US3340652A

US3340652A - Abrasive disc support

Info

Publication number: US3340652A
Application number: US429361A
Authority: US
Inventors: Jr Joseph W Purcell
Original assignee: Merit Products Inc
Current assignee: Merit Products Inc
Priority date: 1965-02-01
Filing date: 1965-02-01
Publication date: 1967-09-12
Anticipated expiration: 1984-09-12

Description

p 12, 1967 J. w. PURCELL, JR 3,340,652

ABRAS IVE DIS C SUPPORT Filed Feb; 1, 1965 I n vemar,

Joseph M Puree/(Jr B, 626., 9.3.3:?

, I/forney United States Patent 3,340,652 ABRASIVE DISC SUPPORT Joseph W. Purcell, Jr., Los Angeles, Calif., assignor to Merit Products, Inc., Los Angeles, Calif., a corporation of California Filed Feb. 1, 1965, Ser. No. 429,361 6 Claims. (Cl. 51-376) This invention relates to an abrasive disc support or back-up pad.

The type of disc support to which this invention relates comprises a circular body member which is customarily formed of resilient material molded on a flat circular piece of fabric. The resilient material is customarily molded around and bonded to a central core or hub. The hub carries means for securing the disc support to an arbor for rotation and may also carry means for removably holding a circular disc of abrasive material.

Devices of this type which are now in use have a structural weakness in that during rotation and flexing of the disc support in use, the resilient material along the fiat portion of the disc support directly adjacent to the hub tends to separate from the hub. This is generally the weakest part of the structure because of the difficulty of bonding elastomeric material to metal.

It is accordingly the primary object of the present invention to provide an improved abrasive disc support of the type described.

In essence, my invention contemplates strengthening the weak area where the resilient material is joined to the hub by providing the fabric with a plurality of slits rather than a central circular opening. The slitted portion is then bent upwardly to form a plurality of segments which extend along the outer wall of the hub. An annular ring is then mounted around the segments to hold them in position and the elastomeric material is then molded around the entire assembly.

The resulting abrasive disc support is substantially stronger than conventional disc supports because the fabric segments and ring act to prevent separation of the elastomeric material from the hub. The disc support is thus stronger and will last substantially longer in use than devices made in the conventional manner.

It is accordingly among the objects of my invention to provide a novel abrasive disc support having all of the advantages and benefits of the structure set forth above and described in further detail hereinafter in this specification.

My invention also comprises such other objects, advantages and capabilities as will later more fully appear and which are inherently possessed by my invention.

While I have shown in the accompanying drawings a preferred embodiment of my invention, it should be understood that the sarne is susceptible of modification and change without departing from the spirit of my invention.

Referring to the drawings,

FIG. 1 is a side elevational view of an abrasive disc support constructed in accordance with my invention;

FIG. 2 is a sectional view of the same, taken along line 22 of FIG. 1;

FIG. 3 is an exploded perspective view showing the annular ring, slitted fabric base and hub prior to assembly;

FIG. 4 is a perspective view showing the annular ring, fabric base and hub after assembly and prior to molding.

A preferred embodiment and method which have been selected to illustrate my invention comprise forming an abrasive disc support from a hub 10, which is customarily formed of metal or other substantially rigid material. The hub generally incorporates holding means 11 at one end thereof for removably holding a circular sheet of abrasive material. The hub 10 also provides means for mount- 3,34%,652 Patented Sept. 12, 1967 ing the disc support on an arbor 12 which is in turn connected to a suitable source of rotation.

The hub 10 is provided with an outer wall having a narrow substantially cylindrical lower portion 13 and a larger substantially frusto-conical upper portion 14. The entire outer wall of the hub 10 may be coated with a suitable composition which acts to improve its bond with the elastomeric material.

The resilient portion of the disc support is preferably formed around a circular base 15, which customarily comprises a circular piece of nylon fabric or other suitable material. Instead of providing a circular opening at the center of the base 15 which fits around the hub 10, I provided the base 15 with a plurality of slits 20, as shown in FIG. 3 of the drawings, which extend radially outwardly from the center a suflicient distance to permit the hub 10 to fit within the slitted portion.

