' ROTARY SELECTOR SWITCH Filed May 24, 1944 2 Sheets-Sheet 1 A HMV Riom@ Nov. 12; 1946. H, R, WARNK'E 2,411,013 ROTARY SELECTOR SWI TCH Filed May 24, 1944 2 Sheets-Shee’c 2 Patented Nov. 12,1946 2,411,013 UNITED STATES PATENT C‘FFICE 2,411,013 ROTARY SELECTOR SWITCH Herbert R. Warnke, East Orange, N. J., assignor to United States Instrument Corporation, East Orange, N. J., a corporation of New Jersey Application May 24, 1944, Serial No. 537,088 8 Claims. (Cl. 200-11) 2 This invention relates to electrical switches and more particularly to a multi-position selec Figure 3 is a sectional View on line 3-3 of Fig ure 1; Figure 4 is a sectional view on line 4_4 of Fig tor switch for use in inter-communication sys tems, signal systems and thelike where a com ure l; pact selector switch enabling connection with Figure 5 is a View similar to Figure l but with i all of the individual terminals except one omit one of a multiplicity of circuits is desired. It is the general object of the present invention to provide a rotary selector switch of a compact ted for clarity, and with the auxiliary Contact arm broken away to expose the main contact arm; design having low contact resistance, large cur rent capacity, rugged construction,'and long life. 10 More particularly, it is an object of the inven tion to provide a rotary selector switch having Figures 6, 7, 8, and 9 are detail views illustrat " ing, in plan, the auxiliary contact arm, the main contact arm, the common terminal, and the con tact support disk, respectively; one or more banks or decks oi terminals, the ter minals of each bank being arranged in circular Figure 10 is a rear elevation of the base plate spaced relationship, and having a common cen 15 illustrating the switch indexing means seen in ’ side view in Figure 2; and tral terminal and a rotating contact arm with means thereon for maintaining constant sliding Figure 11 is a sectional view on line II-II of Figure 10. engagement with the common terminal and other means thereon for successively engaging In order to facilitate an understanding of the the individual terminals as the contact arm is 20 invention, reference is made to the embodiment thereof shown in the accompanying drawings, rotated. A particular feature of the invention and detailed descriptive language is employed. lies in the provision of a solid silver contact mem ber, carried on the afore-mentioned contact arm, which bridges the space between the annular common terminal and the individual terminals, serving as a direct and short path of high cur 25 rent carrying capacity. It will nevertheless be understood that no limita tion of the invention is thereby intended and that various changes and alterations are contem plated such as would ordinarily occur to one skilled in the art to which the invention relates. Referring now to Figures l, 2, and 3, it will be Another feature of the invention lies in the seen that the switch comprises generally a base provision of an auxiliary contact arm, electrical ly connected to the iirst Contact arm and also 30 plate I [l in which a shaft I I is rotatably mounted by means of a bushing I2, a handle I3 being pro adapted to engage the individual terminals suc cessively, providing a second current path be vided for turning the shaft II, and one or more tween the common terminals and the individual (in the present case, two) generally annular ter minal supports i4 of suitable rigid insulating terminals. ït is also a feature of the invention that the several sliding contact members are of 35 material, such as Bakelite, each of which is pro solid coin silver, providing high current-carrying vided with a plurality of terminals I5, which capacity, low contact -resistan-ce and long life. may be of bronze coated with silver. The ter minals I5 may be secured to the supports I4 by The contact arms are of a metal possessing good any suitable means, as for example by hollow riv resilience and satisfactory conductance, they are adjusted in such a way as to maintain a light but ets IE. The outer ends of the terminals I5 are 40 constant spring pressure forcing the silver con inclined at an obtuse angle to the plane of the tact members into ñrm engagement with the support and are apertured to facilitate the secur contact portions of the respective terminals, the ing of conductors thereto. The inner ends of the adjustment being such that the resilience of the terminals I5 lie iiat against the adjacent surface contact arms will serve to compensate for any 45 of the support I4 and serve as contact portions wear of the contact members or terminals. of the respective terminals, for engagement with Other and further features and objects of the invention will be apparent from the description which follows, read in connection with the ac the contact means to be described. The supports ill are maintained in spaced relationship by companying drawings, in which: means of the bolts I'I and spacers I8. ' That portion of the shaft I I which lies inwardly Figure l is a rear elevation of a switch con. of the base plate I0 is flattened as at I9 and car structed in accordance with the present inven ries the indexing disk 20 and the rotating contact tion; supports 2|, which latter are comprised of disks Figure 2 is a side elevation of the switch of insulating material, such as Bakelite, of sub shown in Figure 1; . . ,‘ 55 stantially the diameter of the central openings in 50 2,411,013 3 the terminal supports U3. As best