Note: Descriptions are shown in the official language in which they were submitted.
~3C~
DISPOSABLE
GRINDINC7 APPARATUS HAVING AN INTEGRAL
MOUNTING HUB
Field of the Invention
This invention relates generally to abrasive
finishing articles and more particularly to abrasive
grinding apparatus having a mounting hub permane~tly
lU affixed thereto with the combination adapted for
attachment to an appropriate portable power tool. More
specifically the invention has application to disposable
depressed center grinding wheels.
Ba kqround of the Invention
The use of rotatably driven grinding devices
i9 widespread and familiar in our industrial society.
One of the more serious problems encountered in the use
of such devices resldes in the provislon of effective
means for preventing undesired or accidental
disassociation of the grinding device such as a wheel
from the shaft, spindle or other rotatable drive means
on which it is mounted. This problem is particularly
acute when the connection between the grinding apparatus
and it5 driving shaft or spindle is intentionally
detachable to facilitate quick removal and replacement
of the grinding apparatus. Into this category fall a
host of devices, for example, portable powered grinders
~k
~3~36~
wherein grinding wheels employed are intentionally
detachable from the power driven shaft so that they may
be readily replaced. To properly mount the grinding
wheel upon the shaft provision must be made to provide
sufficient clamping force and also to secure the wheel
rotationally.
One means of securing the grinding wheel to
the drive shaft has been to provide an appropriate
lU backing flange with a central opening which is aligned
with an opening provided in the abrasive grinding wheel.
A bolt or nut member (depending upon the con~iguration
of the drive shaft, that is, whether it is externally or
internally threaded) is inserted from the face side of
the grinding wheel and is then tightened in place. In
this manner a plurality of loose parts are configured in
a completed assembly ready for use. As the grinding
wheel is utilized the appropriate clamping force is
provided to securely affix the grinding wheel to the
~U drive shaft. Such an assembly, however, typically
requires appropriate tools such as wrenches or the like
to remove the grinding wheel from the drive shaft. Such
a device is shown in U.S. Patent Nos. 3,596,415;
1,998,919; 566,883; 507,223; 1,162,g~0; 791,1S9; 4~9,14
and 3,210,8~2.
Subsequently it became desirable to affix the
mounting hub permanently to the grinding wheel so that
the entire unit may be quickly and easily attached and
detached from the drive shaft and discarded when the
~U grinding wheel has been worn down. In these types of
devices it is customary to utilize an adhesive such as
an epox-y resin or the like between the backing flange
and the back surface of the grinding wheel to retain
integrity between the mounting hub and the grinding
wheel to secure the wheel rotationally.
~30~
Even though the adhesive tended to work quite
well in most applications, it was discovered that in
some ins~ances the adhesive would brea~ loose and the
grinding wheel woula rotate relative to the mounting
hub. Such was particularly the case since the hub was a
one-piece member which was internally threaded and held
in place upon the grinding wheel by swaging an extension
thereof into place, thus providing a fixed clampin~
force holding the grinding wheel. No additional
clamping force was exerted during further rotation of
the wheel during use as was the case with the
traditional nut which was secured from the face as above
described. As a result various keyways and
corresponding key structures were developed between the
wheel and the mounting hub and used in conjunction with
,the adhesive to preclude rotational movement between the
mounting hub and the grinding wheel. Examples of such
devices are shown ln U.S. Patent Nos. 3,136,100;
~0 4,015,371; 2,278,301; 3,081,584; 3,500,592; 3,800,483;
A,240,230 and 4,541,205.
Additional prior art patents known to
applicant are U.S. Patent Nos. 3,041,797; 3,879,1~8;
1,~24,~42: 3,912,411; 3,8~9,178; 3,960,S16; 4,026,0~4;
25 4,054,425; 4,088,729; 4,601,661; 791,~91; ~2,932;
2,56~,782; 3,136,100, 3,210,892 and 3,621,621.
