Abstract:
Four different versions of multi-position selector switches can be assembled from a kit of parts by selecting various combinations of the parts and assembling them into a housing consisting of an insulating case and cover. Inventory of parts is reduced by mutual use of some parts in two or more versions. The possible selector switch versions are a three position selector switch having three momentary pushbuttons for selectively closing two normally open contacts and opening a normally closed contact a two-position slector switch having two momentary pushbuttons for selectably closing a normally open contact or opening a normally closed contact, a three-position selector switch having three maintainable pushbuttons for selectively closing two normally open contacts and opening the same, and a three-position selector switch having three pushbuttons including a momentary pushbutton and two maintainable pushbuttons for selectively closing two normally open contacts and for opening the maintained contact. The third and fourth versions described above which have maintainable pushbuttons comprise one or two sliding interlock members having cam surfaces cooperating with respective pushbuttons for preventing depression of more than one pushbutton at a time, and a holding plate for releasably retaining the pushbuttons depressed until the latter are returned to an extended position by one of the sliding interlock members.

Description:
BACKGROUND OF THE INVENTION 
     Multi-positioned selector switches have been known heretofore. For example, E. M. Butterworth U.S. Pat. No. 4,544,810, dated Oct. 1, 1985, shows an interlocking pushbutton selector switch having two alternately operable &#34;ON&#34; pushbuttons with interlocking means to allow operation of only one of these pushbuttons at a time, latch means for maintaining either of these pushbuttons in its depressed position and a central &#34;OFF&#34; pushbutton for restoring the depressed &#34;ON&#34; pushbutton to its normal position. The &#34;ON&#34; pushbuttons have helical compression springs for returning them to their normal positions. A single movable contact spring has left and right end portions for contacting double-throw or single-throw stationary contacts. The holding latch mechanism and &#34;OFF&#34; pushbutton may be removed to provide space for a transformer and pilot light, at the same time converting the &#34;ON&#34; pushbuttons to momentary type. While interlocking pushbutton selector switches of this type have been useful for their intended purposes, this invention relates to improvements thereover. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide an improved multi-position selector switch assembly means. 
     A more specific object of invention is to provide a kit of parts that can be assembled in various combinations within a housing to provide any one of a plurality of different versions of multi-postion selector switches with some of the functional parts being mutually used in the different versions, thereby to reduce the inventory of parts that are required. 
     Another specific object of the invention is to provide the aforementioned kit of parts such as to enable assembly thereof into a multi-position momentary selector switch having two normally open contacts and one normally closed contact and being able to selectively connect a common contact to any one of three different pairs of stationary contacts for FORWARD, STOP and REVERSE motor control. 
     Another specific object of the invention is to provide the aforementioned kit of parts such as to enable assembly thereof into a two-position start-stop momentary selector switch having a normally closed contact and a normally open contact. 
     Another specific object of the invention is to provide the aforementioned kit of parts such as to enable assembly thereof into a three-position maintained selector switch of the single-pole double-throw type. 
     Another specific object of the invention is to provide the aforementioned kit of parts such as to enable assembly thereof into a multi-position switch having momentary, off and maintained positions. 
     Other objects and advantages of the invention will hereinafter appear. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1-7, 19 and 20 show a first version of a multi-position selector switch, that is, a three-position selector switch capable of connecting any combination of two out of three stationary contacts to a common contact for FORWARD, STOP and REVERSE motor operation. 
     FIG. 1 is an elevational view with the cover of FIGS. 19 and 20 removed showing the momentary pushbuttons and contacts of this first version of selector switch. 
     FIG. 2 is a fragmentary cross-sectional view of the housing of the switch of FIG. 1 taken substantially along line 2--2 thereof showing the means for connecting the cover to the switch case. 
     FIG. 3 is a side view of the center pushbutton, the front view of which is shown in FIG. 1. 
