Patent GB-971530-A (GB)
Title: Improvements in or relating to abrading devices
IPC: B24D5/00
Filed: 1963-04-09
Abstract: 971,530. Grinding. CAVITRON ULTRASONICS Inc. April 9, 1963 [April 25, 1962], No. 14040/63. Heading B3D. An abrading device comprises at least one abrading element 19, Fig. 2, having an active surface adapted to be moved relative to a workpiece 28 and a relatively small thickness in a direction normal to the surface, and means 15 applying high-frequency vibrations to the element at the side of the latter opposed to the surface in a direction normal to the latter, the vibrations being applied to the element so as to be transmitted through the element to act on the active surface and enhance its abrading effect. The abrading element may consist of a length of flexible belting which has abrasive grains bonded to its outer surface and is secured to a rotatable body by a clamp 20. The body comprises a plurality of laminations 16 of magnetostrictive material shaped with portions 18 around which are coils 15 connected to slip rings on a shaft 12 of the body. In operation, the coils are subjected to a biased alternating current of high or ultrasonic frequency to cause the body to vibrate radially as it is rotated in contact with a workpiece 28 traversed past the device, the vibrations being transmitted through the element 19 to its active surface. A coolant, such as water, having a rust inhibitor therein, may be supplied to the grinding area through a nozzle 29. In another embodiment, the abrading element is bonded to the body which has the portions 18 and coils 15 separated by rigid portions whereby alternate areas of the element are not subjected to the radial vibrations. In a further embodiment, the body of the device comprises a plurality of laminations 16b, Fig. 4, of high strength material rigidly secured to a flange 30 at a nodal point of a magnetostrictive transducer 32 joined to the flange by a connecting piece 31. Longitudinal vibrations of the transducer are transmitted by the piece 31 to the flange 30 to transmit radial vibrations to the laminations 16b which are diametrically dimensioned to be radially resonant at the frequency of the standing compressional waves transmitted by the transducer, the radial vibrations being transmitted through the element 19b to its active surface. The element may be formed in sections, each of which is bonded to a radially vibrated or rigid portion, and the laminations may be circumferentially staggered as shown in Fig. 6 to provide helical portions H which are radially vibrated separated by non-vibrated portions L. In another arrangement, the abrading element 119, Fig. 7, comprises an abrasive belt entrained about a contact wheel 111 having radially vibrated portions and rigid portions and an idler pulley 134. The belt has projections 142 which are received within the gaps between the radial vibrated portions and the rigid portion of the contact wheel arranged to be driven by an electric motor. The profile of the contact wheel may be straight or curved to produce a desired configuration on the workpiece. The radial vibrations of the contact wheel may be effected as described in relation to Fig. 4 by generating vibrations in an axial direction. In a further arrangement, the abrading element 219, Fig. 10, comprises a thin rigid ring which is driven by a motor-driven roller 242 over an idler roller 243 and a stationary magnetostrictive transducer 245 connected to an acoustic impedance transformer 246 mounted on a frame 244 by a flange 247 at a nodal plane of the longitudinal vibrations. The vibrations are transmitted through the ring 219 to its active surface and also serve to reduce friction between the ring and the transformer 246. In a similar arrangement, the ring is replaced by an abrasive belt and the transformer has an end face has an elliptical, arcuate, straight or contoured cross-section. The abrading device may be in the form of a hone 316, Figs. 16 and 17, having abrading elements 322 secured to portions 319 of the hone alternating with rigid portions 320 of the hone 318. The hone consists of a plurality of laminations 318 secured to a shaft 313 of magnetostrictive material extending within a coil 314 and driven by a belt 312a. The portions 319 are surrounded by coils 321 supplied with biased alternating current at high or ultrasonic frequency to cause radial vibrations to be transmitted through the elements 322 to their active surfaces in engagement with a bore in a workpiece 328, the coil 314 similarly being supplied with alternating current to cause the magnetostrictive effect on shaft 313 to axially vibrate the tool and reduce the rate of wear on the elements 322. An alternative homing tool comprises a stack of laminations 317a, Fig. 18, which carry abrasive elements 322a and are formed with diametrically opposed arms 319a around which are coils 321a for radially vibrating the elements.