US3736390A

US3736390A - Rotary switch assembly with printed circuit rotor and multilayer housing features

Info

Publication number: US3736390A
Application number: US00206665A
Authority: US
Inventors: Lockard J Larue
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1971-12-10
Filing date: 1971-12-10
Publication date: 1973-05-29
Anticipated expiration: 1990-05-29

Abstract

A rotary switch is provided which is adaptable for being stacked in multiple layers for multi-function use by a single control shaft. A printed circuit board and a brush member are supported in a dust-proof housing in contacting relation and means are provided for rotating one of the board and the brush relative to the other to any of a predetermined number of distinct positions. Additionally, the inputs and outputs of the switch are all aligned in a single plane.

Description

I United States Patent 91 1 3,736,390 Lockard 1 Ma 29 1973 [54] ROTARY SWITCH ASSEMBLY WITH 3,504,139 3 1970 Long ..200 11 TW PRINTED CIRCUIT ROTOR AND :1 1: p ZOO/66 SD X aine et a MULTILAYER HOUSING FEATURES 2,894,096 7/1959 Schacht ..200/11 G X [75] Inventor: Joseph LaRu'e Lockard, Harrisburg, 3,478,180 11/1969 Bang ..200/14 X Pa. Primary Examiner-J. R. Scott I [73] Assignee: AMP Incorporated, Harrisburg, Pa. w Grefe 22 Filed: Dec. 10,1971 Gerald Klta 2 [21] Appl No 06,665 ABSTRACT [52] U 8 Cl 200/ DA 200/14 200/ G A rotary switch is provided which is adaptable for 200/l66 CT zoo/I68 being stacked in multiple layers for multi-function use [51 I Cl 01h 19/58 iiolh 21/78 by a single control shaft. A printed circuit board and a i 200/11 14 166 SD brush member are supported in a dust-proof housing 1 8 K 1 1 3 H K 1 in contacting relation and means are provided for l v G 1 T rotating one of the board and the brush relative to the other to any of a predetermined number of distinct v positions. Additionally, the inputs and outputs of the [5 6] References cued switch are all aligned in a single plane.

UNITED STATES PATENT-S 32 Claims, 11 Drawing Figures 3,558,834 l/l97l Zielke ..200/11 TW Patented May 29, 1973 3,736,390

2 Sheets-Sheet 1 Patented May 29, 1973 2 Sheets-Sheet 2 ROTARY SWITCH ASSEMBLY WITH PRINTED CIRCUIT ROTOR ANI) MULTILAYER HOUSING FEATURES BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to rotary switches and more particularly to an improved multilayer rotary switch of compact construction for highdensity switch applications.

2. Prior Art In the past, rotary switches have been bulky and heavy usually hand-constructed items which were difficult to wire and were subject to being easily damaged if accidentally dropped, or even by dust and dirt in the storage or operational environments thereof entering the switch housing and causing short-circuiting to occur therein. These former switches accordingly were not entirely satisfactory for high-density applications for these reasons, but more primarily because of their size which normally precluded the use of a plurality of such switches being used together to accomplish multiple functions simultaneously and because the inputs and outputs thereof were not aligned, such that a large area was needed to provide suitable connections thereto. With the advent of integrated and miniaturized circuits, a need now exists for a compact and compatible rotary switch capable of satisfying the requirements incidental thereto.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a novel and improved rotary switch of compact construction for use in high-density switch applications.

Another object of the present invention is to provide a rotary switch which is compact, easily assembled at low cost, and yet which is not readily subject to being damaged.

Still another object of the present invention is to provide a rotary switch being encapsulated to prevent access of dust or dirt and thereby being substantially safe from being short-circuited therewithin.

Yet another object of this invention is the provision of a rotary switch of compact construction designed to facilitate stacking with like switches to permit an increased number of functions to be performed through operation of a single control knob in a minimum amount of space.

A further object of the invention is the provision of .a compact coded rotary switch which is dust-proof, less complex and expensive to manufacture than present coded switches, less subject to damage, and being readily coupled in stacked relation with similar switches to increase the number of functions which may be performed through a single control in a minimum amount of space.

