Modular electrical switch and switching assembly for industrial elevators

A modular electrical switch provides a wiping or shearing action upon closing and opening thereof. A contact carrier disposed within a housing linearly carries a movable contact into engagement with a stationary contact. The contact carrier is guided by movable slide plates disposed on either side thereof and movable along with the contact carrier as a contact assembly. The guide plates also provide pivot recesses for pivot bosses of the contact carrier. The contact carrier is constrained to linear motion up to the point of contact between the movable contact and the stationary contact by a cam trace in the housing. After contact between the movable contact and the stationary contact, the contact carrier reaches a pocket defined by the cam trace, ceases linear movement and upwardly pivots to provide a wiping action between the movable contact and the stationary contact. Immediately upon reversed, pivoting and linear motion of the contact carrier a shearing action is provided between the movable contact and the stationary contact. A plurality of such modular switches are utilized in a freight elevator interlock system for regulating the opening and closing of the various doors and carriage of the freight elevator. A common sliding actuator controls the modular switches regardless of the orientation of the respective switches within the housing.

FIELD OF THE INVENTION 
The present invention relates generally to electrical switches and to 
switching assemblies utilizing such electrical switches in connection with 
freight elevators and, more particularly, to electrical switches of the 
wiping action type and switching assemblies utilizing the same to control 
the opening and closing of freight elevator gates and doors. 
BACKGROUND OF THE INVENTION 
Freight elevators which are used in warehouses, commercial buildings, and 
various industrial applications, differ from general purpose or passenger 
elevators in several respects. Although the actual carriage or car of both 
types of elevators are essentially the same, neglecting the size and decor 
thereof, the doors, and mechanisms for the operation of the doors to the 
elevator differ. Furthermore, freight elevators are generally subject to 
different codes and regulations. 
Generally, passenger elevators have two sets of horizontally-opening doors. 
One set of doors moves with the elevator carriage while the other set of 
doors is fixed to the hoistway opening on the respective floor. Both sets 
of doors include left and right halves that join together along a vertical 
line and thus horizontally outwardly open. When the passenger elevator 
carriage reaches the respective floor, both sets of doors then open to 
allow passengers to enter and egress. 
In contrast, freight elevators generally have vertically opening doors. The 
vertically opening doors may be either a single set of doors affixed to 
the hoistway opening of the respective floor or a single vertically 
opening door. The single set of vertical doors includes two half doors 
meeting at a horizontal line and respectively opening in a vertical 
bi-directional manner while the single door moves vertically. The elevator 
carriage generally includes a single vertically-moving gate or door which 
travels along with the elevator carriage. Both the passenger elevators and 
freight elevators include systems therein which control the opening and 
closing of the respective doors. Various regulations and safety codes 
require that such doors positively open and close. 
In the case of freight elevators, safety codes require that the doors to 
the hoistway physically lock when the elevator is not present at the 
particular floor. Therefore, all of the doors to the hoistway need to be 
locked when the elevator is in motion. When the elevator stops at any 
individual floor, then, and only then, should the particular set of doors 
to the that particular floor be able to open. This is generally 
accomplished by providing a positive locking mechanism at each floor that 
is also electrically interlocked so that in the case of some possible 
action that would unlock a door at a particular floor which should not be 
unlocked, the elevator carriage will stop and no other action may take 
place. Such prior art locking mechanisms are thus located at each floor. 
It is necessary for the contacts in the safety circuit to positively open 
when needed and freight elevators are generally located in areas which are 
not always clean, or are subject to becoming dirty quickly, with loading 
and unloading of various equipment and the like. In this regard, European 
safety codes specify that such contacts must open even if they are welded 
shut. 
Most prior art interlock systems utilize spring action to positively make 
contact or "interlock" and another force or positive mechanism is used to 
break contact. However, such positive mechanisms are not capable of 
providing the necessary shearing action that may be required to separate 
the contacts should the contacts become joined together either through 
welding or the like. Thus, it is desirable to have an interlock system 
which is capable of positively making and breaking contact in all 
situations. 
