Expandable Unitary Quick Mount Abrasive Discs and Support Pad Therefor
The combination of an abrasive finishing device and a support pad therefor. The support pad includes circular plastic plates formed to define a depressed center. A fastening member permanently affixed to the abrasive finishing article is attached in such a manner as to form a depressed center section for the abrasive finishing article which is received within the depressed center section of the support pad.
This application is a National Stage of International Application No. PCT/US06/008852, filed Mar. 13, 2006, which claims the benefit of U.S. Provisional Patent Application No. 60/662,710, filed Mar. 14, 2005 and U.S. Provisional Patent Application No. 60/680,756, filed May 9, 2007. The disclosures of the above applications are incorporated herein by reference.
FIELD OF THE INVENTIONThis invention relates generally to abrasive finishing articles and, more particularly, to the combination of an abrasive disc support pad and a disposable abrasive finishing disc in which the securing member affixed to the disposable abrasive finishing disc is disposed within a depressed center so that the securing member is entirely below the surface of abrasive finishing particles contained on an abrasive disc.
BACKGROUND OF THE INVENTIONIn the use of rotatably driven abrasive finishing articles and particularly coated abrasive finishing articles including non-woven material, such abrasive finishing articles are adapted for use on a wide range of air and electric powered tools. Traditionally, such an abrasive or non-woven material finishing article are discs removably attached by way of a support pad assembly to a power tool. When the support pad assembly is rotated, the disc rotates with it permitting the moving abrasive disc surface to effectively finish the surface of a work piece. A variety of hub structures have been used in the prior art to secure the abrasive finishing discs 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 a 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 by engagement of the rotating finishing disc against the work piece a large amount of torque is imported 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. A second disadvantage is that the flange of the nut extends above the surface of the abrasive material on the finishing disc and the workers using the disc 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. Such severely limits the surface area of the abrasive finishing material on the abrasive finishing disc which may be used in finishing the work piece.
To overcome these problems, abrasive finishing discs were developed wherein a fastener was adhesively secured to the back surface of the abrasive finishing disc. One such fastener included a raised boss having a central aperture whose rim is turned inward and shaped to form a screw thread (referred to as a type R fastener) which receives the threaded end on a molded rubber support pad. Another such fastener is a threaded stud which is received by a female thread disposed in a molded rubber support pad (referred to as a type S fastener). These structures are allowed the user to attach and remove the abrasive disc to the support pad rather quickly. The necessity of utilizing adhesive materials to secure the fastener to the abrasive finishing disc obviously increased the manufacturing costs both as a result of the increased amount of material and labor.
In view of the foregoing disadvantages of the prior art, it is desirable to provide a support pad and a disposable abrasive finishing disc which includes a structure such that the device for attaching the disc to the support pad is disposed in a depressed center section of the abrasive disc in a manner such that it is entirely below
w the surface of the abrasive material. The support pad must also include structure for receiving the attaching apparatus secured to the abrasive disc so that it is capable of receiving the depressed center portion of the abrasive finishing disc. It is also desirable that the disc and the fastening member secured thereto be formed in such a manner that the disc can be disposed of when the abrasive material has been used. It is also desirable that the abrasive finishing disc may be quickly and easily removed and a new disc attached without the necessity of utilizing tools and without the attachment of any external adapters or other devices to accomplish that purpose.
SUMMARY OF THE INVENTIONThe combination of an abrasive disc support pad and a disposable abrasive finishing disc comprising a support pad which includes at least one flat circular plate formed to provide a depressed center along with a support base having an outwardly extending flange to seat against the plate, a body having an internally threaded barrel and a base ring which extends outwardly and downwardly to form a cup shaped member adapted to receive and/or form the depressed center of the plate along with an abrasive finishing device with includes a circular disc of abrasive finishing material defining a depressed center and a fastener member formed of malleable material secured to the circular disc by upsetting a portion of a shaft extending therethrough to permanently secure the circular disc between a flange and the upset shaft with the flange entirely disposed below the surface of the abrasive finishing material.
The present invention provides an abrasive finishing disc having a fastener affixed thereto in such a manner that the abrasive finishing disc forms a depressed center such that the flange which holds the abrasive disc to a support pad is disposed completely below the surface of the abrasive finishing material which forms a part of the abrasive disc thereby maximizing the amount of surface area which is usable. The abrasive discs may be made of coated cloth or fiber or non-woven abrasive material as is well known in the art. The fastener device includes a shaft having male or female threads for attachment to a support pad. The support pad includes a depressed center area which cooperates to receive the depressed portion on the abrasive disc so that when the disc is fastened in place for use on the support pad, the fastener flange remains disposed below the abrasive finishing particle surface. The depressed center for the support pad is created by forming plates preferably formed from molybdenum disulfide filled nylon sheet but may also include other materials such as a lamination of molybdenum disulfide filled nylon and cloth supported neoprene plastic. Through utilization of such materials the plastic plates included as part of the support pad have a depressed center configuration when assembled on the support pad body. The degree of flexibility of the support pad may be determined by the number, thickness, diameter and the relative position of the plates contained in the pad to provide the desired amount of flexibility depending upon the particular application to which the abrasive finishing device is being applied.