The devices utillzed in the prior art for
providing the disposable grinding wheel asse~bly
lncluding the permanent affixed mounting hub generally
3U provide the service intended. There are certain
inherent disadvantages found with regard to the various
devices. Such disadvantages are that in manufacturing
the utilization of an adhesive adds additional materials
and labor to the cost of manufacturing. In certain of
the devices, parts must be keyed together and properly
aligned in order to function appropriately. In addition
~hereto, throush the utilization of die-cast mounti~
hubs which include as an integral par~ the backing
flange there is no additional clamping force exerted
upon the grinding wheel as it is being rotated by the
power tool. Furthermore, such die-cast mounting hubs
are relatively bulky, take up space and add substantial
weight and additional cost to the completed product.
ummarY of the Invention
A grinding apparatus having a drive member
non-removably affixed thereto for mounting on a
rotatable spindle of a power tool. The drive member
includes a backins flange on one side of the apparatus
and a retaining nut positioned on the opposite side of
the apparatus from the backing flange. The nut extends
through an opening from the face toward the back of the
apparatus and has a radial flange at one end thereof
seated against the face of the apparatus and protrusion
means extending from the other end thereof for non-
removably securing the retaining nut and the backingflange together on the apparatus without the use of
adhesives.
Loosely retained upon the power tool spindle
is a base member which engages the outer surface of the
backing flange to apply pres6ure to the ~lange during
operation of the apparatus.
Alternatively, a pressure cap member may be
affixed to the protrusion means. The pressure cap
defines a central opening through which the power tool
spindle extends to engage the nut.
More particularly, the securing means and the
base member on the one hand or the pressure cap on the
other are adapted to cause the nut and backing flange to
place the apparatus in compression between them when the
apparatus is operatively secured upon the spindle of the
power tool.
~3~
Brief De cr~ption of the Draw_~g~
FIGURE 1 is a cross sectional view of a
disposable grinding wheel assembly constructed in
accordance with the principles of the present invention
and mounted in operable position on the spindle of a
power tool;
FIGURE 2 i5 an exploded view of the structure
as illustrated in FIGURE 1;
1~ FIGVRE 3 is a cross sectional view of a
backing flange constructed in accordance with the
present invention;
FIGURE 4 is a cross section view of a
retaining nut constructed in accordance with the
principles of the present invention;
FIGURE 5 is a cross secti~nal view of the
retaining nut of FIGURE 5 after beihg upset;
FIGURE 6 is an alternative construction of a
spindle base assembly constructed in accordance with the
~0 present invention for use on small grinding wheels;
FIGURE ~ i5 a cross sectional view of an
alternative embodiment of the grinding wheel assembly
constructed in accordance with the principles of the
present inventlon including a pressure cap and mounted
2~ in operable position on the spindle of a power tool;
FIGURE 8 is a cross sectional view showing
construction of the pressure cap constructed in
accordance with the present invention;
FIGURE 9 i9 a cross sectional view of another
~0 embodiment of a disposable grinding wheel assembly
constructed in accordance with the principles of the
present invention;
FIGURE 10 is a cross sectional view of a
backing flange constructed in accordance with the
present invention;
FIGURE 11 is a cross section view of a
retaining nut constructed in accordance with the
principles of the present invention;
FI~UR~ 12 is a cross sectional view of the
retaining nut of FIGURE 5 after being upset;
FIGURE 13 is an alternative construction of a
spindle base assembly constructed in accordance with the
present invention for use on small grinding wheels;
1~
Detailed Description
By reference now more specifically to FIGURES
1 through 5, there is illustrated a preferred embodiment
of a disposable grinding apparatus assembly constructed
in accordance with the princlples of the present
invention. Although the present invention has utility
with respect to any disposable power driven grinding
apparatus, the description herein is given with respect
to a depressed center grinding wheel. As is shown in
the drawings, a depressed center grinding wheel 10 has a
disposable drive member assembly 12 permanently aff xed
thereto 80 that the grinding wheel ~ay be attacned to
the spindle 14 of an appropriate power tool 16.
According to the principles of the present invention, a
disposable mounting hub or drive member ls constructed
in such a manner that when the grinding wheel i5 placed
in operation upon the spindle 14 the grinding wheel 10
is placed in compression and the more force which is
applied to the grinding wheel during utillzation
thereof, the greater the operational compression
becomes. As a result of placing the grinding wheel in
such compression the grinding wheel is maintained upon
the spindle and cannot fly off and at the same time,
through the compression or clamping force as applied,
the drive wheel 10 cannot rotate relative to the driving
member or hub 12. However, as a result of the
construction of the driving member, the spent grinding
wheel may be easily removed from ~he spindle for
disposal without the utilization of hand tools or the
like.
