US3621162A

US3621162A - Rotatable switch for providing electrical pulses and indicating the direction of switch rotation

Info

Publication number: US3621162A
Application number: US24276A
Authority: US
Inventors: Robert F Wall
Original assignee: Monsanto Co
Current assignee: Monsanto Co
Priority date: 1970-03-31
Filing date: 1970-03-31
Publication date: 1971-11-16
Anticipated expiration: 1988-11-16

Abstract

A rotatable switch having a printed circuit part including a plurality of conductive elements connected to terminals, which in turn may be connected to sources of operating potential. Two of the conductive elements cooperate with contacts of a rotatable switch part to produce electrical pulses, while other conductive elements of the printed circuit part cooperate with a switch contact of the rotatable switch part to sense and indicate the direction of switch rotation.

Description

0 United States Patent 1 3,621,162

[72] Inventor Robert F. Wall 3,409,747 1 l/l968 Mincone 200/1 1 TW ChesterfieMMo- I OTHER REFERENCES 323 1970 IBM Disclosure Bulletin, Station Selector Device," oy Wolfhermer, Vol. 9, No. 8, page 975 Jan. 1967 (Copy in [45] Paemed 1971 Scientific Library) 200 l [73] Assignee Monsanto Company St. Louis, Mo. Primary ExaminerRobert K. Schaefer Assistant Examiner-M. Ginsburg Attorneys-John D. Upham, Herman O. Bauermeister and [54] ROTATABLE SWITCH FOR PROVIDING Harold R. Patton ELECTRICAL PULSES AND INDICATING THE DIRECTION OF SWITCH ROTATION 5 Claims, 16 Drawing Figs.

[52] US. Cl 200/6139,

200/] 1 D ABSTRACT: A rotatable switch having a printed circuit part [5 l] Int. Cl H0lh 3/16 including a p|um|ity f conductive elements connected to [50] Field of Search ZOO/61.39, minds, which in mm may be connected to Sources f Open". 1 ing potential. Two of the conductive elements cooperate with contacts of a rotatable switch part to produce electrical pul- [56] References Cited ses, while other conductive elements of the printed circuit part UNITED STATES PATENTS cooperate with a switch contact of the rotatable switch part to 2,147,630 2/l939 Metcalf 200/6l.39 X sense and indicate the direction of switch rotation.

PATENTEUR V 16 Ian SHEEI 1 [IF 3 ATTORNEY PATENTEnuuv 16197! 3,621 162 sum 2 0r 3 INVENTOR ROBERT F. WALL ATTORNEY PATENTEnunv 16 Ian SHEET 3 [IF 3 INVENTOR ROBERT ALL ATTORNEY ROTATABLE SWITCH FOR PROVIDING ELECTRICAL PULSES AND INDICATING THE DIRECTION OF SWITCH ROTATION FIELD OF THE INVENTION The present invention relates generally to an electrical switch, and more particularly, to a rotatable switch for producing electrical pulses at a rate proportional to the speed of rotation and, in addition, indicate the direction of rotation of the switch.

BACKGROUND OF THE INVENTION In the field dealing with the control of certain industrial processes (for example, those employed in a modern automated chemical plant), electronic controllers are often employed to monitor, display and vary control parameters associated with the particular processes. Such an electronic controller and its attendant circuitry is described in U.S. Pat. application Ser. No. 729,738,253 filed June 25, I968 entitled Analog Controller Including Manual Pulse-Train Control" by V. A. Lauher and L. H. Fricke, Jr. and assigned to the assignee hereof, now U.S. Pat. No. 3,566,282. The aboveidentified patent application describes an electronic controller in which a manually operable switch is employed in combination with novel circuitry to generate a pulse train having a frequency determined by an operator, who rotates the switch in either of two directions to produce the pulses. The switch employed for generating the pulses is also used to determine the polarity (positive or negative) of the pulses depending upon the direction of rotation selected by the operator.

