US2304627A - Switching apparatus - Google Patents

Description

E. K. CLARK SWITCHING APPARATUS Dec. 8, 1942.

Filed Dec. 15, 1940 2 Sheets-Sheet l FIG- Dec. 8, 1942. E. K. CLARK 2,304,627

SWITCHING APPARATUS Filed Dec. 13, 1940 2 Sheets-Sheet 2 i .E "mm, mfm" I7 II INVENTOR EARL A. 624m ATTORNE Patented Dec. 8, 1942 SWITCHING APPARATUS Earl K. Clark, Mansfield, Ohio, asllgnor to Westinghouse Electric 3; Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application December 13, 1940, Serial No. 370,049

14 Claims. (Cl. 200-38) My invention relates to switching apparatus,

more particularly to time-controlled switching apparatus, and has for an object to provide improved apparatus of this kind.

A further object of the invention is to provide a novel double-throw, time-controlled switching apparatus, movable through an open position wherein preliminary sequential operation of the switching members is eflected, as the apparatus is moved from one closed position to a second closed position.

A further object of the invention is to provide manually-operated switching apparatus of the kind set forth wherein the apparatus may be actuated manually in one direction from one closed position through an open position to a second closed position and, when actuated manually in a reverse direction, movement of the apparatus to its open position only is eilected.

A further object of my invention is to provide a time-controlled, double-throw switching apparatus manually movable from a first closed position to a second closed position and movable from the second to the first closed positions only with the assistance of the timing mechanism.

A still further object of the invention is to prevent short circuits in a double-throw, timecontrolied switching mechanism.

It is a still further object of the invention to provide an improved time-controlled switching apparatus having a plurality of switching members operated sequentially as the apparatus is moved from one position to a second position, wherein, manually-operated means is provided for completing the sequential operations of the switching members when the manually-operated means is adjusted in one direction and wherein a portion of the sequential operations of the switching members is effected by the time-conin Figs. 1 to-3 taken substantially on the line IV--IV of Fig. 2;

Fig. 5 is a central transverse sectional view of the switch taken substantially along the line V-V of Fig. 2; I

Fig. 6 is a rear view of the switch handle structure as viewed from the plane VIVI in Fig. 5; and,

Figs. 7 to 11, inclusive, are diagrammatic views showing relative positions of various elements of the handle for different operating positions thereof.

This invention is herein disclosed particularly with respect to a switching means comprising a plurality of switches actuated in predetermined relation by a single switch actuating cam member, together with a timing mechanism which is manually adjustable to select any desired time interval during which the switches are adjusted to one position. At the end of the time interval selected, the timing mechanism actuates the switches to another controlling position. The specific switch disclosed herein is particularly adapted for use in controlling heater circuits of thetype employed in an electric range or the like. Such circuits are shown, for example, in the copending applications of C, H. Hodgkins, Serial No. 369,819, filed December 12, 1940 and E. K. Clark, Serial No. 368,495, filed December 4, 1940, both of which are assigned to the assignee of the present application.

Although this particular switching means is especially designed for use in the heating circuit disclosed in the above-mentioned copending app itrolled means upon adjustment of the manuallyoperated means in a reverse direction.

These and other objects of this invention will be apparent from the following description and claims taken in connection with the accompanying drawings forming a part of this application, in which:

Fig. 1 is a front view of a preferred embodiment of a time-controlled switch constructed in accordance with this invention;

Fig. 2 is a front view of the switch shown in Fig. 1 with the operating handle and switch casing cover removed;

Fig. 3 is a bottom view of the switch shown in Figs. 1 and 2;

Fig, 4 is a sectional view of the switch shown The switch disclosed is not only adapted to have two controlling positions by virtue of the fact that certain of the switches incorporated therein are of the double-throw type, but the switch has the further feature of providing a sequential operation of certain of the switches when the control means is initially moved to select a predetermined time interval for maintaining the switches in one active position, and this sequential operation obviously will also take place at the end of the time interval in a reverse sequence. The reason for providing sequential operation of certain of the switches preferably, is to obtain a time interval between the operation of the switches. Where the switches may also be manually operated, this purpose may be defeated ii the operator quickly moves the switch control means so that the sequentially-operated switches are actually operated substantially simultaneously. In order to provide against such an occurrence, the switch disclosed is arranged so that sequential operation of the contacts can take place at least upon movement of the switch control in one direction, only under the influence of the timing mechanism, to thereby preserve the time delay between succeeding switch operations.

