US2388342A - Electric switch - Google Patents

Description

Nov. 6 1945. c. A. S-CHAEFER ELECTRIC SWITCH- Filed May 6, 1943 2 Sheets-Sheet l INVENTOR Gar? gSczqe/ 1 ATTORNEY Nov. 6, 1945. c. A. SCHAEFER ELECTRIC SWITCH Filed May 6, 1943 2 Sheets-Sheet 2 INVENTOR fer a? M v ATTORNEY CW2 Baez Patented Nov. 6, 1945 ELECTRIC SWITCH Carl A. Schaefer, Whitefish Bay, Wis, assignor to Square D Company, Detroit, Mich, a corporation of Michigan Application May 6, 1943, Serial No. 485,795

13 Claims.

This invention relates to electric switches and more particularly to electric switche enclosed within a housing having a movable cover.

One object of the present invention is to provlde an enclosed switch having means for normally releasably holding the cover closed.

Another object of the present invention is to provide an enclosed switch wherein the cover cannot be opened while the switch is closed.

Another object of the present invention is to provide an enclosed electrical switch having an improved form of interlocking mechanism.

Another object of the present invention is to provide an enclosed switch wherein the interlockin mechanism includes means operative to move the switch handle to on position.

Another object of the present invention is to provide in an enclosed switch, latching means for releasably holding the cover to the enclosure and means operative on the latching means to prevent movement thereof, the latter means at the same time being operative to lock the operating handle in its 01f position.

Another object of the present invention is to provide an enclosed switch having means thereon adapted to support a padlock at a plurality of positions, the padlock when occupying a first position being effective to maintain the cover closed while permitting normal operation of the manual handle, and when mounted at a second position being adapted to lock the'cover closed and the manual handle in off position.

Other objects and features of the invention will be readily apparent to those skilled in the art from the specification and appended drawings illustrating certain preferred embodiments in which:

Figure l is a perspective view of a switch cabinet embodying the improvements of the present invention. 1

Figure 2 is an elevational view of the lower end of the switch cabinet of Figure 1 and showing the latching means in cover locking position.

Figure 3 is a fragmentary sectional view taken on the line III-4H of Figure 2.

Figure 4 is a fragmentary sectional view taken on the line IV-IV of Figure 3.

Figure 5 is a fragmentary sectional View taken along the line VV of Figure 4 and showing the latching means which normally releasably main tain the cover closed.

Figure 6 is a view similar to Figure 2, but showing the latching means moved to unlocking position wherein the cover may be moved to open position.

Figure 7 is an end elevational view of the switch cabinet but showing the end opposite to that illustrated in Figure 2.

Figure 8 is a fragmentary sectional view taken on the line VIII----VIII of Figure 7.

With reference to the drawings, the invention comprises a rectangular box-like sheet metal casing or cabinet l having a cover 2 cooperating therewith. The cover 2 is of a generally pan shape and is adapted to embrace the edges of the casing i and eiiect a close fit therewith. One end 5 of the cover 2 is pressed inwardly as at 6 and i to project into the cabinet I, as seen in Figures 7 and 8, and the projections 6 and l are adapted to be fitted into corresponding depressions 8 provided near the top of upper wall 9 of the casing l. Projections 6 and 1 fitting into depressions 8 prevent the cover 2 from being removed from the casing I with a rectilinear forward movement but rather the cover 2 must be rotated first about the pivots afforded by the projections 6 and "l and their corresponding depressions 8 before the cover 2 can be completely removed from the casing The top surface ll of the cover 2 is provided with a rectangular opening 12, through which is adapted to extend an oscillating operating handle l3 of an electric switch which is not shown since it forms no part of this invention, but which may be of any type provided it utilizes an oscillatin operating handle to effect the operation thereof. The operating handle i3 is formed of molded insulating material and is movable into two predetermined positions of rest to effect the operation of the electric switch, and has the outer surface thereof marked with the indicia On and 01f to indicate whether the contacts of the electric switch to be controlled are in engaged or disengaged positions. The top surface of the operating handle I3 is provided with a recess H) to provide for ease of manual movement of the handle between on and off positions, The handle I3 is so formed that but one of the indicia will be exposed to view at a time. Movement of the handle l3 counter-clockwise from the position of Figure 1 will carry the Word Ofi out'of sight and will bring the word On into view and thus the condition of the switch is readily apparent. The operating handle 13 has a projection l4 formed integral therewith and extending from a surface 15 disposed below the top surface of the cover 2, and. which serves a purpose to be hereinafter fully described.