By reference to the drawings, and more particularly to
The structure of the support pad 30 as illustrated in
To form the abrasive finishing article and make it ready for use on a support pad the fastener 68 is inserted through the opening 64 until the flange is seated against the abrasive finishing surface 66. This combination is then inserted into an assembly fixture which is formed to have a cavity therein. The disc 62 is seated on the fixture with the surface 76 around the opening 64 disposed adjacent the cavity. A force is then applied as shown at F against the flange 70 to force the fastener into the cavity and against a member of the assembly fixture which will upset the upper port of the reduced diameter portion 72 as is illustrated at 78 in
By reference now more particularly to
Through the utilization of the molybdenum disulfide filled nylon (or other plastic material) plates, the resulting structure is lighter in weight than the support pads of the prior art. In addition to the variable flexibility thereof, the support pad as illustrated in the present invention may be rotated at a much higher rate of speed than that of the prior art molded rubber pads currently being used. If the prior art molded rubber pads are rotated at the same speed as the support pad of the present invention, they would immediately deteriorate and effectively explode throwing particles thereof into the surrounding area. As is illustrated and has been described in detail above, the fastener surface holds the abrasive disc from the abrasive surface thereof in such a manner that the retaining flange on the fastener is below the operating surface of the abrasive disc thus providing a larger useful area and also precluding contact of the work piece by the fastener. As above illustrated, the abrasive disc is held in place and is gripped both by the upset portion of the fastener against the disc retaining flange and in addition when the abrasive finishing article is affixed to the support pad the disc retaining flange captures the disc and presses it against the depressed center area of the body of the support pad.
There has thus been disclosed a support pad having a depressed center section which receives a complimentary depressed center section of an abrasive disc which is affixed thereto in such a manner that the fastening member is totally disposed below the operating surface of the abrasive disc to preclude contact thereof with the work piece. The abrasive finishing disc may be quickly and easily removed from the support pad and when spent may be discarded.
Claims
1. The combination of an abrasive disc support pad and a disposable abrasive finishing disc comprising:
- (1) A support pad including: (a) at least one circular plate defining a centrally disposed opening therethrough and having first and second surfaces, (b) the plate surrounding said opening having a curved profile so that said first surface surrounding said opening is concave and said second surface surrounding said opening is convex to thereby provide a circular plate having a depressed center, (c) a support base including a body having an outwardly extending first flange engaging said second surface of said plate, said body defining a centrally disposed opening therethrough, (d) said opening adjacent said first flange defining a cup shaped recess for receiving a central portion of said abrasive disc, (e) a base ring surrounding said body to retain said at least one plate against said first flange;
- (2) An abrasive disc comprising: (a) a circular disc having abrasive finishing material on at least one surface thereof and defining a centrally disposed opening therethrough, the disc surrounding said opening being deformed to define a depressed center in said abrasive finishing material, and (b) a fastener member formed of malleable material including a shaft having a second flange extending outwardly from one end thereof, said second flange being received within said depressed center of said abrasive finishing material, said shaft adjacent said opening in said disc being upset to permanently secure said circular disc between said second flange and said upset portion of said shaft, said second flange being entirely disposed below a working surface of said abrasive finishing material, said shaft being threadably received within said centrally disposed opening of said body.
2. The combination as defined in claim 1 wherein said at least one circular plate is a molybdenum disulfide filled nylon plate.
3. The combination as defined in claim 1 wherein said at least one circular plate is a molybdenum disulfide filled nylon and cloth supported neoprene plate.
4. The combination as defined in claim 1 wherein said base ring is press fitted to an outer surface of said body.
5. The combination as defined in claim 1 wherein an outer surface of said body is threaded and which further includes a collar having an internally threaded opening therethrough and which is threadably received on said outer surface of said body for retaining said at least one plate on said body.
6. The combination as defined in claim 1 wherein said base ring includes a periphery extending away from said base ring and engagement with said at least one plate.
7. An abrasive finishing disc for use with a support pad having a depressed center and a threaded centrally disposed opening therethrough, said disc comprising:
- (a) a circular disc having abrasive finishing material on at least one surface thereof and defining a centrally disposed opening therethrough, the disc surrounding said opening being deformed to define a depressed center in said abrasive finishing material; and
- (b) a fastener member formed of malleable material including a shaft having a flange extending outwardly from one end thereof, said flange being received within said depressed center of said abrasive finishing material, said shaft adjacent said opening in said disc being upset to permanently secure said circular disc between said flange and said upset portion of said shaft, said flange being entirely disposed below a working surface of said abrasive finishing material, said shaft being threadably received within said centrally disposed opening of said body.
8. A support pad adapted to receive an abrasive finishing disc having a fastener affixed centrally, said support pad comprising:
- (a) at least one circular plate defining a centrally disposed opening therethrough and having first and second surfaces;
- (b) the plate surrounding said opening having a curved profile so that said first surface surrounding said opening is concave and said second surface surrounding said opening is convex to thereby provide a flat plate having a depressed center;
- (c) a support base including a body having an outwardly extending flange engaging said second surface of said plate and defining a centrally disposed opening therethrough;
- (d) said opening adjacent said first flange defining a cup shaped recess for receiving a central portion of said abrasive disc;
- (e) a base ring surrounding said body to retain said plate at least one plate against said first flange.
9. The support pad as defined in claim 8 wherein said circular plate is constructed of molybdenum disulfide filled nylon.
10. The support pad as defined in claim 8 wherein said circular plate is constructed of molybdenum disulfide filled nylon and cloth supported neoprene.
Type: Application
Filed: Mar 13, 2006
Publication Date: Oct 16, 2008
Inventor: Joseph MacKay (San Diego, CA)
Application Number: 11/908,491
International Classification: B24D 17/00 (20060101); B24B 27/08 (20060101);