Abstract: The spindle neck of a manually held power drill is to be releasably secured in a slotted sleeve of an auxiliary tool unit. For this purpose a tensioning band is provided which surrounds the sleeve and tensions the same about the spindle neck, and a manually operable tensioning-lever arrangement is provided which requires no use of tools and which serves for rapidly engaging and disengaging the tensioning band.

Abstract: A chuck for hammerdrills and the like is provided with a chuck body; a plurality of jaws on said chuck body for engaging and holding a tool bit; and means connected to said jaws for adjusting the engagement of said jaws with the tool bit, said means comprising a guide sleeve having a main portion with an outer and inner surface, said main portion defining a central axis therethrough, a toothed gear encircled by said sleeve and having a circumferentially extending groove having a roughened surface facing the inner surface of said sleeve, said sleeve including at least one inwardly offset locking portion having an outer and inner surface which are inwardly offset with respect to the main portion of said sleeve, said inwardly offset portion projecting into said groove.

Abstract: A chuck body has one end for connection to a power tool, and another end from which a plurality of jaws project. A sleeve turnably surrounds the body and jaws and is operative, when turned in one direction, for moving the jaws inwardly towards one another into engagement with a tool bit that is located between them. A plate spring is mounted at the one end of the body and has a circumferential marginal portion which engages and frictionally locks the sleeve when the latter is turned in the aforementioned one direction.