05-EDP-320
CROSSBAR ASSIST MECHANISM AND ELECTRICAL SWITCHING
APPARATUS EMPLOYING THE SAME
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates generally to electrical switching apparatus and, more
particularly, to a crossbar assist mechanism for electrical switching apparatus, such as a
circuit breaker. The invention also relates to electrical switching apparatus having a
crossbar assist mechanism.
Background Information
Electrical switching apparatus, such as circuit breakers, provide protection
for electrical systems from electrical fault conditions such as, for example, current
overloads, short circuits, and other fault conditions. Typically, circuit breakers include a
spring powered operating mechanism which opens electrical contacts to interrupt the
current through the conductors of an electrical system in response to abnormal
conditions.
The electrical contacts generally comprise one or more movable contacts
and one or more corresponding stationary contacts. Each pair of separable contacts is
electrically connected, in series, between corresponding line and load terminals which are
typically positioned at opposite ends of the circuit breaker. More specifically, each
movable contact is disposed at or about a first end of a corresponding movable contact
arm, which is part of a movable contact assembly. The movable contact arm is pivotably
coupled, at or about its second end, to a crossbar of the operating mechanism. A suitable
shunt (e.g., without limitation, flexible conductor) electrically connects the movable
contact assembly to a load conductor, for example, by way of a clinch joint. Typically, a
clinch joint comprises two thicknesses of material {e.g., without limitation, metal) joined,
for example, by extruding one piece into the other using a punch and die to form a
swaged joint in such a way that the two pieces cannot be subsequently separated. The
operating mechanism controls the movable contact arm to pivot the movable contact into
and out of electrical contact with the corresponding stationary contact. The crossbar
carries the movable contact arms for all of the poles of the circuit breaker, and allows for
simultaneous opening and closing of the contacts in all of the poles.
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Manual opening and closing of the contacts is accomplished by way of an
operating handle coupled to the crossbar. Specifically, the operating handle, which is
disposed on the outside of the circuit breaker housing, is manipulated from an OFF
position to an ON position in order to close the contacts. The contacts can also be tripped
automatically by a trip unit in response to abnormal conditions. The trip unit includes,
for example, a pivotable trip bar which latches the operating mechanism. Upon detection
of an overcurrent condition, the trip unit rotates the trip bar to unlatch the operating
mechanism which, in turn, pivots the crossbar and opens the contacts of all of the poles.
Typically, the handle position corresponding to the tripped position is between the ON
and OFF positions.
Certain circumstances can make it difficult for a user to manually move
the operating handle from the OFF position to the ON position. For example, electrical
current flowing through the circuit breaker generates heat which can adversely affect
certain components of the circuit breaker operating mechanism, for example, by making
them swell or enlarge. Thus, when the circuit breaker is hot, friction among the operating
mechanism components increases, making it difficult for a user to manually turn the
circuit breaker from the OFF position to the ON position.
There is a need, therefore, for facilitating operation of the circuit breaker
from the OFF position to the ON position.
There is, therefore, room for improvement in electrical switching
apparatus, and in mechanisms for facilitating the operation of the electrical switching
apparatus operating mechanism.
SUMMARY OF THE INVENTION
These needs and others are met by embodiments of the invention, which
are directed to a crossbar assist mechanism for an electrical switching apparatus.
Through use of a unique biasing element, the crossbar assist mechanism facilitates
movement of the circuit breaker operating handle from the OFF position toward the ON
position.
As one aspect of the invention, a crossbar assist mechanism is provided
for an electrical switching apparatus. The electrical switching apparatus includes a
housing, a first conductor, a second conductor, a stationary contact, a movable contact,
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and an operating mechanism. The stationary contact is electrically connected to the first
conductor. The operating mechanism includes a crossbar, a carrier having a first end
coupled to the crossbar and a second end, and a movable contact arm. The movable
contact arm is pivotably cooperable with the second end of the carrier. The movable
contact is disposed on the movable contact arm, and the crossbar is structured to move
the carrier and the movable contact arm, thereby moving the movable contact disposed on
the movable contact arm into and out of electrical contact with the stationary contact.
The crossbar assist mechanism comprises: an electrically conductive member structured
to electrically interconnect the movable contact arm of the operating mechanism of the
electrical switching apparatus and the second conductor; and a biasing member structured
to be disposed between the crossbar of the operating mechanism of the electrical
switching apparatus and the electrically conductive member, and further structured to
bias the crossbar of the operating mechanism from a first position corresponding to the
movable contact and the stationary contact being separated, toward a second position
corresponding to the movable contact being in electrical contact with the stationary
contact.
