Note: Descriptions are shown in the official language in which they were submitted.
4~
This invention relates to a holder assembly for
an indexable insert for use in a metal cutting tool. More
particularly, a holder assembly is disclosed having a
support member connected to the cutter body, and including
a platform having interlocking key members extending
therefrom. A planar indexable insert is provided with
receiving grooves for interengaging the keys of the support
member. A screw connects the indexable insert to the
support member through a pair of registered apertures
therein. The interlocking keys and groove arrangement
functions to inhibit undesirable rotation of the insert
about the axis of the 5Crewduring use of the cutting tool.
B:~:CKGROUND OF THE INVENTION
Cutting tools in the prior art, such as end mill
cutting tools or rotatable milling tools, have been pro-
vided with indexable inserts to ;substantially increasethe
utility of the tool. More specifically, prior to the use
of indexable inserts, the replaceable blades employed had
only a single sharpened edge. To replace manufacturing
costs, an indexable insert, formed from tungsten carbide
material, was developed having a plurality of sharpened
cutting edges. In use, when a cutting edge becomes dull,
the indexable insert is merely rotated such that a fresh
sharpened edge is positioned to extend outwardly from the
cutter in an active cutting position.
To maximi~e the number of cutting edges on a
single insert, it is preferable that the insert be
symmetrical in configuration to permit indexing and
mounting of the insert in a variety of orientations. Thus,
the prior art inserts may be square, circular, triangular,
pentagonal, hexagonal or octagonal (multi-face-ted) in
configuration so as to be readialy indexed and mounted to
expose a fresh sharpened cu-tting edge.
The cutter bodies which were adapted to
receive the indexable inserts of the prior art are
generally provided with pockets adapted to receive
the inserts, which include a platform area and one
or more side walls. The indexable insert is inserted
in one of the pockets and is oriented such that one
of the planar surfaces thereof abuts the platform
surface of the pocket of the cutter body~ In addition,
the side walls of the pocket are adapted to abut the
brace one or more of the inactive sides of the insert.
By this arrangement, the side walls prevent the insert
from rotating about its central axis during the use
of the cutting tool. Preventing shifting or rotating
of the insert during use is required such that desired
axial and radial rake angle, as well as the lead
angle of the cutting edge is maintained.
As can be appreciated, the tooling or
machining of the insert pockets in a tool body is
difficult and time consuming and thus, relatively
expensive. The side walls of the pocket must be
formed with relatively high structural rigidity to
prevent the breakdown of the cutter during operation.
In addition, the number of pockets which may be
formed in a cutting tool of a given size is limited
and thus, the number of inserts which may be placed
around the circumference of the tool is correspondingly
limited.
According~y, it is an object of the subject
invention to provide an improved holder assembly for
an indexable insert which functions to restrict the
unwanted rotational movement of the insert during the
operation of the cutter.
It is another object of the subject invention
to provide a new and improved holder assembly for an
indexable insert which eliminates the need for side
walls of a receiving pocket.
It is a further object of the subject
invention to provide a holder assembly for an
indexable insert which will allow the mounting of
two or more inserts in close proximity, since the
need for the side walls of the pocket are eliminated.
By this arrangement, the number of inserts which may
be mounted on a tool of a given size is increased.
~ESCRIPTION OF THE INVENTION
In accordance with the subject invention,
there is provided a holder assembly for an indexable
insert for use in conjunction with a cutting tool.
The holder assembly includes a suppor-t member which is
connected to the cutting tool and includes a platform
portion. The support member further includes a
threaded aperture which is disposed normal to the
plane of the platform. The platform portion is
provided with a first interlocking means for
engagement with the indexable insert. In the
preferred embodiments of the subject invention, the
first interlocking means consists of at least on
key member which extends from the platform of the
support member.
The holder assembly further includes a
generally planar indexable insert having a central
aperture disposed therein which is perpendicular to
the planar surfaces of the insert. The planar insert
is mounted on the support member such that one of the
planar surfaces thereof in in ~butting relationship
with the platform portion of the support member with
the apertures therein being in register. The planar
surface of the indexable insert which in in abutting
relationship with the platform portion of the support
member inclues a second interlocking means adaped to
be interengaged with the Eirst interlocking means of
the support member. In the preferred embodiments,
the second interlocking means includes at least one
receiving groove which is adapted to be interengaged
with the key members of the support member.
