Abstract: A chuck for receiving a tool shank of a boring tool and including radially displaceable engagement members (5) formlockingly engageable in the radial recesses (3) formed in the clamp region of the tool shank, an axially displaceable control sleeve (6) for radially displacing the engagement members between their engagement and release positions, and a resilient holding member (8) arranged between the control sleeve (6) and the clamp region of the tool shank and having a detent element (9) for preventing displacement of the control sleeve into its locking position (7) from its release position (10) into which the control sleeve was displaced upon insertion of the boring tool.

Abstract: An electrical hand operated tool driving device (1) for at least partially rotationally driving a tool has a tool chuck (3), at the front end of a housing (2) along with an operating handle (4) for an operator's hand (11), with the handle located adjacent to the tool chuck. A bearing surface (8), for supporting the electrical hand operated tool driving device (1) on the forearm associated with the operator's hand (11), is positioned in the rear end region of the housing (2) spaced from the tool chuck (3).

Abstract: A chuck for drilling and chiseling tools and including a receiving sleeve at least one through-opening formed in a sleeve wall at least one locking member supported for a limited pivotal movement about a pivot axis, which extends substantially perpendicular to a longitudinal axis of the receiving sleeve, and projecting at least partially into the through-opening (12) of the sleeve with the locking member (6) extending in its locking position through the through-opening (12) into a receiving sleeve inferior, a guide ring surrounding the receiving sleeve and at least partially overlapping the locking member (6) in its locking position, preventing the locking member (6) from pivoting into its release position and an actuation sleeve (7) displaceable in a direction opposite to an operational direction of the tool against a spring-biasing force for enabling pivoting of the locking member (6) into the release position, with the locking member (6) being pivotally connected with the actuation sleeve (7).

Abstract: In a hand-held tool having a tool holder for receiving a variety of tool bits, a probing device is provided for checking the surface configuration of the shank of a tool bit inserted into the tool holder. The probing device includes at least one control element arranged to move radially inwardly through an opening in the tool holder. If the control element moves radially inwardly into an axially elongated recess in the tool bit shank, it moves out of stopping engagement with a slide permitting the slide to move relative to the control element and initiating a switching operation for changing the driving action of the hand-held tool.

Abstract: A hand-held device, such as a hammer drill, has a replaceable axially extending holder for a working tool. The device includes a sensor and a signal transmitter for adjusting its operating characteristics. The holder has through openings containing locking elements and control elements. The locking elements and control elements are radially displaceable within the through openings by a locking sleeve. The position of the locking sleeve in the axial direction of and relative to the holder determines the cooperation of the sensor and the signal transmitters.

Abstract: A hand-held device with a holder for a working tool has a sensing mechanism for automatically initiating different operating modes. Different configurations of working tools inserted into the holder can be sensed by sensing elements in the form of balls. The balls cooperate with pivotal levers and a sensor for producing switching signals for initiating a switching operation.