The biasing member may comprise a spring, such as a conical spring,
which includes a first end and a second end, wherein the first end of the spring is
structured to bias the crossbar of the operating mechanism of the electrical switching
apparatus, and the second end of the spring is coupled to the electrically conductive
member. The electrically conductive member may include an aperture structured to
receive and secure the second end of the spring. The spring may also be fastened to the
electrically conductive member in order to maintain the position of the spring within the
aperture of the electrically conductive member. The electrically conductive member may
comprise a clinch joint including a cast member having a first end and a second end,
wherein the carrier and the movable contact arm of the operating mechanism of the
electrical switching apparatus are structured to be pivotably and electrically coupled at or
about the first end of the cast member, and the second end of the cast member is
electrically coupled to the load conductor. The cast member may further comprise a top,
wherein the aperture of the cast member comprises an elongated slot in the top of the cast
member, wherein the second end of the spring includes at least one coil, and wherein the
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at least one coil of the second end of the spring is disposed within the elongated slot of
the cast member.
As another aspect of the invention, an electrical switching apparatus
comprises: a housing; separable contacts housed by the housing, the separable contacts
comprising at least one movable contact and at least one stationary contact; an operating
mechanism comprising a crossbar, at least one carrier, and at least one movable contact
arm, each of the at least one movable contact being disposed on a corresponding one of
the at least one movable contact arm, the at least one carrier having a first end coupled to
the crossbar and a second end pivotably cooperable with the corresponding one of the at
least one movable contact arm, the operating mechanism moving the at least one carrier
and the corresponding one of the corresponding one of the at least one movable contact
arm, thereby moving the at least one movable contact disposed on the at least one
movable contact arm into and out of electrical contact with a corresponding one of the at
least one stationary contact; and at least one crossbar assist mechanism, each of the at
least one crossbar assist mechanism comprising: an electrically conductive member, the
electrically conductive member being electrically connected to the at least one carrier and
the corresponding one of the at least one movable contact arm of the operating
mechanism, and a biasing member disposed between the crossbar of the operating
mechanism and the electrically conductive member, in order to bias the crossbar of the
operating mechanism from a first position corresponding to the at least one movable
contact and the corresponding one of the at least one stationary contact being separated,
toward a second position corresponding to the at least one movable contact being in
electrical contact with the corresponding one of the at least one stationary contact.
The electrical switching apparatus may be a circuit breaker having a
plurality of poles, wherein each of the poles of the circuit breaker comprises a single
carrier coupled at or about its first end to the crossbar of the operating mechanism, a
single movable contact arm pivotably cooperable with the second end of the single
carrier, a single movable contact disposed on the single movable contact arm, and a
single corresponding stationary contact, and wherein the at least one crossbar assist
mechanism comprises a separate crossbar assist mechanism for each of the poles of the
circuit breaker.
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The operating mechanism may further comprise an operating handle
having a first end accessible from the exterior of the housing of the circuit breaker, and a
second end coupled to the crossbar of the operating mechanism. The operating handle
may be operable among an OFF position corresponding to the first position of the
operating mechanism, and an ON position corresponding to the second position of the
operating mechanism, wherein the crossbar assist mechanism facilitates movement of the
operating handle from the OFF position toward the ON position.
BRIEF DESCRIPTION OF THE DRAWINGS
A full understanding of the invention can be gained from the following
description of the preferred embodiments when read in conjunction with the
accompanying drawings in which:
Figure 1 is a side elevational view of a circuit breaker and crossbar assist
mechanism in accordance with an embodiment of the invention, with the circuit breaker
housing shown in simplified form, with a portion of one arc chute removed to show the -
separable contacts, and with the circuit breaker operating handle shown in the ON
position;
Figure 2 is an isometric view of the molded case circuit breaker of Figure
1 with the circuit breaker housing removed to show the three separate crossbar assist
mechanisms for the three poles of the circuit breaker, and modified to show the circuit
breaker operating handle in the OFF position;
Figure 3 is an isometric view of the biasing element for the crossbar assist
mechanism of Figure 1; and
Figure 4 is an isometric view of the crossbar assist mechanism of Figure 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
For purposes of illustration, various embodiments of the invention will be
shown and described as applied to the operating mechanism of a three-pole circuit
breaker, although it will become apparent that they could also be applied to bias one or
more components of the operating mechanism of any known or suitable electrical
switching apparatus (e.g., without limitation, circuit switching devices and circuit
interrupters such as circuit breakers, contactors, motor starters, motor controllers and
other load controllers) having any number of poles.