Furthermore, prior art interlock systems or ladder switches are composed of 
many individual components. If it is necessary to repair or change the 
components due to breakage or corrosion the entire assemblage must be 
taken apart. Due to the general location of the interlock system within 
the elevator hoistway, it is generally very difficult to reach and/or 
effect the modifications. 
It is thus desirable to provide an interlock switch which is easy to effect 
repair. 
SUMMARY OF THE INVENTION 
The present invention addresses the problems and concerns of the prior art 
by providing an electrical switch that creates a wiping action of the 
contacts during initial contact and during the opening of the switch. Such 
wiping action is accomplished by a pivoting motion of a sliding contact 
carrier that only occurs after initial connection of the contacts. The 
return of the sliding contact carrier provides a wiping, shearing, or 
breaking motion during reverse pivoting after initiation of contact 
breaking. 
The movable contact carrier assembly includes a cam and pivot that are 
guided by slide plates disposed on either side of the contact carrier. 
Each slide plate includes a pivot recess to allow the contact carrier to 
pivot. The contact carrier includes a pair of pivot bosses received in the 
pivot recesses. The pivoting motion of the contact carrier is initially 
constrained by a cam trace on the upper housing. The cam trace defines a 
pocket at the end of the trace. As the contact carrier is moved forward 
into the contact position, the contact carrier is constrained to linear 
movement by the cam trace. At the point of contact of the movable contact 
with the stationary contact, the contact carrier is caused to pivot 
upwardly into the pocket defined at the end of the cam trace. The movable 
contact, carried by the contact carrier, thus moves transverse to the 
initial direction of movement of the contact carrier, or upwardly against 
the stationary contact to provide the wiping action. 
Upon opening or breaking contact, the contact carrier reverses its path to 
provide a shearing action of the movable contact against the stationary 
contact. Once the contact carrier is clear of the pocket in the cam trace 
the downward movement of the movable contact relative to the stationary 
contact ceases, and transverse motion begins. A spring assists in 
maintaining contact pressure between the movable contact and the 
stationary contact upon closure. 
In one form thereof, the present switch comprises a housing, a stationary 
contact disposed in the housing, a movable contact disposed in the 
housing, and a contact carrier. The contact carrier carries the movable 
contact into and out of electrical engagement with the stationary contact, 
the housing defining a path of travel along which the contact carrier 
moves. Means for pivoting the contact carrier at a point of contact of the 
movable contact with said stationary contact is provided to effect a 
wiping action between the movable contact and the stationary contact. 
In another form there is provided an electrical switch comprising, a 
housing having an upper portion and a lower portion with the upper and 
lower portions joining at a horizontal plane. A first stationary contact 
is disposed in the housing, and a second stationary contact is disposed in 
the housing and spaced from the first stationary contact. A two-ended 
movable contact and a contact carrier are movably disposed in the housing. 
The contact carrier is adapted to carry the two-ended movable contact into 
and out of electrical engagement with the first and second stationary 
contacts to complete an electrical circuit therebetween. The contact 
carrier includes a leg extending from the lower portion of the housing for 
receiving an actuating thrust. The housing defining a path of travel along 
which the contact carrier linearly moves. Further included is means for 
pivoting the contact carrier after a point of contact of the two-ended 
movable contact with the first and second stationary contacts to effect a 
wiping action between the two-ended movable contact and the first and 
second stationary contacts. The pivoting means includes a first and second 
boss integrally formed on opposite sides of the contact carrier, and a 
first and second guide plate disposed on opposite sides of the contact 
carrier. The first and second guide plates respectively having a first and 
second pivot recess for receiving the first and second bosses such that 
the contact carrier is pivotally disposed thereon. A cam trace is disposed 
in the path of travel and formed in a lower surface of the upper portion, 
the cam trace defining a recess at an end of the travel path and 
constraining the contact carrier from pivotal movement until the contact 
carrier has reached a predetermined travel distance. The actuating thrust 
linearly moves the contact carrier along the path of travel such that the 
two-ended movable contact engages the first and second stationary contacts 
at the predetermined travel distance wherein the contact carrier ceases 
linear movement, the recess then permitting the contact carrier to pivot 
to effect a wiping action between the two-ended movable contact and the 
first and second stationary contacts. 
