Grinding wheel assembly

A grinding wheel assembly having a throw-away type hub construction in which the insert member imbedded in the molded abrasive disk hub portion is provided with a plurality of circumferentially spaced grooves in the juncture between the cylindrical section and annular flange section thereof. The die cast metallic shaft engaging member is provided with mating tongues or projections shaped to engage axially within the grooves when the extremity of the cylindrical portion of the die cast member is swaged into engagement with the adjacent face of the hub portion when in assembled relation therewith.

This invention relates to the connection of rotatably driven members with 
driving shafts and more particularly to an improved grinding wheel 
assembly for connection with a driving shaft end. 
The use of rotatably driven grinding or abrasive wheels is widespread and 
well known. Also well known are the problems incident to the connection of 
such wheels to the shaft which is utilized to drive them. It is now 
accepted practice in many instances to provide such wheels with an 
inexpensive integrally assembled hub construction configured to facilitate 
the attachment of the grinding wheel to the shaft end. In many instances, 
such grinding wheels with integral "throw-away" hub constructions are 
considered to be more efficient than the utilization of grinding wheels of 
the type requiring the utilization therewith of re-usable arbor parts for 
effecting the connection of the grinding wheel with the shaft. Basically, 
the throw-away assemblies are considered sufficiently advantageous from 
the standpoint that the time required to effectively replace a worn-out 
grinding wheel with a new grinding wheel is considerably reduced. Thus, 
grinding wheel assemblies with throw-away hub constructions are greatly 
preferred in situations where grinding wheels must be relatively 
frequently replaced. 
Since grinding wheels assembled with throw-away hub constructions provide 
for a relatively quick and effective threaded connection with the shaft 
(but see U.S. Pat. No. 3,210,892), connection failure between the shaft 
and abrasive wheel has occurred in this type of assembly between the 
member of the assembly which connects to the shaft and the abrasive disk 
itself. In order to minimize such failures in operation, it has been 
proposed to provide an adhesive interconnection between the shaft engaging 
member and the abrasive wheel, see, for example, U.S. Pat. No. 3,081,584 
and 3,136,100. While the utilization of adhesives has served to increase 
the strength of the connection between the abrasive disk and the shaft 
connecting member as compared with prior art connections of the type 
without such adhesive, the utilization of adhesives adds expense to the 
assembly both in terms of added material and assembly costs. Moreover, 
such adhesives have not proven to be entirely effective. 
Accordingly, it is an object of the present invention to provide a grinding 
wheel assembly having a throw-away type hub construction having improved 
means for preventing failure of the connection between the shaft engaging 
member and the abrasive disk of the assembly which overcomes the 
disadvantages noted above. In accordance with the principles of the 
present invention, this objective is obtained by providing a plurality of 
annularly spaced grooves in the sheet metal insert member of the assembly 
in the juncture between the cylindrical section and annular flange section 
thereof. With such grooves provided in the sheet metal insert member which 
is molded with the abrasive disk so as to be imbedded in the hub portion 
thereof, the cast metallic member of the assembly is provided with mating 
projections or tongues. When these members are assembled the shaft 
engaging member is effectively keyed to the abrasive disk by intermating 
tongue and grooves formed in metallic members of the assembly. 
Consequently, the chances of failure by a relative turning movement 
between the shaft engaging member and the abrasive wheel are reduced to a 
minimum without the necessity of providing additional material in the form 
of an adhesive or additional operative steps in the assembly of the 
component parts of the grinding wheel assembly. 
Another object of the present invention is the provision of a grinding 
wheel assembly of the type described which is simple in construction, 
effective in operation and economical to manufacture. 
These and other objects of the present invention will become more apparent 
during the course of the following detailed description and appended 
claims. 
The invention may best be understood with reference to the accompanying 
drawings wherein an illustrative embodiment is shown.

