Note: Descriptions are shown in the official language in which they were submitted.
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CIRCUIT BREAKER AUXILIARY SWITCH APPARATUS
BACKGROUND OF THE INVF.NTION
The present invention relates to accessory
apparatus for circuit breakers and particularly to
auxiliary switch apparatus for residential, molded
case circuit breakers.
Commonly assigned U.S. Patents Nos . 3,256,407
to Bandt dated June 14, 1966 and 3,973,230 to Ciarcia
et al dated August 3, 1976, disclose residential molded
case circuit breakers to which have been adapted
auxiliary switch apparatus of the so-called "bell
alarm" type. In accordance with this type of
auxiliary switch, a change in switch condition is
effected only when the circuit breaker is automatically
tripped open, but not when the circuit breaker is
opened manually via its external operating handle.
Thus a bell alarm switch is utilized to control an
external alarm circuit operating to alert personnel
when a circuit breaker has tripped automatically in
response to an abnormal circuit condition, e.g., over-
current, ground fault and undervoltage, on the ;;
protected circuit; conditions requiring correctivemeasures. Since manual opening of a circuit breaker
is normally not intended to call for corrective
measures, no such alarm or signal is desired.
In certain applications however, it is desired to
alert personnel when a circuit breaker is opened,
regardless of whether it is tripped open or manually
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opened. The straight~orward approach to achieving
this ~unction is to mechanically translate the opening
movement of the breaker contacts into actuation of an
auxiliary switch. In the case of residential molaed case
circuit breakers however, this straightfoxward approach
is difficult to implemen-t structurally.
It is accordingly an object of the present
invention to provide improved auxiliary switch
apparatus operating to produce an auxiliary switch
actuation incident with the opening of a circuit
breaker, regardless of how effected.
An additional object is to provide auxiliary
switch apparatus of the above character which is
compact, simple in construction, and reliable in
operation.
Yet another object is to provide auxiliary switch
apparatus of the above character which can be readily
adapted to small residential, molded case circuit
breakers with minimal modification to the breaker
itself.
Other objects of the invention will in part be
obvious and in part appear hereinafter.
In accordance with the present invention, there is
provided auxiliary switch apparatus of compact
construction capable of being accommodated in a
molded accessory case affixed in side-by-side relation
with one or more residential molded case circuit
breakers. This accessory case can, for example, be
constituted by an empty molded circuit breaker case
o~ the same configuration as that of the circuit
breaker to which it is a~fixed. Alternatively, the
accessory case may be constituted by one compartment
of a molded case with the circuit breaker accommodated
in a second compartmen-t thexeof; the two compartments
being separated by a common wall. In either situation,
the pivotal circuit breaker operating handle mounts a
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pin which extends laterally into the accessory case
through a clearance opening in the wall of walls
separating the two cases. A second pin, carriad by
an internal trip actuating member of the circuit breaker,
also extends laterally in~o the accessory case. An
auxiliary switch, mounted within the accessory case,
has a resilient actuating arm disposed in proximate
relation to the second pin. When the circuit breaker
is tripped, either directly by operation of its own
trip unit or indirectly by operation of the trip unit
of another circuit breaker operatively coupled thereto
by an internal common trip bar ganging their trip
actuating members together, the second pin is
articulated into deflecting engagement with the switch
actuating arm. The auxiliary switch is thus actuated
incident with tripping of the circuit breaker.
To achieve switch actuation incident with manual
opening of the circuit breaker, ~he handle mounted
first pin engages a finger of a rotatably mounted~
handle actuated element incident with pivotal movement
of the handle to its OFF position. The resulting
rotational movement of this element swings a second
finger thereof into engagement with a finger of a
separate, rotatably mounted switch actuating element,
thereby causing a second finger thereof to swing into
actuating enagagment with the switch actuating arm.
Thus, auxiliary switch actuation is achieved incident
with manual switching of a circuit breaker to its OFF
condition, as desired.
The invention accordingly comprises the features
of construction, combination of elements and
arrangement of parts which will be exemplified in the
description hereinafter set foxth, and the scope of the
invention will be indicated in the claims.
For a better understanding of the nature and
objects of the invention, reference should be had to
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the following detailed description taken in conjunction
with the accompanying drawing, in which:
FIGURE l is a side elevational view of the internal
parts of a typical residential molded case circuit
S breaker to which the auxiliary switch appara-tus of the
present invention is adaptable; and
FIGURE 2 is a side elevational view, partially
broken away, of auxiliary switch apparatus constructed
in accordance with the present invention.
Corresponding reference numerals refer to like
parts throughout the several views of the drawing.
