US1075238A - Electrical switch. - Google Patents

Description

sure decreasing as the distance' from the bend increases.

The bars 1 and 3 being secured yith their faces in actual contact, the knife bar 7 enteringl between the two halves of the switch, in bringing the bars 1 and 2 together into the position shown in Fig. 3, produces a result which may be Idescribed as rocking the bar 8 upon the bar 1, that is, the point of divergence from contact is transferred toward the base 4 as the knife bar 7v enters between the rjaws of the switch.

The two bars 1 and 3 may be considered as levers having a measure of flexibility. Their fulcrum point is the point of divergence from contact. As the knife bar 7 enters between the two bars 3, the bars 1 and 3 are bent and the point of contact travels backward toward the base. ln consequence the pressureof the springr against the knife bar is not being greatly reduced as it passes inward between the jaws. From this it results that there is a better electrical contact between the knife bar and the jaws. The same rocking action, or transference of the fulcrum point between the supporting bar 2 and the spring bar 1 takes place as has been described as occurring between the bars l and 2. This results in a much more equal pressure upon the knife bar at'all points than if these members were all actinginde- Apendently, without any effect upon each other. y y

lf the knife bar 7 should happen to not be parallel with the true planes of the jaws, the j aws` are sumciently flexible to adjust themselves to this and make a true and large contact in spite of the twist of the knife bar.

Securing the two bars 1 and 3 -with their faces in close and unyielding contact at their outer ends, is superior to an open bend, for many reasons. As above pointed out it results in a transference of the fulcrum point along the bars so as to keep this fulcrum point near the entering blade at all times, thus making the pressure exerted by the bars upon the blade more nearly equal at all points. This produces a superior contact than would follow were the two bars connected by an open bend, as in the latter case the pressure upon the blade would .rapidly decrease as it passed inward between the jaws. Arcing, which always occurs to a greater or less extent upon opening and closing a switch, always acts upon that portion where the make and break occurs. This switch. thus reducing the cross section of the arm, Second, b annealing the material of the switch and estroying its resilient qualities. A s, in my construction, the point of arcing is confined to that portion in which the two parts of the jaw are secured with their faces in Contact, the material throughout the entire area affected by arcing, acts only as a physical or binding connection between the jaws and not at alll as a spring'. For this function its area is so great that a large reduction in area would still leave it with ample strength. As to the effect of the annealing action, this will have no effect upon the spring action of the jaws, as the area affected in this way at no time acts as a spring, this action being confined to the body of the jaws sufficiently removed from the arcing zone to be unaffected by thearcing.

` What 1 claim as my invention is: 1. A jaw member for electrical switches comprising two spring-like members secured together at one end with their faces in contact, one of said members being secured at. its opposite end to av support and the other constituting the contact member, said members being differently curved to normally hold their maj or part separated, and adapted to have said normallyseparated parts brought gradually into contact as the switch passes over the Contact member.

2. 1n an electric switch, in combination, a base, a pair of spring arms secured at one end to said base and projecting therefrom in the same'ldirection but in separated relation, a spring arm secured to and with a side surface in cont-act with the inner surface of the outer .end of each of said yfirst-mentioned arms, the arms so connected being given an initial curvature acting to separate them as they extend away from their point of union when unrestrained but permitting bringing said surfaces into contact by the pressure of the movable member of the switch inclosing.4

3. A jaw member for electric switches comprising two spring-like arms secured toj gether at one end with side faces in close contact, the secured ends of said arms being' curved to normally slightly diverge their free portions away from their secured ends,

the free end of one of said armsbeing longer than the other, and means for securing said extended end to a support. y

4. In an electric switch, the combination with a base, of spring arms secured to the base and projecting in the same direction from the base but in separated relation,

rst mentioned spring arms and extendingy fixed my signature at Seattle, Washington, backvxrd therebeween, the imctedspring this 6th day of July, 1911. arms eing curve to norma 'verge away from theirV point of connection, said inner O' N' WISWELL 5 set of arms serving as the contact members Witnesses: of thecomplemental part oie-the switch. H. L. REYNOLDS,- In testimony .whereo I have herento af- R. C. PoLLn'rr.

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