Yet a further object of this invention is the provision of a compact decimal version rotary switch being dust proof and not readily subject to damage, and being stackable with similar switches to permit an increased number of functions to be performed through operation of a single control shaft, while having minimum space requirements. t

The foregoing and other objects are attained according to one aspect of the present invention by a rotary switch, the parts of which generally are composed of plastic materials, comprising a coded printed circuit board rotatably disposed in a given plane in a dustproof housing, a plurality of elongate brush members associated therewith being fixedly secured in the housing so that the brush end thereof is always pressed against the printed circuit board with the other end extending from the housing and lying in the same plane as the board, and an operating shaft projecting from the housing being perpendicularly oriented relative to the printed circuit board and connected thereto for rotating the same from outside the housing. Within the housing, the operating shaft is connected to the printed circuit board through a disc-like member positioned on the shaft in parallel relation with the board for being rotated therewith in conjunction with the board and having compressible tabs formed on the periphery thereof which engage a plurality of detents formed in a circular pattern on an inside wall portion of the housing, whereby the shaft may be turned to place the rotatable printed circuit board in a plurality of distinct positions wherein different coding functions are established between the printed circuit on the board and the brushes. The housing exterior is further designed so that a plurality of the housings may be readily secured together in an end-to-end, or stacked, relation such that a corresponding plurality of printed circuit boards may be simultaneously rotated by a single operating shaft projecting through all of the housings to increase the number of functions that may be accomplished by maneuvering a single control knob.

In another aspect, the rotary switch of the present invention is embodied in a decimal version, wherein a fixed printed circuit board is provided within the housing and a brush member connected to the operating shaft is rotatably disposed thereon.

BRIEF DESCRIPTION OF THE DRAWINGS Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description when considered in connection with the accompanying drawings, in which like reference characters designate like or corresponding parts throughout the several views, and wherein:

FIG. 1 is an exploded perspective view of a switch constructed according to the present invention illustrating the arrangement of the various elements thereof in which they will be assembled, including the housing, a coded printed circuit board, a plurality of brushes associated therewith within the housing and a control shaft designed for rotating the coded printed circuit board;

FIG. 2 is a perspective view of the interior of one end cover of the housing shown in FIG. 1, illustrating the detents formed therein, and an internal gear adapted to be disposed therewithin for rotary movement between these detents;

FIG. 3 is a perspective view of the interior of another embodiment of a housing end cover, similar to that shown in FIG. 2, but being provided with stop members for preventing full revolution of the control shaft;

FIG. 4 is a side elevational view in cross section of the switch illustrated in FIG. 1 being shown in its assembled condition, with a control knob affixed to the projecting end of the control shaft;

FIG. 5 is a sectional view of the switch shown in FIG. 4, taken along the line AA thereof, wherein the detented housing end cover of FIG. 2 is employed;

FIG. 6 is a sectional view of the assembled switch shown in FIG. 4 taken along the line AA thereof, wherein the detented housing end cover having stop members integrally formed therein is employed;

FIG. 7 is a perspective view of a stacked array of a plurality of the switch assemblies illustrated in FIGS. 1 and 4;

FIG. 8 is a side view of a portion of the switch shown in FIGS. 1 and 4, illustrating one manner of providing an electrical connection to a terminal of a brush member thereof;

FIG. 9 is a perspective view illustrating another manner of providing electrical connection to the terminals of the brush members of the switch shown in FIG. 1, wherein the pin sections thereof are bent back to receive posts;

FIG. 10 is an exploded perspective view of another embodiment of a switch constructed according to the present invention, wherein a decimal version printed circuit board is provided; and

FIG. 11 is a side elevational cross-sectional view of a portion of the switch illustrated in FIG. 10, showing the connection of a circular spring-like brush member to the printed circuit board thereof.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS Referring-now to the drawings, and more particularly to FIG. 1 thereof, a housing for the switch of the present invention is shown being composed of three separate pieces, preferably constructed of a plastic material either by molding or stamping, and including an end cover member 10, a central brush housing member 11 and an opposing end cover member 12, each having a flat planar portion configuration so that when the pieces are assembled they define a flat planar portion on the switch as illustrated in the drawings.

The end cover member 10 is provided with a circular upstanding rib 13 which is adapted to be received in a mating hollow recess 14, shown in FIG. 4, of the central housing member 11, and with a plurality of indentations 15 along the interior of the bottom edge thereof for receiving corresponding projecting tabs 16 of the central housing member 11, also shown in FIG. 4, during assembly of the central housing member 11 onto the end cover member 10. A central recess 17 is also provided in the end cover member 10 for receiving a disc member 18 preferably constructed of a plastic material, the purpose of which will be described later. As shown in FIG. 1, the disc member 18 is formed with a central opening 19 having a square cross-sectional configuration.

A flat circular printed circuit board member 20 having a coded circuit etched on one face thereof is positioned in the recess in the end cover member 10 defined by the upstanding rim 13 thereof. The printed circuit board 20 also is provided with a central throughopening of a square-shaped configuration.

