US2698884A - Rotary switch contact assembly - Google Patents

Description

Jan. 4, 1955 C. T. BREITENSTEIN ROTARY SWITCH CONTACT ASSEMBLY Filed Sept. 2l, 1950 M ZQQQQOOOQQ s@ QQ QQQQQQQQQQQQQQQQ 5 2 QQQQQ OOOO United States Patent O ROTARY SWITCH CONTACT ASSEMBLY Charles T. Breitenstein, Chicago, Ill., assignor to Raymond T. Moloney, Chicago, Ill.

Application September 21, 1950, Serial No. 186,077

6 Claims. (Cl. 200-11) This disclosure pertains to rotary electrical switches and provides improvements in a contact carrier and collector ring means therefor characterized principally in that the carrier structure has a plurality of radial arms which have contact-carrying offsets disposed -angularly to the radial parts thereof, in the manner of a chord or secant.

The carrier structure is further characterized in that spring contact fingers are carried on the angular offsets in positions rendering the fingers adjustable and 1nspecttllble in relation to contact buttons over which they trave The various features of the invention pertain to the provision of a contact carrier of peculiar configuration including a hub portion adapted to be mounted with a collector means on a shaft for rotary motion, the carrier having contact offsets and contact fingers disposed angularly to radii of the shaft and hub, and collector means including a form of hub having axially extensive pins connected to the contacts on the carrier.

Additional features of novelty and utility pertain to details of the shape of the carrier, the mounting and attitude of the contact fingers thereon, the construction and operation of the collector means for connecting the contact fingers to desired circuits, and other aspects which will become apparent as the following description proceeds in view of the annexed drawing in which:

Fig. l is a perspective view of a rotary switch embodving the features of the invention;

Fig. 2 is an enlarged cross-section through the collector ring hub;

Fig. 3 is a reduced plan view of the contact carrier;

The rotary switch shown in Fig. 1 includes a contact panel mounted in upright position on base 11 by means of brackets 12.

Shaft means 13 extends centrally through the panel for connection with a driving motor (not shown).

Many contact buttons are disposed on said panel in radial alignment and concentric arcs about the axis of the shaft 13, as at 14, for connection in various circuits through leads (on the rear of the panel) from individual buttons and terminating at connection lugs 15.

A contact carrier 20, having the especial configuration shown in Fig. 3, is mounted on shaft 13 by means of a hub structure 21.

The carriers are stamped or molded from various phenolic resin insulating compositions, and as depictedl n Fig. 3, have a plurality of radially offset arms 22 upon which are secured spring contact fingers 23.

It is important to observe in Fig. 3 the configuration of the carrier and angular disposition of arms 22 with respect to a radius line I-I, with which the axis line Il-II makes the angle A, so that the arms tend to aie a chordal disposition or direction, instead of ra- The spring ngers 23 likewise have a somewhat chordal disposition and tend to project and progress over their respective circles of contact buttons 14 laterally or crosswise of a radiusvfrom the hub.

In other terms, the respective long axes of the several arms 22 are each approximately parallel to only one certain radius line (of which radius line IV is only one example).

In the embodiment shown, the provision of four symmetrically arranged carrier arms gives the carrier a ewastika-like appearance; however, it is possible to pro- 2,698,884 Patented Jan. 4, 1955 vide a different number of arms having the same angular disposition.

Means for establishing electrical connections with the several wiper fingers or contacts 23 includes a collector ring assembly 25, Fig. 1, having the construction shown in Fig. 2, which includes a hub sleeve 26 having opposite axial studs 27 which key into slots formed in the carrier hub 21 to turn with the latter.

The sleeve 26, like hub 21, is formed of insulating material and it has fitted thereon a plurality of brass washers 28 separated by insulating washers or wafers 29 of slightly greater, but uniform, outside diameter than the metal washers or rings 28, so as to insulate the latter from each other and afford .narrow .circumferential grooves, as at 30, in which the curved ends 32 of wire fingers or wipers 31 ride on their respective brass rings 28 (see Fig. 1 also). l

Connection to the several collector rings 28 is effected by means of elongated studs 35 conically headed at one end 36 into a conical seat or bore in a corresponding brass washer or ring 28, so as to project axially through aligned oversized holes in all of the succeeding washers to project beyond the assembly for soldered connection with a wire 37 (Fig. 1), which leads to, and is soldered to, the tail of one of the wiper lingers 23A, for example.

Thus, in Fig. 2, the washer 28A is provided with its axially extensive connecting stud 35, while the adjacent washer 28B is provided with stud 35B, and so-on, circlewise.

At the opposite axial ends of the assembly of alternate brass and insulating washers 28, 29, are heavy header washers 40, of insulating material, one of which (right) is stopped by shoulder 26A on the hub sleeve, while the other (left) is pressed home by a spring spider 41.

The several collector fingers 31 are mounted in operative positions between a pile of insulating spacer washers 50, Fig. l, strung on bolts 5l in angles 52 on panel brackets 12.

Connections to the collector wires or fingers 31 are made by wires, as at 53, soldered to the looped lower ends 31X of said fingers.

The collector fingers 31 have intermediate loops (not seen) fitting in between the spacer washers 50.

It will be evident from Fig. 1 that each contact spring 23 may be easily inspected in its engagement with the contact buttons in all positions around the contact bank', and that the contacting ends (as well as the terminal tails, e. g. at 23A) are accessible for any bending or like adjustment (which are frequently desirable) to ensure good contact with the buttons, so that servicing and adjusting inspection and manipulation is greatly facilitated notwithstanding that there may be as many as eight or more contact fingers on each carrier arm.

Connections with the several spring contact blades 23 on the carrier arms'are readily made and accessible on the collecting ring means 25, 31.

