US3928740A

US3928740A - Rotary switch

Info

Publication number: US3928740A
Application number: US444365A
Authority: US
Inventors: Gottfried Alsch
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-02-23
Filing date: 1974-02-21
Publication date: 1975-12-23
Anticipated expiration: 1992-12-23
Also published as: IT1009171B; BE811351A; FI59180B; CA1000329A; DK142826B; GB1454566A; SE395790B; CH580331A5; AT328026B; JPS49135172A; FR2219512A1; FI59180C; NL7402211A; DE2408053A1; FR2219512B1; ZA741063B; DK142826C; ATA162773A; AU6597874A

Abstract

A rotary switch comprises a housing defining a first set of guide grooves wherein a set of spring-biased plungers are glidably mounted for operating a set of contact bridges. A cam disc is mounted in the housing for rotation about an axis. The plungers are biased into contact with the cam disc and rotation of the cam disc causes movement of selected ones of the contact bridges perpendicularly to the axis of rotation. A star wheel is mounted in the housing coaxially with the cam disc for rotation therewith and a set of spring-biased detent elements is glidably mounted in a second set of guide grooves defined in the housing for cooperation with the star wheel.

Description

United States Patent 1191 Alsch Dec. 23, 1975 ROTARY SWITCH 2,892,047 6/1959 Smith 200/153 LB x Inventor: Gottfried c Vienna, Austria 3,566,051 2/1971 Hulterstrum 200/153 LB X [73] Assignee: Hubert Lauren'z Naimer,,Vienna, FOREIGN PATENTS OR APPLICATIONS Austria 1,517,882 3/1968 France ZOO/153 LB 2] Filed: 9 1974 Primary ExaminerRobert K. Schaffer 1 Appl No; 444,365 Assistant Examinerwilliam J. Smith Attorney, Agent, or FzrmKurt Kelman [30] Foreign Application Priority Data [57] I ABSTRACT Feb. 23, 1973 Austria 1627/73 A rotary switch Comprises a housing defining a first Set 1 I of guide grooves wherein a set of spring-biased plungg 1 ers are glidably mounted for operating a set of contact n e l e l t u A [58] new of Search ZOO/153 tation about an axis. The plungers are biased into 17 18 contact with the cam disc and rotation of the cam disc 56 R f ed causes movement of selected ones of the contact brid- 1 e erences It ges perpendicularly to the axis of rotation. A star UNITED STATES PATENTS wheel is mounted in the housing coaxially with the 2,030,890 2/1936 Oberhofiken 200/153 LB cam isc for rotation therewith and a set of spring- 2,245,369 6/1941 Smith 200/ 153 LB biased detent elements is glidably mounted in a sec- 2398307 4/ 1946 200/ 153 L3 X ond set of guide grooves defined in the housing for 00- 2,684,412 7/1954 Bauer 200/153 LB x Operation with the Star WheeL 2,786,105 3/1957 Pawley et al 200/153 LB X 2,823,285 2/1958 Stone 200/153 LB 3 Claims, 3 Drawing Figures US. Patent Dec. 23, 1975 3,928,740

ROTARY SWITCH The present invention relates to improvements in rotary switches.

Conventional rotary switches comprise a housing defining a set of guide grooves and a set of springbiased plungers glidably mounted in the set of guide grooves. The plungers are operably associated with respective ones of a set of contactbridges mounted in the housing and a cam disc is mounted in the housing for rotation about an axis. The plungers being biased into contact with the cam disc, rotation thereof causes movement of selected ones of the contact bridges perpendicularly to the axis of rotation in response to the configuration of the camming surface of the cam disc. A rotary switch of this type requires detent means arranged to hold the cam disc in predetermined rest positions wherein no movement of the plungers is caused.

Usually, this detent means is constituted by a separate structural part with its own housing connected to the switch housing proper by bolts or a bayonet coupling. This increases not only thecost of construction but also the axial length of the switch unit.

It has also been proposed to mount the detent mechanism in the switch housing and to use the cam disc of the switch also as a star wheel forming part of the detent mechanism. However, the usefulness of this structure is limited because the detents of the combined cam disc-star wheel also operate as camming surfaces causing movement of the plungers so that the desired operation of the switch is difficult to control.

It is the primary object of this invention to overcome these difficulties and disadvantages and to produce a rotary switch of the type wherein the cam disc and detent mechanism are mounted in a single switch housing but the cam-controlled operation of the switch contacts is not impaired by the detent mechanism.

The above and other objects are accomplished in accordance with the invention with a rotary switch which comprises a housing defining a first set of guide grooves and a second set of guide grooves. A set of contact bridges is mounted in the housing and a set of spring-biased plungers is mounted glidably in the first set of guide grooves and is operably associated with respective ones of the contact bridges to move them in response to the movement of the associated plungers. A cam disc is mounted in the housing for rotation about an axis, the plungers being biased into contact with the cam disc and rotation of the cam disc causing movement of selected ones of the contact bridges perpendicularly to the axis of rotation in response to the configuration of the camming surface of the cam disc. A star wheel is mounted in the housing coaxially with the cam disc and coupled thereto for rotation therewith and a set of spring-biased detent elements is mounted in the second set of guide grooves for cooperation with the star wheel.

A rotary switch of this structure is particularly useful when the set of contact bridges consists of two diametrically opposed contact bridges, in which case the second set of guide grooves also consists of two diametrically opposed guide grooves, and the axes of the plungers and the two opposed guide grooves for the detent elements are angularly spaced from each other by 90.

