Abstract: A power driven screwdriver includes a driving mechanism interposed between the drive motor and the spindle. The driving mechanism includes a first member rotatably mounted within the housing and a second member movably mounted to the first member and driven by the driver motor. A cam mechanism is interposed between the first member and the second member and is operable for transmitting rotation of the second member to the first member and for permitting the second member to move between a first position and a second position. The second member is movable from a first position to the second position as torque transmitted from the second member to the first member increases. A frictional clutch mechanism is interposed between the spindle and the first member for transmitting rotation of the first member to the spindle. A claw clutch mechanism is interposed between the spindle and the second member and is operable to be engaged when the second member is positioned at the second position.

Abstract: A miter saw has a base on which a workpiece is placed, a miter saw unit substantially vertically pivotally mounted on the base, a motor drive supported by the miter saw unit for driving a rotary tool, and a compression spring disposed between support portions formed on the base and the miter saw unit, respectively, and extending along a path of pivotal movement of the miter saw unit at a position adjacent the fulcrum of the pivotal movement of the miter saw unit so as to normally urge the miter saw unit upwardly relative to the base.

Abstract: A miter saw has a base on which a workpiece is placed, a miter saw unit substantially vertically pivotally mounted on the base, a drive supported by the miter saw unit for driving a rotary tool, a blade case mounted on the miter saw unit and partly covering the rotary tool so as to provide an exposed operational portion of the rotary tool, a safety cover pivotally mounted on the blade case for covering the exposed operational portion of the rotary tool, and an actuating link having a slot formed substantially the central portion thereof. One end of the actuating link is pivotally connected with the base, while the other end of the actuating link is engaged with the safety cover. A guide member is mounted on the blade case and is engaged with the slot of the actuating link.

Abstract: A power driven screwdriver includes a housing, a drive motor mounted within the housing, and a main gear rotatably driven by the drive motor. A spindle is axially movably supported within the housing and has a driver bit secured thereto. The spindle has a groove formed in the rear end thereof. A claw clutch mechanism is provided and is actuated by axial movement of the spindle so as to transmit and disconnect the rotation of the main gear to the spindle. The claw clutch mechanism includes a fixed clutch member formed on the main gear and a movable clutch member mounted on the spindle adjacent the rear end thereof. The movable clutch member has a groove formed in the forward end thereof in opposed relation to the groove of the spindle. One of the grooves of the spindle and the movable clutch member is configured to form an axially inclined groove. Engaging means is interposed between the groove of the spindle and the groove of the movable clutch member.

Abstract: A process and an apparatus for recovering heat from a finely to coarsely divided hot material, such as carbide crushed on solidification, which contains particles and lumps of varying sizes. The hot material is separated by a classifier into a portion of lumps and a portion of particles, and the lump portion is cooled in a cooling bunker with a stream of cooling gas while the particulate portion is cooled in another cooling unit with a stream of cooling gas. The hot cooling gas resulting from the cooling is fed to a heat exchanger in which the gas is subjected to heat exchange with a working fluid for a turbine coupled to a power generator or the like. The heat exchanger is connected to the cooling bunker and unit by a closed circulating channel.