US 3860400 A
Abrasive articles and methods of making same wherein a carrying sheet preferably in the form of a wire mesh or like perforated structure is embedded in a backing member in a manner whereby only spaced portions of the sheet are exposed on one surface of the backing member and abrasive particles are secured only to these exposed portions of the sheet.
Claims available in
Description (OCR text may contain errors)
United States, Patent Prowse et al.
[ Jan. 14, 1975.
FLEXIBLE ABRASIVE COVERINGS Inventors: Derek Henry George Prowse;
Stephen Derek Prowse, both of Batts Hill, Redhill, Surrey, England Assignee: D. H. Prowse and Company Limited,
Surrey, England Filed: July 17, 1972 Appl. No; 272,116
Foreign Application Priority Data References Cited UNITED STATES PATENTS 7/1905 (iorton 5l/DlG. 19
Gorton 5l/DlG. l9 Benner et al. 51/307 Taylor 51/299 Sternfield et al. Sl/295 Robie 51/296 Anthony et al. 51/293 Hoover 51/295 Hurst 5l/293 Mattia et al. 5l/309 Primary ExaminerDonald J. Arnold ABSTRACT Abrasive articles and methods of making same wherein a carrying sheet preferably in the form of a wire mesh or like perforated structure is embedded in a backing member in a manner whereby only spaced portions of the sheet are exposed on one surface of the backing member and abrasive particles are secured only to these exposed portions of the sheet.
18 Claims, 3 Drawing Figures FLEXIBLE ABRASIVE COVERINGS This invention relates to abrasive articles and finds application in diverse fields such as grinding wheels or discs, flexible abrasive coverings or sheets or endless abrasive belts.
One object of the invention is to provide a method and means whereby abrasive particles such as diamond particles can be plated onto a sheet of flexible material for example a sheet of flexible mesh in such a manner that the flexibility of the sheet is substantially unimpaired and so as to produce a flexible abrasive article which can be used to advantage in the surface treatment of irregular surfaces for example in grinding irregular stonework.
The invention provides an abrasive article comprising abrasive carrying material combined with nonabrasive carrying material in a manner whereby spaced portions only of the carrying material are exposed from the non-carrying material on one surface of the article and abrasive particles secured only to said exposed portions of the carrying material.
The invention also provides a method of manufacturing an abrasive article comprising combining abrasive carrying material with non-abrasive carrying material exposing spaced portions only of the carrying material from the non-carrying material on one surface of the article and securing abrasive particles only to said exposed portions of the carrying material.
By securing the abrasive particles only to the exposed portions of the carrying material, control of the distribution of abrasive particles over an area can be obtained. Further, where the carrying material is a flexible mesh or perforated sheet, and the abrasive is in the form of diamond particles to be plated onto the mesh, by exposing only portions of the mesh on one surface of the backing member and plating the diamond particles to these portions only, the plating process does not substantially affect the flexibility of the mesh intersections, so that if a flexible backing member is used, a flexible sheet of diamond plated mesh can be obtained.
The abrasive carrying material which is preferably in sheet form having a discontinuous surface may be flat or bent for example the sheet may be formed into a tube or cylinder which is then combined with backing member material and abrasive to form either a solid cylindrical or a tubular abrasive article respectively. Dependent on the application required the abrasive carrying material may be metallic or non-metallic, flexible or rigid and may be perforated or imperforate, the latter having for example a pattern embossed thereon or being corrugated, to provide a discontinuous surface to facilitate exposure of portions only of the sheet on one face of the non-abrasive carrying material or backing member. Examples of suitable abrasive-carrying materials are metallic or non-metallic mesh or screen structures or perforated or expanded sheets.
The non-abrasive-carrying material may be flexible or non-flexible and may comprise a synthetic plastics or natural material such as rubber or latex. Where the abrasive particles are to be electroplated onto the carrying material, the non-earrying-or backing member material should be non-conducting. Examples of suitable materials for synthetic plastics backing members are polypropylene, acrylic butadiene styrene, styrene acrylic nitride, Delvin (aeetal resin compositions manufactured by DUPONT & CO.), nylon, Surlyn (polymeric resin compositions, ionomers based on ethylene manufactured by DUPONT & CO.), or fibre glass or other resin compositions.
Numerous techniques may be employed for combining the materials so that only portions of the carrying material are exposed on one surface of the noncarrying material. For example, a sheet of carrying material may be embedded in a backing member by extrusion or by pressing the sheet into the backing member, i.e. by vulcanization. The sheet may be coated or sprayed with backing member material or the sheet can be dipped into molten backing member material or simply adhered to the backing member with solvent or adhesive.
The abrasive particles may comprise diamond particles either natural or synthetic, cubic boron nitride, tungsten carbide, glass, sand or any other abrasive or combination thereof or the abrasive particles may comprise conglomerates of abrasive particles impregnated into a carrying medium. To attach the abrasive particles to the exposed portions only of the carrying material it is preferred, particularly in the case of a diamond abrasive which it is envisaged will be the most useful form of abrasive for articles according to the invention, to plate the particles tothe carrying material, by conventional electroplating techniques where a metal carrying sheet is used with a non-conductive backing member or for a non-metallic carrying sheet first by chemically depositing a metal onto the exposed sheet portions followed by an electroplating process for the abrasive particles.