seen in Figure 4 a common terminal 22, preferably of bronze, annular in form, is secured to the terminal sup port lêi surrounding and partially overlying the central opening of the latter andthe contact sup 5 4 nism just described, when the handle I3 is grasped and the shaft turned to a selected posi tion, the disk 20 will be rotated, each successive tooth passing under the rollers 33 forcing the le vers 3l outwardly against the pressure of the springs 3d, and each successive valley passing un port disk 2l which rotates within said central opening. The common terminal 22 is provided der the rollers 33 permitting the levers to swing with an extension 22’ (Figures l and 3) for con inwardly again. Thus when the selected position nection to a conductor. is reached, the rollers 33 are firmly seated in the The main contact arm 23, which is shown in de 10 ,corresponding valley of the disk Zû and the switch tail in Figure 7, is mounted on .the contact sup is firmly maintained in the selected position un port 2|, and spaced therefrom, by rivets 24, andv til positively actuated. In the illustrated embodiment, the switch of the cured thereto in any suitable manner. In the il present invention is especially adapted for an in lustrated embodiment the contact members 25 15 tercommunication or signalling system in which carries two sliding contact members 25 and 26, se and Zâ are solid coin silver and are provided on a master station is to be selectively connected their upper side with integral bosses 25', 26", ex tending through apertures in the material of the with any one of sixteen subordinate stations by major axis of the contact arm whereby they wipe the contact surfaces of the respective terminals ber in order to meet the particular purpose at hand. means of a two-wire circuit. However, switches contact arm 23, and upset or peened to secure constructed in accordance with the invention may the contact members to the arm. It will be noted 20 be adapted to a wide variety of useful purposes that the downwardly projecting portions of the and the number of decks or banks of individual contact members 25 and 26 are inclined to the terminals may be multiplied to any desired num over larger areas, reducing wear and at the same From the foregoing description it will be appar time providing a self-cleaning feature. The con 25 ent that the objects enumerated above are tact member 2E has two such downwardly pro achieved by the invention, and a compact, rugged, jecting portions, one at each end, for engagement and eiiicient all-purpose rotary selector switch is provided. with the common terminal 22 and individual ter minals l5, respectively, while the contact mem 30 - Having thus described the invention, what is ber 25 also engages the common terminal 22, but claimed as new and desired to be secured by Let not the individual terminals. ters Patent is: A second or auxiliary contact arm 2l, shown in 1. In a multi-position switch, a base plate, a detail in Figure 6 overlies and is secured to the plurality of generally annular terminal plates contact arm 23, being secured by the same rivets supported from said base plate in spaced, aligned 24 which fasten the latter to the support member relation, a plurality of .terminal members sup 2 If, and is thus in electrical contact with contact ported in circular, spaced relation on each said arm 23. The auxiliary contact arm 2l carries a terminal plate, each said terminal member hav contact member 2S, which is secured to a down ing -a contact portion, a shaft rotatably mount turned iiange 25 of the contact arm by means of ed in said base plate and extending through the integral bosses 3S as described above. The con central openings of said terminal platesa, plu tact member 28, like the others, is inclined to the axis of the contact arm, and is adapted to engage only the individual terminals I5, providing an al rality of contact supports carried by said shaft, one said contact support being substantially in the plane of each said terminal plate, a contact ternate current path between contact arm 23 and 45 arm mounted Ion each Said contact support, a the terminals l5. Thus in all there are two sil common terminal mounted on each said terminal ver contact members engaging .the common ter plate and having an annular contact portion sur minal 22, and two engaging the individual ter rounding the central opening therein, contact minals, the latter two engaging the same individ means carried on each said contact arm for slid ual terminal at any given time. Furthermore, 50 ably engaging the contact portion of the adjacent the bridge-like contact member 25 provides a .common terminal, and Contact means carried short and direct path of high current-carrying on each said contact arm for successively engag capacity between the common terminal and the ing the contact portions of the .adjacent terminal individual terminals. ’ members as said shaft is rotated. The contact arms 23 and 2i are of metal pos 55 2. In a multi-position switch, a base plate, a sessing good resilience and satisfactory current carrying capacity, for example beryllium copper, and are adjusted to exert a slight constant pres plurality of generally annular terminal plates supported from said base plate in spaced, aligned relation, a plurality of terminal members sup sure upon the contact members forcing them into ported in circular, spaced relation on each said firm engagement with the respective terminals. 