US3311718A

US3311718A - Rotary electric switch with improved internal actuating and contact structure including tolerance compensator means

Info

Publication number: US3311718A
Application number: US464255A
Authority: US
Inventors: Kenneth C Allison; Thomas R Beaver
Original assignee: CTS Corp
Current assignee: CTS Corp
Priority date: 1965-04-14
Filing date: 1965-04-14
Publication date: 1967-03-28
Anticipated expiration: 1984-03-28
Also published as: GB1148723A

Description

M h 8. 1967 K. c. ALLISON ETAL' 18 ROTARY ELECTRIC SWITCH WITH IMPROVED INTERNAL ACTUATING AND CONTACT STRUCTURE INCLUDING TOLERANCE COMPENSATOR MEANS Filed April 14, 1965 2 Sheets-Sheet l /a =FIGURE 2.

39 //w INVENTORS 3 KENNETH C. ALLISON THOMAS R. BEAVER BY AT ORNEY March 28. 1967 K. c. ALLISON ETAL ,3 v

ROTARY ELECTRIC SWITCH WITH IMPROVED INTERNAL ACTUATING AND CONTACT STRUCTURE INCLUDING TOLERANCE COMPENSATOR MEANS Filed April 14, 1965 2 Sheets-Sheet 2 FIGURE 3 FIGR 5 INVENTORS KENNETH C. ALLISON THOMAS R. BEAVER United States Patent 3,311,718 ROTARY ELECTRIC SWITCH WITH IM- PROVED INTERNAL ACTUATING AND CONTACT STRUCTURE INCLUDDIG TOLERANCE COMPENSATOR MEANS Kenneth C. Allison, Crystal Lake, 11]., and Thomas R. Beaver, Elkhart, Ind, assignors to CTS Corporation, Ellrhart, lnd., a corporation of Indiana Filed Apr. 14, 1965, Ser. No. 464,255 16 Claims. (Cl..20ll11) The present invention relates to switches, and, more particularly, to a miniature rotary electric switch.

In order to obtain accurate operation and wiping action between a movable contactor and a plurality of stationary contacts as the size of the parts of a switch decreases, it is necessary to maintain the parts to closer than standard tolerances. Manufacturing such parts to closer than standard tolerances, however, increases the cost of the switch considerably. It would, therefore, be desirable to provide an improved miniature rotary electric switch with parts having standard manufacturing tolerances and employing a tolerance compensator for counteracting variations resulting from the tolerances.

As the size of a switch decreases, the switch is more difiicult to design, especially the design of the movable contactor engageable with the stationary contacts. Genintegral with a spring arm but, as the length of a spring arm decreases, the ability to maintain a defined contact pressure over a predetermined distance decreases. It would, therefore, also be desirable to provide a miniature electric switch with a movable spring eontactor employing a torsion bar for maintaining uniform contact pressure.

Another ditficulty with miniaturization of electrical switches of the rotatable type is to provide adequate strength in a stop assembly for halting rotation of the switch when desired without shearing the shaft or a part of the stop assembly. Generally when a stop arm engages a fixed stop or shoulder in the housing for halting rotation, the dimension of the stop arm and the shoulder as well as the shaft are decreased as the size of the switch is decreased. It would, therefore, be desirable to decrease the overall size of the stop assembly without decreasing the stop strength thereof.

Accordingly, it is an object of the present invention to provide an improved miniature rotary electric switch with a tolerance compensator.

Another object of the present invention is to provide a miniature rotary electric switch with a torsion bar spring contactor.

An additional object of the present invention is to provide a miniature rotary electric switch with improved stop strength.

A further object of the present invention is to provide a miniature rotary electric switch with a detent mechanism having a U-shaped detent cage fixedly secured to a shaft and a stop integral with the cage.

Another object of the present invention is to provide a miniature rotary electric switch adapted for single-pole or multi-pole operation.

Still an additional object of the present invention is to provide a miniature rotary electric switch with a housing having axial and radial bearings for supporting a shaft axially and radially.

