Abstract: A hand-held power tool, for example a rotary percussive drill, includes a component for undergoing linear movement and a bearing support for the component. The bearing support comprises a cylinder formed from sheet metal strip with the longitudinal edges spaced to form a gap in the wall of the cylinder. By making the bearing support from a sheet metal strip and providing a gap in the cylinder wall considerable cost savings are achieved.

Abstract: A percussive drill has a bit holder, a percussive drive including a ram slidably mounted in a hollow piston, and a drive transmission for reciprocating the ram in the piston via an air cushion. The forward travel of the ram during percussive action of the drill is limited by a drill bit or an intermediate member interposed between the drill bit and the ram. A member holds the ram in a position further forward, than that attained during the above limited travel allowed the ram, when percussive action is not desired. The holding member is resilient, has a U shaped cross-section, and is entered by the ram as it moves to the further forward position, the ram then forming a seal therewith, and the member also functioning to absorb the energy of an impact by the ram.

Abstract: A power operated tool includes a prime mover, an output member and a power transmission mechanism arranged to transmit rotary motion of the prime mover to a reciprocatory output member. The power transmission mechanism includes a first member mounted for reciprocating motion, a link coupled at one end to the first member, and a second member mounted for rotation about an axis transverse to the path of reciprocating motion of the first member. The arrangement is such that rotation of the second member reciprocates the first member and also imparts a cyclic partial rotation to the first member during said reciprocation. The second member has a bore therein spaced from the axis of rotation and inclined there towards. The bore has an axis which intersects the axis of rotation at an angle of about one quarter of the angle through which the first member partially rotates.

Abstract: A tool holder has a rotatable drive sleeve adapted to receive therein a tool and having a pair of diametrically opposed slots disposed axially along part of its length. A key extends inwardly into each slot and is movable through its sot for retaining and rotatably driving the tool. The slots have an axial length greater than that of the keys which are slidable axially there along. A locking collar, having an internal surface diverging progressively outwardly over at least a portion of its length in the axial direction, encircles the sleeve and is movable axially in one direction for locking the keys in engagement with the tool, and in the opposite direction to allow disengagement of the tool. The action of the divergent surface portion on the keys enables the keys to be locked in position over a range of inward penetrations to accommodate tools having driving recesses of different depths.

Abstract: There is disclosed an easily demountable brush assembly for electric motors utilized in portable electric tools. The assembly includes brush units which when removed from an open end of the motor casing provides ready access to the brush holders for the conventional carbon brush. Each brush unit includes a non-conductive board which is mounted radially with respect to the commutator of the motor. The boards are secured within grooves formed on the inner wall of the motor casing. Finally, the open end of the motor casing is supplied with a removable cap which holds the brush units in position when the cap is secured to the motor.

Abstract: There is disclosed a combination rotary and percussive portable tool driven by an electric motor. The percussive tool includes a reciprocating cylinder having embodied therein a reciprocatable piston striker. The cylinder is mounted in a guide tube which is spring loaded by a spring positioned between an internal wall in the housing and a cap removably mounted over an opening of the housing. The opening provides access to the housing in order to remove the guide tube and spring. With the guide tube resiliently mounted in the housing, the guide tube and its interface with the housing is much less affected by the vibration and thermal conditions developed during operation of the tool. In addition, the tolerances required to mount the guide tube in the housing do not have to be kept as tight as they would have to be if a conventional mounting arrangement using welds or other rigid fastening devices were used.

Abstract: A percussive tool has a percussion mechanism driven by a linkage that combines the simplicity of a connecting rod drive with the compactness of more complex drives. A first member, which may be a crank, drives a second member, which may be a cylinder, mounted for sliding and pivotal movement in a guide. A piston is mounted for reciprocating movement in the cylinder. Rotation of the crank reciprocates the piston causing blows to be imparted to a tool piece. The tool piece is rotated as well as being subjected to percussion.