In another form of the invention, the present invention provides an 
interlock assembly for freight elevator doors that incorporates an array 
of the present modular electrical switches. The modular switches are 
mounted within a housing and are actuated by a common sliding actuator in 
response to a cam drive. Movement of the common sliding actuator provides 
an off-center or external thrust that is transferred to the switch.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Prior Art 
Referring now to FIGS. 1-4 there is shown a prior art ladder switch 
generally designated 30 of the type currently being utilized in the 
freight elevator industry to operate the associated gates and doors, 
currently constituting the state of the art in the industry. Ladder switch 
30 includes an elongated mounting board 32 having four spaced apart holes 
34a-d that permit mounting board 32 switch assemblies 36, 37, 38, 39, 40, 
41, are secured to mounting board 32 longitudinally adjacent to one 
another. An elongated, slidable actuator rod 44 is centrally positioned 
onto mounting board 32 and removably constrained to longitudinal movement 
thereto by two clip assemblies 46, 48. As more easily perceivable by 
reference to FIG. 3, clip assemblies 46, 48 each consist of a respective 
bracket 47, 49, secured to mounting board 32 via nut and bolt pairs, 50, 
51, and 52, 53. Each bracket 47, 49 respectively includes two spaced 
apart, upstanding flanges 54, 55, and 56, 57, each flange 54-57 having a 
bore therethrough (not shown). 
Received between flange pairs 54, 55 and 56, 57, are respective U-brackets 
58, 60 that are secured thereto by respective cotter pins 66, 68. Sliding 
actuator rod 44 is thus slidably received within U-brackets 58, 60 which 
also function as a retainer for sliding actuator rod 44 such that sliding 
actuator rod 44 may limitedly longitudinally travel back and forth 
therein. U-brackets 58, 60 also provide a bearing surface for sliding 
actuator rod 44. 
As best discerned in FIGS. 3 and 4, a movable contact portion of each 
switch assembly 36-41 is disposed on sliding actuator rod 44. Disposed on 
one end of sliding actuator 44 is an end cap 70 secured thereto by a pin 
72 that extends through end cap 70 and sliding actuator rod 44. End cap 70 
provides the interface with other mechanisms when the elevator approaches 
and stops at the desired floor, to move sliding actuator rod 44 
accordingly. The movable contact portion of switch assembly 36 essentially 
consists of a two-ended contact 78a that is longitudinally movable back 
and forth on sliding actuator rod 44. However, the longitudinal travel 
distance of two-ended contact 78a is limited. A tubular sleeve 74a is 
disposed on one axial end of two-ended contact 78a. Tubular sleeve 74a is 
removably secured to sliding actuator rod 44 by a cotter pin 76a that 
extends through diametrically opposed bores (not shown) in tubular sleeve 
74a and bore 84a in sliding actuating rod 44. Two-ended contact 78a thus 
abuts one end of tubular sleeve 74a such that tubular sleeve 74a provides 
a stop or limiter therefor. Two-ended contact 78a is resiliently limited 
on the other axial end by a spring 80a, a spring retainer cup 82a, and a 
tubular sleeve 74b. Tubular sleeve 74b is removably secured to sliding 
actuator rod 44 by a cotter pin 76b that extends through diametrically 
opposed bores (not shown) in tubular sleeve 74b and bore 84b in sliding 
actuating rod 44. Spring 80a along with spring retainer cup 82a are 
disposed between two-ended contact 78a and tubular sleeve 74b such that 
two-ended contact 78a may compressingly longitudinally travel in one 
direction on sliding actuator 44. This creates a biasing force against 
two-ended contact 78a when two-ended contact 78a engages right and left 
contact assemblies 86a and 87a, respectively (see FIG. 1). 