     FIG. 4 is a left side view of the left end pushbutton, the front view of which is shown FIG. 1. 
     FIG. 5 is the top view of the movable contact which is shown in front view in FIG. 1. 
     FIG. 6 is a top view of one of the normally open stationary contacts of FIG. 1. 
     FIG. 7 is a front view of the two electrically connected normally closed contacts of FIG. 1. 
     FIGS. 8-10, together with the cover shown in FIGS. 19 and 20, show a second version of the selector switch, that is, a two-position START-STOP momentary selector switch of the motor control type or the like. 
     FIG. 8 is an elevational view of this second version of switch with the cover shown in FIGS. 19 and 20 removed, showing the two pushbuttons and the contacts arrangement therein. 
     FIG. 9 is a fragmentary cross-sectional view of the switch of FIG. 8 taken substantially along line 9--9 thereof to show the manner of securing the cover to the switch case. 
     FIG. 10 is a left-side view of the plug placed in the unused pushbutton space. 
     FIGS. 11-16 show a third version of the selector switch, that is, a three-position maintained selector switch that may be used for motor reversing, HAND, OFF, AUTO operation or the like. 
     FIG. 11 is a front elevational view with the cover removed of the three-position maintained selector switch showing an assembled view of the three pushbuttons, the two slider cams, the holding member, the two operating levers and the movable and stationary contacts, with the switch being shown in its off position. 
     FIG. 12 is a fragmentary cross-sectional view taken substantially along the line 12--12 of FIG. 11 to show the relationship of the slider cams and holding member as well as the means for securing the cover to the switch. 
     FIG. 13 is a side view of one of the three maintainable pushbuttons of the switch of FIG. 11. 
     FIG. 14 is a front view of one of the slider cams used in the switch of FIG. 11 also showing in broken lines how this slider cam may be modified for use in the selector switch of FIG. 17. 
     FIG. 15 is a front view of the holding member used in the switch of FIG. 11. 
     FIG. 16 is a top view of one of the two movable contact operating levers used in the switch of FIG. 11. 
     FIGS. 17 and 18, together with the cover shown in FIGS. 19 and 20, show a fourth version of the multi-position selector switch, that is, a MOMENTARY-OFF-AUTO maintained selector switch which may be used for specialiized electrical system control such as TEST, OFF, AUTO or the like. 
     FIG. 19 is an internal elevational view of the cover for the switch case used in all four versions of the multi-position selector switch. 
     FIG. 20 is a top view of the cover of FIG. 19. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, there is shown an assembled front elevational view, with the cover removed, of the first version of three-position momentary selector switch. As shown therein, this switch is provided with a common terminal or wire C and three switched terminals or wires 1, 2 and 3, terminals 1 and 2 being connected to normally open contacts and terminal 3 being connected to normally closed contacts. This switch is provided with a molded insulating case having integrally formed on its upper in ner wall three spaced pairs of spaced vertical ribs 6, 7 and 8 with the ribs of each pair thereof providing a channel therebetween to guide the vertical motion of momentary pushbuttons 10, 12 and 14. Left and right end pushbuttons and 14, or if the switch is used vertically, upper and lower pushbuttons 10 and 14 are alike and generally T-shaped at their upper portions having an upper flat surface for engagement by the finger of the user and each is provided with a lateral arm 10a, 14a having a downward lug 10b, 14b thereon for retaining the upper end of a helical return spring 16, 20, respectively. The lower ends of these compression springs 16 and 20 abut the upper surfaces of respective shelves 22 and 24 integrally molded at substantially the centers of the left and right ends of case 4, the upper surfaces of these shelves having suitable shallow recesses for retaining the lower ends of these compression springs. 
