Miniature Axial Bridging Rotary Switch With Improved Housing

Abstract

Multi-position electrical switch including switch sections or decks arranged so that any desired number of sections can be used. Each section includes a rotor for selectively bridging switch contacts which can be arranged in different manners as required in different applications. A large number of switch positions, for example, 24, can be provided in a very small switch structure. The individual contacts for the different positions are embedded in a plastic insulating member to provide a solid insulated support therefor.

Description

BACKGROUND OF THE INVENTION

A miniature multi-position rotary switch structure is described and claimed in my prior U.S. Pat. No. 3,297,836, issued Jan. 10, 1967. This switch has been highly successful in actual use and is being produced in large quantities by Grayhill, Inc., assignee of the invention. As described in the patent, this prior switch structure provides 12 switch positions, and it has also been constructed with 10 switch positions.

There has been a significant demand for miniature rotary switches having more than 12 positions. More specifically, switches are required in various applications which have 16, 20 and 24 positions. The switches which are available and which have such a large number of positions have been quite large, substantially larger than the switches constructed in accordance with U.S. Pat. No. 3,297,836. Although attempts have been made to provide smaller switches with 16 or more positions, the switches have not been entirely satisfactory in operation and have not been of a construction to provide the contact arrangements which are required in many applications.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a miniature multi-position rotary switch which is of simple construction and which can have as many as 16 or more switch positions.

Another object of the invention is to provide a multi-position rotary switch having a large number of switch positions, with the contacts required for such switch positions being embedded in closely spaced relation in an insulating support housing, and insulated from each other thereby.

A further object of the invention is to provide a miniature multi-position rotary switch which has a plurality of switch sections or decks, with a common operator therefore and independent contact structures, with each deck having a large number of switch positions.

In accordance with the invention, a miniature rotary electrical switch is provided including a base member to which a rotary actuator is connected, and which has a detent structure and a stop structure coupled thereto. One or more switch decks are connected to the base member, with the actuator extending through the switch decks to move the rotors thereof. Each switch deck includes a cylindrical insulating housing section having a plurality of conductors embedded therein at radially spaced positions. The conductors have portions extending outside the housing forming terminals, and portions extending inside the housing forming switch contacts. A rotor within each housing section has one or more contacts therein which selectively engage the contacts of the conductors embedded in the housing, and one or more other contacts provided on a plate which closes one end of the housing section. The other end of the housing section is closed by a disc having ridges extending therefrom into the spaces between the switch contacts. The ridges insure that the contacts are insulated from each other and form recesses or wells for receiving foreign particles, so that such particles are removed from the vicinity of the switch contacts. The ridges may extend into the path of the moving contacts, and serve to clean such contacts as they move from one position to the other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a miniature rotary multi-position switch in accordance with the invention;

FIG. 2 is a cross-section view of the switch of FIG. 1;

FIG. 3 is an exploded view of the switch of FIG. 2 showing only one switch deck;

FIG. 4 is a detail view showing the insulating rotor 49 and the U-shaped contact 50;

FIG. 5 illustrates the construction of the insulating disc of the switch; and

FIG. 6 illustrates a modification of the contact structure.

DETAILED DESCRIPTION

In FIG. 1 there is shown a miniature multi-position rotary switch of the invention which includes a base housing member 10 having a threaded tubular bushing 12 extending therefrom for mounting the same on a panel. A rotary operating shaft 14 extends through the bushing 12 for controlling the position of the switch. A plurality of switch sections or decks 15 and 16 are shown mounted to the base member 10 by a plurality of bolts 18. A cover plate 20 is provided after the last switch section 16. It is to be pointed out that any number of switch decks, from 1 to 12 or more, can be used, with the deck 16 being broken away to indicate that additional decks can be used. The switch is shown enlarged in the drawing to better illustrate the structure. A 24 position switch as illustrated may have an outer diameter of about 11/4 inches, and the thickness of each switch deck is about one third of an inch.

FIG. 2 is a cross-section view of the switch of FIG. 1, and FIG. 3 is an exploded perspective view showing such a switch with a single switch deck. As shown in FIG. 2, the operating shaft 14 has a slot 22 in the end thereof into which an actuating blade 24 is keyed. The blade 24 is held in position with an end thereof in the slot 22 by the cover plate 20. The base member 10 of the switch forms a housing in which a detent mechanism 27 is positioned. This mechanism includes an elongated rotor (FIG. 3) with opposing holes therein in which springs 28 are positioned. The springs 28 force balls 30 outwardly against the wall 31 of the housing recess 26, and has ribs thereon (FIG. 3) to form detented positions. The detent mechanism 27 is turned by the blade 24 as the switch operating shaft 14 is rotated.