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Directional phrases used herein, such as, for example, left, right,
clockwise, counterclockwise and derivatives thereof, relate to the orientation of the
elements shown in the drawings and are not limiting upon the claims unless expressly
recited therein.
As employed herein, the statement that two or more parts are "coupled"
together shall mean that the parts are joined together either directly or joined through one
or more intermediate parts.
As employed herein, the term "number" shall mean one or an integer
greater than one (i.e., a plurality).
Figure 1 shows a molded case circuit breaker 2 employing a crossbar
assist mechanism 100. The circuit breaker 2 includes a housing 4 (shown in simplified
form in phantom line drawing), a first conductor 6, a second conductor 8, separable
contacts 10,12 disposed between the first and second conductors 6, 8, and an operating
mechanism 14.
As best shown in Figure 2, the separable contacts comprise pairs of
movable and stationary contacts 10, 12, which are electrically connected, in series,
between the first conductor which, in the example shown, is a line conductor 6, and the
second conductor which, in the example shown, is a load conductor 8. Thus, each of the
stationary contacts 12 is electrically connected to a corresponding line conductor 6. In
Figure 2, the circuit breaker 2 is shown with the housing 4 (Figure 1) removed to clearly
show internal structures. Specifically, the circuit breaker 2 includes three poles 26,28,
30, each having its own corresponding line conductor 6 (two line conductors 6 are
shown), load conductor 8, and pair of separable contacts 10,12 (as shown with pole 26).
Each pole 26,28, 30 further includes a separate crossbar assist mechanism 100. It will,
however, be appreciated that the circuit breaker 2 could alternatively include any suitable
number of poles, with any suitable number of crossbar assist mechanisms 100 wherein
the number of crossbar assist mechanisms 100 could be the same as or different than the
number of poles of the circuit breaker.
Referring to Figures 1 and 2, it will be appreciated that the operating
mechanism 14 of the circuit breaker 2 includes a crossbar 16, at least one carrier 18, and
at least one movable contact arm 24. As best shown in Figure 2, the operating
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mechanism 14 of the example three-pole circuit breaker 2 includes three carriers 18, each
having a corresponding movable contact arm 24. The movable contact 10 is disposed at
or about one end of the movable contact arm 24, as shown. The carrier 18 has a first end
20 coupled to the crossbar 16, and a second end 22 which is pivotably cooperable with
the movable contact arm 24. Specifically, the movable contact arm 24 includes a pivot
pin 25 which is pivotable into and out of engagement with a corresponding cradle 27
proximate the first end 22 of carrier 18, when the carrier 18 moves. The carrier 18 pivots
clockwise and counterclockwise about a pivot 29, as indicated by directional arrow 31 of
Figure 1. In the example of Figures 1 and 2, the crossbar 16 pivots with the carrier 18
within the confines of crossbar opening 19 of bracket 21 of the circuit breaker 2.
Accordingly, the operating mechanism 14 moves the carriers 18 and the corresponding
movable contact arms 24, thereby moving the movable contacts 10 disposed on the
corresponding movable contact arms 24 into and out of electrical contact with the
corresponding stationary contacts 12.
In Figure 2, the operating mechanism 14 is shown in a first position
corresponding to the movable contact 10 being separated from its corresponding
stationary contact 12 for each pair of separable contacts 10,12. In this position, the
circuit breaker 2 is OFF. Conversely, Figure 1 shows the movable and stationary
contacts 10,12 being in electrical contact with one another, corresponding to the second
position of the operating mechanism 14, and the ON position of the circuit breaker 2.
The operating mechanism 14 of the circuit breaker 2 further includes an operating handle
32 having a first end 34 which is accessible from the exterior of the housing 4 of the
circuit breaker 2, and which is operable among an OFF position (Figure 2), an ON
position (Figure 1), and also a tripped position (show in phantom line drawing in Figure
1). The tripped position corresponds to the separable contacts 10,12 (shown being
tripped open in phantom line drawing in Figure 1) in response to an electrical fault
condition (e.g., without limitation, current overloads; short circuits; abnormal voltage
conditions; other fault conditions). As shown, the tripped position of the example circuit
breaker operating handle 32 is between the ON position of Figure 1, and the OFF position
of Figure 2. It will, however, be appreciated that the tripped position of the operating
handle 32 could alternatively be shared with the OFF position of the operating handle 32,
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without departing from the scope of the invention. The second end 36 of the operating
handle 32 is coupled to the carrier 18 of the circuit breaker operating mechanism 14.