To normally releasably secure the cover 2 to casing I, there i provided within the cover 2 and upon the lower end wall I6 thereof, a latching element I1. The latch I'I includes a cylindricalshaped projection I8 which extends into an opening in the cover 2 to provide a pivotal mounting for the latch IT. A rectangular-shaped portion I9 extends from the face of the cylindrical projection I8. A releasing member 2| which serves as an actuator for the latch I1 is disposed at the exterior of the cover 2 and upon the lower end wall I6 thereof. The releasing member 2| is provided with a rectangular-shaped opening therethrough which is adapted to receive the rectangular-shaped projection I9, which projection I9 effects a support for the actuating member 2|. With this assembly, the actuating member 2| and the latch I1 will move as a unit so that application of force to the actuating member 2| to move it will effect movement of the latch H. A cotter pin 22 is forced through an opening provided in the rectangular projection l9 and maintains the actuating member 2| and the latch I I in assembled relationship and prevents their accidentally coming loose. A flanged member 23 is welded to the outside of the lower end wall I6 of cover 2 and spaces the actuating member 2| from the end wall I6 for a purpose to be hereinafter described. The latch I1 is formed in a generally hooked shape, being slotted as at 24 and having an ear 25. A pin or keeper 23 is fixed to wall 2'! of casing I near the top edge thereof and is adapted to be received within the slot 24 of latch I! and engages with ear 25 to secure the lower end of the cover 2 to wall 21. The upper end of the cover 2 is at the same time secured against movement and to wall 9 of the casing I by the reception of the projections 6 and I within depressions 8. Moving the actuating member 2| clockwise to effect rotation of the latch I to disengage the ear 25 from the pin 26 will permit the cover 2 to be readily detached from casing I for the cover 2 may then be rotated about the projections 6 and I and removed from the casing I. A spring 28 is coiled about the cylindrical portion |8 f latch I1 and has one end 29 thereof bent about an edge 3| of the latch I1. The oppositeend 32 of the spring 28 bears against a slidable member 33 whose use will be explained hereinafter. Spring 28 exerts its force to continually bias the latch I1 and the actuating member 2| carried thereby in a counterclockwise direction, as viewed in Figures 2 and 6, and movement of the latch |'I clockwise to disengage the ear from the pin 26 will be made against the bias of spring 28, so that release of the actuating member 2| after actuation allows the spring force to come into effect to pivot both the actuating member 2| and latch IT in a counter-clockwise direction. The actuating member 2| is provided with an edge 34 which is engageable with an edge of a flange 35 extending from the member 23 to limit the extent of counterclockwise movement of the actuating member 2| and the latch I'I when the cover 2 has been removed from the casing I, engagement of latch IT with pin 26 limits the extent of counter-clockwise movement of latch I and member 2| when the cover 2 is in position upon the casing I. A second edge 36 provided on the actuating member 2! is engageable with a surface 31 of flange 35 when the actuating member 2| is moved in a clockwise direction and thus determines the extent of movement of the actuating member 2| and the l mb I! in that direction. Ear 25 is beveled as at 38 to provide an inclined surface along which the pin 25 slides when the cover 2 is being placed upon the casing I. Thus, movement of the cover 2 relative to casing I effects a cam action, with the pin 26 rotating the latch I'I clockwise and against the bias of spring 28 until the slot 24 is provided adjacent the pin 26 whereupon the spring 28 exerts its force to pivot the latch counterclockwise and to dispose ear 25 beneath pin 26 and thus automatically detachably lock the cover 2 closed.