In assembling the switch, the central housing member 11 next is positioned on the end cover member 10 with the tabs 16 thereof being inserted into the indentations 15 as previously described. The rim 13 registers within recess 14. As shown in FIG. 4, the end cover 10 includes an annular rim 21 radially spaced of the rim 13 against which the circuit board 20 abuts. The housing member 11 includes an annular rim 21 which is similar to and in opposing relationship to the rim 21 when the cover 10 and housing member are assembled. The

rims

21 and 21 cooperate to abut and retain the circuit board 20 therebetween, and to prevent warpage of the circuit board. The

rims

21 and 21 are also relatively thin so as to provide bearing surfaces of relatively small areas upon which the circuit board is supported for relatively low friction slidable rotation. The yet open end of the central housing member 11 also is provided with an upstanding rib member 22 which is adapted to be received in a mating recess in the opposing end cover 12 whenassembled. In addition, a central diametrical opening 23 is provided in the central housing member 11 for permitting access of brush contact members 24 to the printed circuit board 20. As illustrated in FIG. 1, the brush members 24 are formed as curved portions on the ends of carrier strip tabs 25 of a special configuration, being elongate in nature and having a right-bend 26 formed therein intermediate the length thereof and a wire-receiving piece 27 at the other end. To accommodate the carrier strip tabs 25, the central brush housing member 11 has a plurality of parallel grooves 28 formed therein, each having a block 29 which is adapted to fit within the bend 26 of a carrier strip tab being received in the groove. Thus, when the carrier strip tabs 25 are placed into the grooves 28, the bends 26 are placed over the blocks 29 so that the curved brushes 24 lie in contact with the printed circuit board 20 and the wire-receiving pieces 27 protrude through the flat planar portion of the switch.

Next, a control shaft 30 having an axial squareshaped opening in one end thereof for receiving a rod 31 of square cross-section is projected through a central opening in the end cover member 12. On the interior surface of the end cover member 12, a recess 32 is formed, as shown in FIG. 2, the periphery of which is somewhat tooth-shaped to provide a plurality of detents 33 for engagement by a gear member 34. The gear member 34 is a substantially ring-shaped piece having a diametrical arm 35 in which a squareconfigured central opening 36 is provided, and a pair of diametrically opposed projecting tabs 37 on the outer periphery thereof which are receivable in the detents 33 and are compressible to such an extent to permit being snapped from one set of detents to an adjacent set of detents upon rotation of the gear member 34. Thus, the detent control 33 and the housing mem ber 12 are of one piece construction for compactness and for elimination of a plurality of separate parts to simplify assembly.

The end cover members 12 having the gear member 34 disposed in the recess 32 thereof fits onto the central brush housing member 11, with the projecting circular rib 22 of the central member 11 being received in an annular groove 38 formed about the detentedrecess 32 of outer end cover member 12. When positioned together in this manner, the square-configured rod 31 projects loosely through the opening 23 in the central brush housing member 11, and tightly fits within the corresponding square-configured openings in the printed circuit board 20 and the disc member 18, so that any rotation imparted to the control shaft 30 is operable to cause rotation of the printed circuit board 20 therewith. The shaft 30 thus provides an axis of rotation about which the printed circuit board 20 is rotatably displaceable. Simultaneously, of course, the gear 34 is rotated when a sufficient turning force is provided for snapping the projecting tabs 37 between adjacent sets of detents 33.

A plurality of projecting tabs 39 formed on the interior surface of the opposing end cover member 12 along the bottom edge thereof are adapted to fit within the lower part of grooves 28 in the central brush housing member 11, below the blocks 29 therein, when the cover members are assembled. An upper set of aper- .

tures

40, 40 and 40 are respectively provided in the

housing members

10, 11 and 12, as are lower sets of

apertures

41, 41', 41" and 42, 42 and 42", for the purpose of securing the housing members together by suitable means, such as bolt and nut connection. In this manner, when so assembled, it may be seen that a dust- .proof housing for enclosing the switch contact elements is provided.

Turning to FIG. 4, wherein the assembled switch is illustrated being mounted on one side of a panel 43 with the control shaft 30 thereof projecting through the panel, a nut 44 is shown being threaded onto an externally threaded central projection 45 of the housing end cover 12 for clamping the switch housing to the panel 43. An O-ring sealing means 46 is shown surrounding the threaded portion 45 on one side of the panel 43 and a suitable sealing washer 47 is provided on the other side between the panel 43 and the securing nut 44. Disposed on the end of the control shaft 30 is a control knob 48 having a suitably shaped recess for receiving the end of shaft 30 which, as shown in FIG. 1, has an arcuate portion thereof cut away, so that rotation of the control knob 48 with a sufficient force will rotate the control shaft 30 and cause gear member 34 to move between distinct rotational positions defined by the detents 33 and the projecting tabs 37, the relationship of which is most clearly shown in FIG. 5.

