RETENTION KNOB FOR TOOL HOLDER

摘要

A retention knob for use with a tool holder that is less prone to distorting a tapered tool holder surface, especially if it is over-tightened. The retention knob includes a knob head, a flange engageable with an end of a tool holder shank, a pilot segment receivable by the counter bore defined by said tool holder shank and a threaded segment spaced from said flange by an undercut segment. The threaded segment is configured so that it has a length that is substantially the minimum length required to achieve maximum thread holding strength. The undercut segment is configured to space the threaded segment from its head so that a distal end of the threaded segment is substantially near the bottom of the tapered bore forming part of the tool holder. With the disclosed construction, an upper portion of the threaded tool holder bore is not engaged by the threaded segment. The threaded segment has balanced threads which is achieved by locating the lead-in of the thread 180° from the lead-out of the thread. Chamfer angles at the lead-in and lead-out of the threaded segment are controlled to be the same or substantially similar.

主权项

1. A retention knob for use with a tool holder, comprising:
a) a retention knob head engageable by a spindle and a retention knob flange abutably engageable with a driven end of a tool holder; b) a pilot section receivable by a counter bore in said tool holder; c) a threaded segment engageable by a threaded bore defined by said tool holder, said threaded segment spaced a predetermined distance from said pilot section by an undercut segment; d) said threaded segment having a length that is the minimum length required for maximum thread strength and said threaded segment being spaced by said undercut such that the distal end of said threaded segment is spaced away from an end of said threaded bore in said tool holder by a small amount to avoid binding between said retention knob in the end of said threaded bore.