Tool holder clamping means

Claim 1

A tool holder locking means comprising in combination: (a) a housing adapted to be securely fixed to a machine tool and having a bore therein; (b) a hollow tapered tool holder insert in said bore for receiving a tool holder, said insert having a face end abutting said housing and having a hollow cylindrical projection positioned concentrically in said bore and defining an annular space therebetween; (c) a ball thread device comprising inner and outer nesting cup shaped races positioned concentrically in said bore adjacent said insert and with the outer race constrained from axial motion, said inner and outer races having complementary thread grooves on their adjacent surfaces having a plurality of drive balls therein whereby rotation of said outer race drives said inner race axially; (d) a hollow cylindrical coupling member affixed to said inner race and extending into the hollow cylindrical projection of said insert in coaxial relationship, said coupling member having means for axial reciprocating motion therein, said coupling member having a transverse aperture therein adjacent its inner end, a ball means loosely fitting in said aperture and adapted to occupy a first low position where the ball means rests on the bore of the insert while remaining in said aperture, and to occupy a second elevated position by means of a step shoulder on the end of said insert which underlies said aperture when the coupler is moved axially in one position; (e) a detent member affixed to said insert and coaxially projecting into said coupling member and engaging said ball means to be retained thereby; (f) spring means in said housing bore and coaxially positioned in said annular space between said insert projection and said housing bore, said spring means engaging said insert at one end and engaging said inner race at the outer end; and (g) drive means on said outer race and adapted to rotate said outer race so that said inner race moves axially to compress said spring means while at the same time moving said coupling member axially so that said detent ball drops in its aperture to permit withdrawal of said detent from said coupling means and said tool holder from said insert.