The indexable insert is malntained in
abutting relationship with the platform of the support
member by a screw which extends whrough registered
apertures therein and is threadably engaged with the
aperture in the support member, and by this arrangement,
the first and second interlocking means remain
interengaged. The interengagement between the keys
and groove functions to restrict unwanted rotational
movement of the insert about is central axis during
the operation of the cutting tool. Thus, the desirable
axial and radial rakes and lead angles of the insert
may be maintained during the operation of the cutting
tool without the need for side wall locators in the
cutting tool pocket~ To insert the index the user
has merely to loosen the screw and rotate the insert.
By retightening the screw, the interlocking means
will become interengaged preventing the unwanted
rotation of the insert during use of the tool. In
addition to reducing manufacturing cost by eliminating
the need or side walls in the pockets, the subject
invention may be utilized to permit the mounting of
a plurality of indexable inserts in close proximity.
More specifically, since the requirements of side
wall structures are eliminated, a plurality of
indexable inserts may be mounted in close proximity
to increase the effectiveness of the cutting tool.
DESCRIPTION OF THE DR~WINGS
Figure 1 is an exploded view in perspective
of a first embodiment of the holder assembly of the
subject invention.
Figure 2 is a plan view of the first embodiment
of the holder assembly of the subject invention.
Figure 3 is a side elevational view of the
first embodiment of the holder assembly of the subject
invention.
Figure 4 is an exploded perspective view of
the second embodiment of the holder assembly of the
subject invention.
Figure 5 is a plan view of the second
embodiment of the holder assembly of the subject
invention.
Figure 6 is a plan view of the second
embodiment of the holder assembly of the subject
invention.
Figure 6 is a side elevational view, partially
in section, o~ the second embodiment of the holder
assembly of the subject invention.
DESCRIPTIO~ OF THE PREFERRED EMBODIMENTS
.. ..
Referring now more specifically to Figure 1-3,
a first embodiment of the holder assembly of the
subject invention is illustrated. Generally, the
holder assembly consists of a support member 20
which is adapted to be connected to a tool body 22.
The support member 20 is intended to be interengaged
with a generally square, planar indexable insert 24.
A screw 26 is provided for fastening the indexable
insert 24 to the support member 20.
Turning now more specifically to the tool
body 22, a generally planar pocket area 30 is
provided having a hole 32 therein to allow for the
connection of the support member 20 to the tool body
22. The pocket area 30 is undercut from the surface
34 of the cutting tool to provide the desired
clearance angle ~or the cutting edge of the index-
able insert 24. While the subject invention is shown
used in conjunction with a block style cutting tool,
it may readily be adaptedlfor use with a generally
circular milling cutter that rotates about a pre-
determined axis.
The support member 20 generally matches the
configuration of the insert 24, that is, square in
the subject e~odiment and includes a planar platform
area 40 and a threaded central aperture 42 disposed
normal to the plane of the platform. A cylindrical
connector 44 is provided which extends downwardly
from the side of the support member opposed to the
platform 40. The diameter of the cylindrical
connector 44 is substantially equal to the diameter
of the aperture 32 provided in the cut-ter body. By
this arrangement~ the interconnection between the
support member and the tool holder or cutter body
30 may be achieved by press fitting the cylindrical
connector 44 into aperture 32 of the tool body 22.
The connection of the support member 20 to the tool
body 22 may be achieved through various other mechanical
expedients, for example, a screw extending through
both the tool body 22 and the cylindrical connector
44 in a direction perpendicular to the longitudinal
axis of the cylindrical connector 4~. In the
alternative, the support member 20 can be formed
integrally with the tool body 22. However, it is
apparent that the mounting method used must function
to prevent the support member 20 from rotating relative
to the tool body 22.
In the first embodiment of the subject
invention, the interlocking means of the support
member 20 consists of a pluality of generally rectang-
ular keys 52, 54, 56, 58 which extend upwardly from
the planar platform 40, and are formed integrally
with the support member 20. In the illustrated
embodiment of the holder assembly, the rectangular
keys are paired, with the longitudinal axis of the
first pair of rectangular keys 52, 56 extending along
a first line, and longitudinal axis of the second
pair of rectangular keys 54, 58 extending along a
second line, which is perpendicular to the first line.
The rectangular keys are thus disposed in a generally
cross-like symmetrical configuration, surrounding the
central aperture 42 and extending to the side edges
of the support member 200 The rectangular keys of
the support member 20 are adapted to be interengaged
with receiving grooves formed in the indexable insert,
as more fully described hereinafter.
As illustrated in Figure 1, the indexable
insert 24 is provided with a generally planar, square
configuration. The overall configuration of the insert
24 is that oE a conventional positive insert wherein
the dimensions of upper square surface 60 are slightly
greater then the dimensions oF the lower square surface
62. By this arrangement, the rake faces 64 of the
insert are angled to improve the cutting ability of the
insert. A central aperture 66 is provided which is
disposed normal to the planar surfaces 60, 62 of the
insert 24. The aperture 66 is formed with a generally
frusto-conical portion 68 adjacent the upper planar
surface 60, which is adapted to receive screw 26.