The manufacture of the switch structure is simple and relatively inexpensive, the carrier 20 being a punching (for smaller, light-weight devices) or a molded product.

The collector ring means is readily assembled, and is removably keyed to the carrier, and a plurality of such rotary switch assemblies (each'consisting of a carrier and collector hub assembly) may be mounted on a single drive shaft.

In addition to facilitating adjustment and inspection of the contacts, the novel switch structure overcomes an objectionable limitation existing in the older type of rotary wiper switches (which employ more or less radially extensive concentrically-assembled wipers on a hub) by reason of the fact that when a large number of radial contact lingers or wipers are stacked on a hub, the hub (with insulation) must be enlarged proportionally in its vaxial thickness with the result that the added wipers must be bent over more and more toward the contact button panel in order to engage the buttons at all, and such contacting is unreliable and troublesome.

According to the improvements disclosed, a large number of contact fingers 23 may be mounted, and they are all of uniform size, and all spaced uniformly from the face of the button panel, which is to say that the fingers may have a uniform bend toward the contact buttons because .of the flat construction of the carrier.

The iiat faces and angular attitude of the carrier arms 22 makes it possible to mount as many as ten contact lingers 23'on one arm while keeping the overall diameter of the llat carrier within the dimensional limits of a comparable rotary switch of the old type; and it is possible to mount as many as forty fingers 23 on such a carrier, whereas an old type of rot, y switch with forty radial contact blades would be ex emely cumbersome and certainly a source of service trouble.

It will 'be observed in Fig. 1 that the individual contact buttons 14 diminish in diameter in the inner rings nearest the shaft 13, so that the area of button surface exposed for engagement by the corresponding contact fin ers 23 becomes quite small in a large-capacity contact bank such as shown, requiring especially stable contacting adjustment and spring pressure for the fingers 23 in these regions for reliable service and long contact-surface life. The improved structure employs uniformly dimensioned and positioned contact fingers 23 for all sizes and positions of the buttons 14, and makes possible v ery accurate alignment even in large-scale manufacturing.

The disclosed construction makes it possible that the chordally-extending contact carrying extensions or arms 22 may all be symmetrically situated about the hub, or one or more of the same may be offset several degrees so as not to be diametrically or symmetrically opposite the arm which would otherwise be one-half 'revolution displaced therefrom, so that bridge circuits between contacts 180 apart may or may not be completed every halfrevolution, without changing the length of the contact fn ers.A

F`he accuracy of location of the contact fingers with respect to the contact points is such that little or no adjustment is necessary in assembling the switches in quantity production.

I claim: f

l. In a rotary switch, a contact carrier of flat construction including a flat plate-like hubportion from which extend integral co-planar, flat, contact arms with radially offset integral portions extending in a chordal sense symmetrically about the center of said hub in the figure of a swastika, spring-blade contact fingers mounted on the faces of said arms to extend in a crosswise sense therefrom and also in a chordal sense relative to the circle of travel of the carrier, said fingers being biased out of the plane of said carrier and arms for engagement with stationary contacts along the path of travel thereof, co1- lector contact means 'rotatable with said carrier and including connections to said contact fingers, and stationary contact means cooperable with said collector contact means for extending circuit connections several fingers.

2. A contact carrier for rotary switches, said carrier comprising a flat plate of insulating material having a central hub portion adapted to lit on a shaft and four integral contact 'arms offset from said hub portion and directed in the pattern of a swastika, contact fingers mount- `swastika-shaped body of insulating material havin ed on said arms to project laterally thereof and adapted for engagement with stationary contact elements relative to which said carrier is rotated, together with rotary contact means concentric with said hub portion and having connections with said lingers for extending circuit connections from said fingers to desired circuit terminals.

For use in rotary switches, a Contact carrier in the form of a flat plate of insulating material in the shape of a swastika, a shaft hub mounted centrally of said plate, spring-contact fingers mounted on the arms of the swastika to project laterally thereof, together with movable contact means mounted to rotate with said shaft hub and having connections extended to said fingers and adapted to cooperate with relatively stationary collector contacts forextending connections from said fingers to desired circuits.

4. A rotary contact 'carrier in the form of a rigid, ffiat, our eccentric swastika arms each of which projects in the direction of a chord of arc substantially concentric with the center of said -body in the plane thereof, said arms each having spring contact ngers mounted thereon to extend in a sense crosswise o the arm and also in the sense of a chord of arc approximately concentric with. the center of said body, the latte'r being adapted formounting to rotate about said center, said contact lingers being adapted to engage relatively stationary contacts arranged concentrically of the axis of rotation of said body.

5. A contact carrier for rotary switches comprising an integral body of insulating material including a central hub part for engagement with a rotating shaft structure, and four contact arms projecting chordally relative to said hub and the axis of rotation thereof, said arms defining substantially the pattern of a swastika, and contact means carried by one or more of said arms and positioned to trace arcuate paths concentric of said axis.

6. A contact carrier for a rotary switch comprising a unitary piece of non-conductive material having a hub adapted for attachment to a rotating means, and four contact arms symmetrically shaped and located about said hub, each arm projecting in the direction of a chord of a circle whose center is the axis 'of rotation of the hub, each arm projecting at substantially a right angle to either of two adjoining arms about the hub in the manner of a swastika; and contact means carried by one or more of said arms and positioned to describe arcuate paths about said axis in rotation of said carrier.

References Cited in the file of this patent UNITED STATES PATENTS 964,836 Austin July 19, 1910 1,731,975 Grover Oct...l5, 1929 1,737,807 Sengebusch Dec'. 3, 1929 2,171,044 Nelsen Aug. 29, 1939 2,199,775 Bassett, Ir. May 7, 1940 2,600,938 Thiel-felder June 17, 1952

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