Cutting by use of rotating axially moving tool – Tool-support – With tool-retaining means
Patent
1996-05-20
1998-02-10
Howell, Daniel W.
Cutting by use of rotating axially moving tool
Tool-support
With tool-retaining means
409234, B23C 900
Patent
active
057161739
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tool holder to be detachably attached to the main spindle of a machine tool and to a technique for facilitating operations of attaching and detaching the tool holder.
2. Discussion of the Background
In a machine tool such as a machining center there is provided an automatic tool changing device which allows a tool holder holding a tool to be detachably attached to the main spindle of the machine tool and to be changed for an alternative. The tool holder attached to the main spindle is bound with the main spindle by contact at one portion between a tapered bore of the main spindle and a tapered surface of the shank portion of the tool holder. The contact between the tapered bore and the tapered surface is strengthened by pulling means provided within the main spindle for axially inwardly pulling the tool holder, whereby the tool holder is firmly secured to the main spindle. The bond strength (bond rigidity) between the main spindle and the tool holder will influence the machining precision of the machine tool. If the bond rigidity is low, the contact portion cannot withstand heavy cutting work or high speed rotation thereby causing chatter or vibration and collapse or run-out of the tool to occur.
To enhance the bond rigidity, the pulling force of the pulling means is required to increase. However, the increase in the pulling force of the pulling means is limited.
Known as a tool holder adapted to enhance the bond rigidity without increasing the pulling force is that described in, for example, Japanese Utility Model Publication No. SHO 63-53605.
This conventional tool holder comprises a sleeve to be fitted into the tapered bore of the main spindle of a machine tool, a shank portion inserted into the sleeve so as to be axially movable relative to the sleeve, a flange portion formed integrally with the shank potion and adapted to abut an end face of the main spindle, and an elastic member interposed between the flange portion and the sleeve. Used as the elastic member is a one-piece rubber elastic member shaped annular around the shank portion or a disc spring assembly in which a plurality of disc springs are combined as alternately orienting reverse to each other.
The conventional tool holder is detachably attached to the tapered bore of the main spindle of the machine tool by causing an arm of an automatic tool changing device to grip a circumferential groove portion formed in the outer periphery of the flange portion. Upon this attachment, a tapered surface of the outer periphery of the sleeve is fitted into the tapered bore of the main spindle with a predetermined clearance defined between the end face of the main spindle and the end face of the flange portion.
The tool holder is then pulled inwardly of the main spindle by pulling means provided in the main spindle, so that the flange end face is brought into contact with the end face of the main spindle. At this time the sleeve is pressed by the elastic member to strengthen the bonding of the sleeve to the tapered bore of the main spindle. At the same time therewith, the inner diameter of the sleeve is reduced to strengthen the bonding between the sleeve and the shank portion.
Thus, the conventional tool holder is intended obtain a bond rigidity more firm than that of a tool holder of the type to be bonded to the main spindle by contact at one portion between the tapered bore and the tapered surface with an equal pulling force by making the tool holder closely contact the main spindle of a machine tool at two portions, i.e., between the tapered bore of the main spindle of the machine tool and the tapered surface of the shank portion of the tool holder and between the end face of the main spindle and the flange end face-of-the tool holder and by strengthening the bonding of the sleeve to the shank portion.
To detach the tool holder from the machine tool in order to change the tool for an alternative, an impact is made to the rear end of the shank portion in such a di
REFERENCES:
patent: 2356835 (1944-08-01), Duckett
patent: 3554080 (1971-01-01), Herrmann
patent: 4576058 (1986-03-01), Matumoto
patent: 4655631 (1987-04-01), Mitchell
patent: 4840520 (1989-06-01), Pfalzgraf
patent: 5030047 (1991-07-01), Pfalzgraf
patent: 5324050 (1994-06-01), Kanaan
patent: 5358360 (1994-10-01), Mai
patent: 5385424 (1995-01-01), Matsumoto
patent: 5507587 (1996-04-01), Matsumoto
Howell Daniel W.
Nikken Kosakusho Works Ltd.
Tsai Henry W. H.
LandOfFree
Tool holder does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Tool holder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tool holder will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2072356