In accordance with the subject invention, a
standard insert 24 is modified by forming a second
interlocking means on the lower planar surface 62
thereof. In the illustrated embodiment, the second
interlocking means includes a generally cross-shaped
receiving groove 70 having dimensions sufficient to
receive the rectangular keys 52-56. As illustrated
in Figure 2 and 3, the recei.ving groove 70 interfits
with the key members 52-56, thereby locking the insert
and preventing it from rotational movement about the
central aperture 66.
The lower surface 62 of the insert 24 is
maintained in abutting relationship wit~ the platform
40 of the support member 20 by screw 26. The latter
extends through the aperture 66 in insert 24 and is
threadably engaged within threaded aperture 42. Screw
26 consists of a flattened top portion 72 having a
hexagonal central indentation 74 to allow for the
tightening of the screw 26 by a suitable wrench or
driver. The shaft portion 76 of the screw is
generally cylindrical in configuration whi]e the head
portion 78 of the screw 26, between the shaft 76 and
the flattened top portion 72, ls generally frusto~conical
in con-Eiguration. By this arrangement, when the screw
is tightened into the threaded aperture 42, the frusto-
--8--
concial head portion 78 coacts with the frusto-conical
area 68 of hole 66 in insert 24 ln a wedge-like manner~
such that the insert is properly seated on support
member 20. More specifically, any initial misalignment
prior to the insertion of the screw will be corrected
as the screw is tightened. As illustrated in Figure
3, it is preferred that he screw 26 be tightened until
the flattened top 72 is coplanar with the upper surface
60 of the insert 24. In this embodiment of the subject
invention, cylindrical connector 44 is of sufficient
length to receive the entire shaft of the screw which
extends below the insert 24. After tightening the
screw 26, the insert 24 will be securely locked in
abutting relation with the platform 40 of the support
member 20. Further, the keys of the support member
are interfit and engaged with the receiving groove 70
of the insert 24. The secure interengagement ~unctions
to prevent the rotational shifting of the insert during
the operation of the tool.
To index the insert, screw 26 is loosened an
amount sufficient to disengage the interlocing keys
and groove to permit the rotation of the insert.
The screw 26 is then retightened to interengage the
opposed interlocking key member 52-58 and receiving
groove 70. Preferably, the key members 52-58 and the
groove 70, are symetrical in configuration to permit
the complete interengagement therebetween in each
different orientation. O~ course, when the insert
being employed is not intended to be indexed, the inter-
locking means need only be matched, rather than
symmetxical:ly Eormed.
Turning now to Figure 4-6, the second
embodiment of the holder assembly of the subject
invention in illustrated and includes a support member
120 adapted to be connected to a tool body 122. As
indexable insert 124 is provided, as well as a screw
126 having substantially the same configuration as
the screw 26 in the first embodiment of the subject
invention.
Turning more specifically to the tool body
122, a planar pocket area 130 is provided having a
configuration which aids in regulating the orientation
of the insert 124 relative to the tool body 122. A
hole 132 is provided in the pocket area 130 which
includes a large diameter portion 134 and a smaller
centrally located threaded aperture portion 136. The
threaded aperture portion 136, is adapted to receive
the end of screw 126, thereby providing an alternate
m~ans for connecting the holder assembly/ as more
fully described hereinafter.
Support member 120, which matches the insert
shape, in this embodiment is square in configuration
and includes a planar platform area 140 and a central
clearance aperture 142. ~ cylindrical connector 144
is provided on the lower surface of the support
member 120, and has a diameter substantially equal to
the larger diameter por-tion 134 of hole 132 in tool
body 122. Cylindrical connector 144 is shorter in
length than the cylindrical connector 44 of the first
embodiment of the subject invention. The support
member 120 is connected to the tool body 122 by press
~itting cylindrical connector 144 in the large diameter
portion 134 of hole 132. The clearance aperture 142
in support member 120 is thereby disposed in register
--10--
with the threaded aperture portion 136 of hole 132.
By this arrangement, the portion of the screw 126
which extends below the cylindrical connector 144
engages threaded aperture 136 provided .in the tool
body 122.