The switch illustrated is preferably supported in an insulating casing ID of any desired insulating material, preferably a molded insulating material, with the casing I6 having a bottom wall side walls l2, l3, l4 and I5, and an open front face. Suitably secured on the bottom wall of the casing at one end thereof are terminals i6, i1 and I8. Mounted within casing III in adjacent corners thereof, respectively, are switch blade supports l9 and 2|, conductively connected to terminals i6 and |6, respectively, for supporting switch blades 22 and 23. These switch blades are preferably 01' a resilient conducting material so as to be normally biased into engagement with fixed contacts 24 and 25, respectively, mounted on bottom wall II in opposite corners of casing l6. Switch blades 22 and 23 may be moved into engagement with fixed contacts 26 and 21, respectively, also mounted on bottom wall I l. Contacts 21, 25, 26 and 24 are mounted on supports extending through the bottom wall ll of casing in, to provide terminals 23, 29, 3| and 32, respectively, at the outer side thereof. Contacts 26, 24 and 21, 25 are located in restricted arcing chambers, formed by baille members 33 in the casing integral with side wall l3 and bottom wall II, and by an insulating cover plate 34 overlying the baffles and contacts, to form are chambers of insulating material having an opening merely to accommodate movement of the switch blades 22 and 23. Terminal I1 is conductively associated with a contact 35 shown in Fig. 4 and cooperating with a switch blade 36 mounted in the casing on the bottom wall thereof. Switch blade 36 (Fig. 4) is conductively associated, through bottom wall H of casing H), with a terminal strap 31. It will be noted that the contact 35 is also positioned in a restricted arc chamber formed by a recess 38 in casing l6.

Switch blades 22, 23 and 36 are actuated by a single cam member 39 in the form of a block of insulating material having a substantially central opening therethrough, so as to be rotatably mounted on a shaft 4| secured in the bottom wall of casing l6. Cam member 39 is circular in form, and is provided on its periphery with upper and lower cam surfaces 42, 43 for actuating switch blades 22 and 23, respectively. By reference to Figs. 2 and 5, it will be noted that switch blades 22 and 23 are provided with relatively offset cam rollers 44 and 45, respectively, for cooperation with peripheral cam surfaces 43 and 42, respectively, on cam member 39. Cam member 39 is also provided with a recess 46 in its undersurface for cooperation with a struck-up portion 41 on switch blade 36, to actuate switch blade 36 in a predetermined sequence with respect to switch blades 22 and 23. Cam member 39 is provided in its upper surface with a pair of spaced sockets 46 adapted to receive a correspondingly spaced pair of driving prongs 49 fixed to the shaft of a timing mechanism, generally indicated at 52. driving prongs 49 project through an opening in insulating plate 34 and are received in sockets 46 in the cam member for driving engagement therewith.

It will be noted that operating cam 36 is provided with opposed substantially identical raised and depressed cam portions connected by intermediate cam portions 63 and 64(see Fig. 2). It will be obvious that when cam block 36 is rotated in a clockwise direction, as viewed in Fig. 2, the cam rollers 44 and 46 on switch blades 22 and 23, respectively, will engage the intermediate cam portions 63 and 64 to be moved thereby to a position intermediate their associated contacts 26, 24 and 26, 21. It will also be noted that Just prior to engagement of cam portions 63 and 64 with the switch blade rollers that the struck-up por tion 41 on switch blade 36 will enter slot 46 in the lower face of cam block 39 to thereby permit switch blade 36, which is normally biased upwardly, to separate from its cooperating contact 35. Separation of switch blades 22 and 23 from their contacts 24 and 26, respectively, then occurs, after which the blade rollers 44 and 46 ride onto the outer raised portions of the cam block and move the switch blades into engagement with the outer contacts 26 and 21, respectively. Rotation of cam block 36 in a counterclockwise direction will provide a reverse sequence of operation; that is, switch blades 22 and 23 will first be moved out of engagement with contacts 26 and 21, respectively, to a. position intermediate their associated contacts and out of engagement therewith, after which the switch blades are permitted to close to inner contacts 24 and 26, and finally the end of slot 46 in cam block 39 is reached and blade 36 is forced into engagement with contact 35.

