CLOSING PROTECTION MECHANISM FOR
A CLOSING ASSEMBLY OVER-TOGGLE LINKAGE
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to an electrical switching apparatus operating
mechanism and, more specifically to a closing protection mechanism for a closing
assembly having an over-toggle linkage.
Background Information
An electrical switching apparatus, typically, includes a housing, at least one
bus assembly having a pair of contacts, a trip device, and an operating mechanism.
The housing assembly is structured to insulate and enclose the other components. The
at least one pair of contacts include a fixed contact and a movable contact and
typically include multiple pairs of fixed and movable contacts. Each contact is
coupled to, and in electrical communication with, a conductive bus that is further
coupled to, and in electrical communication with, a line or a load. A trip device is
structured to detect an over current condition and to actuate the operating mechanism.
An operating mechanism is structured to both open the contacts, either manually or
following actuation by the trip device, and close the contacts.
That is, the operating mechanism includes both a closing assembly and an
opening assembly, which may have common elements, that are structured to move the
movable contact between a first, open position, wherein the contacts are separated,
and a second, closed position, wherein the contacts are coupled and in electrical
communication. The operating mechanism includes a rotatable pole shaft that is
coupled to the movable contact and structured to move each movable contact between
the closed position and the open position. Elements of both the closing assembly and
the opening assembly are coupled to the pole shaft so as to effect the closing and
opening of the contacts. The closing assembly may be actuated manually by a user
input or in response to an input from a remote actuator.
The trip device included an over-current sensor, a latch assembly and may
have included one or more additional links that were coupled to the toggle assembly.

Alternately, the latch assembly was directly coupled to the toggle assembly. When an
over-current situation occurred, the latch assembly was released allowing the opening
spring to cause the toggle assembly to collapse. When the toggle assembly collapsed,
the toggle assembly link coupled to the pole shaft caused the pole shaft to rotate and
thereby move the movable contacts into the open position.
Low and medium voltage electrical switching apparatus typically had stored
energy devices, such as a closing spring and an opening spring, and at least one link
coupled to the pole shaft. The at least one link, typically, included two links that
acted cooperatively as a toggle assembly and which were coupled to each other at a
toggle joint. When the contacts were open, the toggle assembly was in a first,
collapsed configuration and, conversely, when the contacts were closed, the toggle
assembly was, typically, in a second, toggle position, that is, an in-line configuration,
or in a slightly over-toggle position. The closing spring was usually compressed, or
"charged," by a motor or a user utilizing a lever arm. The closing spring, typically,
holds more stored energy than the opening springs and during the closing operation
wherein the contacts are moved to the second, closed position, the opening spring was
charged. The opening spring biased the pole shaft, and therefore the toggle assembly,
to the collapsed position. The opening spring and toggle assembly were maintained in
the second, toggle position by the trip device.
When the contacts were in the first, open position, the toggle assembly links,
which define lines of force, were "folded," typically at an acute angle. When the
mechanism was closing, a closing component applied a closing force to the toggle
joint. The closing component moved the links until the lines of force, that is, the
links, were nearly in-line or on "center." If the fully closed position of the separable
contacts was reached before the lines of force were fully in-line, the closing assembly
is an "under-toggle" mechanism and the toggle joint continued to rest on the closing
component to prevent the toggle joint from collapsing. In this type of closing
assembly, the closing component was, typically, a cam. If, during closing, the closing
component moved the toggle joint through the in-line position and beyond, the
closing assembly is an "over-toggle" mechanism and the toggle joint typically rested
upon a stop that is separate from the closing component. That is, the toggle joint

typically came to rest on a stop pin that prevented the toggle joint from collapsing in a
reverse direction.
In either an under-toggle or over-toggle mechanism, the contacts would
initially engage each other when the angle of the lines of force were approaching the
in-line position. After the contacts engage, the driving force required to complete the
closing of the contacts increases. That is, prior to the contacts engaging each other,
the closing component was, essentially, only moving the moving contact and
compressing the opening springs. Once the contacts engaged each other, the closing
component was required to overcome any electromagnetic forces generated by a
current passing through the contacts, as well as, forces created by the contact spring as
they were being compressed. If the closing component was not able to overcome
these forces, there was a chance that the closing operation could stall. If the closing
operation stalls, dangerous arcing may occur at the contacts if the contacts are subject
to inadequate force or support, for example is the contacts are held in close proximity
or if the contacts slowly separate from each other.
Some under-toggle mechanisms have attributes that mitigate the consequences
of a stall. That is, when the closing component is a cam acting upon the toggle joint,
the cam surface is rising, that is, increasing in radius, so as to effect the movement of
the toggle joint. Such a cam is structured to rotate in a single direction during closing,
wherein the radius of the cam is increasing, and subsequent charging, wherein the
radius of the cam is generally constant. Thus, if a stall occurs, the cam needs only to
be rotated further, such as by charging after the close attempt, to cause the toggle joint
to be moved into the proper position.
An over-toggle mechanism, however, is not structured to be supported by the
closing component. Typically, the closing component acts upon the toggle joint and
is then, slowly, withdrawn during the charging of the closing spring. Thus, unlike an
under-toggle mechanism, a stall in such a closing assembly could allow the toggle
joint to return to the open configuration. If, for example, the toggle joint is resting on
the closing component as it is being slowly withdrawn, the contacts will be slowly
separated allowing for dangerous arcing to occur.
It is further noted that a device may have a high-current capacity for
withstanding an electrical fault that appears after the device is already closed, but may