Further objects and advantages of the present invention will become apparent as the following description proceeds, and the features of novelty characterizing the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Briefly, the present invention is concerned with an improved miniature rotary electric switch comprising a cupshaped housing defining a chamber open at one end. A

Patented Mar. 28, 1967 contact carrier supporting a plurality of stationary contacts closes the one end of the chamber. Axial and radial bearing surfaces are provided in the housing for rotatably supporting a shaft. A torsion bar spring contactor for wiping engagement with the stationary contacts is carried by a driver constrained to rotate with the shaft. Interposed between the detent mechanism and the driver and operably coupling the detent mechanism to the driver is a tolerance compensator biasing the shaft outwardly of the housing and the driver against the contact car-rier, thereby counteracting variations due to tolerances and enabling the switch to be constructed from parts containing standard manufacturing tolerances. The torsion bar spring contactor is provided with a pair of contact arms extending from diametrically opposite ends of a torsion bar to provide adequate spring pressure during operation of the switch. Indexing of the switch is obtained with a detent mechanism fixedly secured to the end of the shaft and a stop arm integral with the detent mechanism limits rotation of the shaft.

For a better understanding of the present invention, reference may be had to the accompanying drawings wherein the same reference numerals have been applied to like parts and wherein:

FIGURE 1 is an enlarged isometric view of a miniature rotary electric switch;

FIGURE 2 is a sectional view taken along line II-II of the svw'tch shown in FIGURE 1;

FIGURE 3 is an exploded view of the switch shown in FIGURE 1;

FIGURE 4 is a sectional view of a torsion bar spring contactor shown in FIGURES 2 and 3 of the drawings; and

FIGURE 5 is a top view of an index sleeve best shown in FIGURE 3 of the drawings.

Referring now to the drawings and, more particularly, to FIGURES 2 and 3 thereof, there is illustrated a miniature rotary electric switch 10 comprising a cup-shaped housing 11 defining a chamber 12 having an opening 13 at one end thereof, a contact carrier 20 closing the open end of the chamber, a detent assembly 30 mounted in the housing for indexing a spring contactor 50 for wiping engagement with a plurality of stationary contacts 22 and a tolerance compensator 40.

Considering first the housing 11 it is provided with a forwardly projecting threaded bushing 15 for securing the housing to a not-shown mounting panel or the like with a nut. A pair of flat surfaces 15a on the bushing'assures proper alignment of the switch in the mounting panel. Concentric with the bushing 15 at the front end of the housing is an annular groove 16 containing an O-ring 17 for sealing the housing to the mounting panel. The cylindrical portion 11a of the housing adjacent to the open end thereof is provided with an inwardly extending projection 18 located in a slot 21 in the periphery of the contact carrier 20 and properly aligning the contact carrier at the open end of the housing. The peripheral edge 11b of the housing is rolled over as shown in FIGURES 1 and 2 of the drawings to secure the contact carrier to the housing. A shoulder 19 prevents inward movement of the contact carrier 20. A plurality of circumferentially spaced stationary contacts 22 are generally insert molded or inserted into slots provided in the contact carrier 20 and then staked to secure the stationary contacts 22 to the contact carrier. To seal the contact carrier to the housing, a layer of epoxy 23 or suitable insulating material is applied to the outer surface of the contact carrier.

The threaded bushing 15 is provided with a bore 15b rotatably supporting a shaft 24- extending into the sealing portion 12:: of the chamber 12. Sealing the exterior front end of the housing '11 from the chamber 12 is effected with another O-ring 25 compressed between the shaft and cylindrical wall of the sealing portion 12a as best shown in FIGURE '2 of the drawings. A pair of peripheral shoulders 26 integral with the shaft prevent movement of the O-ring 25 on the shaft 24. Preferably the bearing face 26a of the outer peripheral shoulder 26 engages the upper wall or bearing surface 12b of the sealing section providing a shaft bearing normal to the bearing between the shaft and the bore 15b, the former being referred to as a radial bearing and the latter being referred to as an axial bearing.

In accord with the present invention, indexing of the switch 10 is effected with the detent assembly 30 fixedly secured to the shaft 24- extending in the chamber 12.

More specifically, the detent assembly comprises a rotatable U-shaped cage 31 having an elongated slot 31a (see FIGURE 2) in the bight portion thereof, and a wide tongue 24a integral with the end of the shaft 241- fits into the elongated slot 31a. The shaft 24 is fixedly secured to the cage 31 by staking the tongue. A detent or index sleeve 32. as best shown in FIGURES 3 and of the drawings is disposed in the front portion of the chamber 12 around the cage 31 and rearward movement of the sleeve is prevented by shoulders formed by inward depressions 11c. A dimple 33 in the wall of the housing 1'1 forming an inwardly extending projection in the chamber wall and located in a slot 32a provided in the rim of the index sleeve 32 properly aligns the sleeve in the housing. The index sleeve is provided with a plurality of spaced downwardly extending curved fingers 32b. A pair of detent balls 34, each ball being greater in diameter than the distance between adjacent fingers, are biased against the index sleeve by a coiled helical spring 35 disposed in the U-shaped cage 31. Each of the balls 34 assumes a stable position when disposed in a space between adjacent. fingers. The number of detent positions of the switch is altered by changing the number of curved fingers 32b on the index sleeve 32 and the number of stationary contacts 22.