An interlocking means is provided for the cabinet which locks the cover closed and maintains the operating handle in its off position for the interlocking means is adapted to engage and hold the operating handle and to act upon the cover releasing means comprising the actuating member 2| and the latch IT to render it inoperative, and thus effect a situation where the cover 2 cannot be removed from the casing I without first disabling the interlocking means. The interlocking means comprises a slidable member 33 which is carried by the cover 2. An end 39 of the slidable member 33 extends through an opening 4| in the end l6 of cover Z'to the exterior thereof; the opposite end 40 is supported within the cover and lies alongside the edge 42 of opening I2in cover 2. A member 43 is welded to the interior top surface of cover 2 and has a portion 44 bent therefrom and formed to present a surface spaced from and parallel to the top of the cover, the interior end 40 of the slidable member 33 is receivable within this space and lies upon member 44 which thus afiords a support for the slidable member 33 within the cover 2. End 40 is downwardly bent as at 45 and is adapted to engage with an edge 46 on support 44 to limit the extent of movement of slidable member 33 outwardly from the cover 2. The opposite end 39 of the slidable member 33, which is disposed at the exterior of the cover 2, is bent upwardly as at 48 to provide a portion which can be easilylgrasped for effecting manual movement of the slidable member 33 inwardly and outwardly. Portion 48 is adapted to engage the outer surface of end wall IE to limit the extent of inward movement of slidable member 33. The opening 4| and the support 44 which support the ends 39 and 40 of the slidable member 33 are so located relative to each other that the movements of the slidable member 33 into and out of the cover 2 will be substantially rectilinear. To render the actuating member 2| inoperative, the slidable member 33 is pulled outwardly so that a surface 49 thereon is presented above a projecting portion 5| exending from the actuating member 2|. Surface 49 lying in the path of movement of actuating member 2| prevents its being rotated in a clockwise direction and thus prevents the rotation of the latching member H, and the ear 25 of the latch II will remain in engagement with pin 26 to thereby retain the cover closed. When the slidable member 33 is actuated inwardly to occupy its innermost position, actuating member 2| will then be freely actuable for the slidable member will no longer be in an obstructing position. Member 23 spaces the actuating member a sufficient distance from the end wall I6 of cover 2 that the actuating member 2| can clear the outer surface of portion 48 of the slidable member 33 and thus can freely rotate. A rectangular piece 52 is secured by welding to the exterior end 39 of the slidable member 33 and upon the upper surface 53 thereof, and with the slidable member 33 in it innermost position the piece 52 engages the inner surface of end wall I6 to prevent this member 33 accidentally moving out of the cover. The end 39 is formed as shown in Figure 4, to provide a portion 54 which is spaced from and parallel to the interior top surface of the cover 2. The portion 54 is adapted to pass through opening 4| in end wall It and the surface 53 thereof normally lies in engagement with the top edge 55 of this opening 4i due to the manner in which slidable member 33 is formed and assembled and due to the bias of spring 28. The opening 4| is of suflicient width to allow the ready passage of the slidable member 33 and of the rectangular piece 52 carried thereon. If the slidable member 33 were occupying its innermost position Within the cover 2 and if it were desired to pull it out therefrom, it would be necessary first to press down on the end 33 to slightly bend or flex the slidable member 33 downwardly toward the bottom of the casing I to enable the piece 52 to clear the upper edge 55 of opening 4I. After the slidable member 33 has been pulled out sumciently to allow the piece 52 to pass completely through Opening M, the slidable member 33 will move bodily upwardly toward the plane of the top surface of cover 2, under its inherent resiliency and under the force exerted by the spring 23. This movement of the slidable member 33 upwardly will move the rectangular piece 52 above the upper edge 55 of opening 4! and then the slidable member 33 cannot be pushed into the cover 2 again until end 39 is again bent downwardly sufficiently to allow the top surface of piece 52 to clear edge 55 of opening M. The piece 52 provides a desirable feature in that it lessens the possibility of accidentally moving the slidable member 33 into the cover 2 and thus prevents movement of the acuating member 2| at a time when it should be locked against movement. The slidable member 33 cannot occupy its outer position unless the operating handle I3 is in its llofifl on position and force were applied to the slidable member 33 to effect movement thereof, the downwardly extending piece 45 provided at the interior end 40 of the slidable member 33 would engage the projection I 4 formed on the handle i 3 and thus the projection l4 provides an obstruction in the path of movement of the slidable member 33, and this obstruction remains until the handle I3 is moved to off position whereby the projection I 4 move a sufiicient distance that it no longer blocks extension 45 and the slidable member 33 will freely move to its outer position. With the slidable member 33 in its outermost position, the rectangular piece 52 will be disposed above the opening 4! and adjacent the outer surface of end wall I5, as described above, so that'if it were desired to move the handle I3 back to on position it could not be accomplished because projection I4 of handle !3 will engage extension 55 and its movement will be halted thereby. Extension 45 will not be moved by the application of force on the handle I3 because of the engagement of piece 52 with end wall able member 33 in its outermost position and thereby holds the extension 45 in an obstructing position. To effect return movement of the handle I3 back to on position, the slidable member 33 must be flexed sufiiciently to carry piece 52 below edge 55 of opening 4!, whereupon it can be pushed inwardly to carry extension 45 to a noninterfering position. Thus, when the slidable member 33 has been moved into its outermost position, the actuating member 2| cannot be op position, for if the handle I3 were in its- IB which looks the sliderated to move latch I! to unlatching position and the cover, 2 will be locked closed, but before the slidable member 33 can be moved to its outermost position the operating handle I3 must occupy its off osition and when the slidable member 33 i in its outermost position the operating handle I3 cannot be moved to on position and Will be locked 01f.

