Note: Descriptions are shown in the official language in which they were submitted.
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FIXED DIAMETER SINGLE
PASS A3RASIVE TOOL
TECHNICAL FIELD
This invention relates to an adjustable single
pass tool including a multi-layer abrasive cutting
section and a translatable arbor to adjust and fix the
size of the cutting section.
BAC~GRO~ND ART
Prior art patents disclose expandable cutting
tools having a cutting section that adjusts as it is
rotated and axially inserted within a bore to be
: machined. For example, the U.S. Patent of Emerson
1~791~491 discloses a honing tool having a spring
biased arbor that provides tool alignment as the tool
I is rotated and moved axially in a bore through several
: 15 passes to progressively enlarge the hole on each pass.
: Likewise, the U.S. Patent of 81aylock 4r075~794 discloses
a multi-pass honing tool with a tapered arbor that
aligns the tool as it is rotated and moved axially
within a bore to be machined and which includes an
axially posi~ioned spring to bias the stones outwardly
of a body~
DISCLOSURE OF THE INVENTION
An object of ~he present invention is to pro-
vide an improved single pass cutting tool for machining
a bore upon tool rotation and single pass axial movement
through the bore to remove a predetermined amount of
stock after which the workpiece is moved to another
work station for fur-ther stock removal by a like tool if
desired and wherein the tool includes a cut-ting section
and an adjustable arbor that will adjust and fix the diameter
size of the cutting section to machine the bore to the required
single pass size and provide tool alignment during the
machining.
According to the present invention there is provlded
a single pass abrasive tool which includes a tool body with
cutting section means fixedly connectable to the body to
maintain a single pass cutting diameter for removing a
predetermined amount of stock from a workpiece bore during
a single pass axial and rotary movement of the tool through
the bore, the tool cutting section means including a plurality
of abrasive stones each having an arcuate cutting face and
each having suxfaces thereon guidingly supported both axially
and circumferentially by said body to counteract torque and
thrust loading during removal of stock from the workpiece,
each stone further including an axially inclined positioning
surface, arbor means located within said body having a large
diameter end extending from the body and including a tapered
surface thereon engageable with each of the inclined positioning
surfaces and relatively axially translatable with respect to
the positioning surfaces to adjust the diameter of the cutting
section means. Adjustment means is provided to secure the
cutting section means at an adjusted diameter whereby the
cutting section means is presettable to an initial single
pass cutting diameter and resettable to the single pass
cutting diameter to compensate for wear.
In an illustrated embodiment of the invention, the
cutting tool inlcudes a single cone shaped arbor axially
positioned with respect to a tool body by a threaded
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stud connected to the arbor and threaded through a nut
fixed to the body. A tapered surface of the cone
engages an inclined surface on each of the abrasi~e
stones to locate them to define a single pass cutting
5 diameter~ Circular springs seated in annular body
grooves and stone grooves hold the stones inwardly of
the body during single pass tool rotation and movement
through the bore. Wear compensation is produced by
adjusting the position of the arbor by cranslating it
with respect to the cutting section so as to locate it
at a desired preset cuttlng diameter for single pass
stock removal from the bore~
The too] construction disclosed is particularly
adaptable for use with abrasion cutting although other
uses are possible. In a specific e~odiment, a
unitary tool body has plural recesses to guide the
stones bo~h radially and axially thereby to define a
cutting section of fixed form. An inner tapered
surface on each of the stones provides for moun~ing of
the stones on a tapered arbor. Relative axial transla-
tional movement between the arbor and stones establishes
the size of the toolO Initial sizing of the tool for
use is thus facilitated and any wear of the abrasive
particles can be compensated for by arbor movement wi~h
respect to the stones to maintain the tool 5 i~e for
desired single pass stoc.~ removal.