     As shown in FIG. 4 which is a left side view of pushbutton 10, for example, the right side of pushbutton 14 having the same appearance, the central portion 10c of this pushbutton 10 is generally flat and has a width sufficient to allow the rear edge thereof to slide in the channel between ribs 6 in the case whereas the lower end portion 10d is narrower to provide clearance for the stationary contacts hereinafter described. As shown in FIG. 1, pushbutton 14 has similar parts 14a-14d except that it is rotated 180 degrees with respect to pushbutton 10. 
     Center pushbutton 12 is also provided with a generally flat central portion 12a having a width sufficient that its rear edge will slide in the channel between ribs 7 in the case. The lower portion of pushbutton 12 is provided with dual contact operating means. This means comprises a pair of left and right offset legs 12b and 12c that extend adjacent the lower ends of pushbuttons 10 and 14 for operating both ends of the movable contact concurrently. As shown in to FIG. 3, the lower portion 12d of pushbutton 12 is narrower the central portion 12a thereof so as to provide clearance for the connector between the normally closed contacts as hereinafter more fully described. The lower center tip of pushbutton 12 is provided with a round lug 12e for receiving the upper end of a helical return spring 26 while the lower end of this helical compression spring abuts down against the upper surface of a shelf 28 which also forms a part of the mounting means for movable contact 30 hereinafter described, this shelf 28 being integrally molded at the lower portion of and within case 4. The upper surface of shelf 28 is provided with a suitable shallow recess for retaining the lower end of compression spring 26. 
     Movable contact 30 is of the single pole doublethrow type. As shown in FIG. 5, it is a generally flat spring of the leaf spring type having a generally rectangular main or terminal portion 30a having left and right contacting portions 30b and 30c extending in opposite directons rections from the ends thereof and integral therewith, these contacting portions being bent to upward angles of about 20 degrees as shown in FIG. 1 and having contact tips 30d and 30e of good electrically conductive metal on both sides of the tips thereof which engage the stationary contacts as hereinafter described. Movable contact 30 also has a flared-entry notch 30f at the rear edge centrally of its center rectangular portion 30a as shown in FIG. 5 for locking the movable contact against unwanted lateral movement in case 4 as hereinafter described. 
     Case 4 is provided with integrally molded mounting means for movable contact 30 which allows easy and fast assembly of the movable contact in the case by merely pressing it therein. For this purpose, case 4 is provided with the aforementioned integrally molded shelf 28 having downwardly turned left and right ends 28a and 28b as shown in FIG. 1 and a pair of spaced lower shelves 32 and 34 closely below and within the downwardly turned ends 28a and 28b of upper shelf 28. To securely hold movable contact 30 between shelves 32 and 34 on the one hand and downwardly turned tips 28a and 28b of upper shelf 28 on the other hand, the upper surfaces of shelves 32 and 34 are arranged on substantially the same plane as the lower surfaces of downwardly turned ends 28a and 28b of upper shelf 28. With this arrangement, it is necessary to flex or upwardly bias the central portion of movable contact 30 in order to insert it between the aforementioned shelves whereafter it may be pressed down into its place. Case 4 is also provided with a short vertical rib 36 between shelves 28, 32 and 34 which is embraced by notch 30f of the movable contact when the movable contact is pressed into its place in the case thereby to prevent lateral movement of the movable contact. 
     This switch is also provided with a plurality of stationary contacts electrically connected to terminals or wires 1, 2 and 3. of these stationary contacts is like that shown in FIGS. 1 and 6. Since all of these stationary contacts are alike, stationary contact 38 will be described in detail. As shown therein, stationary contact 38 has a mounting plate 38a having a square hole 38b therein through which an integrally molded projection 39 in the case extends and which may be heat formed over plate 38a to secure the stationary contact in the case. As shown in FIG. 1, stationary contact 38 is secured to the inner back wall of the case. Stationary contact 38 also has a forwardly projecting narrow contact strip 38c bent perpendicular from its mounting plate 38a which has secured to the upper center surface thereof a good electrically conducting contact tip 38d as shown in FIG. 6 for engagement by the lower contact tip 30d of the associated movable contact. Terminal or wire 1 is electrically connected as by welding to mounting plate 38a of stationary contact 38 as shown in FIG. 1. 