not have enough mechanical energy to complete a closure on that same fault current.
That is, high current flowing in the device adds electromagnetic force to the springs
which resist closing and increasing the mechanical energy to close on all such faults
would shorten the mechanical life or add cost to the mechanism. The trip device is
often self-powered by current passing through the contacts of the electrical switching
apparatus, and therefore the trip device is inactive before closing. If a fault current
which is higher than the closing, or "making" capacity, but lower than the "withstand"
capacity appears in the electrical switching apparatus, the trip device must determine
if the operating mechanism is closing, in which case the trip device should trip open
to protect against harmful arcing at the contacts due to stalling at less-than-fully-
closed, or the operating mechanism was already closed, in which case the trip device
should remain closed until the manufacturer or customer-programmed delay time for
tripping is reached.
One strategy for immediately tripping an operating mechanism that is closing
on a fault above its making capacity is the use of a "time-delay" switch. This type of
switch senses the state of the device, typically by sensing the pole shaft position, and
connects to the trip device. The switch is held in one state when the device is open,
and released to move to its other state when the electrical switching apparatus is
closed. The switch assembly typically contains a mass with a relatively light bias
spring resulting in an inertial delay off its motion when the device closes. This delay
serves as a mechanical memory used by the trip device when a fault current above the
making capacity appears. If the switch indicates the "device-closed" position, then
the device was already closed some moments before the current appeared and the
operating mechanism is not attempting to close on the high current; therefore it is not
necessary to trip open to protect against prolonged harmful arcing. If the switch still
indicates the "device-open" position, then the device was open moments before and
the current flowing is the result of a closure attempt. Thus, the trip device must
immediately re-open the contacts to protect against a potential stall.
As a result of its kinematics, an over-toggle mechanism has the characteristic
of "over-driving" the contacts as the lines of force passes through in-line, or "center",
before settling back to the full closed position. Therefore, in a normal closing, the
pole shaft is at the full closed position twice; once before the lines of force reach

center, and again after passing through center. A switch sensing the pole shaft
position, such as the time delay switch, is not able to discriminate between fully
closed and partially-closed, where it could potentially stall. Despite these
characteristics, there are some reasons to select over-toggle mechanism for some
applications, rather than under-toggle mechanisms.
SUMMARY OF THE INVENTION
The closing protection mechanism provided herein includes a control unit, a
sensing switch and a sensing switch actuator. The control unit is coupled to, and in
electronic communication with, the trip device. The control unit is structured to
receive a sensing switch signal and to provide a control signal to the trip device. The
sensing switch is coupled to, and in electronic communication with, the control unit.
The sensing switch is disposed adjacent to the toggle assembly. The sensing switch is
structured to provide a sensing switch signal to the control unit. The sensing switch
actuator is disposed on the toggle assembly. The sensing switch actuator is structured
to actuate the sensing switch. The sensing switch is structured to be actuated by the
sensing switch actuator when the toggle assembly is in the second, over-toggle
configuration.
Thus, the sensing switch detects the "toggle angle" between the lines of force
of the toggle assembly and allows for schemes for applying such information to
protect against potential stalled closures. The sensing switch of this invention also
allows unimpeded tripping motion out of any condition between and including open
and closed in this embodiment, the switch is mounted to the mechanism side plate and
actuated by a cam lobe at the fixed end of the support link. Preferably, the toggle
assembly is driven by a ram assembly as set forth in Application Serial No.
11/693,198, filed March 29, 2007, entitled "SPRING DRIVEN RAM FOR CLOSING
AN ELECTRICAL SWITCHING APPARATUS" (Attorney Docket No. 07-EDP-
044) which is incorporated by reference.
Any time enough current to sense and self-power the trip unit is flowing
through the device, a timer, preferably in the control unit, starts counting a number of
milliseconds. If the sensing switch does not indicate full closed within the preset
time, which may be based on the maximum expected duration of a complete closure

at the current range sensed, and could be shorter - including zero delay - if desired to
maximize protection at high currents, the electrical switching apparatus trips.
Tripping for this reason may create a "cause of trip code" that can be identified by on
a display. If a current, even a current close to the "withstand" limit, is sensed, but the
sensing switch indicates full-closed, or begins to indicate full-closed within the
allowed number of milliseconds, the trip device would sense full successful closure
and revert to an appropriate pre-programmed trip delay settings for the current level
sensed. Maximum continuity of service is achieved by further sensing the actual
outcome in addition to the "predicted" outcome of an attempt to close an individual
electrical switching apparatus in its service conditions.
Alternatively, the trip device could be configured not to trip due to a perceived
stall condition unless the current is larger than a pre-selected threshold. When the
sensing switch reports that the operating mechanism is not fully closed at currents
below the threshold, which are less probable events and do not present substantial
immediate danger, the contacts would remain closed and a diagnostic code, such as,
but not limited to, a unique flashing pattern of a "status" LED could be used to signal
a user that the device may not be fully closed, or that there may be a problem with the
switch. If an overload or fault current appears later, the trip device would trip the
operating mechanism at an appropriate time. This option would further ensure best
continuity of service and remove concerns about the reliability of the switch itself or
the wiring by eliminating normal-load-current nuisance trips.
It is noted that this configuration has the added benefit of protection when a
stalled close occurred with an un-energized primary circuit and then the trip device is
later energized when current begins flowing. A time-delay switch would have lost its
memory, which extends only a number of milliseconds prior to the appearance of
current. A stall is least likely to occur when there is no "electrical load" but is still
possible considering the variation and potential "noise factors" a device may be
exposed to during its life.
The tolerance band for the point at which the sensing switch changes state to
report full closed is the range between in-line configuration and fully closed over-
toggle configuration, allowing for practical placement of the sensing switch even with
normal product variation. Once the lines of force in the toggle assembly have moved

past center, the toggle assembly can be expected to continue to "fully closed" under
the forces acting on the toggle assembly. Any position past center constitutes a band
where the electrical switching apparatus can safely be considered definitively closed.
An over-toggle mechanism has the advantage of this definite band for sensing fully
closed, whereas the closed position is less discretely defined on an under-toggle
mechanism.
The described closing protection mechanism may also be used as a "trip unit
auxiliary switch" that is used on advanced trip units for communicating electrical
switching apparatus status, counting close-open operations, and collecting or
communicating similar data. Other advantages include its low cost, compactness and
mechanical simplicity. It does not require a "mechanical memory" device with its
critical balance of force, mass and friction. It is also less susceptible to mechanical
shock and insensitive to the electrical switching apparatus orientation.
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 an isometric view of an electrical switching apparatus with a front
cover removed.
Figure 2A is a side view of an electrical switching apparatus with a front cover
removed and selected components removed for clarity and with the latch assembly in
a first position. Figure 2B is a side view of an electrical switching apparatus with a
front cover removed and selected components removed for clarity and with the latch
assembly in a second position.
Figure 3 is an isometric view of the closing assembly with a side plate
removed for clarity.
Figure 4 is a side view of the ram assembly and the toggle assembly in a first
position/configuration.
Figure 5 is a side view of the ram assembly and the toggle assembly in a
second position/configuration.

