US3301971A

US3301971A - Electric switch with improved disk and contact structure

Info

Publication number: US3301971A
Application number: US468366A
Authority: US
Inventors: David W Johnson
Original assignee: Arrow Hart & Higeman Electric
Current assignee: Arrow Hart & Higeman Electric; Arrow-Hart & Higeman Electric Co
Priority date: 1965-06-30
Filing date: 1965-06-30
Publication date: 1967-01-31
Anticipated expiration: 1984-01-31
Also published as: GB1133935A

Description

I Jan. 31, 1957' D. W. JOHNSON ELECTRIC SWITCH WITH IMPROVED DISK AND CONTACT STRUCTURE Filed June 30, 1965 F/GZ INVENTOR.

00 W0 M/ Johnson BY MS af/omeys ALMMMWK 2 Sheets-Sheet l ELECTRIC SWITCH WITH IMPROVED DISK AND CONTACT STRUCTURE Filed J1me 30, 1965 Jan. 31, 1967 n. w. JOHNSON 2 Sheets-Sheet INVENTOR. Dav/c7 W Johnson BY h/s af/omeys United States Patent C) 3,301,971 ELECTRIC SWITCH WITH IMPROVED DISK AND CONTACT STRUCTURE David W. Johnson, Newington, Conn., assignor to The Arrow-Hart & Higeman Electric Company, Hartford, Conn., a corporation of Connecticut Filed June 30, 1965, Ser. No. 468,366 16 Claims. (Cl. 20011) This invention relates to electric switches and in particular to a rotary, multi-position switch suitable for use with a printed circuit.

Printed circuits are used in increasing numbers. Conventionally such circuits comprise conducting areas pr nted on one side of a flat panel or board. In many applications rotary switches capable of being manipulated to connect a primary terminal to any one of two or more secondary terminals must be employed with or 1n such circuits. Often these switches must be mounted on the panel, with terminal posts extending through the switch housing to be attached to or connected with the conductive areas. As well as being capable of fitting snugly against the panel, such switches must be easy to manipulate, light in weight and in many cases of a construction highly resistant to vibration.

It is an object of the present invention to provide a rotary switch suitable for use with printed circuits.

It is another object of the invention to provide a rotary switch capable of being securely attached to a flat panel and conveniently connected in a printed circuit on the panel.

It is another object of the invention to provide a rotary switch which will be light and easy to manipulate.

It is another object of the invention to provide a rotary switch which is resistant to vibration.

Other objects will become apparent from a consideration of the following specification and claims.

In accordance with the invention the objects enumerated and others, are attained by means of a rotary switch comprising a base, a handle rotatable with respect to said base, a primary fixed contact, a plurality of secondary fixed contacts in said base, each of said fixed contacts having a substantially disc shaped contacting element, a movable contact assembly, rotatable in said base and comprising an arcuate bifurcate section engaging the disc element of the primary fixed contact and a bifurcate finger adapted to engage the disc shaped contacting elements of the secondary fixed contacts, and means connecting said movable contact means with said handle whereby rotation of the handle causes rotation of the movable contact means.

The invention will be further described with reference to the drawings in which:

FIG. 1 is a view, partly in side elevation and partly in vertical section, of a switch made in accordance with the invention, showing the handle and base of the switch.

FIG. 2 is a plan view of the switch of FIG. '1 with the handle removed.

FIG. 3 is a bottom plan view of the handle of the switch of FIG. 1 showing the internal structure of the handle.

FIG. 4 is a plan view of the base of the switch of FIG. 1 with certain movable elements removed.

FIG. 5 is a plan view of a movable contact as used in the switch of FIG. 1.

FIG. 6 is an end view of the movable contact of FIG. 5.

FIG. 7 is a perspective view of a drive member for use in the switch of FIG. 1.

Referring to the drawings, a switch 9 in accordance wit-h the invention comprises a base 10, which may be of cylindrical shape, and a handle 8. The base 10 has a bottom wall 11 and a circular side wall 12. Conveniently it may be molded from a synthetic resin.

bottom 11 are located a primary fixed contact 13 and Secured to the ice three secondary

fixed contacts

14, 15 and 16. In FIG. 1, for clarity, the upper portion of the contact 14 has been omitted. These contacts are alike and the base 10 may be molded around them, as in the embodiment shown in the drawing, or they may be fixed in the base in any other convenient way. The primary fixed contact 13 is made in one piece and has a terminal post 17 at its outer end, which post extends outside the bottom 11 of the base. Similarly terminal posts 18 and 19 form parts of

secondary contacts

14 and 15, respectively. (The terminal post for secondary contact 16 is not shown.)

