Abstract: A device on machine tools for transmitting a rotational and/or percussive movement to a tool (22) has two or three rotational drivers (14) which are arranged so as to be symmetrical with respect to rotation. The rotational drivers (14) are stepped and flank parts (16) extending radially to the center axis (15) alternate with guide portions (17) extending along a cylindrical outer surface. Locking members (20) which engage in depressions (28) at the tool (22) are arranged in the region of the rotational drivers (14) for the axial locking of the tools (10). With the tool holder (10) according to the invention, tool shafts having diameters between 8 and 12 mm can be clamped without converting or modifying the tool shafts. Good true running characteristics can be achieved in spite of the stationary rotational drivers (14).

Abstract: A device on machine tools for transmitting a rotational and/or percussive movement to a tool (22) has two or three rotational drivers (14) which are arranged so as to be symmetrical with respect to rotation. The rotational drivers (14) are stepped and flank parts (16) extending radially to the center axis (15) alternate with guide portions (17) extending along a cylindrical outer surface. Locking members (20) which engage in depressions (28) at the tool (22) are arranged in the region of the rotational drivers (14) for the axial locking of the tools (10). With the tool holder (10) according to the invention, tool shafts having diameters between 8 and 12 mm can be clamped without converting or modifying the tool shafts. Good true running characteristics can be achieved in spite of the stationary rotational drivers (14).

Abstract: A device for transmitting a rotary and/or percussive movement to a tool is formed in such a way that the associated tools having three grooves arranged in rotationally symmetrical fashion can likewise be clamped in drill chucks having three chuck jaws. In addition, the tool is to have the limited axial mobility required when hammer drilling or chiselling. For this purpose, the device is equipped with three rotary driving elements arranged in a location hole and projecting inwards. The rotary driving elements are arranged in rotationally symmetrical fashion, are of equal width and have flanks which extend approximately parallel to one another. One of the rotary driving elements is longer in the radial direction than the other two in order to guarantee positionally correct insertion of the tool and satisfactory locking of a locking body in a closed groove of the tool. The rotary driving elements are fixed immovably in the location hole.

Abstract: A device for driving-in stitches, has a magazine for receiving stitches of different widths and having a housing for accommodating stitches, a slider insertable in the housing and having a guiding rail for guiding stitches and a shooting passage with an opening, an end plate mounted on the casing and a stripping plate mounted on the slider and limiting the opening of the shooting passage. The stripping plate is formed as an angular piece with a first leg which limits the shooting passage and a second leg extending substantially perpendicularly to the first leg and abutting against the slider.

Abstract: A hand held power tool has a rotatable spindle, a tool holder arranged on the spindle, a tool inserted in the tool holder, locking members fixing the tool holder with the spindle and engaging both in the tool holder and the spindle, a rotatable ring holding the locking members in its locking position and provided with depressions for receiving the locking members not locking position, and a gripping sleeve connected with the ring and operating simultaneously as an actuating member for unlocking the tool inserted in the tool holder.

Abstract: A chuck for use in a percussion drill or the like has a unit for securing the chuck jaws against unintentional loosening during operation. The securing unit moves from an unlocked position in which a tool can be received by the chuck jaws to a locked position automatically for drilling operations without the use of a key. The securing unit includes a first surface (22) upon which a sliding member (21) is slidable to be received in a recess (26) during the shaking caused by drilling, so that coupling members (15, 19) between a securing sleeve (17) and a clamping sleeve (13) engage with one another.

Abstract: A power hammer drill includes a tool holder and an air cushion striking mechanism for driving a tool and including a striker, a reciprocating piston for displacing the striker, and an axially displaceable guide tube for guiding the piston. A device for holding the striker in a forward position thereof adjacent to the tool holder in an idling condition of the hammer drill is provided in the hammer drill. The device has a guide element fixed in the drill housing for guiding the guide tube. The guide tube has a control opening for venting the air cushion and which remains in open or closed condition dependent on axial position of the guide tube.

Abstract: A device on hand machine tools is suggested for the transmission of torque to percussion drilling tools in which at least two rotary driving grooves open out at the end of the tool shaft and strip-shaped rotary drivers of the tool shaft engage in these rotary driving grooves and include assigned flanks, which are at least approximately planar, and in which locking members are arranged in the tool receptacle and cooperate with two recesses in the tool shaft which are closed on both sides and lie diametrically opposite one another. In order to avoid incorrectly reversed insertion of tools with driving grooves which are worn out due to intensive wear, the latter are distributed along the circumference of the tool shaft in such a way that two rotary driving grooves can in no case lie diametrically opposite one another.

Abstract: A motor-driven hand drill includes a housing, in which between a motor and a drill receptacle, a safety coupling for limiting a torque, applied to a drill, is positioned. For specific conditions, for example for drilling in armoring iron, the torque applied to the drill must be increased. The drill is provided with an electro-magnetic device which is operatively connected to the safety coupling to adjust the limiting torque applied to the drill. The magnetic device is actuated by means of a pushbutton positioned in the same gripping region as the pushbutton for actuating an electric motor of the drill to switch the same on and off.

Abstract: An arrangement for torque transmitting to impacting and/or drilling tool has a chuck provided with clamping jaws which in the region of their contact with a tool shaft have a toothing including a plurality of teeth which extend parallel to an axis of the chuck and engage with a toothed portion of the shaft end.