As is clearly shown, the grinding wheel 10
includes a back surface 18 and a front surface 20. The
central portion of the grinding wheel is depressed as
viewed from the front thereof and as i5 shown at 22,
with a correspondinq central raised portion 24 on the
back thereof. A centrally located aperture 26 is
provided in the depressed center portion of the grinding
wheel 10. The purpose of the depressed center of the
grinding wheel 10 is to insure that the driving member
or spindle does not protrude beyond the face portion 20
of the wheel 10 and thus interfere with a workpiece
during the time the grinding wheei 10 is being utilized.
A backing flange 28 is provided and is adapted
to be snugly received on the back surface 18 of the
grinding wheel lO about the raised portion 24. The
flange 28 has a diameter which is less than the diameter
of the wheel 10. The backing flange 28 defines a second
central aperture 30 therethrough which is aligned with
the aperture 26 in the grindinq wheel 10. A pair of
.5 reinforcing ribs 32 and 34 are formed in the backing
flange 28 concentrically with the opening 30. The
backing flange 28 is preferably stamped from sheet metal
but of course could be constructed from other materials
such as hard molded plastic or die cast metal should
3U such be desired.
As is shown more specifically in FIGURE 3, the
backing flange 28 includes an inner surface 36 and an
outer surface 38. The inner surface 36 is disposed
opposed the back surface 18 of the abrasive finishing
wheel 10. The inner surface 36 includes a pair of lands
40 and 42. The land 40 always is formed about the outer
~L3~
peripheral portion of the backing flange 28. The land
42 is displaced inwardly toward the opening 30 and away
from the land 40. The land 40 engages the back surface
18 of the abrasive finishing wheel away from the
depressed center while the land 42 may engage the back
surface of the abrasive finishing wheel 10 opposed the
depressed center 22 thereof depending upon variations in
wheel dimensions and manufacturing tolerances in the
wheel and flanges.
As can be seen, particularly in FIGURE 3, the
ribs 32 and 34 formed in the outer surface 38 of the
backing flange 22 are continuous. The continuous rib 32
is disposed between the lands 40 and 42 and over the
transitional area between the depressed center and the
remainder of the grinding wheel lO while the continuous
rib 34 is disposed intermediate the opening 30 and the
land 42.
A retainer nut 44 includes a body portion 46
which is hollow and has a radially outwardly extending
flange 48 at a first end 50 thereof. At the opposite or
second end 52 of the body and slightly displaced
therefrom there is provided a recess such as a
continuous groove 54 which is formed at the time of
assembly after the body 46 is inserted through the
openings in the wheel 10 and backing flange 28. The
internal surface of the body 46 has threads 56 ~ormed
therealong for attachment to the threaded spindle 14 of
the power tool. The nut 44 is inserted through the
aperture 26 in the grinding wheel and the aperture 30 in
the flange 28 from the front 20 toward the rear 18 of
the grind.ing wheel 10. The end 52 of the nut 44 extends
through the opening 30 in the flange 28 for a distance
not exceeding the top of the rib 34.
Once the nut 44 has been inserted through the
openings in the wheel 10 and the flange 28, the end 52
thereof is upset such as by a staking operation to
provide the continuous groove 54 as shown specifically
in FIGURE 5. The upsetting operation causes a
protrusion 56 to extend outwardly from the body 46 in
such a manner as to engage the flange 28 about the outer
surface 38 thereof adjacent the opening 30 therethrough
and is the only means used for securing the flange 28
and the nut 44 on the wheel 10. The protrusion 56 is
illustrated as being continuous as is the groove 54,
although it should be understood that it may be
intermittent should such be desired. It should become
apparent to those skilled in the art that the flange 28
and the nut 44 are mechanically secured together on the
wheel 10 between the flange 48 and the protrusion 56
without the use of adhesives.
The nut 44 is preferably constructed from an
aluminum extrusion which is then machined to provide the
flange 38 and the threads 46. Alternatively the nut may
be formed from aluminum or steel bar stock, or a metal
die casting.
To provide proper operation of the throw-away
grinding wheel as described in one embodiment, there is
provided a base assembly 60 which includes a disc 62
having a first surface 64 at least part of which ls
adapted for engaging the outer surface 3~ of the flange
28. The disc 62 is held in place on the spindle 14 by a
retaining member 66 which, as shown in FIGVRE 1 in the
preferred embodiment, may be a nylon annulus which is
threadable onto the threaded spindle 14. The nylon
annulus 66 will then loosely retain the disc 62 upon the
spindle 14 at all times whether or not a grinding wheel
is maintained in place. The first surface 64 of the
disc 62 defines continuous ridges 68 and 70 which engage
the ribs 34 and 32, respectively, of the flange 28 as
can be seen. As i5 F,hown the ridges are displaced
~3~8~
downwardly and the disc defines a chamber or pocket into
which the nut 44 may be partially retracted during use.
