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Патент USA US3054242

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Sept 18, 1952
D. R. LOWTHER ETAL
3,054,232
ROUND DISC WITH NON-CIRCULAR BACK-UP PAD
Filed Sept. 20, 1960
INVENTORS
DWIGHT R. LOWTH ER
By HOWARD R.WRIGHT
él/iqz 221%“
ATTORNEY
United States Patent 0 "
3,054,232
Patented Sept. 18, 1962
1
2
power-driven back-up pad having one major planar axis
3,054,232
longer than the other and having an arcuate edge at each
ROUND DISC WITH NON-CIRCULAR
BACK-UP PAD
end of said major planar axis.
Referring now to the drawing, the abrasive disc 10
Dwight R. Lowther, Waterford, and Howard R. Wright,
Troy, N.Y., assignors to Norton Company, Troy, N.Y.,
consists of the paper and/or cloth backing member 11
with a coating of abrasive grains 12 bonded thereto by
a resin or glue adhesive. The representation of the disc
Filed Sept. 20, 1960, Ser. No. 57,226
10 has been cut-away as at 13 to show the ‘back-up pad
2 Claims. (Cl. 51-195)
14 formed of hard rubber or the like. The abrasive disc
The present invention relates in general to an improved 10 10 is secured .to the pad 14 by any suitable holding means
abrasive cutting tool and more speci?caly to a method
as illustrated at 15. Pad 14 is formed with arcuate edges
and means for improving the cutting e?iciency of a
16 and 16’ conforming generally to that portion of the
coated abrasive disc.
periphery of abrasive disc 10 immediately adjacent there
Heretof-ore the coated abrasive disc, which may be
to, and a pair of straight connecting sides 17 and 17’.
de?ned as a disc, the backing of which comprises paper 15 The portions of the pad covered by the disc have been
or other non-woven cellulose material and/ or cloth,
shown in dotted lines to permit better visualization or
which disc is provided with a coating of abrasive grains
the combination.
and is relatively stiff and rigid in its own plane and has
In operation, it has been found that this combination
a corporation of Massachusetts
the capacity of resisting torsional and ‘buckling strains
of disc and back—up pad produceslsurprising results in
and of ?exing under lateral pressure and which is con 20 the amount of abrading that can be done with any given
structed to be held from the center and used with yield
abrasive disc. The intermittent support afforded by the
ingly supported pads, has been developed as an extreme
pad of di?erent con?guration than the disc permits a
ly important industrial and household tool. Generally
beating action of the disc against the workpiece, result
such discs have been used with back-up pads formed
ing in ‘greatly improved cut. A limited and controlled
from rubber or the like wherein the back-up pads con 25 degree of automatic slippage between the disc and the
formed in general to the shape of the disc. In other
back-up pad is desirable in order to insure that the entire
words, where a circular disc was used, the back-up pad
surface of the disc is used in the abrading process.
was also circular in shape although it might have a
The following examples are illustrative only and are
somewhat shorter radius than the radius of the disc and
not intended as limitations upon the scope of the present
where the disc was other than circular, e.g. hexagonal, the 30 invention other than as may appear from the appended
pad also was hexagonal.
claims.
A recent development which is described and claimed
EXAMPLE 1
in the copending application of Leland H. Vorce, Serial
No. 9,345, ?led February 17, 1960, and now abandoned,
A test Was run with two identical circular vulcanized
is that of an abrasive disc having a con?guration equiva 35 ?ber coated abrasive discs—grit 36-~one mounted on a
lent to that of a circular disc from which has been out
conventional back-up pad (circular) and the other mount
two parallel chords-equi-spaced from the center of the
disc, giving a structure with a pair of arcuate cutting
ed on a pad such as described in the aforesaid Vorce
application. The two discs were tested on the same
edges connected by two straight edges. This disc which
power-driven spindle under a dead weight of 9 pounds
has substanital use in certain industrial applications is 40
and at an angle of 10° to the workpiece—in each instance
mounted for use on a similarly shaped back-up pad as
a 4" x ‘11/8 ” x 13" piece of No. 1020 hot rolled steel
has been conventional practice.
plate. Readings were taken at 1 or 2 minute intervals
It has now been found that the cutting e?iciency of the
and the test continued until the rate of cut (or stock re
ordinary round or polygonal disc can be greatly im
proved by mounting such disc ‘on the back-up pad de 45 moval) reduced below 5 grams in any 2-minute period.