FIGURE 1 of the drawing illustrates a typical
residential, molded case circuit breaker to which the
auxiliary switch apparatus of the present invention is
adaptable. This circuit breaker, generally indicated
at lO, may be of the construction disclosed in
commonly assigned U.S. Patent No. 3,464,040 to Powell
dated August 26, 1969. In order to promote a cornplete
understanding of the auxiliary switch apparatus of
the present invention, it is believed desirable to
briefly review the circuit breaker construction of
this patent. Thus as seen in FIGURE 1 herein, a
circuit breaker lO includes a manual operating handle
12 which is pivGtally mounted in a molded circuit
breaker case 14 by means of oppositely extending,
integrally formed hub portions 16. The handle
includes a depending portion 18 to which the upper
end of a movable contact arm 20 is pivotally connected.
A movable contact 22 is affixed to the lower end of
arm 20 for engagement with a stationary contact 24
carried by a depending line strap 26 integrally
formed with terminal jaws 28 adapted for plug-on
electrical contacting engagement with a line stab in
a circuit breaker load center (not shown). A tension
spring (not shown) is connected between movable contact
arm 20 and a cradle 30 which is pivotally mounted at
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one end in the case 14, as indicated at 32.
The cradle is normally retained in its position
shown by a latch 34a in the form of a tab struck from
a depending armature 34 pivotally mounted at its upper
end in the circuit breaker case. A spring 36 biases
the depending portion of the armature to the left,
thus ensuring that the latch is in position to engage
a tip 30a of cradle 30, pursuant to retaining the
breaker operating mechanism in its untripped condition.
Included in the circuit breaker internal circuit
is an elon~ated bimetal 38 which is mounted at its
upper end to the inner end of a load strap 40 extending
outwardly from the case interior to a wire lug 42
facilitating external connection with a load circuit
(not shown). The load strap is affixed to the breaker
case by a screw 43. Completing the circuit breaker
internal circuit, a braid 44 is electrically connected
between movable contact arm 20 and the low0r end of
bimetal 38.
2~ To effect a thermal trip function in response to
`; overload currents, the lower end portion of bimetal
38 deflects to the right as seen in FIGURE 1, and
this movement is communicated to armature 34 via an
armature hook 46. Corresponding rightward movement
of the armature disengages latch 34a from the cradle
tip 30a to unlatch the breaker operating mechanism
` and thus open the breaker contacts 22 and 24.
To accommodate rapid tripping of the circuit breaker
in response to heavy overload or short circuit currents,
an elongated magnetic field piece 50 is mounted at
its upper end to the breaker case and has a lower end
portion of U-shaped cross-section disposed in partially
embracing relation with bimetal 38. With the flow of
` current of heavy overload and short circuit pro-
portions through the bimetal sufficient flux is
d0veloped in this field piece of attract armature 34
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rightward and thus pull latch 34a away from latching
engagement with cradle tip 30a, tripping the circuit
breaker.
In order that the circuit breaker may be tripped
5 externally, for example in response to the tripping
of a companion circuit breaker ganged thereto in a
two or three-pole configuration or in response to a
ground fault condition, a trip actuating member 52
is pivotally mounted at its upper end in the breaker
10 case by means of integrally formed trunions 52a
for pendency in proximate relation with armature 3~.
As more clearly seen in the above-noted u.s. patent
No. 3,464,040, when cradle 30 is released by armature
34, the breaker mechanism spring acts to pivot the
15 cradle in the clockwise direction seen in FIGURE 1
herein, thereby swinging a knee portion 30b thereof
into engagement with a trip actuating member 52.
The trip actuating member is thus pivoted in the
counterclockwise direction, swinging its lower end
20 rightward toward armature 34. To provide internal
common tripping for plural circuit breakers ganged
together in two and three-pole configurations, the
trip actuating members 52 of the ganged circuit
breakers are tied together by a common trip bar r
25 (not shown) which is received in rectangular apertures
52b thereof, seen in FIGURE 1. A detailed disclosure
.` of a typical internal common tripping provision for
single pole breakers ganged together in two and
three-pole configurations may be found in U.S.
Patent No. 3,288,965 - Xlein dated November 29, 1966.
Thus, when one of these ganged circuit breakers trips
in response to overload or short circuit currents
~lowing through its circuit pole, the released cradle
therein impacts against its associated trip actuating
member 52, causing all of the trip actuating members
of the other circuit breakers to be pivoted into
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unlatching engagement with their associated armatures
34. Thus, when one circuit breaker trips, all of
the other circuit breakers are coincidentally tripped.
Trip actuating member 52 is also utili~ed when
5 circuit breaker lO is utilized in a ground fault
circuit interrupting (GFCI) configuration. To this
end, the trip actuating member 52 is operatively
coupled with a trip solenoid acting to swing it into
tripping engagement with armature 34 upon being
10 energized by a ground fault module in responding to
a ~round fault condition on the circuit breaker load
circuit.