Referring now more particularly to the drawings, there is shown in FIG. 1 
thereof a grinding wheel assembly, generally indicated at 10, embodying 
the principles of the present invention. As shown in FIG. 1 and in the 
exploded view illustrated in FIG. 4, the grinding wheel assembly 10 
consists essentially of three component parts: a sheet metal insert 
member, generally indicated at 12; an abrasive wheel member, generally 
indicated at 14, formed by molding with the sheet metal member 12 imbedded 
therein; and a die cast metallic shaft engaging member, generally 
indicated at 16. 
The sheet metal insert member 12 is preferably stamped from thin gauge 
metal so that it provides a thin walled structure which includes a 
cylindrical section 18 and an annular flange section 20 extending radially 
outwardly from one end of the cylindrical section 18. Formed in the 
juncture between the cylindrical section 18 and the annular flange section 
20 is groove means in the form of a plurality of circumferentially spaced 
grooves 22. As best shown in FIGS. 3 and 4, each groove 22 is essentially 
triangular in configuration and opens in an axial direction opposed to the 
direction of extent of the cylindrical section 18 from the annular section 
20. 
The abrasive wheel member 14 is formed of a molded material having suitable 
abrasive particles imbedded therein so as to present at least one 
operative abrasive surface, indicated at 24. As shown, the abrasive 
surface constitutes one annular face of a disk-like member having a 
disk-shaped hub portion 26 which is offset axially with respect to the 
annular portion providing the operative face 24, the direction of axial 
offset being such that the disk-shaped hub portion 26 is recessed with 
respect to the operative face 24. 
It will be understood that the abrasive wheel member 14 is formed of 
moldable material compositions known in the prior art. Examples are set 
forth in the patents previously referred to, the disclosures of which are 
hereby incorporated by reference into the present specification to 
exemplify the composition of the material embodied in the abrasive wheel 
member. 
In order to insure a solid fixed engagement of the insert member 12 in 
imbedded relation within the hub portion 26 of the abrasive wheel member 
14, there is formed in the annular flange section 20 of the insert member 
12 a series of annularly spaced openings 28 formed by deflecting portions 
30 of the annular section axially in a direction toward the end of the 
cylindrical section 18 opposite to the end to which the annular flange is 
connected. It will be noted that the projections 30 extend into the molded 
material of the hub portion 26 as best shown in FIG. 2 to provide for a 
resistance to the turning of the insert member 12 with respect to the hub 
portion 26. It will also be noted that the material of the hub portion 
contacts the exterior surface of the cylindrical section 18 and the 
surface of the annular flange section 20 facing in the direction of axial 
extent of the cylindrical section 18 from the flange section 20, leaving 
the opposite surfaces of both sections exposed. 
The shaft engaging member 16 is a cast metallic member preferably die cast 
of a zinc aluminum alloy as disclosed in the aforesaid patents. The cast 
metallic member 16 includes a cylindrical hub connecting portion 32 having 
an exterior diameter slightly less than the interior diameter of the 
cylindrical section 18 of the sheet metal member 12, an annular hub face 
engaging flange portion 34 extending outwardly from one end of the 
cylindrical portion 32 and a central shaft connecting portion 36 extending 
axially from the annular flange portion 34. The shaft connecting portion 
36 is provided with interior surfaces shaped to engage cooperating 
surfaces provided in the shaft end (not shown) and, as shown, such 
surfaces are preferably in the form of conventional threads 38. The 
exterior of the shaft connecting portion 36 is formed with surfaces shaped 
to be engaged by a wrench as, for example, flat surfaces 40 forming a 
square exterior configuration. The flange portion 34 is shaped to conform 
with the recessed configuration of the hub portion 26. It is important to 
note that there is formed in the juncture between the cylindrical portion 
32 and the flange portion 34 of the member 16 tongue means adapted to mate 
with the groove means of the insert member 12, such tongue means being in 
the form of a corresponding plurality of circumferentially spaced tongues 
or projecting elements 42 of a triangular shape, generally corresponding 
to the triangular shape of the grooves. 
The cast metallic member 16 is adapted to be fixed to the wheel member 14 
with the sheet metal member 12 imbedded therein in an assembled position 
in which the cast metallic member and wheel member with the sheet metal 
member imbedded therein are aligned axially and moved axially together so 
that the cylindrical portion 32 of the cast metallic member 16 extends 
through the exposed interior surface of the cylindrical section 18 of the 
insert member 12 outwardly of the face of the hub portion 26 corresponding 
with the operative face 24. It will be noted that the flange portion 34 of 
the cast metallic member is disposed in adjacent relationship with the hub 
portion 26. In accordance with conventional practice, a paper washer 
containing safety data and other identifying information may be provided 
between the annular flange portion and the wheel member, such paper washer 
being omitted from the drawings as not essential to the assembly. It is 
important to note that in the assembled position the projecting tongues 42 
of the die cast metallic member 16 matingly engage within the 
corresponding plurality of grooves 22 formed in the insert member 12. 
Finally, it will be noted that the cast metallic member 16 is retained in 
its assembled position with respect to the wheel member 24 and imbedded 
insert member 12 by swaging the exterior of the cylindrical portion 32 
which extends outwardly of the aforesaid hub portion face so as to deform 
the same annularly outwardly into a bead or rim configuration 44 which 
extends axially inwardly into engaged relation to the adjacent hub portion 
face. 
It can thus be seen that there has been provided a grinding wheel assembly 
10 which includes three basic components capable of economic individual 
fabrication and assembly. It will be noted that the provision of the 
grooves in the juncture between the cylindrical section 18 and the annular 
flange section 20 of the insert member 12 not only provides for a 
cooperating relationship with the tongues or projecting elements 42 of the 
die cast member 16 but serves to provide for a more rigid and permanent 
connection of the insert member 12 in imbedded relation within the hub 
portion 26. The effectiveness of the connection of the insert member 
within the hub portion is further enhanced by the provision of the 
integral projections 30 and openings 28 formed thereby within which the 
moldable material extends during the molding operation. With the insert 
effectively mounted within the grinding wheel member so that there can be 
no relative rotational movement of either of these members with respect to 
the other, an effective assembly which will transmit all of the rotational 
movement of the shaft to the grinding wheel with minimum failure is 
accomplished by the engagement of the tongues 42 within the grooves 22 and 
the securement therein by the bead 44 created by virtue of swaging action 
of the extremity of the cylindrical portion 32 of the member 16. 
It thus will be seen that the objects of this invention have been fully and 
effectively accomplished. It will be realized, however, that the foregoing 
preferred specific embodiment has been shown and described for the purpose 
of illustrating the functional and structural principles of this invention 
and is subject to change without departure from such principles. 
Therefore, this invention includes all modifications encompassed within 
the spirit and scope of the following claims.