The inner end of the contact 13 terminates in a substantially disc-like or planar contacting portion 21 centrally supported by an axial portion 22. The disc-like element 21 is preferably gently bevelled, on both upper and lower surfaces for reasons to be described.

The secondary contacts 1416 are likewise provided with disc shaped

contacting elements

23, 24 and 25.

All of the fixed contacts are secured in position in the base 10 by means of inner disc-like flanges such as 26 and 27, and outer retaining projections such as 28 and 29, shown in FIG. 1 for

contacts

13 and 15. The inner flanges have their flat

outer surfaces

30, 31 abutting the inner surface of the bottom 11 of the base 10 while their

inner surfaces

32, 33 are bevelled in a manner complementary to the surfaces of the

corresponding disc elements

21 and 24. The outer projections such as 28 and 29 are luglike projections which may be forced down in a well such as 34, provided in the outer surface of the base end wall 11.

As shown most clearly in FIG. 4, the internal structure a of the base 10 comprises a central hub 35 having an aperture 36 and a ring 37 concentric with the hub 35. The space between the ring 37 and the hub 35 forms an annular channel 38. A strut 39 joins the ring 37 and the hub 35 and blocks the channel 38 at a point which is opposite the primary fixed contact 13.

'- images of one another.

1 side and a Referring again to FIGS. 1, 2, 5 and 6, a laminated movable cont-act assembly 40 is disposed in the switch abutting the hub 35. This assembly comprises two

movable contact elements

41 and 42 which are mirror As shown in FIGS. 5 and 6 the element 41 is a highly conductive spring of thin sheet metal, such as a beryllium-copper alloy. It has an annular central part 43 with an aperture 44. An arcuate segment 45 extends radially from the part 43 on one finger 46 extends radially from the opposite side. Two

positioning tabs

47 and 48 extend radially from opposite sides of the part 43 intermediate the arcuate section 45 and the finger 46.

As shown in FIG. 6 the

corners

72 and 73 of the finger are bent up. Similarly the

corners

49 and 50 of the arcuate section 45 are bent up.

Corresponding corners on the other lamination of the movable contact 42 are bent down. The complementary oppositely bent corners of the fingers 46, 46a receive the bevelled surfaces of the disc-

like elements

23, 24,

- receives fingers 46 and 46a of the movable contact assem 25 of the

fixed contacts

14, 15 and 16. Similarly the bent up corners of the

arcuate section

45, 45a receive the disc-like section 21 of the primary fixed contact 13. I To position and move the movable contact assembly 40 in the switch there is provided a drive, member 51. As will appear from FIG. 7 the drive member 51 is a hollow cylindrical body made of a tough insulating material such as nylon having a drive section 52 and a positioning section 53. The drive section 52 has exterior longitudinal fiuting 54. The positioning section is a sleeve having a cut out section 55, and three

longitudinal slots

56, 57 and 58. The positioning section is dimensioned to fit in the channel 38 of the base 10 with the strut 39 in the cut out section 55. In this position the slot 56 bly 40 and the

slots

57 and 58 receive positioning tabs a 47 and 48 of element 41 and shown) of element 42.

the corresponding tabs (not Two

leaf springs

59 and 60, in the shape of a lazy W are seated in

slots

63, 64, 65 and 66 in the cylindrical wall 12 of the base 10, so that the central vertices 61, 62 I of the Ws engage the fiuting of the drive member and which is shaped to receive the fluted section 52 of the drive member 51. As shown in FIG. 1, the handle is slipped over the drive member and retained in that position by a screw 68 which passes through the aperture 36 in the base, through the central apertures of the

contact elements

41 and 42, through the center of the drivemember 51 and is threaded into a tapped socket 69 in handle 8. The handle 8 is provided with a shoulder 70 about its periphery, and the screw 68 holds the handle 8,. against the action of a helical spring 71 seated internally of the drive member 51, in a position such that the shoulder 70 of the handle engages the circular wall 12 of the base 10.

The operation of the device will be obvious. Turning the handle 8 turns the drive member 51 by virtue of the engagement of the fiutings in that member with the socket 67 in the handle. As the drive member turns it cams the

leaf springs

59 and 60 so that the apexes of the Ws are forced out of one fluting and into another.

The drive member also causes the bifurcate movable contact member 40 to be turned. The fingers 46 and 46a of the

individual elements

41 and 42 thus slip from the disc element of one fixed contact to the next. At the same time the

arcuate members

45 and 45a slide across the disc element 21 of the primary fixed contact 13 never breaking contact therewith. Thus a circuit may be established from the primary fixed contact 21 through the movable contact assembly 40 to one of the secondary fixed contacts.