The crossbar assist mechanism 100, three of which are shown in the three-
pole circuit breaker 2 of Figure 2, facilitates movement of the operating handle 32 from
the OFF position (Figure 2) toward the ON position (Figure 1). Specifically, each
crossbar assist mechanism 100 includes an electrically conductive member 102 which is
structured to electrically interconnect the movable contact arm 24 (partially shown in
hidden line drawing in Figure 1) of the circuit breaker operating mechanism 14 and the
load conductor 8. A biasing member, such as the conical spring 104 shown, is disposed
between the crossbar 16 of the circuit breaker operating mechanism 14 and the
electrically conductive member 102. The conical spring 104 includes a first end 106 and
a second end 108 (Figures 1, 3, and 4). The first end 106 of the conical spring 104 biases
the crossbar 16 in the direction generally indicated by arrow 17 of Figure 1, which shows
the crossbar 16 after having already been engaged and biased by the conical spring 104.
In other words, the conical spring 104 is compressed substantially flat when the crossbar
16 of the circuit breaker operating mechanism 14 is disposed in the first position (i.e., the
circuit breaker operating handle 32 is in the OFF position) of Figure 2. Then, in response
to partial movement of the operating mechanism 14 such as, for example, manual
manipulation of the circuit breaker operating handle 32 from the OFF position of Figure 2
towards the ON position (corresponding to the second position of operating mechanism
14) of Figure 1, the conical spring 104 provides a spring force to the crossbar 16 in order
to facilitate continued motion of crossbar 16, carrier 18, movable contact arm 24, and the
operating mechanism 14 generally, to the second or ON position (Figure 1). It will,
however, be appreciated that any known or suitable biasing member could be employed
in any number and configuration other than, or in addition to the conical spring 104
which is shown and described. For example and without limitation, a leaf spring (not
shown) or one or more Belleville washers (not shown) could be employed to provide the
desired biasing force.
As shown in Figure 3, the first end 106 of conical spring 104 has a first
diameter 107, and the second end 108 of the conical spring 104 has a second diameter
109, wherein the first diameter 107 of the first end 106 is smaller than the second
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diameter 109 of second end 108. It is this structure which permits the conical spring 104
to compress substantially flat when the circuit breaker operating mechanism 14 is in the
first position of Figure 2, as previously discussed. The first end 106 of conical spring 104
further includes at least one coil 122. The coil 122 of the first end 106 has a substantially
flat exterior surface 126, as shown. The substantially flat exterior surface 126 functions
to provide substantially flush engagement with the crossbar 16 of the circuit breaker
operating mechanism 14 when the operating mechanism 14 is in the first position of
Figure 2.
Continuing to refer to Figure 3 and also to Figure 4, it will be appreciated
that the second end 108 of conical spring 104 also includes at least one coil 124. The coil
124 of the second end 108 of the conical spring 104 is coupled to the electrically
conductive member 102 (Figure 4). More specifically, the electrically conductive
member 102 comprises a clinch joint 112 which, in the example of Figure 4, includes a
cast member 114. The cast member 114 includes a first end 116, and a second end 118.
Referring back briefly to Figure 1, it will be appreciated that the carrier 18 and movable
contact arm 24 of the circuit breaker operating mechanism 14 are pivotable and are
electrically coupled at or about the first end 116 of the cast member 114 by pivot 29. The
second end 118 of the cast member 114 is electrically coupled to the load conductor 8.
As best shown in Figure 4, the cast member 114 also includes a top 120
which includes an aperture, such as the elongated slot 110, shown. The second end 108
of the conical spring 104 and, in particular, the coil 124 of the second 108 is disposed
within the elongated slot 110 of the cast member 114. More specifically, the coil 124 of
the second end 108 of conical spring 104 slides into the elongated slot 110, which is
preferably cast in the top 120 of the cast member 114. To maintain the position of the
conical spring 104 within the elongated slot 110, the conical spring 104 is fastened to the
cast member 114 using any known or suitable fastening mechanism or process. For
example, and without limitation, the conical spring 104 in the example of Figure 4, is
staked (i.e., the edges of the elongated slot 110 are compressed or deformed (not
expressly shown) over coil 124 of second end 108 of the spring 104) to secure it to the
top 120 of cast member 114.