Likewise, the movable contact portion of switch assemblies 37-41 include 
respective two-ended contacts 78b-f that are disposed between respective 
tubular sleeves 74c-h, springs 80b-f, and spring retainers 82b-f. In the 
same manner as described above, tubular sleeves 74c-h are removably 
secured to sliding actuator rod 44 via respective cotter pins 76b-h which 
extend through diametrically opposed bore (not shown) in the respective 
tubular sleeve, and respective bores 84b-h in sliding actuator rod 44. 
Furthermore, each two-ended contact 78b-f is limitedly longitudinally 
movable along sliding actuator rod 44, this being accomplished by abutting 
the respective tubular sleeve, and resiliently biased by the respective 
spring on the other end. 
Each movable contact portion of switch assemblies 36-41 is movable into and 
out of engagement with the stationary contact portion of switch assemblies 
36-41, respectively constituting stationary contact pairs, 86a/87a, 
86b/87b, 86c/87c, 86d/87d, 86e/87e, and 86f/87f, thereby completing the 
electrical circuit therebetween. As best seen in FIGS. 3 and 4, each 
stationary contact, 86a-f, and 87a-f, respectively, includes an associated 
electrical lead 88a-f, and 89a-f, for connection to the other various 
components associated with the control of freight elevators. It should 
here be appreciated that it is not necessary for all of the switch 
assemblies 36-41 to be open or closed at the same time, as the function of 
each respective switch assembly may dictate that some be open while at the 
same time others be closed, and vice versa. 
In short, ladder switch 30 operates through the sliding of actuator rod 44. 
When the actuator rod 44 is in the position depicted in FIG. 1, only the 
top switch assembly 36 is closed, while the other switch assemblies 37-41 
are open. The sliding of actuator rod 44 as depicted in FIG. 2 opens 
switch 36 while at the same time closing switches 37-41. 
Thus, it can be appreciated from the foregoing that the prior art ladder 
switch 30 is quite impractical in several respects. Since the ladder 
switch is mounted in the hoistway of the elevator, it is not only 
difficult to reach, but even more difficult to effect repairs. Should a 
contact become welded, corroded, or otherwise, thereby necessitating the 
replacement thereof, the entire sliding actuator rod 44 must be initially 
removed. This is accomplished by first removing U-brackets 58, 60. Each 
tubular sleeve must then be removed until the nonoperative contact is 
reached. Obviously, springs, cotter pins, tubular sleeves, and spring 
retainers have been removed and must be retained for reassembly. It is 
therefore difficult and tedious to effect repairs of current state of the 
art, prior art ladder switches. Thus, in many cases the entire sliding 
actuating rod and switch assemblies contained thereon is replaced, making 
such repair more costly than need be. 
PRESENT EMBODIMENT 
Referring now to FIGS. 5-9 there is shown an industrial or freight elevator 
interlock switch assembly generally designated 100 according to the 
present invention. It should be appreciated that interlock switch performs 
the function of the prior art ladder switch, and is placed within the 
elevator hoistway at each floor at which the elevator stops. The interlock 
assembly 100 is mechanically connected to the elevator doors and carriage 
to monitor the position of each, and electrically connected to the motors 
that operably drive the elevator doors and carriage. Thus, interlock 
assembly 100 monitors the position of the doors and carriage such that the 
carriage will not be able to move when the doors are not closed and 
locked, but allows operation of the carriage when the doors are locked. 
