Charger for rechargeable cell

Claim 2

Charging apparatus for recharging a cell of known capacity with a predetermined amount of charge without overcharging the cell by first discharging the cell to a low level of approximately zero comprising: a. a heater circuit for a resistance heater, a cell discharge circuit for reducing the level of charge in the cell to approximately zero and actuating means for simultaneously actuating both circuits; b. thermally responsive relay means adjacent said resistance heater and having contact means thereon; c. a charging circuit including a source of charging current in series with said rechargeable cell and contact means on said thermally responsive relay to provide a preselected constant charge rate, said charging circuit being actuated by said relay means in response to heat from said heater; d. means for deactuating said cell discharge circuit when said charging circuit is actuated; and e. means for reducing the heat generated by said heater after said charging circuit is actuated to provide a timed charge to said cell; whereby said charge rate may be preselected to provide within the timed interval a predetermined amount of charge which is less than the total capacity of said cell to prevent overcharging.

Claim 3

The charger of claim 1 wherein said means for actuating the cell discharge circuit and heater circuit comprise manually actuated means.

Claim 4

The charger of claim 1 wherein said contact means on said thermally responsive relay means include normally open contacts which are closed by said relay means in response to heat received from said heater.

Claim 5

A charger for a rechargeable cell having a sequential discharge mode and a charging mode comprising: a. a cell discharge circuit, a first heater circuit for a resistance heater and means for simultaneously actuating both circuits; b. thermally responsive relay means adjacent said resistance heater including first normally open contact means in series with said heater circuit and manually actuable to a closed position and second normally open contact means closable in response to heat from said heater, the closing of said second contact means simultaneously opening said first contact means; c. a charging circuit including a source of charging current in series with said rechargeable cell and contact means on said thermally responsive relay, said charging circuit being actuated by said relay means in response to heat from said heater; d. means for deactuating said cell discharge circuit when said charging circuit is actuated; e. and means for reducing the heat generated by said heater after said charging circuit is actuated to provide a timed charge of said cell comprising a second heater circuit in series with said second contact means and including impedance means therein to reduce the flow of current to said heater.

Claim 6

A charger for a rechargeable cell having a sequential discharge mode and a charging mode comprising: a. a cell discharge circuit, a first heater circuit for a resistance heater and means for simultaneously actuating both circuits; b. thermally responsive relay means adjacent said resistance heater including first normally open contact means in series with said heater circuit and manually actuable to a closed position and second normally open contact means closable in response to heat from said heater, the closing of said second contact means simultaneously opening said first contact means; c. a charging circuit including a source of charging current in series with said rechargeable cell and contact means on said thermally responsive relay, said charging circuit being actuated by said relay means in response to heat from said heater; d. means for deactuating said cell discharge circuit when said charging circuit is actuated; e. and means for reducing the heat generated by said heater after said charging circuit is actuated to provide a timed charge of said cell comprising a second heater circuit in series with said second contact means and including impedance means therein to reduce the flow of current to said heater.

Claim 7

The charger of claim 4 wherein said contact means includes at least one magnetized contact.

Claim 8

A charger for a rechargeable cell having a sequential discharge mode and charging mode comprising: a. a manually depressable push-button having first contact means associated therewith for simultaneously closing a cell discharge circuit and a heater circuit for a heater; b. latching means for said contact means to maintain said contact means in said circuit closing position for a predetermined period of time; c. a charging circuit including a source of charging current in series with said cell; and d. thermally responsive contact means adjacent said heater movable in response to heat to (1) unlatch said first contact means and break the discharge and heating circuits closed thereby and (2) to close contacts energizing said charging circuit for a predetermined time period until said thermally responsive contact means cools sufficiently to open said charging circuit contacts.

Claim 9

A charger for a rechargeable cell having a sequential discharge mode and charging mode comprising: a. a manually depressable push-button having first contact means associated therewith for simultaneously closing a cell discharge circuit and a heater circuit for a heater; b. latching means for said contact means to maintain said contact means in said circuit closing position for a predetermined period of time; c. a charging circuit including a source of charging current in series with said cell; and d. thermally responsive contact means adjacent said heater movable in response to heat to (1) unlatch said first contact means and break the discharge and heating circuits closed thereby and (2) to close contacts energizing said charging circuit for a predetermined time period until said thermally responsive contact means cools sufficiently to open said charging circuit contacts.

Claim 10

The charger of claim 6 wherein said first contact means includes first and second yieldable contact arms, said first contact arm is urged by depression said manually depressible push-button against said second yieldable arm and simultaneously is latched into contact with said thermally responsive contact means.