The Singer Company

John Houser, Jr

Thomas C Laughon

A latching arrangement is provided in a high speed battery charging circuit. The latching arrangement includes a momentary switch for momentarily changing a voltage level on a gate controlling capacitor for a gate controlled high current path and an inversion circuit between the capacitor and the gate, thus permitting a voltage provided by a thermostatically controlled switch to be applied to the capacitor for controlling the gate. The thermostatically controlled switch senses battery cell temperature and permits fast charging for temperatures below a threshold. The momentary switch is momentarily activated to initiate the fast charging operation. Upon sensing a temperature rise, the thermostatically controlled switch terminates fast charging and initiates trickle charging. When the battery cell cools and the thermostatically controlled switch again closes, the latching arrangement prevents resumption of a fast charge operation.

Battery charger circuit

A power tool in which feed rate information is used as a means of changing cutting implement speed to maintain an optimum chip rate removal. As the tool is loaded by a feed rate increase, the motor speed will increase to that point empirically determine to provide a good finish for the material and cutting implement size selected. If the load decreases, the motor speed will correspondingly decrease to that speed which will provide a good finish for the material and cutting implement size selected with out overheating of the material. A limit would be set to indicate to an operator when he is at the upper limit of the speed and feed rate range and turn off the tool after a short period of time to prevent destructive overheating.

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Pickens, SC, United States of America

John Houser, Jr