Figure 6 is a schematic side view of the closing protection mechanism with the
toggle assembly in the first, open configuration.
Figure 7 is a schematic side view of the closing protection mechanism with the
toggle assembly just prior to passing through the in-line configuration.
Figure 8 is a schematic side view of the closing protection mechanism with the
toggle assembly in the in-line configuration.
Figure 9 is a schematic side view of the closing protection mechanism with the
toggle assembly in the second, closed configuration.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As used herein, "coupled" means a link between two or more elements,
whether direct or indirect, so long as a link occurs.
As used herein, "directly coupled" means that two elements are directly in
contact with each other.
As used herein, "fixedly coupled" or "fixed" means that two components are
so coupled move as one.
As used herein, "operatively engage" when used in relation to a component
that is directly coupled to a cam means that a force is being applied by that component
to the cam sufficient to cause the cam to rotate.
As shown in Figure 1, an electrical switching apparatus 10 includes a housing
assembly 12 defining an enclosed space 14. In Figure 1, the front cover of the
housing assembly 12 is not shown, but it is well known in the art. The electrical
switching apparatus 10 further includes a conductor assembly 20 (shown
schematically) having at least one line terminal 22, at least one line conductor 24, at
least one pair of separable contacts 26, at least one load conductor 28 and at least one
load terminal 30. The at least one pair of separable contacts 26 include a fixed
contact 32 and a movable contact 34. The movable contact 34 is structured to move
between a first, open position, wherein the contacts 32, 34 are separated, and a
second, closed position, wherein the contacts 32, 34 contact each other and are in
electrical communication. The electrical switching apparatus 10 further includes a
trip device 40 and an operating mechanism 50. The operating mechanism 50, which
is discussed in more detail below, is generally structured to move the at least one pair

of separable contacts 26 between the first, open position and the second, closed
position. The trip device 40 is structured to detect an over current condition and,
upon detecting such a condition, to actuate the operating mechanism 50 to open the at
least one pair of separable contacts 26.
The electrical switching apparatus 10 also includes at least two, and typically a
plurality, of side plates 27. The side plates 27 are disposed within the housing
assembly 12 in a generally parallel orientation. The side plates 27 include a plurality
of openings 29 to which other components may be attached or through which other
components may extend. As discussed below, the openings 29 on two adjacent side
plates 27 are typically aligned. While side plates 27 are the preferred embodiment, it
is understood that the housing assembly 12 may also be adapted to include the
required openings and/or attachment points thereby, effectively, incorporating the side
plates 27 into the housing assembly 12 (not shown).
An electrical switching apparatus 10 may have one or more poles, that is, one
or more pairs of separable contacts 26 each having associated conductors and
terminals. As shown in the Figures, the housing assembly 12 includes three chambers
13A, 13B, 13C each enclosing a pair of separable contacts 26 with each being a pole
for the electrical switching apparatus 10. A three-pole configuration, or a four-pole
configuration having a neutral pole, is well known in the art. The operating
mechanism 50 is structured to control all the pairs of separable contacts 26 within the
electrical switching apparatus 10. Thus, it is understood selected elements of the
operating mechanism 50, such as, but not limited to, the pole shaft 56 (discussed
below) span all three chambers 13A, 13B, 13C and engage each pair of separable
contacts 26. The following discussion, however, shall not specifically address each
specific pair of separable contacts 26.
As shown in Figure 2, the operating mechanism 50 includes an opening
assembly 52, structured to move the at least one pair of separable contacts 26 from the
second, closed position to the first, open position, and a closing assembly 54,
structured to move the at least one pair of separable contacts 26 from the first, open
position to the second closed position. The opening assembly 52 and the closing
assembly 54 both utilize common components of the operating mechanism 50. The
opening assembly 52 is not part of the claimed invention, however, for the purpose of

the following discussion, it is understood that the opening assembly 52 is the
assembly structured to move various components to the positions discussed below.
Further, it is noted that the opening assembly 52 includes a cradle assembly 53 that,
among other functions, acts as a toggle stop and as a toggle kicker for the toggle
assembly 58 (discussed below).
As shown in Figures 2-4, the closing assembly 54 includes a pole shaft 56, a
toggle assembly 58, a ram assembly 60, and a charging assembly 62 (Fig. 1). The
pole shaft 56 is an elongated shaft body 64 rotatably coupled to the housing assembly
12 and/or side plates 27. The pole shaft 56 includes a plurality of mounting points 66
disposed on mounting blocks 68 extending from the pole shaft body 64. , The pole
shaft 56 is coupled to the movable contact 34. The pole shaft 56 is structured to move
between a first position, wherein the movable contact 34 is in its first, open position,
and a second position, wherein the movable contact 34 is in its second, closed
position.
It is noted that, as shown in Figure 3, a single "link" in the toggle assembly 58
may include two, or more, members 59A, 59B with similar shapes which are held in a
spaced relationship and which move in concert. The use of multiple link members
59A, 59B may be used, for example, to provide added strength to the link or where
space considerations do not allow for a single thick link. Because these link members
59A, 59B perform the same function, have a similar shape, and move in concert, the
following discussion will simply identify the link by a single reference number as is
shown in the side views of Figures 4 and 5. It is understood that the description of a
link applies to both link members 59A, 59B. Other components in the closing
assembly 54 may also be constructed using various laminations or layers which
sandwich each other. It is further understood that these components, such as, but not
limited to, the toggle assembly members 59A, 59B and the rocker arm assembly body
160 (discussed below) each move in their own plane. The plane of travel for such
components is generally parallel to the plane of the side plates 27.
As shown in Figures 4 and 5, the toggle assembly 58 includes a first link 70
and a second link 72 which are each generally flat, elongated bodies. The first and
second links 70, 72 each have a first, outer end 74, 76 (respectively) and a second,
inner end 78, 80 (respectively). The first link 70 and the second link 72 are rotatably

