US3073935A

US3073935A - Electrical switches

Info

Publication number: US3073935A
Application number: US102165A
Authority: US
Inventors: Teddy F Smusz
Original assignee: Royal Mcbee Corp
Current assignee: Royal Mcbee Corp
Priority date: 1961-04-11
Filing date: 1961-04-11
Publication date: 1963-01-15
Anticipated expiration: 1980-01-15

Description

Jan. 15, 1963 T. F. SMUSZ 3,073,935

ELECTRICAL SWITCHES 2 Sheets-Sheet 1 Filed April 11, 1961 Figl 22 INVENTOR TEDDY E iMS BY MAJ Jan. 15, 1963 1'. F. SMUSZ ELECTRICAL SWITCHES 2 Sheets-Sheet 2 Filed April 11, 1961 Fig.6

Fig.5

INVENTOR TEDDY F SMUSZ 7 Arron'm s Mm A atent 3,073,935 Patented Jan. 15, 1963 Free 3,073,935 ELECTRICAL SWITCHES Teddy F. Smusz, Bristol, Conm, assignor to Royal McBee Corporation, a corporation of New York Filed Apr. 11, 1961, Ser. No. 102,165 3 Claims. (Cl. 200-460) This invention relates to electrical switches; more particularly it relates to push button switches characterized by wedge shaped contact elements to achieve high contact pressures with minimum depressive forces.

It is an object of the invention to provide a reliable electrical keying device.

Another object of the invention is in the provision of an electrical keying device having a contact element operable to provide high contact pressure with a light depressive force.

Another object of the invention is in the provision of a reliable electrical keying device 'of the push to make, release to break type employing a wedge type contact element.

A further object of the invention is in the provision of a reliable electrical keying device of the make-break type employing a wedge type contact element.

A still further object of the invention is to provide a reliable electrical keying device employing a wedge type contact element which isself adjusting to compensate for contact wear.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following fully depressed position of the switch;

FIGURE 4 is a side view of a push to make and break switch in its normal position;

FIGURES 5, 6 and 7 are front views of the switch shown in FIGURE 4 illustrating an intermediate position,

the make position and the position after a make respectively.

FIGURE 8 is an enlarged section view showing the contact mounting structure of the FIGURE 4 contact element.

Referring now to the drawings there is shown in FIGURE 1 a rectangular body 12 formed from insulating material having a peripheral flange 13 and flexible detents 14 depending from the flange on opposite sides of the body. The body is provided with spaced slots 15 adapted to receive the upper ends 16 of stationary contacts 17 as by a press fit. The body is also provided with a central slot 18 adapted to guide a plunger 19. The plunger is provided with a finger button 22 secured thereto as by a press fit, and is formed below the finger button with two

shoulders

23 and 24 respectively, the lower one of which is adapted in cooperation with a central abutment 25 of the body to limit the downward movement of the plunger, and the upper one of which is adapted to maintain the upper end of a plunger return spring 26. The lower end of the spring 26 is supported by and insulated from the contact ends 16 extending through the body by an insulating washer 27 located and maintained by the central abutment.

As shown in FIGURE 1 the lower end 28 of the plunger is reduced in its width and extends freely through come shaped contact 36 a circuit is made.

a contact element generally designated by reference numeral 32 which is urged toward a stop washer 33 at the lower extremity of the plunger by a spring 34 mounted about the plunger between the shoulder 35 formed by the reduced width of the plunger and the contact element 32. The contact element 32 comprises an inverted truncated cone 36 whose base diameter is greater than the spacing between stationary contacts 17; the latter being provided with rectangular cutouts 37 to permit movement of the contact element 32 under the action of

springs

26 and 34 as will hereinafter more clearly appear. Secured to the lower side of the contact element is a truncated cone 38 of insulating material whose base side is opposite that of the contact element. The base of the cone is formed with a flange 41 which in the normal position of the switch abuts the lower edge 42 of the contacts 17. As shown in FIGURE 1 the stationary contacts 17 may be provided with tabs 43 to facilitate the connection of leads whereby when the stationary contacts are bridged by th As illustrated most clearly in FIGURES 2 and 3 the lower edges 44 of the cutouts 37 in the stationary contacts 17 are bent outwardly thereby conforming to the angle of the cone shaped contact 36 to provide a reliable contact area in the nature of a sliding or wiping contact and to minimize wear.

