floor por-
tion 94 and raised edge portion 96, and a back wall
portion 97 joins raised edge portion 96 with the peri-
phery of recess 92. A step is thus formed at the
junction of the bottom and back walls of the recess
92. A shim 98 may be attached to the outer bottom
surface of the actuator member 80, where it engages
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the movable pin 30. The shim 98 can be used as needed
to compensate for varying tolerances due to the fit
of the auxiliary switch in the casing, or to increase
the upward force exerted on the actuator member 80 by
the spring biased movable pin 30.
A pair of pivot pins 86a and 86b extend laterally
outward from the base portion 82 of the actuator member
80 near an end 88 thereof opposite the end from which
the arm 84 extends. Pivot pins 86a and 86b seat in
corresponding pivot mounting openings in breaker casing
12.
This embodiment has the advantage that the actuator
member 80 is formed of a non-conductive material.
Locating the leg 56' of locking member 52' in the recess
92 of actuator member 80 effectively increases the creepage
and clearance distance between the conductive leg 56'
and the exterior of the case. The construction of the
second embodiment satisfies the safety standards of
the International Electro Technical Commission (IEC)
and the West German Verband Deutscher Elektrotechniker
e.V. (VDE) codes.
Figures 6A and 6B show the locking member 52' of
the second embodiment. Locking member 52' has an arm
56' which terminates at a s~uare end 63; whereas locking
member 52 terminates in finger 60 and shoulder 62.
The second embodiment of the invention operates
generally similarly to the first, with some differences
as noted below: When the movable contact arm 18 is
pivoted under the action of the breaker mechanism 14
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during resetting of the breaker, the bottom surface
19 of arm 18 abuttingly engages arm portion 84 of actuator
member 80. This causes the actuator member 80 to pivot
about the axis defined by mounting pins 86a and 86b
against the spring bias acting through movable pin 30.
When actuator 80 is pivoted clockwise about the axis
defined by pins 86a and 86b during resetting of the
breaker, the end 63 of the locking member 52' slides
upwardly along wall portion 95 connecting the floor
94 of recess 92 in actuator 80 toward the raised edge
portion 96. When, the end 63 reaches the level of raised
edge portion 96 of locking
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arm housing RQ, ~ias sprin~ 72 urges member $2' to pivot
about pin 70, so that end 63 overrides the raised edge
portion 96, to abut the baGk wall ~7 of recess 92, as shown
in Figure 5. This forms a stop against movement of
actuator member 80 in the opposite direction, i.e. prevents
it from pivoting upwardly if the breaker ~ontacts are
opened normally. This locking action caused by the
interaction between the s~uared end 63 and the raised edge
portion ~6 Gorresponds to the interaçtion between the
fin~er 60 and shoulder 62 of locking arm 52 and the
bifurcated end portion of actuator member 32 in the first
embodiment of the invention.
As in the first embodiment, when the breaker is tripped
by an overcurrent through the main circuit, sear pin 20 is
pivoted by arm 46 to strike arm 58' of locking member 52'
and rotate member S2' clockwise about the pivot pin 70
a~ainst the a~tion of bias s~ring 72. This, in turn,
causeR end 63 of the locking arm 52' to be disen~aged from
raised edge portion 96 of recess ~2. This releases the
actuator member 80; as the moving contact arm 18 has
already moved out of engagement with arm 84, the bias on
movable pin 30 urges actuator 80 upwardly. This allows
switch 24 to switch from the N~0 state to the N~C state.
When the breaker is manually turned of f, the sear pin 20
travels in a path so that it does not strike the locking
member 52'. Hence the auxiliary switch is not disturbed,
and it remains in its N~0 state.
The auxilary switch actuator meGhanism of this
invention is composed of only three essential parts:
the actuator member 32 or 8Q, the loc~ing member 5~ or
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52', and the bias spring 72. The actuator member 32
or 80 and locking member 52 or 52' are mountable to
almost any standard breaker mechanism. Since the two
parts are mounted in an interlocking arrangement,
there is no need to manufacture them to close tole-
rance. By virtue of their interlocking arrangement,
they provide essentially trouble-free, reliable opera-
tion over the normal life of the breaker. Further,
the locking member 52 or 52' pivots on the same frame
as does the contact arm, Eesulting in a simplified
construction over known devices.
The invention may be embodied in other s~ecific
forms without departing from the spirit or essential
characteristics thereof. The present embodiments are
therefore to be considered in all respects as illus-
trative and not restrictive, the scope of the inven-
tion being indicated by the appended claims rather
than by the foregoing description, and all changes
j which come within the meaning and range of equivalency
¦ of the claims are therefore intended to be embraced
therein.
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