coupled together at the first link inner end 78 and the second link inner end 80. In this
configuration, the first and second links 70, 72 form a toggle joint 82. The toggle
joint 82 may include a toggle roller 86. That is, the first link inner end 78 and the
second link inner end 80 may be rotatably coupled together by a pin 84 extending
generally perpendicular to the plane of each link 70, 72. The pin 84 may also define
an axle for the toggle roller 86 which is, essentially, a wheel. The toggle roller 86 has
a diameter of sufficient size to extend past the edges of the first and second links 70,
72. The first link outer end 74 is rotatably coupled to the housing assembly 12 and/or
side plates 27. For the purpose of this disclosure, the first link outer end 74 may be
considered to be fixed pivot point, however, it is noted that the first link outer end 74
is movably mounted in a slot 25 on the side plate 27. The second link outer end 76 is
rotatably coupled to the pole shaft 56 and, more specifically, rotatably coupled to a
mounting point 66. see-136
It is noted that an axis extending through the pivot points for each link 70, 72
defines the lines of force acting through the toggle assembly 58. The toggle assembly
58 is structured to move between a first, collapsed configuration (Fig. 4) and a
second, slightly over-toggle configuration (Fig. 5). While moving between the first,
collapsed configuration and the second, over-toggle configuration the toggle assembly
58 and the toggle joint 82 pass through a toggle, or in-line, configuration. In the first,
collapsed configuration, the lines of force acting through the toggle assembly 58 are,
preferably, at an acute angle. In the in-line configuration, the lines of force acting
through the toggle assembly 58 are aligned with each other. In the over-toggle
configuration, the lines of force acting through the toggle assembly 58 are typically
between about 5 degrees and 15 degrees past toggle and, preferably about 10 degrees
past toggle. The toggle assembly 58 may be held in the over-toggle configuration by
a stop pin 79. That is, the stop pin 79 prevents the toggle assembly 58 from
collapsing in the reverse direction.
In the first, collapsed configuration, the first and second link outer ends 74, 76
are generally closer together than when the toggle assembly 58 is in the second, over-
toggle configuration. Thus, because the first link outer end 74 is a fixed pivot point,
as the toggle assembly 58 moves between the first, collapsed configuration and the
second, over-toggle configuration, the second link outer end 76 is drawn toward, or

pushed away from, the first link outer end 74. This motion causes the pole shaft 56 to
move between its first and second positions. That is, when the toggle assembly 58 is
in the first, collapsed configuration, the pole shaft 56 is in its first position, and, as
noted above, the movable contact 34 is in its first, open position. Further, when the
toggle assembly 58 is in the second, over-toggle configuration, the pole shaft 56 is in
its second position, and, as noted above, the movable contact 34 is in its second,
closed position.
The ram assembly 60 has at least one biasing device 89, preferably a
compression spring 90, a guide assembly 92, and a ram body 94. The ram body 94,
preferably, includes a generally flat forward surface 96 that is structured to engage the
toggle joint 82, and more preferably the toggle roller 86. The ram body 94 may be
solid but, in a preferred embodiment, the ram body 94 is substantially hollow having a
loop-like side wall 95 (Fig. 3 ) coupled to cap-like a front plate 93 (Fig. 2A). The
forward surface 96 is the outer surface of the front plate 93. The ram body 94 is
structured to move between a first, retracted position and a second, extended position
along a path of travel defined by the guide assembly 92. In one embodiment, the ram
body 94 has a lateral width of about 2.1 inches and defines at least one, and preferably
two passages 98, 99 (Fig. 3) extending in the direction of the path of travel. The ram
body 94 may also have at least one, and preferably two rollers 100 disposed on
opposite lateral sides of the ram body 94. The passages 98, 99 and the ram rollers 100
cooperate with an associated embodiment of the guide assembly 92. That is, for this
embodiment, the guide assembly 92 includes at least one, and preferably two
elongated, generally straight pins 104, 106 (Fig. 3) that are disposed in a spaced,
generally parallel orientation. Further, the housing assembly 12 and/or side plates 27
may define slots 25 disposed on either side of the ram body 94 path of travel. When
assembled, the pins 104, 106 extend through the passages 98, 99 and the ram body
rollers 100 are each disposed in one of the slots 25. In this configuration, the ram
body 94 is limited to a generally linear motion defined by the guide assembly 92.
The guide assembly 92 further includes a base plate 110 and a stop plate 112.
Each pin 104, 106 has a base end 114 and a tip end 116. Each pin base end 114 is
coupled to the base plate 110 and each pin tip end 116 is coupled to the stop plate 112
(Fig. 5). That is, the base plate 110 and the stop plate 112 maintain the pins 104, 106

in a spaced, generally parallel configuration. Further, in the embodiment described
above, the base plate 110 and the stop plate 112 further limit and define the ram body
94 path of travel. That is, the ram body 94 is trapped between the base plate 110 and
the stop plate 112.
The at least one spring 90 is structured to bias the ram body 94 from the first,
retracted position toward the second, extended position. When the ram body 94 is in
the first, retracted position, the at least one spring 90 is charged or compressed. When
the ram body 94 is in the second, extended position, the at least one spring 90 is
discharged. Preferably, the at least one spring 90 is disposed between the base plate
110 and a ram body back surface 97 (Fig. 2B). The ram body back surface 97 is,
preferably, the interior side of the front plate 93. That is, the ram body back surface
97 is disposed on the opposite side of the front plate 93 from the forward surface 96.
In the embodiment disclosed above, i.e., a ram body 94 with two passages 98, 99 and
two pins 104, 106, the at least one spring 90 is preferably two springs 120, 122 and
each spring 120, 122 is disposed about one of the two pins 104, 106. For a 600 volt
electrical switching apparatus, wherein the closing energy required to close three pairs
of contacts 26 is as much as 50 joules, the springs 120, 122 may each be about 3.5
inches long and about 0.75 inches in diameter.
As shown in Figures 1 and 2, the charging assembly 62 includes a charging
operator 130, a cam shaft 132, a cam 134, and a rocker arm assembly 136. The
charging operator 130 is a device coupled to, and structured to rotate, the cam shaft
132. The charging operator 130 may be a manually powered handle assembly 140
and/or a powered motor 142 as shown in Figure 1. The cam shaft 132 is an elongated
shaft that is rotatably coupled to the housing assembly 12 and/or side plates 27. The
cam 134 is fixed to the cam shaft 132 and structured to rotate therewith about a pivot
point. The cam 134 includes an outer cam surface 150. The outer cam surface 150
has a point of minimal radius 152, a point of greatest radius 154, and a stop radius
155. The cam 134 is structured to rotate in a single direction as indicated by the
arrow in Figure 2. The outer cam surface 150 increases gradually in radius from the
point of minimal radius 152 to the point of greatest radius 154 in the direction of
rotation. After the cam point of greatest radius 154, the radius of the outer cam
surface 150 is reduced slightly over a downslope 153. The downslope 153 leads to a

