Arbors and fasteners to afford two forms of easy/quick change mounting for abrasive discs
An attachment structure for a coated abrasive finishing article such as a disc having a central aperture formed therein. The attachment structure may be in a form to be reused indefinitely and in such form includes a nut having a flange engaging the abrasive particles on the disc and a body extending through the central aperture and terminating in an externally threaded shank adapted to be received by the female threads on a drive member. The apparatus may also be in a form to be disposable along with the spent disc. In such form, the apparatus includes a similar nut formed of plastic material which is secured in place on the abrasive disc by a retention member such a washer which is secured to the body of the nut by an interference fit on the side of the disc opposite the abrasive particles.
This invention relates generally to abrasive finishing articles and more particularly, to a mounting structure for attaching coated abrasive finishing articles to the drive member of a power tool and to a coated abrasive finishing article with the mounting structure attached thereto.
DESCRIPTION OF THE PRIOR ARTThe use of rotatably driven abrasive finishing articles and particularly coated abrasive finishing articles such as discs is widespread and familiar in our industrial society. Traditionally, such an abrasive disc is removably attached by way of a hub assembly including a disc support pad to a power tool. When the hub is rotated, the disc rotates with it permitting the moving disc abrasive surface to effectively finish the surface of work pieces. A variety of hub structures have been used in the prior art to secure the abrasive finishing disc to the power tool.
The earliest and very common of such structures includes a support pad having a reinforced central aperture arranged to be engaged over the threaded end of the rotary shaft of the power tool. The abrasive finishing disc is placed on the flat surface of the pad and a flanged nut is turned down onto the threaded end of the rotary shaft protruding through the disc. When the nut is tightened, the flange lays flush against the abrasive surface of the disc and clamps the disc to the support pad.
This traditional mode of attaching the abrasive finishing disc to the rotary power tool has two major disadvantages. The first of these is that in engagement of the rotating finishing disc against the work piece, a large amount of torque is imparted to the hub which tends to tighten the nut onto the threaded shaft of the power tool making it quite difficult to remove the nut in order to replace the disc after it is spent and usually involves the use of tools. In many heavy industrial applications, such abrasive discs have to be replaced quite often. As a result, when considering the number of power tools which may be in use at any given time, there is an excessive amount of downtime necessitated by such disc replacement. The second disadvantage is that the flange of the nut extends onto the abrasive surface of the finishing disc and the worker must be quite careful to prevent the flange on the nut from engaging the work piece which in most cases would impart damage to the work piece.
In order to avoid the problems above referred to, a quick release abrasive finishing disc hub was developed and is most clearly shown in U.S. Pat. Nos. 3,667,169 and 3,667,170. As is disclosed therein, an adapter is provided which is adhesively adhered to the back surface of the abrasive finishing disc. One form of such adapter includes a raised boss having a central aperture whose rim is turned inward and shaped to form a screw thread which receives the threaded end of a stud attached to the power tool or the end of the power tool shaft. Another form is a threaded stud which engages a threaded bore on the power tool shaft. This allows the user to attach or remove the abrasive disc to the power tool rather quickly. It is apparent that through the utilization of such devices, the attaching structure is disposable along with the spent disc. As above noted, the attaching structure is an adapter formed to have a screw thread and is adhesively secured to the back of the coated abrasive disc. Such structures increase the cost of the materials and labor used in the abrasive finishing process.
In view of the foregoing disadvantages of the prior art coated abrasive finishing disc mounts, it is desirable to provide a mounting device for coated abrasive finishing articles and particularly a coated abrasive finishing disc which is reusable or expendable and will provide the ability for the user to quickly and easily remove and mount abrasive finishing discs upon a portable power tool without the need for wrenches, screwdrivers, or other tools with or without the attachment of external adapters or other attachment devices directly to the abrasive finishing discs.
A typical attachment of the type above referred to for securing a coated abrasive disc having a central aperture to the power tool with a nut having a flange is shown by the patent to G. L. Bryson, U.S. Pat. No. 2,699,020. An additional type of quick change structure in addition to the patents above referred to which includes an adapter secured to the abrasive discs is shown by the patent to Field, U.S. Pat. No. 3,653,858.
SUMMARY OF THE INVENTIONA disposable, reusable mounting apparatus for rotatably securing a coated abrasive finishing article to the drive member of a power tool which includes a support member and a nut adapted to extend through an aperture in the finishing article for engaging the finishing article with the power tool which comprises an outer surface on the body of the nut which is adapted to engage an edge of the aperture through the finishing article in an interference fit and an externally threaded shank for engagement with the power tool drive member, a support pad is provided defining a centrally located aperture and a face to engage the abrasive finishing article with the support pad having a reduced thickness region adjacent and surrounding the aperture therethrough. The support member further includes a hollow externally threaded cylinder having an outwardly extending flange at one end thereof and a compression ring. The support pad is secured between the flange and the compression ring to secure the support pad upon the cylinder. The end of the cylinder having the flange defines a recess to receive a flange extending outwardly from one end of the nut so that when assembled in operational configuration, the flange on the nut is below the abrasive finishing article surface so that it cannot engage a work piece during use.
In the reusable mounting apparatus of the present invention the mounting nut includes an irregular surface on the body of the nut which is adapted to engage an edge of the aperture through the finishing article in an interference fit and when the coated abrasive finishing article is spent the nut may be popped out of the aperture in the finishing article and then reused with a new finishing article by inserting the nut through the central aperture therein.
