CIRCUIT BREAKER TRIP INDICATION DEVICE

DISJONCTEUR AVEC DISPOSITIF INDICATEUR

English Abstract

Abstract
A moulded case circuit breaker is provided with a trip
detector by enclosing a microswitch within the moulded case but
out of the path of the operating mechanism. An L shaped
operator for the microswitch has one leg which operates the
microswitch and the other leg in the path of the trip mechanism
of the breaker so that the microswitch is operated when the
breaker is tripped.

Claims

4
CLAIMS:
1. A moulded case circuit breaker comprising:
(a) a fixed contact mounted on the case;
(b) a movable contact mounted on an arm;
(c) an operator connected said arm for moving said
movable contact from an "open" to "closed" position;
(d) a toggle mechanism including a cradle latched
by a trip mechanism and holding said moving contact in said
"closed" position when said cradle is latched and releasing
said contact to said "open" position when said cradle is
unlatched;
(e) a switch mounted wholly within the moulded
case of said breaker including an operator arranged in the
path of said cradle and contacted by said cradle when said
cradle moves to its unlatched position;
(f) leads extending from said switch through said
casing for connection to a switch condition indicating device.
2. A moulded case circuit breaker as claimed in
claim 1 wherein said cradle is pivotally mounted at one of
its ends and is latched by a trip mechanism at its other end
and is resiliently connected to said arm.
3 A moulded case circuit breaker as claimed in
claim 2 wherein said cradle includes an offset producing a
flat portion transverse to the plane of rotation of said
cradle about its pivotal mounting.
4. A moulded case circuit breaker as claimed in
claim 3 wherein said flat portion of said cradle contacts
said operator when said cradle rotates about its pivotal
mounting into its unlatched position.

5
5. A moulded case circuit breaker as claimed
in claim 1 or 4 wherein said switch is mounted to one side
of the plane of rotation of said cradle and said operator
is "L" shaped with one leg of the "L" projecting into the
plane of rotation of said cradle.
6. A moulded case breaker as claimed in claim 1
or 4 in which said switch is a microswitch.
7. A moulded case breaker as claimed in claim 1
or 4 in which said switch includes normally open and normally
closed contacts.
8. A moulded case breaker as claimed in claim 1
or 4 in which said leads are connected to indicator lamps
to indicate the condition of said breaker.
9. A moulded case circuit breaker including a
trip detector comprising a microswitch within the moulded
case of said breaker and out of the path of the operating
portions of said breaker, an operator for said microswitch
including a portion which projects into the operating path
of the trip mechanism of said breaker and operates said
microswitch when engaged by said trip mechanism.

Description

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CIRCUIT BREAKER TRIP INDICATION DEVICE
BACKGROUND OF THE INVENTION
This invention relates generally to improvements in
electrical circuit breakers of the moulded case type and more
particularly to an arrangement for indicating tripping or a
tripped condition of such a circuit breaker.
.~oulded circuit breakers are well known and typical of
such a circuit breaker is the breaker illustrated and claimed in
Canadian Patent No. 1,125,856 issued 82/06/15. The circuit
breaker as illustrated in the above patent and generally well
known, consists of a movable contact mounted on a movable arm
and a rigidly mounted stationary contact. The movable arm is
normally rotated between a closed and open position by means of
a handle. The operating linkage which connects the handle to
the movable contact is a collapsible to~gle assembly. ~n
electrothermalmagnetic device in the breaker responds to pre-
determined electrical conditions and permits the toggle assembly
to collapse and the contacts to trip open.
When such toggle mechanism is collapsed and the breaker
is in the tripped position it is desirable, in some circumstances,
that a signal be provided at a remote location indicating that
the breaker has been tripped. Such remote indication of a
tripped condition has been provided in the past in large circuit
breakers and also has been provided in small circuit breakers by
means of separate add-on devices which are associated with the
circuit breaker.
BRIEF SUMMARY OF THE INVENTION
The present invention applies to a circuit breaker of the
type disclosed in Canadian Patent No. 1,125,~56 and provides an
indication of the tripped condition of the breaker without
additional equipment external of the breaker and without
modification of the normal circuit breaker enclosure.
In accordance with the present invention, these objects
are attained by includin~, within the moulded case of the breaker,
a small microswitch which intercepts a portion of the cradle when

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the cradle is in a tripped condition.
A clearer understanding of our invention may be had from
a consideration of the following description and drawings in
which:
Figure 1 shows a circuit breaker incorporating the
lnvention with the circuit breaker in the latched position.
Figure 2 shows the same circuit breaker shown in a
tripped condition.
Considering first Figure 1, there is shown a circuit
breaker comprising a moulded plastic enclosure 4, a handle 5,
fixed contact 6, movable contact 7 mounted on an arm 8 which in
turn is pivoted on handle 5. The toggle mechanism for the breaker
includes the cradle 9 and the arm 8 which are resiliently connected
one to the other by spring 11. Cradle 9 is normally restrained
from rotation about its pivot 10 by the engagement with latch 12
which is a portion of the electromechanical trip mechanism.
Details of the trip mechanism and the to~gle will not be provided
since they are well known in the art and are disclosed, in
particular, in Canadian Patent No. 1,125,856. A microswitch 13
is mounted in a cavity in the moulded housing of the breaker in
such a manner as not to interfer with any operating portion of
the breaker. An arm 14 on the microswitch is arranged in the path
of the flat portion 17 formed by the offset of the cradle 9. As
will be seen in Figure 2, in the tripped position the cradle 9 is
released from the latch 12 and rotates downwards about its pivot
10 and the flat portion 17 engayes the arm 14 causing the micro-
switch 13 to be actuated. Suitable leads, 15, 16 and 18 for
normally open and/or closed configurations extend from the micro-
switch out through a suitable aperture in the housing and may be
used to actuate any indicator such as a lamp or alarm which will
indicate the tripping of the breaker.
As will be seen from Figure 2, the microswitch 13 is
operated only when the cradle 9 is rotated and therefore is
actuated only when the breaker is tripped. When the breaker is
manually operated from an on to an off position, the cradle remains
in its counter clockwise rotated position, that is in its latched
position.

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Because of the dimens:ions and the location of the
microswitch, it is practical to include the microswitch within
the moulded case of the breaker and thus the breaker can be
inserted in its normal location in a panel board or other
enclosure which has been designed for standard breakers.
While the invention has been illustrated in conjunction
with a par.ticular type of moulded case circuit breaker, it will
be evident that it is applicable to any moulded case breaker
which is tripped by means of movement of a member similar to
cradle 9 and in which sufficient space is available within the
enclosure to permit mounting of the microswitch.