stop radius 155 and then a tip 157. As set forth below, the downslope 153 to the stop
radius 155 is a surface to which the force from the at least one spring 90 is applied
and which encourages rotation in the proper direction so that when the "close latch"
releases the cam shaft 132 rotates from the stop radius 155 to the cam tip 157 where
the cam follower 164 falls off the cam tip 157 and into the pocket of the cam 152. As
is shown, the outer cam surface point of minimal radius 152 and the outer cam tip 157
are disposed immediately adjacent to each other on the outer cam surface 150. Thus,
there is a step 156 between the point of minimal radius 152 and the cam tip 157. It is
further noted that, due to the radius of the cam follower 164 (discussed below) the
cam follower 164 does not engage the point of minimal radius 152, but rather engages
a stop adjacent to the point of minimal radius 152. -136 separate stop
The rocker arm assembly 136 includes an elongated body 160 having a pivot
point 162, a cam follower 164, and a ram body contact point 166. The rocker arm
assembly body 160 is pivotally coupled to housing assembly 12 and/or side plates 27
at the rocker arm body pivot point 162. The rocker arm assembly body 160 may
rotate about the rocker arm body pivot point 162 and is structured to move between a
first position, wherein the rocker arm body ram body contact point 166 is disposed
adjacent to the base plate 110, and a second position, wherein the rocker arm body
ram body contact point 166 is adjacent to the stop plate 112. As used immediately
above, "adjacent" is a comparative adjective relating to the positions of the rocker arm
assembly body 160. The rocker arm body ram body contact point 166 is structured to
engage and move the ram body 94. As shown, the rocker arm body ram body contact
point 166 engages a bearing 101 (Fig. 3) disposed about the axle of one of the ram
body rollers 100. The rocker arm assembly body 160 moves within a plane that is
generally parallel to the ram body 94 path of travel and, more preferably, in a plane
generally parallel to the plane of the side plates 27. The rocker arm body cam
follower 164 extends generally perpendicular to the longitudinal axis of the rocker
arm assembly body 160 and is structured to engage the outer cam surface 150. The
rocker arm body cam follower 164 may include a roller 170.
The closing assembly 54 is assembled in the housing assembly 12 as follows.
The toggle assembly 58 is disposed with the first link outer end 74 being rotatably
coupled to the housing assembly 12 and/or side plates 27. The second link outer end

76 is rotatably coupled to the pole shaft 56 and, more specifically, rotatably coupled
to a mounting point 66. The ram assembly 60 is disposed adjacent to the toggle
assembly 58 with the ram body forward surface 96 adjacent to the toggle joint 82.
That is, the toggle assembly 58 and the ram assembly 60 are positioned relative to
each other so that the toggle joint 82 is disposed within the ram body 94 path of
travel. More specifically, the toggle joint 82 also moves through a path as the toggle
assembly 58 moves between the first, collapsed configuration and the second, over-
toggle configuration. The path of the toggle joint 82 is disposed, generally, within the
ram body 94 path of travel. Thus, the ram body 94 is structured to engage the toggle
joint 82. In a preferred embodiment, the ram body 94 path of travel does not extend
to the position of the toggle joint 82 when the toggle assembly 58 is in the second,
over-toggle configuration.
The rocker arm assembly 136 assembly is disposed within the housing
assembly 12 adjacent to the ram assembly 60. More specifically, the rocker arm body
ram body contact point 166 is disposed so as to contact the forward side, that is the
side opposite the at least one spring 90, of a ram body roller 100. In this
configuration, rotation of the cam 134 causes the ram body 94 to move between the
second, extended position and the first, retracted position. That is, assuming the ram
body 94 is in the second, extended position and the cam follower 164 is disposed on
the outer cam surface 150 at a point adjacent to the outer cam surface point of
minimal radius 152, then the rocker arm assembly body 160 is in the second position.
Upon actuation of the charging operator 130, the cam shaft 132 and the cam 134
rotate causing the cam follower 164 to move over the outer cam surface 150. At the
point where the cam follower 164 engages the outer cam surface 150, the relative
radius of the outer cam surface 150 increases with the continued rotation. As the
relative radius of the outer cam surface 150 is increasing the rocker arm assembly
body 160 is moved to the first position. As the rocker arm assembly body 160 is
moved to the first position, the rocker arm body ram body contact point 166 engages
the ram body bearing 101 and moves the ram body 94 to the first position, thereby
compressing the at least one spring 90. When the ram body 94 is moved to the first
position, the rocker arm body cam follower 164 is disposed at the stop radius 155.
When the rocker arm body cam follower 164 is disposed on the stop radius 155, the