The invention will now be described by way of example with reference to the accompanying drawings all of the Figures of which show cross-sections through different forms of abrasive particles.
FIG. 1 shows carrying material in the form of a sheet of wire mesh 1 embedded in non-carrying material in the form of a backing member 2 of say plastics material in such a manner that only regularly spaced peak portions 3 of the mesh at its intersections are exposed on the upper surface of the backing member. These exposed portions of the mesh are plated with abrasive particles 4. This form of the invention is useful for grinding wheels or as an abrasive covering or belt, if the backing member is flexible.
In the construction shown in FIG. 2, a raspsection perforated sheet 5 is embedded in a backing member 6 so that only those portions of the sheet around the perforations are exposed on the upper surface of the backing member and again, only these exposed portions are plated with abrasive particles 7, eg diamond particles.
FIG. 3 shows a tubular form of abrasive article, such as an abrasive roller or a tubular bead to be threaded for example onto a saw wire, and comprising a tubular backing member 8 with a tube of wire mesh 9 embedded therein so that only portions of the mesh at its intersections are exposed on the outer peripheral surface of the backing member. These exposed portions are again plated with abrasive particles 10. The mesh may be pressed into the backing member or the backing member may be extruded with the mesh.
EXAMPLE I A rigid grinding wheel was made from a body member of acrylic butadiene styrene (ABS) having an abrasive covering constructed in accordance with the invention. To this end, a sheet of mild steel mesh l/l6 inch thick with 14 apertures per linear inch and a wire diameter of 18 thousandth of an inch was embedded in a 1/16 inch thick backing member sheet also of ABS. The embedding process was performed in a press with a heated platen and was carried out until the mesh and backing member surfaces were substantially flush. Then, the backing member with the embedded mesh was adhered with solvent to the wheel body and the operative surface trimmed with a conventional grinding wheel to ensure exposure from the backing member only of spaced portions of the mesh at the mesh intersections. The wheel body, with an electrode attached to the mesh was then admitted to a conventional nickel electroplating bath containing diamond grit particles of 170/200 grit size and the grit particles were thus plated only onto the exposed portions of the mesh.
EXAMPLE II To obtain a flexible abrasive covering material, useful for example as a peripheral covering for a grinding wheel or as a covering for a flexible disc grinder, a metal mesh as outlined in Example I, was embedded in a Ill 6 inch backing sheet of a flexible plastics material in this case polypropylene by the same method used in Example I. The operative surface was again trimmed to ensure correct mesh exposure and the resultant covering material was then treated in an electroplating bath as indicated in Example I to plate diamond gint particles only to the exposed mesh portions. This flexible covering can then be combined with a compressible backing such as a rubber backing or a noncompressible metallic backing to form a grinding wheel.
It will be appreciated that use of the invention allows the distribution of abrasive particles over a required area to be accurately controlled by controlling the points of exposure of the carrying sheet from the backing member, by suitable choice of the sheet configuration and further, where non-abrasive areas are required on an abrasive surface, these can be obtained by conventional masking techniques during the plating process.
Further, whilst in the accompanying drawings, the exposed portions of the abrasive carrying material are, for the sake of clarity, shown as projecting slightly from the surface of the non-carrying material, this is not essential. The exposed portions of the carrying material can be flush with the surface of the non-carrying material or even depressed from said surface. Also, whilst the specification describes articles with abrasive particles on one surface only, it is within the scope of the invention to provide an article with exposed portions of 4. An article as claimed in claim 3 wherein said sheet is perforated.
5. An article as claimed in claim 4 wherein said sheet comprises a mesh structure.
6. An article as claimed in claim 5 wherein said exposed portions include intersecting portions of the mesh structure.
7. An article as claimed in claim 1 wherein said sheet consists of an electrically conducting material.
8. An article as claimed in claim 1 wherein the backing material is flexible.
9. An article as claimed in claim 1 wherein the backing material is non-electrically conducting.
10. An article as claimed in claim 9 wherein the supporting material is a synthetic resinous material.
1 1. An article as claimed in claim 1 wherein the abrasive particles include diamond particles.
12. An article as claimed in claim 1 wherein the abrasive particles are plated onto said exposed portions of the sheet.
13. A method of manufacturing an abrasive article comprising embedding a metallic sheet within a backing material so as to expose spaced portions only of the sheet on a surface of the backing material and bonding abrasive particles to said exposed portions of the sheet. 14. A method as claimed in claim 13 wherein the sheet is pressed into the backing material.
15. A method as claimed in claim 13 wherein the backing material is a synthetic resinous material and shaped by extrusion along with said sheet.
16. A method as claimed in claim 13 wherein the sheet is embedded in said backing material by applying the material in liquid or molten form to the sheet.
17. A method as claimed in claim 13 wherein said surface of the article is machined to expose said portions of the sheet.
18. A method as claimed in claim 14 wherein the abrasive particles are secured, to the sheet by a plating process.