     Common terminal or wire C is electrically connected as by welding to central rectangular portion 38a of movable contact 30 as shown in FIG. 5. 
     Stationary contact 40 at the lower right-hand portion of switch case 4 is similar to stationary contact 38 and is similarly mounted in the switch case so that it need not be further described. As will be apparent, stationary contacts 38 and 40 are of the normally open type with respect to movable contact tips 30d and 30e. In this switch there is also provided a normally closed stationary contact consisting of a pair of stationary contacts 42 and 44 electrically connected to one another by a connector strap 46 as shown in FIGS. 1 and 7. The opposite ends of connector strap 46 are preferably welded to the mounting plates of stationary contacts 42 and 44 at points 46a and 46b as shown in FIG. 7 with the stationary contacts 42 and 44 being spaced correctly apart from one another so that this assembly can then be placed with the plastic projections in the case projecting through the square holes in these stationary contacts and heat formed thereover to securely mount this stationary contact assembly in the case as hereinbefore described in connection with stationary contact 38. Since stationary contacts 42 and 44 are connected together by connector strap 46, only one terminal or wire 3 is required and is welded to the mounting plate of stationary contact 44 and extends out through a hole in the case as do the other wires 1, 2 and C. 
     As shown in FIGS. 2, 19 and 20, cover 48 is provided with a pair of round pins 48a and 48b that extend inwardly from its inner surface and are inserted through respective round holes in projections 50 and 52 to permanently secure the cover to the case. As shown in FIG. 19, the inner surface of cover 48 is provided with three spaced pairs of spaced apart and vertically arranged ribs 48c, 48d and 48e that are directly opposite rib pairs 6, 7 and 8 in the case so as to provide channels therebetween along which the three pushbuttons slide thereby to guide the pushbuttons, in their operations. The inner surface of cover 48 is also provided adjacent its upper edge with four integrally molded pins 48f, 48g, 48h and 48j which extend into respective and complementary blind holes 54-57 in the case to securely position the cover with respect to the case. Cover 48 is also provided with four pairs of stationary contact retaining lugs 48k-48n with these pairs of lugs being located with respect to the four stationary contacts 38, 40, 42 and 44. The tips of each pair of these lugs such as 48n are flared to facilitate receipt of the forward end portion 38 e shown in FIG. 6 between the lugs of the pair and retaining the same securely therein. Cover 48 is also provided with a pair of countersunk holes 48p and 48q for receiving the forward end portions of the two integrally molded pins 58 and 59 in the case, these holes being countersunk on the inner surface of the cover to facilitate entry of these pins when the cover is assembled on the case. Mounting means such as three spaced projections 60 on the back of the case are used to mount the switch in an enclosure or the like. 
     A practical use or application of the switch of FIG. 1 could be for forward of reverse operation of an electrical device such as a motor and stopping the same. Depressing pushbutton 10 provides forward operation of the motor. For this purpose, common terminal C is connected to forward terminal 1 while power line terminal 3 remains connected to common terminal C. On the other hand if pushbutton 14 is depressed, reverse operation of the motor will be attained. For this purpose, common terminal C will be connected to reverse terminal 2 while line terminal 3 remains connected to common terminal C. If pushbutton 12 is depressed, line terminal 3 will be disconnected to disconnect power from the switch. This switch may be arranged such that depression of pushbutton 12 will only separate the movable contacts from the normally closed stationary contacts 42 and 44 and will not close them with normally open stationary contacts 38 and 40. However, even if the movable contacts should close to normally open contacts 38 and 40, nothing will happen because line terminal 3 has been disconnected thereby disconnecting power from the switch. 
