Skil Corporation

Louis J Vassos

James R Hartmann

David C Kilinskis

James S Stanley

John M Lord

John W Heinz

A cordless powered ratchet wrench includes a ratchet actuator that selects a direction of rotation of an output shaft that is adapted to hold rotating tools for use. The ratchet actuator also serves as a ratcheting stop to permit a limited amount of ratcheting motion for manual tightening or loosening of a nut, bolt or the like. A lost-motion drive transmits power from a battery to the output shaft while permitting nearly two full circles of ratcheting rotation. An external pushbutton operates internal switches to connect a rechargeable battery in a desired direction, and also functions as an interlock to prevent reversal of the direction in which torque is applied while the pushbutton is engaged. The ratchet actuator that selects a desired direction of rotation also functions to provide a positive driving surface for manual exertion of torque by an operator and as a ratchet to permit rotation in the opposite direction when the wrench is ratcheting, and it operates a switch to select a direction of powered motion. Exposed terminals prepare the wrench to be inserted into a charger for recharging the battery.

Cordless powered ratchet wrench

A battery charging circuit is operable for recharging batteries in both trickle and fast charge modes. The fast charge mode is initiated and maintained by enabling a silicon controlled rectifier in circuit between a current source and the battery. A capacitor maintains the SCR in the operative state until the battery reaches full charge. A thermostatically controlled switch terminates the fast charge mode. The battery is then trickle charged for an indefinite period. Reversion to the fast charge mode is prevented by discharging the capacitor associated with the SCR when the thermostatically controlled switch opens.

Battery charging circuit for portable power tool

A double pole, trigger actuated switch employs a bridge contact and a separate contactor for opening and closing both lines from a source of current to an associated power tool. The bridge contact is always closed first and opened last with respect to the contactor so that the former is not subjected to arcing and may be made smaller and less expensively than the latter. The contactor is of the fast closing type constructed to minimize arcing. A speed control circuit is associated with the contactor. The entire switch, including the speed control circuit, is provided in a compact housing for mounting in small portable hand tools such as electric drills. A heat sink is exposed to the ambient air by virtue of louvers in the switch housing.

Power tool switch including speed control

A cordless electric drill has a housing formed by two clam-shell sections secured together by a plurality of fasteners. These housing sections define a closed motor and gear compartment which receives a sub-assembly, the latter including a generally U-shaped gear box frame mounting a small D.C. electric motor, a plurality of reduction gears and a spindle. A drill chuck is mounted on the spindle. The sub-assembly and the housing sections include co-operating mounting formations, defined in part by projections and cavities, which mounting formations serve to mount the sub-assembly in place in response to securing the clam-shell housing sections together by the aforesaid fasteners.

Growing community of inventors

Park Ridge, IL, United States of America

Louis J Vassos