Preferably and as best illustrated in FIGURE 5 of the drawings, the index sleeve 32 is provided with an inwardly extending arcuate stop member 36 engageable by an upwardly extending stop arm 37 of the rotatable U-shaped cage 31 for halting rotation of the shaft. The angle of rotation of the shaft is limited to the angle defined by the removed portion of the arcuate stop member.

As will become apparent from the following description, a driver 39 is operably coupled to the U-shaped cage 31 by means of a tolerance compensator 40. Considering first the driver 39, it is preferably cup-shaped and of molded construction having an elongated groove 39a extending across and intersecting a pair of spaced transverse grooves 3% receiving the spring contactors 50 to provide a two-pole switch. The number of poles of the switch is altered by changing the number of spring contactorsStl, e.g., one spring contactor 50 is employed when a single-pole switch is desired. Each of the spring contactors 50 comprises an elongated torsion bar 51 lying in the transverse slots 3%. Dimples 51a on each end of the torsion bar 51 provide a two point support. Extending outwardly from diametrically opposite ends of the torsion bars are a pair of contact arms 52 having a connecting portion 52a extending substantially normal to the torsion bar, and a contact carrying portion 52b extending in spaced parallel relationship to the torsion bar and carrying a contact button 520. Preferably each of the contact buttons 520 is disposed in a plane bisecting the torsion bar transversely, and the contact arm is preformed at an angle to the major plane of the torsion bar. Forming a small angle in the torsion bar 51 as shown in FIGURE 5 of the drawings assures that a space is maintained between the center of the torsion bar and the bottom wall of the slot 3% to facilitate twisting of the torsion bar as the spring contactor 50 is wiped on the contacts 22. The contact button adjacent to the center of the driver engages a stationary center contact 22a while the other contact button adjacent to the cylindrical wall 39c of the driver 39 engages the circumferentially spaced stationary contacts as the driver is rotated.

Securing of the tolerance compensator 40 to the U- shaped cage 31 is performed by suitable means such as staking a plurality of ears 31b located in the openings 40a of the tolerance compensator 40. The driver 39 is also provided with a pair of apertures 41 and a center aperture 42 receiving a pair of downwardly extending outer legs 43 and a center tab 44 of the tolerance compensator 40. The outer legs 43 and the center tab 44 extending into the apertures 41 and 4 2 of the driver constrain the driver to rotate therewith and with the shaft by means of the U-shaped cage 31. pensator of spring material has a pair of preformed end portions or wings 119b biasing the driver against the contact carrier 20. With the above-described arrangement, variations in manufacturing tolerances are overcome by the tolerance compensator 40 with the legs 43 moving slightly inwardly or outwardly of the apertures 41. As will become apparent from the above description, the rim of the circumferential wall 390 of the driver engages the contact carrier and functions as a bearing. Although it is preferable that the face 26a of the peripheral shoulder 26 integral with the shaft also engages the inner wall 12b of the chamber due tothe biasing force of the compensator 40, it is feasible to have the U-shaped cage 31 engage the peripheral lip 11d to provide another hearing, such bearing is not desirable since the area of contact is less than 360 degrees. In any event, the switch 10 is provided with three bearings. when the axial hearing supporting the rotatable shaft 24 in the bushing is included. Furthermore, by controlling the thickness of the spring material of the tolerance compensator and by controlling the preformed angle of the wings 40b of the tolerance compensator 40 engaging the driver, various rotational torques are obtainable.

For the purposes of limiting end thrust or inward movement of the shaft, a circumferential slot 24b provided in the shaft retains a C-ring 45 for engaging the end of the threaded bushing 15 should excessive axial pressure be applied to the shaft.

While there has been illustrated and described what is at present considered to be a preferred embodiment of the present invention, it will be appreciated that numerous changes and modifications are likely to occur to those skilled in the art, and it is intended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention.

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

1. In a switch, the combination of a cup-shaped housing defining a chamber open at one end, a contact carrier closing the open end of the chamber, a shaft rotatably mounted in the housing and having one end extending into the chamber, a plurality of circumferentially spaced stationary contacts carried by the contact carrier and extending into the chamber, a stationary center contact carried by the contact carrier, a driver disposed in the chamber and constrained to rotate with the shaft, a tolerance compensator biasing the driver against the contact carrier and the shaft outwardly of the housing, a movable contactor carried by the driver for wiping engagement with the stationary center contact and the circumferentially spaced stationary contacts upon rotation of the shaft, and indexing means for positioning the shaft in a plurality of positions.