The objects, fea~ures, and advantages of the
present invention are readily apparent from the follow-
ing description of the best mode for carrying out the
invention taken in connection with the accompanying
drawings~
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BRIEF DESCRIPTION OF DRAWINGS
Figure 1 is a longitudinal sectional view of a
cutting tool constructed according to the present
invention and shown mounted on a rotatable and axially
movable tool chuck;
Figure 2 is a cross-sectional view of the tool
taken along line 2-2 of Figure 1 looking in the direction
of the arrows;
Figure 3 is a cross-sectional view taken along
the line 3-3 o~ Figure 1 looking in the direction of
the arrows,
Figure 4 is a side elevational view of another
embodiment of the present invention;
Figure 5 is an end elevational view of the
embodiment of the invention in Figure 4;
Figure 6 is a fragmentary, enlarged elevational
view of a cutting tool holder in the embodiment of
Figure 4;
Figure 7 is a fragmentar~l, enlarged cross-
sectional view taken along the line 7-7 of Figure 5
looking in the direction oE the arrows;
Figure 8 is a side elevational view of a diamond
abrasion tool used in the emboaiment of Figure ~;
Figure 9 is an end elevational view of the
tool shown in Figure 8,and
Figure 10 is a perspective view of the tool of
Figure 1.
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BEST MODE ~OR C~RRYING OUT THE lN~ ON
A single pass cutting tool 10 constructed accord-
ing to the present invention is shown in Figures 1-3 of
the drawings~ The tool 10 is rnounted on a spindle
chuck 12 for rotation about an axis to provide single
pass machining of a bore upon axial tool movement
through the bore. Cutting tool 10 includes a plurality
of adjustable cutting sections 14, an adjustable arbor
16 and a threaded adjusting stud 18 at the trailing end
of the tool.
As seen best in Figure 2, the cutting tool 10
includes a unitary tool body 20 that is made from a
suitable metal such as steel. The tool body 20 has a
plurality of abrasive stones ~2 with an arcuate cutting
surface 24 of abrasive particles such as diamond or
cubic boron nitride secured thereto in a suitable
manner to define a multi-layer abrasive stone which
increases useable abrasive volume in the finishing
process O
The tool 10 is used in a single pass operation
wherein it is fed through a workpiece bore in a single
pass for removal of stock and then it is withdrawn from
the bore during a retract cycle. Such one-pass finish-
ing operations will size the bore to close size,roundness and straightness tolerances. The tool 10, as
will be discussed, is preset to a fixed diameter to
prevent manufacture of oversi2ed bores. ~s the tool 10
is fed through the workpiece bore, it is rotated to
generate the preset tool diameter through the bore.
~ sually, stock removal during each single pass is
comparatively small and limited to a maximum of a few
thousandths o~ an inch. When stock removal requirements
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exceed that obtained by single tool pass stock removal,
additional tools are arranged in-line with each single
pass station having a tool of progressively greater
diameter to produce a desired final workpiece bore
diameter without exceeding the tools capacity for
single pass stock removal. Each of the machines single
pass stations can be e~uipped with an in process gage
system of the type set-forth in United States Patent
Application Serial No. 126,922, filed March 3, l9aO
by Paul Fitzpatrick et al.
Single pass stock removal and repeatability
of the removal for a number of workpieces is in part
due to the con~iguration and fit of each of the abras-
ive stones 22.
More particularly, the tool body 20 has three,circumferentially spaced recesses 26 formed therein.
Each recess 26 receives a stone 22. Spaced, parallel,
side-walls 28,30 of each recess 26 engage and slidably
guide the side surfaces 32,34 of each stone 22. The
surfaces 32,34 firmly secure the stones 22 against
machine torque when the tool is preset to its desired
stock removal diameter. Likewise, each recess has
opposite end surfaces 36,38 which support the ends
40,42 of each stone 22 to prevent axial shift of the
stones during feed and retract of the tool 10.
Further, each stone 22 has an inboard surface
46 which is inclined with respect to a cuttin~ section
48 which is bounded at its outboard end by the arcuate
cutting surface 24.
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The surfaces 46 engage the tapered outer surace
50 of the arbor 16 to adjustably position the surfaces
24 at a pre-set cutting section diameter.
