Jan. 14, 1947. W. B.~-COON ELECTRIC SWITCH Filed June 2, 1945 //0 "Il l I. u.nn /¿a E 1 w, m@ „Ly Jan. 14, 1947. w. B. coON 2,414,191 ELECTRIC SWITCH /Filed June »2, 1945 2 Sheets-Sheet 2 Patented Jan. 14, 1947 UNITED STATES PATENT ÜFFîCE.2,414,191 ELECTRIC SWITCH Wiliiam E. Coon, Chicago, Iii., assigner to Simpson Electric Company, Chicago, Iii., a cor poration of Iliinois ¿application .inne 2, 1945, Serial No. 597,240 ll. Claims. 1 (Cl. 20D-6) 2 The present invention relates to electric switches and is particularly concerned with elec tric switches adapted to be used for effecting the switching necessary to connect in circuit the proper instruments, sockets, etc., in a tube tester. Referring to the drawings of which there are two sheets: Figure l is a fragmentary sectional view of a panel equipped with a plurality of switches con One of the objects of the invention is the pro vision of an improved electric switch which is very compact, which occupies a minimum amount of space, and which is adapted to be manufac tured at a very low cost. Another object of the invention is the pro vision of improved electric switches of the class described which have a special type of actuating and indicating member which is adapted to pro ject from a panel to permit the actuation of the 15 switch and to indicate its position at all times. Another object of the invention is the provision structed according to the invention and adapted to be returned to initial position by a single ac tuator; Fig. 2 is a fragmentary front elevational view of the panel with the switch structures shown in dotted lines; Fig. 3 is a side elevational view of a switch unit embodying the invention with certain parts shown in section, taken on the plane of the line 3-3 of Fig. 8, looking in the direction of the ar rows; Fig. 4 is a full size side elevational view of the switch; of an improved switch structure of the class de Fig. 5 is a similar view showing the switch in scribed which has a quick make and quick break cluding two banks of contacts; and which has a wiping action between the con 20 Fig. 6 is a sectional view taken on the plane of tacts of the switch so that the circuits are made the line 6_5 of Fig. 3 looking in the direction of the arrows; and broken with a minimum amount of arcing and so that the Contact resistance is reduced to Fig. 7 is a side elevational view of the switch a minimum. of Fig. 3 shown on a scale corresponding to twice Although the present switches are particularly 25 the size of the switch; adapted to be advantageous for certain uses men Fig. 8 is a similar side elevational view of the other side 0i the switch of Fig. 7; tioned above, I desire it to be understood that Fig. 9 is an exploded view showing the various the switches are also of general application and parts of the rotating contact member prior to may lbe used for many other purposes. Another object 0f the invention is the provision 30 their assembly; Fig. 10 is a plan view of one of the contacts of an improved electric switch of the class de carried by their rotatable contact member; scribed having a snap action and means for hold Fig. 11 is a fragmentary sectional view of the ing the switch in any of its actuated positions but switch taken on the plane of the line Il-l l of which isalso adapted to be actuated in common with a plurality of similar switches by a single 35 Fig. 8 looking in the direction of the arrows; Fig. l2 is a fragmentary view in perspective actuating device so that all of the switches may showing the structure of one of the frame mem be simultaneously returned to their initial po bers; and ~ sition. Fig. 13 is another fragmentary view in per Another object of the invention is the pro 40 spective showing the structure of the other of the vision of an improved switch structure which is frame members. adapted to be embodied in double throw or mul Referring to Figs. 3, 7 and 8, 20 indicates in tiple switches and which may include as many its entirety one 0f the switch units embodying the gangs as desired on a single elongated shaft. Another object of the invention is the provision 45 invention, a plurality of which are shown in Fig. 1. The switch unit 23 is provided with a supporting of an improved switch structure having an im frame which may consist of a pair of frame mem proved actuating member and improved indicia bers 2i, 22 of metal. For example, frame mem whereby the switch has a plurality of diiierent ber 2l consists of a strip of sheet metal having positions but only one of the indicia correspond a dat body portion 23 which is provided at each ing to its present position is visible` at any time. 50 end with a laterally turned end ñange 24 and Other