US2962571A

US2962571A - Electric switch

Info

Publication number: US2962571A
Application number: US744954A
Authority: US
Inventors: Zanichkowsky Martin
Original assignee: Allied Control Co Inc
Current assignee: Allied Control Co Inc
Priority date: 1958-06-27
Filing date: 1958-06-27
Publication date: 1960-11-29
Anticipated expiration: 1977-11-29

Description

1960 M. ZANICHKOWSKY 2,962,571

ELECTRIC swmca Filed June 27, 1958 Fl G l 32 f 34 q 18 g 21 19 J 22 3 1o 20 3 N 4 l I 33 I 302 35 31 j:] 1 V 15 4 30a 17 go :4 c

INVENTOR. Martin Zanichkowsky ATTORNEY United states Fatefit' ELECTRIC SWITCH Filed June 27, 1958, Set. No. 744,954

3 Claims. (Cl. 200-159) This invention relates to the art of electric switches. The invention pertains, in one of its more specific aspects, to an improved and simplified multi-pole switch which may be made in miniature and sub-miniature sizes.

The design of suitable switches has become very difficult in recent years due to space and weight limitations imposed by use conditions. In many instances, conditions of use are such that less and less space and weight can be allotted to switch components. For example, transistor circuits, aircraft equipment and electric computors, almost invariably require switch accessories, While imposing severe size and weight limitations thereon. In the design of electric switches in which size is a critical factor, it is diflicult to provide suitable actuating means which is capable of assemblyon a production line basis. This, coupled with the requirement that the switches be positive in action and capableof properly controlling electrical energy in considerable quantities,

has severely limited developments in the art of miniature and subminiature switch design.

It is accordingly an important object of this invention to provide an improved electric switch which can be manufactured in miniature and sub-miniature sizes.

Another object of the invention is to provide an electric switch which may be readily and economically assembled.

The invention has for a further object the provision of an electric switch which is adapted to be actuated by a push button unit or a spring-loaded toggle assembly.

A still further object of the invention is to provide a switch of the character indicated that is simple and compact in design, sturdy and durable in construction, reasonable in manufacturing cost and capable of performing its intended functions in a satisfactory and dependable manner.

To the end that the foregoing objects may be attained, an electric switch according to this invention comprises a base and a cover secured to the base. The base is made of a suitable electric insulating material while the cover is preferably made of an appropriate metal. Secured to and projecting outwardly of the base are a plurality of spaced first electrical terminals and a plurality of spaced second electrical terminals, there being provided a first terminal for each second terminal.

Each first terminal is connected to a fixed electrical contact positioned within the housing. The switch includes a plurality of spaced electrically conductive resilient members which are positioned wholly within the housing. Each resilient member is generally C-shaped and comprises a first end part which is secured to a corresponding second terminal, a second end part which serves as a movable contact that is spaced from a corresponding fixed contact, and an elongated substantially rectilinear central part which is intermediate the first and second parts. An insulating plate overlies and bears against the central parts of the resilient members.

The switch includes an actuating means which extends through the cover and is operable from the exterior of the housing. The actuating means engages the insulating plate and is adapted to move the plate and flex the resilient members to effect engagement of each movable contact with a corresponding fixed contact. The actuating means may consist of a push button unit or a springloaded toggle assembly, both of which will be described further along herein.

The switch includes a stop element integral with the base and a shoulder formed in the housing to respectively limit movement of the plate and resilient. members and insure retention of the plate in proper relationship with respect to the resilient members upon operation of the actuating means. The stop element and shoulder are shown in the drawing and their functions will be readily apparent from an examination thereof taken in conjunction with the detailed description that follows.

The enumerated objects and other objects, together with the advantages of this invention will be readily understood by persons skilled in the art from the following description and the accompanying drawing, which, respectively, describe and illustrate switch constructions embodying the invention.