SUMMARY OF THE INVENTION The general purpose of this invention is to provide a rotatable switch which embraces all of the advantages of similar rotatable switches, yet serves the dual function of generating a plurality of pulses at a selected rate and indicating the direction of rotation. In addition, the rotatable switch of the present invention is extremely compact, yet inexpensive to manufacture and assemble. To attain the purposes mentioned, the present invention utilizes the combination of a unique printed circuit switch part together with, a wheel part rotatably mounted to the printed circuit part and carrying contacts which cooperate with conductive elements of the printed circuit part to generate pulses proportional to the rate of rotation of the rotatable wheel part and, in addition, indicate the direction of rotation of the wheel part.

An object of the present invention is the provision of a rotatable switch which provides electrical pulses at a rate proportional to its rate of rotation and further provides an indication of the direction of rotation.

Another object of the present invention is to provide a rotatable, wheel-type, pulse generating switch of compact construction, but which is inexpensive to manufacture and assemble, and relatively maintenance free.

In the present invention these purposes (as well as others apparent herein) are achieved generally by employing a printed circuit card part having deposited thereon a plurality of electrically conductive films or segments spaced-apart so as to be electrically isolated from each other. Each of the conductive segments are provided with contact terminals, by which they may be connected to external circuits. The printed circuit card is further provided with an abutment or stop ele ment which projects from the surface to which the conductive films are deposited. A nonconductive, wheel part is rotatably mounted to the printed circuit card and carries a plurality of contacts arranged in a predetermined relationship so as to register with respective conductive film segments of the printed circuit card part. Rotation of the wheel part allows one set of contacts to passover certain conductive film segments, thereby to undergo make-and-break" switch action and produce electrical pulses in a commutator fashion. Another contact carried by the wheel part is caused to rotate between two predetermined positions, depending upon the direction of rotation of the wheel, and make or break with a printed circuit card part contact, thereby to indicate the direction of rotation.

BRIEF DESCRIPTION OF THE DRAWINGS Utilization of the present invention become apparent to those skilled in the art from the disclosures made in the following description, as illustrated in the accompanying drawings; in which FIG. 1 is a view of the interior surface of the pulse wheel part of the rotatable switch of the present invention;

FIG. 2 is a cross-sectional view of the pulse wheel part of FIG. 1 taken along line 22 thereof;

FIG. 3 is a partial, cross-sectional view of the pulse wheel part of FIG. 1 taken along line 33 thereof;

FIG. 4 is a plan view of the pulse wiper part of the rotatable switch of the present invention;

FIGS. 5 and 6 are cross-sectional views taken along lines 55 and 66, respectively, of FIG. 4;

FIG. 7 is a plan view of the switch wiper part of the rotatable switch of the present invention;

FIG. 8 is a cross-sectional view of the switch wiper part of FIG. 7 taken along line 8-8 thereof;

FIG. 9 is a plan view of the spring washer part of the rotatable switch of the present invention;

FIG. 10 is a side view of the spring washer part of FIG. 9;

FIG. 11 is a plan view of the printed circuit board part of the rotatable switch of the present invention;

FIG. 12 is a cross-sectional view of the printed circuit board part of FIG. 1] taken along line 12-12 thereof;

FIG. 13 is a front view of the pulse wheel retainer part of the rotatable switch of the present invention;

FIG. 14 is a cross-sectional view of the pulse wheel retainer part of FIG. 13 taken along line 14-14 thereof, and

FIG. 15 is a view of the assembled, rotatable switch of the present invention mounted to a housing and having various parts broken-away to reveal the internal arrangement of switch parts; and

FIG. 16 is a cross-sectional view of the assembled, rotatable switch of FIG. 15 taken along line l6-l6 thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 15 a rotatable switch, generally designated 10, mounted to an appropriate housing, such as an instrument casing, and having insulated wires 0, b, c, and d leading therefrom to external circuitry or electrical apparatus (not shown). The rotatable switch 10 includes a pulse wheel part 12, a pulse wiper part 14, a switch wiper part 16, a spring washer part 18, a printed circuit board part 20, a pulse wheel retainer part 22, and a retainer washer 24. These various rotatable switch parts will now be described with reference to FIGS. 1-14.