objects and advantages of the invention will be apparent from the: following description and the accompanying drawings, in which simi lar characters of' reference indicate similar parts throughout the several views. - . » . . an inwardly turned attaching ñange 25 carried by the end ñange 24. The attaching ñanges are located at right an gles to the body portion 23 and are provided with 55 threaded ~bores 26 for receiving the screw bolts 21 2,414,191 3 4 gaged by a common actuator which will be fur ther described in respect to Fig. l. Spring ¿is urges the ball :i1 toward the left but preferably formed with rectangular slots 29 in permits the ball to be cammed out of the sockets their edges, leaving a pair of outwardly project ¿ii-t6 when the rotatable member 35 is turned. ing lugs 30 for engagement with the other frame The actuating disc S5 includes a circular _body member 22. portion 52 in the form of a plate of molded in The frame member 22 may consist of a sulation which is provided with a centrally lo straight piece of sheet metal each end of which cated cylindrical hub 53 and a spring housing is formed with the inwardly extending rectangu lar slots 3l adjacent the end, of such a size as 10 flange 5t extending in the same direction as the -hub and located near the periphery of the disc to receive the lugs 3l) and the body portion 32 be 52. The edge 55 of the disc 52 may be rounded tween the slots 3l is Aof sufficient width to be re and is preferably knurled as shown for conven ceived in the slot 2S of the end flange 24. Thus, ient engagement with the ñngers which actuate when these frame members 2| and 22 are as the disc by frictional contact. 15 sembled as shown in Fig. 3, the ends of the lugs The cylindrical housing flange 52 may be pro 3E may be riveted over slightly to hold the frame vided on its cylindrical periphery with numerical in assembled relation. indicia indicated at 55 (Fig. 4) showing the po The two frame members 2| and 22 are pro sition of the switch at any time. The axial length vided with a pair of aligned cylindrical bores 33, 34 for receiving the stub shaft 35 which carries 20 of the hub 53 and housing ñange 54 is such that rotatable actuating member 36 may be received the rotating actuating disc 36. The length of between the frame members 2l and 22 where it the stub shaft 35 depends upon the number of is rotatably supported by the shaft 35 engaging banks of contacts that are intended to be em in bores 33, 34, ployed upon each unit. As shown in Fig, 4, the The space between the hub 53 and housing unit may have one bank. of contacts, or, as shown flange 5G houses a spiral ribbon spring 51 which in Fig. 5, two banks, or any suitable number of is used to urge the actuating member 36 toward banks of contacts may be employed, depending on its initial position. The frame member 2l car (Fig. l) by means of which the switch units are attached tc a panel 28. The end flanges 2è are - the number of contacts which it is desired to ac tuate simultaneously. ries a metal pin 58 (Fig. 3) riveted in a bore and ' projecting into a hook 5B which is formed by ` The actuating disc 36 preferably consists of a 30 curling one end of the spring into partially cylin molded member made of a phenolic condensa tion` compound which is molded about the shaft 35 and about anchoring formations carried by a metal disc 31 that is located in the right face of the actuating disc 36. Metal disc 31 may be se cured in place by a screw bolt 38 as shown in Fig. 3 or it may have a plurality of anchoring drical form. The other end of the spring has a cylindrical formation 66 which may be slid ax ially into a cylindrical bore 6| that is formed in the housing flange 54, thus anchoring this end of the spring to the actuating member 36. The strength of the spiral spring 51 is sufficient to rotate the member A35 and its rotatable switch members cut out of its periphery and bent in members when the pressure of spring 49 is re ward to be anchored in the molded insulation of 40 leased, but as long as spring 4S presses the ball the actuating disc 36. The metal plate 31 serves as a part of the snap enough to alter the position of the rotatable mechanism and for retaining the switch in its member 35. actuated positions and this plate is provided with In addition to the sockets iii-25 for the ball a central aperture 39 that registers with the 45 E11, the plate 31 preferably has an arcuate slot G2 aperture 4U in the actuating disc 36. which is of suflicient length to determine the In addition to this, the metal disc 31 has a range of movement of the rotatable member 35. plurality of circular apertures 4I-46 (Fig. 8) Slot 62 is located to be engaged by an