In the disposable mounting apparatus of the present invention the nut is formed of a plastic material and further includes a retention member which engages the body of the nut immediately adjacent the finishing article in an interference fit to secure the nut to the finishing article with the combination of the nut and the finishing article being disposed of when the finishing article is spent.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring now more particularly to
If desired, an additional backing member or disc 50 may be provided along with the support pad 32 to provide additional rigidity. Depending upon the application and the rigidity desired, the additional backup disc 50 may be constructed of metal. Under those circumstances, it may also be desirable to provide an elastomeric washer 52 which is seated between the metal disc 50 and the compression ring 46 to assist in securing the back pad and supporting discs in proper relation to provide the support desired for the abrasive finishing disc 10.
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The completed structure of the disposable abrasive finishing article is shown in
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There has thus been disclosed a mounting device for a coated abrasive finishing article in a form which may be reused indefinitely and which permits easy attachment and detachment by hand without the use of tools for the replacement of spent abrasive discs. Alternatively, the mounting device may be in a form which is permanently secured to the disc and discarded therewith when the disc is spent. The mounting device is constructed in such a manner that the nut for attaching the abrasive disc to the support member is recessed below the surface of the abrasive disc and thus will not contact a work piece during use.
Claims
1. A mounting apparatus for rotatably securing a coated abrasive finishing article (10) having a first surface (12) coated with abrasive material and a second uncoated surface (14) and defining a centrally located first aperture (16), having an edge (24) therethrough, to a power tool drive member (30) which includes a support member having a support pad (32) for engaging said second surface, a nut (18) having a body extending through said aperture for threadably engaging said power tool and said body having an outwardly extending first flange (20) at one end engaging said first surface characterized by:
- the body of said nut having (a) an outer surface (22) adapted to engage said edge (24) of said aperture (16) in a substantially interference fit, and (b) an externally threaded shank (26) for engagement with said power tool drive member (30);
- the support pad defining a centrally located second aperture (35) therethrough and having a face (34) for engaging said second surface, said pad having a reduced thickness region adjacent and surrounding said second aperture; and
- said support member further including a hollow externally threaded cylinder (42) having a second outwardly extending flange (36) at one end thereof and a compression ring (46) defining internal threads, said second flange being received within said reduced thickness region and said compression ring being threadably received on said external threaded cylinder to secure said support pad upon said cylinder, said one end of said cylinder defining a recess (64) for receiving said first flange so that when assembled in operational configuration on said power tool, said flange is below said first surface so as not to engage a work piece.
2. A mounting apparatus as defined in claim 1 wherein said nut is formed of a metal material and is adapted to be reused after the coated abrasive finishing article is spent.
3. A mounting apparatus as defined in claim 2 wherein said outer surface is irregular and is formed by a plurality of alternating ridges and grooves.
4. A mounting apparatus as defined in claim 3 wherein said ridges are substantially parallel to the axis of said body and when said nut is inserted through said first aperture said ridges cut into said edge of said first aperture to form said substantially interference fit.
5. A mounting apparatus as defined in claim 4 wherein said nut may be popped out of said first aperture after said coated abrasive article is spent and may be inserted into a subsequent coated abrasive article for use.
6. A mounting apparatus as defined in claim 1 wherein said hollow cylinder includes a through bore defining a recess adjacent the other end thereof, and an “O” ring seated within said recess for engaging the drive member to assist in retaining said support member on said drive member when coated abrasive finishing articles are changed.
7. A disposable coated abrasive finishing article (10) including a disposable mounting apparatus for rotatably securing the same to a power tool drive member (30) and having a first surface (12) coated with abrasive material and a second uncoated surface (14) and defining a centrally located first aperture (16), having an edge (24) therethrough, said power tool drive member (30) including a support member having a support pad (32) for engaging said second surface, a nut (18) having a body extending through said aperture for threadably engaging said power tool and said body having an outwardly extending first flange (20) at one end engaging said, first surface characterized by:
- the body of said nut having (a) an outer surface (22) having a first diameter (d1) and adapted to engage said edge (24) of said aperture (16) in a substantially interference fit, and (b) an externally threaded shank (26) for engagement with said power tool drive member (30);
- a retention member (78) defining a second aperture therethrough having a second diameter (d2), said second diameter being no larger than said first diameter; and
- said retention member (78) surrounding said outer surface of said body and engaging said second uncoated surface of said abrasive article, said retention member at said second aperture engaging said outer surface (22) in an interference fit.
8. A disposable abrasive finishing article as defined in claim 7 wherein said nut is formed of a plastic material.
9. A disposable abrasive finishing article as defined in claim 8 wherein said plastic material is extruded polyvinylchloride and said threaded shank includes rolled threads.
10. A disposable abrasive finishing article as defined in claim 8 wherein said second diameter is smaller than said first diameter.
11. A disposable abrasive finishing article as defined in claim 7 wherein said abrasive finishing article surrounding said first aperture is symmetrically formed in a direction toward said second surface.
12. A disposable abrasive finishing article as defined in claim 11 wherein said support member defines a recess therein and said symmetrically formed portion of said finishing article is adapted to seat within said recess.
13. A disposable abrasive finishing article as defined in claim 7 wherein said retention member is a flat washer.
14. A disposable abrasive finishing article as defined in claim 13 wherein said second diameter is smaller than said first diameter.
15. A disposable abrasive finishing article as defined in claim 14 wherein said finishing article surrounding said first aperture is symmetrically formed in a direction toward said second surface and said flat washer is canted to follow said second surface.
Type: Application
Filed: Jan 6, 2004
Publication Date: Jun 21, 2007
Inventor: Joseph MacKay (San Diego, CA)
Application Number: 10/538,373
International Classification: B24D 17/00 (20060101);