A stop plate 32 is also provided in the recess 26 in the base member 10. This plate is also keyed to the blade 24, and has a projecting stop arm 33 which engages pins 34 in the base 10 to limit the rotary movement of the operating shaft 14. The pins 34 may be positioned in any desired ones of the openings 35 in the base 10, to limit the rotary movement of the shaft 14, as may be required.

Each switch section or deck includes a cylindrical housing member 36 which is molded of insulating material. This member has a plurality of conductors 38 embedded therein which are substantially uniformly radially positioned about the cylindrical housing 36. The conductors have outwardly extending terminal portions 39 and inwardly extending contact portions 40. The contact portions 40 may be bent upwardly to facilitate contact therewith by the rotor, as will be further explained. On the top side of the insulator 36 is an insulating cover plate 42, which has a recess 43 on the bottom side in which a common annular conductor 44 is placed. The conductor 44 has a terminal projection 45 to which electrical connection can be made.

Positioned within the housing 36 is a rotor structure 48 including an insulating member 49 having one or more contacts 50 movable thereby. The member 49 has a slot for receiving the blade 24, with the operating shaft 14 and the actuating blade 24 cooperating to form a rotary actuator for the rotor structure 48.

As shown in FIGS. 2 and 4, the movable contact 50 is U-shaped and has one arm selectively engaging the individual contacts 40 of the conductors 38 and another arm engaging the common conducting ring 44 (FIG. 2). The movable contact 50 is made of a resilient metal to provide spring biased engagement with the fixed contacts. It will be obvious that a plurality of contacts 50 can be positioned in the recesses provided in rotor 49 to simultaneously bridge a plurality of contacts 38 to the common conductor 44.

An insulating disc 52 is positioned in the end of the cylindrical housing member 36 opposite to that engaged by the cover plate 42. This disc may have projections 54 about the periphery thereof which mate with recesses 55 in the member 36 to key the same in position. The disc 52 has a plurality of ridges 56 (FIG. 5) which extend between the individual contact portions 40 to insure that the contacts are insulated from each other. The ridges also provide a recess or well under each contact into which foreign material which may enter the switch, or which is produced by engagement of the contacts, can fall to eliminate the possibility of such material bridging the contacts. Also, the top of the ridge extending between adjacent contacts 40 may be engaged by the contact 50 as it moves from one contact portion 40 to another, and can be molded of material with abrasive therein so that it cleans the engaging surface of the contact 50. It may be desirable to have a smaller number of interengaging projections 54 and recesses 55 than shown, it being only necessary to hold the disc 52 and the housing section 36 in radial alignment so that the ridges 55 are positioned between the individual contact portions 40. The insulating disc 52 has a center opening 57 to receive a hub 51 on the rotary insulating member 49 of rotor structure 48, to hold the rotor structure in axial alignment.

FIG. 5 shows in more detail the construction of the insulating disc 52 and the ridges 56 thereon. The disc has a central hub portion 53, and the ridges 56 extend from this hub to the edge of the disc to engage the insulator 36. Actually the ridges 56 continue to the projections 54 which fit in the recesses 55 in the insulator 36. The space defined by a pair of adjacent ridges, the hub portion 53 and the inside surface of the insulator 36 forms a well under each contact into which foreign material can drop, so that this is removed from the contacts and does not provide a conducting bridge therebetween. As previously stated, the disc 52 may be molded of material having abrasive in the portion thereof forming the ridges, and this acts to clean the surface of contact 50 as this contact slides thereacross. However, this will produce small conducting particles which could form bridges between the contacts 40. FIG. 5 shows the contact 40 and the insulator 36 to show the relative position of the contacts and wells formed by the ridges.

FIG. 6 shows the contact arrangement in more detail, and shows that a number of contacts 50 may be used on the rotor 48. This figure also shows that the common conductor 44 may be replaced by a plurality of flat conductor segments. In the structure shown, six conductor segments 61, 62, 63, 64, 65 and 66 are used in place of the single conductor 44. In this structure, a 24 position switch is illustrated having 24 fixed contacts 40, so that there are four contacts 40 for each conductor segment 61 to 66. Six movable contacts 50 are provided in the rotor, one for each segment 61 to 66. The switch structure therefore provides six separate switching sections, each having four positions in which a different one of the contacts 40 is connected to one of the contact conductor 61 to 66. For such a switch, the stop pins 34 would be positioned to allow the stop arm 30 to move through an angle of 60.degree., and the detent structure 27 would clearly define the four positions in the 60.degree. segment.

