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Патент USA US2136022

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Nov. a, 1938.‘
w, D, Rossow
Filed Feb. 10, 1937
2 Sheets-Sheet l
Walter D.Ro$xs0w.
M WW 3%
. Nov. 8, 1938.
' w. D. ROSSOW
Filed ‘Feb. 10, 1937
2 Sheets-SheetZ
Wu Z 201D. Ross-oar.
$020 M7? 2r fwzz‘
Patented Nov. _ 8, 1938
Walter D. Bossow, Ti?in, Ohio, assignor to. The
Sterling Grinding Wheel Company, Ti?in,
Ohio, a corporation of Ohio
Application February 10, 1937, Serial No. 125,031
4 Claims. (01. spa-1s)
The present invention relates to abrasive ar
ticles and more particularly to a method of mak
by suitable cores molded therein during manu
ing abrasive articles having sections of weakly
bonded material and/or apertures therein.
facture, and subsequently removed. The abra
sive article A shown is of the type adapted for
An object of the present invention is the pro
vision of a novel method of making an abrasive
therethrough, all of which apertures were made '
use with a commercially known surface grinder, 5 _
having a vertical grinding spindle, and has a I
article having a section of weakly bonded ma
plurality of nuts I!‘ embedded therein through
terial and/or an aperture therein, wherein a core
the medium of which it can be secured to the
or the like of weakly bonded material is employed
10 in forming the section of weakly bonded mate
grinder spindle.
As shown in Fig, 1, the depth of the clearance 10
rial and/or the aperture.
grooves 10 is about 85% to 90% of the height
Another object of the present invention is ‘‘the. of the article. This necessarily weakens the disk
provision of a novel method of making an abra
to some extent and while the disk shown in Fig.
sive article having an aperture therein, which
‘ 15 comprises molding weakly bonded material into
the article, which weakly bonded material is sub
sequently removed to form the article.
Further objects and advantages of the inven
tion will be apparent to those skilled in the art
20 to which the invention relates from the follow-v
ing description of the preferred embodiments
1 is satisfactory for most purposes, at times a
stronger disk may be desired. Fig. 6 shows-a l5
modi?ed construction in which the same arrange
ment of clearance grooves shown in Fig. 1 is
maintained in the working face of the disk with—
out weakening the disk to the same extent. As
shown in Fig. 6 the clearance grooves l5, which 20
panying drawings forming apart of this speci?ca
open into the upper or working surface of the
abrasive disk B, are only one-half as deep as the
clearance grooves 10 shown in the disk A, and
' tion, in which similar reference characters desig
are supplemented by rectangular apertures I6
thereof, described with reference to the accom
25 na e corresponding parts throughout the several
vie s, and in which:
g. 1 is a perspective view of one form of abra
si e article embodying the present invention;
Fig. 2 is a perspective view of a mold showing
80 one stage in the production of the abrasive ar
ticle, shown in Fig. 1, by the methodof the pres
ent invention;
Fig. 3 is a section on the line 3-3 of Fig. 2;
Figs. 4 and 5 are sections similar to Fig. 2,
86 but showing further advanced stages in the
- Fig. 6 is a perspective view similar to Fig. 1
showing an abrasive article of modi?ed construc
. tion embodying the present invention, and
Fig. '7 is a perspective view similar to Fig. 2 but
showing a stage in the production of the abra
sive article shown in Fig. 6 by the method of
the present invention.
According to the provisions of the present in
vention abrasive articles having desired sections
of weakly bonded .material and/or apertures
therein are formed by molding therein suitable
cores or the like, of weak bonded material which
cores orlthe like are either‘allowed to remain in
'l the article to form sections of weakly bonded
material or are removed to form apertures.
Fig. 1 shows an abrasive article,vin the form of
which appear as clearance grooves in the work- 25
ing face of the disk as the disk wears away in
use. The apertures l6, which become clearance
grooves as‘the wheel wears away, are spaced in
termediate the grooves l5 and are similar in size
and shape. The bottoms of the grooves I 5 are 30
preferably either in the same plane with the top
of the apertures l6 or extend slightly below the
same so that the apertures I6 come to the work, '
ing surface of the disk at or before the time
the clearance grooves l5 disappear.