The hub 10 is then inserted through the central slitted portion of the base 15, so that the slitted portion forms a plurality of segments 16 which extend along and directly adjacent to the lower portion 13 and the lower part of the upper portion 14 of the outer wall of the hub 10.

An annular retainer ring 17, which is preferably formed of metal or other substantially rigid material, is then mounted over the base portions of the segments 16. The ring 17 is substantially concentric with and spaced slightly from the cylindrical lower portion 13 of the hub 10, with the base portions of the segments 16 being securely held therebetween.

The retainer ring 17 and the base '15 may also be coated or impregnated with a suitable composition of the type known to the art for improving the bond between them and the elastomeric compound.

The assembly described, which is shown in FIG. 4 of the drawings, is then placed in a mold and the elastomeric compound is molded around it and bonded to it in order to form a complete abrasive disc support as shown in FIG. 1 of the drawings. The resulting disc support or back-up pad is somewhat resilient and is adapted to support a disc of abrasive material for grinding and polishing fiat or slightly contoured surfaces.

The elastomeric compound permeates and becomes bonded to the base 15, forming a thin layer on one side of the base and a much thicker layer on the opposite side of the base. The elastomeric material forms a resilient pad 19, which surrounds the hub 10 and is bonded to the ring 17, the segments 16 and the upper portion 14 of the outer wall of the hub 10.

It will be noted that separation of the pad 19 from the hub 10 is prevented by the segments 16 and retainer ring 17, which strengthen the formerly weak portion of the assembly and provide a longer useful life for the disc support.

I claim:

1. An abrasive disc support comprising a substantially rigid hub, said hub having an outer wall, a circular base having a plurality of segments adjacent its center, said hub being disposed adjacent the center of said base, with said segments extending along the outer wall of said hub, a retainer ring disposed around said hub, said segments being held between said retainer ring and the outer wall of said hub, and elastomeric material bonded to said base, retainer ring and the outer wall of said hub.

2. An abrasive disc support comprising a substantially rigid hub, said hub having an outer wall, a circular base cut adjacent its center to provide a plurality of integral segments, said hub being disposed within the center of said base, with said segments extending along the outer wall of said hub, an annular retainer ring disposed concentrically around said hub, said segments being held between said ring and the outer wall of said hub, and elastoneric material bonded to said base, retainer ring and the outer wall of said hub.

3. An abrasive disc support comprising a substantially rigid hub, said hub having an outer wall, said outer wall having a substantially cylindrical portion, a circular fabric base slitted adjacent its center to provide a plurality of integral triangular segments, said hub being disposed within the center of said base, With said segments extending along the cylindrical portion of the outer wall of said hub, an annular retainer ring disposed concentrically around the cylindrical portion of the outer wall of said hub, said segments being held between said ring and the cylindrical portion of the outer wall of said hub, and elastomeric material forming a resilient pad bonded to said base, retainer ring and the outer wall of said hub.

4. An abrasive disc support comprising a hub, said hub having an outer wall, a base substantially surrounding said hub, said base having a plurality of segments extending along the outer wall of said hub, a retainer ring disposed around said segments and holding said segments adjacent to the outer wall of said hub, and elastomeric material bonded to said base, retainer ring and the outer wall of said hub.

5. An abrasive disc support comprising a hub, said hub having an outer wall, a base substantially surrounding said hub, said base having an integral portion extending along the outer wall of said hub, retaining means disposed around and holding said integral portion adjacent to the outer wall of said hub, and elastomeric material bonded to said base and the outer wall of said hub.

6. An abrasive disc support comprising a hub, said hub having an outer Wall, a base having a portion thereof extending along the outer wall of said hub, and elastomeric material bonded to said base and the outer wall of said hub.

References Cited UNITED STATES PATENTS 250,003 11/1881 Rogers 51379 407,248 7/1889 Rogers 51401 3,119,208 1/ 1964 Gianatasio 51-405 3,166,877 1/1965 Reames 51378 3,239,971 3/1966 Freerks 51-379 ROBERT C. RIORDON, Primary Examiner.

D. G. KELLY, Assistant Examiner.