It will be apparent that various arrangements of the movable contacts and contact segments can be provided to provide desired switching arrangements. Thus each deck can form a plurality of separate switch sections, and a plurality of decks can be used. The switch contact arrangement is extremely flexible and can provide a large number of simultaneously operated switching section in a very small switch structure.

In the switch structure shown, the movable contact 50 engages a ridge 55 as it moves from one contact portion 40 to another, and breaks the one contact before the next contact is made. It will be apparent that the contact 50 can be constructed so that it will simultaneously engage two contact portions, and the first contact is not broken until after the next contact is made. In such case, the ridges 55 are constructed so that the contact 50 does not engage the tops thereof as it moves from one contact portion 40 to the next.

The switch construction of the invention provides a very compact rotary switch having 16 or more rotary positions. One or more switch decks can be provided to thereby provide a large number of switched connections which can be independent of each other or have any one of a large number of different relations as may be required for different applications.

Claims

1. A rotary multi-position electrical switch structure including in combination,

a molded cylindrical insulating member having a plurality of conductors molded therein, said conductors being substantially uniformly radially spaced about said insulating member and having external terminal portions and internal contact portions,

an insulating plate engaging one end of said cylindrical insulating member, contact means in engagement with said insulating plate,

a rotor structure within said insulating member having a rotary insulating member and at least one conducting contact moved by said member, said contact having portions selectively engaging said contact portions of said conductors and said contact means, and

an insulating disc engaging said cylindrical insulating member at the end thereof opposite to said end engaging said insulating plate, said disc having a portion extending into said cylindrical insulating member and ridges extending between said contact portions, said disc and said cylindrical member having interengaging portions to insure that said disc is in a predetermined radial position with respect to said cylindrical

2. A switch structure in accordance with claim 1 wherein said internal contact portions have raised ends, and said contact of said rotor structure is U-shaped and has a first end adapted to selectively engage said contact portions and a second end adapted to engage said contact

3. A switch structure in accordance with claim 1 wherein said insulating disc extends within said cylindrical insulating member with one surface

4. A switch structure in accordance with claim 1 wherein said ridges of said insulating disc have heights to be engaged by said contact of said rotary member when said contact moves from one of said contact portions to another, and wherein said ridges are constructed of a material which acts

5. A switch structure in accordance with claim 4 wherein said insulating disc has a central hub connected to said ridges and cooperating therewith and with the inside surface of said cylindrical insulating member to form

6. A switch structure in accordance with claim 1 wherein said insulating plate has a plurality of recesses therein and said contact means includes a plurality of flat conductors positioned in said recesses, with each conductor having a radial extent to be aligned with a plurality of said

7. A switch structure in accordance with claim 6 wherein said rotor structure has a plurality of conducting contacts equal in number to the

8. A rotary electrical switch structure including in combination,

a base member having an operating shaft supported thereby and means coupled to said shaft providing predetermined switching positions,

a plurality of switch decks mounted on said base member each including a cylindrical insulating housing section having a plurality of conductors molded therein in radially spaced positions, an insulating disc in predetermined positional engagement with said housing section and having a central opening therein, contact means supported in fixed position with respect to said conductors, and a rotor within said housing section including a movable contact selectively bridging said conductors and said contact means, said rotor including a rotary insulating member having a hub extending into said central opening in said insulating disc, and

drive means coupling said operating shaft to said rotor of each of said

9. A switch structure in accordance with claim 8 wherein said conductors have portions extending outside said cylindrical housing section forming terminals, and portions extending within said housing section forming fixed contacts which are engaged by said movable contact of said rotor.

10. A switch structure in accordance with claim 8 wherein said base member has a plurality of openings therein and including a pair of stop pins adapted to be positioned in said openings, and a stop plate coupled to said operating shaft having a stop arm adapted to engage said stop pins to limit rotation of said operating shaft, with the extent of rotation being

11. A rotary switch structure in accordance with claim 1 wherein said insulating disc has a central opening therein, and said rotary insulating member has a hub extending into said central opening.