US1679334A - Electric switch - Google Patents

Description

July 31, 1928; v 1,679,334

H. A. DOUGLAS mcnuc SWITCH Filed aamz m 192 Patented July 31, 1928.

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nanny A. nofiGLAs, or imoNsoN, ivrrcrrman .ELECTRIC SWITCH;

Application filed January '27, 1926. I Serial No. :84,098;u'

Myi invention relates ,to electrie switches.

formed of insulation, and which arei'ela 6 tivelyrotatable or otherwise relatively movable to bring the contacts thereon into and out of contacting relation.

In other switches as at present constructed, the insulating contact carrying member 1s 10 engaged by the contact upon the other member in the adjustment of the switch to circuit opening and circuit closing positions. Due to the friction between this contact and the insulating member, particles of insulation are worn from this member and are carried by the contact engaging it causing imperfeet and resistance producing engagement between the contacts when brought into contacting alignment.

The device of my invention serves to move one contact carrying member from the other when the switch is being adjusted so that the insulatin contact carrier will not then be engaged by the contact upon the other contact carrier. One of the contact carriers has a portion engaging the other which causes this result when the contacts are out of contacting alignment, and permits the moved carrier to approach the other when the contacts are in contacting alignment to permit engagement between the contacts.

The invention will be more fully explained in connection with the accompanying drawing in which Fig. 1 is a sectional view on line 1-1 of Fig. 2, on a smaller scale; Fig. 2 is a sectional view on line 22 of Fig. 1; Fig. 3 is a rear face View of a portion of one of the contact carriers, showing a contact thereon; and Fig. 4 is a sectional view on line 44 of Fig. 3.

The structure illustrated employs a casing having a front end wall 1 and a side wall 2, the Wall 1 being essentially flat and the wall 2 being cylindrical. The rear end of the switch casing is closed by a contact carrier 3 which is separably assembled with the easing by means of bayonet pins 4 upon the contact carrier receivable in bayonet slots 5 provided in the casing wall 2. The contact carrier carries contacts 6 engageable by con tacts 7 that are carried upon a metallic ring 8,and which are coupled by means of the spring-pressed lungers 9 with a contact actuator 10 in tiie form of a ring of insulation. This contact actuator is assembled with the wings 11 extending inwardly from the hub portion--12iof a handlen13. The handle hub ,is provided with: a flanges-14; received between the endwall l -of the casin and the finishing cover;plate,15, whereby the handle isconfined toan axis of rotation which is coincident with the casing axis.

The coiled springs 16 that press the plungers 9 against the bottoms of the cupshaped cavities 17 in the insulating ring 10 are housed in spring barrels 18 which are carried by and project forwardly from the metallic ring or contact carrying member 8. These springs not only press the plungers 9 forwardly but also press the metallic contact carrying member 8 toward theinsulating contact carrying member 3, decreasing the space betwen the contact carriers when the contacts engage. The contacts 6 and the contacts 7 are arranged upon a circle that is concentric with the axis of the handle so that as the handle is turned, the contacts7 are brought into and out of contacting alignment with their complemental contacts 6 whereby the circuits including the engageable contacts are either closed or opened. The contacts 7 are provided with portions 19 rearwardly projecting therefrom and which ride or rest upon the insulating member 3 to separate the carriers 3 and 8 further when the contacts? are out of contacting alignment with their complemental contacts 6, to separate contacts 7 from carrier 3 against the force of springs 16 for the purpose stated. The contacts 6 are formed with cup-shaped recesses 20 at their front ends which freely receive the projecting portions 19 when the contacts 7 arerin contacting alignment with the contacts 6, to reduce the space between the carriers and'permit the springs 16 to force engagement of the contacts. In order to avoid undue wear, the projecting portions 19 are desirably in the form of rotatable balls which are received and turned within seats formed in the contacts 7 and which are held in place by means of seats 21 that are in the form of dished plates havlng ears 22 passing through the member 8 whereby the seats 21 are rigidly secured to the member 8. The balls 19 will gather but little, if any, of particles of insulation from the insulating member 3 and whatever insulating particles may be gathered by the balls do not find lodgement upon the portions of the contacts 7 that are engageable with the contacts 6. Each ball is free of the tacts into and out of contacting alignment, one of said contacts having a recess in its contacting face and the other contact having a ball projecting therefrom and rotatable upon the carrier for the first Contact, said ball being receivable within said recess, the contact having the ball also having another portion engageable with the other contact and holding the ball out of engagement with said other contact when the contacts are in engagement.

In witness whereof, I hereunto subscribe my name.

HARRY A. DOUGLAS.

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