It' is evident from the arrangement of parts as described above that the operating handle I3 can be moved from on position to off position without applying manual force directly to the handle. This can be accomplished through the slidable member 33. If the handle I3 were in on position and the slidable member 33 were pulled outwardly, extension 45 thereon would engage projection M on handle I3 and would thereby move the handle I3 to perform a switching operation.

Means are provided in this invention to prevent the cover 2 being removed from the casing I while the operating handle is in on position. This means comprises an L-shaped flang 56 extending from member 43 welded to the top of cover 2. Leg 5! of the flange 56 i spaced from the top of the cover 2 and lies generally parallel thereto. With the handle I3 in the on position, projection I4 on the handle I3 will lie in the space between leg 51 and the top of cover 2 and removal of the cover 2 cannot be had for the projection I4 will engage leg 57 and thereby obstruct movement of the cover 2 to open position. If the handle I3 were moved to off position, projection I 4 would then be moved from between leg 5'! and the top of cover 2 and the cover could then be removed. This is a desirable safety feature in that the circuit must be broken before the cover 2 can be removed from the casing I. Thus, the cover 2 can be held fast to the casing I even though the slidable member 33 is in its innermost position and the actuating member 21 is freely actuable.

As shown in Figures 1 and 3, the slidable member 33, is provided with an opening 58 which, when the slidable member 33 is in its outer position, is adapted to receive the shackle of a standard padlock 59, as shown in Figure 1. With the slidable member 33 in its outer position, the operating handle I3 will occupy its off position and the actuating member 2I and latch I! are held inoperative. Insertion of the padlock shackle into opening 58 will prevent actuation of the slidable member 33 into the cover 2 and thus the switch will be positively locked in its oil position because of the extension 45 engaging projection I 4 and the cover 2 will be positively locked against opening movement relative to casing I because actuating member EI cannot be moved until the padlock 59 is removed.

A flange 61 extending from the member 23 is provided with an opening 62 therethrough which is also adapted to receive the shackle of a padlook. If a padlock were inserted through opening 62, the actuating member 2I could not be actuated for the shackle of the padlock would obstruct its movement and since the actuating member 2i could not be moved, the latch I! could not be disengaged from pin 26 and the cover 2 would be locked to casing I. With this arrangement, however, the operating handle I3 is not locked off as when a padlock is received by opening 58 in slidable member 33 but rather the operating handle I3 may be freely operated between its on and off positions as long as slidable member 33 remains in its innermost position.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto, as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims:

What is claimed is:

1. In an enclosing cabinet for an electric switch, a casing, a cover for said casing, a manually movable handle for effecting operation of said electric switch and operable from the exterior of the cover, a plurality of elements provided on the interior of the cover and the casing and interengageable when the cover is moved to closed position to latch the cover closed, releasing means carried by said cover at the exterior thereof and manually operable to disengage said elements to permit opening of the cover, means fixedly supported upon an interior surface of said cover, and a portion of said manually movable handle being engageable with said fixed means when said manually movable handle is in the on position to prevent the cover being opened even though the releasing means is operated to cover disengaging position.