Adjustment of the arbor 16 is accomplished by
a threaded stud 52 secured to the small diameter end 54
of arbor 16 by a jam nu~ 56. The stud 52 is threadably
received by a nut sa. Nut 58 is seated in a counterbore
60 of body 20. Three equidistantly, circumf~rentially
spaced, set screws 62 in body 20 engage grooves 64 in
the nut 58 to secure it against rotation relative to
body 20. Consequently, rotation of the arbor 16 will
cause it to be translated relative to surfaces 46 to
adjust the abrasive stones to a desired preset diameter
for single pass removal of stock.
The outside diameter of the large diameter end
of arbor 16 has serrations 66 formed therein at a
desired precalibrated circumferential spacing to
reflect a predetermined amount of tool cutting section
diameter change for each increment of rotation of arbor
16. A spring plunger 68 seated in an end bore 69 of
body 20 to ride into and out of the serrations 66. This
produces an audible indication and retention of the
adjusted position of arbor 16 and allows calibration of
diameter change to compensa~e for wear of stones
22.
Each of the abrasive stones 22 is hçld inboard
of the recess side walls 28,30 and end surfaces 36,38
by a pair of circular springs 70,72 that are seated in
arcuate grooves 74,76 formed at axially spaced points
in the body 20. Each of the abrasive stones also
i.ncludes spaced spring grooves 78,80 aligned with body
grooves 74,76 to seat the springs 70,72 substantially
inboard of the cutting surfaces 24 thereby to assure
that the tool 10 can be adjusted for wear without
exposing the springs to the cutting process.
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Further, the tool body 20 includes an extension
80 with a small diameter end 82 that is received by a
chuck and an intermediate diameter 84 which slidably
supports a gage plug of the type set forth in abo~e-
identified United States Serial No. 126,922.
In operation, the arbor 16 is rotated to cause nut
56 and stud 52 to translate the arbor 16 axially into
or out of body 20. Movement of the arbor 16 into the
body 20 will increase the single pass stoc~ removal
diameter of the cutting sections 14. Movement of the
arbor 16 outwardly of the body 20 will reduce the
diameter of the cutting sections 14. This adjustment
feature is readily adaptable to automatic tool adjustment
systems wherein arbor rotation and consequent translation
is produced by directing a rotatable cornpensation shaft
86 through a bore 88 in the extension 80.
Another embodiment of the present invention
is set forth in Figures 4-9. A presettable, fixed
diameter, single pass tool 90 is shown. It includes a
unitary body 92 having a plurality of tool recesses 94
located at circumferentially spaced locations. Each
recess has spaced side walls 96,98 which support a pair
of!inserts 100. More particularly, a side 102 of an
abrasive insert 100 is supported by wall 96. An
opposite side 104 of another insert 100 is supported by
wall 98. Opposite sides 102,104 of the pair of inserts
1 no engages the sides 106,108 of an insert clamp ll0
Each insert clamp 110 is wedge shaped as shown
in ~igures 5 and is held in place by a pair of screws
112,114 to positively secure the abrasive inserts 100
in place on the body 92 to establish a cutting section
of fixed diameter as defined by cutting surfaces 116 on
the inserts lOOo
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Adjustment of the fixed diameter is accomplished
by relative translational movement between an inclined
sur~ace 118 at the bottom of each recess 94 and an
inclined ramp 120 on the base of each insert 100. To
increase tool diameter, each clamp 110 is released by
backing screws 112,114 from a shoulder 122 inboard
of each clamp 110. The inserts 100 are released
and are free to be translated axially to the right as
viewed in Figure 5. Such movement will cause the
inserts 100 to shift outwardly of the recesses 94.
Increase in tool diameter is produced by reverse
movement of the inserts 100. Following adjustment the
insert clamps 110 are wedged against the inserts to fix
the desired diameter once the screws 112,114 are
threaded into the body sufficiently to tightly engage
shoulder 122.
The aforedescribed embodiments of Figures 1-3 and
Figures 4-9 disclose fixed diameter cutting tools
especially configured to produce single pass finishing
operations for improved hole size, roundness and
straightness.
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