Abstract: A hammer drill (1) includes a lock plate (35) forward of a boss sleeve (13) and a swash bearing (14) which cooperates with the boss sleeve to convert the rotation of an intermediate shaft (5) on which the boss sleeve is mounted. The lock plate is mounted on the boss sleeve and selectively engages claws (23) of the boss sleeve (13) in a manner that permits its integral rotation with and axial slide with respect to the boss sleeve. The lock plate is additionally biased in the forward direction by a coil spring (38) so that when a clutch (19) is shifted forward in a drill mode, the lock plate also moves forward into engagement with a stopper (39) secured to an inner housing (4), preventing inadvertent rotation of the boss sleeve.

Abstract: A hammer drill (1) includes a lock plate (35) forward of a boss sleeve (13) and a swash bearing (14) which cooperates with the boss sleeve to convert the rotation of an intermediate shaft (5) on which the boss sleeve is mounted. The lock plate is mounted on the boss sleeve and selectively engages claws (23) of the boss sleeve (13) in a manner that permits its integral rotation with and axial slide with respect to the boss sleeve. The lock plate is additionally biased in the forward direction by a coil spring (38) so that when a clutch (19) is shifted forward in a drill mode, the lock plate also moves forward into engagement with a stopper (39) secured to an inner housing (4), preventing inadvertent rotation of the boss sleeve.

Abstract: A power-driven hammer has a tool holder a middle bore portion which is supported inside a housing and urged backward by a compression spring. The rear end of a large bore portion of the tool holder is slidably fitted into a spline ring which is secured to the front end of a middle housing. Spline grooves are formed in the inner periphery of the spline ring at its front end while spline gears are formed on the outer periphery of the large bore portion. When the spline grooves and the spline gears are engaged with each other, the tool holder, being urged backward, is locked with its rotation prohibited. This tool holder can be temporarily unlocked to allow its rotation by sliding a change ring cover forward and the tool holder itself, thereby disengaging the large bore portion from the spline ring.

Abstract: There is provided a power-driven striking tool including: a casing; a tool holder rotatably supported inside the casing and having a front end to which a tool bit is attached; and an operating member fitted around the tool holder and exposed to the outside of the tool so as to be manually slidable in the axial directions of the tool holder and integrally rotatable with the tool holder. The operating member is biased rearward by a compression spring along the axis of the tool holder into contact with the casing. The tool further includes first teeth provided on the operating member where it comes into contact with the casing and second teeth provided on the casing where it comes into contact with the operating member. When the operating member is brought into contact with the casing, the first and second teeth engages each other to prevent the operating member and thus the tool holder from rotating relative to the casing.

Abstract: The present invention realizes effective recoil reduction and idling strike prevention with a minimum constitution. In a tool holder (6), a thermal-resistant O-ring (22) is arranged between two steel washers (21,23) near the joint to the barrel (5). The O-ring (22) has a cross-sectional diameter of approximately 7 mm. The inner diameter of the O-ring (22) is made slightly greater than the diameter of a cylindrical portion (19b) formed at the rear of an intermediate element (19) and slightly smaller than the diameter of a flange (19a) formed at the rear of the cylindrical portion (19b). Likewise, the inner diameter is made slightly greater than the diameter of a recess (18b) of a striking member (18) formed in front thereof and slightly smaller than the diameter of a flange (18a) formed in front of the recess (18b).

Abstract: The invention provides an improved intermediate housing incorporated in a power driven hammer drill, which is light in weight, easily and safely handled, and uncostly manufactured. The intermediate housing of the invention includes a bearing member and a cylindrical piston housing member which are integrally composed of a synthetic resin having high tenacity and excellent heat resistance and wear resistance. The intermediate housing further includes a plurality of ribs radially extending from the piston housing member to give a sufficient strength durable to a stress applied onto the piston housing member. In the intermediate housing thus constructed, the bearing member has at least one opening for feeding an air flow generated by a fan while the piston housing member includes at least one air conduit for circulating the air flow. This structure efficiently prevents overheat and thermal deformation of the piston housing member and the bearing member in continuous operation of the hammer drill.

Abstract: A portable reciprocating saw includes a tool housing, an electric motor enclosed in the tool housing and having an output shaft, an elongated slider for supporting a saw blade, and motion converting means mounted in the tool housing for converting the rotation from the electric motor into a reciprocating motion of the slider in longitudinal direction. The motion converting means includes a bevel gear meshing with the ouptut shaft of the electric motor and rotatable about an axis inclined to a plane transverse to the longitudinal direction of the slider, a slider block mounted on the slider and having a guide groove formed on a lower surface thereof in a direction transverse to the longitudinal direction of the slider, and an eccentric pin mounted on the bevel gear at a position eccentric from the center of the bevel gear and loosely fitted in the guide groove of the slider block.

Abstract: Casting band heater for molten metal continuous casting apparatus, wherein a casting band forming one of the mold surfaces is preheated to improve the operational life of the casting band. The apparatus also assures a dry band to avoid steam explosions and gas entrapments. The band heater includes an efficient burner and a band enclosure which can be opened for band changes.