EXPENDABLE UNITARY QUICK MOUNT ABRASIVE DISCS AND SUPPORT PAD THEREFOR
The combination of an abrasive finishing device and a support member therefor. The support member includes a body having a threaded central opening with a flange at one end thereof. A fastening member having a threaded shaft and flange is permanently affixed to the abrasive finishing article by a resiliently deformable retainer press fitted over the threads on the shaft in such a manner that the flange on the fastening member is disposed entirely below the working surface of the abrasive finishing device. The retainer is a washer shaped member having an inner diameter which is less than the outer diameter of the threaded shaft on the fastening member and grips the thread on the shaft.
This application claims priority of U.S. Provisional Patent Application No. 61/003,102 filed on Nov. 13, 2007, and the disclosure thereof is incorporated herein by reference and is a continuation in part of U.S. application Ser. No. 11/908,491 filed Sep. 12, 2007.
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 entirely below the working surface of abrasive finishing particles contained on the abrasive disc.
BACKGROUND OF THE INVENTIONIn the use of rotatably driven abrasive finishing articles and particularly coated abrasive finishing articles and non-woven fibrous abrasive 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 have 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 member and a disposable abrasive finishing disc which includes a structure such that the device for attaching the disc to the support pad is entirely below the surface of the abrasive material. The support member must also include structure for receiving the attaching apparatus secured to the abrasive 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 INVENTIONAn abrasive finishing disc for use with a support member wherein the abrasive disc includes a circular disc having first and second surfaces with abrasive finishing material on at least the first surface, a fastener member including a threaded shaft having a flange extending radially outwardly from one end thereof extending through an opening centrally disposed in the circular disc with the flange engaging the first surface of the disc and the threaded shaft extending beyond the second surface of the disc and a resiliently deformable retainer member press fitted over the threaded shaft, gripping the threads on the shaft and engaging the second surface of the disc with sufficient force to permanently secure the disc between the flange and the retainer member and to cause the flange to be entirely disposed below the first surface of the disc.
The combination of an abrasive disc support member and a disposable abrasive finishing disc comprising a cylindrical body having an outwardly extending flange engaging the disc and defining a centrally disposed threaded opening therethrough. The opening adjacent the flange defining a cup shaped recess for receiving a central portion of the disc and an abrasive disc comprising a circular disc having first and second surfaces with abrasive finishing material on at least the first surface. A fastener member including a threaded shaft having a flange extending radially outwardly from one end thereof extending through an opening centrally disposed in the circular disc with the flange engaging the first surface of the disc and the threaded shaft extending beyond the second surface of the disc and a resiliently deformable retainer member press fitted over the threaded shaft, gripping the threads on the shaft and engaging the second surface of the disc with sufficient force to permanently secure the disc between the flange and the retainer member and to cause the flange to be entirely disposed below the first surface of the disc.
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 three dimensional fibrous abrasive material as is taught in U.S. Pat. No. 5,858,140 or such material having a reinforcing scrim as taught in U.S. Pat. No. 3,688,453. The fastener device includes a threaded 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.
Referring now more particularly to
It should be understood that when the washer 114 is press fitted into place as shown in
By reference now to
There has thus been disclosed an abrasive finishing disc wherein a circular disc of abrasive finishing material is permanently secured by a fastening member which includes a press fitted resiliently deformable retaining member press fitted over a threaded shaft extending from a flange and protruding through a central opening in an abrasive disc, to rigidly and permanently clamp the abrasive disc to the fastener member without the necessity of utilizing adhesives and with sufficient force to cause the flange on the fastener to be disposed entirely below the working surface of the abrasive disc.
Claims
1. An abrasive finishing disc for use with a support member having a threaded centrally disposed opening therethrough, said disc comprising:
- (a) a circular disc having first and second surfaces with abrasive finishing material on at least said first surface thereof and defining a centrally disposed opening therethrough; and
- (b) a fastener member including a threaded shaft having a diameter d1 and having a flange extending radially outwardly from one end thereof, said threaded shaft extending through said centrally disposed opening in said circular disc with said flange engaging said first surface of said disc and said shaft extending beyond said second surface of said disc; and
- (c) a resiliently deformable retainer member press fitted over said threaded shaft, gripping said threads on said shaft and engaging said second surface with sufficient force to permanently secure said disc between said flange and said retainer member and to cause said flange to be entirely disposed below said first surface said disc.
2. An abrasive finishing disc as defined in claim 1 wherein said resiliently deformable retainer member is a washer having an inner diameter d2.
3. An abrasive finishing disc as defined in claim 2 wherein said washer is constructed of a plastic material and diameter d2 is less than diameter d1.
4. An abrasive finishing disc as defined in claim 3 wherein said washer is a polyamide material.
5. An abrasive finishing disc as defined in claim 3 wherein said abrasive disc is constructed of a non-woven fibrous material.
6. The combination of an abrasive disc support member and a disposable abrasive finishing disc comprising:
- (1) a support member including: (a) a cylindrical body having an outwardly extending flange engaging said disc, said body defining a centrally disposed threaded opening therethrough; and (b) said opening adjacent said flange defining a cup shaped recess for receiving a central portion of said abrasive disc; and
- (2) an abrasive disc comprising: (a) a circular disc having first and second surfaces with abrasive finishing material on at least said first surface thereof and defining a centrally disposed opening therethrough; and (b) a fastener member including a threaded shaft having a flange extending radially outwardly from one end thereof, said threaded shaft extending through said centrally disposed opening in said circular disc with said flange engaging said first surface of said disc and said shaft extending beyond said second surface of said disc; and (c) a resiliently deformable retainer member press fitted over said threaded shaft, gripping said threads on said shaft and engaging said second surface with sufficient force to permanently secure said disc between said flange and said retainer member and to cause said flange to be entirely disposed below said first surface of said disc; and (d) said threaded shaft being threadably received within said threaded opening in said cylindrical body.
7. The combination as defined in claim 6 wherein said resiliently deformable retainer member is a washer.
8. The combination as defined in claim 7 wherein said washer is constructed of a plastic material.
9. The combination as defined in claim 8 wherein said washer is a polyamide material.
10. The combination as defined in claim 8 wherein said abrasive disc is constructed of a non-woven fibrous material.
Type: Application
Filed: Nov 11, 2008
Publication Date: Apr 23, 2009
Inventor: Joseph Hartley MacKay (San Diego, CA)
Application Number: 12/269,012
International Classification: B24B 23/02 (20060101);