The pulse wheel part 12 is shown in detail in FIGS. I and 2. It is preferably a molded-plastic part, generally circular in overall shape and having an outer rim 26 which is knurled to facilitate engagement during rotation. The pulse wheel part I2 is provided with a stepped or raised central hub-portion 28, the first step 30 of which serves to receive the switch wiper part 16 and space it from the pulse wiper part 14 which is received and retained against the flat surface portion 32 between the hub portion and the outer rim 26. The second step 34 of the raised, central hub 28 is offset fromthe first step 30 and slots 36 therein serve to receive the spring washer part 18 and space it from the pulse wiper part 14, so that direct electrically contact between these parts is prevented. However, as will be more fully described hereinafter, the spring washer part I8 is bent, in assembly, to contact the switch wiper part 16. The slots 36 of the raised central hub 28 consist of four radial slots fonned within the upper, second step 34 and spaced at intervals from each other. A circular aperture 38 extends through the raised central hub 28 and communicates with a generally circular recess 40 adapted to receive a portion of the pulse wheel retainer part 22. The flat surface portion 32 of the pulse wheel part 12 is provided with four small, raised projections 42, see particularly FIG. 3. Radially outward of the raised projections 42, the pulse wheel part 12 is provided with a retainer lip 44 adapted to receive and provide a close fit to the printed circuit board part 20 when the pulse wheel part 12 is rotatably mounted thereto in the manner to be more fully described hereinafter. As will be apparent, the printed circuit board part 20 fits within the lip 44 and abuts against the surface 46 of the pulse wheel part I2. This fitting arrangement positions the printed circuit board part relative to the various switch parts carried by the pulse wheel part 12.

Referring now to FIGS. 4, 5, and 6, there is shown the pulse wiper part 14 of the rotatable switch 12. The pulse wiper part 14 is preferably a flat, stamped-metal part fabricated from a conductive, resilient metal, such as a berillium-copper alloy. The pulse wiper part 14 is generally annular in shape having

cutaway portions

46 and 48 diametrically opposed to each other to form

spring leaf portions

50 and 52, as may be best seen in FIGS. and 6. The

spring leafs

50 and 52 are bent to extend upwardly from the remainder of the spring wiper part 14 to terminate in

flat portions

54 and 56, respectively. The

flat portions

54 and 56 of the

spring leafs

50 and 52 are provided with

conductive contacts

58 and 60, which preferably take the form of rivets secured to the leafs. The inner and outer diameters of the pulse wiper part 14 are chosen such that it fits within the pulse wheel part 12 against the flat portion 32 intermediate its outer rim 26 and its raised central hub 28. Four apertures or holes 62 are provided at spaced intervals in the pulse wiper part 14. These apertures 62 are spaced such that they register with and fit over the four projections 42 of the pulse wheel part 12.

The switch wiper part 16 of the rotatable wheel part 12 is shown in detail in FIGS. 7 and 8. Like the pulse wiper part 14, the switch wiper part 16 is preferably a resilient conductive metal part stamped from a sheet of berillium-copper alloy. It too is generally annular in overall configuration and has a circular aperture 64 whose diameter is chosen so that it fits upon the first step 30 of the raised central hub 28 of the pulse wheel part 12. The switch wiper part 16 has a cutaway portion 66 which serves to form a spring leaf 68 similar to the

spring leafs

50 and 52 of the pulse wiper part 14. Along its flat portion 70, the spring leaf 68 is provided with a contact rivet 72. It should be noted that the flat portion 70 of the switch wiper part 16 terminates at an opening 74, which may be best seen in FIG. 7. As will become more apparent hereinafter, this opening 74 is essential to the proper operation of the switch wiper part 16. It cooperates with the printed circuit board part to insure switch action corresponding to the direction of rotation of the pulse wheel part 12.