force from the at least one spring 90 is transferred via the ram body 94 and the rocker
arm assembly body 160 to the cam 134. That is, the force is being applied in a
generally radially inward direction. Because the cam radius at the stop radius 155 is
less than at the cam point of greatest radius 154, the cam 134 is encouraged to rotate
away from the cam point of greatest radius 154, i.e. toward the step 156. The rotation
of the cam shaft 132 is controlled by the latch assembly 180, discussed below.
In this position, any further rotation of the cam 134 will allow the rocker arm
body cam follower 164 to fall over the step 156. After the rocker arm body cam
follower 164 falls over the step 156, the rocker arm body cam follower 164 does not
operatively engage the cam 134. That is, while there may be some minor force
applied to the cam 134 by the rocker arm body cam follower 164, this force is not
significant, does not cause the cam 134 to rotate, and does not cause significant wear
and tear on the cam 134. It is noted that the cam 134 may rotate due to momentum
imparted by the rocker arm body cam follower 164 prior to the rocker arm body cam
follower 164 to falling over the step 156. Further, as the rocker arm body cam
follower 164 falls over the step 156, the rocker arm assembly body 160 is free to
move to the second position as the rocker arm body cam follower 164 is now disposed
adjacent to the outer cam surface point of minimal radius 152. It is observed that,
when the rocker arm body cam follower 164 is disposed at the outer cam surface stop
radius 155, the cam 134 engaging the rocker arm assembly 136, which further
engages the ram assembly 60, maintains the at least one spring 90 in the charged state.
The cam 134 and the rocker arm assembly 136 are maintained in the charged
configuration by a latch assembly 180. The latch assembly 180 includes a latch lobe
182, a latch roller 184, latch prop 186 and a latch D-shaft 188. The latch lobe 182 is
fixed to the cam shaft 132 and maintains a specific orientation relative to the cam 134.
The latch roller 184 is rotatably coupled to the latch prop 186 and is structured to roll
over the surface of the latch lobe 182. The latch prop 186 has an elongated, generally
flat body 190 having a latch roller 184 mounting 192, a pivot point 194 and a latch
edge 196. The latch prop body 190 is pivotally coupled to a side plate 27 and is
structured to pivot, or rock, between a first position (Fig. 2A) and a second position
(Fig. 2B). In the first position, the latch edge 196 engages the outer diameter of the
latch D-shaft 188 and is held in place thereby. In turn, the latch roller 184 is held in

place against the latch lobe 182 and prevents the cam shaft 132 from rotating. The
latch D-shaft 188 is structured to rotate in response to a user input, e.g. actuation of a
solenoid (not shown). When the latch D-shaft 188 rotates, the latch edge 196 passes
over the latch D-shaft 188 as is known in the art. This allows the latch prop body 190
to move into the second position. When the latch prop body 190 is in the second
position, the latch roller 184 does not engage the latch lobe 182 and, due to the bias of
the at least one spring 90, as discussed above, the cam shaft 132 will rotate.
In this configuration, the closing assembly 54 operates as follows. For the
sake of this discussion the electrical switching apparatus 10 will be initially described
in the typical condition following an over current condition. That is, the at least one
pair of separable contacts 26 are in the first, open position, the pole shaft 56 is in the
first position, the toggle assembly 58 is in the first configuration, the ram body 94 is
in the first position and the at least one spring 90 is charged, and the rocker arm
assembly body 160 is in the first position. To close the at least one pair of separable
contacts 26, an operator actuates the latch assembly 180 to allow the latch D-shaft 188
to rotate as set forth above. When the cam shaft 132 is no longer retained by the latch
assembly 180, the cam 134 rotates slightly so as to allow the rocker arm body cam
follower 164 to fall over the step 156. When the rocker arm body cam follower 164
falls over the step 156, the rocker arm assembly body 160 is free to move to the
second position as the rocker arm body cam follower 164 now engages the outer cam
surface 150 at a point adjacent to the outer cam surface point of minimal radius 152.
At this point, the at least one spring 90 is no longer restrained and the at least one
spring 90 moves the ram body 94 from the first, retracted position toward the second,
extended position. As the ram body 94 moves from the first, retracted position toward
the second, extended position, the ram body forward surface 96 engages the toggle
joint 82 and causes the toggle assembly 58 to move from the first, collapsed
configuration to the second, over-toggle configuration. As noted above, the ram body
94 path of travel does not extend to the position of the toggle joint 82 when the toggle
assembly 58 is in the second, over-toggle configuration. Preferably, the ram body 94
moves with sufficient speed and energy so that, when the ram body 94 reaches the end
of the path of travel, the toggle assembly 58 is a few degrees over toggle but not at its
final over toggle resting point. Once the toggle assembly 58 is over the toggle point

by only a few degrees, the forces of the at least one spring 90 and whatever the
remaining momentum of the ram body 94 continue the motion of the toggle assembly
58 towards the second, over-toggle configuration, thereby creating a space between
the ram body forward surface 96 and the toggle joint 82.
As the toggle assembly 58 is moved into the second, over-toggle
configuration, the pole shaft 56 is also moved into its second position. As the pole
shaft 56 is moved into its second position, the at least one pair of separable contacts
26 are moved from the first, open position to the second closed position. At this point
the closing operation is complete, however, it is preferred that the operator again
engages the charging operator 130 to cause the cam 134 to rotate so that the outer cam
surface point of greatest radius 154 again engages the cam follower 164. As
described above, the rotation of the cam 134 to this position acts to charge the at least
one spring 90. Thus, the at least one spring 90 is charged and ready to close the at
least one pair of separable contacts 26 following another over current condition.
The toggle assembly 58 further includes a closing protection mechanism 200.
The closing protection mechanism 200 includes a control unit 202, a sensing switch
204, and a sensing switch actuator 206. The control unit 202, preferably, includes a
programmable logic circuit and is structured to receive a sensing switch signal and to
provide a control signal to the trip device 40. The control unit 202, shown
schematically, may be incorporated into the trip device 40, shown schematically. The
sensing switch 204 is coupled to, and in electronic communication with, the control
unit 202 and is structured to provide a sensing switch signal to the control unit 202.
The sensing switch 204 is disposed adjacent to the toggle assembly 58. The sensing
switch 204, preferably, has a housing 210 and an actuator member 212. The sensing
switch actuator member 212 is pivotally coupled to the sensing switch housing 210.
The sensing switch actuator member 212 is structured to pivot between a first,
unactuated position (Fig. *) and a second, actuated position (Fig. *). When the
sensing switch actuator member 212 is moved into the second, actuated position, the
sensing switch 204 generates the sensing switch signal and provides the sensing
switch signal to the control unit 202. The sensing switch actuator member 212 is
biased toward the first, unactuated position by a spring, a resilient member, or a
similar device (not shown).