It will be observed from the drawings that the dimensioning of the drive member 51 and the location of the

movable contacts

14, 15 and 16 are such that when the

springs

59 and 60 are seated in a fluting of the drive member, the finger of the movable contact engages one of the secondary contacts. An indexing mark (not shown) may be applied to the top of the handle 8, in line with one of the flutings in the socket 67. When the handle is assembled with such mark directly over the finger 46 of the movable contact assembly, the index mark will indicate with which fixed contact the movable contact assembly is engaged. The springs 59 and "60* enter into the indexing or indicating operation by their cooperation with the fluting of the drive member 51 to insure stepwise movement of said drive member and movable contact assembly, so that when the movable contact assembly is at rest it will always engage one of the fixed

contacts

14, 15 or 16. In this connection it will be noted that the cut out section 55 on the positioning section of drive member 51 permits the drive member only a limited angular movement which is keyed to the arcuate distance between

contacts

14 and 16. Further movement is prevented by the sides of cut out section 55 coming up against the strut 39 in the base Thus it will be seen that the present invention provides a simple multi-position rotary switch readily adaptable to mounting on a flat surface. Terminal posts 17, 18, 19 and 21? extending from the base of the switch may be connected to printed circuits. The action of the switch itself is positive. Becausecontact is made by a bifurcate movable contact member having elements on both sides of the fixed contact members, and because the helical spring 71 maintains pressure on the movable contact vibration has a minimal effect. All parts except the contacts and the springs may be molded from synthetic resins with the advantages of light weight and low cost.

It will be obvious that various changes may be made in the structure specifically shown and described herein without departing from the scope of the invention. In particular it may be pointed out that any number of secondary fixed contacts may be used.

What is claimed is:

1. A rotary switch comprising:

a cylindrical base having a bottom and a side wall, said bottom having a central hub, a ring about said hub, said ring and said hub defining an annular channel and a strut extending across said channel from said ring to said hub;

a primary fixed contact in said base and a plurality of secondary fixed contacts in said base, each of said fixed contacts having a disc shaped contacting element;

a movable contact assembly comprising a bifurcate arcuate section for engaging the disc shaped element of the primary fixed contact and a bifurcate finger for engaging the disc-like members of the secondary contacts;

a hollow cylindrical drive member having a fluted section and a positioning section, said positioning section fitting in the annular channel of said base and having means engaging the movable contact assembly whereby rotation of said drive member causes rotation of the contact assembly;

a leaf spring seated in said :base and engaging the fiuting of the drive member to provide indexing when said drive member is rotated;

a handle having a socket engaging the fluted section of the drive member, whereby turning said handle turns said drive member;

a helical spring in said hollow drive member pressing upon said movable contact assembly; and

a bolt passing through the hub of said base and threaded in said handle to hold said handle to said base against the action of said helical spring.

2.'The rotary switch claimed in claim 1, wherein the drive member has a cut out section fitting over the strut extending across the annular channel in the bottom of the switch, contact between the sides of said cut out section and the strut limiting rotational movement of the drive member. I

3. The rotary switch claimed in claim 1 wherein said movable contact assembly comprises two contact elements, placed face to face, each having an arcuate section at one end and .a finger at the other, the corners ofthe arcuate sections and of the fingers being bent to form entrances.

4. The rotary switch claimed in claim 1 wherein the movable contact assembly has positioning tabs and the drive member has cut out sections for receiving said tabs.

5. The rotary switch claimed in claim 1 in which there are two leaf springs located on opposite sides of the drive members, said springs being in the form of a lazy W, the central apexes of the springs engaging the flutings of the drive member.

6. The rotary switch claimed in claim 5 and comprising slots in the side wall of the casing for seating said springs.

7. The rotary switch claimed in claim 1 wherein the fixed contacts each comprises a terminal post extending through the bottom of the base.

8. The rotary switch claimed in claim 1 wherein the fixed contacts eaoh comprise an inner disc-shaped retaining member abutting the bottom of the base.

9. The rotary switch claimed in claim 8 wherein the upper and lower surfaces of the disc-shaped contacting elements of the fixed contacts are bevelled and the upper surface of the inner retaining member is bevelled in a manner complementary to the bevelling of the lower surface of the corresponding disc-shaped contacting element. I i

10. A rotary switch comprising a base, a primary fixed contact in said base, a plurality of secondary fixed contacts in said base, each of said primary and secondary fixed contacts being electrically and structurally inde pendent and each having at least one side thereof bevelled, a rotatable resilient contacting assembly in said base for electrically connecting, selectively, said primary fixed conta-cts to said secondary fixed contacts, a handle rotatable with respect to said base, and drive means engaging said contacting assembly and said handle whereby, rotation of said handle causing rotation of said drive means and said contacting assembly to efiect pure sliding contact between said contacting assembly and said fixed contacts.