2. In a switch, the combination of a cup-shaped housing defining a chamber open at one end, a contact carrier closing the open end of the chamber, a shaft rotatably mounted in the housing and having one end extending into the chamber, a plurality of circumferentially spaced stationary contacts carried by the contact carrier and extending into the chamber, a stationary center contact The tolerance comcarried by the contact carrier, contactor means for wiping engagement with the stationary contacts, a detent member having a U-shaped crosssection, the bight portion of the U being secured to the one end of the shaft, a coiled helical spring trapped by the detent member, a detent sleeve having a plurality of radially spaced indexing fingers disposed in the chamber in concentric relationship to the shaft, a pair of detent balls engaging the ends of the spring and biased against the indexing fingers, the diameter of the detent balls being greater than the space between adjacent indexing fingers, a stop member mounted in the housing, and a stop arm carried by the detent member engageable with the stop member for limiting angular rotation of the shaft.

3. In a switch, the combination of a housing having a pair of spaced end walls defining a chamber therebetween, a shaft rotatably journaled in one of the end walls of the housing, a plurality of circumferentially spaced stationary contacts mounted in the other end wall of the housing and extending into the chamber, a stationary center contact mounted in the other end Wall, a driver disposed in the chamber and rotatable with the shaft, a spring contactor carried by the driver and constrained to rotate therewith, the spring contactor comprising a torsion bar, a pair of contact arms extending from diametrically opposite ends of the torsion bar and provided with a pair of contact buttons for wiping engagement with the stationary contacts as the shaft is rotated.

4. In a switch, the combination of a housing provided with a chamber, a plurality of stationary contacts carried by the housing and extending into the chamber, a shaft journaled in the housing, a rotatable driver mounted in the chamber and operably connected to the shaft, a spring contactor constrained to rotate with the driver and engageable with at least a pair of the stationary contacts, said spring contactor comprising a torsion bar, a pair of arms connected to diametrically opposite ends of the torsion bar, each arm having a connecting portion and a contact carrying portion, the connecting portions extending outwardly from and normal to the major axis of the torsion bar, the contact carrying portions extending toward each other in spaced parallel planes, a contact button carried by each of the contact carrying portions for wiping engagement with the stationary contacts upon rotation of the driver, and means for incrementally rotating the driver.

5. A switch comprising a housing, a plurality of stationary contacts extending outwardly from one end of the housing, a driver mounted in the housing, a movable spring contacto-r engageable with at least a pair of contacts and constrained to rotate with the driver, a shaft rotatably journaled in the housing and operably connected to the driver, a detent mechanism secured to the shaft, and a tolerance compensator urging the driver into engagement with the one end of the housing and the detent mechanism toward the other end of the housing.

6. In an electric switch having a housing provided with a chamber, a shaft journaled in the housing, a plurality of circumferentially spaced stationary contacts extending outwardly from one end of the housing and extending into the chamber, and a spring contactor for wiping engagement with the contacts, the improvement comprising a cup-shaped driver slideably mounted on the one end of the housing, a peripheral shoulder extending radially outwardly from the shaft and provided with a radial bearing surface engaging a bearing surface in the other end of the housing normal to the longitudinal axis of the shaft. 7. The switch of claim 6, wherein a tolerance compensator biases the driver against the one end of the housing and the peripheral shoulder against the other end of the housing.

8. In a switch, the combination of a cup-shaped housing defining a chamber open at one end, a contact carrier closing the open end of the chamber, a shaft rotatably mounted in the housing and having one end extending into the chamber, a plurality of circumferentially spaced stationary contacts carried by the contact carrier and extending into the chamber, a stationary center contact carried bythe contact carrier, a driver disposed in the chamber and constrained to rotate with the shaft, a tolerance compensator biasing the driver against the contact carrier and the shaft outwardly of the housing, the driver being provided with a plurality of apertures, a plurality of legs integral with the compensator slideably mounted in the apertures, a movable contactor carried by the driver for wiping engagement with the stationary center contact and the circumferentially spaced stationary contacts upon rotation of the shaft, and indexing means for positioning the shaft in a plurality of positions.