In the drawing, wherein like reference numerals denote corresponding parts in the several views:

Fig. 1 is a view in central vertical cross section of a push button switch constructed in accordance with this invention;

Fig. 2 is a bottom plan view of the switch shown in Fig. 1;

Fig. 3 is a view taken along line 33 of Fig. 1; and

Fig. 4 correspondsto Fig. l and illustrates a modified form of the invention wherein a spring-loaded toggle assembly is utilized to actuate the switch.

'Referring to Figs. 1, 2 and 3, there: is shown a switch comprising a housing 10 which consists of a base 11 and a cover or casing 12. The base is made of a suitable electric insulating material and is formed with an outer annular recess which is defined in part by shoulders 13. The base is provided with an integral upwardly projecting abutment 14 which serves as a stop element for parts that will be described further along herein.

Cover 12 comprises a rectilinear tubular member 15 having a plurality of depending tongues 16. The lower end of tubular member 15 registers with the annular recess of the base and bears against shoulders 13 as illus trated in Fig. 1. When the parts are in. this relative position, tongues 16 are bent inwardly with respect to the bottom of the base, as shown in Fig. 2, to thereby firmly secure the cover to the base. Tubular member 15 is provided with an inner shoulder 17 which extends across one wall thereof, as shown in Pig. 1. The tubular member has a right circular cylindrical tubular extension 18 which is externally threaded, as indicated at 19, to receive nuts (not shown) for securing the switch in a selected position on a panelboard or other support (also not shown). Extension 18 is formed with a relatively large diameter lower passageway 20 and a merging relatively small diameter passageway 21. An annular shoulder 22 is provided at the juncture of these passageways.

A plurality of spaced first electrical terminals 23 is attached to base 11 by electrically conductive rivets 24. Each rivet 24 carries a fixed electrical contact 25 which projects into the interior of the housing. A plurality of spaced second electrical terminals 26 is attached to the base by electrically conductive rivets 27.

The switch includes a plurality of electrically conductive resilient members 35 which are of generally C-shaped configuration. Each member 30 is of one piece construction and comprises a first end part 30a which is fixedly connected to the base by a corresponding rivet 27, a rectilinear central part 30b which is connected to end part 30:: by an arcuate part 300, and a second end part 30d which is connected to the central part 3012 by an arcuate part 302. Members 30 are parallel and their central parts 30b are coplanar and inclined with respect to the base, as shown in Fig. 1. Each end part 30d is normally aligned with, but spaced from, a corresponding contact 25 and serves as a movable contact which is adapted to engage its fixed contact 25 upon predetermined downward flexing of corresponding resilient member 30.

A plate 31 overlies and bears against central parts 30b of the resilient members. This plate is made of a suitable electric insulating material. The length and width of plate member 31 are slightly less than the corresponding internal dimensions of tubular member 15. The lower edge of plate 31, Le. the edge at the right of Fig. 1, projects into the space between the base and shoulder 17. The housing parts and the plate are so arranged that shoulder 17 engages the lower edge portion of the plate to hold the plate against tipping or cocking on an axis passing through the plane of the plate in a direction from right to left, as viewed in Fig. 1.

Positioned above plate member 31 and extending through cover 12 is an actuating means consisting of a push button unit 32. This unit is of one piece construction and is made of a suitable electrical insulating material, preferably an appropriate synthetic resin, such as molded nylon. The push button unit comprises a lower part 33 which registers with passageway 20, and an upper part 34 which registers with passageway 21 and extends upwardly beyond tubular extension 13. Unit 32 has a rounded lower end 35 which bears against the upper surface of plate 31.

It will be noted that the plate is normally free of the housing and is not attached 'to any of the resilient members 30 or to push button unit 32. The plate is restrained against appreciable movement in its own plane due to the proximity of its edges to the inner surfaces of the side walls of the housing. On the other hand, the plate is free to swing downwardly with the resilient members when the push button unit is depressed. Swinging movement of plate 31 and bending movement of resilient members 30 is limited by abutment 14 which is aligned with the axis of the push button unit.