In certain cases, it may be desirable to provide a switch of the character described which is, for example,

limited to a number of preselected positions, and in such cases another embodiment of the housing end cover 12, as shown in FIGS. 3 and 6 may be provided. The only distinction between this embodiment and that previously described is that stop members 50 are integrally formed on the interior surface of the housing end cover member 12 on the base of the recess 32 therein. Thus, when the control shaft 31 is rotated through operation of the control knob 48, the gear member 34 is caused to turn and is limited in its degree of rotation by the diametrical arm 35 coming into contact with one or the other of stop members 50. As shown, rotation through approximately 180 is possible, since one-half of the diametrical arm 35 is formed being of reduced thickness, or cut away on the surface thereof facing the interior. of the end cover 12 such that it is capable of passing freely over the stop members 50, while only the other portion of the arm 35-serves to preclude further rotation. It should be understood, therefore, where it is desirable to permit nearly complete revolution but to prevent passage through a predetermined zeroposition, only a single stop 50 need be provided in the end cover 12.

The compact construction provided with the present invention readily permits stacking of a plurality of the housings formed by the

housing members

10, 11 and 12 in end-to-end relation, such as illustrated in FIG. 7, in which case if a different code were provided on each isters in the recess 14 of an adjacent stacked housing member 11 without a need for any end cover or front cover 12 therebetween. Thus the rim 22 and the rim 13 are of similar configuration for registration in a recess 14 of any housing member 11. Also, the housing member 11 is provided with a relatively thin annular rim 21" similar to the rim 21 on the end cover 10, so that when an end cover 10 is eliminated between two stacked housing members 11, the rim 21" of one housing member 11 will cooperate with the rim 2] of the other stacked housing member to slidably support a circuit board 20 in the same manner as the board 20 is supported by the

rims

21 and 21 as shown in FIG. 4. Thus, between stacked housing members 11, the cover 10 can be eliminated, with an adjacent housing member 11 performing the functions of the cover plate 10. This results in a compact assembly with the control shaft 31 being supported only at its ends, by one end cover 10 at one end, and by one housing member 12 at the other end. With only one housing member 12 required, only one detent control 33 is needed for an entire assembly of stacked circuit boards 20.

Turning now to FIGS. 8 and 9, there are shown different methods of electrically connecting the brushes 24 exteriorally of the housing which may be employed with the compact and unique construction of the present invention. In FIG. 8, for example, an electrical wire may be bent in a conventional manner and inserted into the wire-receiving piece 27 of the carrier strip tabs 25, which then is compressed thereabout. In FIG- 9, however, the wire-receiving pieces 27 are shown being bent back for receiving terminal posts, such that a plug-in adaptation would be possible. It is noted, in this respect, that the inputs and outputs, or all of the carrier strip tabs 25, are positioned inone plane to facilitate plugging the same into a printed circuit board.

Another embodiment of the present invention is illustrated in FIGS. 10 and 11, wherein a decimal version is provided. In this embodiment, a housing member 51 provides a recess 52 for receiving a printed circuit board 53, with a tab 54 projecting from the recess 52 being engaged with an aperture 55 in the printed circuit board. A thin disc-like piece 56 having a central square-configured opening and a plurality of pins projecting from one face thereof is fixed to one face of the printed circuit board 53 with the pins thereof extending through a central opening 57 in the board being received in corresponding pin openings in a thin washer element 58 on the printed circuit side of the board 53. A ring brush member 60 is engaged between the washer member 58 and a plug 61 havingv a central post extending through an opening of the brush ring 60 and a base member having pin openings therein for receiving the pins of the disc member 56 and extending through the washer member 58. The base and post portions of the plug member 61 are provided with a continuous through opening of square configuration for receiving a control shaft 31 of the type described hereinbefore. The brush ring 60 accordingly is rotatably fixed on the printed circuit board 53.

Referring more particularly to FIG. 11, the brush ring 60 is shown having

arcuate arms

62 and 63 extending in opposite circumferential directions which are bent in the direction of the printed circuit board so that the ends thereof engage the board. The one arm 62 is at a lesser radial distance from the brush ring center than the other arm 63, such that it is always in engagement with an annular conductive area 64 on the board 53 positioned about the central opening 57 therein. The other arm 63 is adapted upon rotation of the brush ring 60 to engage a different one of a plurality of conductive areas 65 on the printed circuit board, whereby different circuits may be connected according to the rotating of the control shaft to preselected different rotary positions.