Interlock switch 100 includes an elongated housing 102 preferably formed 
of a metal such as steel. Housing 102 defines an elongated or longitudinal 
channel 103 (see FIG. 8) in which is disposed an elongated or longitudinal 
actuator plate 104 preferably formed of a glass-filled plastic. Disposed 
at one end of housing 102 is a cam 108 which is secured to and pivotable 
about a rotating rod 110 by a pin (not shown). 
Specifically referring to FIG. 8, a longitudinal view of housing 102 is 
shown with all of the modular switches removed for clarity. Channel 103 is 
defined by an interior longitudinal, generally U-shaped wall 230 that 
extends along the longitudinal length of housing 102. Wall 230 includes 
two integrally formed longitudinally extending bosses 232 and 234 onto 
which the modular switches are mounted. By elevating the modular switches, 
this allows the carrier legs 114 to freely extend into the actuator plate 
104 such that the actuator plate 104 mechanically mates with the carrier 
legs 114 for actuation of the modular switches by the actuator plate 104. 
A bore 238 that may be threaded is located in end wall 236. Bore 238 thus 
allows assembly 100 to be mounted onto a conduit (not shown) and/or permit 
electrical wires or leads (not shown) to connect to and from the modular 
switches. 
Rotating rod 110 is connected to an elevator door actuating mechanism such 
that when the freight elevator moves to the desired floor, at a certain 
point in time dictated by the position of the elevator carriage, rod 110 
is rotated, thereby causing cam 108 to pivot thereabout. Rod 110 is 
bi-directional, such that as the elevator carriage arrives and stops at 
the desired floor and the doors are ready to open, rod 110 rotates in one 
direction, thereby pivoting cam 108 in the same rotative sense, while when 
the elevator carriage is ready to leave the floor and the doors are shut, 
rod 110 rotates in the opposite direction thereby pivoting cam 108 in the 
same opposite rotative direction. Actuator plate 104 includes a stepped 
portion or cam recess 106 into which cam 108 extends. Thus, as cam 108 
pivots in response to actuator rod 110, actuator plate 104 is limitedly 
longitudinally movable back and forth within channel 103, controlled by 
the limited pivotal movement of cam 108. FIG. 6 depicts cam 108 and 
actuator plate 104 in a fully extended position, which is a door unlocked 
position that allows the doors to operate but does not allow the carriage 
to move. When cam 108 is rotated the opposite direction, cam 108 slides 
actuator plate 104 downwardly, as viewed in the drawings. This position 
would indicate that the doors are shut and locked, so the carriage is 
operable and able to move to the desired floor. FIG. 5 depicts cam 108 and 
actuator plate 104 in a mid-stroke position. 
Actuator plate 104 further includes seven stepped portions or carrier leg 
recesses 112a-g, longitudinally spaced therealong. Disposed above recesses 
112a-g are seven modular switches 116a-g in accordance with another aspect 
of the present invention. It should here be appreciated that the plurality 
of modular switches are all identical in form, function, and operation. 
Thus, although each part of each modular switch has a different number in 
the Figures, this is only for differentiation of each modular switch and 
for clarity for the reader. Each modular switch 116a-g is mounted to 
housing 102 by screws or other suitable mounting devices such that the 
switches straddle channel 103 and thus actuator plate 104. Referring 
particularly to FIG. 9, Switches 116b and 116f are shown removed from 
housing 102 with their associated mounting screws 118a,b, and 118c,d, 
respectively, likewise removed to show. 
Extending into each recess 112a-g from each switch 116a-g is a carrier leg 
114a-g respectively. As detailed hereinbelow, the carrier leg moves within 
the switch to cause the internal contacts within the switch to meet and 
break (open and close). Thus, as actuator plate 104 moves in response to 
cam 108 in response to the position and status of the elevator doors and 
carriage, so do the respective carrier legs 114a-g such that contact is 
either made or broken in the respective modular switch 116a-g. 
