초록 ▼

A simple, strong and fast acting tool retention subsystem is intended for both original equipment and retrofit applications in machining centers with automatic tool changer systems. A machining center incorporating the invention is described. The invention is compatible with ANSI standards for spind

A simple, strong and fast acting tool retention subsystem is intended for both original equipment and retrofit applications in machining centers with automatic tool changer systems. A machining center incorporating the invention is described. The invention is compatible with ANSI standards for spindles, tapered tool shanks and knobs, and is configured to eliminate the tool chatter and tool shank taper unseating and release commonly occurring in conventional spring actuated tool retention subsystems when spiral fluted cutters are used. The tool shank is positively jam locked by a rotary bolt actuator means that generates a very high value of axial pre-load tension, comparable to that which was furnished by the very successful historic manual draw-in bolt retention subsystem used in milling machines. A bi-directional free wheeling impact motor drives the rotary bolt actuator means between open and closed positions of a maximally strong collet. Positive seating of the tool shank in the spindle nose taper is assured by the extremely high pre-load tension applied to the knob, which is supplied by the mechanical strain of the steel of the jam locked mechanism and the supporting spindle structure. Thus the tool retention is limited only by the yield strength of the materials and not by the bias of any coil or belleville spring, as is the current practice in the machining center industry.

대표청구항 ▼

A positive locking tool shank retention mechanism, for use in a machine tool spindle having a female tapered entrance in its nose, fully compatible with the automatic tool changing systems of computer numeric controlled machining centers, and for other applications, with rapid shank engagement and r

A positive locking tool shank retention mechanism, for use in a machine tool spindle having a female tapered entrance in its nose, fully compatible with the automatic tool changing systems of computer numeric controlled machining centers, and for other applications, with rapid shank engagement and release to allow quick changing of tools that are mounted in mating male tapered tool shanks having retention knobs, and featuring such positive axial tool retention force that said mechanism cannot be overcome by the severe axial counter forces that are generated by spiral cutting tools when operated at the full machine tool rated spindle horsepower, in order to raise machine tool productivity by eliminating the machine tool operator\s problems involving taper unseating, vibration and chatter, damage to work and machines, tool loss, extra down time with added maintenance, and lowered operator safety, that are caused by said spiral cutting tools which universally generate sufficient axial forces to readily overcome the limited bias tool shank retention force of the current conventional standard of the industry belleville and other spring actuated tool shank retention systems when operated at a spindle driving power level considerably lower than the rated machine spindle horsepower, comprising: collet means for (A) surrounding and seizing, in the open position of said collet means, one of said knobs presented into said spindle nose entrance within reach of said collet means, and for (B) pulling, into the closed position of said collet means, said attached tapered tool shank body to a tight positive seating in said spindle nose taper; and rotary bolt actuator means, including two threaded portions, one portion being threadably connected to the spindle and the other portion being threadably connected to said collet means, whereby rotation of said rotary bolt actuator means causes motion of said collet means with respect to said spindle, for threadable positive axial (A) bi-directional displacement of said collet means relative to and within said spindle between said open and closed positions, and for (B) jam locking of said rotary bolt actuator means under high pre-load axial tension in said closed position, and for (C) springless retention of said tool shank in said closed position, wherein said knob and attached tool shank body are held under said high pre-load axial tension within said spindle, and wherein said tension is supplied by the mechanical strain of the materials of the jam locked structure of said mechanism and said spindle supporting said tension and limited only by the yield strength of said materials; and motor means for (A) selective bi-directional driving of said rotary actuator means between said open and closed positions, and for (B) providing said threadable jam locking under said high pre-load tension.