As heretofore stated FIGURE 1 shows the normal position of the switch in which spring 26 is only slightly compressed and spring 34 is relaxed. Depression of the plunger against the compressive force of spring 26 exerts force on spring 34 which in turn transmits the force to the contact element 32 whereby the plunger 19, spring 34, and contact element 32 all move to the position shown in FIGURE 2 without any changes in their relative positions; the compression of spring 34 being negligible. Upon further depression of the plunger the contact 36 encounters the edges 44 presented by the stationary contacts 17, spring 34 compresses thereby exerting force on the contact element which wedges between the stationary contacts 17. The wedging effect produces components of force tending to spread the stationary contacts which forces are greater than the downwardly exerted force of the plunger 19 thereby giving a high contact pressure make. Upon release of the plunger 19, spring 26 acts to return the parts to the positions shown in FIGURE 1; the stop 33 carrying the contact element 32 upwardly and also limiting the upward motion of the plunger 19.

Referring now to FIGURES 4-8 there is shown a make-break or impulse switch embodying the inventive concept. In this embodiment the cutouts 37 in the stationary contacts 17 are enlarged in a vertical and horizontal direction in order to provide supporting shoulders 51 for a permanent magnet assembly generally designated by reference numeral 52 (see FIGURE 8) comprising rings 53 of insulating material tightly embracing a disc shaped permanent magnet 54 for electrically isolating the permanent magnet from the stationary contacts 17. The magnet 54 is provided with a central bore 55 through which the plunger 19 and a spring 34, corresponding to spring 34 of the FIGURE 1 embodiment, freely pass.

The movable contact element of this embodiment is also an inverted truncated cone 56 and as shown in FIGURE 8 is coaxially mounted on and for movement relative to a tubular sleeve 57 whose inside diameter is large enough to permit the plunger 19 to move freely therein. The sleeve 57 is provided with an outer annular shoulder 58 which fits into a cavity 62 of larger diameter and coaxially of the bore of the contact element 56 whereby when spring 34' urges the sleeve 57 downwardly upon depression of the plunger 19, contact element 56 will be urged downwardly. As shown in FIGURES 4-8 the lower extremities of the stationary contacts 17 are provided with openings 63 adapted to receive as by a press fit laterally extending projections 64 of an insulating member 65 whereby they are maintained in parallel spaced relationship by the insulating member. As shown in FIGURE 8 the insulating member 65 is provided with a central boss 66 on its upper surface. The boss and the insulating member are centrally bored; the latter only partly through its thickness dimension. The opening thus formed in the insulating member guidingly receives the sleeve 57 and the bottom 67 thereof serves to limit its downward motion. A spring 68 is mounted about the sleeve and maintained coaxially of the sleeve by the outer surface of the insulating boss 66; the upper end of the spring 68 abutting the lower surface of the contact element, and the lower end abutting the upper surface of the insulating member 65.

As heretofore stated FIGURE 4 shows the normal inoperative position of the switch wherein spring 26 is only slightly compressed, and

springs

34 and 68 are relaxed. FIGURE 5 shows the plunger 19 partly depressed with

springs

26 and 34 compressing. When the compressive force exerted by spring 34 on the sleeve exceeds the holding force exerted by the permanent magnet 54 on the contact element 56 it will propel the sleeve 57 and contact element 56 downwardly compressing spring 68. Since the contact element is movable relative to the sleeve 5-7, when the latter bottoms in the insulating member the motion of the contact element 56 will continue, further compressing spring 68 until the contact element 56 bridges the edges 44 of the stationary contacts 17. This is the position of the elements illustrated in FIGURE 6, the plunger also having reached the limit of its downward movement. Immediately after the contact element bridges the stationary contacts spring 68 forces the contact element out of engagement with stationary contacts 17 to the position shown in FIGURE 7, its upward motion being terminated by the annular shoulder 58 of the sleeve 57. Upon release of the plunger 19 spring 26 returns it to normal and spring 68 drives the contact element 56 and sleeve 57 upwardly into the zone of influence of the magnet 54 whereupon magnetic force returns the contact element and sleeve to the normal position of FIGURE 4; the return movement of the plunger removing the influence of spring 34 on the sleeve 57 to permit its upward motion under the influence of the magnet.

It should be understood that the foregoing disclosure relates to only a preferred embodiment of the invention and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.