11. The switch claimed in claim 10 and comprising means in said base, engaging said drive means, for limiting the rotation of said handle.

12. The switch claimed in claim 10 wherein the drive means comprises a tubular member having a fluted section on one end and wherein said handle has an internally fluted socket for engaging said fluted section of said drive means. a

13. The switch claimed in claim 12 and including spring means seated in said base and engaging the fluted section of said drive means to insure stepwise movement of said drive means.

14. A rotary switch comprising .a base, a handle rotatable with respect to said base, a primary fixed contact in said base, a plurality of secondary fixed contacts in said base, each of said fixed contacts having a disc-shaped contacting element including opposed first and second sides, a movable contact assembly rotatable in said base and comprising a resilient arcuate bifurcate section engaging the first and second sides of the primary fixed contact and a resilient bifurcate finger adapted to engage the first and second sides of the secondary fixed contacts and means connecting said movable contact assembly with said handle whereby rotation of said handle causes rotation of the movable contact assembly.

15. The switch claimed in claim 14 wherein the movable contact assembly comprises two laminations each comprising a center part, an arcuate section extending on one side thereof and a finger extending on the opposite side thereof, the corners of said arcuate section and the corners of the fingers being flared forming entrances for the fixed contacts.

16. The switch claimed in claim 15 wherein the means connecting the movable contact assembly comprises a tubular drive member having cut out sections on one end thereof and wherein the mowable contact elements have positioning tabs engaging said out out sections.

References Cited by the Examiner UNITED STATES PATENTS 2,693,573 11/1954 Perkins 20011 X 2,694,756 11/1954 Warnke 200-166 X 2,726,876 9/1956 Glogau et al 20011 3,135,840 6/1964 Ausfeld 200-11 X ROBERT K. SCHA'EFER, Primary Examiner. J. R. SCOTT, Assistant Examiner.

Claims

1. A ROTARY SWITCH COMPRISING: A CYLINDRICAL BASE HAVING A BOTTOM AND A SIDE WALL, SAID BOTTOM HAVING A CENTRAL HUB, A RING ABOUT SAID HUB, SAID RING AND SAID HUB DEFINING AN ANNULAR CHANNEL AND A STRUT EXTENDING ACROSS SAID CHANNEL FROM SAID RING TO SAID HUB; A PRIMARY FIXED CONTACT IN SAID BASE AND A PLURALITY OF SECONDARY FIXED CONTACTS IN SAID BASE, EACH OF SAID FIXED CONTACTS HAVING A DISC SHAPED CONTACTING ELEMENT; A MOVABLE CONTACT ASSEMBLY COMPRISING A BIFURCATE ARCUATE SECTION FOR ENGAGING THE DISC SHAPED ELEMENT OF THE PRIMARY FIXED CONTACT AND A BIFURCATE FINGER FOR ENGAGING THE DISC-LIKE MEMBERS OF THE SECONDARY CONTACTS; A HOLLOW CYLINDRICAL DRIVE MEMBER HAVING A FLUTED SECTION AND A POSITIONING SECTION, SAID POSITIONING SECTION FITTING IN THE ANNULAR CHANNEL OF SAID BASE AND HAVING MEANS ENGAGING THE MOVABLE CONTACT ASSEMBLY WHEREBY ROTATION OF SAID DRIVE MEMBER CAUSES ROTATION OF THE CONTACT ASSEMBLY; A LEAF SPRING SEATED IN SAID BASE AND ENGAGING THE FLUTING OF THE DRIVE MEMBER TO PROVIDE INDEXING WHEN SAID DRIVE MEMBER IS ROTATED; A HANDLE HAVING A SOCKET ENGAGING THE FLUTED SECTION OF THE DRIVE MEMBER, WHEREBY TURNING SAID HANDLE TURNS SAID DRIVE MEMBER; A HELICAL SPRING IN SAID HOLLOW DRIVE MEMBER PRESSING UPON SAID MOVABLE CONTACT ASSEMBLY; AND A BOLT PASSING THROUGH THE HUB OF SAID BASE AND THREADED IN SAID HANDLE TO HOLD SAID HANDLE TO SAID BASE AGAINST THE ACTION OF SAID HELICAL SPRING.