2. In an enclosing cabinet for an electric switch, a casing, a cover for said casing, a manually movable handle for effecting the operation of said electric switch and operable from the exterior of the cover, a plurality of elements provided on the interior of the cover and the casing and interengageable when the cover is moved to closed position to latch the cover closed, releasing means manually operable at the exterior of the cabinet to disengage said elements to permit opening of the cover, a padlock, and means provided on said cabinet whereby said padlock may be supported at a plurality of predetermined positions, said padlock when mounted at a first position being efiective to maintain the cover closed while permitting normal operation of said manually movable handle, and when supported at a secondposition being adapted to maintain the cover closed and the manual handle in off position.

3. In an enclosing cabinet for an electric switch, a casing, a cover for said casing, a manually operable handle for said switch and operable from the exterior of said cover, a plurality of separately mounted means for holding said cover on said casing, one of said means comprising a member carried by said cover cooperating with said switch handle when in the on position to hold the cover closed, and the other comprising interengageable members on the interior of the cover and casing to releasably hold the cover to the casing, and a releasing means manually operable from the exterior of th cabinet for disengaging said interengageable members to permit the cover to be opened.

4. In an enclosing cabinet for an electric switch, a casing, a cover for said casing, a manually movable handle for effecting operation of said electric switch and operable from the exterior of the cover, a plurality of elements provided on the interior of the cover and the casing and interengageable when the cover is moved to closed position to latch the cover closed, releasing means carried by said cabinet at the ex-, terior thereof and manually operable to disengage said elements to permit opening of the cover, means fixedly supported upon an interior surface of said cover, a portion of said manually movable handle being engageable with said fixed means when said manually movable handle is in the on position to prevent the cover being opened even though the releasing means is operated to cover disengaging position, and a movable member supported by said cover and adapted when said manually movable handle is in off position to prevent movement of said releasing means to thereby retain the cover closed.

5. In an enclosing cabinet for an electric switch, a casing, a cover for said casing, a manually movable handle for effecting operation of said electric switch and operable from the exterior of the cover, a plurality of elements provided on the interior of the cover and the casing and interengageable when the cover is moved to closed position to latch the cover closed, releasing means mounted at the exterior of the cabinet and manually operable to disengage said elements to permit opening of the cover, means fixedly supported upon an interior surface of said cover, a portion of said manually movable handle being engageable with said fixed means when said manually movable handle is in the on position to prevent the cover being opened even though the releasing means is Operable to cover disengaging position, and a slidable member supported by said cover and positionable to engage said releasing means whereby said releasing means is inoperative to disengage said latching elements, said slidable member at the same time adapted to engage with said manually movable handle to retain it in the off position.

6. In an enclosing cabinet for an electric switch, a casing, a cover for said casing, a manually movable operating member for said electric switch and operable from the exterior of the cover, a plurality of elements on the interior of the cover and casing interengageable when the cover is moved to closed position to latch the cover in closed position, releasing means supported on the cabinet and manually operable to unlatch said elements to permit opening of the cover, and a member movably mounted on said cover and operative to a position to block the operation of the releasing means to prevent disengagement of said latching elements, a portion of said manually movable operating member being engageable with said movably mounted member, and means provided on said movably mounted member and cooperating with a wall of said casing to maintain the manually movable operating member in the position it occupies when said movably mounted member blocks thev operation of said releasing means.

'7. In an enclosing cabinet for an electric switch, a casing, a cover for said casing, a manually movable handle for effecting operation of said electric switch and operable from the exterior of the cover, a plurality of elements provided on the interior of the cover and the casing and interengageable when the cover is moved to closed position to latch the cover closed, releasing means carried by said cabinet at the exterior thereof and manually operable to disengage said elements to permit opening of the cover, means fixedly mounted on said cover and engageable with said manually movable handle when in "on position to prevent the cover being opened even though the releasing means is operated to cover disengaging position, and a member movably mounted on said cover and positionable when said manually movable handle is in ofi position to obstruct the operation of the releasing means to prevent disengagement of said latching elements, and means provided on said movably mounted member adapted to become effective when said movably mounted member is moved to obstructing position to retain said manually movable handle in ofi position,

8. In an enclosing cabinet for an electric switch, a casing, a cover for said casing, a manually movable handle for the switch and operable from the exterior of the cover, a latch carried by said cover and on the interior thereof, a fixed member on said casing automaticall engageable with said latch when the cover is moved into closed position to hold it on the casing, a releasing member mounted at the exterior of the cover and actuable to effect disengagement of said latch from said fixed member to permit opening of the cover, a member fixedly mounted to said cover and adjacent said switch handle, said member having a portion thereof spaced from the top of the cover and disposed substantially parallel thereto, a projection on said switch handle which is receivable within said space when said switch handle is in on position to prevent the cover being moved open even though the releasing means is operable to cover disengaging position, a slidable member supported within the cabinet and movable, after said manually movable handle is in off position, to a position wherein it blocks the releasing means to prevent it effecting disengagement of said latch from said fixed member, and means provided by said slidable member adapted to become effective when said slidable member is moved to blocking position to retain said manually movable handle in off position.