Referring now to FIGS. 9 and 10, there is shown the spring washer part I8 of the rotatable switch 10. It is generally annular in overall configuration, but as may be best seen in FIG. 10, the spring washer part 18 is warped or bent into a general C" shape. The spring washer part 18 has four teeth 76 which project inwardly and have a width such that each may be fitted within the slots 36 provided in the second step 34 of the raised central hub 28 of the pulse wheel part 12. Like the pulse wiper part 14 and the switch wiper part 16, the spring washer part 18 is preferably a conductible resilient metal stamped from a sheet ofa berillium-copper alloy.

Referring now to FIGS. 11 and 12, there is shown the printed circuit board part 20 of the rotatable switch 10. The printed circuit board part 20 includes an insulator base portion 78, such as a glass-epoxy combination (or any other suitable insulator upon which a conductive metal film may be deposited). The printed circuit board part 20 is provided with a central aperture 80 which extends from the outer surface 82, to its inner surface 84. Along its outer surface 82, the aperture 80 is flared for purposes to be described hereinafter. The inner surface 84 of the printed circuit board part 20 has deposited thereon conductive metal films or segments, which for example, may be deposited using well-known printed circuit formation techniques. In close proximity to the peripheral edge of the printed circuit board card 20 there are provided a plurality of conductive film segments or fingers 86, which serve as commutator elements for the rotatable switch 10. Each of the fingers are separated from each other by metal film pads 88, which are electrically isolated from the fingers 86. As may be seen from FIG. 11, a conductive innerconnect 90, having a ringlike shape, electrically connects the fingers 86. The innerconnect ring is electrically connected to one terminal 92 of the rotatable switch 10 by means of a connection 94. The terminal 92 is embedded in the base 78 ofthe printed circuit card part 20 and may be connected to one of the wires a, b, c, or a extending through holes provided in the base 78 and leading to external circuitry or apparatus (see FIG. 15). Another conductive metal ring, similar to the innerconnect ring 90, is provided as shown at 96 on the inner surface of the printed circuit board part 20. The conductive metal ring 96 is interrupted as shown in 98 so as to permit the connection 94 to communicate between the terminal 92 and the innerconnect ring 90 without shorting the innerconnect ring 90. The conductive metal ring 96 is connected to a terminal 100 by a connection 101. As will become more apparent hereinafter, the conductive fingers 86 and the conductive metal ring 96 of the printed circuit board part 20 cooperate with contacts of the pulse wiper part 14 to provide electrical pulses in response to rotation of the pulse wheel part 12.

lnwardly of the conductive-metal ring 96 there is provided another conductive-metal ring 102. Intermediate the conductive-metal ring 102 and the conductive-metal ring 96, there are provided two conductive, metal-

film contacts

104 and 106 in close proximity to, but electrically isolated from, each other. The metal film contact 104 is connected by means of an innerconnect 108 to a terminal 110, while the conductivemetal ring 102 is connected to a terminal 112 by means of an innerconnect 114. The contact 106 is electrically floating, or in other words, electrically isolated. An abutment stop or projection 116 is embedded in the base 78 of the part 20 at the contact 106 and extends for a short distance therefrom.

Referring now to FIGS. I3 and 14, there is shown the pulse wheel retainer part 22 of the rotatable switch 10. The pulse wheel retainer part 22 serves to rotatably mount the pulse wheel part 12 of the rotatable switch 10 to the printed circuit board part 20. It includes an outer disclike portion 118, adapted to fit loosely within the recess 40 of the pulse wheel part 12, and a projecting boss portion 120, adapted to fit within the aperture 38 of the hub 28 of the pulse wheel part 12. A thin-walled projection portion 122 of the pulse wheel retainer part 22 extends outwardly from the boss portion 120 and is of a diameter sufficient to fit within the aperture 80 of the printed circuit card part 20. That is, the projection portion 122 is shaped so that it can be swaged outwardly against the flared surface of the aperture 80 of the printed circuit board part 20. V

The pulse retainer part 22 is provided with threaded aperture 124 for purposes to be described hereinafter.

