Patent GB-696985-A (GB)
Title: Method and apparatus for contouring surfaces
Inventor: PEARSE JOHN PHILLIP
IPC: B24B21/00
Filed: 1951-07-02
Abstract: 696,985. Abrasive band machines. LIBBEYOWENS-FORD GLASS CO. July 2, 1951, No. 15583/51. Class 60. A method of reproducing surface contours from a model F on to the surface of a work piece G comprises bringing the work surface into contact with an abrasive surface 83 moving in two directions simultaneously over and in contact with the surface of the model, neither the model nor the work being rotated during the operation. The model is secured by clamps 288 on a table 19 which is mounted on beams 18 projecting from a column in the form of four uprights 11; the table 19 is mounted on a central ball-joint 20 and may be fixed at a desired inclination by adjusting screws 21 provided at its corners. The workpiece G, which may be a mould for the bending of glass sheets, is secured by clamps to the underface of an open frame 17 which is hinged at 51 to a housing 44 having sleeved portions 45, 46 whereby it may slide on the uprights 11, dust covers 50 being provided above and below each sleeve. Swing- ing movement of the frame 17 between horizontal and upper vertical positions is effected by a hydraulic cylinder 58 pivoted on the housing 44 and having its piston rod 66, Fig. 10, connected to an extension 69 of the frame. An adjustable bolt 77 co-operates with the extension 69 to limit downward movement of the frame beyond the horizontal, and an adjustable cam 70 on the extension 69 is effective when the frame is substantially horizontal to actuate a valve 73 in the presure fluid circuit of the cylinderder 58 and so brake movement of the frame. Vertical movement of the housing 44 and frame 17 is effected by screw-threaded shafts 81, 82 which are journaled in the column and engage screw-threaded sleeves 106 in the housing 44. The shafts 81, 82 are carried in bearings 114 in a cross bar 12 at the top of the column so as to hang therefrom, and are driven through gearing 84, 85, Fig. 24, either from an electric motor 87 or hand-wheel 86. The abrasive surface 83 is an endless band, Figs. 1 and 3, trained over pulleys 119, 120, 121, 122 on a carriage D movable on rails 175, to and from the column. Movement of the carriage is effected by a hydraulic cylinder 180 which is mounted on the machine bed and has its piston rod 181 linked to the carriage. Cams 185, 186, Fig. 24, adjustably mounted on the carriage cooperate with limit switches 192, 193 on the bed for automatically reversing the direction of movement of the carriage when the band is operating. The band 83 passes over a tensioning pulley 121 to two vertically-adjustable pulleys 119, 120 and then to the pulley 122, Fig. 3, which is driven by an electric motor 171. The pulleys 119, 120 are each mounted on a slide 133 adjustable vertically on a post 126 on the carriage, and the shaft of each pulley is mounted on a block which is hinged to the slide 127 so that the pulley may be adjusted to desired angular position. The pulley 121 is mounted on a pivoted plate 158 which is urged in a direction to tension the band by the piston rod 167, Fig. 24, of a hydraulic cylinder 163. In some cases, the pulleys 119, 120 may be dispensed with, and the band 83 is then led directly between the pulleys 121, 122. The carriage D is provided with a cover 286 which shields the cylinder 180 against falling abrasive particles, and a platform 287, upon which the operator may ride when it is desired to inspect the operation. The hydraulic cylinders 58, 167, 180 together with solenoid-valves 225, 271, are arranged in circuit as shown in Fig. 24, with a pump 210 driven by a motor 209. The motors 87, 171, 209 are actuated by relay switches 237, 256, 213 under the control of switches 198, 199, 200, 201 which are arranged on a panel on the machine with other switches for controlling the solenoid valves 225, 271. The solenoid valve 225 controlling the hydraulic cylinder 58 is actuated by one of two switches 196, 197 according to the desired direction of swing of the frame 17, and the solenoid valve 271 controlling the hydraulic cylinder 180 is actuated by one of two switches 202, 203 according to the desired direction of travel of the carriage D or by the cams 186, 187 cooperating with the limit switches when the carriage is to be automatically reciprocated. With the carriage D withdrawn, the model and workpiece are clamped in position, the table 19 is suitably inclined on its ball support, and the position of the frame 17 adjusted by the hydraulic cylinder 58 and motor 87. The hydraulic cylinder 180 is then operated by closing the switch 202 to move the carriage D to operative position, the frame 17 is lowered by the motor 87 until the band 83 is in contact with both the model and workpiece, and the motor 171 is energised to drive the band. The circuit is then set to cause automatic reciprocation of the carriage D and band, and the handwheel 86 is progressively turned to advance the workpiece on to the band. The surface of the model may be rubbed with wax, and the back of the band may be coated with soap. Abrasion may be effected with the band dry, sprayed with water, or coated with oil.