The invention claimed is: i

1. An electrical impulse switch comprising an insulating support, spaced contacts secured to said support, a plunger mounted for movement relative to said support and between said spaced contacts, an inverted truncated cone shaped contact element movable relative to and guided by said plunger, a spring mounted on said plunger for transmitting the motion of said plunger to said movable contact element, a permanent magnet for releasably holding said movable contact element, said magnetic holding force opposing the compressive force stored in said spring during an initial depression of said plunger, said magnetic means releasing said movable contact when said compressive force resulting from further depression of said plunger exceeds said magnetic force whereby said compressive force propels said movable contact element between said spaced contacts, and spring means compressible by said propelled contact element for driving said contact element out of engagement with said spaced contacts immediately after engagement therewith and while said plunger is fully depressed.

2. An electrical impulse switch comprising an insulating support, spaced contacts secured to said support, a plunger mounted for movement relative to and between said spaced contacts, a magnet insulatedly secured between said spaced contacts, an inverted truncated cone shaped contact movable relative to and guided by said plunger, said magnet releasably holding said cone shaped contact against movement, a spring secured to said plunger and bearing on said cone shaped contact adapted to transmit the motion of said plunger to said cone shaped contact, means for depressing said plunger, said magnet restraining movement of said contact by said spring until the energy stored thereby during depression of said plunger overcomes said restraining force and propels said contact between said spaced contacts, a second spring, said driven contact compressing said second spring whereby the compressive force stored therein immediately breaks contact between said cone shaped and said spaced contacts while said plunger is fully depressed, said second spring returning said cone shaped contact into holding contact with said magnet upon return of said plunger to normal position.

3. A momentary contact switch comprising an insulating support, spaced contacts secured to said support adapted to be momentarily bridged, a plunger mounted for movement relative to said support and between said spaced contacts, said plunger being positionable from a normal to a fully depressed condition, a contact element movable relative to said plunger and adapted to momentarily bridge said spaced contacts, a motion transmitting spring mounted on said plunger for transmitting the motion of said plunger to said contact element, permanent magnet means secured to said spaced contacts for releasably holding said contact element until the force stored in said spring overcomes said magnet holding force and propels said contact element into contact with said spaced contacts, and second spring means mounted on said plunger interposed in the path of said propelled contact element whereby the energy stored therein is operative in opposition to the force of said motion transmitting spring to immediately break contact between said contact element and spaced contacts while said plunger is in its fully depressed condition, said second spring restoring said contact element into holding contact with said magnet upon return of said plunger to normal position.

References Cited in the file of this patent UNITED STATES PATENTS 983,976 Carpenter Feb. 14, 1911 1,861,400 Miller May 31, 1932 2,605,375 Ellithorpe July 29, 1952

Claims

1. AN ELECTRICAL IMPULSE SWITCH COMPRISING AN INSULATING SUPPORT, SPACED CONTACTS SECURED TO SAID SUPPORT, A PLUNGER MOUNTED FOR MOVEMENT RELATIVE TO SAID SUPPORT AND BETWEEN SAID SPACED CONTACTS, AN INVERTED TRUNCATED CONE SHAPED CONTACT ELEMENT, MOVABLE RELATIVE TO AND GUIDED BY SAID PLUNGER, A SPRING MOUNTED ON SAID PLUNGER FOR TRANSMITTING THE MOTION OF SAID PLUNGER TO SAID MOVABLE CONTACT ELEMENT, A PERMANENT MAGNET FOR RELEASABLY HOLDING SAID MOVABLE CONTACT ELEMENT, SAID MAGNETIC HOLDING FORCE OPPOSING THE COMPRESSIVE FORCE STORED IN SAID SPRING DURING AN INITIAL DEPRESSION OF SAID PLUNGER, SAID MAGNETIC MEANS RELEASING SAID MOVABLE CONTACT WHEN SAID COMPRESSIVE FORCE RESULTING FROM FURTHER DEPRESSION OF SAID PLUNGER EXCEEDS SAID MAGNETIC FORCE WHEREBY SAID COMPRESSIVE FORCE PROPELS SAID MOVABLE CONTACT ELEMENT BETWEEN SAID SPACED CONTACTS, AND SPRING MEANS COMPRESSIBLE BY SAID PROPELLED CONTACT ELEMENT FOR DRIVING SAID CONTACT ELEMENT OUT OF ENGAGEMENT WITH SAID SPACED CONTACTS IMMEDIATELY AFTER ENGAGEMENT THEREWITH AND WHILE SAID PLUNGER IS FULLY DEPRESSED.