The sensing switch actuator 206 is structured to actuate the sensing switch
204. That is, in the preferred embodiment, the sensing switch actuator 206 is
structured to engage and move the sensing switch actuator member 212 from the first,
unactuated position to the second, actuated position. In the preferred embodiment, the
sensing switch actuator 206 is a cam lobe 208 disposed at the first link outer end 74.
In this configuration, the sensing switch 204 is disposed adjacent to the pivot
point at the first link outer end 74. When the toggle assembly 58 is in the first,
collapsed configuration, the sensing switch cam lobe 208 does not engage the sensing
switch actuator member 212. Preferably, as the toggle assembly 58 moves into the in-
line configuration, the sensing switch actuator 206 initially engages the sensing switch
actuator member 212. Then, as the toggle assembly 58 moves into the second, over-
toggle configuration, the sensing switch actuator 206 moves the sensing switch
actuator member 212 from the first position to the second position. When the toggle
assembly 58 moves into the second, over-toggle configuration, the sensing switch 204
generates the sensing switch signal and provides the sensing switch signal to the
control unit 202. The control unit 202, in turn, provides the control signal to the trip
device 40.
In an alternate embodiment, shown in ghost in Figure 9, the sensing switch
204 is disposed adjacent to the stop pin 79. As noted above, the toggle joint 82 may
include a pin 84 extending generally perpendicular to the plane of each link 70, 72.
The sensing switch 204 may be structured to be actuated by the toggle joint pin 84 as
the toggle joint 82 moves into the second, over-toggle configuration. It is further
noted that the sensing switch 204 may be placed in any position wherein the sensing
switch actuator member 212 is engaged by an element of the toggle assembly 58 as
the toggle assembly 58 moves over toggle so long as the sensing switch 204 does not
interfere with the operation of the toggle assembly 58.
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 invention which is to be given the
full breadth of the claims appended and any and all equivalents thereof.

What is Claimed is:
1. A closing protection mechanism for an operating mechanism closing
assembly in an electrical switching apparatus, said electrical switching apparatus
having a housing assembly, operating mechanism, a trip device, and at least one pair
of separable contacts structured to move between a first, open position, wherein said
contacts are separated, and a second, closed position, wherein said contacts contact
each other and are in electrical communication, said operating mechanism closing
assembly having a pole shaft and a toggle assembly, said pole shaft coupled to said
separable contacts and structured to move said separable contacts between said first
position and said second position, said toggle assembly having a first link and a
second link, said first link having an outer end and an inner end, said second link
having an outer end and an inner end, said first link inner end and said second link
inner end rotatabley coupled to each other forming a toggle joint, said second link
outer end coupled to said pole shaft, said first link outer end coupled to said housing
assembly, said toggle assembly structured to move between a first, collapsed
configuration and a second, over-toggle configuration, passing through an in-line
configuration therebetween, said closing protection mechanism comprising:
a sensing switch coupled to said housing assembly and disposed adjacent to
said toggle assembly;
a sensing switch actuator disposed on said toggle assembly, said sensing
switch actuator structured to actuate said sensing switch; and
wherein said sensing switch structured to be actuated by said sensing switch
actuator when said toggle assembly is in said second, over-toggle configuration.
2. The closing protection mechanism of Claim 1 wherein said sensing
switch actuator initially engages said sensing switch when said toggle assembly is in
said in-line configuration.
3. The closing protection mechanism of Claim 1 wherein said sensing
switch actuator is disposed on said first link outer end.

4. The closing protection mechanism of Claim 3 wherein:
said sensing switch includes a housing and an actuator member, said actuator
member being pivotally coupled to said sensing switch housing; and
said sensing switch actuator is a cam lobe extending from said first link outer
end.
5. The closing protection mechanism of Claim 1 wherein said toggle
assembly includes a stop pin, said toggle joint structured to engage said stop pin when
said toggle assembly is in said second, over-toggle configuration, and wherein:
said sensing switch is disposed adjacent to said stop pin; and
said sensing switch actuator is disposed at said toggle joint.
6. An electrical switching apparatus comprising:
a housing assembly defining an enclosed space;
a plurality of side plates, said side plates disposed within said housing
assembly enclosed space, generally parallel to each other, said side plates having a
plurality of aligned openings therein whereby one or more elongated members may be
coupled, including rotatably coupled, perpendicular to and between adjacent side
plates;
at least one pair of separable contacts structured to move between a first, open
position, wherein said contacts are separated, and a second, closed position, wherein
said contacts contact each other and are in electrical communication;
an operating mechanism with a closing assembly having a pole shaft, and a
toggle assembly;
said pole shaft rotatably coupled between a pair of adjacent side plates, said
pole shaft further coupled to said at least one pair of contacts, wherein said pole shaft
rotates between a first position, wherein said separable contacts are in said first, open
position and a second position, wherein said separable contacts are in said second,
closed position;
said toggle assembly having first link and a second link, each link having a
first, outer end and a second, inner end, said first link and a second link rotatably
coupled together at said first link inner end and said second link inner end thereby

forming a toggle joint, said toggle assembly structured to move between a first,
collapsed configuration and a second, over-toggle configuration, said toggle assembly
structured to move between a first, collapsed configuration and a second, over-toggle
configuration, passing through an in-line configuration therebetween;
said second link inner end rotatably coupled to said pole shaft wherein when
said toggle assembly is in said first, collapsed configuration, said pole shaft is in said
first position, and when said toggle assembly is in said second, over-toggle
configuration said pole shaft is in said second position;
a closing protection mechanism including a sensing switch and a sensing
switch actuator;
said sensing switch coupled to said housing assembly and disposed adjacent to
said toggle assembly;
said sensing switch actuator disposed on said toggle assembly, said sensing
switch actuator structured to actuate said sensing switch; and
wherein said sensing switch structured to be actuated by said sensing switch
actuator when said toggle assembly is in said second, over-toggle configuration.
7. The electrical switching apparatus of Claim 6 wherein said sensing
switch actuator initially engages said sensing switch when said toggle assembly is in
said in-line configuration.
8. The electrical switching apparatus of Claim 6 wherein said sensing
switch actuator is disposed on said first link outer end.
9. The electrical switching apparatus of Claim 8 wherein:
said sensing switch includes a housing and a actuator member, said actuator
member being pivotally coupled to said sensing switch housing; and
said sensing switch actuator is a cam lobe extending from said first link outer
end.