The contact between the ribs and ridges is essentially a
line contact. As a result of ~he line contact the wneel
10 ma~ usually be relatively easily removed from the
power tool 16. However, because of the tremendous
amount of force which may have been exerted by the disc
62 during the grinding operation the spent wheel may
sometimes be difficult to remove.
Positioned between the opposite surface 65 of
the disc 62 and the shoulder 69 on the power tool 16 is
a plastic washer 67 constructed preferably of a self-
lubricating plastic. The washer 67 serves two
functions. The first function is to accommodate power
tools 16 of varying dimensional configurations. That
is, the spindle 14 may vary in lengt;- requirin~ spacers
to assure the end of the spindle does not protrude
beyond the end of the nut 44 by any su~stantial amount.
The second function is to assist in removal of the wneel
10 from the power tool 16 after the wheel 10 is spent.
Since tremendous forces are generated during a grindin~
operation, metal-to-metal surfaces, particularly of
similar t~pes, tend to bind or gall thereby
necessitating the application of relatively large ~orces
to remove the spent wheel. The self lubr:icating
dissimilar surfaces between the washer 6'l and shoulder
69 and surface 65 provide an almost immediate release
upon the application of m$nimal pressure to wheel 10.
Thereafter the line contact above referred to allows
easy separation of the wheel from the base assembly 60.
The force necessary to cause the grinding
wheel 10 to be placed in compression is generated upon
attachment of the spindle 14 to the threads 56 in the
nut 44. By reference to FIGURE 1 it will be noted that
when the grinding wheel is threaded upon the spindle 14
.~
~3~
the ridges 68 and 70 engage in a line fashion the ribs
34 and 30 on the flange. The flange is forced in a
downward d rection by such engagement. At the same time
the interengagement between the threads 14 and 56 of the
spindle and nut, respectively, urge the nut upward
toward the flange 28 to cause the grinding wheel to be
placed in compression. An examination of the drawings,
particularly FIGURE 1, will disclose that when t~e
grinding wheel is in operation forces are transmitted
downwardly from the power tool 16, the washer 6~, the
disc 62 and the land 40 of the flange 28. At the same
time, forces are being applied upwardly through the
flange 48 on the nut 44. These forces are generated
through the threaded engagement between tne spindle 14
and the interior 56 of the nùt 44 through application of
torque to the rotating wheel when it is placed into
engagement with a workpiece. Those skilled in the art
will recognize that as the grinding wheel lO is used by
being placed against a workpiece additional torque is
applied causing the grinding wheel to be further
tightened onto the spindle 14. That is, as the grinding
wheel moves during contact with a workpiece, the
friction between the nut and the grinding wheel center
causes the nut to rotate in a further tightening
direction. Such rotation of the nut further urges the
nut towarcl the flange which in turn applies a further
force to the flange. The more the grindirg wheel is
tightened the greater the operational compression force
becomes and the more securely the grinding wheel lO is
clamped between the backing flange 28 and the flange 48
on the nut 44. As a result of this strong clamping or
compression the grinding wheel lO is precluded from
movement relative to the hub or drivinq member 12 and at
the same time is precluded from disengaging from the
spindle 14. It should also be noted that the inner
12
surface 64 of the disc 62 provides a space or chamber 71
above the top 52 of the nut 44. This chamber 71
provides room for the nut to move upwardly durinq
operation in a manner unrestricted by the power tool or
base assembly.
FIGURE 6 illustrates an al~ernati~e structure
similar to that shown in FIGURE 1 but specifically
designed for use with smaller grinding wheels, for
example, those having a diameter of five inches or less.
The only difference is that the disc in the base
assembly is of smaller diameter and designed to engage
only the ~irst rib adjacent the opening through the
backing flange. As is shown, the disc 80 defines a
peripheral surface 82 which engages the top surface of
the continuous rib 34 on the backing flange 28. It has
been found that the smaller grinding wheels do not
require the larger backing flange for satis~actory
operation although it should be understood that the
smaller grinding wheels operate satisfactorily with the
larger backing flanges.