In both of the preferred embodiments shown
in Figs. 1 and 6 the weakly bonded core material
has been removed leaving the grooves or apertures
l0, l5, and IE, but it is to be understood that the
bonded core material may be allowed to 40
in the disk if desired. This does not in
with the operation of the disk as the
bonded material wears away faster than
the article itself. If the weakly bonded material
is of the proper character the disk can be ma- 45
terially strengthened by'allowing the core to re
main in position, as will be hereinafter more
speci?cally pointed out.
In the art of making abrasive articles of the
type referred to, as commonly practiced, the 50
“mix", which comprises suitable abrasive mate
rial such as silicon carbide, aluminum oxide, etc.,
an. abrasive disk ‘A. _ provided with clearance
thoroughly mixed with a sufiicient quantity of ‘
‘grooves l0 opening into ‘the working surface
a suitable binder such as resin, rubber etc., is
placed in a suitable mold, subjected to high pres- 55
‘ thereof and K a central aperture ll
sure, and subsequently cured, thus producing a
ably shaped cores or masses or weakly bonded
with the mix. The extent to which the material
is compressed depends upon the density desired in
the ?nished article, but assuming that ‘it is com
pressed to two-thirds of its former height the
cores will likewise be compressed to substantially
two-thirds of their former size, see Fig. 5. The
compressed articles are subsequently cured in the
abrasive ‘or other material in the mold along with
the “mix”. After the article has been cured the
usual manner and if the loose material of the
cores is not thereafter already gone, it is re
cores are either allowed to remain therein to
form the sections of weakly bonded material or
are removed leaving the desired apertures. . The
sive article having a section of weakly bonded
strong bonded abrasive article. In general the
method of the present invention follows the
aforesaid procedure except that a desired section
of weakly bonded material and/or apertures in
the ?nished product are formed by placing suit
cores or masses of weakly bonded material do not
interfere with the pressing step or operation since
15 being weakly bonded, they compress along with
the “mix” and the result is a finished article of
equal density. In the ?nished article the last
mentioned characteristic, that is, equal density,
is highly important and cannot be obtained by
20 the use of rigid cores or the like.
Suitable removable cores may be made from
abrasive material such as silicon carbide or alu
minum oxide weakly bonded with linseed oil or
some similar material which will set by the time
25 the cores are used, and which bond will be broken
during the pressing operation leaving practically
no strength. It has been found that by the time
the disk is ?nished, cores of this character, will be
partly, if not entirely, gone and any particles
30 thereof remaining can be readily removed. If the
core is to be left in the article thereby forming a
section of weakly bonded material therein and the
strength of the article thereby increased, the
Had it been desired to produce an abra
material therein rather than having opened
apertures therein, the core material would pref
erably have been weakly‘bonded with a limited
quantity of a reversible resin as previously pointed 15
Substantially the same steps are employed in
making the article shown in Fig. 6. First the nuts
I2 and the cylindrical core l9 are placed in the
mold D and enough “mix” l8 added to just cover 20
the nuts l2 when compressed. The cores 23 which
are similar to the cores 20 except that they are
only one-half as high, are then placed on this
material as a base, and after being suitably
braced, enough “mix” is run into the mold to ?ll 25
the same to the tops of the cores 23. Thereafter
the cores 24, similar in construction to the cores
23, are placed on this material as a base, see
Fig. 6, and enough “mix” run into the mold to just
?ll the same to the tops of the cores l9 and 24, 30
or slightly cover the same. The material is then
compressed in the usual manner and the result
ant article cured, after which the loose material
of the cores may be removed to leave well de?ned
grooves. During the compression step'the cores
weakly bonded material or core preferably com
35 prises a reversible resin, that is one which never
cures at all or only upon prolonged heating. Cores ' 23 and 24 crush down and are compressed in the
made of abrasive material, such as silicon carbide same manner as the cores 20 referred to before.