inwardlyA which are countersunk at their outer end so as projecting lug 53 which may form a part of frame to provide a better socket for a steel ball 41 which 50 member 22 (see Fig. 13), «being bent inwardly is located to be received in the apertures lil-45. The ball 41 is carried in a cylindrical bore 43 in the frame member 22, this bore being located at a suitable rad'usfrom the axis of shaft 35 so that the ball is adapted to be received in any from the frame member 22, to extend into the slot S2. The end Si! of slot G2 determines the limit of rotation in a clockwise direction of the rotatable switch and the end 55 of the slot t2 determines the limit of motion in a contrary of the sockets ¿ll-ß'i carried by the rotatable ac direction. tuating member 36. Ball 41 projects from itsV bore ¿t8 in the frame member 22 to engage the. metal plate 31 on the left, and on the right hand side in Fig 3 the ball is engaged by a leaf spring 49 which urges it toward the rotatable actuating member 36.` l The leaf spring 39 may be made of any suita ble »material such as spring brass or bronze, and it comprises an elongated strip of this sheet metal . In order to reduce the friction between the end of the insulating hub 53 and the adjacent frame member 2l, a washer 6‘5 is carried by the shaft 35. The left end of shaft S5 (Fig. 3) is provided with one or more non-circular portions 61 such as for example flat surfaces, and the shaft 35 is adapted to actuate a rotatable switch member 68 for each bank of contacts. In Fig. 5 this flat-- tened portion of the shaft 35 has been extended far enough to support two such rotatable switch members 58 and E9. lThe rotatable switch member 68 is shown with through Vthis flange and through the frame mem its parts in exploded form in Fig. 9 'and this ber 22 tc secure the leaf spring 49 to frame mem ber 22. The leaf spring extends longitudinally 70 member preferably comprises a disc 1@ of insulat ing material such as indurated fiber or a phenolic of the frame member 22 and thus has considera condensation molding compound.. Disc 1S is pro ble length so that it need not be bent beyond its vided with the centrally _located non-circular elastic limit. Its length is such that it projects aperture 1 l _which is complementary to the -exter-j> abovethe end ñange 24 of the switch unit, the upwardly projecting portion serving to be en 75 nai shape of the shaft 35 at its .flattened por-,-l having an enlarged attaching ñange 5i! provided with apertures for receiving the rivets 5I passing 2,414,191. tionsßß'I‘. The disc T0 is preferably provided with a plurality of partially` circular apertures 'I2 which are substantially rectangular in shape but are arranged along the line of a circle, these slots being adapted to receive the securing members that are carried by a pair of annular Contact members 13, M, (i construction and these preferably comprise resil ient sheet metal members which are bent back upon themselves at the connector portion Sd which is provided with a T~shaped formation and with an aperture 95 for receiving a connecting wire. At an intermediate point each connector is secured to the arcuate insulating plate 86 (Fig. Each annular contact member comprises a flat ll) by a tubular rivet 96 which passes through sheet metal member in the form of an annulus both the insulating plate and the contact mem» and having a plurality, auch as for example four, ber. inwardly extending radial tabs 'I5 which are bent From the tubular rivet 96 each contact extends in an axial direction, the. axial portion being radially inward, One is bent upward at 91 and called a securing tab ‘IS and being provided with the other is bent downward at 98 to give these an axially' extending` slot ll, The securing tabs contact portions a spread. Then the contact por ‘i6 are wide enough and thickv enough to fit in I tions are bent until theyv extend into engage the slot ’I2 and theyA are properly located to regis ment IBO and with eacheach of the other corners at the ISI end is bent portions outward terA with four of these slots. Thus. the annular contact plates 'I3 and 'I4 may so that the two legs of each contact engage each .be secured to the opposite sides of the insulating other but the corners have a spread for the pur disc 'IB by passing the securing ta'bs TIB through 201 pose of guiding the contact member 93 carried by predetermined slots 'I2 and by spreading the ax annulus 'I3 between them. This spread of the ially extending slots il. The annular contact fixed contact portions assures the contact 93 en members 'I3 and *Ill are of such size that only the tering between them and wiping across both of innermost portion of these annular members