In assemblying the switch, terminals 23 and fixed contacts 25 are attached to the base 11 by rivets 24 and terminals 26 and resilient members 30 are attached to the base by rivets 27. Cover 12 is inverted and push button unit 32 is inserted in tubular extension 18, the unit coming to rest by part 33 bearing against shoulder 22. Insulating plate 31 is then inserted in the open end of tubular member 15 and is supported therein by housing shoulder 17 and rounded end 35 of the push button unit. The base, together with its attachments, is inverted and introduced into the open end of the cover, whereby the cover bears against shoulders 13. The parts are held in this relative position and tongues 16 are bent inwardly to effect firm engagement between the cover and the base. It will be apparent that there are no critical assembly operations which require compex fixtures or highly skilled labor, despite the fact that the switch may be of miniature or subminiature size.

For the purpose of outlining the operation of the switch, it is assumed that the same has been assembled and the parts are in the relative position shown in Fig. 1. This is a normal relative position of the elements. Due to the resilience of members 30, movable contacts 30d are spaced from and out of engagement with corresponding fixed contacts 25 and push button unit 32 is urged to and maintained in its uppermost position relative to the housing. When the push button unit is depressed, i.e. pushed inwardly relative to the housing, it causes insulating plate 31 to swing downwardly thereby effecting direct engagement of movable contacts 30d and fixed contacts 25. As the insulating plate is swung downwardly, it is maintained in the planar relationship with resilient members 30 by virtue of its lower edge engaging shoulder 17. The engagement of the moving contacts with the fixed contacts closes the electric circuits between companion pairs of

terminals

23 and 26. The parts are so constructed and arranged that all movable contacts engage their fixed contacts substantially simultaneously. The resilience of movable contacts 30d permits of slight excess travel at the time of contact with fixed contacts 25. This insures that wiping will occur between contacts and provides electrical efficiency over a long period of time. Damagingly excessive travel of plate 31 and resilient members 30 is prevented by abutment 14 which serves as a stop to limit travel of these parts. This abutment is preferably aligned with the axis of the push button and is so arranged that the parts of the resilient member are not'fiexed beyond their elastic limits for any operation of the switch and regarcl-- less of the pressure which may be applied to the push button unit. By arranging abutment 14 in axial alignment with the push button unit, turning moments are avoided.

Reference is now had to Fig. 4 which illustrates a modification of the invention that is basically the same as that of Figs. 1, 2 and 3. The principal difference in the construction shown in Fig. 4 over that of the earlier described form of the invention is in the utilization of a spring-loaded toggle assembly in place of a push button unit. The switch of Fig. 4 includes a cover or casing 36 which comprises a tubular member 37 that registers with recesses in base 11 and is secured to the base by tongues 16. Tubular member 37 is recessed to form a shoulder 38, corresponding to shoulder 17 of Fig. 1. The cover has a tubular extension 40 which is externally threaded as indicated at 41. The extension has an upper passageway which is defined in part by convergent surfaces 42 and a merging lower passageway which is defined in part by a rounded surface 43.

The spring-loaded toggle assembly of this modification is generally denoted by numeral 44 and includesa tubular handle 45 having an enlarged lower portion 46 for contact with rounded surface 43 of the tubular extension. Handle 45 carries a cap which consists of a spherical finger grip 48 and a threaded extension 49 whichengages a tap in the upper end of the.handle. A solid rod 50 is slidable in handle 45 and has a spherical head 51 afiixed to its lower end. Rod 50 is preferably made of a suitable metal, such as that available under the trademark Kovar. Head 51 is made of glass or other appropriate wear-resistant electrical insulating material which is fused to the lower end of the rod.