     Referring to FIGS. 8-10, there is shown a second version of the multi-position selector switch which is a two-position START-STOP selector switch. In FIGS. 8-10, reference characters like those in FIGS. 1-7 have been used for like parts. as shown therein, this version of switch has a case 4 and a cover 48 closing the open front of the case like those in the first version of the switch. Inside the case, there if also provided a momentary pushbutton 10 and a return spring 16 like those in FIG. 1. Furthermore, there is provided a stationary normally open contact 40 connected to terminal or wire 2 similar to that in FIG. 1. In addition there is provided a movable contact 30 mounted in the case between shelves 28, 32 and 34 in the same manner as hereinbefore described. While return spring 26 is like that in FIG. 1, pushbutton 62 is a modified pushbutton which has a central flat portion 62a like portion in FIG. 12a in FIG. 1 but its lower portion is modified in that it has only one offset leg 62c similar to leg 12c  in FIG. 1 but the other offset leg similar to 12b in FIG. 1 has been deleted as unnecessary. Push button 62 also has a reduced lower end portion 62d similar to portion 12d in FIG. 1 since no modification of that portion is necessary. Since this is a two-position selector switch, it is desirable to have pushbuttons 10 and 62 adjacent one another and, therefore, the space provided in case 4 for a third pushbutton has been filled by a plug 64. As shown in FIG. 10, this plug 64, has a wide flat upper portion 64a a narrow intermediate portion 64b that fits into the slot in the case and a slightly wider lower portion 64c that prevents withdrawal of the plug when the cover has been assembled. 
     One possible use or application of this two-position selector switch would be for starting and stopping an electrical device such as a motor. For this purpose, when pushbutton 62 is depressed normally open contact 40 is closed to establish a circuit between common terminal C and terminal 2 for motor starting purposes. The electrical current to the motor flows from terminal 66 through normally closed contact 42. Therefore, when it is desired to stop the motor, pushbutton 10 is depressed to open normally closed contact 42 thereby to disconnect power from the motor. It will be apparent that these two pushbuttons 10 and 62 are of the momentary type in that when the pushbutton is released after depression thereof, return springs 16 and 26 operate to return the pushbuttons to their normal positions. Such momentary switches are typical in motor control starting circuits because when the start button is depressed, this motor control circuit will establish a connection in shunt thereof so that the start pushbutton can then be released while the motor continues to be energized. However, the STOP normally closed contact is in series in the power circuit so that depression of pushbutton 10 will disconnect power despite the shunt connection across contact 40 thereby to stop the motor. 
     FIGS. 11-16 show a third version of the multiposition selector switch, that is, a three-position maintained selector switch, for example, having a HAND position, an AUTO and an OFF postion. As is well known in the art, operation of a switch to its HAND position preconditions the control device for hand or manual operation. Setting the selector switch to its AUTO position preconditions the control device for automatic operation. And, of course, depressing the off pushbutton, restores either the HAND or the AUTO pushbutton that may be in its operating position. 
     In the following description, reference characters like those used in FIGS. 1-10 will be used for like parts. 
     As shown in FIG. 11, this version of maintained selector switch is provided with a case 4 and a cover 48 like those in the first two versions of selector switch shown in FIGS. 1 and 8. This selector switch is also provided with a commmon terminal or wire C connected to movable contact 30 and two terminals or wires 1 and 2 connected to normally open stationary contacts 38 and 40, respectively. This switch has three like maintainable pushbuttons 68, 70 and 72, pushbutton 68 being depressible to close a first normally open contact 38, pushbutton 72 being depressible to alternatively close a second normally open contact 40 and OFF maintainable pushbutton 70 being depressible to restore either one of the other two pushbuttons to its undepressed position. It will be apparent that this is a maintained three-position selector switch where only one pushbutton may be depressed at a time. If a second pushbutton is depressed while a first pushbutton is being maintained in its depressed position, this first pushbutton will be restored to its undepressed position. 
