US2530364A - Electrical switch - Google Patents

Description

NV 14, 1950 c. A. wooDwARD 2,530,364

ELECTRICAL SWITCH Filed Jan-` 14, 1949 lllllllllllll '11114 rlllllllllllllll 'a I6 I8 lo ATTOR NEY.

Patented Nov. 14, 17950 ELECTRICAL SWITCH Clement A. Woodward, Wellesley, Mass., assignor to United-Carr Fastener Corporation, Cambridge, Mass., a corporation of Massachusetts Application January 14, 1949, Serial No. 70,890

2 Claims.

This invention relates generally to electrical switches, and has particular reference to a switch adapted to be operated by a closure member such as an automobile door.

Plunger operated electrical switches are frequently provided in door frame moldings in automobiles to turn on and oif an internal light when the door is opened` and closed. The switch is usually mounted behind the molding and is provided with a spring mounted operating plunger, which is extended when the door is open and forced inwardly when the door is closed.

Although switches used for such installations are generally satisfactory in operation when rst installed, it has been found that after prolonged use, the plunger operating spring becomes too weak to effect good electrical contact between the switch contact elements. Consequently, only a slight force on the plunger is necessary to break the electrical Contact in the switch and in many cases, even slight vibrations imparted to the switch causes undesirable flickering of the light.

-The object of the invention is to provide a plunger operated electrical switch, in which appreciable movement of the plunger is necessary to separate electrical contacts in the switch.

A. further object of the invention is to provide an electrical switch having cooperating contact members which are forced together by dual spring means, in which the dual spring means are arranged to permit movement of one Contact member a predetermined distance before electrical Contact between the members is broken.

A still further object of the invention is to provide an electrical switch having a contact member mounted by spring means on a base disposed for movement toward and away from another contact member, in which the spring means allows the contact members to maintain electrical contact during movement of the base a predetermined distance away from the other `contact member.

A still further object of the invention is to provide an electrical switch having contact members disposed to be forced together by an operating spring and an auxiliary spring, whereby extension of the operating spring to force the members into contact causes compression of the auxiliary spring.

Other objects of the invention will, in part, be obvious, and will, in part, appear hereinafter.

For fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description, taken in conjunction with the accompanying drawing, in`

which:

Fig. 1 is an exploded view of the component parts of the device;

Fig. 2 is a view in elevation, partly in section, of the assembled device, in which the switch is in the on position;

Fig. 3 is a View similar to Fig. 2 in which the switch operating plunger has been moved inwardly a predetermined distance, but not sufficiently far to break the electrical contact;

Fig. 4 is a view similar to Fig. 2 in which the Switch is in the oif position;

Fig. 5 is a view in section taken on line 5-5 of Fig. 2;

Fig. 6 is a view in section taken online 6-6 of Fig. 2. y

Referring to the drawing there is illustrated a push button switch assembly I0, which is adapted to snap into engagement with a door molding I2, and is disposed for operation by an associated closurefmember I4. The switch I0 comprises a pair of contact members I6y mounted on a base I8 which is movable within a housing 20,r and a shorting ring 22 mounted opposite the contact.

members on a xed base 24. The xed base 2.4 is provided with an opening 26 for a purpose which will appear hereinafter. The movable base I8 is slidable in the housing 20 toward and away from the fixed base 24 to make and break an electrical circuit between the members I6 and the shorting ring 22.

The Contact members I6 are so mounted on the movable base I8 as to allow movement of the members a predetermined distance toward and away from the base, and are biased outwardly from the base by Contact springs 28 mounted behind the Contact members in recesses 30. To provide for electrical connections to the contact members, openings 32 are provided in the base I8, through which lead wires 34 may be disposed.

An operating plunger 36 is mounted on the base I3 to extend through the opening 26 in the fixed base, and protrudes from the housing 28 when the switch is in the on position. An insulating stop ring 38 is provided on the plunger 36 to engage the contact members I6 and limit the distance they may be extended by the contact springs 28.

