Vacuum-type circuit breaker with force-supplementing means for increasing current-carrying abilities

Claim 2

A vacuum-type circuit breaker comprising: a. a vacuum interrupter comprising: a1. a first contact and a second contact movable into and out of engagement with said first contact, a2. an evacuated envelope in which said contacts are located, a3. a contact rod supporting said second contact and extending through a wall of said envelope, b. an operating mechanism through which contact-closing force is applied to said contact rod during a closing operation and through which contact-opening force is applied to said contact rod during an opening operation, c. a wipe mechanism interposed between said contact rod and said operating mechanism and comprising a wipe spring through which said contact-closing force is transmitted from said operating mechanism to said contact rod during closing, said wipe spring yielding to permit overtravel of said operating mechanism after said contacts have engaged at the end of a closing operation, d. latching means comprising a cam mechanism operable when said second contact is in and near its closed position for exerting a supplemental closing force on said contact rod that is transmitted to said contact rod via a force-transmitting path that effectively bypasses said wipe spring, e. and means controlled by said operating mechanism for disabling said Latching means early in an opening operation before an opening force is applied to said contact rod through said operating mechanism, said wipe mechanism containing lost motion for providing a delay in the application of said opening force to said contact rod following initiation of an opening operation.

Claim 3

The circuit breaker of claim 1 in which: a. said latching means and cam mechanism comprises a movable latch member and spring means for moving said latch member into a terminal position as said second contact moves into its fully engaged position, b. said latch member has a cam surface, and said contact rod is coupled to a follower that is engaged by said cam surface when said second contact is in and near its fully engaged position, c. said cam surface is shaped to exert a wedging action on said follower as said latch member moves toward its terminal position, said wedging action developing a force on said follower acting in a contact-closing direction.

Claim 4

The circuit breaker of claim 1 in which said cam mechanism provides a wedging action that develops said supplemental closing force on said contact rod.

Claim 5

A vacuum-type circuit breaker comprising: a. two vacuum interrupters each comprising: a1. a first contact and a second contact movable into and out of engagement with said first contact, a2. an evacuated envelope in which said contacts are located, a3. a contact rod supporting said second contact and extending through a wall of said envelope, b. the contact rods of said interrupter projecting from their respective envelopes toward each other, c. a common operating mechanism through which contact-closing force is applied to both of said contact rods during a closing operation and through which contact-opening force is applied to both of said contact rods during an opening operation, d. Two wipe mechanism respectively interposed between said contact rods and said common operating mechanism and each comprising a wipe spring through which contact-closing force is transmitted from said operating mechanism to the contact rod of the associated interrupter during closing, each of said wipe springs yielding to permit overtravel of said operating mechanism after the contacts of the associated interrupter have engaged at the end of a closing operation, e. latching means operable when both of said second contacts are near their closed positions for exerting supplemental closing force on both of said contact rods that is transmitted to said contact rods via force-transmitting paths that effectively bypass each of said wipe springs, f. said latching means comprising a latch member common to the two interrupters through which a portion of the magnetic force tending to open one set of contacts is imparted to the other set of contacts as a force in a direction to hold said other set closed.

Claim 6

A vacuum-type circuit breaker comprising: a. two vacuum interrupters each comprising: a1. a first contact and a second contact movable into and out of engagement with said first contact, a2. an evacuated envelope in which said contacts are located, a3. a contact rod supporting said second contact and extending through a wall of said envelope, b. the contact rods of said interrupter projecting from their respective envelopes toward each other, c. a common operating mechanism through which contact-closing force is applied to both of said contact rods during a closing operation and through which contact-opening force is applied to both of said contact rods during an opening operation, d. Two wipe mechanism respectively interposed between said contact rods and said common operating mechanism and each comprising a wipe spring through which contact-closing force is transmitted from said operating mechanism to the contact rod of the associated interrupter during closing, each of said wipe springs yielding to permit overtravel of said operating mechanism after the contacts of the associated interrupter have engaged at the end of a closing operation, e. latching means operable when both of said second contacts are near their closed positions for exerting supplemental closing force on both of said contact rods that is transmitted to said contact rods via force-transmitting paths that effectively bypass each of said wipe springs, f. said latching means comprising a latch member common to the two interrupters through which a portion of the magnetic force tending to open one set of contacts is imparted to the other set of contacts as a force in a direction to hold said other set closed.

Claim 7

The vacuum circuit breaker of claim 4 in which the mounting of said common latch member allows the latch member to shift radially with respect to its pivot axis.

Claim 8

A vacuum-type circuit breaker as defined in claim 4 in which: a. said common latch member is pivotally mounted and has cam surfaces at its opposite ends through which said supplemental closing force is transmitted to said contact rods, b. said common latch member is so mounted that it can shift bodily in a direction radially of its original pivot axis to maintain both of said cam surfaces in engagement with their respective followers when the contacts of both interrupters are engaged despite unequal contact erosion, and c. said latching means further comprises spring means biasing said latch member into a position where both of said cam surfaces engage said followers when the contacts for both interrupters are engaged.

Claim 9

The vacuum-type circuit breaker of claim 6 in which said common latch member has a slot therein receiving a stationary pivot pin for said latch member, the slot allowing said latch member to shift witH respect to said pivot pin in a direction along the length of said slot but blocking shifting transversely of said slot.

Claim 10

A vacuum-type circuit breaker as defined in claim 4 and further comprising: means controlled by said operating mechanism for disabling said latching means early in an opening operation before an opening force is applied to said contact rod through said operating mechanism, said wipe mechanism containing lost motion for providing a delay in the application of said opening force to said contact rod following initiation of an opening operation.

Claim 11

A vacuum-type circuit breaker as defined in claim 8 in which: a. said means for disabling said latching means comprises releasing means responsive to an opening operation of said operating mechanism, b. means is provided for disabling said releasing means at a predetermined point in said opening operation after said latching means has been disabled, c. and means is provided for maintaining said releasing means disabled during a sufficient portion of said closing operation to allow said latching member to exert a closing force on said contact rod from an instant just preceding contact engagement during a subsequent closing.

Claim 12

A vacuum-type circuit breaker as defined in claim 1 in which: a. said means for disabling said latching means comprises releasing means responsive to an opening operation of said operating mechanism, b. means is provided for disabling said releasing means at a predetermined point in said opening operation after said latching means has been disabled, c. and means is provided for maintaining said releasing means disabled during a sufficient portion of said closing operation to allow said latching member to exert a closing force on said contact rod from an instant just preceding contact engagement during a subsequent closing.

Claim 13

The vacuum type circuit breaker of claim 10 in which: a. said releasing means is maintained in a condition to transmit thrust to said latching means when said contacts are engaged, b. the disabling means for said releasing means renders said releasing means ineffective to transmit thrust to said latching means at said predetermined point in said opening operation.