Table A below is the conventional disc plus the con
scribed in connection with the abrasive disc of the afore
ventional circular back-up pad. The total cut ‘for this
said Vorce application.
disc was arbitrarily designated as 100%.
Accordingly, it is an object of the present invention
to provide an improved coated abrasive tool.
Table B below is the conventional disc plus the non
circular pad described above.
It is a further object of the invention to provide a
method and means for increasing the cutting e?iciency
of conventional coated abrasive discs.
Additional objects, if not speci?cally set forth herein,
will be readily apparent to one skilled in the art from the
following detailed description of the invention:
In the drawings:
Table A
55
Time
FIGURE 1 is a perspective view of a coated abrasive
disc mounted in accordance with the present invention
and partially cut-away to show the back-up pad.
Generally, the present invention comprises mounting 60
positioning of a conventional circular abrasive disc on a
Shed
(m1n.)
Conventional disc plus
conventional pad.
an abrasive disc for rotation on a back-up pad of a con
?guration other than that of the abrasive disc.
More speci?cally, the present invention includes the
Out
interval (qms.) (qms.)
Total ____________ .-
1.0
1. 0
2.0
2.0
18
10
13
2
0.3
0. 0
0.5
0.0
6. 0
43
0.8
Temp. of Total
work- percent;
piece, °F
cut
230
220
300
220
........ __
100
3,054,232
4
3
Table D
'Table B
Cut
Time
Time
interval
Total
Shed
out
percent
piece, “F.
cut
5
Conventional disc plus
non-circular pad.
Conventional disc plus
non-circular pad.
iODQC -lomcaeg .opNsaoHcrz-lw
10
15
tH-IH
..g,
Total ............ -_
Total
Shed
(min)
percent
(time) (qms.)
interval
(m1n.)
Gut
(qms) (qms)
g \1
529 20
._.
Total ____________ __
W
.
o
a
p
g
s
w
c
OQcCD
636
Again the improvement in cut of the disc was marked
when backed up by the pad having a diilerent con?gura
1At this point the pad was indexed approximately 90°.
tion than that of the disc-—-—in this case better than 6
25 times the total cut of the conventional combination.
It should be noted that in Examples I and II above,
su?icient slippage between the disc and the non-circular
The test showed an improvement in cut of better than
5 times over the conventional disc and pad.
pad was ‘allowed to permit the pad during the abrading
operation to have ‘an accumulative slip of about 180°
30 relative to its position as the start of the test.
EXAMPLE 2
Obviously many modi?cations and variations may take
place without departing from the spirit and scope of
the invention described herein and therefore only such
A second set of identical discs were tested under the
same conditions as in Example 1 with the following re
sults:
limitations should be imposed as are contained in the
35
appended claims.
We claim:
1. An improved abrading tool which comprises: a
circular coated abrasive disc and a mounting pad there
Table C
Time
for, said mounting pad having a major planar axis sub‘
stantially equal in length to the diameter of said disc
Cut
Shed
Temp. of Total
interval (qms.) (qms.) work- percent
(min.)
piece, "F
cut
Conventional disc plus
1.0
19
0.3
300
conventional pad.
1. O
2.0
2.0
10
11
1
0. 2
0.3
0.0
230
280
300
6. 0
41
0. 8
Total ____________ _-
________ _.
and a minor planar axis at right angles to and shorter
than said major planar axis, said disc being ai?xed to
said pad so as to be rotated therewith against a work
piece.
2. A tool as in claim 1 wherein said pad has an arcuate
45
edge at each end of said major planar axis.
100
References Cited in the ?le of this patent
UNITED STATES PATENTS
1,966,299
2,696,700
Kent et a1 ____________ ._.. July 10, 1934
Tocci _______________ -.. Dec. 14, 1954
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