US2806331A - Grinding wheels - Google Patents

Description

Sept. 17, 1957 E. JQHOYE GRINDING WHEELS- Filed Aug. 24, 1956 VENTOR Hoye 1 ATTORNEY GRINDING WHEELS Emmett John I-Ioye, Wauwatosa, Wis. Application August 24, 1956, Serial No. 606,052 6 Claims. (Cl. 51-168) This invention relates to molded grinding wheels and particularly to those of the so-called cup type.

Grinding wheels of this character are commonly composed of suitably bonded abrasive materials molded into the desired form, and commonly comprising a rather thick walled structure including a circular base wall with an integral annular peripheral wall projecting therefrom. The peripheral wall commonly slopes outwardly and away from the base wall and terminates in a substantially flat annular surface constituting the principal grinding face of the wheel. The wheel is ordinarily supported and rotatively driven by an appropriate shaft or spindle disposed axially thereof, one end of the shaft being fixed to and within the circular base wall at its center.

Such wheels are subject to fracture or disintegration under the centrifugal forces developed at the high rotative speeds ordinarily employed, a condition tending not only to shorten the normal life of the wheel but also, and more importantly, exposing the operator to the continuous threat of serious injury by flying fragments thrown from the wheel. In some instances this condition is aggravated by the torque reaction between the supporting drive shaft and the center of the wheel.

Various attempts heretofore made to overcome this condition have not proven entirely satisfactory. They have consisted largely in the provision of inserts of various forms embedded in the base of the wheel with a view to reinforcing the same. But, as heretofore designed and applied, such inserts tend to localize and concentrate the destructive internal stresses within the wheel rather than to sustain or alleviate the same.

One object of the present invention is to materially increase the holding power of a molded grinding wheel against fracture or disintegration under the centrifugal forces developed during normal use.

Another object is to provide a molded grinding wheel reinforced to effectively sustain the internal stresses commonly developed therein during normal use.

Another object is to provide a molded grinding wheel having means for rendering the same shatter-proof in the event of fracture from any cause.

Another object is to provide improved means for driving a molded grinding wheel by the application of driving torque to the periphery thereof.

Other objects and advantages will appear, expressed or implied, from the following description of a molded grinding wheel embodying the present invention.

In the accompanying drawing:

Figure 1 is a view in perspective of a reinforcing element constructed in accordance with the present invention for use with molded grinding wheels particularly of the type shown in Fig. 2.

Fig. 2 is a perspective view, partly broken away, of a molded grinding wheel equipped with a reinforcing element such as exemplified in Fig. l.

The grinding wheel selected for illustration is of a well known molded type composed of suitable granular mg Patent abrasive material bonded together by an appropriate bonding material. It comprises a rather thick walled cup-like structure including a circular base wall 10 and an outwardly sloping annular peripheral wall 11 integral with and projecting from the base wall. The peripheral wall 11 terminates in a substantially flat annular face 12 constituting the principal grinding face of the wheel.

In this instance the grinding wheel is shown seated in the reinforcing element 13 of Fig. 1. The wheel is preferably molded into the element 13 so as to provide a secure integral union therewith.

The reinforcing element shown comprises a shallow cup-like stamping, preferably of sheet steel of high tensile strength, having a substantially flat disc-like bottom 14 spanning the base wall 10 of the wheel and a continuous peripheral flange 15 tightly encircling the latter. The flange 15 serves as a band-like binder capable of holding the Wheel against fracture or disintegration under the centrifugal forces developed in normal use. The flange is preferably of a depth substantially corresponding to the thickness of the base wall 10 of the wheel, so as to clear the peripheral wall 11 and thus to avoid interference with the grinding function of the latter throughout its entire depth.

The flange 15 of the reinforcing element also functions as a peripheral driver for the wheel and for this purpose is securely anchored thereto. A plurality of inwardly directed tangs 16 struck up from the flange 15 and embedded in the base wall 10 of the wheel adequately serve this purpose.

The reinforcing element shown also functions as a carrier for the wheel, and for this purpose is equipped with suitable means for mounting the same on a coaxially disposed supporting drive shaft 17. In this instance the means shown for this purpose comprises a hub 13 seated in a central opening provided in the bottom 14 of the reinforcing element and rigidly fixed thereto preferably by welding, as indicated at 19. The hub 18 is hollow and internally threaded to receive the threaded end of the shaft 17. The hub is preferably embedded in the wheel, and the outer periphery of the hub is preferably knurled or otherwise fashioned, as at 20, for interlocking engagement with the base wall 10 of the wheel to provide additional anchorage between the reinforcing element and the wheel.

It will thus be noted that the reinforcing element is secured to the wheel at its center by the hub 18, and at its periphery by the flange 15 and tangs 16, and that these parts cooperate to render the wheel shatter-proof in the event of fracture from any cause. That is to say, should fracture of the wheel occur, the hub 18, flange 15 and tangs 16 cooperate to retain, at least temporarily, any loose fragment or fragments of substantial size resulting from such fracture, so as to avoid exposing the operator to the peril of hazardous flying parts.

It will be further noted that, since the hub 18 and flange 15 are rigidly united through the bottom disc 14 of the reinforcing element, the driving torque received from the drive shaft 17 is transmitted therethrough to the periphery of the wheel where it is applied to best mechanical advantage in driving the wheel, and so that any objectional torque reaction between the drive shaft and wheel center is avoided.

Various changes may be made in the invention hereinabove specifically described without departing from or sacrificing the advantages of the invention as defined in the appended claims.

I claim:

1. The combination with a molded grinding wheel having relatively thick walls including a circular base wall and an annular peripheral wall integral therewith and projecting therefrom, of reinforcing means for said wheel comprising a shallow, cup-like structure of sheet metal forming a seat for said wheel and :into which said wheel is molded to provide a secure integral union therebetween, said structure .including a disc shaped bottom anda bent-up peripheral flange tightly encircling the outer periphery of said .wheel to .a depth corresponding to .the thickness of said base Wall to sustain said .wheel against fracture under the centrifugal forces developed therein in normal use.

2. The combination .of claim 1, wherein said cup-like structure also includes means embedded in said wheel at the periphery thereof to provide peripheral application of driving torque.

.3. Thecombination of claim 1, wherein tangs projectinginwardly from said flange are embedded in said wheel at .the .outer periphery thereof.

4. Thecombination of claim 1, wherein said cup-like structure also includes means projecting into and embedded in said wheel at .the outer periphery thereof and also .at the center thereof, whereby to retain fragments of the wheel in the event of fracture thereof.

5. The combination of claim 1, wherein said cup-like structure also includes a centrally disposed shaft-receiving hub rigidly connected thereto and embedded in said base wall of said wheel.

6. A reinforcing carrier for molded grinding wheels, said carrier comprising a shallow cup-like structure including a disc adapted to span the base of the wheel, a peripheral flange on said disc tightly encircling the outer periphery of the wheel to form a reinforcing binder in contact therewith, tangs extending inwardly from said flange for interlocking engagement with the wheel, and a shaft-receiving hub fixed to said disc at the center thereof and having surface projections extending into interlocking engagement with the wheel, whereby the aforesaid surface projections and tangs cooperate to retain fragments of the wheel in the event of fracture thereof.

References Cited in 'the file of this patent UNIT ED STATES PATENTS 2,278,301 Bauer Mar. 31, 1942 2,320,130 Harris May 25, 1943 2,397,849 Engeln Apr. 2, 1946

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