Abstract: A power driven hammer drill includes a percussive mechanism connectable to driving gears via a clutch. A pressure amplifying lever system is arranged between a movable part of the clutch and shiftable guiding means for a work tool to apply an amplified pressure on the clutch when the work tool is pressed against a workpiece.

Abstract: A hammer drill is provided with a clutch whose movable part is firmly connected to an axially displaceable drum which supports a wobbling disc driving a percussive mechanism for striking a work tool. The axially fixed clutch part is rotated by driving motor and is backed-up by a housing of the drill. Retroacting forces from the percussive mechanism are transferred via the drum onto the movable clutch part so that the engagement of the clutch is reinforced at the moment when the compression generated by percussive mechanism is maximum. When pressure applied on work tool is relieved, a separating spring disengages the clutch and braking surfaces on the drum limit its axial displacement and brake the rotation of the wobbling disc.

Abstract: A power impact device, particularly for fasteners, comprises a propelling passage, a driver movable in the propelling passage, a magazine for fasteners and crossing the propelling passage, and an abutment arranged for positioning a set of fasteners for separating a frontmost fastener by the driver, the abutment being formed so that only a part of the cross-section of the set of fasteners is supported and so that it is displaceable relative to the propelling passage, the driver having a cross-section which deviates from a cross-section of the propelling passage over a fit tolerance so as to allow narrowing of the propelling passage without preventing movement of the driver and reducing its thickness.

Abstract: A power tool, particularly a hand-held power tool, has a striking mechanism with a striker transmitting impact energy to a tool, a drive operative for actuating the striker through an air cushion, and a heat insulating element which is associated with the striker and insulates the same from heat generated in the air cushion during the operation of the power tool. The heat insulating element may simultaneously be formed as a mechanical buffer.

Abstract: In a drill hammer a motor driven striking mechanism is provided with two air cushions of changeable volumes, through which impact energy is transmitted from the motor to a reciprocating striker which in turn transmits the energy to a tool of the drill hammer. When the striker moves in the direction towards the tool both air cushions act on the striker whereas when the striker moves away from the tool only one of two air cushions acts on the striker.

Abstract: In a drive-in apparatus for driving fasteners such as clips, nails, tacks, staples and the like in a workpiece, a solenoid for actuating impact blade which ejects the fastener is movably arranged in the apparatus housing. The solenoid includes an exciter coil formed with a central opening in which a cylindrical armature connected to the impact blade is magnetically accelerated in forward direction and returns to the starting position by a resetting spring. The exciter coil is also movably guided within the housing and spring biased in the forward direction by another biasing spring having a progressive elasticity characteristic. Depending on the steepness of the characteristic line of the second biasing spring, the backstrokes of the apparatus and the force necessary for tacking operation can be adjusted in broad range.

Abstract: A hammer drill has a housing provided with a tool chuck in which a tool is to be mounted. A drive is provided which is capable of rotating and/or axially impacting the tool chuck. This drive includes a piston reciprocable in axial direction of the tool chuck, a drum rotating on a shaft extending parallel to the direction of reciprocation of the piston and provided with a circumferentially extending cam track, and a transmitting arrangement which travels in part in engagement with the cam track and which has another part connected with the piston to reciprocate the same.

Abstract: A tool chuck for a hammer drill has an inner sleeve and an axially slidable outer sleeve concentrically surrounding the inner sleeve. The inner sleeve has an open leading end adapted to receive a shank of the tool. The shank is clamped in the inner sleeve with a snap action in response to insertion of the shank through the open end. Torque and/or axial impact are selectively imparted to the tool chuck from a drive of the hammer drill. The tool shank is formed with a radially outwardly opening recess closed at both axial ends and shaped to receive a tool-holding element and with at least one axially extending groove. A formation is formed in the inner sleeve which is engageable with the axially extending groove for torque transmission. A ring is positioned between the outer sleeve and the inner sleeve. The ring is movably biased by a spring in axial direction and is provided with a projection engageable with the tool-holding element when the latter is moved outwardly of the recess.

Abstract: An impacting drill is equipped with an air cushion impacting mechanism and with a tumbling mechanism which is operative for reciprocating the impacting mechanism. The tumbling stroke of the tumbling mechanism and thus the reciprocating stroke of the impacting mechanism is adjustable from zero to a maximum. The tumbling mechanism includes a hub body which is mounted on a holding body rigid with a rotatable shaft. The holding body is centered on an adjustment axis which encloses an acute angle with the axis of the shaft. The hub body is mounted on the holding body for angular displacement about the adjustment axis with attendant adjustment of the tumbling range. Coupling elements connect the hub body with the holding body in the respectively selected angularly displaced position of the hub body on the holding body.

Abstract: A device on hand machine tools is suggested for the transmission of torque to percussion drilling tools in which at least two rotary driving grooves open out at the end of the tool shaft and strip-shaped rotary drivers of the tool shaft engage in these rotary driving grooves and include assigned flanks, which are at least approximately planar, and in which locking members are arranged in the tool receptacle and cooperate with two recesses in the tool shaft which are closed on both sides and lie diametrically opposite one another. In order to avoid incorrectly reversed insertion of tools with driving grooves which are worn out due to intensive wear, the latter are distributed along the circumference of the tool shaft in such a way that two rotary driving grooves can in no case lie diametrically opposite one another.