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Accordingly, the crossbar assist mechanism 100 provides a novel and
unique improvement for facilitating movement of the operating mechanism 14 of
electrical switching apparatus 2. Specifically, the biasing element, such as the
aforementioned conical spring 104, biases the crossbar 16 of the operating mechanism 14
thereby facilitating movement (i.e., toggle of the operating mechanism 14) from the first
position to the second position. In this manner, the crossbar assist mechanism 100
facilitates user manipulation of the electrical switching apparatus operating handle 32 in
order to overcome the disadvantages (e.g., without limitation, increased friction and
associated difficulty of movement of the operating handle 32 in response to elevated
temperatures of the electrical switching apparatus) of known prior art circuit breakers.
While specific embodiments of the invention have been described in
detail, it will be appreciated by those skilled in the art that various modifications and
alternatives to those details could be developed in light of the overall teachings of the
disclosure. Accordingly, the particular arrangements disclosed are meant to be
illustrative only and not limiting as to the scope of the invention which is to be given the
full breadth of the claims appended and any and all equivalents thereof.
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What is claimed is:
1. A crossbar assist mechanism (100) for an electrical switching apparatus
(2), said electrical switching apparatus (2) including a housing (4), a first conductor (6), a
second conductor (8), a movable contact (10), a stationary contact (12), and an operating
mechanism (14), said stationary contact (10) being electrically connected to said first
conductor (6), said operating mechanism (14) including a crossbar (16), a carrier (18)
having a first end (20) coupled to said crossbar (16) and a second end (22), and a
movable contact arm (24), said movable contact arm (24) being pivotably cooperable
with the second end (22) of said carrier (18), said movable contact (10) being disposed on
said movable contact arm (24), said crossbar (16) being structured to move said carrier
(18) and said movable contact arm (24), thereby moving said movable contact (10)
disposed on said movable contact arm (24) into and out of electrical contact with said
stationary contact (12), said crossbar assist mechanism (100) comprising:
an electrically conductive member (102) structured to electrically
interconnect said movable contact arm (24) of said operating mechanism (14) of said
electrical switching apparatus (2) and said second conductor (8); and
a biasing member (104) structured to be disposed between said crossbar
(16) of said operating mechanism (14) of said electrical switching apparatus (2) and said
electrically conductive member (102), and further structured to bias said crossbar (16) of
said operating mechanism (14) from a first position corresponding to said movable
contact (12) and said stationary contact (10) being separated, toward a second position
corresponding to said movable contact (12) being in electrical contact with said stationary
contact (10).
2. The crossbar assist mechanism (100) of claim 1 wherein said biasing
member comprises a spring (104); wherein said spring (104) includes a first end (106)
and a second end (108); wherein the first end (106) of said spring (104) is structured to
bias said crossbar (16) of said operating mechanism (14) of said electrical switching
apparatus (2); and wherein the second end (108) of said spring (104) is coupled to said
electrically conductive member (102).
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3. The crossbar assist mechanism (100) of claim 2 wherein said electrically
conductive member (102) includes an aperture (110) structured to receive and secure the
second end (108) of said spring (104).
4. The crossbar assist mechanism (100) of claim 3 wherein said spring (104)
is fastened to said electrically conductive member (102) in order to maintain the position
of said spring (104) within said aperture (110) of said electrically conductive member
(102).
5. The crossbar assist mechanism (100) of claim 3 wherein said electrically
conductive member (102) comprises a clinch joint (112) including a cast member (114);
wherein said cast member (114) comprises a first end (116) and a second end (118);
wherein said carrier (18) and said movable contact arm (24) of said operating mechanism
(14) of said electrical switching apparatus (2) are structured to be pivotably and
electrically coupled at or about the first end (116) of said cast member (114); and wherein
the second end (118) of said cast member (114) is electrically coupled to said load
conductor (8).
6. The crossbar assist mechanism (100) of claim 5 wherein said cast member
(114) further comprises a top (120); wherein said aperture of said cast member (114)
comprises an elongated slot (110) in the top (120) of said cast member (114); wherein the
second end (108) of said spring (104) includes at least one coil (124); and wherein said at
least one coil (124) of the second end (108) of said spring (104) is disposed within said
elongated slot (110) of said cast member (114).
