| 摘要 |
1,011,029. Grinding. OSBORN MANUFACTURING CO. Oct. 23, 1964 [Dec. 13, 1963], No. 43363/64. Heading B3D. [Also in Division B5] An abrasive wheel comprises a flexible body 12, granular abrasive within the body, and a reinforcing skeleton 18 embedded within the body, the skeleton being relatively rigid in a radial direction but laterally flexible thereby to prevent substantially radially outward expansion of the body but to permit an appreciable degree of lateral deformation of the working face of the wheel in use. The body 12 consists of foamed plastic, such as polyurethane, with abrasive grains embedded in an outer annular belt adjacent the peripheral working surface of the wheel. The reinforcing skeleton is embedded in an abrasive-free zone of the body and consists of lightweight laminated fibrous material, such as cardboard. A bore 20 is provided in the skeleton to define the arbor mounting for the wheel, and tags 24, 26 project from each side of the skeleton for abutment against the sides of a mould during manufacture of the wheel. The skeleton is also formed with triangular-shaped extensions 28 and during moulding, the foamed plastic enters the spaces in and between the extensions and also openings 22 to mechanically and chemically key the skeleton in the body. In other embodiments, the skeleton is located in the mould by pins which pass through holes in the skeleton and are of deformable material, such as polypropylene. In the manufacture of the wheel, the skeleton is placed on a stud 54, Fig. 6, upstanding from a bottom plate 42 mounted on a support 44 rotatable by a gear drive 48 from a motor 46, the skeleton being spaced from the bottom plate by the tags or pins. A ring 20 is placed around the skeleton and the foamable plastic material and abrasive placed in the mould which is then closed by a cover 50. The mould is then rotated so that the abrasive is forced outwardly by the centrifugal force and as the plastic material foams it fills the spaces in the skeleton. The material is then left to cure with or without the application of heat. |