The timing mechanism 52 is provided with a coil spring 55, one end of which is connected to drive shaft 5|, and the other end of which is connected to the timer frame as at 56. Drive shaft 6| has a gear 51 (Fig. 5) rotatably mounted thereon and frictionally secured for movement with the shaft by a resilient cup-shaped washer 56 keyed to the shaft and frictionally engaging gear 51. Gear 51 meshes with a pinion gear 66, the latter operating an escapement mechanism (not shown) in a well-known manner. The switching structure, including the timing mechanism, described heretofore, is the invention of C. H. Hodgkins and is disclosed and claimed in his copending application Serial No. 369,820, filed December 12, 1940.

The open-ended switch casing I6 is closed by a plate 6| which is secured to the switch casing by screws 62. The shaft 5| extends through a suitable opening formed in the plate 6| and carries a handle mechanism, generally indicated by the numeral 63, at its outer end. The handle mechanism 63 includes a rotatable knob 64, preferably of insulating material and having an insert or collar 65 secured therein. An outwardlyextending arm 66 is secured to the lower end of the collar 65 and moves with the collar 65 at all times. The knob 64 and its insert 65 are loosely carried by the shaft 5| so that angular movement of the knob 64 and insert 66 relative the shaft 5| is afforded during some periods of operation, as described hereinafter. Axial movement of the knob 54 relative the shaft 6| is prevented by a set screw 61 which extends within an annular slot 66 formed at the end of the shaft 5|.

An index carrier 69, having an index 13 (Figs. 1 and 7) formed thereon, frictionally engages, at its inner end, the collar 65 and, when unrestrained, moves angularly with the knob 64 and collar 66. The outer end of the carrier 66 is disposed between stops II and 12 fixed to the I cover plate 6|, which stops H and I2 limit angular movement of the index carrier 69. The index l3 cooperates with graduated indicia 14 formed on the front surface of the knob 64. As shown in Figs. 7 to 11, inclusive, the indicia 14 represents number of minutes.

A driving connection'between the handle 64 and the shaft 5| is provided by an arm 15 which is fixed to the shaft 5| and which carries a pin 16 adjacent its outer end. The pin 16 extends within an elongated opening 11 formed in the arm 66. A tension spring 16 provides a bias between the arms 66 and I5 and tends to move the arm 66, handle 64, and index carrier 69 counterclockwise with respect to the arm 15 as viewed in Figs. 7 to 11, inclusive. counterclockwise movement of the knob 64 beyond the position shown in Fig. 7 is prevented by a projection 19 formed on the undersurface of the knob 64, which proiection engages the index carrier 69 in the position of the apparatus shown in Fig. 7.

The, switch apparatus described heretofore is adjustable to first and second active or circuitclosing positions between which there is an inactive or off position. The apparatus as shown in Figs. 1 to '7, inclusive, is disposed in its first active position wherein the switch blades 22 and 23 engage their respective stationary contacts 24 and 25 and wherein the switch blade 36 engages its contact 35. The positions of the arms 15 and 66 and the handle 64 in this first active position of the apparatus is shown in Fig. 7'. In-this first active position, a three-wire circuit is established wherein the terminal I6 is electrically connected to the terminal 3|, the terminal I8 is electrically connected to the terminal 29, and the terminal I1 is electrically connected to the terminal 31. Adjustment of the switching apparatus through its inactive position to the second active or closed position will now be described.

The period of time that the apparatus is to be retained in its second active position is variable up t thirty minutes in the particular embodiment which I have disclosed, at the end of which time it is first moved to its inactive or off" position and thence to the first active position as shown in the drawings. Adjustment of the apparatus for fifteen minutes operation in its second active position may be effected by moving the knob 64 angularly, clockwise from the posi- .tion shown in Fig. 7 totthe positions shown in Fig. 9. This angular clockwise movement of the knob or handle 64 effects clockwise movement of the arm 66. As the pin 16 engages the arm 66, clockwise movementsof the arm 15 and shaft are also efiected. Movement of the shaft 5|, of course, winds the spring 55 of the clock mechanism. During the initial clockwise movement of the knob' 64, the index carrier 69 moves with the knob because of its frictional engagement therewith until the carrier 69 engages the stationary stop 12 as shown in Fig. 8. In the example illustrated, this movement of the knob 64 (from Fig. 7 to Fig. 8) represents three minutes of reverse rotation of the shaft 5|, as determined by the clock mechanism 52 although the index 13 is still opposite the zero indexon the knob 64. The additional movement of the knob 64 and arms 66 and. 15 (from Fig. 7 to Fig. 8) moves the fifteen-minute graduation on the knob 64 opposite the index 13 and winds the clock spring for fifteen minutes reverse movement of the shaft 5|. During the total movement of the knob 64 (from Fig. 7 to Fig. 9), the timing mechanism 52 is wound for a total of eighteen minutes operation, it being understood that the driving arm 16 is moved by the pin 16 as the knob 64 and its arm 66 are rotated from the position shown in Fig. 7 to the position shown in Fig. 9; p

