Abstract: By providing an inexpensive, easily manufactured coil spring member as a cam surface which is spring biased and is controllably, reciprocatingly axially cycled by a rotating cam follower, an inexpensive, continuous operable, fail-safe, dependable, portable, impactor handpiece is achieved. In the preferred embodiment, the portable, hand-held impacting tool of the present invention also incorporates an inexpensively manufactured and easily installed key member retainingly engaged in an axially elongated slot to prevent unwanted rotation of the anvil member, while assuring continuous, trouble-free reciprocating axial movement thereof.

Abstract: A foot pedal operated motor control is provided for controlling the speed of a motor. The entire motor control circuit is mounted in a foot pedal housing which circuit includes a generally disc shaped potentiometer having a rotatable and a stationary member with the movement of the rotatable member with respect to the stationary member determining the resistance of the potentiometer which controls the current to a motor whose speed is to be controlled. The disc shaped potentiometer has an opening therethrough. A foot pedal is pivotally mounted on the housing overlying the potentiometer and a helical member extends between the foot pedal on one end thereof and into the opening of the disc shaped potentiometer on the other end thereof.