rests the legs of each ñxed Contact. on the faces of the insulating disc ‘lil and thus Referring now to Figs. 1 and 2, here the panel the annular members 'i3 and 'I4 project beyond 23 is provided with a plurality of apertures IEiZ, the edge 'i3 of the insulating disc 1B. Since the each aperture consisting of an elongated portion tabs 'I6 may be located in spaced slots 12, the for exposing the knurled edge 55 of the actuat two annular members 'I3 and 'Ill may be insulated incr disc 3b and each aperture also including a from each other and if desired each of these an small rectangular portion for exposing an indi nular members might be used for a contact. eating numeral on the hub 54. The threaded However, in the embodiment of Fig. 3 only the bores 26 in frame member 2i serve to receive the outermost annular member 'i3 has been used for l screw bolts 2l which secure the switch units to a contact while the other annular member ‘It the rear side of the panel with nothing but the merely serves as a guide for holding the rotatable 35 edge of the actuating disc and the indicating switch member 68 upon the shaft 35. This is numerals exposed on the front side of the panel. accomplished by means of the switch contact Allof the upwardly projecting end portions of bank 'i9 (Fig. 7) which carries a multiplicity of the leaf springs 49 are located in alignment and ñxed contacts Bil-25, The contact bank 19 cori these are adapted to be engaged by metal discs sists of a plate of insulating material such as a 40 "i3-|05 (Fig. l) carried by a reciprocating actu» phenolic condensation compound. which is arcu ating rod I'fllì. rï‘he rod IBS is guided by being ate in shape, the arcuate portion 85 being sub slidably mounted in cylindrical apertures in the stantially concentric but spaced from the rotat angle brackets IWI-_|539 which are secured to the able switch member 68. panel 28 by screw bolts and the discs IGS-HB5 are At each end the arcuate portion 85 has an enn located on the left side of each leaf spring 49 largement 8'I provided with apertures for receiv having reference to Fig. 3. ing the screw bolts 88 which pass through these A helical compression spring Il@ is interposed apertures and are threaded into the frame mem between the bracket I E8 and a washer I I I on the ber 2 I. An insulating spacer washer 89 is carried rod |06, the washer being in engagement with a by each bolt 88 to space the bank 'I9 properly from 50 transverse pin II 2’. The coil spring H0 urges the frame member 2i so that the contact annulus the rod |06 toward the left and urges the discs 'I4 is spaced from frame member 2l. Adjacent ‘each end of the arcuate member S5 there is also an inwardly extending insulating lug Bil, 9| which extends radially toward the insulat- ; ing disc 'I0 and is of suiiicient thickness to haverv a sliding ñt between the annular members 'I3 and ’i4 at the edge ‘I8 of disc l0. It is these lugs 538, 9| which guide the annular members 'I3 and 'M of the rotatable switch member 'lil and hold this switch member on the shaft 35. ' A third such lug 92 projects radially inward from the arcuate portion 86 between the annularvcontacts 'i3 and 14. The annular member 'I3 serves as a continuous contact for engaging. the fixed contact member and -the ñxed contact member 85‘ is located closer to the axis of the shaft 35 so that it will be in engagement with the annulus 13. The other fixed contact eil-_84' are. located. at a greater radius so that they are out of contact with the annulus 'I3 butare positioned toengage a radially'Y extending contact portion 93 which is carried by theannuluszlßfiy. x .1. . ' 1 r - , . e r .'z. All of the'contactsgßß--Bñ may be identical ' IUS-|05 out of engagement with the leaf springs 49. A bracket H3 carried by panel 28 has a bell crank H4 pivotally mounted by a rivet IIS with one arm I I6 in position to engage the end of rod |06. A push button II'I is slidably mounted in a threaded plug II8 carried by panel 28 and is confined against outward movement by a trans verse pin I I 9. A plunger rod I20 of the push but ton II'I is located to engage the other arm i2I of the bell crank but a coil spring I22 urges the push button outward into the position of Fig. l. In some embodiments of the invention this spring may be eliminated. as the spring iIIl on the rod IBS may accomplish the` same purpose.. The operation of the switch units and of. the bank. of switch units is as follows: Contact 85 is the common contact which is connected to a commonv lead that is intended to be controlled by the switch and connected to any one of the other contacts Bû-Bll selectively. When the switch isv inthepositionim~ which contacteer engages.; Contact ßìiit‘is'on. open circuit with: respect to the other contacts Ste-84.. 