when the operator releases the knob 64 after moving the same to the position shown in Fig. 9, the tension spring 16 effects counterclockwise rotation of the knob 64 and the index carrier 69 relative. the driving arm 15, to the position shown in Fig. 10. During this counterclockwise rotation of the knob 64, the driving arm I5 remains substantially stationary as the lost motion defined by the pin 16 and slot I1 is taken up.

During the transition of the apparatus from the position shown in Fig. 7 to the position shown in Fig. 8, the cam 39 and the arm 15, which moves with the cam 39 at all times, are moved clockwise. During the initial. movement of the cam, the struck-up portion 21 of the switch arm 36 enters thearcuate recess 46 and, therefore,

the switch arm 36 is disengaged from the contact 35. Further movement of the cam 39 clockwise disengages the switch arms 22 and 23 from their respective contacts 24 and 25 as the rollers 44 and 45 ride upwardly on the intermediate cam portions 53 and 54. In this open position, all of the switch arms 22, 23 and 36 are completely disengaged from any stationary contacts and it is in this open position of the switch that the arms I5 and 66 and the handle 64 assume the positions shown in Fig. 8. I

Further clockwise movement of the cam 39 is effected as the handle 65 and arm 15 are moved from the position shown in Fig. 8 to the position shown in Fig. 9. During the initial part of this movement, the rollers 44 and 45 ride up on the outer cam surfaces 42 and 43 and, therefore, move the switch arms 22 and 23 into engagement with their stationary contacts 26 and 21, respectively. The switch is now in its second active position wherein a two-wire circuit is established, the terminals l6 and I6 being electrically connected to the terminals 32 and 28, respectively. It will be understood that no movement of the cam 39 is effected during the described counterclockwise movement of the arm 66 and knob 64 from the position shown in Fig. 9 to that shown in Fig. 10. Slow counterclockwise rotation of the driving arm 15, the arm 66 and the knob 64 towards the zero position of the latter is then effected by the clock mechanism. The cam 39 is also moved counterclockwise at this time. In Fig. 11, I have shown the relative positions of the driving arm 15, the arm 66 and the knob 64 in the zero position.

When the driving arm 15 and the knob 64 reach the zero position (Fig. 11), the rollers 44 and 45 ride down on the intermediate cam surfaces 53 and 54 and, therefore, move the switch arms 22 and 23 to their intermediate inactive or open positions. Movement of the driving arm 15 continues for an additional three minutes in the example described, or until the pin I6 engages the left-hand end of the slot 11 formed in the. lever 66. At this time, however, it will be noted that the knob 64 and its arm 66 remain stationary, the index carrier 69 being in engagement with the stop II and the projection 19 on the knob 64 engaging the index carrier 69. It is during this three-minute additional operation that the tension spring 18 is extended to the position shown in Fig. 7. It is also during this three-minute operation that the rollers 44 and 46 become disengaged from the cam 39, whereby movement of the switch levers 22 and 23 into engagement with the contacts 24 and 25 is effected. Toward the end of the additional threeminute movement referred to, the struck-up portion 41 of the switch lever 36 rides out of the arcuate slot 46 and depresses the switch lever 38 into its circuit-closed position. The apparatus,

the switch blades 36, 22 and 23 are disengaged from any stationary contact. The position of the knob 64 and the arms 66 and 15 corresponding to this position of the switch is shown in Fig, 11. Movement of the apparatus to its first active position shown in the drawings from the off position is effected by the timing mechanism as described heretofore. This operation is incorporated into the device to prevent short circuits which might occur if the apparatus were manually actuated rapidly from the second active position to the first active position, as the movement of the switch arms 22, 23 and 36 would be substantially instantaneous if quickly operated. In other words, the switch arm 36 and the stationary contact 35 may be engaged before the breaking of the switch arms 22 and 23 from their contacts 25 and 2! or at least before any BIC which might be drawn between these contacts were extinguished.