As can be seen in FIGS. 5-7, 9, switch 116a is oriented opposite to the 
other switches 116b-g. This is because switch 116a is the main interlock 
switch that controls elevator operation by locking out all elevator 
operation if the doors are unlocked. Thus, although switches 116b-g 
control the motors that drive the doors and are open circuited as shown in 
FIG. 6, such that the same motors will not operate, switch 116a is close 
circuited, enabling operation of the carriage. 
Interlock assembly 100 further includes an additional independently 
actuated switch 126 having a carrier leg 124 disposed within a recess 123 
formed in second actuator plate 122. Actuator plate 122 is connected to a 
cam that moves in response to the upper door of the bi-parting doors. As 
it could be possible for someone to try to pry open the top panel, the 
switch thus monitors the same. 
The present interlock assembly 100 with its modular switch array, thus 
makes the replacement of defective switches much simpler and easier, 
regardless of the mounting location or environment of the assembly. Two 
mounting screws are removed to extricate any defective switch which can 
then be just as easily replaced. Furthermore, as described hereinbelow, 
the modular switches include a housing which protects the contacts within 
the switch from degradation as a result of corrosion, deposits, and the 
like. 
A modular switch 130 is depicted in FIG. 10 which is identical to the 
modular switches 116a-g, 126 shown in FIGS. 5-7, 9 and discussed 
hereinabove with reference to the interlock assembly. Switch 130 includes 
an upper housing member 132 and a lower housing member 134 which are 
joined together along an essentially horizontal line. On one side of the 
outer surface of upper housing member 132 is a raised portion 136 which 
includes a rectangular opening 137, while disposed on the other side of 
upper housing member 132 is another raised portion 138 which includes a 
rectangular opening 139. Rectangular openings 137, 139 permit connection 
of an electrical lead (not shown) to the stationary contacts disposed 
within the housing. Lower housing member 134 includes a rectangular screw 
boss 140 having a bore 141 therethrough for mounting one end of switch 
assembly 130 via a screw. Diagonally disposed of rectangular screw boss 
140 is another rectangular boss 142 having a bore 143 therethrough for 
mounting the other end of switch assembly 130. An actuating or carrier leg 
154 is shown extending from the underside of lower housing 134. 
Upper housing member 132 is depicted in greater detail in FIGS. 22-25. FIG. 
22 shows a top view of upper housing member 132. Adjacent rectangular 
openings 137, 139 are holes 145, 151 respectively, though which one can 
tighten wire binding screws, of which only one wire binding screw 144 is 
shown (see FIGS. 10, 26) in order to securely connect the electrical lead 
(not shown) to the stationary contact, of which only one stationary 
contact 148 is shown (see FIGS. 10, 26). With reference to FIG. 26, the 
connection of an electrical lead is accomplished by inserting an 
electrical lead (not shown) into opening 137 until the electrical lead is 
positioned under wire binding screw head 144 and clamp member 146. Wire 
binding screw 144 is threadedly engaged with stationary contact 148. Wire 
binding screw 144 is then tightened by inserting an appropriate 
screwdriver into hole 145 and rotating. Although the opposite side 
stationary contact is not shown, it is identical to the configuration 
depicted in FIG. 26 and connected in the same manner. 
Additionally referring now to FIG. 24, upper housing member 132 includes 
two elongated walls 202, 203 that define an upper surface of a channel or 
travel path cavity 186. At both ends of walls 202, 203 are flanges 196, 
197, 198, 199, which provide a locking mechanism to join with the lower 
housing member 134. Disposed in travel path cavity 186 and extending 
downwardly from the lower or underside surface of upper housing member 132 
is a cam trace 176 defined by three ledges 178, 179, 180. Ledges 178, 179, 
180 are also depicted in FIGS. 23, 25, and such ledges define a pocket or 
recess 168 between the ends of ledges 178, 179,180, and the end of upper 
housing member 132. 