Abrasive articles of various sizes and shapes,
or aluminum oxide weakly bonded with a’ small
having various kinds of apertures therein can be
quantity of shellac or a glycerol phthalic anhy
readily produced by the present method. It will 40
40 dride resin, are very suitable for this purpose.
Referring to Fig. 2, the reference character C ' also be apparent that abrasive disks with clear
ance grooves of any desired shape or con?gura
designates a mold in which the “mix” l8 and the
tion, and of any depth, can also be formed. While
cores l 9 and 20 are placed and subsequently com
the disks shown are adapted to be secured to the
pressed. The size and shape of the mold will de
spindle of the grinder with which they are adapt 45
pend upon the article being made and in the pres
ed to be used, through the medium of nuts I! em
ent instance consists of a member having a cylin
drical cavity therein since it is desired to make a bedded in the underside thereof, it is to be under
stood that the disk may be formed on a_ steel
disk-like’ article. After the core I9 has been
properly centered in the cavity of the mold and backing plate, or with bolts or studs embedded
therein and projecting from the rear side, or any
50 the nuts I2 correctly located, enough “mix" is
placed in the mold, which when compressed will other conventional means may be employed in at-.
taching the same to the machine with which it is
just cover the nuts. The cores 20 which as shown,
to be used.
are narrow slabs or strips, are then placed or
From the foregoing description it will be ap
stood on this base and braced in some suitable
parent that the objects heretofore enumerated 55
side thereof. As shown the cores 20 are tangent have been accomplished and that a new and im
to the cylindrical core l9 and project radially with
respect to the ?nished article. In the present in
stance the cores 20 are made of silicon carbide or
60 aluminum oxide boded with linseed oil since it is
desired to remove the same from the cured article,
thus producing an abrasive disk having opened
clearance grooves l0, see Fig. 1.
After the cores have been properly located and
65 braced the rest of the “mix”'is run into the mold
in the usual manner. The amount of loose “mix"
employed is preferably such that after it is leveled
it just-comes to the top of the cores, of slightly
covers them, see Fig. 4. The material is then
70 pressed in the usual manner and the cores, being
weakly bonded, ‘do not buckle but merely crush
proved method of making abrasive articles, has
been provided. As already‘ stated the invention is
not limited to the particular articles shown or the
speci?c steps employed in the preferred ‘manner
of practicing the method herein described, all of
which may be varied within the scope of this in
yention. The term ‘mix” as used throughout this
speci?cation including-the appended claims, in
eludes any suitable mixture of abrasive material
and binder employed in making strong bonded
abrasive articles.
Having vthus described my invention, I claim:
1. The method of making an abrasive article
having-an aperture therein which comprises plac
ing a suitable weakly bonded core in a mold along
down with or without‘an increase in width and
with the mix_from which the article is made, com
are compressed with the rest of the material. ‘ pressingthe'material thereby crushing the core,
Preferably the density of the cores or weakly and subsequently curing the compressed material.
76 bonded material is such that it’compresses along
. 2. The method of making an abrasive article
' 2,188,022
having an aperture therein which comprises form
ing the aperture by means of a weakly bonded
the core and the mix in volume, curing the com
pressed material, and removing the core material.
4. The method of making a solid disk-type abra
core placed in the material from which the article
is made, compressing both the material and core sive article having a clearance groove in the work
thereby crushing the latter, and subsequently - ing surface thereof which comprises placing a 5
weakly bonded'core in the mold along with the
.curing the compressed material.
3. The method 01' making an abrasive article
having an aperture therein which comprises plac
10 ing a suitable weakly bondedcrushable core in a
mold along with the mix from which the'article
is made, compressing the material to reduce both
material from which the article is to be made,
subjecting the material to pressure to compact the
same and crush the core, curing the compressed
material, and removing the core material.
WALTER '1). Rossow.
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