Working tool holder for a drilling or chiseling device

A working tool holder for a drilling or chiseling device and for securing a working tool, said working tool holder comprises an axially extending holder sleeve having a first end and a second end spaced apart in the axial direction with an axially extending tool opening for a shaft of a working tool extending from the first end thereof toward the second end, at least an axially extending section of said tool opening being conically tapered inwardly toward the holder sleeve axis in the direction toward the second ends, pins mounted in said holder sleeve are movable generally radially inwardly and outwardly relative to said opening, said pins extending chordally relative to said opening, radially inwardly directed axially extending projections extending into said opening for engagement within corresponding axially extending grooves in an insertion shaft of a working tool, said working tool having recesses for receiving said pins, and an actuating sleeve located around and axially displaceable relative to said holder sleeve between a first position without a working tool in the holder opening and a second position with a working tool secured in the holder opening, with said actuating sleeve being movable in the direction from the second end toward the first end of said holder sleeve, means in said actuating sleeve for spring biasing said pins into engagement with said recesses of said working tool and for moving said pins out of engagement with said recesses of said working tool against the spring biasing, wherein the improvement comprises that said actuating sleeve is rotatable about the axis of said holder and has a first end adjacent the first end of said holder sleeve and a second end adjacent the second end of said holder sleeve, connecting means on said actuating sleeve and said working tool for securing said working tool within said holder sleeve, said connecting means comprises an internal thread in said actuating sleeve located adjacent the first end thereof and an external thread on said insertion shaft, and said internal thread being screwably engageable with said external thread.