Cutters – for shaping – Rotary cutting tool – Including holder having seat for inserted tool
Reexamination Certificate
2001-11-26
2004-05-25
Wellington, A. L. (Department: 3722)
Cutters, for shaping
Rotary cutting tool
Including holder having seat for inserted tool
C407S041000, C408S083500
Reexamination Certificate
active
06739807
ABSTRACT:
BACKGROUND OF THE INVENTION
I. Field of the Invention
This invention relates to rotatable cutting tools, particularly tools having replaceable cutting blades or inserts releasably retained by clamping means in the tool body.
II. Description of Related Art
It is known to provide rotatable tools comprising a tool body and one or more replaceable blades or inserts for machining operations. An insert for these tools comprises a cutting element made of a relatively long wearing material chosen for compatibility with the material to be cut and comprising one or more cutting edges. An insert may further comprise a holder for mounting the cutting element to the tool body. A tool body for such tools comprises at least one recess for receiving a replaceable insert and the tool further comprises means for releasably retaining the inserts on the tool body. Tools of this type include drilling tools, boring tools, reaming tools and milling tools.
A particular type of rotatable tool is a tool for machining valve seats in cylinder heads of internal combustion engines, the tool having cutting inserts arrayed on the periphery of the tool and having a reaming tool for machining the valve stem guide bore. As the number of valves per cylinder have increased and overall engine dimensions have decreased, valve diameters have decreased. Consequently tools for performing valve seat machining operations are required to retain cutting blades or inserts in tool bodies having reduced diameters. Known tools for such applications, such as disclosed in U.S. Pat. No. 5,704,741, have included exchangeable cartridges for retaining replaceable cutting inserts. With the demand for smaller diameter valves, smaller diameter tools are required, reducing the tool body volume that can be consumed with blade retaining devices.
FIGS. 1
a
and
1
b
illustrate one known tool wherein the replaceable blades are retained in recesses in the tool body by clamping screws. In
FIG. 1
a
, replaceable blades
112
and
114
are retained in recesses of tool body
110
. As shown with respect to replaceable blade
112
, clamping screws
116
are transverse to recess
118
(
FIG. 1
b
) and are threadably engaged with tool body
110
. With replaceable blade
112
in place in recess
118
, advance of clamping screws
116
into tool body
110
clamps blade
112
(shown dashed in
FIG. 1
b
) against a side wall of recess
118
. As shown in
FIG. 1
a
, plural screws are used and are spaced apart to distribute the clamping forces over the length of the blade to improve resistance of the blade to displacement from cutting forces and from distortion from clamping forces.
FIGS. 1
c
and
1
d
illustrate an alternative known clamping arrangement for retaining replaceable tools in a tool body. In
FIG. 1
c
, replaceable blades
122
and
124
are retained in recesses of tool body
120
. As shown with respect to replaceable blade
122
, wedges
128
are held in recesses
130
adjacent blade receiving recess
132
(
FIG. 1
d
) by screws
126
. Screws
126
are threadably engaged with tool body
120
. With replaceable blade
122
in place in recess
132
, advance of screws
126
into tool body
120
advances the forward edges of wedges
128
to clamp blade
122
(shown dashed in
FIG. 1
d
) against a sidewall of recess
132
. Each of wedges
128
serves to distribute the forces from each of screws
126
over larger portions of blade
122
than would be done by the screws alone as in the arrangement of
FIG. 1
a
. However, while larger wedges would provide improved distribution of forces, large wedge receiving recesses, such as recesses
130
are not desirable because of the attendant weakening of the tool body.
In light of the shortcomings of the known clamping means as illustrated in
FIGS. 1
a
and
1
c
, there remains a need for improved clamping means for replaceable blades in rotating tools.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a rotatable cutting tool body for releasable retention of at least one replaceable cutting blade wherein the tool body includes an elastically deformable clamp for each such blade, the clamp operable to apply a clamping force to a blade to releasably retain the blade in the tool body.
It is a further object of the present invention to provide a rotatable cutting tool body for releasable retention of at least one replaceable cutting blade wherein the tool body includes an elastically deformable clamp for each such blade, the clamp being operable to apply a clamping force to releasably retain a blade and comprising a leaf integral with the body and a clamping means for deforming the leaf.
It is a still further object of the present invention to provide a rotatable cutting tool having at least one replaceable cuffing blade releasably retained thereon wherein the tool body includes an elastically deformable clamp for each such blade, the clamp being operable to apply a clamping force to releasably retain a blade.
It is a still further object of the present invention to provide a rotatable cutting tool having at least one replaceable cutting blade releasably retained thereon wherein the tool body includes an elastically deformable clamp for each such blade, the clamp being operable to apply a clamping force to releasably retain a blade and comprising a leaf integral with the body and a clamping means for deforming the leaf.
Further objects and advantages of the invention shall be made apparent from the accompanying drawings and the following description thereof.
In accordance with the aforesaid objects the present invention provides a rotatable cutting tool comprising a cutting tool body having at least one recess for receiving a replaceable insert. The recess has a wall defined by a deformable leaf isolated from the tool body except at the base of the leaf by an isolating channel in the tool body. The tool further comprising adjustable clamping means for elastically deforming the leaf to releasably retain a replaceable insert in the recess.
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Brow Larry A.
Grech Kenneth A.
Robinson James J.
Burns Doane , Swecker, Mathis LLP
Valenite LLC
Walsh Brian D.
Wellington A. L.
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