     As shown in FIGS. 11 and 13, pushbutton 68 is generally T-shaped having an upper flat surface 68a for engagement by the finger of the user, a flat stem portion 68b extending downwardly therefrom, a slot 68c extending upwardly from its lower end to provide clearance for a pair of cam slides and a holding member hereinafter described and a cylindrical maintaining portion 68d at the upper end of slot 68c as shown in FIG. 13. Pushbuttons 70 and 72 are like pushbutton 68 so that they will not be further described. 
     This selector switch is also provided with movable contact operating means which includes pushbutton interlocking means that allows depression of only one pushbutton at a time and restores any operated pushbutton when another pushbutton is depressed. This means comprises a pair of cam slides 74 and 76 and a pair of movable contact actuating levers 79 and 80 as shown in FIG. 11. Cam slides 74 and 76 are alike but cam slide 76 is turned around 180 degrees, end for end, when it is assembled in the switch as shown in FIG. 1. In this manner, cam slide 74 will operate actuating lever 79 and cam slide 76 will operate actuating lever 80 as hereinafter more fully described. 
     As shown in FIG. 14, cam slide 74 is provided with a pair of spaced oblong holes 74a and 74b whereby it is mounted on cylindrical projections 50 and 52 in case 4 as shown in FIG. 11, these oblong holes allowing cam slide 74 to move in the right-hand direction from the position shown in FIG. 11. Cam slide 74 is also provided with three V-slots 74c, 74d and 74e extending downwardly from its upper edge along the edges of which cam followers 68d, 70d and 72d, respectively, slide when a selected pushbutton is depressed or when cam slide 74 is moved in the right or left direction as hereinafter more fully described. Cam slide 74 is also provided with an actuator lug 74f extending down from its right-hand lower portion as shown in FIG. 14 for engaging lever 79 and pivoting it clockwise to close contacts 30e and 40. Cam slide 76 is like cam slide 74 except that it is turned as aforesaid so that its actuating lug 76f is at the lower left-hand portion thereof as shown in FIG. 11 for actuating lever 80. 
     This selector switch is also provided with holding means for maintaining any depressed pushbutton in its depressed position. This holding means comprises a holding member 78 shown in FIG. 15 which is generally flat and has a pair of holes 78a and 78b whereby it is mounted onto cylindrical projections 50 and 52 in the case. As shown in FIG. 15, these holes 78a and 78b are slightly offround, that is, they have a slightly larger dimension in the horizontal direction then in the vertical direction to allow limited shifting of this holding member on cylindrical projections 50 and 52 for alignment with the three pushbuttons as hereinafter more fully described. This cam member 78 is also provided with three pairs of upstanding resilient fingers 78c, 78d and 78e with each pair of these upstanding fingers having a keyhole slot 78f, 78g and 78h therebetween. As shown in FIG. 15, keyhole slot 78f has a flared entry 78j at its upper end which continues downwardly into a pair of spaced parallel edges 78k terminating in a slightly enlarged round hole 78m. It will be apparent that this keyhole slot 78f l is shaped and dimensioned to receive cylindrical portion 68d of pushbutton 68 at its flared upper end whereafter the two fingers 78c are biasd apart as cylindrical portion 68d moves downwardly finally snapping into hole 78m where it is retained. Since fingers 78c are resilient, cylindrical portion 68d can also be forced upwardly out of hole 78m by an edge of one of the V-slots 74c or 76e depending upon whether pushbutton 72 or pushbutton 70 is depressed next. In response to such action, cylindrical portion 68d moves upwardly between parallel edges 78k and stops in flared entry 78j. 
     Cam slides 74 and 76 and holding member 78 are stacked in case 4 with cam slide 76 being inserted first followed by holding member 78 and then by cam slide 74 as shown in FIG. 12. Cylindrical projection 52 has a larger diameter 52a at its root as shown in FIG. 12 and pin 48a on the cover also has a larger diameter portion 48k at its root as shown in FIGS. 12 and 20 so that the stacked two cam slides 74 and 76 and holding member 78 which are flat are freely held between these larger diameter portions for limited sliding movement. The other projection 50 in the case and pin 48b in the cover are similarly formed for similar purposes. 