Alternatively, as illustrated in ~I~U~ES 7 and
8, to provide proper operational compressive forces of
the throwaway grinding wheel as above~descriDed, a
pressure cap 90 is snapped into locking eng~gement with
the hub assembly lZ. Under these circumstances the base
assembly 60 as above described will be dispensed witn.
The pressure cap 90 includes a first rear surface 92 for
engaging the surface 69 on the power tool spindle wnen
the grinding wheel is in an operable position on the
power tool 16. A second or front surface 96 on the
pressure cap 90 contacts the top of the continuous rib
34. The pressure cap 9o is retained in position on the
hub assembly 12 by a gripping rib 98 which extends
radially inwardly from a downwardly depending skirt 84
on the front surface 96 of the body 84 of the pressure
~3~
cap 90. The gripping rib 98 snaps over the protrusion
56 and engages the lip 5~ on the enc 52 of the retainer
nut 44. At the same time the surface 74 on the
continuous reinforcing rib 34 of the backing flange 28
applies a radially inwardly directed force to secure the
gripping rib 98 in place in the space between the lip 57
and the periphery of the backing flange surrounding the
opening 30. Preferably the pressure cap 90 is
constructed of molded plastic such as polypropylene,
polyamide, acetal or the like. The gripping rib 98 may
be continuous or intermittent as desired as illustrated
by the dashed lines 99. An important feature is that
the pressure cap may be easily snapped into locking
position as shown in FIGURE 1 by the distributor or user
before use if desired or, alternatively, at the time of
assembly in the factory. Such capability saves space in
shipment in that the assembled wheel without the
pressure cap may be packed in containers with pressure
caps placed in interstices between wheels or wheels and
the container. Thus a greater number of wheels may be
packaged, on top of each other, in the same container.
It will also be recognized that the pressure
cap 90, once installed, remains on the g~inding wheel
and is di~sposed of along with the spent wheel.
The force necessary to cause the grinding
wheel 10 to be placed in compression is generated upon
attachment of the spindle 14 to the threads 56 in the
nut 44. By reference to FIGURE 7 it will be noted that
when the grinding wheel is threaded upon the spindle 14
the surface 92 engages the surface 69. Force i5 thus
transmitted through the pressure cap 90 to the backing
flange 28 through the contact between the surface 96 and
the reinforcing rib 34 causing the backing flange to be
forced in a downward direction. At the same time the
interengagement between the threads 14 and 56 of the
14
spindle and nut, respectively, urge the nut upward
toward the flange 28 to cause the grinding wheel to be
placed in compression. Those skilled in the art will
recognize that as the grinding wheel 10 is used by being
placed against a workpiece additional torque is applied
causing the grinding wheel to be further ti~htened onto
the spindle 14 as was the case with the base assembly
60.
By reference now more specifically to FIGU~ES
9-13, there is illustrated another embodiment of a
disposable grinding wheel-drive member assembly
constructed in accordance with the principles of the
present invention. As is therein shown a depressed
center grinding wheel 10 has a disposable drive member
assembly 12 permanently affixed thereto so that the
grinding wheel may be attached to the spindle 14 of an
appropriate power tool shown in phantom at 16.
As is clearly shown, the grinding wheel 10
includes a back surface 18 and a front surface 20. As
is clearly shown the central portion of the grinding
wheel is depressed as viewed from the frort thereof and
as is shown at 22, with a corresponding central raised
portion 24 on the back thereo~. A centrally located
aperture 26 is provided in the depressed center portion
of the grinding wheel 10.
A backing flange 128 is provided and is
adapted to be snugly received on the back surface 18 of
the grinding wheel 10 about the raised portion 24. The
flange 128 has a diameter which is less than the
diameter of the wheel 10. The backing plate or flange
128 defines a second central aperture 130 therethrough
which is aligned with the aperture 26 in the grinding
wheel 10. A reinforcing rib 132 is formed in the
backing flange 128 concentrically with the opening 130.
The backing plate or flange 128 is preferably stamped
13~
from sheet metal but of course could be constructed A~rom
other materials such as hard molded plastic should such
be desired.
A retainer nut 134 includes a body portion 136
which is hollow and has a radially outwardly extendin~
flange 138. At the opposite end 142 of the body and
slightly displaced therefrom there is provided a recess
such as a continuous groove 144. The internal surface
of the body 136 has threads 146 formed therealong for
attachment to the threaded spindle 14 of the power tool.