7. The crossbar assist mechanism (100) of claim 2 wherein said spring
comprises a conical spring (104); wherein the first end (106) of said conical spring (104)
has a first diameter (107); wherein the second end (108) of said conical spring (104) has a
second diameter (109); and wherein the first diameter (107) of the first end (106) of said
conical spring (104) is smaller than the second diameter (109) of the second end (108) of
said conical spring (104).
8. The crossbar assist mechanism (100) of claim 7 wherein said conical
spring (104) is structured to be compressed substantially flat when said crossbar (16) of
said operating mechanism (14) of said electrical switching apparatus (2) is disposed in
said first position; and wherein in response to partial movement of said operating
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mechanism (14) from said first position toward said second position, said conical spring
(104) is structured to provide a spring force to said crossbar (16) in order to facilitate the
movement of said operating mechanism (14) toward said second position.
9. The crossbar assist mechanism (100) of claim 7 wherein the first end (106)
of said conical spring (104) includes at least one coil (122); and wherein said at least one
coil (122) of the first end (106) of said conical spring (104) includes a substantially flat
exterior surface (126) structured to provide flush engagement with said crossbar (16) of
said operating mechanism (14) of said electrical switching apparatus (2).
10. The crossbar assist mechanism (100) of claim 1 wherein said first
conductor comprises a line conductor (6); and wherein said second conductor comprises a
load conductor (8).
11. An electrical switching apparatus (2) comprising:
a housing (4);
separable contacts (10,12) housed by said housing (4), said separable
contacts comprising at least one movable contact (10) and at least one stationary contact
(12);
an operating mechanism (14) comprising a crossbar (16), at least one
carrier (18), and at least one movable contact arm (24), each of said at least one movable
contact (10) being disposed on a corresponding one of said at least one movable contact
arm (24), said at least one carrier (18) having a first end (20) coupled to said crossbar
(16) and a second end (22) pivotably cooperating with said corresponding one of said at
least one movable contact arm (24), said operating mechanism (14) moving said at least
one carrier (18) and said corresponding one of said at least one movable contact arm (24),
thereby moving said at least one movable contact (10) disposed on said corresponding
one of said at least one movable contact arm (24) into and out of electrical contact with a
corresponding one of said at least one stationary contact (12); and
at least one crossbar assist mechanism (100), each of said at least one
crossbar assist mechanism (100) comprising:
an electrically conductive member (102), said electrically
conductive member (102) being electrically connected to said at least one carrier (18) and
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said corresponding one of said at least one movable contact arm (24) of said operating
mechanism (14), and
a biasing member (104) disposed between said crossbar (16) of
said operating mechanism (14) and said electrically conductive member (102), in order to
bias said crossbar (16) of said operating mechanism (14) from a first position
corresponding to said at least one movable contact (10) and said corresponding one of
said at least one stationary contact (12) being separated, toward a second position
corresponding to said at least one movable contact (10) being in electrical contact with
said corresponding one of said at least one stationary contact (12).
12. The electrical switching apparatus (2) of claim 11 wherein said biasing
member comprises a spring (104); wherein said spring (104) includes a first end (106)
and a second end (108); wherein the first end (106) of said spring (104) biases said
crossbar (16) of said operating mechanism (14); and wherein the second end (108) of said
spring (104) is coupled to said electrically conductive member (102).
13. The electrical switching apparatus (2) of claim 12 wherein said electrically
conductive member (102) includes an aperture (110); and wherein said aperture (110)
receives and secures the second end (108) of said spring (104).
14. The electrical switching apparatus (2) of claim 13 wherein said spring
(104) is fastened to said electrically conductive member (102) in order to maintain the
position of said spring (104) within said aperture (110) of said electrically conductive
member (102).
15. The electrical switching apparatus (2) of claim 13 wherein said electrically
conductive member (102) comprises a cast member (114); wherein said cast member
(114) comprises a first end (116) and a second end (118); and wherein said at least one
carrier (18) of said operating mechanism (14) and said corresponding one of said at least
one movable contact arm (24) of said electrical switching apparatus (2) are pivotably and
electrically coupled at or about the first end (116) of said cast member (114).