Referring again to FIGS. 15 and 16, the rotatable switch 10 is shown assembled and mounted to an instrument casing 126. In assembling the rotatable switch 10, the pulse wiper part 14 is inserted within the pulse wheel part 12 such that the four projections 42 of the pulse wheel part 12 are inserted within the four apertures 62 of the pulse wiper part 14. The projections 42 are then heated and depressed, for example, by contacting them with a soldering iron or other heating element, and thereby flattened. This secures the pulse wiper part 14 to the pulse wheel part 12 with the contact rivets 58 and 60 extending in the direction of the raised central hub 28. This arrangement may be best seen in FIG. 16. It should be noted that the contact rivets 58 and 60 are radially offset from each other so as to register with the fingers 86 and the ring 96 of the printed circuit card part 20, as will become more apparent hereinafter.

Next, the switch wiper part 16 is inserted over the hub 28 so as to rest on the first step 30 thereof. It should be apparent that the switch wiper part 16 makes frictional engagement with the hub 28 and is free to rotate in any direction with the hub 28. The switch wiper part 16 is inserted on the hub such that its spring leaf 68 and contact rivet 72 extend away from the flat surface 32 of the pulse wheel part 12. The spring washer part 18 is then placed over the hub 28 so as to contact the switch wiper part 16. The switch washer part 18 is positioned on the hub 28 such that its teeth 76 are registered with and fit within the slots 36 thereof. In this position the spring washer part 18 forms a bridging connection between the switch wiper part 16 and the conductive-metal ring 102 of the printed circuit board part 20 when it is inserted within the pulse wheel part 12.

The printed circuit board part 20 is then inserted within the pulse wheel part 12 such that it fits within the recess defined by the lip 40, with its aperture 80 aligned with the aperture 38 of the pulse wheel part 12. In addition, the printed circuit board part 20 is positioned within the recess 40 of the pulse wheel part 12 such that the projection or abutment stop 116 is positioned within the opening 74 of the switch wiper part 16.

As a next assembly step, the washer 24 is inserted over the projection boss portion 120 of the pulse wheel retainer part 22 and the pulse wheel retainer part 22 is inserted within the aperture 38 of the pulse wheel part 12 such that the thin projection 122 extends through the base 78 of the printed circuit board part 20. The thin-walled projection portion 122 of the pulse wheel retainer part 22 is then swaged outwardly against the flared surface of the aperture of the printed circuit board part 20 to securely, but rotatably, mount the pulse wheel part 12. The rotatable switch 10, thus assembled, may then be secured to the instrument housing 126, for example, by means of a screw inserted through the instrument casing 126 and threaded into the threaded portion of the pulse wheel retainer part 22.

The rotatable switch may then be rotated in either the clockwise or counterclockwise direction, as viewed in FIG. 15. When rotated in either the clockwise direction or counterclockwise direction, the

contacts

58 and 60 of the pulse wiper part 14 pass over the fingers 86 and innerconnect ring 96, respectively, of the printed circuit board part 20, thereby providing a make-and-break switch action and provided the terminals 92 and 100 are connected to an electrical circuit including a source of unidirectional potential, a train of electrical pulses are delivered to the circuit at a pulse rate proportional to the speed of switch rotation. It should be apparent to those skilled in the art, that the terminals 92 and 100 may be connected in series with the source of electrical potential and a utilization device adapted to respond to the electrical pulses so generated.

When the rotatable switch 10 is rotated in the clockwise direction as viewed in FIG. 15, the switch wiper part 16, which frictionally engages the pulse wheel part 12, is free to rotate in the clockwise direction until it reaches and contacts the projection 116 (shown in dashed lines in FIG. because it and the portion of the printed circuit card part which carries it are removed to show the movement of the wiper part 16). When this occurs, the contact rivet 72 of the switch wiper part 16 engages the metal film contact 104 of the printed circuit board part 20, which contact is connected to the terminal 110. Thus, the switch wiper part 16 so positioned completes an electrical circuit, the path of which is as follows: from contact terminal 114, through the conductive-metal ring 102 of the printed circuit board part 20, the spring washer part 18, the switch wiper part contact 72, the metal film contact 104, and the interconnect 108 to the terminal 110. Thus it may be seen, that the circuit between terminals 110 and 114 is closed if the rotatable switch 10 is rotated in the clockwise direction.

