Abstract: A sander (1) has a motor (3) with a motor shaft (4) mounted in a bearing box (11) via an eccentric ball bearing (10). Coupled to the bearing box (11) is a pad (12) having a bulged square shape in a horizontal cross section. The sander (1) further includes a skirt (6) with an opening (6a) on which a synthetic (polyurethane rubber) brake ring (17) is mounted. The brake ring (17) comprises an outer peripheral portion (18) and a plurality of contact portions (19) disposed at regular intervals around the outer peripheral portion (18). Each contact portion (19) is bulged toward the center of the brake ring (17) with both ends connected to the outer peripheral portion (18). Also, the contact portions (19) are elastic so as to deform in the radial direction. The contact portions (19) together form a through-hole (21) which is slightly smaller than the bearing box (11) for receiving the bearing box.

Abstract: A hammer drill includes a spindle supported by a housing and movable in an axial direction relative to the housing within a predetermined range, a motor for rotating the spindle, a rotary cam member fixedly mounted on the spindle, a clutch cam member which supports a weight member is axially movably mounted on the spindle, and a biasing member for normally biasing the clutch cam member and weight member toward the rotary cam member in the axial direction of the spindle. A first cam and a second cam are provided on the rotary cam member and the clutch cam member, respectively, facing each other in the axial direction of the spindle. The first cam and the second cam cause the clutch cam and weight member to repeatedly move toward and away from the rotary cam member as the spindle is rotated causing the spindle to vibrate in the axial direction. The ratio: ##EQU1## determines the intensity of vibrations transmitted to the hands of an operator.

Abstract: A gear housing is arranged at or by the center of a main body housing of a chain saw and a handle housing extends backward therefrom. A motor housing is formed on the left side of the gear housing perpendicularly. A support member and a cover are attached on the right side of the gear housing. A guide bar extends forward from the main body housing and the guide bar retrains an endless saw chain therearound. The handle housing includes a trigger beside a connecting portion between the handle housing and the gear housing. A battery is disposed in a detachable manner at a rear end of the handle housing.The center of gravity of the chain saw is located at or by the trigger of the handle housing.

Abstract: A blade mounting device is operable for mounting a blade on a movable member of a cutting member which is moved in a predetermined motion for a cutting operation. The blade mounting device includes a pair of claws mounted on the movable member and operable by an operator between a closed position for clamping the blade and an open position for releasing the blade. A first and a second thread mechanism are provided for converting the rotation of the actuation member into an axial movement of the actuation member relative to the movable member and for converting the rotation of the actuation member into an axial movement of the claws relative to the actuation member.

Abstract: A combination of a base attachment structure and a cutting tool, where the base attachment structure includes a connection bolt (8) inserted and movably fitted in an aperture (9a) formed in a curved plate (9) of a gear housing (2) and a cross-shaped slide aperture (11) formed in an arch-shaped projection member (10) extending from a base (7). The connection bolt (8) includes a first upper threaded portion (8a) having threads running in a first direction to form a left-handed screw, and a second lower threaded portion (8b) having threads running in a second direction, opposite to the first direction, to form a right-handed screw. The first threaded portion (8a) is fitted into a hole (12a) formed in a pressure plate (12), whereas the second threaded portion (8b) pierces into an aperture (13a) formed in an arch-shaped clamp plate (13) and is then screwed to a right-handed fixation nut (16).