A switch operating spring 4@ is disposed in the housing behind the movable base I 8, to bias the base and the contacts toward the shorting ring 22, and to extend the plunger from the housing. The operating spring 40 should be appreciably stronger than the combined strength of the contact springs, for a purpose which will appear hereinafter.

'Ihe operation of the switch is best illustrated by Figs. 2 4. As shown in Fig. 2, the switch is in the on position when the plunger is extended by the biasing force of the operating spring 40 bearing against the movable base I8, thereby forcing the contacts I6 against the shorting ring 22, to complete an electrical circuit between the contacts. The biasing force of the spring 40 also compresses the contact springs 28 by forcing the contacts I inwardly toward the base I8.

As illustrated in Fig. 3, when the closure member I4 bears against the plunger 36, the plunger and base I 8 are forced inwardly, compressing the operating spring 40. Movement of the base I8 away from the base 24 allows the contact springs 28 to expand, forcing the contact members I6 away from the base I8 to maintain them in contact with the shorting ring 22. As illustrated in Fig. 4, when the closure member I4 forces the plunger 3B and base I 8 further inwardly, the contact members I6 engage the stop ring 38, and further movement of the plunger and base inwardly moves the Contact members away from the shorting ring 22 to break the electric circuit therebetween.

It will be readily apparent that numerous modications may be made in the device. For instance, in some cases it may be desirable to have only one contact member mounted on the movable base, in which case the shorting ring may be replaced by a single Contact member which may be grounded to complete an electrical circuit. If it is more convenient to mount the contact members solidly on the movable base, auxiliary springs may be mounted between the shorting ring and the fixed base, or between the fixed base and the housing to achieve the desired resiliency between the Contact members.

Since certain other obvious changes may be made in the device without departing from the scope of the invention, it is intended that all matter contained herein be interpreted in an illustrative and not in a limiting sense,

I claim:

1. An 4electrical switch comprising a substantially tubular casing having inturned flanges at one end dening an opening, an insulating end member secured in the other end of said casing having an aperture extending therethrough into the casing, and a shorting contact member surrounding the aperture on the face disposed within the casing, a contact-carrying member of insulating material disposed within said casing provided with an operating plunger extending through the aperture of said insulating end member, said contact-carrying member having contact-receiving cavities on a face opposite said end member, and contact-retaining means on said plunger overlying said cavities, contact members loosely disposed in said cavities, connecting wires extending from said contacts through said contact-carrying member and the opening defined by said inturned flange, spring means disposed in said contact cavities for urging said contacts toward said contact-carrying means, and other spring means disposed in said casing between said ange and said contact-carrying member for urging said contact-carrying member toward said other end, said plunger through said aperture, and, said contacts into contact with said snorting Contact member.

2. An electrical switch in accordance with claim 1 wherein the contact-retaining means on the plunger comprises an insulating ring secured to said plunger in spaced relation to said contact-carrying member.

CLEMENT A. WOODWARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 731,375 Liggett June 16, 1903 1,071,169 Mertz Aug. 26, 1913 2,436,898 Rickmeyer Mar. 2, 1948 Certificate of Correction Patent No. 2,530,364 November 14, 1950 CLEMENT A. WOODWARD It is hereby certified that error appears in the printed speccaton of the above numbered patent requiring eorrectlon as follows:

Column 4, line 22, for the hyphenated Word contact-carrying read contact-@Mining and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Office. Signed and sealed this 9th day of January, A.. D. 1951.

[SEAL] THOMAS F. MURPHY,

Assistant @ammissioner of Patents.

Certificate of Correction Patent No. 2,530,364.- November 14, 1950 CLEMENT A. WOODWARD It is hereby certed that error appears in the printed speceaton of the above numbered patent requiring correction as follows:

Column 4, line 22, for the hyphenated Word contact-carrying read contact-retaining and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Oce. Signed and sealed this 9th day of January, A. D. 1951.

[SEAL] THOMAS F. MURPHY,

Assistant ommz'ssz'oner of Patents.

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