Conversely, if the rotatable switch 10 is rotated in the counterclockwise direction as viewed in FIG. 15, the switch wiper part 16 is caused to rotate counterclockwise until stopped by the projection 116, see the dashed lines of FIG. 15. In this position the contact rivet 72 engages the metal film contact 106 which is electrically isolated, thereby providing an open circuit between terminals and 114. Thus, it should be apparent that the open or closed circuit conditions corresponding to the counterclockwise or clockwise rotation of the switch 10 can be used to electrically indicate the direction of switch rotation.

In conclusion, the rotatable switch 10 of the present invention is comprised of parts which can be economically manufactured and assembled to provide an electrical device for generating pulses corresponding to a particular direction or rotation chosen by an operation, and, in addition, provide an electrical indication of the direction of rotation.

Obviously, many modifications and variations are possible in view of the above teachings. Therefore, it is to be understood that the invention may be practiced otherwise than as specifically described.

I claim:

1. A rotatable switch for providing electrical pulses and an indication of the direction of switch rotation, comprising printed circuit means including an inner surface portion having a plurality of annularly positioned conductive film segments spaced apart by nonconductive segments, first and second annular conductive films, a conductive film contact, and a stop projecting from the inner surface portion,

means for connecting operating potentials to said conductive film segments, said first and second annular conductive film, and said contact,

nonconductive means rotatably mounted to said printed circuit means and having affixed for rotation therewith electrically innerconnected contact means, one of said contact means being positioned to contact said first annular conductive film of said printed circuit means and another of said contact means being positioned to sequentially contact said conductive film segments of said printed circuit means upon rotation of said nonconductive rotatable means,

a first conductive wiper means frictionally engaging said nonconductive rotatable means for rotation therewith and having contact means positioned to engage and disengage the conductive film contact of said printed circuit means, said rotatable conductive wiper means having means positioned to cooperate with said stop of said printed circuit means to limit the rotation thereof in both directions, and

a second conductive wiper means secured for rotation with said nonconductive rotatable means and arranged to provide an electrical connection between said first conductive wiper means and said second annular conductive film of said printed circuit means.

2. A rotatable switch for providing electric pulses and an indication of the direction of switch rotation, comprising printed circuit means, including a plurality of spaced-apart conductive elements affixed to one surface thereof,

means for connecting operating potential to said conductive elements of said printed circuit means,

said printed circuit means further including a stop projecting from said surface to which said conductive elements are affixed,

nonconductive means rotatably mounted to said printed circuit means and carrying a plurality of contacts arranged in a predetermined relationship to register with said conductive elements of said printed circuit means, at least one of said contacts rotating with the rotation of said nonconductive means and one other contact means cooperating with said stop of said printed circuit meaNs and being limited in its rotation thereby between two switch positions depending upon the direction of rotation of said nonconductive rotatable means and means providing electrical connections to said spaced-apart conductive elements, said electrical connection means including one circuit which comprises said one other contact means of said nonconductive rotatable means and one of said conductive elements of said printed circuit means and another circuit which comprises said other contact means and another of said conductive elements when said other contact means is rotated to contact said another conductive element of said printed circuit means. 3. The rotatable switch as defined in claim 2, wherein said other contact means is mechanically coupled to said nonconductive rotatable means by a generally annularshaped conductive ring member having an opening within which is received said stop ofsaid printed circuit means, said annular ring member being arranged to make frictional engagement with said nonconductive rotatable means.

4. The rotatable switch as defined in claim 3, wherein the electrical connection between said other contact means of said nonconductive means and said another of said conductive elements of said printed circuit means includes a conductive washer rotatably secured to said nonconductive rotatable means and making contact with said annular ring member.