16. The electrical switching apparatus (2) of claim 15 wherein said cast
member (114) further comprises a top (120); wherein said aperture (110) of said cast
member (114) comprises an elongated slot (110) in the top (120) of said cast member
(114); wherein the second end (108) of said spring (104) includes at least one coil (124);
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and wherein said at least one coil (124) of the second end (108) of said spring (104) is
disposed within said elongated slot (10) of said cast member (114).
17. The electrical switching apparatus (2) of claim 12 wherein said electrically
conductive member (102) comprises a cast member (114); wherein said cast member
(114) comprises a first end (116) and a second end (118); wherein said at least one carrier
(18) of said operating mechanism (14) and said corresponding one of said at least one
movable contact arm (24) of said electrical switching apparatus (2) are pivotably and
electrically coupled at or about the first end (116) of said cast member (114); and wherein
the second end (108) of said spring (104) is coupled to said cast member (114).
18. The electrical switching apparatus (2) of claim 12 wherein said spring
comprises a conical spring (104); wherein the first end (106) of said conical spring (104)
has a first diameter (107); wherein the second end (108) of said conical spring (104) has a
second diameter (109); and wherein the first diameter (107) of the first end (106) of said
conical spring (104) is smaller than the second diameter (109) of the second end (108) of
said conical spring (104).
19. The electrical switching apparatus (2) of claim 18 wherein said conical
spring (104) is compressed substantially flat when said crossbar (16) of said operating
mechanism (14) of said electrical switching apparatus (2) is disposed in said first
position; and wherein in response to partial movement of said operating mechanism (14)
from said first position toward said second position, said conical spring (104) provides a
spring force to said crossbar (16) in order to facilitate the movement of said operating
mechanism (14) toward said second position.
20. The electrical switching apparatus (2) of claim 18 wherein the first end
(106) of said conical spring (104) includes at least one coil (122); wherein said at least
one coil (122) of the first end (106) of said conical spring (104) includes a substantial flat
exterior surface (126); and wherein said substantially flat exterior surface (126) flushly
engages said crossbar (16) of said operating mechanism (14).
21. The electrical switching apparatus (2) of claim 11 wherein said electrical
switching apparatus is a circuit breaker (2) having a plurality of poles (26,28,30);
wherein each of said poles (26,28,30) of said circuit breaker (2) comprises a single carrier
(18) including a first end (20) and a second end (22), said single carrier (18) being
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05-EDP-320
coupled at or about the first end (20) thereof to said crossbar (16) of said operating
mechanism (14), a single movable contact arm (24) pivotably cooperable with the second
end (22) of said single carrier (18), a single movable contact (10) disposed on said single
movable contact arm (24), and a single corresponding stationary contact (12); and
wherein said at least one crossbar assist mechanism (100) comprises a separate crossbar
assist mechanism (100) for each of the poles (26,28,30) of said circuit breaker (2).
22. The electrical switching apparatus (2) of claim 21 wherein said operating
mechanism (14) further comprises an operating handle (32); wherein said operating
handle (32) includes a first end (34) accessible from the exterior of said housing (4) of
said circuit breaker (2), and a second end (36) coupled to said crossbar (18) of said
operating mechanism (14); wherein said operating handle (32) is operable among an OFF
position and an ON position; wherein said OFF position corresponds to said first position
of said operating mechanism (14); wherein said ON position corresponds to said second
position of said operating mechanism (14); and wherein said at least one crossbar assist
mechanism (100) facilitates movement of said operating handle (32) from said OFF
position toward said ON position.
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A crossbar assist mechanism (100) is for a circuit breaker (2) including a
housing (4), a movable contact (10), a stationary contact (12), and an operating
mechanism (14). The operating mechanism (14) includes a crossbar (16), a carrier (18) coupled to the crossbar (16), and a movable contact arm (24) which is pivotably
cooperable with the carrier (18). The movable contact (10) is disposed on the movable
contact arm (24). The crossbar (16) moves the carrier (18) and the movable contact arm (24), thereby moving the movable contact (10) into and out of electrical contact with the stationary contact (12). The crossbar assist mechanism (100) includes an electrically conductive member (102) electrically interconnecting the carrier (18) and the movable contact arm (24) to a load terminal (8). A spring (104) disposed between the crossbar (16) and the electrically conductive member (102) biases the crossbar (16) from a first position corresponding to the movable contact (10) and the stationary contact (12) being separated, toward a second position corresponding to the movable contact (10) being in electrical contact with the stationary contact (12).