Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates to chuck jaw assemblies.
In particular this invention relates to a chuck jaw assembly
having a gripping member releasably mounted thereon.
PRIOR ART
Chuck jaws are conventionally made from ha dened
steel or from unhardened steel.
The chuck jaws which are made from hardened steel
have the advantage of having superior wear resistance to
those which are made from unhardened steel and they have a
superior gripping ability in that they are more easily
embedded into a workpiece. Hardened chuck jaws such as
those commonly made from steel are expensive and are
difficult to machine when worn.
Chuck jaws which are made from unhardened steel
can be easily machined; however they wear very rapidly with
the result that they require considerable maintenance.
Furthermore, repeated replacement of chuck jaws increases
the down time in the operation of production machinery.
An additional problem which is encountered in the
use of conventional chuck jaws is in the gripping of the
workpiece with sufficient clamping force to permit high load
machining of the workpiece. Frequently the ability of the
chuck jaws to rigidly clamp the workpiece determines the
rate at which machining of the workpiece may be effected
rather than the power output capacity of the machine.
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I have found that the above difficulties can be
overcome by forming a chuck jaw assembly in which a gripping
member is releasably mounted in the body of the chuck jaw
and wherein the gripping member is made from a wear
resistant material such as hardened steel. The grip~ing
member is releasably mounted on the body of the chuck jaw
assembly.
With this combination it is possible to make the
body o the chuck jaw from an unhardened metal while making
the gripping members from a hardened metal. I am now able
to obtain the advantages to be derived from the use of
hardened chuck jaws or unhardened chuck jaws without the
disadvantages normally associated therewith.
According to one aspect of the present invention,
a chuck jaw assembly comprises; a body adapted to be mounted
in a chuck so as to be movable between a work engaging
position and a work release position, said body having a
clamping face arranged to be disposed in a face to face
relationship wi~h a workpiece in use, a first gripping
member releasably mounted on said body such that a gripping
portion thereof projects beyond said clamping face of said
body to be engageable with a workpiece in use, said gripping
member being formed from a wear resistant material.
According to a further aspect of the present
invention a chuck jaw assembly comprising; a body having
slide portions adapted to be mounted in a chuck so as to
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be movable between a work engaging position and a work
release position, and at least one jaw segment mounted on
said slide portion, each jaw segment having a clamping face
extending in an arcuate path, a pair of seats formed in each
jaw segment at circumferentially spaced intervals along its
clamping face, each seat having a bottom wall and a pair of
side walls, said side walls extending at right angles to one
another with the plane which bisects the angle formed
between the side walls extending radially of said arcuate
path, a pair of gripping members for each jaw segment, each
gripping member having four side faces arranged in the
square configuration and forming clamping edges at each
corner formed between adjacent side faces, said gripping
members being releasably seated within each of said seats of
said jaw segment whereby any one of said clamping edges may
be positioned to project from said clamping face, said
gripping members being formed from a wear resistant material
such as.
The invention will be more clearly understood as a
reference to the following detailed specification read in
conjunction with the drawings wherein:
Figure la is a front view of a chuck jaw
constructed in accordance with an embodiment of the present
invention,
Figure 2a is a sectional view taken along the line
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2-2 in Figure la,
Figure 3a is a sectional side view through a
portion of a jaw segment constructed in accordance with a
further embodiment to the present invention,
Figure 4a is a sectional side view of a portion of
a jaw segment constructed in accordance with another
embodiment of the inven-tion,
Figure 5a is an end view of a jaw segment suitable
for use as an internal clampiny jaw,
Figure 6a is a sectional side view of a jaw
segment taken on the line 6-6 of Figure Sa,
Figure 7a is a side view similar to Figure 6a
showlny dn a'ternative jaw segment construction,
Figure lb is a front view of a chuck jaw assembly
in which the jaw segment is pivotally mounted,
Figure 2b is a sectional view along the line 9-9
of Figure lb,
Figures 3b and 4b are sectional side views of jaw
segments facilitating alternative embodiments of the present
invention,
Figure Sb is an end view of the chuck jaw
assembly of Figure lb,
Figure lc is a front view of a chuck jaw assembly
constructed in accordance with yet another embodiment of
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the present invention,
Figure 2c is a partially sectioned side view of
the chuck jaw assembly of Figure lc,
Figure 3c is a sectional side view of a chuck jaw
segment constructed in accordance with yet another
embodiment of the present invention,
Figure 4c is a sectional side view of a chuck jaw
assembly constructed in accordance with still further
embodiments of the present invention, and
With reference to the drawings like numerals apply
to like parts throughout the specification.
With reference to Figure 1 of the drawings the
chuck jaw assembly comprises a body 10, a removable jaw
supporting segment 1, and a pair of gripping members 5. The
segment 1 is secured to the base 2 by a plurality of cap
screws 4. A back stop 7 is mounted on the segment 1. A
centering pin 3 is mounted on the base 1 and projects into a
notch 14 formed in the segment 1. The gripping members 5
are releasably secured to the segment 1 by means of mounting
screws 6. A pair of mounting passages 12 are formed in the
base 2 for use in releasably securing the chuck jaw assembly
2 by a conventional chuck jaw support wherein the chuck jaw
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assembly is mounted for movement toward and away from a
workpiece.
A pair of seats 16 are formed in each jaw segment
at circumferentially spaced intervals along the clamping
face 18 of the segment 1. Each seat has a bottom wall 20
and a pair of side walls 22. The side walls 22 extend at
right angles to one another and line 24 which bisects the
angle formed between the side walls 22 extends radially of
the arcuate path and the clamping face 18.
The gripping members 5 each have four side faces
26 arranged in a square configuration forming clamping edges
28 which project radially inwardly from the clamping face
18. The corners 28 are chamfered from above and below to
form a sharp point which serves to bite into the workpiece.
The base portion is preferably made from steel
which is readily machinable whereas the gripping members are
preferably made from a hardened tool steel or a carbide
material which has good wear-resisting characteristics.
Figure 3 of the drawings illustrates a further
embodiment in which the corners 28 are machined to a
sawtooth configuration to provide increased gripping
capacity. Figure 4 illustrates a further embodiment in
which gripping members are mounted at the inner and outer
faces of the segment.
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In the embodiments illustrated in Figures 1
through 4 the chuck jaw assembly is suitable for use as one
of a number of jaw assemblies used to clamp the ex'ernal
periphery of the workpiece.
Figures 5, 6, and 7 illustrate further embodiments
of the invention in which the clamping members 5 are mounted
radially inwardly from the clamping face 18. This form of
segment is suitable for use in association with a chuck jaw
to provide for the clamping of the internal periphery of a
workpiece. Figures 6 and 7 illustrate ~he manner in which
gripping members 5 are seated in the segment 8.
In the embodiments illustrated in Figures 8
through 11, the segments 1 have a stem portion 30 mounted in
a passage 32 and retained by a retaining plate 34 and
mounting screw 36. The segment 1 is rotatable about the
axis 38 so as to be self-aligning.
The embodiments illustrated in Figures 13 through
16 differ from those of Figures 8 through 11 in that two
segments 1 are mounted on the base 2. Both of the segments
1 are rotatable about their axis 38 so as to be
self-aligning.
From the foregoing it will be apparent that the
present invention provides a simple and inexpensive chuck
jaw assembly in which the hardened workpiece gripping
members are small in size in proportion to the main body of
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the chuck jaw assembly and are releasably mounted thereon so
that after they are worn they may be removed and replaced by
new gripping members. Furthermore, the gripping members are
shaped to provide an improved gripping ability. These and -
other advantages of the present invention will be apparent
to those skilled in the art.
