Cutters – for shaping – Rotary cutting tool – Including holder having seat for inserted tool
Reexamination Certificate
1999-06-21
2001-01-23
Tsai, Henry W. H. (Department: 3722)
Cutters, for shaping
Rotary cutting tool
Including holder having seat for inserted tool
C407S043000, C407S046000, C407S053000
Reexamination Certificate
active
06176648
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to face milling cutters and cutter bodies thereof, and more specifically to a face milling cutter having a groove for a cartridge preventing the cartridge type holder for an insert from flying out under centrifugal force and a cutter body thereof.
2. Description of the Background Art
In most cases, a wedge is used for clamping an insert in a face milling cutter. In this case, the insert is inserted into a groove which is formed both in front and side surfaces of a cutter body, so that it is held in place only by friction force. In the conventional method, however, if strong centrifugal force acts on the insert due to the high speed rotation of the cutter body, the insert is often shifted during cutting operation. In an extreme case, the insert may even fly out of the groove.
FIG. 7
is a diagram shown in conjunction with a typical method of fixing the insert in the conventional face milling cutter. In the conventional face milling cutter shown in
FIG. 7
, a wedge is used to prevent flying out of the insert under centrifugal force.
Referring to
FIG. 7
, a groove
101
and a wedge groove
103
are formed in a cutter body
100
. An insert
104
is arranged in edge groove
101
. A wedge
102
is pressed and fitted in wedge groove
103
.
It is difficult to form with accuracy an acute angle corner
700
of edge groove
101
and an acute angle corner
600
of wedge groove
103
in which wedge
102
is press fitted as vertical angles thereof are acute. Thus, insert
104
and edge groove
101
as well as wedge
102
and wedge groove
103
are not provided with sufficient accuracy in shape, whereby positional accuracy of the edge and stability of clamping are decreased. As a result, insert
104
may be slightly shifted under centrifugal force developed during high speed rotation of cutter body
100
. Further, wedge
102
may become loose due to vibration during cutting, so that insert
104
is slightly shifted. Thus, the conventional face milling cutter lacks in reliability.
To solve this problem, a mechanism having a groove in a cutter body to receive an insert which is clamped by a wedge is proposed in Japanese Patent Laying-Open No. 5-138423.
FIGS. 8 and 9
are diagrams shown in conjunction with a conventionally proposed method of fixing the insert in the face milling cutter. Here, the grooves are formed in cylinder and polyhedron shapes in
FIGS. 8 and 9
, respectively.
Referring to
FIG. 8
, a groove
151
is formed generally in parallel to an axial center of cutter body
100
by cutting cutter body
100
. An insert body
152
has a face
153
. An edge (not shown) is connected to insert body
152
with a prescribed angle to face
153
. A wedge
154
is fixed to cutter body
100
by a double screw
155
while abutting against face
153
of insert body
152
.
In this configuration, even if wedge
154
becomes more or less loose, insert body
152
would not fly out under centrifugal force because of an overhanging portion
100
a
. In addition, edge groove
151
can be easily formed simply by cutting to open a through hole in a direction of a side surface of cutter body
100
.
Referring to
FIG. 9
, in another conventional example, a groove
161
in a rectangular shape is formed by cutting cutter body
100
generally in parallel to the axial center of cutter body
100
. An insert body
162
has an inclined face
163
. An edge (not shown) is connected to insert body
162
with a prescribed angle to an abutting face
164
. A wedge
154
is fixed to a cutter body
100
by a double screw
155
while abutting against inclined face
163
of insert body
162
.
Again, even if wedge
154
becomes loose, insert body
162
would not fly out under centrifugal force because of an overhanging portion
100
a
of cutter body
100
.
In short, in the aforementioned laid open application, grooves
151
and
161
are respectively formed in cylinder and polyhedron shapes to receive insert bodies
152
and
162
, with reference to
FIGS. 8 and 9
. Insert bodies
152
and
162
are clamped with wedge
154
which is movable in a direction orthogonal to edge grooves
151
and
161
. Accordingly, movement of insert bodies
152
and
162
in a radial direction of cutter body
100
is restrained by overhanging portion
100
a
. As a result, the stability of clamping is not decreased even in the case of the high speed rotation and shifting or flying out of insert bodies
152
and
162
under centrifugal force is surely prevented, whereby stability and accuracy for cutting process is effectively increased.
Referring to
FIG. 8
, however, face
153
of insert body
152
and wedge face
154
a
of wedge
154
are fixed by friction between the inner surface of edge groove
151
and the outer surface of insert body
152
. Thus, application of cutting force makes insert body
152
slightly shift in edge groove
151
. Then, the cutting angle of the edge with respect to face
153
slightly differs from those of the other edges. As a result, the edge having the different cutting angle is subjected to a stress which is also different from that of the other edges in magnitude. Accordingly, the edge having the different cutting angle suffers from a problem that positional accuracy and stability thereof are disadvantageously reduced.
Further, referring to
FIG. 9
, formation of edge groove
161
in such a polyhedron shape in cutter body
100
requires a slotter, wire cutter or electric discharge machine. Any of these machines has a problem in that it disadvantageously increases the number of manufacturing steps and manufacturing cost, or it is not provided with sufficient machining accuracy. Especially, cutter body
100
with a diameter exceeding
300
mm requires a large wire cutter machine and hence considerably increases the manufacturing cost.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a face milling cutter which is capable of holding an insert with high positional accuracy and which can be manufactured with low cost.
Another object of the present invention is to provide a cutter body of the face milling cutter which is capable of holding the insert with high positional accuracy and which can be manufactured with low cost.
Still another object of the present invention is to provide a clamping mechanism having a groove which can be economically formed in a simple shape to receive a holder of the insert in the cutter body.
A face milling cutter according to a first embodiment or aspect of the present invention is provided with a cutter body and a plurality of holders. The cutter body has a rotational axis and a plurality of grooves in its side surface. The holder is detachably seated in and fixed to the groove for holding an insert. The groove has a first side wall, also referred to as the one side wall, extending from the side surface toward the rotational axis, and a second side wall, also referred to as the other side wall, opposite to the one side wall and extending from the side surface toward the rotational axis. The one side wall has a first protrusion and a first recess formed closer to the rotational axis than the first protrusion. The other side wall has a second protrusion and a second recess formed closer to the rotational axis than the second protrusion. The holder is fixed to be in contact with the first and the second recesses. The first protrusion, the first recess, the second protrusion, and the second recess are also referred to herein as the one protrusion, the one recess, the other protrusion, and the other recess, respectively.
Thus, since the one and the other protrusions are positioned on the side surface side of the cutter body with respect to the holder at the side wall of the groove, even if centrifugal force acts on the holder during high speed rotation of the face milling cutter, the one and the other protrusions serve as stops that prevent the holder from flying out. As a result, the problem that the holder shifts toward, or even flies out from the groove toward, the side surface s
Fasse W. F.
Fasse W. G.
Sumitomo Electric Industries Ltd.
Tsai Henry W. H.
LandOfFree
Face milling cutter and cutter body thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Face milling cutter and cutter body thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Face milling cutter and cutter body thereof will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2552026