9. In an enclosing cabinet for an electric switch, a casing, a cover for said casing, a manually movable handle for the switch and operable from the exterior of the cover, a latch carried by said cover and on the interior thereof, a fixed member on said casing automatically engageable with said latch when the cover is moved into closed position to hold it on the casing, a releasing member mounted at the exterior of the cabinet and actuable to effect disengagement of said latch from said fixed member to permit opening of the cover, a slidable member supported within the cabinet and positionable, after said handle has been moved to off position, to obstruct the movement of said releasable means to prevent it from efiecting disengagement of said latch from said fixed member, and means carried on said slidable member operative when said slidable member occupies its obstructing position to lock said slidable member against movement, said slidable member at the same time being engageable with said manually movable handle and thereby being effective to prevent said manually movable handle being moved out of off position.

10. In an enclosing cabinet for an electric switch, a casing, a cover for said casing, a manually movable handle for the switch and operable from the exterior of the cover, a latch carried by said cover and on the interior thereof, a fixed member on said casing automatically engageable with said latch when the cover is moved intclosed position to hold it on the casing, a releasing member mounted at the exterior of the cover and actuable to effect disengagement of said latch from said fixed member to permit opening of the cover, a member fixedly mounted to said cover and adjacent said switch handle, said member having a portion thereof spaced from the top of the cover and disposed substantially parallel thereto, a projection on said switch handle which is receivable within said space when said switch handle is in on position to prevent the cover being moved open even though the releasing means is operated to cover disengaged position, a slidable member supported by said cover and positionable, after said handle has been moved to off position, to block the movement of said releasable means to prevent it from effecting disengagement of said latch from said fixed member, and a member carried by said slidable member and being disposed exteriorly of said casing when said slidable member is in said blockin pOsition, and being engageable with a wall of said casing to lock said slidable member against movement, said slidable member at the same tim having engagement with said manually movable handle and thereby being effective to prevent said manually movable handle being moved out of off position.

11: In an enclosing cabinet for an electric switch, a casing, a cover for said casing, a manually movable handle for effecting operation of said electric switch and operable from the exterior of the cover, a plurality of elements provided on the interior of the cover and the casing and interengageable when the cover is moved to closed position to latch the cover closed, releasing means provided on the cabinet and manually operable to disengage said elements to permit opening of the cover, and movable means separate from said manually movable handle and carried by said cabinet and operative on said manually movable handle to effect movement thereof from one position of rest to a second position of rest.

12. In an enclosing cabinet for an electric switch, a casing, a cover for said casing, a manually movable handle for effecting operation of said electric switch and operable from the exterior of the cover, an interlock for said cover comprising a plurality of elements provided on the interior of the cover and the casing and interengageable when the cover is moved to closed position to latch the cover closed, releasing means for said cover interlock and manually operable to disengage said elements to permit opening of the cover, and movable means carried by said cabinet and being positionable to block the movement of said releasing means to prevent movement thereof to effect disengagement of said elements, said movable means having an operative engagement with said manually movable handle to effect movement thereof from one position of rest to a second position of rest.

13. In an enclosing cabinet for an electric switch, a casing, a cover for said casing, a manually movable handle for effecting operation of said electric switch and operable from the exterior of the cover, an interlock for said cover comprising a plurality of elements provided on the interior of the cover and the casing and interengageable when the cover is moved to closed position to latch the cover closed, releasing means for said cover interlock and normally operable to disengage said elements to permit opening of the cover, and a slidable member supported by said cabinet, and being actuable to a position wherein it blocks the movement of said releasing means to prevent movement thereof to effect disengagement of said elements, said slidable member being engageable with said manually movable handle to effect movement thereof to off position when it is actuated to blocking position.

CARL A. SCHAEFER.

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