To adapt circuit breaker 10 for utilizing the
auxiliary switch apparatus of the present invention
15 seen in FIGURE 2, a first elongated, laterally
e~tending pin 58 is mounted by the depending portion
18 of handle 12, and a second elongated, laterally
extending pin 60 is mounted by trip actuating member
52 adjacent its lower end. Turning to FIGURE 2, it r
2Q is seen that pin 58 extends through an arcuate
opening 62a provided in the wall or walls 62
separating the circuit breaker case from an
auxiliary case 63 affixed thereto. Similarly, pin
60 extends into the accessory case through an opening
25 62b in the case separating wall. Mounted in the
accessory case is an auxiliary switch 64 having an
actuating pin 64a. This switch in turn mounts one
end of an elongated, flexible actuating arm 66
disposed in actuating relation with actuating pin
30 64a. To take up the displacement between the normal
position of pin 60 and the unactuated disposition
of actuating arm 66 and to promote electrical
isolation between the breaker parts and the switch
actuating arm, an insulative spacer sleeve 60a is
35 fitted on pin 60. It i5 seen that when circuit breaker
10 is tripped, either by operation of its own trip
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unit, the trip unit of a companion circuit breaker,
or the firing of a ground fault trip solenoid,
trip actuating member 52 is swung in the counter-
clockwise direction, causing its pin 60 to swi~g
5 rightward as seen in FIGURES 1 and 2. Switch
actuating arm 66 is thus deflected to its phantom
line position as seen in FIGURE 2, depressing
actuating pin 64a to achieve actuation of auxiliary
switch 64. This switch actuation is manifested in an
10 external alarm circuit into which the auxiliary switch
is wired via leads 70 emanating from the accessor~
case 64.
In order to translate th~ operation of circuit
breaker handle 12 from its ON position seen in
15 FIGURE 2 to its OFF position seen in FIGURE 1 into
actuating of auxiliary switch 64, wall 62 mounts a
~ post 72 on which is rotatably mounted a handle
- actuated element 74 This element carries a first
finger 74a which extends upwardly into engaginy
20 relation with pin 58 carried by operating handle 12. r
; Thus, when the handle i5 pivoted in the clockwise
direction to its OFF position, pin 58 is swung to
the left, engaging finger 74a to induce counte~-
clockwise rotation of element 74. Wall 62 additionally
25 mounts a second pivot post 76 on which is rotatably
mounted a switch actuating element 78. This element
carries a finger 78c which extends radially outward
into engaging relation with a finger 74b carried by
switch actuated element 78. It is thus seen that
30 when handle actuated element 74 is rotated in the
counterclockwise direction in response to the
-~ pivoting of the operating handle 12 to its OFF
position, finger 74b thereof picks up finger 78c of
switch actuating element 78 to induce clockwise
35 ro-tation thereof. As a consequence, a second finger
78b of the switch actuating element is swung into
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engagement with actuating arm 66, deflecting it to its
phantom line position to effect actuation of auxiliary
switch 64. When operating handle is pivoted back to
its ON position, the resiliency of switch actuating
arm 66 returns the elements 74 and 78 to their angular
positions shown, as determined by the position of
pin 58.
An additional point to be noted is that when the
breaker is tripped, causing pin 60 to effect auxiliary
switch actuation, handle 12 moves to an intermediate
trip indicating position. To reset the breaker
mechanism, i.e., elevate cradle tip 30a back into
latching engagement with armature latch 34a, handle
12 is pivoted to its OFF position. In the resetting
process, cradle knee 30b releases trip actuating
member 52 and thus pin 60 swings away from switch
deactuation is not permitted, since, with handle 12
assuming its OFF position, pin 58, via elements 74
and 78, will have swung finger 78b into switch actuation
sustaining engagement with arm 66.
It is noted that handle actuated element 74 and
switch actuating element 78 are indentically
constructed and fully interchang~able for manufacturing
and assemhly economies. When the element is mounted
on post 72, its finger 74c serves no function. On
the other hand, when the element is mounted in post
76, finger 78a has no useful purpose. As illustrated,
auxiliary switch 64 may comprise two switch units
actuated in single throw, double pole fashion with
the individual switches either of the normally open
or normally closed types.
It will thus be seen that the objects set forth
above, among those made apparent in the preceding
description, are efficiently attained and, since
certain changes may be made in the above construction
without departing from the scope of the invention, it
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it is intended that all matter contained in the
above description or shown in the accompanying
drawings shall be interpreted as illustrative and
not in a limiting sense.
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