In the operation described, it will be understood that slippage occurs between the gear 51 and the resilient cup-shaped washer 58 during any manual movement of the shaft 5| either in a spring-winding direction or an unwinding direction and that the gear 51 is driven by the shaft 5| through the cup-shaped washer 58 during operation of the shaft 5| by the timing mechanism 52. An additional contact 8| is shown which is engageable with the switching arm 22 in the second active position of the switch. The contact 8i may be connected to a suitable indicating device, such as a lamp, which when energized would indicat that the switch is in its second active position.

From the foregoing description, it will be apparent that I have provided an improved timecontrolled switching apparatus having a plurality of switch arms moved sequentially during the transition of the apparatus from one active position to a second active position and wherein short circuiting of the apparatus is precluded during the period of transition. As the possibility of a short circuit is greater when the switching apparatus is manually actuated in one direction, I provide novel means for preventing rapid manual movement of the apparatus in this direction. Operation of the switching apparatus under control of the timing mechanism completes the sequential switching operations, at least in part. when manual operation in this direction is to be effected. It will be understood that the specific form and number of switching blades are shown by way of example and that other arrangements of the blades and the number which are employed may be varied.

While I have shown my invention in but one form, it will be obvious to those skilled in the 76 art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. In switching apparatus, the combination of a switching mechanism having a plurality of poles sequentially operated for effecting a plurality of preliminary switching operations during movement of the switching mechanism between first and second positions, manually-operated means for moving 'said switching mechanism from its first position through said preliminary switching operations to its second position, a lost motion device associated with said manually-operated means for preventing manual movement of the switching mechanism from its second position through its preliminary switching operations to its first position, a timing mechanism for moving the switching mechanism from its second position through said preliminary switching operations to its first position, and means for varying the period of time that the switching mechanism is retained in said second position.

2. In switching apparatus, the combination of timing mechanism having a member movable in two directions, said member being driven by the timing mechanism in one direction for a period of time predetermined by the amount of movement manually imparted to said member in an opposite direction, switch means including a plurality of sequentially operated switching devices actuated by said member to perform a plurality of successive switching operations as said member approaches an end of its movement, a handle for moving said member, and means associated with said handle for actuating said member in said opposite direction any selected amount but operative to move the member in said one direction only a lesser amount and to the position at which said successive switching operations are initiated, said successive switchng operations being then effected at a relatively low rate of speed by said timing mechanism.

3. In switching apparatus, the combination of a double throw switch movable to first and second active positions, said switch being movable to an inactive position intermediate its active positions, a handle manually movable at will for actuating the switch from its first active position through the inactive position to its second active position, a lost motion device associated with the handle and providing for manual movement of the switch from its second active position to its inactive position, a timing mechanism actuated by said handle for moving the switch from its second active position to its inactive position and thence to its first active position at relatively low speed, and means for adjusting the timing mechanism so that the period of time that the switch is retained in its second position is variable.

4. In switching apparatus, the combination of a double throw switch movable to first and second active positions, said switch being movable to an inactive position intermediate its active positions, a timing mechanism having a member movable in one direction for initiating operation of the mechanism, said timing mechanism effecting movement of said member in a reverse direction at relatively low speed, a handle manually movable at will for moving said member in said one direction and in variable amounts for varying the period of time that the timing mechanism eflects verse direction.

5. In switching apparatus, the combination of a switching mechanism having a plurality of switching elements movable to first and second active positions, said mechanism eflecting a plurality of preliminary switching operations during the period of transition between its first and second positions, 'a handle for moving the switching elements from their first active position through said transition period to their second active positions, a timer for moving the switching elements from their second active positions through the period 'of transition to their first active positions, means for varying the period of time that the switching elements are retained in their second active positions, and means for preventing movement of the switching means manually through said period of transition to their first active positions.

' 6. In switching apparatus, a timing mechanism including a member manually movable in one direction to a plurality of positions for varying the period of operation of the timing mechanism, said member being driven by said mechanism in a reverse direction, a switch movable from a first active position, through an intermediate inactive stage to a second active position as said member is manually moved in said one direction, said switch being moved from its second active position through its inactive stage to its first position as said member is driven in the reverse direction, and means associated with said manually operated member for preventing manual operation thereof in said reverse direction beyond said intermediate stage.