     A top view of lever 79 is shown in FIG. 16. As shown therein, lever 79 has a traverse through-hole 79a adjacent its left-hand end whereby it is pivotally supported on pin 59 in the case as shown in FIG. 11. Lever 79 also has a pair of hubs 79b and 79c on opposite sides thereof through which hole 79a extends so that these hubs will space the active portion of the lever from the bottom of the case and from the cover to avoid interference therebetween. To provide a stop for limiting counterclockwise rotation of lever 79, hubs 79b and 79c are provided with symmetrical cutouts 79d and 79e so that cutout 79d will engage a boss 82 in the bottom of the case as shown in FIG. 11 thereby to limit counterclockwise pivotal rotation of lever 79 under the force of resilient contacting portion 30c of the movable contact to the angle shown in FIG. 11. Cutout 79e is provided in hub 79c on the opposite side of lever 79 so that a like part can be used for lever 80 at the left-hand portion of the selector switch shown in FIG. 11 and case 4 is provided with a similar boss 84 serving as a stop for the clockwise pivotal rotation of lever 80 under the force of resilient contacting portion 30b of the movable contact to substantially the angle shown in FIG. 11. Lever 79 is further provided with a bump 79f on its upper surface for engagement by the lug 74f as will be hereinafter described. 
     The selector switch of FIG. 11 operates as follows. As will be apparent, this switch is shown in FIG. 11 in its off position with OFF pushbutton 70 depressed and maintained in its depressed position by cylindrical portion 70d thereof being held in keyhole slot 78g of holding member 78. In this condition, both contacts 38 and 40 are normally open. To set the selector switch in one of its operating positions, pushbutton 72 is depressed. As a result, cylindrical portion 72d of pushbutton 72 bears against the angular edge of slot 74e and slides down therealong to move cam slide 74 in the right-hand direction until cylindrical portion 72d of the pushbutton is trapped in keyhole slot 78h of holding member 78. As cam slide 74 moves in the right-hand direction as aforesaid, the left-hand angular edge of V-slot 74d thereof bears against cylindrical portion 70d of OFF pushbutton 70 to restore the same to its up position. Also, when cam slide 74 is moved in the right-hand direction, its lug 74f engages bump 79f of lever 79 to pivot the same clockwise and bias movable contact tip 30e into closing engagement with stationary contact 40. In this position, lower edge 74g of lug 74f abuts the upper left portion of bump 79f to hold this lever in its clockwise operated position. Also cylindrical portion 72d of pushbutton 72 will be held in the lower end of keyhole slot 78h of holding member 78 to maintain contacts 30e and 40 closed until such time as another pushbutton is depressed. 
     If OFF pushbutton 70 is now depressed, the reverse action of that just described takes place. For this purpose, cylindrical portion 70d of pushbutton 70 will slide down the left-hand edge of the V-slot 74d to move slide cam 74 back to its left-hand position shown in FIG. 11. As a result, the right-hand angular edge of the V-slot 74e will restore pushbutton 72 to its up position shown in FIG. 11 and lug 74f will release lever 79 so that this lever will be pivoted back counterclockwise to its original position under the force resilient contacting portion 30c of the movable contact. As a result, the switch will be restored to its off position shown in FIG. 11. 
