Patent GB-749748-A (GB)
Title: Improvements in and relating to abrasive elements such as wheels and discs
IPC: B24D7/00
Filed: 1952-07-28
Abstract: 749,748. Abrasive tools. SIMPSON, H. A. June 10, 1953 [July 28, 1952], No. 19030/52. Class 60 An abrasive element such as a grinding, cutting, polishing or like abrading wheel or disc having working surfaces on one or both of its sides and/or its periphery comprises a base member having applied thereto a substantially homogenous mass of abrasive grains dispersed in softer-thanabrasive fibrous or threadlike material, the whole being bonded together into a rigid or semi-rigid element so that in operation the fibrous or threadlike material is worn down when in contact with the work thus providing sharp cutting abrasive material on the surface of the element. The softer-than-abrasive fibrous or threadlike material may be any material which has interengaged or interkeyed threads which will withstand the tensile stresses imposed on high-speed grinding elements; suitable materials for the purpose are pieces of woven fibrous material, e.g., cotton, jute or asbestos, pieces of natural fibrous materials such as shredded or otherwise crushed wood or asbestos, wads or threads of natural or synthetic materials such as cotton, wool or nylon, impregnated products such as phenol formaldehyde resin bonded glass fibre or vinyl compounds, metallic threads of steel, copper or brass which may be interwoven as in steel gauze or be made threadlike as in expanded sheet metal, or any mixture of these materials. As an example of suitable woven fibres "corset cuttings" may be used. The 'free fibre ends or the threads of these materials are interengaged or interkeyed together in the bonding medium or key into the bonding medium and bind the whole mass together. The bonding medium may be of any suitable material such as natural glues whether animal, vegetable, e.g., rubber latex, or other known glues of this type, or they may be made of synthetic glues such as phenol formaldehyde resin, urea formaldehyde resins, alkyd resins or'vinyl resins. The abrasive materials employed may be natural materials such as sand, emery, garnet or they may be of synthetic materials such as aluminous oxide or silicon carbide. The base member may be of any suitable rigid or'semi-rigid material such as copper, brass, steel, asbestos or other sheets, which may have smooth, roughened, grooved, perforated or other surfaces as desired. In the manufacture of an element, the fibrous or stranded threadlike material is made by cutting up strips or pieces of cut lengths or other stranded threadlike material and thoroughly mixing it to form a mass with the fibres or threads interengaged; the bonding medium in liquid or powdered form is then added to the mass. Abrasive grains are added before, at the same time as, or after the addition of the bonding medium. Lubricants such as camphor, stearates or wax, plasticizers such as phosphites, e.g., tricresyl phosphite, phthalates or the like or a mixture of such materials may be added to the mix. The mix is then applied to the base member, and the element moulded. In a modification, the element may be built up by spraying a layer of bonding medium on the base member and then applying the grain on the fibrous or stranded material, the process being repeated if desired.