10. The electrical switching apparatus of Claim 6 wherein:
said toggle assembly includes a stop pin, said toggle joint structured to engage
said stop pin when said toggle assembly is in said second, over-toggle configuration;
said sensing switch is disposed adjacent to said stop pin; and
said sensing switch actuator is disposed at said toggle joint.
11. A closing protection mechanism for an operating mechanism closing
assembly in an electrical switching apparatus, said electrical switching apparatus
having a housing assembly, operating mechanism, a trip device, and at least one pair
of separable contacts structured to move between a first, open position, wherein said
separable contacts are separated, and a second, closed position, wherein said separable
contacts contact each other and are in electrical communication, said trip device
structured to receive a control signal and perform a selected trip procedure in response
to said control signal, said operating mechanism closing assembly having a pole shaft
and a toggle assembly, said pole shaft coupled to said separable contacts and
structured to move said separable contacts between said first position and said second
position, said toggle assembly having a first link and a second link, said first link
having an outer end and an inner end, said second link having an outer end and an
inner end, said first link inner end and said second link inner end rotatabley coupled to
each other forming a toggle joint, said second link outer end coupled to said pole
shaft, said first link outer end coupled to said housing assembly, said toggle assembly
structured to move between a first, collapsed configuration and a second, over-toggle
configuration, passing through an in-line configuration therebetween, said closing
protection mechanism comprising:
a control unit coupled to, and in electronic communication with, said trip
device, said control unit structured to receive a sensing switch signal and to provide a
control signal to said trip device;
a sensing switch coupled to, and in electronic communication with, said
control unit, said sensing switch disposed adjacent to said toggle assembly, said
sensing switch structured to provide a sensing switch signal to said control unit;
a sensing switch actuator disposed on said toggle assembly, said sensing
switch actuator structured to actuate said sensing switch; and

wherein said sensing switch structured to be actuated by said sensing switch
actuator when said toggle assembly is in said second, over-toggle configuration.
12. The closing protection mechanism of Claim 11 wherein said sensing
switch actuator initially engages said sensing switch when said toggle assembly is in
said in-line configuration.
13. The closing protection mechanism of Claim 11 wherein said sensing
switch actuator is disposed on said first link outer end.
14. The closing protection mechanism of Claim 13 wherein:
said sensing switch includes a housing and a actuator member, said actuator
member being pivotally coupled to said sensing switch housing; and
said sensing switch actuator is a cam lobe extending from said first link outer
end.
15. The closing protection mechanism of Claim 11 wherein said toggle
assembly includes a stop pin, said toggle joint structured to engage said stop pin when
said toggle assembly is in said second, over-toggle configuration, and wherein:
said sensing switch is disposed adjacent to said stop pin; and
said sensing switch actuator is disposed at said toggle joint.
16. An electrical switching apparatus comprising:
a housing assembly defining an enclosed space;
a plurality of side plates, said side plates disposed within said housing
assembly enclosed space, generally parallel to each other, said side plates having a
plurality of aligned openings therein whereby one or more elongated members may be
coupled, including rotatably coupled, perpendicular to and between adjacent side
plates;
at least one pair of separable contacts structured to move between a first, open
position, wherein said contacts are separated, and a second, closed position, wherein
said contacts contact each other and are in electrical communication;

an operating mechanism including a closing assembly having a pole shaft, and
a toggle assembly;
said pole shaft rotatably coupled between a pair of adjacent side plates, said
pole shaft further coupled to said at least one pair of separable contacts, wherein said
pole shaft rotates between a first position, wherein said separable contacts are in said
first, open position and a second position, wherein said separable contacts are in said
second, closed position;
said toggle assembly having first link and a second link, each link having a
first, outer end and a second, inner end, said first link and a second link rotatably
coupled together at said first link inner end and said second link inner end thereby
forming a toggle joint, said toggle assembly structured to move between a first,
collapsed configuration and a second, over-toggle configuration, said toggle assembly
structured to move between a first, collapsed configuration and a second, over-toggle
configuration, passing through an in-line configuration therebetween;
said second link inner end rotatably coupled to said pole shaft wherein when
said toggle assembly is in said first, collapsed configuration, said pole shaft is in said
first position, and when said toggle assembly is in said second, over-toggle
configuration said pole shaft is in said second position;
a closing protection mechanism including a control unit, a sensing switch and
a sensing switch actuator;
said control unit coupled to, and in electronic communication with, said trip
device, said control unit structured to receive a sensing switch signal and to provide a
control signal to said trip device;
said sensing switch coupled to, and in electronic communication with, said
control unit, said sensing switch disposed adjacent to said toggle assembly, said
sensing switch structured to provide a sensing switch signal to said control unit;
said sensing switch actuator disposed on said toggle assembly, said sensing
switch actuator structured to actuate said sensing switch; and
wherein said sensing switch structured to be actuated by said sensing switch
actuator when said toggle assembly is in said second, over-toggle configuration.

17. The electrical switching apparatus of Claim 16 wherein said sensing
switch actuator initially engages said sensing switch when said toggle assembly is in
said in-line configuration.
18. The electrical switching apparatus of Claim 16 wherein said sensing
switch actuator is disposed on said first link outer end.
19. The electrical switching apparatus of Claim 18 wherein:
said sensing switch includes a housing and a actuator member, said actuator
member being pivotally coupled to said sensing switch housing; and
said sensing switch actuator is a cam lobe extending from said first link outer
end.
20. The electrical switching apparatus of Claim 16 wherein:
said toggle assembly includes a stop pin, said toggle joint structured to engage
said stop pin when said toggle assembly is in said second, over-toggle configuration;
said sensing switch is disposed adjacent to said stop pin; and
said sensing switch actuator is disposed at said toggle joint.

The closing protection mechanism provided herein includes a control unit, a
sensing switch and a sensing switch actuator. The control unit is coupled to, and in
electronic communication with, the trip device. The control unit is structured to
receive a sensing switch signal and to provide a control signal to the trip device. The
sensing switch coupled to, and in electronic communication with, the control unit.
The sensing switch is disposed adjacent to the toggle assembly. The sensing switch is
structured to provide a sensing switch signal to the control unit. The sensing switch
actuator is disposed on the toggle assembly. The sensing switch actuator is structured
to actuate the sensing switch. The sensing switch is structured to be actuated by the
sensing switch actuator when the toggle assembly is in the second, over-toggle
configuration.