With this embodiment, an end cover, not shown, must be provided on the side of the housing member 51 opposite the printed circuit board 53, and another end cover 66 having the same detent and internal gear arrangement as described above must be provided for the printed circuit board side of the housing member 51. These end covers must of course be different than the end covers 10 and 12 above, especially along the bottom edges thereof, so that they conform to the housing member 51 to provide a dust-proof enclosure. Obviously, the outputs of the printed circuit board 53 may be made for plugging the same into a printed circuit board or they could be provided with spaced tabs for breaking conventional wire connections.

With the embodiments described hereinabove, it should be clear that the objects of this invention have been achieved. Further, in order to vary the code of any of the switches described herein, it is only necessary to change the printed circuit board, which may be accomplished at the time of manufacture. The number of detent positions is determined by the code, or the design of the conductive area of the printed circuit board. Because of the plastic material used in manufacturing the parts, the switch is less susceptible to damage, and its novel arrangement of elements makes the switch more adaptable to various applications, while at the same time being very compact.

Obviously, many modifications and variations are possible in light of the above teachings. It is to be understood, therefore, that within the scope of the appended claims the invention may be practiced otherwise than is specifically described herein.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In a switch having a housing, a printed circuit board mounted for displacement in said housing, at least one electrical contact protruding ,extemally of said housing and having a brush portion protruding into said housing and engaging said printed circuit board for electrical engagement on a selected electrical circuit provided on said printed circuit board upon displacement of said printed circuit board, and means mounted in said housing for displacing said printed circuit board, the improvement comprising: a pair of bearing surfaces fixedly located on said housing and abutting and supporting opposite sides of said printed circuit board and retaining said circuit board therebetween and preventing warping of said printed circuit board.

2. The structure as recited in claim 1, wherein said printed circuit board is displaceable about, an axis of rotation, said bearing surfaces are circular rims, said rims encircle and axis of rotation of said printed circuit board, and said rims abut and support said printed circuit board circularly about its axis ofrotation to prevent warping of said printed circuit board.

3. The structure as recited in claim 2, wherein, said rims are relatively thin to provide bearing surfaces of relatively small areas upon which the printed circuit board is slidably supported for relatively low sliding friction.

4. The structure as recited in claim 1, and further including: at least one additional electrical contact protruding externally of said housing and having a brush portion protruding internally into said housing and engaging said printed circuit board for selective electrical engagement with a selected electrical circuit provided on said printed circuit board.

5. The structure as recited in claim 4, wherein, said housing has a flat planar portion, and all of said electrical contacts protrude from said housing only through said flat planar portion for making electrical connections externally of said housing.

6. The structure as recited in claim 4, wherein, said housing includes an internal detent portion, and further including: a gear mounted in said housing for selective engagement in said detent portion, thereby positively locating said printed circuit board in selected positions determined by selective engagement of said gear in said detent portion.

7. The structure as recited in claim 1, wherein, said housing includes detent means, and further including: a gear mounted in said housing for displacement and having a portion displaceable into selected engagement in said detent means, thereby positively locating said printed circuit board in a selected positions defined by the selected engagement of said gear in said detent means.

8. The structure as recited in claim 4, wherein, said electrical contacts include electrical wire-receiving portions protruding externally of said housing for making electrical connections externally of said housing.

9. The structure as recited in claim 4, wherein, said housing includes a first member having grooves each receiving one of said electrical contactstherein, said grooves each having a shape conforming to the shape of a corresponding electrical contact for registration of the corresponding electrical contact fixedly in position within the groove, and a cover overlying said first member with said electrical contacts interposed between said first member and said cover, whereby said electrical contacts are fixedly retained with respect to said housing.

10. A switch, comprising: a first brush housing mem-' ber of electrical insulation material having aplurality of electrical contacts mounted thereon, said contacts further having electrical terminal portions protruding externally of said brush housing member formaking desired electrical connections externally of said brush housing member, a first printed circuit board having electrical circuits thereon, said contacts having brush portions protruding internally of said brush housing member and engaging said printed circuit board, a first cover portion engaging and covering one end of said brush housing member, said first printed circuit board being enclosed by and interposed between said first cover portion and said brush housing member, said first cover portion including a support means engaging said printed circuit board, said brush housing member 'having a first bearing surface engaging said printed circuit board and cooperating with said support means to support said printed circuit board therebetween and thereby prevent warpage of said printed circuit board, covering means covering another end of said brush housing member, and displacing means mounted on said switch for displacing said first printed circuit board relative to said brush portions for engagement of said brush portions with selected electrical circuits on said first printed circuit board, said first printed circuit board being slidably displaceable relative to said support means and said first bearing surface.