2,414,191 8 that they may be placed within the price range If the finger is then appliedto the knurled> edge 55V of the rotatable actuating member 36, of a vast number of users. > While I have illustrated a preferred embodi this will tend to cause this member to rotate and the steel ball 41 will be cammed out of its ñrst socket 46 and will ride up over the metal mem ber 31 against the tension of the leaf spring ¿i9 which holds the ball in the aperture 48. As the ment of my invention, many modiñcations may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but de sire to avail myself oi all changes within the rotatable member 36 moves on farther, the ball - will drop into the socket 45 and will tend to hold scope of the appended claims. v Having thus described my invention, what I the rotatable member 36 in this position. In thisï 10 claim as new and desire to secure by Letters position the movable contact member 93 engages Patent of the United States is: '1. A rotatable switch member comprising a supporting member having a slot, a supporting The resistance toward movement of a ball out 15 frame carried by said member and having bear ings for a shaft, a rotatable insulating member of its socket is such that the spiral spring 5I in projecting from said slot for engagement by the the housing 54 of rotatable member 36 cannot fingers of an operator, an annular contact car overcome the resistance to movement of the ball ried by said rotatable shaft and a plurality of and the switch is held in this position. I-Iow ever, each time the switch is moved a step farther 20 fixed contacts carried by said frame and insulated from each other, and a snap retaining means for away from the contact 85, the spiral spring 5l holding the rotatable insulating member in any is wound up. of a plurality of different positions, said snap The rotatable member 36 may be successively retaining means comprising a ball resiliently brought into a position in which the steel ball ¿il is retained in sockets 44“, 43, e2, and finally 25 mounted on said frame and adapted to be en~ gaged in any one of a plurality of sockets located 4 I, during which the Contact member 93 will suc~ in said rotatable insulating member, said ball cessively engage ñxed contacts 83, 82, 8i and being movable mounted in a bore in said frame finally 30 and the movable switch member ‘lil and havin-g resilient means urging it toward will be retained in any of these positions by the the contact 84 having been inserted between vthe portions 99 and H10 of that movable contact as shown in Fig. 1‘1. steel ball lil engaging in its socket. ' Ii the operator Wishes, he may move the switch backward to any desired position and at any time the position of the switch Will be indicated by the numeral which is exposed at the aperture |02. 30 said sockets. ' 2. A rotatable switch member comprising a supporting member having a slot, a supporting frame carried by said member and having bear ings for a shaft, a rotatable insulating member projecting from said slot for engagement by the There are some'uses of these switch units in 35 fingers of an operator, an annular contact car which it is desirable to clear the machine or ried by said rotatable shaft and a plurality of tester and move all the switches back tothe fixed contacts carried by said frame and insu initial position. In such case the arrangement lated from each other, and a snap retaining of Figs. 1 and 2 is of great advantage as it is only necessary to push the push button Ill to clear 40 means for holding the rotatable insulating mem ber in any ci a plurality of diñerent positions, all the switches. This action is as follows: said snap retaining means comprising a ball re Push button Il'l rotates the bell crank l i4 siliently mounted on said frame and adapted clockwise in Fig. 1. Bell crank il@ moves rod to be engaged in any one of a plurality of sockets lofi toward the right against spring Ilû. Discs located in said rotatable insulating member, said Ul l03--I05 engage the leaf springs 49 of the re ball being movabley mounted in a bore in said spective switch units 20, permitting the steel balls `trame and having resilient means urging it to 4l in each unit to be cammed out of whichever ward said sockets, said resilient means compris socket ¿il-d6 the ball happens to be in. Under ing a leaf spring having a projecting portion to these conditions the steel ball 41 no longer holds the rotatable actuating member 35 in a ñxed 50 be engaged for releasing the retaining action of said ball. position and the spiral spring 51 in the housing 3. A snap mechanism for retaining a rotatable 5d