According to a preferred feature, the detent elements define bores housing springs for biasing the detent elements, and mating guide or retaining means hold the preferred embodiment thereof, taken in conjunction with the accompanying drawing wherein FIG. 1 is a top view of the switch mechanism, showing the interior of the switch housing, with the cover removed;

FIG. 2 is a bottom view showingthe detent mechanism; and

FIG. 3 shows a sectional view along line IIIIII of FIG. 2.

Referring now to the drawing, the illustrated rotary switch comprises housing part 1 and cam disc 2 mounted centrally therein for rotation about an axis, the axis of rotation being defined by a shaft (not shown) to which the cam disc is keyed by teeth 3. The cam disc of the switch may also be coupled to a like or similar rotary switch mounted axially adjacent thereto.

Housing 1 defines a first set of two radially extending, diametrically opposed guide grooves 4 wherein plungers 5 are glidably mounted, each plunger being operably associated with a respective one of contact bridges 6. In the illustrated embodiment, the plungers carry the contact bridges for movement therewith. Compression springs 7 bias the plungers inwardly into contact with cam disc 2 and rotation of the cam disc causes movement of a selected one of the contact bridges perpendicularly to the axis of rotation in response to the configuration of the camming surface of the cam disc, as clearly shown in FIG. 1. Switch contacts 8 are mounted in grooves in the switch housing for cooperation with the contact bridges so that movement of the selected contact bridge closes a selected switch contact. The contact terminals are shown at 10. All of this structure is substantially conventional.

In accordance with this invention, the housing defines a second set of

guide grooves

11 and 12, the diametrically opposed, radially extending

guide grooves

11 and 12 being angularly spaced from the axes of plungers 5 to Detent elements 13 are glidably mounted in

grooves

11 and 12 for cooperation with star wheel 14 (see FIG. 2). The star wheel is mounted in the housing coaxially with cam disc 2 and axially adjacent thereto, the cam disc and star wheel being coupled together for common rotation and forming a single structural unit. If desired, the cam disc and star wheel may be integral with each other.

The structure of the detent elements is best shown in FIGS. 2 and 3. As illustrated, each detent element 13 is a slide having a pair of lateral guide grooves 15 cooperating with a mating pair of guide rails 16 in the side walls of guide grooves l1, 12 so as to hold the detent elements in their guide grooves against movement outwardly of their guide grooves in the direction of the axis of rotation (see arrow A in FIG. 3). Also, the detent elements define cylindrical bores 17 housing springs 18 for biasing the detent elements against the star wheel. The ends of compression springs 18 abut against the bottoms of the guide grooves ll, 12 and bores 17, respectively, as best shown in FIG. 2.

ln assembling the rotary switch, spring-biased detent elements 13 are first inserted into their

guide grooves

11, 12 through the center recess 21 of housing part 1, whereupon the cam disc-star wheel unit is mounted in 3 the center recess. Plungers 5 may now be mounted in their guide grooves 4 to complete the assembly.

It will be obvious from the above description that a rotary switch of the described structure is not only compact by providing a single structural unit of cam disc and detent mechanism while assuring independent operation of the cam disc and the detent mechanism but, at the same time, meets all operational requirements for such switches. Furthermore, the axial length of the switch is reduced, thus saving material and space.

It will be useful to make all of the switch parts, including the housing part 1, the cover (not shown), the cam disc and the star wheel by injection molding a thermoplastic synthetic resin, except, of course, the parts which must be electrically conductive and the springs.

What is claimed is:

1. A rotary switch having an axis of rotation and comprising:

a. a housing defining a plurality of first radial guide grooves and a second radial guide groove axially adjacent said first guide grooves and angularly spaced from each of said first grooves;

b. a plunger radially movable in each of said first grooves;

c. a cam disc mounted in said housing for rotation about said axis and having a cam face opposite said first grooves;

(ill

d. first yieldably resilient means biasing each plunger toward engagement with cam face;

e. a star wheel secured to said cam disc for joint rotation about said axis;

f. a detent element radially movable in said second groove;

g. second yieldably resilient means biasing said detent element toward engagement with said star wheel; and

h. a plurality of contact bridges mounted in said housing and operatively connected to respective ones of said plungers for operation when the connected plungers are moved during rotation of said cam disc against the biasing of said first yieldably resilient means.

2. The switch of claim 1, wherein said first grooves are equiangularly distributed about said axis, said second groove bi-secting the angle between two adjacent first grooves.

3. The switch of claim 1, wherein said housing defines an additional, second, radial guide groove angularly spaced from each of said first guide grooves, the switch including additional detent element radially movable in said additional second groove, and additional yieldably resilient means biasing said additional detent element toward engagement with said star

Claims

1. A rotary switch having an axis of rotation and comprising: a. a housing defining a plurality of first radial guide grooves and a second radial guide groove axially adjacent said first guide grooves and angularly spaced from each of said first grooves; b. a plunger radially movable in each of said first grooves; c. a cam disc mounted in said housing for rotation about said axis and having a cam face opposite said first grooves; d. first yieldably resilient means biasing each plunger toward engagement with cam face; e. a star wheel secured to said cam disc for joint rotation about said axis; f. a detent element radially movable in said second groove; g. second yieldably resilient means biasing said detent element toward engagement with said star wheel; and h. a plurality of contact bridges mounted in said housing and operatively connected to respective ones of said plungers for operation when the connected plungers are moved during rotation of said cam disc against the biasing of said first yieldably resilient means.

3. The switch of claim 1, wherein said housing defines an additional, second, radial guide groove angularly spaced from each of said first guide grooves, the switch including additional detent element radially movable in said additional second groove, and additional yieldably resilient means biasing said additional detent element toward engagement with said star wheel.