11. The structure as recited in claim 10, wherein, said covering means includes a second brush housing member abutting said first brush housing member, a second printed circuit board interposed between said first and said second brush housing members, said second printed circuit board being provided with electrically conducting circuit paths thereon, electrical contact means in said second brush housing member, said second printed circuit board being displaceable relative to said electrical contact means to enable selected electrical engagement of said electrical contact means with selected electrically conducting circuit paths on said second printed circuit board, said first brush housing member having a second bearing surface engaging said second printed circuit board, said second brush housing member having bearing surface means engaging said second printed circuit board and cooperating with said second bearing surface of said first brush housing member to support therebetween said second printed circuit board and to prevent warpage of said second printed circuit board, said second printed circuit board being slidably displaceable by said displacing means relative to said second bearing surface and said bearing surface means.

12. The structure as recited in claim 10, wherein, said first printed circuit board is rotatably displaceable about an axis of rotation, said first bearing surface is in the form of a circularrim encircling said axis of rotation, and said rim is of relatively thin configuration to minimize the bearing surface area thereof engaging said first printed circuit board and to minimize sliding friction resulting from displacement of said first printed 'circuit board relative to' said rim.

13. The structure as recited in claim 10, wherein, said first printed I circuit board is rotatably displaceable about an axis of rotation, said support means is in the form of a circular rim encircling said axis of rotation, and said rim is of relatively thin configuration to minimize the bearing surface area thereof engaging said first printed circuit board and to minimize the sliding friction resulting from displacement of said first printed circuit board relative to said rim.

14. The structure as recited in claim 10, wherein, said first printed circuit board is rotatably displaceable about an axis of rotation, and said support means and said first bearing surface are in the respective forms of circular rims encircling the axis of rotation of said first printed circuit board, said circular rims being of relatively thin configurations to minimize the bearing surface areas engaging said first printed circuit board and to minimize sliding friction resulting from displacement of said first printed circuit board relative to said rims.

15. The structure as recited in claim 10, wherein, said brush housing member is provided with grooves each receiving one of said electrical contacts therein, each of said grooves having a shape corresponding to the shape of a corresponding electrical contact for registration of the corresponding electrical contact fixedly in position within the groove, said electrical contacts being interposed between said brush housing member and said covering means, whereby said electrical contacts are fixedly retained with respect to said brush housing member.

16. The structure as recited in claim 1 1, wherein, said first printed circuit board is rotatably displaceable about an axis of rotation, and said support means and said first bearing surface are in the respective forms of circular rims encircling the axis of rotation of said first printed circuit board, and said circular rims are of relatively thin configurations to minimize the bearing surface areas engaging said first printed circuit board and to minimize the sliding friction resulting from displacement of said first printed, circuit board relative to said rims.

17. The structure as recited in claim 1 1, wherein, said first printed circuit board is rotatably displaceable about an axis of rotation, said support means is in the form of a circular rim encircling said axis of rotation, and said rim is of relatively thin configuration to minimize the bearing surface area thereof engaging said first printed circuit board and to minimize the sliding friction resulting from displacement of said first printed circuit-board relative to said rim.

18. The structure as recited in claim 1 1, wherein, said first printed circuit board is rotatably displaceable about an axis of rotation, said first bearing surface is in the form of a circular rim encircling said axis of rotation, and said rim is of relatively thin configuration to minimize the bearing surface area thereof engaging said first printed circuit board and to minimize the sliding friction resulting from displacement of said first printed circuit board relative to said rim.

19. The structure as recited in claim 1 1, wherein, said switch is provided with detent means, and said displacing means is provided with a gear displaceable into selected engagement within said detent means for locating said first and said second printed circuit boards in selected positions defined by the selected engagement of said gear within said detent means.

20. The structure as recited in claim 19, wherein, said switch includes a projecting stop member, and said gear member is engageable against said stop member to limit displacement of said gear member.

21. The structure as recited in claim 11, wherein, said first brush housing member includes a plurality of grooves each receiving one of said electrical contacts therein, said grooves each having a shape conforming to the shape of a corresponding electrical contact for registration of the corresponding electrical contact fixedly in position within the groove, and said covering means overlying said first brush housing member with said electrical contacts generally interposed between said first brush housing member and said covering means whereby said electrical contacts are fixedly retained with respect to said first brush housing member.

