Electric switch with magnetic-assist means to assist switch in closing and remaining closed against high currents

Claim 2

An electric switch comprising: a. a first contact and a second contact that is movable into and out of engagement with said first contact, b. triggering means operable to cause current to flow between said contacts while said contacts are substantially fullyseparated, c. magnetic-assist means for developing for transmission to said second contact a magnetic force acting in a switch-closing direction which varies directly in accordance with the current through said contacts, d. means for transmitting said magnetic force from said magnetic-assist means to said second contact comprising means for limiting to a relatively low value the portion of the magnetic force transmitted when said contacts are in and near their fully-separated position but transmitting to said second contact a relatively large portion of said magnetic force when said contacts are in and near their fully-closed position, e. spring means biasing said second contact toward closed position when said contacts are fully separated, and f. releasable restraining means for holding said second contact in said fully-separated position against the bias of said spring means and releasable to permit said spring means to drive said second contact toward engaged position.

Claim 3

The switch of claim 1 in which: a. said spring means comprises a closing spring that discharges during the early stages of a switch-closing operation to accelerate said second contact in a switch-closing direction, and b. snubbing means is provided for blocking said spring from further discharging at a point substantially ahead of the point at which said contacts engage during a switch-closing operation.

Claim 4

The switch of claim 1 in which: a. said means for limiting the force transmitted from said magnetic assist means comprises a toggle linkage connected between said magnetic-assist means and said second contact which operates near an on-center position when said second contact is near its fully-separated position, b. said toggle linkage having a portion serving as an output end during a closing operation through which forces from said magnetic-assist means are transmitted to said movable contact, c. the toggle linkage being so constructed that the portion of the input force transmitted therethrough to said output end is relatively low when said toggle linkage is operating near its on-center position compared to that portion transmitted when the toggle linkage is operating further away from its on-center position.

Claim 5

The switch of claim 1 in which: a. said means for limiting the force transmitted from said magnetic-assist means to said second contact comprises first and second toggle linkages, both of which are connEcted between said magnetic-assist means and said second contact, b. said first toggle linkage being effective to transmit force from said magnetic-assist means to said second contact when said contacts are near their fully-separated position, c. said second toggle linkage being ineffective to transmit force from said magnetic-assist means to said second contact when said contacts are near their fully-separated position, d. means operable after the first stages of a switch-closing operation for rendering said first toggle linkage ineffective and said second toggle linkage effective to transmit force from said magnetic-assist means to said second contact, e. said second toggle linkage operating near its on-center position when it first becomes effective and operating further away from said on-center position as the switch-closing operation progresses, f. said second toggle linkage having a portion serving as an output end during a switch-closing operation through which forces from said magnetic-assist means are transmitted to said movable contact, g. said second toggle linkage being so constructed that the portion of the input force transmitted therethrough to said output end is relatively low when said second toggle linkage is operating near its on-center position compared to that portion transmitted when said second toggle linkage is operating further away from its on-center position.

Claim 6

The switch of claim 4 in which said first toggle linkage is substantially on-center when said contacts are fully separated and remains near center during the closing operation until said second toggle linkage becomes effective, said first toggle linkage having a portion serving as an output end during a closing operation through which forces from said magnetic-assist means are transmitted to said movable contact when said first toggle linkage is effective, and said first toggle linkage being so constructed that the portion of the input force transmitted therethrough to said output end of the first toggle linkage is relatively low when said first toggle linkage is operating near its on-center position compared to that which would be transmitted to said toggle linkage if the toggle linkage were operating further away from its on-center position.

Claim 7

The switch of claim 3 in which: a. said spring means comprises a closing spring that discharges during the early stages of a switch-closing operation to accelerate said second contact in a switch-closing direction, and b. snubbing means is provided for blocking said spring from further discharging at a point substantially ahead of the point at which said contacts engage during a switch-closing operation.

Claim 8

The switch of claim 4 in which: a. said spring means comprises a closing spring that discharges during the early stages of a switch-closing operation to accelerate said second contact in a switch-closing direction, and b. snubbing means is provided for blocking said spring from further discharging at a point substantially ahead of the point at which said contacts engage during a switch-closing operation.

Claim 9

The switch of claim 5 in which: a. said spring means comprises a closing spring that discharges during the early stages of a switch-closing operation to accelerate said second contact in a switch-closing direction, and b. snubbing means is provided for blocking said spring from further discharging at a point substantially ahead of the point at which said contacts engage during a switch-closing operation.

Claim 10

The switch of claim 1 in which: a. said magnetic-assist means comprises two side-by-side bars electrically connected in series with said contacts in such a manner that current at any instant flows in opposite directions through said bars to develop a repulsive magnetic force therebetween that drives one of said bars in a switch-closing direction, b. and said means for transmitting said magnetic force is connected between said one bar and said second contacT.

Claim 11

In the switch of claim 1, a. a second set of contacts comprising a first contact and a second contact that is movable into and out of engagement with said first contact, b. additional triggering means operable substantially simultaneously with triggering means of claim 1 to cause current to flow between the contacts of said second set while the contacts of said second set are substantially fully separated, c. means for connecting both sets of contacts in series so that current flows in series therethrough when both said triggering means are operated, d. the electromagnetic assist means of claim 1 being common to the two sets of contacts and being connected in series with said two sets of contacts to develop responsive to current flow therethrough a second magnetic force acting in a switch-closing direction on the movable contact of said second set of contacts, e. means corresponding to the force transmitting means of (d) of claim 1 for transmitting said second magnetic force to the second contact of said second set, f. second spring means biasing the second contact of said second set toward closed position when the contacts of said second set are fully separated, and g. the releasable means of (f) of claim 1 also holding the second contact of said second set in its fully-separated position and, upon release, permitting said second spring means to drive said second contact of said second set toward engaged position.

Claim 12

The switch of claim 10 in which said magnetic-assist means comprises two side-by-side bars through which current at any instant flows in opposite directions to develop a repulsive effect therebetween that produces said two magnetic forces, one of said force-transmitting means being connected between one of said bars and one of said second contacts, and the other of said force-transmitting means being connected between the other of said bars and the other of said second contacts.