Abstract: The front idler roller of the belt sander is mounted by a yoke for swinging movement in a plane containing the axes of both the drive and idler rollers and for shifting movement along a path generally toward and away from the drive roller. A transversely disposed shaft mounted by the tool housing has a cam formation at one end thereof received within an opening formed in the yoke; the cam is captured in this opening formed in part by a cam follower. The shaft is mounted for axial and rotational movements. Rotation of a first knob on the other end of the shaft causes the latter to move axially thereby to swing the idler roller for centering of the belt. Rotation of a second knob, concentric with the first knob and also mounted on other other end of the shaft, causes the shaft to rotate thereby activating the cam for shifting the idler roller toward the rear roller for easy belt replacement.

Abstract: 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.

Abstract: A power tool includes manually operated selector means for alternately establishing rotary-hammer and hammer-only modes of operation for the associated drill bit. The attachment is in the form of an elongated member having a longitudinally extending blind bore for receiving the drill bit; retaining means are provided for releasably mounting the attachment on the drill bit. An annular shoulder defining the mouth of the blind bore is in abutting engagement with another annular shoulder, the latter being arranged to receive impact blows from the hammer mechanism of the power tool. In one embodiment, this second mentioned annular shoulder is constituted by a tappet forming part of the hammer mechanism. In another embodiment, this second mentioned annular shoulder is an integral part of the drill bit. Impact blows are transmitted to the attachment only through the area of engagement of the aforesaid annular shoulders.

Abstract: The striker is mounted in a barrel for axial reciprocal movement thereby to impart successive hammer blows to the end of a tool shank element extending into one end of said barrel. An actuator is connected to the piston by lost-motion means. A motor driven, mechanical crank assembly is connected to the actuator for reciprocating the piston such that its velocity in the hammer-direction is greater than its velocity in the return-direction.