     If pushbutton 68 had been depressed next rather than OFF pushbutton 70, the action will be similar to that hereinbefore described in connection with depression of pushbutton 72 except that cam slide 76 will be moved in the left-hand direction while cam slide 74 remains in its original position. As a result, lug 76f will engage lever 80 and pivot it counterclockwise to close contacts 30d and 38. Cylindrical portion 68d of pushbutton 68 will now be retained in the lower end 78m of keyhole slot 78f of the holding member to maintain the contacts closed. The difference in this action is that since pushbutton 72 rather than 70 was down, the depression of pushbutton 68 will raise pushbutton 72 back to its normal position shown in FIG. 11. Thus, when pushbutton 68 is depressed, the right-hand angular edge of the V-slot 76c will bear against cylindrical portion 72d of pushbutton 72 to raise it out of the bottom of keyhole slot 78h up to its flared uppermost end. 
     From the foregoing it will be apparent that only one pushbutton can be pressed at a time and when a second pushbutton is depressed, the first one will be restored to its uppermost position. 
     Since the rear and forward edges of the pushbuttons are confined in the channels between the pairs of vertical ribs in the bottom of the case and on the cover as hereinbefore described in connection with FIGS. 1 and 8, it will be apparent that some slack between the parts is needed to avoid binding which, if it occurred, might prevent smooth operation of the pushbuttons. For this reason, holes 78a and 78b on holding member 78 shown in FIG. 15 are made slightly off-round, as hereinbefore described, in the horizontal direction to allow limited left or right shifting of this holding member to accurately align its keyhole slots with the cylindrical portions of the pushbuttons thereby to avoid the possibility of such binding which might affect smooth operation of the switch. 
     FIGS. 17 and 18 show a fourth version of the multi-positions selector switch, that is, a three-position selector switch which has a momentary contact and a maintained contact and which could be used for TEST-OFF-AUTO operation or the like. In FIGS. 17 and 18, reference characters like those used in the previous three versions of selector switch have been used for like parts. As shown in FIGS. 17 and 18, this version of selector switch is provided with a case 4 and cover 48 which is similar as those used in the other three versions. Also, this switch has a movable contact 30 and normally open stationary contacts 38 and 40 similar to those used in the versions of FIGS. 1 and 11 with stationary contact 40 being also used in the version of FIG. 8. Also, this version of selector switch has terminals or wires 1, 2 and C similar to those previously illustrated and described. This version has a momentary pushbutton 10 along with its bias spring 16 similar to those used in the versions of FIGS. 1 and 8. Also, this version of selector switch has maintained pushbuttons 70 and 72 similar to those shown in FIG. 11. Furthermore, this selector switch has a contact operating lever 79 like that shown in FIG. 11. This selector switch differs in its parts, however, in that it uses a holding member 78&#39; which is like that shown in FIG. 15 except that the left-hand thereof has been cut off at the broken line x shown in FIG. 15 avoid interference with and to provide space for momentary pushbutton 10. Also, cam slide 74&#39; is similar to cam slide 74 shown in FIG. 14 except that the left-hand end thereof has been cut off at broken line y shown in FIG. 14 to avoid interference with and to provide space for momentary pushbutton 10. Because the other cam slide 76 that is used in FIG. 11 is not used in this version of the switch, in order to allow use of the same case and cover, its space has been taken up by providing a pair of washer-like spacers behind holding member 78 such as spacer 88 shown in FIG. 18, this spacer having the same thickness as cam slide 76. From the foregoing, it will be apparent that pushbutton 10 operates in the same manner to close contacts 30d and 38 as hereinbefore described in connection with FIG. 1. Also maintained pushbuttons 70 and 72 operate cam slider 74&#39; and lever 79 to close and reopen contacts 30e and 40 in the same manner as hereinbefore described in connection with FIG. 11. 
     While at least one example has heretofore been given as to the practical application and use of each of the four versions of multi-positioned selector switch described, it will apparent that they have a large number of other uses depending upon the type of system or circuit in which they are desired to be used. 
     While the apparatus hereinbefore described is effectively adapted to fulfill the objects stated, it is to be understood that the invention is not intended to be confined to the particular preferred embodiment of multiposition selector switch assembly means disclosed, inasmuch as it is susceptible of various modifications without departing from the scope of the appended claims.