Referring now to FIGS. 18-21 lower housing member 134 is shown. Defined 
within front end wall 204, rear end wall 205, side wall 206, and side wall 
207 is the longitudinal travel path 186 for contact carrier 150 and slide 
plates 166, 182. It should here be appreciated that contact carrier 150, 
movable contact 162, and slide plates 166, 182 (see FIG. 30) constitute a 
movable contact assembly that travels within the longitudinal travel path 
cavity/channel 186. On the lower portion of lower half 134 below travel 
path cavity 186 is a cutout portion 187 through which leg 154 of contact 
carrier 150 extends. Disposed on both sides of cavity/channel channel 186 
are spaces 192, 193 in which the movable contact 162 travels. Referring to 
FIG. 30 movable contact 162 is shown transversely extending from contact 
carrier 150 as both are disposed within the housing. 
As best seen in FIG. 19 walls 204, 205 terminate in prongs 188, 189 that 
define respective surfaces 210, 212. When upper housing half 132 is to be 
joined with lower housing half 134, stepped edge 218 is inserted under 
prong 189. The union of upper housing half 132 with lower housing half 134 
is best seen in any one of FIGS. 12-17. Angled edge 216 is then forced 
downwardly onto prong 188 which rides up angled edge 216 to rest thereon. 
Thus, a snap-fit holds the two housing halves together. 
Reference now being made to FIG. 11, a contact carrier 150 together with 
slide plates 166, 182 are slidingly disposed within both upper and lower 
housing members 132,134. Contact carrier 150 is shown alone in FIG. 29 and 
is preferably fabricated from a plastic and includes a leg 154, two round 
pivot bosses, of which only one pivot boss 152 is shown, a rectangular 
opening 160 in which extends a finger 174, and an upwardly extending 
flange 158. Disposed on either side of contact carrier 150 is a slide or 
guide plate 166 of which only a small portion of one slide plate 166 is 
shown in FIG. 10. Referring to FIG. 28, the slide plate 166 is shown which 
is identical to slide plate 182. Essentially, slide plate 166 is 
rectangular in shape and of nominal thickness, fabricated preferably from 
a plastic. Slide plate 166 includes a round pivot bore or recess 172 and a 
rectangular opening 167. The pivot boss 152 of contact carrier 150 is 
pivotally disposed within recess 172, with one on either side of contact 
carrier 150. Opening 167 of slide plate 166 corresponds to rectangular 
opening 160 in contact carrier and is provided to permit movable contact 
162 to transversely extend therethrough (see FIG. 30). Finger 174 extends 
through an opening (not shown) in movable contact 162 to thereby hold 
movable contact 162 in place. FIG. 27 depicts contact carrier 150 in the 
fully closed position relative to cam trace 176 and upper housing 132. 
Referring back to FIG. 11, movable contact 162 with contact pad 163 is 
shown extending though opening 160. A spring 164 engages the rear of 
movable contact 162 and extends therefrom to contact carrier 150. 
Stationary contact 148 downwardly extends from the underside surface of 
upper housing 132 at one end and includes a contact pad 149. FIG. 11 
depicts contact carrier 150 in a fully closed position wherein the wiping 
action has already taken place. Spring 164 maintains a resilient bias of 
movable contact 162 towards stationary contact 148 as contact carrier 150 
continues to linearly and pivotably move. 
Operation 
The manner of operation of the present switch 130 will now be described 
with reference to FIGS. 12-17. Although switch 130 includes two stationary 
contacts disposed therein, one on either side of contact carrier 150 
(reference FIG. 10) and an elongated, movable contact that extends 
transversely from contact carrier 150 (see FIG. 30) thus stretching from 
one stationary contact to the other stationary contact to complete the 
circuit when closed, FIGS. 12-17 only shows one side of contact. This is 
because the other side of contact and operation thereof are identical and 
simultaneous since movable contact 162 which is supported and carried by 
contact carrier 150, extends transverse to contact carrier 150 and the 
longitudinal direction of travel thereof. 
