Abstract: The device for transferring torque to a tool member in a hand tool apparatus includes a plurality of catch grooves (23) and at least one elongated locking groove (25) spaced circumferentially from the catch grooves (23) provided in the tool shaft (11) of the tool member (12); a tool holder (10) having a tool receptacle (16) provided with a receptacle cavity (17) for the tool member (12) and having at least two axially extending catch elements (24) projecting inwardly into the receptacle cavity (17) so as to be engageable with the catch grooves (25) and at least one lock element (19) guided in a radial recess (18) provided in the tool receptacle (16) spaced circumferentially from the catch elements (24) so as to be radially movable outwardly against a spring force and engageable in the at least one locking groove (25) so as to limit axial motion of the tool member (12).

Abstract: A dust-intercepting member is so mounted on a hand-held power tool as to contact a structure being acted upon around the tool element of the power tool, by a mounting arrangement which includes two hollow elongated mounting members one of which is received within the other for telescoping relative thereto while being retained against rotation with respect to the other mounting member about the common axis of the mounting members, and a helical compression spring the ends of which are respectively received in the interiors of the mounting members and urge the latter in opposite directions. The other mounting member is attached to an auxiliary hand grip which, in turn, is mounted on a cylindrical extension of the housing by a quick-release clamping arrangement. A setting ring on the inner one of the mounting members determines the depth of penetration of the tool element into the structure. A depth-determining profiled rod is displaceably and arrestably mounted on the auxiliary hand grip.

Abstract: A dust-intercepting member is so mounted on a hand-held power tool as to contact a structure being acted upon around the tool element of the power tool, by a mounting arrangement which includes two hollow elongated mounting members one of which is received within the other for telescoping relative thereto while being retained against rotation with respect to the other mounting member about the common axis of the mounting members, and a helical compression spring the ends of which are respectively received in the interiors of the mounting members and urge the latter in opposite directions. The other mounting member is attached to an auxiliary hand grip which, in turn, is mounted on a cylindrical extension of the housing by a quick-release clamping arrangement. A setting ring on the inner one of the mounting members determines the depth of penetration of the tool element into the structure. A depth-determining profiled rod is displaceably and arrestably mounted on the auxiliary hand grip.

Abstract: A rotary spindle of a drill mount has a free end provided with a thread whose angle of rise is so selected that its tangent is at least equal to the coefficient of static friction of steel on steel.