5. A rotatable switch for providing electrical pulses corresponding to the speed of rotation and an indication of the direction of switch rotation, comprising a member having a surface upon which a plurality of conductive elements spaced apart secured and spaced-apart in a predetermined relationship with respect to one another, said member further including a projection which extends outwardly from said surface,

means for connecting operating potential to said conductive elements,

nonconductive means rotatably mounted to said member and carrying a plurality of contacts arranged in a predetermined relationship and registering with the respective conductive elements of said member to provide the pulses corresponding to the speed of rotation and one of said contacts being mechanically coupled to said nonconductive means and cooperating with said projection of said member such that it is free to rotate between two positions depending upon the direction of rotation of said nonconductive means, and

means for providing an electrical circuit between said one contact carried by said nonconductive means and one of said conductive elements of said member, which said one contact may be caused to contact upon rotation of said nonconductive rotatable means in one direction to provide the indication of switch rotation

Claims

1. A rotatable switch for providing electrical pulses and an indication of the direction of switch rotation, comprising printed circuit means including an inner surface portion having a plurality of annularly positioned conductive film segments spaced apart by nonconductive segments, first and second annular conductive films, a conductive film contact, and a stop projecting from the inner surface portion, means for connecting operating potentials to said conductive film segments, said first and second annular conductive film, and said contact, nonconductive means rotatably mounted to said printed circuit means and having affixed for rotation therewith electrically innerconnected contact means, one of said contact means being positioned to contact said first aNnular conductive film of said printed circuit means and another of said contact means being positioned to sequentially contact said conductive film segments of said printed circuit means upon rotation of said nonconductive rotatable means, a first conductive wiper means frictionally engaging said nonconductive rotatable means for rotation therewith and having contact means positioned to engage and disengage the conductive film contact of said printed circuit means, said rotatable conductive wiper means having means positioned to cooperate with said stop of said printed circuit means to limit the rotation thereof in both directions, and a second conductive wiper means secured for rotation with said nonconductive rotatable means and arranged to provide an electrical connection between said first conductive wiper means and said second annular conductive film of said printed circuit means.

2. A rotatable switch for providing electric pulses and an indication of the direction of switch rotation, comprising printed circuit means, including a plurality of spaced-apart conductive elements affixed to one surface thereof, means for connecting operating potential to said conductive elements of said printed circuit means, said printed circuit means further including a stop projecting from said surface to which said conductive elements are affixed, nonconductive means rotatably mounted to said printed circuit means and carrying a plurality of contacts arranged in a predetermined relationship to register with said conductive elements of said printed circuit means, at least one of said contacts rotating with the rotation of said nonconductive means and one other contact means cooperating with said stop of said printed circuit means and being limited in its rotation thereby between two switch positions depending upon the direction of rotation of said nonconductive rotatable means and means providing electrical connections to said spaced-apart conductive elements, said electrical connection means including one circuit which comprises said one other contact means of said nonconductive rotatable means and one of said conductive elements of said printed circuit means and another circuit which comprises said other contact means and another of said conductive elements when said other contact means is rotated to contact said another conductive element of said printed circuit means.

3. The rotatable switch as defined in claim 2, wherein said other contact means is mechanically coupled to said nonconductive rotatable means by a generally annular-shaped conductive ring member having an opening within which is received said stop of said printed circuit means, said annular ring member being arranged to make frictional engagement with said nonconductive rotatable means.

5. A rotatable switch for providing electrical pulses corresponding to the speed of rotation and an indication of the direction of switch rotation, comprising a member having a surface upon which a plurality of conductive elements are secured and spaced-apart in a predetermined relationship with respect to one another, said member further including a projection which extends outwardly from said surface, means for connecting operating potential to said conductive elements, nonconductive means rotatably mounted to said member and carrying a plurality of contacts arranged in a predetermined relationship and registering with the respective conductive elements of said member to provide the pulses corresponding to the speed of rotation and one of said contacts being mechanically coupled to said nonconductive means and cooperatinG with said projection of said member such that it is free to rotate between two positions depending upon the direction of rotation of said nonconductive means, and means for providing an electrical circuit between said one contact carried by said nonconductive means and one of said conductive elements of said member, which said one contact may be caused to contact upon rotation of said nonconductive rotatable means in one direction to provide the indication of switch rotation.