22. The structure as recited in claim 1 1, wherein, said brush housing member, said first cover portion and said covering means define on said switch a planar portion, and said electrical contacts and said electrical contact means protrude from said planar portion formaking electrical connections externally of said switch.

23. The structure as recited in claim 1 1, wherein, said second brush housing member includes a plurality of grooves receiving said electrical contact means therein, said grooves having shapes conforming to the shapes of said electrical contact means for registration of the electrical contact means fixedly in positions within the grooves, and 'means overlying said second brush housing member with said electrical contact means generally interposed between said second brush housing member and said lastmentioned means, whereby said electrical contact means are fixedly retained with respect to said second brush housing member.

24. The structure as recited in claim 4, wherein, said electrical contacts include pluggable portions for pluggable connection externally of said rotary switch.

25. A rotary switch comprising: a housing; a printed circuit board; at least one electrically conducting brush means; means for supporting said printed circuit board and said at least one brush means in contacting relation within said housing; means for rotating said printed circuit board to one of a predetermined number of distinct positions; a circular array of detents formed in a plane on an interior surface of said housing; a gear disposed within said circular array of detents in the same plane and having at least one projecting compressible tab for engaging in said detents; means connecting said gear and said printed circuit board for providing simultaneous rotation thereof; means for rotating said gear from outside said housing; and said housing further comprising, one end cover for rotatably receiving said printed circuit board therein, a brush housing member connectable with said one end cover in substantially dust-free relation and having means therein for supporting the brush means with portions thereof extending therefrom in a common plane, another end cover connectable to said brush housing member in substantially dust-free relation, means on said another end cover for connecting said housing on a panel with said means for rotating said printed circuit board projecting through said panel to a side thereof opposite said housing, and sealing means on said another end cover sealing said means for rotating said printed circuit board to provide a substantially dust-free environment in said switch housing.

26. The structure as recited in claim 11, wherein said second printed circuit board is rotatably displaceable about an axis of rotation, said second bearing surface is in the form of a circular rim encircling said axis of rotation, and said rim is of relatively thin configuration to minimize the bearing surface area thereof engaging said second printed circuit board and to minimize the sliding friction resulting from displacement of said second printed circuit board relative to said rim.

27. The structure as recited in claim 11, wherein said second printed circuit board is rotatably displaceable about an axis of rotation, said bearing surface means is in the form of a circular rim encircling said axis of rotation, and said rim is of relatively thin configuration to minimize the bearing surface area thereof engaging said second printed circuit board and to minimize the sliding friction resulting from displacement of said second printed circuit board relative to said rim.

28. The structure as recited in claim 11, wherein said second printed circuit board is rotatably displaceable about an axis of rotation, said bearing surface means and said second bearing surface are in the respective forms of circular rims encircling said axis of rotation, and said rims are of relatively thin configurations to minimize the bearing surface areas thereof engaging said second printed circuit board and to minimize the sliding friction resulting from displacement of said second printed circuit board relative to said rims.

29. The structure as recited in claim 10, wherein said brush housing member, said first cover portion and said covering means define a flat planar portion of said switch, said electrical contacts protrude from said flat planar portion for making electrical connections externally of said switch.

30. The structure as recited in claim 25, wherein said switch further includes at least another brush housing member interposed between said another end cover and said means for supporting said printed circuit board, a printed circuit means in said another brush housing member, electrical contact means in said another brush housing member having brush means contacting said printed circuit means, and said printed circuit means being rotatable together with said printed circuit board by said means for rotating said printed circuit board to one of a predetermined number of positions.

31. The structure as recited in claim 30, wherein said first-mentioned brush housing member includes a first bearing surface abutting and slidably supporting said printed circuit board, said first-mentioned brush housing member includes a second bearing surface slidably abutting and supporting said printed circuit means, and said another brush housing member includes a third bearing surface slidably supporting said printed circuit means.

32. The structure as recited in claim 30, and further including additional electrically conducting brush means mounted in said another brush housing member and in contact with said printed circuit means.

Claims

1. In a switch having a housing, a printed circuit board mounted for displacement in said housing, at least one electrical contact protruding externally of said housing and having a brush portion protruding into said housing and engaging said printed circuit board for electrical engagement on a selected electrical circuit provided on said printed circuit board upon displacement of said printed circuit board, and means mounted in said housing for displacing said printed circuit board, the improvement comprising: a pair of bearing surfaces fixedly located on said housing and abutting and supporting opposite sides of said printed circuit board and retaining said circuit board therebetween and preventing warping of said printed circuit board.