60 terminal plate, each said terminal member hav Due to the length and ñexibility of «the contact ing a contact portion, a shaft rotatably mounted arms, this spring pressure, though slight, will take `in said base plate and extending .through the up any wear to which the contact surfaces may central openings of said terminal plates, a plu be subject during the lifetime of the switch. rality of contact supports carried by said shaft, 'Ilheindexing mechanism, best seen in Figure one said contact support being substantially in 10, comprises the toothed disk 2li, secured on the the plane of each said terminal plate, a contact iiattened portion I9 of the shaft l l, levers 3| piv arm mounted on each said contact support, a oted as at 32 to the plate H3, cam follower rollers common terminal mounted on each said terminal 33 carried by the levers 3 i, and tension springs 34 plate and having .an annular contact portion sur secured between the free ends of the levers 3l and rounding the central opening therein, contact studs 35 carried by the base plate i0. The val means carried on each said contact arm for slid leys formed in the periphery of the disk 20 corre ably engaging the contact portion of .the adja spond in number and spacing to the terminals I5v cent common terminal, and contact means car of. thefrespective terminal supports. It will be ried on each said contact arm for successively readily understood that by virtue of the mecha 75 engaging the contact portions of the adjacent 2,411,013 5 6 terminal members .as said shaft is rotated, said last contact means being an integral bridge-like member having a portion »adapted to slidably en gage the contact portion of the adjacent common terminal in all positions of the contact arm, thereby providing a direct and short currentJ path between said common terminal and said terminal members. 3. In a multi~position switch, a base plate, a mounted on each said contact support, a common terminal mounted on each said terminal plate and having an annular contact portion surround ing the central opening therein, contact means carried on each said Contact arm for slidably en gaging the contact portion of the adjacent com mon terminal, con-tact means carried on each said contact arm for successively engaging the contact portions of the adjacent terminal mem plurality of generally annular terminal plates 10 bers as said shaft is rotated, and means for in dexing said shaft at a plurality of positions cor~ supported from said base plate in spaced, aligned responding to said terminal members. relation, a plurality of terminal members support 5. In a rotary switch according .to claim 1, an ed in circular, spaced relation on each said ter auxiliary contact arm carried on each said con minal plate, each said terminal member having a contact portion, a shaft rotatably mounted in 15 tact support and electrically connected to the said said base plate and extending through the cen contact arm thereon, and contact means on each said auxiliary contact arm for successively en tral openings of said terminal plates, a plurality gaging said adjacent terminal members, thereby of contact supports carried by said shaft, one said contact support being substantially in the providing a second current path between said contact arm and said terminal members. plane of each said terminal plate, a contact arm 6. In a rotary switch -according to claim l, an mounted on each said contact support, a com mon terminal mounted on each said terminal plate and having an annular contact portion sur rounding the central opening therein, .contact means carried on each said contact arm for slid auxiliary contact arm carried on each said con - tact support and electrically connected to the said contact arm thereon, and contact means on each said auxiliary contact arm for successively en ably engaging the contact portion of the adjacent gaging said adjacent terminal members, thereby common terminal, and contact means carried on each said contact arm for successively engag providing a second current path between said , ing the contact portions of the adjacent terminal contact arm and said terminal members, said last means being of solid coin silver. 7. A rotary switch according to claim 4, said members as said shaft is rotated, each said con 30 indexing means comprising a toothed disk mount tact means being of solid coin silver. 4. In a multi-position switch, a base plate, a ed on and rotatable with said shaft, a lever piv otally mounted on said base plate adjacent said plurality of generally annular terminal plates supported from said base plate in spaced, aligned disk, a cam follower carried by said lever and adapted to engage the toothed periphery of said relation, a plurality of terminal members sup disk, and resilient means acting on said lever for ported in circular, spaced relation on each said maintaining said cam follower in engagement terminal plate, each said terminal member hav ing a contact portion, a shaft rotatably mounted with sai-d disk. in said base plate and extending through the cen 8. A switch as deñned in claim l, each said contact arm being of metal possessing good resil tral openings of said terminal plates, a plurality ience and satisfactory electrical conductance, and of contact supports carried by said shaft, one said contact support being substanti-ally in the each said contact means being of solid coin silver. plane of each said terminal plate, a contact arm HERBERT R. WARNKE.