9. In a switch, the combination of a housing provided with a chamber open at one end, a contact carrier closing the open end of the chamber, a shaft rotatably mounted in the housing and extending into the chamber, a plurality of stationary contacts carried by the contact carrier and extending into the chamber, contactor means for wiping engagement with the stationary contacts, a detent member having a U-shaped cross section, the bight portion of the U being secured to the shaft, an index sleeve having a plurality of radially spaced fingers disposed in the chamber in concentric relationship to the shaft, detent means carried by the detent member and biased against the fingers, an arcuate stop member integral with the index sleeve and a stop arm carried by the detent member engageable with the stop member for limiting angular rotation of the shaft;

it In a switch, the combination of a cylindrical housing having a pair of spaced end walls defining a chamber therebetween, a shaft rotatably journaled in one of the end walls of the housing, a plurality of stationary contacts mounted in the other end wall of the housing and extending into the chamber, a driver disposed in the chamber and rotatable with the shaft, a means spacing the driver from the other end wall, a spring contactor carried by the driver and constrained to rotate therewith, the spring contactor comprising a torsion bar, a pair of contact arms extending from diametrically opposite ends of a torsion bar having a pair of contact buttons for wiping engagement with the stationary contacts as the shaft is rotated.

11. In a switch, the combination of a housing provided with a first chamber and a second chamber having a cylindrical wall, a plurality of stationary contacts mounted in the housing, a bushing having a bore extending into the second chamber, a shaft journaled in the bore, the second chamber having a diameter larger than the diameter of the bore, a pair of spaced cylindrical members integral with the shaft and disposed in the second chamber, a sealing washer interposed between the cylindrical members and compressed between the shaft and the cylindrical wall, a rotatable driver mounted in the second chamber and operably connected to the shaft, a spring contactor constrained to rotate with the driver and engageable with at least a pair of the stationary contacts, and means for incrementally rotating the driver.

12. The switch of claim 11, wherein the spring contaca tor comprises a torsion bar, a pair of arms are connected to diametrically opposite ends of the torsion bar, each arm having a connecting portion and a contact carrying portion, the connecting portions extending outwardly from and normal to the major axis of the torsion bar, the contact carrying portions extending toward each other in spaced parallel planes, and a contact button is carried by each of the contact carrying portions for wiping engagement with the stationary contacts upon rotation of the driver.

13. The switch of claim 11, wherein the driver is provided with a depending perpiheral flange for limiting the pressure of the spring contactor against the stationary contacts, the lip of the flange slideably engaging a bearing surface of the housing.

14. The switch of claim 13, wherein means overcoming the biasing force of the spring contactor biases the shaft outwardly and the driver against the bearing surface of the housing.

15. A switch comprising a housing, a plurality of sta- 'tionary contacts extending outwardly from one end of the housing, a driver mounted in the housing, a movable spring contactor engageable with at least a pair of contacts and constrained to rotate with the driver, a shaft rotatably journaled in the housing and operably connected to the driver, a detent mechanism secured to the shaft, a tolerance compensator, the tolerance compensator being the only driving connection between the shaft and the driver,

a pair of preformed wings integral with the tolerance compensator biasing the driver toward the one end of the References Cited by the Examiner UNITED STATES PATENTS 11/1957 Lefl'. et a1. 200-11 4/1961 Nabstedt 200-11 ROBERT K. SCHAEFER, Primary Examiner,

I. R. SCOTT, Assistant Examiner.

Claims

1. IN A SWITCH, THE COMBINATION OF A CUP-SHAPED HOUSING DEFINING A CHAMBER OPEN AT ONE END, A CONTACT CARRIER CLOSING THE OPEN END OF THE CHAMBER, A SHAFT ROTATABLY MOUNTED IN THE HOUSING AND HAVING ONE END EXTENDING INTO THE CHAMBER, A PLURALITY OF CIRCUMFERENTIALLY SPACED STATIONARY CONTACTS CARRIED BY THE CONTACT CARRIER AND EXTENDING INTO THE CHAMBER, A STATIONARY CENTER CONTACT CARRIED BY THE CONTRAINED TO ROTATE WITH THE SHAFT, A CHAMBER AND CONSTRAINED TO ROTATE WITH THE SHAFT, A TOLERANCE COMPENSATOR BIASING THE DRIVER AGAINST THE CONTACT CARRIER AND THE SHAFT OUTWARDLY OF THE HOUSING, A MOVABLE CONTACTOR CARRIED BY THE DRIVER FOR WIPING ENGAGEMENT WITH THE STATIONARY CENTER CONTACT AND THE CIRCUMFERENTIALLY SPACED STATIONARY CONTACTS UPON ROTATION OF THE SHAFT, AND INDEXING MEANS FOR POSITIONING THE SHAFT IN A PLURALITY OF POSITIONS.