acts to return the rotatable switch member switch'member in any position to which it is 'lll to its initial position where the movable con moved comprising a supporting frame, an insu tact 93 engages the iixedcontact 35. Thus a 55 lating member rotatably mounted in said frame mere push on the push button H1 releases all and being provided in one of its ends with a plu of the switches to return to their initial position. rality of sockets arranged in a circle, said frame In a tube tester this is of marked advantage be having an aperture adapted to register with any cause otherwise it would require separate ma ci said sockets, a retaining ball in said aperture nipulation of each switch unit by the operator. The present switches maintain their contacts 60 and adapted to engage in said sockets and a leaf spring engaging said ball and carried by said in a bright and low contact resistance condition frame and projecting beyond the end of said and they are adapted to be moved to any one of frame for manipulation to release the ball. a plurality of positions with a minimum amount4. A snap mechanism for retaining a rotatable of eiïort. The present switch may be provided with any number of banks of contacts for simul 55 switch member in any position to which it is moved comprising a supporting frame, an insu taneous or successive operation and any number lating member rotatably mounted in said 'frame' of unitsv may be mounted on a single panel to be and being provided in one of its ends with a plu« releasedand returned to initial position by mere rality of sockets arranged in a circle, said frame ly actuating one push button. The present devices are capable of being man 70 having an aperture adapted to register with any of said sockets, a retaining ball in said aperture ufactured very economically and they utilize a minimum number of separate parts. rI‘hey may be used for a long period of time without neces' sity forv repair 'or' replacement _of any ofitheirf parts and maybe manufactured so econ'oriii'callyA` and adapted to engage in said’` sockets and a leaf spring engaging said ball andi carried by said frame and projecting beyond the erid‘of-s'aid- 75' frame for manipulation- to release the ball, said 9 2,414,191 sockets being formed in a metal plate embedded 10 9. In an electric switch unit, the combination in said insulating member. of a supporting frame having a pair of ñxed 5. A snap mechanism for retaining a rotatable frame members provided with bearings for a switch member in any position to which it is shaft, a shaft in said bearings and projecting be moved comprising a supporting frame, an insu yond said frame, said shaft having a non-circular lating member rotatably mounted in said frame formation at its projecting end, a rotatable in and being provided in one of its ends with a sulating member of disc shape carried by said plurality of sockets arranged in a circle, said shaft for actuating the shaft, an insulating sup frame having an aperture adapted to register with porting plate carried by said frame adjacent the any of said sockets, a retaining ball in said aper~ 10 projecting end of said shaft and having a plu ture and adapted to engage in said sockets and a rality of fixed contacts, an insulating disc car leaf .spring engaging said ball and carried by ried by the projecting end of said shaft and ro said frame and projecting beyond the end of said tatable with said shaft, a pair of annular metal frame for manipulation to release the ball, said members carried by said latter disc and project sockets being formed in a metal plate embedded 15 ing edgewise therefrom to form a groove and a in said insulating member, and said metal plate pair of insulating lugs projecting from said in being formed with an arcuate slot for receiving a sulating plate into said groove to hold said lat lug carried by said frame, said lug and slot serv ter insulating disc on the projecting portion of ing as stops to determine the limits of rotative said shaft, one of said fixed contacts engaging movement of said insulating member. 