Turning – Process of turning
Reexamination Certificate
1999-05-14
2001-02-06
Tsai, Henry W. H. (Department: 3722)
Turning
Process of turning
C082S157000, C082S162000, C082S164000
Reexamination Certificate
active
06182542
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed generally to methods and apparatus for holding a cutting tool for an automatic machine tool.
2. Description of the Prior Art
Typical prior art toolholders are shown in the brochures entitled “C. J. Winter Model 108 Shavetool Holder” and “Davenport Ordering Guide - Screw Machine Tool Co., Inc.” and in U.S. Pat. No. 2,364,320 to Schlitters. A cutting tool holder using micrometer adjusting screws for lateral and longitudinal positioning is shown in U.S. Pat. No. 3,566,723 to Oborne.
A typical prior art toolholder includes a supporting roller disposed opposite the cutting tool mounting fixture. That supporting roller, however, is fixed relative to the cutting tool mounting fixture once the distance therebetween has been adjusted to determine the finished dimension of the rotating workpiece. This can lead to an improper cutting of the workpiece as illustrated in the sequential series of
FIGS. 1A-1C
.
FIG. 1A
schematically illustrates a rotating workpiece
10
prior to the same being engaged by a cutting tool.
In
FIG. 1B
a prior art toolholder
12
has engaged the workpiece
10
. The toolholder
12
is schematically illustrated and includes a supporting roller
14
, a cutting tool mounting fixture
16
, and a cutting tool
18
. The supporting roller
14
is carried by a cradle or other support structure
20
.
In
FIG. 1B
, a situation has been schematically illustrated wherein a center line
22
of the roller
14
is not exactly parallel to a top cutting edge
24
of the cutting tool
18
, or to a center line
26
of the rotating workpiece
10
.
FIG. 1B
illustrates the situation where the top edge
24
of the cutting tool
18
has been properly aligned parallel to the center line
26
of the workpiece
10
. However, upon engagement of the roller
14
with the workpiece
10
the roller
14
has slightly bent or deflected the workpiece
16
so that a reduced diameter portion
28
thereof now lies parallel to the center line
22
of roller
14
, but is no longer parallel to the top cutting edge
24
of cutting tool
18
. This causes the cutting tool
18
to make a tapered cut on the reduced diameter portion
28
, thus resulting in a defective finished part
10
as shown in
FIG. 1C
having a machined surface
30
which is tapered rather than being cylindrical as desired.
Thus, it is seen, that there is a need for a toolholder device which can overcome the problem of the prior art illustrated in
FIGS. 1A-1C
.
These same prior art toolholders also are very difficult to adjust for initial alignment of the cutting tool
18
with the workpiece
10
. The prior art toolholders include a shaft attached to a head. The shaft has a flat portion defined thereon which is engaged by two opposed machine screws which are offset from a centerline of the shaft. To adjust the rotational position of the shaft about its centerline, both screws must be adjusted. This requires the machine operator to use both hands, advancing a screw on one side and retracting the opposing screw on the other side.
Thus, there is also a need for an improved means of adjusting the initial alignment of the cutting tool.
SUMMARY OF THE INVENTION
Methods and apparatus are provided for overcoming the problems illustrated. A toolholder apparatus is provided which includes a head, a cutting tool mounting fixture attached to the head for holding a cutting tool, and a floating roller assembly pivotally mounted relative to the head, so that during cutting of the workpiece with the cutting tool, the floating roller assembly can pivot about a pivotal axis relative to the head to allow the roller assembly to align with the workpiece.
The floating roller assembly is preferably carried by a roller assembly support. The roller assembly support includes an abutment surface which limits pivotal movement thereof relative to the head of the toolholder. A resilient member is located between the abutment surface of the roller assembly support and the roller assembly so as to cushion pivotal movement of the roller and also so as to bias the roller toward a central pivotal position. The resilient member is preferably a flat sheet of elastomeric material sandwiched between the abutment surface of the roller assembly support and a second surface of the roller assembly itself.
This apparatus, and the methods of using the same, prevent distortion of the rotating workpiece due to any initial misalignment of the roller with the rotating workpiece, thereby resulting in an even cut of the rotating workpiece by a cutting tool held by the toolholder of the present invention.
In another aspect of the present invention, methods and apparatus are provided for improving the precision and ease with which the initial alignment of the cutting tool with the rotating workpiece can be accomplished. In this aspect, the toolholder includes a cylindrical shaft extending from the head assembly, and includes an eccentric cam follower lug extending transversely from the shaft. The toolholder includes a mounting block having a cylindrical bore dispose therethrough, with the shaft being received in the bore of the mounting block. A cam piece is slideably disposed within the mounting block. The cam piece is engaged with the eccentric cam follower lug so that the shaft is rotated relative to to the mounting block as the cam piece slides relative to the mounting block. A cam piece position adjuster connects the cam piece to the mounting block. This adjuster has an adjustable threaded engagement with the cam piece so that rotation of the adjuster relative to the mounting block varies the threaded engagement of the adjuster with the cam piece and slides the cam piece relative to the mounting block. Thus, by the rotation of one and only one bidirectional threaded adjuster of the toolholder, the adjustment of the alignment of the cutting tool relative to the elongated rotating workpiece can be accomplished by a human operator using only a single hand engaging the adjuster with an appropriate tool.
Thus, a first object of the present invention is the provision of methods and apparatus for holding a cutting tool for a multi-spindle bar machine.
Another object of the present invention is the provision of such methods and apparatus including a floating roller assembly which automatically aligns itself with the rotating workpiece upon engagement therewith so as to prevent distortion of the workpiece due to engagement thereof by the roller.
Yet another object of the present invention is the prevention of distortion of the rotating workpiece due to any initial misalignment of a roller of a toolholder with the rotating workpiece, thereby preventing uneven cutting of the rotating workpiece by a cutting tool which has been previously aligned with the workpiece.
Still another object of the present invention is the provision of methods and apparatus for initial alignment of the cutting tool with the rotating workpiece.
Numerous other objects, features and advantages of the present invention will be readily apparent to those skilled in the art after a reading of the following disclosure when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 2158798 (1939-05-01), Lange et al.
patent: 2323324 (1943-07-01), Hanson
patent: 2364320 (1944-12-01), Schlitters
patent: 2687664 (1954-08-01), Smith
patent: 2746332 (1956-05-01), Smith
patent: 3094024 (1963-06-01), Synk et al.
patent: 3566723 (1971-03-01), Oborne
patent: 3576145 (1971-04-01), Bernath
patent: 4986151 (1991-01-01), Horn
patent: 0703058 (1954-01-01), None
Brochure entitled “C.J. Winter Model 108 Shavetool Holder” (undated but admitted to be prior art).
Brochure entitled “Davenport Ordering Guide—Screw Machine Tool Co., Inc.” (undated but admitted to be prior art).
Brochure of Jersey Manufacturing Co. (1980).
Brochure entitled “C.J. Winter Machine 119SA & 120SA Dovetail Shavetools” (undated but admitted to be prior art).
Brochure entitled “Shaving / Dovetail Tool Type—Heavy Duty” (undated but admitted to be prior art).
Brochure
Ballew Lawrence A.
Chaffin Fred E.
Charleton Mark G.
Peterson John L.
Beavers Lucian Wayne
Peterson Tool Company
Tsai Henry W. H.
Waddey & Patterson
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