FIG. 12 shows contact carrier 150 in a fully open position. Leg 154 is 
slightly rearwardly angled as contact carrier 150 is slightly forwardly 
angled, but cam trace 176 keeps flange 158 of contact carrier 150 and thus 
the entire contact carrier 150 in the proper attitude. This allows contact 
carrier 150 to smoothly linearly travel within the housing. Movable 
contact 162 with contact pad 163 is forwardly biased within opening 160. 
FIG. 13 depicts the initiation of forward movement as a result of a force 
exerted against the rear of leg 154 as indicated by the thick arrow. This 
is deemed the pre-travel stage before any contact between movable contact 
162 and stationary contact 148. The motion of contact carrier 150 is 
linear, in that cam trace 176 (see FIG. 27) prevents any upwardly pivoting 
movement at this point. It should be noted that the guide plates, of which 
only one guide plate 166 is shown, linearly travels along with contact 
carrier 150. Thus as noted above, the entire contact assembly moves as 
force is exerted against leg 154. 
FIG. 14 depicts the initial contact stage between contact pad 163 of 
movable contact 162 and contact pad 149 of stationary contact 148. At this 
point the top portion of contact pad 163 abuts the lower portion of 
contact pad 149. 
FIG. 15 depicts the initial wiping of movable contact 162 and stationary 
contact 148 wherein the upper surface of contact pad 163 of movable 
contact 162 abuts the lower surface of contact pad 149 of stationary 
contact 148. At this point, contact carrier 150 has linearly traveled, 
while at the same time starting a 3.degree. wipe of contact pad 149 of 
stationary contact 148 by contact pad 163 of movable contact 162. 
FIG. 16 depicts the continuation of the wiping action. Contact carrier 150 
at this point has further linearly traveled. Flange 158 has also reached 
the end of cam trace 176. Because of the off-center thrust applied to leg 
154, contact carrier 150 tends to want to rotate or pivot about its pivot 
bosses 152. Previously, because flange 158 has abutted cam trace 176, 
contact carrier 150 could not pivot but was constrained to linear 
movement. Since pocket or recess 168 is at the end of cam trace 176, and 
flange 158 has reached that point, contact carrier 150 now starts to 
upwardly pivot upon continued application of off-center thrust. It is also 
at this point that guide plates 166 abut stop 170 and prevents any further 
linear travel of contact carrier 150. This preliminary pivoting causes an 
additional 3.degree. wipe for a total of a 6.degree. wipe. During this 
time, movable contact 162 cannot linearly travel any further, as it is 
abutting stationary contact 148. However, spring 164 compresses against 
movable contact 162 such that contact carrier 150 may continue its 
linear/pivotal travel. 
FIG. 17 depicts the final stage wherein contact carrier 150 is constrained 
against linear movement and must pivot under continued application of 
off-center thrust to leg 154. Contact carrier 150 travels another short 
linear distance before flange 158 fully enters recess 168 to abut the 
upper surface of recess 168 which then stops the pivoting of contact 
carrier 150. This motion causes a final 6.degree. wiping action of contact 
pad 163 against contact pad 149 for a 12.degree. total wipe. 
Application of thrust in the reverse linear direction causes the contact 
carrier assembly to follow the reverse path of movement to that described 
above with reference to FIGS. 12-17. The reverse application of thrust 
creates a shearing action between contact pad 163 of movable contact 162 
and contact pad 149 of stationary contact 148 to additionally wipe the 
contacts and unstick the contacts. 
In the case of interlock assembly 100, as shown in FIGS. 5-8 and described 
hereinabove, actuator plate 104 acting through actuator rod 110 and cam 
108, provides the external or off-center thrust for actuating modular 
switches 116a-g regardless of the orientation of the switches. 
While the foregoing is directed towards the preferred embodiment of the 
present invention, other and further embodiments of the invention may be 
devised without departing from the basic scope thereof, and the scope 
thereof is determined by the claims which follow.