20 the annular portion of one of said annular metal 6. A snap mechanism for retaining a rotatable members, and the other of said fixed contacts switch member in any position to which it is being located farther outward radially to engage moved comprising a supporting frame, an insu a radially projecting contact member carried by lating member rotatably mounted in said frame said latter annular member. and being provided in one of its ends with a plu 25 10. In an electric switch unit, the combination rality of sockets arranged in a circle, said frame of a supporting frame having a pair of fixed having an aperture adapted to register with any frame members provided with bearings for a of said sockets, a retaining ball in said aperture shaft, a shaft in said bearings and projecting be and adapted to engage in said sockets and a leaf yond said frame, said shaft having a non-circular spring engaging said ball and carried by said 30 formation at its projecting end, a rotatable in frame and projecting beyond the end of said sulating member of disc shape carried by said frame for manipulation to release the ball, said shaft for actuating the shaft, an insulating sup insulating member having an axially extending porting plate carried by said frame adjacent the hub and an axially extending cylindrical hous projecting end of said shaft and having a plu ing and a spiral spring tensioned between said rality of fixed contacts, an insulating disc carried insulating member and said frame and located by the projecting end of said shaft and rotatable in said housing to return said insulating member with said shaft, a pair of annular metal mem to initial position when said ball is released from bers carried by said latter disc and projecting pressure by said leaf spring. edgewise therefrom to form a groove and a pair 7. A switch assembly comprising a plurality of 40 of insulating lugs projecting from sai-d insulating switch units carried by a panel, each switch unit plate into said groove to hold said latter insulat having a disc, the edge of which projects through ing disc on the projecting portion of said shaft, said insulating disc carried by said shaft being provided with a plurality of circular sockets in a slot in said panel and each switch unit being provided with a plurality of sockets in said disc engaged by a spring pressed ball carried by the one of its faces and a spring pressed ball carried n by said frame for engaging in any one of said switch unit frame, spring means for returning each switch unit to its initial position, movable sockets to resiliently resist rotative movement of said latter insulating disc. contact means actuated by each rotatable disc and ñxed contacts carried by each switch unit, 11. In an electric switch unit, the combination a reciprocating plunger rod carried by said panel 50 of a supporting frame having a pair of fixed and having discs for engaging a leaf spring car frame members provided with bearings for a shaft, a shaft in said bearings and projecting be ried by each switch unit for urging the ball of yond said frame, said shaft having a non-cir each switch unit into its sockets, and manual means for actuating said plunger to relieve all cular formation at its projecting end, a rotatable insulating member of disc shape carried by said of the balls of the switch units from spring pres shaft for actuating the shaft, an insulating sup sure and to permit the first-mentioned springs to porting plate carried by said frame adjacent the return each switch unit to its initial position. projecting end of sai-d shaft and having a plu 8. In an electric switch unit, the combination rality of ñxed contacts, an insulating disc carried of a supporting frame having a pair of fixed frame members provided with bearings for a 60 by the projecting end of said shaft and rotatable with said shaft, a pair of annular metal members shaft, a shaft in said bearings and projecting carried by said latter disc and projecting edge beyond said frame, said shaft having a non-cir wise therefrom to form a groove and a pair of cular formation at its projecting end, a rotatable insulating lugs projecting from said insulating insulating member of disc shape carried by said shaft for actuating the shaft, an insulating sup porting plate carried by said frame adjacent the plate into said groove to hold said latter insulat ing disc on the projecting portion of said shaft, said insulating disc carried by said shaft being projecting end of said shaft and having a plu provided with a plurality of circular sockets in rality of fixed contacts, an insulating disc carried one of its faces and a spring pressed ball carried by the projecting end of said shaft and rotatable with said shaft, a pair of annular metal members 70 by said frame for engaging in any one of said sockets to resiliently resist rotative movement of carried by said latter disc and projecting edge said latter insulating disc, said spring pressed ball being engaged by a leaf spring carried by said frame and projecting beyond said frame for wise therefrom to form a groove and a pair of insulating lugs projecting from said insulating plate into said groove to hold said latter insulat ing disc on the projecting portion of said shaft. 75 manipulation to release the pressure on said ball. WILLIAM B. COON.