7. The combination of a double throw switch having first and second closed positions and an intermediate open position, manually operated means for moving the switch from its first closed position through its intermediate position to its second closed position, said means being effective to move the switch from its second closed position to its intermediate position only, a timing mechanism effective to move the switch from its second closed position through its intermediate position to the first closed position thereof, and means including said manually operated means for varying the period of time that the timing mechanism retains the switch in its second closed position.

8. In switching apparatus, the combination of a switch movable between first and second positions, a handle manually movable at will in one direction for actuating the switch from its first to its second position, means associated with the handle for preventing manual actuation of the switch from its second to its first position as movement is imparted to the handle manually in a reverse direction, a timing mechanism for actuating the switch from its second to its first position, means actuated by said handle for initiating operation of the timing mechanism as the handle is moved in said one direction, said last-mentioned means varying the duration of the period of operation of the timing mechanism dependent upon the amount of movement manually imparted to the handle in said one direction.

9. In a switching mechanism, the combination of a switch movable between first and second positions, a timing mechanism for moving the switch in one, direction, means for manually moving the switch in the opposite direction and for conditioning the timing mechanism for operation, said means including a handle having a plurality of graduations thereon, a carrier having. an index thereon cooperating with said graduatlons, means connecting said handle and carrier and providing for movement of the latter as the former is actuated and means for limiting the movement of the carrier to a predetermined amount irrespective of the amount or movement imparted to the handle.

10. In a switching mechanism, the combination of a switch movable between first and second positions, a timing mechanism for moving the switch in one direction, manually operated means moving the switch in the opposite direction and for conditioning the timing mechanism for various periods of operation depending upon the amount of movement imparted to the manually operated means, said manually operated means including a handle having indicia there.- on, a carrier including an index cooperating with said indicia, means defining a frictional connection between the handle and said carrier whereby the carrier moves with the handle as the latter is actuated and stop means for limiting movement of the carrier to a predetermined amount.

11. In a switching mechanism, the combination of a switch movable between first and sec ond positions, a timing mechanism for moving the switch in one direction, means including a ,handle member for manually moving the switch in the opposite direction and for conditioning the timing mechanism for operation, a carrier member, means connecting said handle and carrier members and providing for movement of the latter as the former is actuated, means for limiting movement of the carrier member to a predetermined amount irrespective of the amount of movement imparted to the handle member, and cooperating graduation and index means on said members.

12. In switching apparatus, a timing mechanism including a member manually movable in one direction to a plurality of positions for varying the period of operation of the timing mechanism, said member being driven by said mechanism in a reverse direction, a switch movable from a first active position, through an intermediate inactive stage to a second active position as said member is manually moved in said one direction, said switch being moved from its second active position through its inactive stage to its first position as said member is driven in the reverse direction, means associated with said manually-operated member for preventing manual operation thereof in said reverse direction beyond said intermediate stage, a carrier member, means connecting said manually-operable member and carrier member and providing for movement of the latter as the former is actuated, and means 'for limiting movement of said carrier member to a predetermined amount corresponding to the amount said manually-operated member is movable in said reverse direction solely by said timing mechanism.

13. In switching apparatus, timing mechanism having a member driven thereby in one direction for a time predetermined by the amount said member is moved in an opposite direction, switch means actuated by said member to perform a plurality of successive switching operations as said member approaches the end of its predetermined movement, ahandle mounted on said member for manual manipulation thereof, a lostmotion connection between said handle and member, resilient means for biasing said handle in said one direction with respect to said member, and stop means for said handle positioned to stop movement of said handle when moved in said one direction, whereby said member may be moved a further distance in said one direction by said mechanism, while stressing said resilient means, to complete said switching operations.

14. In switching apparatus, timing mechanism having a member driven thereby in one direction for a time predetermined by the amount said member is moved in an opposite direction, switch 20 means actuated by said member to perform a plurality of successive switching operations as said member approaches the end of its predetermined movement, a handle mounted on said member for manual manipulation thereof, a lostmotion connection between said handle and member, resilient means for biasing said handle in said one direction with respect to said member. stop means for said handle positioned to stop movement or said handle when moved in said one direction, whereby said member may operations.

EARL K. CLARK.

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