The nut 134 is inserted through the aperture 26 in the
grinding wheel and the aperture 130 in the flange 128
from the front 20 toward the rear 18 of the grinding
wheel 10.
A hollow cup-shaped member 150 is slipped over
the upper portion of the retaining nut which extends
beyond the flange ~8 and is non-removably secured to the
nut by depressing a portion thereof into the groove 144.
As is shown, the hollow cup (spindle cup) has a side
wall 152 with a radially outwardly extending flange 154
disposed at the end 156 thereof. The opposite end 15
of the sicle wall 152 is turned inwardly and defines a
third aperture 160 therethrough. The inwardly turned
portion of the side wall 152 al60 functions a~s a
locating area for the spindle 14 of the power tool '6
thus making it relatively easy for a user to locate the
grinding wheel upon the power tool 16. The side wall
152 of the cap 150 may be affixed to the groove 144 of
the nut by a simple staking operation to provide
indentations as shown at 164 and 166 of FI~UR~ 1. It
will be obvious to those skilled in the art that the
indentations 164 and 166 may be one or more in number
and may be independent or alternatively a compete
continuous upset of the side wall 152 may be
accomplished if desired. It will further be recognized
16
that the continuous groove 144 may be formed in a
discontinuous manner, that is, a plurality of recesses
should such be desired. In any event the cup 150 is
affixed to the nut 134 in a non-removable fashion but in
such a manner that the cup and nut may be urged
relatively toward each ot~er to place the grinding wheel
10 in compression.
The force necessary to cause the grinding
wheel 10 to be placed in compression is generated upon
attachment of the spindle 14 to the threads 146 in the
nut 134. By reference to FIGURE 1 it will be noted that
when the grinding wheel is threaded upon the spindle 14
the surface 69 (which may be an appropriate washer,
spacer or a portlon of the spindle) engages in a line
fashion, the upper surface 170 of the domed or curved
portion 162 of the side wall 152. Thus, the cup is
forced in a downward direction by such engagement. At
the same time the interengagement between the threads 14
and 146 of the spindle and nut, respectively, urge the
nut toward the cup. Since the surface 172 of the flange
154 on the cup 150 engages the surfaces 174 on the
backing flange 128, a force is applied through the
backing flange and the back surface 18 of the grinding
wheel 10 to cause the yrinding wheel to be placed in
compression as above described with respect to the base
assembly 60 and the pressure cap 90.
If desired, the flange 128 and the cup 150 may
be formed as an integral unit as is shown in FIGURE 12.
If such is desired, the composite nut-flange may be
stamped from a single piece of sheet metal to provide
the desired depression area 180 to accommodate the
raised portion 24 of the depressed center wheel. From
the central section of the body 182 there would be
extended the side walls 184 of the cup with the inwardly
turned end 186 to provide the dome structure 188 as
~L3~
above described. As desired, the reinforcing -ing l9O
may also be included.
It will be recognized by those skilled in the
art that the grinding wheel assemblies as illustrated in
the drawings and as above described requires no adhesive
for construction and may be simply and easily assembled,
is relatively light in weight as compared to the prior
art devices utilizing the cast hubs and provides a
secure attachment of the grinding wheel to the power
tool and through the utilization of the increased
compression precludes relative rotation of the grinding
wheel with regard to the driving member. It has also
been discovered that the utilization of the device as
lS above described and as constructed in the preferred
embodiment is extremely smooth in op~ration with no
vibration. The reason for such extremely smooth
operation is that all of the parts are perfectly aligned
one with the other with the abutting surfaces parallel
when in compression and only the wheel lO can cause any
vibration and then only if it is not properly ~alanced
during the construction thereof.
Through the structures as illustrated and
described, all currently known sizes of standard
diameter depressed center grinding wheels, namely four
inch, four and one half lnch, ~ive inch, seven inch and
nine inch may be accommodated. At the present time,
through the utilization of the die-cast integral hub-
flange structure, only seven and nine inch grinding
wheels utilize the throw away hub while the four, four
and one half and five inch wheel utilize the
conventional two-piece mountinq set traditional in the
prior art and as above described.
There has thus been disclosed a disposable
grinding wheel-driving member assembly which securely
holds the grinding wheel during operation, which is
~3~5~
18
light in weight, vibration-free, and less expensive than
prior art throw-away grinding wheels while meeting all
safety standards currently known and in existence.