2. The structure as recited in claim 1, wherein said printed circuit board is displaceable about an axis of rotation, said bearing surfaces are circular rims, said rims encircle and axis of rotation of said printed circuit board, and said rims abut and support said printed circuit board circularly about its axis of rotation to prevent warping of said printed circuit board.

9. The structure as recited in claim 4, wherein, said housing includes a first member having grooves each receiving one of said electrical contacts therein, said grooves each having a shape conforming to the shape of a corresponding electrical contact for registration of the corresponding electrical contact fixedly in position within the groove, and a cover overlying said first member with said electrical contacts interposed between said first member and said cover, whereby said electrical contacts are fixedly retained with respect to said housing.

10. A switch, comprising: a first brush housing member of electrical insulation material having a plurality of electrical contacts mounted thereon, said contacts further having electrical terminal portions protruding externally of said brush housing member for making desired electrical connections externally of said brush housing member, a first printed circuit board having electrical circuits thereon, Said contacts having brush portions protruding internally of said brush housing member and engaging said printed circuit board, a first cover portion engaging and covering one end of said brush housing member, said first printed circuit board being enclosed by and interposed between said first cover portion and said brush housing member, said first cover portion including a support means engaging said printed circuit board, said brush housing member having a first bearing surface engaging said printed circuit board and cooperating with said support means to support said printed circuit board therebetween and thereby prevent warpage of said printed circuit board, covering means covering another end of said brush housing member, and displacing means mounted on said switch for displacing said first printed circuit board relative to said brush portions for engagement of said brush portions with selected electrical circuits on said first printed circuit board, said first printed circuit board being slidably displaceable relative to said support means and said first bearing surface.

12. The structure as recited in claim 10, wherein, said first printed circuit board is rotatably displaceable about an axis of rotation, said first bearing surface is in the form of a circular rim encircling said axis of rotation, and said rim is of relatively thin configuration to minimize the bearing surface area thereof engaging said first printed circuit board and to minimize sliding friction resulting from displacement of said first printed circuit board relative to said rim.

13. The structure as recited in claim 10, wherein, said first printed circuit board is rotatably displaceable about an axis of rotation, said support means is in the form of a circular rim encircling said axis of rotation, and said rim is of relatively thin configuration to minimize the bearing surface area thereof engaging said first printed circuit board and to minimize the sliding friction resulting from displacement of said first printed circuit board relative to said rim.

16. The structure as recited in claim 11, wherein, said first printed circuit board is rotatably displaceable about an axis of rotation, and said support means and said first bearing surface are in the respective forms of circular rims encircling the axis of rotation of said first printed circuit board, and said circular rims are of relatively thin configurations to minimize the bearing surface areas engaging said first printed circuit board and to minimize the sliding friction resulting from displacement of said first printed circuit board relative to said rims.

17. The structure as recited in claim 11, wherein, said first printed circuit board is rotatably displaceable about an axis of rotation, said support means is in the form of a circular rim encircling said axis of rotation, and said rim is of relatively thin configuration to minimize the bearing surface area thereof engaging said first printed circuit board and to minimize the sliding friction resulting from displacement of said first printed circuit board relative to said rim.

18. The structure as recited in claim 11, wherein, said first printed circuit board is rotatably displaceable about an axis of rotation, said first bearing surface is in the form of a circular rim encircling said axis of rotation, and said rim is of relatively thin configuration to minimize the bearing surface area thereof engaging said first printed circuit board and to minimize the sliding friction resulting from displacement of said first printed circuit board relative to said rim.

19. The structure as recited in claim 11, wherein, said switch is provided with detent means, and said displacing means is provided with a gear displaceable into selected engagement within said detent means for locating said first and said second printed circuit boards in selected positions defined by the selected engagement of said gear within said detent means.

22. The structure as recited in claim 11, wherein, said brush housing member, said first cover portion and said covering means define on said switch a planar portion, and said electrical contacts and said electrical contact means protrude from said planar portion for making electrical connections externally of said switch.

23. The structure as recited in claim 11, wherein, said second brush housing member includes a plurality of grooves receiving said electrical contact means therein, said grooves having shapes conforming to the shapes of said electrical contact means for registration of the electrical contact means fixedly in positions within the grooves, and means overlying said second brush housing member with said electrical contact means generally interposed between said second brush housing member and said lastmentioned means, whereby said electrical contact means Are fixedly retained with respect to said second brush housing member.