In the second embodiment of the subject
invention, support member 120 is provided wi.th an
alternative form of interlocking means, and more
specifically, is provided with four symmetrically
arranged, cylindrical key members 152, 154, 156, 158
which extend from the platform area 140. While the
cylindrical key members 152-158 are illustrated as
separate units in the exploded view of Figure 4, they
are preferably formed integrally with the support
member 120 in a manner similar to that illustrated
in the first embodiment of the subject invention.
In the alternative, four holes 151, 153, 155, 157
may be provided adjacent the corners of the generally
square platform 140 which are adapted to receive
cylindrical key members 152, 154, 156, 158. The key
m~mbers 152-158 may be press fit in holes 151-157 to
provide for a stable mounting. As illustrated in
Figure 6, the cy1indrical key members 152-158
preferably extend perpendicularly from the platform
surface a sufficient distance to provide a secure
interlock with the insert 124.
Insert 124 has a configuration similar to a
standard industry insert and includes an upper planar
surface 160 and a lower planar surface 162 of slightly
smaller dimensions, thereby defining inclined side
rake surfaces 164. A central aperture 166 is provided
havin~ a frusto-conical por-tion 168 adjacent the upper
surface 160. In accordance with the subject invention,
a second interlocking means is provided on the lower
surface of the insert 124 and consists of a symmet-
xically disposed cross-shaped receiving yroove 170.
Receiving groove 170 is adapted to interengage with
the cylindrical keys 152-158 of the support member
120. In the second embodiment of the subject
invention, and as illustrated in Figures 4 and 5,
the receiving groove 170 terminates short of the edges
or faces 164 of the insert. Preferably, key members
152-158 are disposed to interengage with the outermost
portions o:E the receiving groove 170 as most clearly
illustrated in Figure 5. By positioning the cylind-
rical key members 152-158 in the above described
manner, maximum resistance to the rotational movement
of the insert may be achieved.
Similar to the first embodiment, the lower
surface 162 of the insert 124 is maintained in abutting
relationship with the support member 120 by means of
screw 126. Screw 126 includes a flattened top surface
172 and a hexagonal indentation 174. The shaft 176
of the screw is generally cylindrical in configuration
and the head portion 178 is frusto-conical in
configuration. As in the first embodiment, the
frusto-conical head 178 coacts with the frusto-conical
opening 168 of the aperture 166, in a wedge-like manner,
during the tightening of the screw 126 to properly
seat -the insert 124. The screw 126 extends through
aper-ture 166 as well as through the clearance aperture
1~2 o the support member, and beyond cylindrical
connector 14~ and is threadably enga~ed with threaded
aperture 136. As in the :Eirst embodiment, the insert
12~ may be indexed simply by loosening the screw 126
-12-
and rotating the insert 124 to expose a new cutting
edge. Thereafter, the screw 126 is retightened to
lock the insert 124 and prevent any unwanted rotational
movement.
Accordingly, there is provided a new and
improved holder assembly for an indexable, metal
cutting tool. The holder assembly consists of a
support member which is connected to the cutting tool
and includes an upper platform surface and a central
threaded aperture disposed normal to the plane of the
platform. The platform includes a first interlocking
means which in the preferred embodiments consists of
a plurality of symmetrically arranged upstanding key
members. A generally planar indexable insert having
a central aperture therein is disposed in abutting
relationship with the platform of the support member.
The planar surface of the insert which is abutting
the platform surface of the support member includes
a second interlocking means which, the the preferred
embodiment, consists of a symmetrically arranged
receiving groove capable of interengagement with the
upstanding key members of the support member. A
screw is provided which extends through and is
threadably engaged with the apertures in the holder
assembly. The screw functions to maintain the
indexable insert in abutting relationship with the
platform of the support member, whereby the inter-
locking means remain interengaged thereby restricting
the unwanted rotational movement of the insert
during the use of the cutting tool. The above described
holder assembly functions to main-tain the insert in
the desired orientation without the necessity of
providing side wall retaining means in an insert
pocket of a tool body. By this arrangement, cuttiny
tools may be produced at a substantially reduced cost
and in addition, a plurality of inserts may be placed
in a cutting tool in close proximity, since the need
for complex pocket arrangements has been eliminated.
It is to be understood that changes may
be made in the particular embodiments of the invention
in light of the above teachings, but that they will
fall within the scope and spirit of the subject
invention as defined in the appended claims . For
example, although the invention has been described
with reference to inserts of generally square
configuration, the invention may also be embodied
in systems wherein the inserts are of triangular,
pentagonal, circular, hexagonal or octagonal
configuration, and wherein the inserts may be of a
negative or positive rake along the edges thereof.
~till further, the interlocking means in the form of
the grooves and key members may be provided on one or
both of the opposed planar surfaces of the insert
when the latter is of a negative rake configuration.
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