The illustrated construction includes spring means for normally and yieldingly urging rod 50 and its head 51 downwardly against insulating plate 31. This spring means preferably consists of a helical compression spring 52 which is positioned within handle 45 and bears at its ends against the upper end of rod 50 and the lower end of extension 49. Grip 48 and its extension 49 serve as a means for adjusting the loading on spring 52. A relatively thin pin 53 is positioned within the confines of spring 52. This pin is in the nature of a floating pin in that it is shorter than the distance between the lower end of extension 49 and the upper end of rod 50. This pin prevents damage to the spring and eliminates the possibility of the spring acquiring a permanent set in use. The construction and operation of toggle assembly are described in greater detail in pending application of M. Zanichkowsky et al., Serial No. 712,971, entitled Toggle Switch, to which reference may be had.

The switch of Fig. 4 is. shown with its parts in normal open position. To close the switch, handle 45 is swung to the right, as viewed in Fig. 4. This causes rod 50 and its spherical head 51 to ride to the left. The force of spring 52 is superior to that of resilient members 30 and the toggle assembly thereby causes plate 31 and the resilient members to swing downwardly eifecting engagement between movable contacts 30d and corresponding fixed contacts 25. The right hand edge of plate 31 engages shoulder 38 when the switch is in closed position and prevents damage to the ends of the resilient memhere. As in the case of the earlier described construction, abutment 14 serves as a stop and additionally serves as a fulcrum in actuating plate 31 to effect closing of the switch.

While the invention has been herein described in its preferred embodiments, it will be understood that it may take other forms in practice. Thus, for example, the switch may be provided with two or four or more sets of contacts, instead of three sets as shown in the drawings. Other modifications of the invention will be apparent to those skilled in the art and the invention is not to be restricted to the illustrated constructions, except as limited by the appended claims.

I claim:

1. In an electric switch, a housing comprising a base and a cover secured to the base, a plurality of spaced fixed electrical contacts carried by the base, a plurality of spaced electrically conductive resilient members positioned wholly within the housing, each resilient member being generally C-shaped and comprising a first end part, a second end part and an elongated substantially rectilinear central part, each of said first end parts being fixedly secured to the base, each of said second end parts constituting a movable electrical contact that is spaced from a corresponding fixed electrical contact, said central parts being substantially parallel and coplanar and inclined with respect to the base, an insulating plate overlying and bearing against the resilient members and being substantially coextensive with the central parts thereof, actuating means extending through the cover and operable from the exterior of the housing, said actuating means engaging the insulating plate and being adapted to move the same and flex the resilient members to effect engagement of each movable contact with a corresponding fixed contact, and a shoulder formed in the housing for engagement by the edge portion of the plate adjacent the first parts of the resilient members to hold the plate and the central parts of the resilient members in coplanar relationship upon operation of the actuating means.

2. An electric switch according to claim 1 wherein the actuating means comprises a push button. unit, the switch also including a stop element carried by the base and projecting toward the surfaces of the central parts of the resilient members remote from the plate, said stop element being aligned with the push button unit and limiting fiexture of the resilient members in response to operation of the push button unit.

3. In an electric switch, a housing comprising a base and a cover secured to the base, a plurality of spaced fixed electrical contacts carried by the base, a plurality of spaced electrically conductive resilient members positioned wholly within the housing, each resilient member comprising an arcuate first end part, a second end part and an elongated substantially rectilinear central part, each of said first end parts being fixedly secured to the base, each of said second end parts constituting a movable electrical contact that is spaced from a corresponding fixed electrical contact, said central parts being substantially parallel and coplanar and inclined with respect to the base, an insulating plate overlying and bearing against the resilient members and being substantially coextensive with the central parts thereof, actuating means extending through the cover and operable from the exterior of the housing, said actuating means engaging the insulating plate and being adapted to move the same and flex the resilient members to eifect engagement of each movable contact with a corresponding fixed contact, and a shoulder formed in the housing for engagement by the edge portion of the plate adjacent the first parts of the resilient members to hold the plate and the central parts of the resilient members in coplanar relationship upon operation of the actuating means.

References Cited in the file of this patent UNITED STATES PATENTS 2,457,153 Hubbell Dec. 28, 1948