GB1142731A - Belt sanding and polishing machine - Google Patents

Abstract

1,142,731. Grinding. CARBORUNDUM CO. 25 Jan., 1967 [16 Feb., 1966], No. 3780/67. Heading B3D. A sanding and polishing machine comprises a pair of spaced pulleys 22, 24, Fig. 2, rotatably mounted on a frame 10 and carrying an abrasive belt 26 for movement in an orbital path, pressure means 46 mounted on the frame for applying pressure against an active run of the belt, a flexible sheet 92, Fig. 4a, supported by the pressure means and having a pad 94 attached to one side thereof, means 128 for displacing selected portions of the pad towards and away from the active run of the belt, and means 108 disposed on the other side of the sheet for permitting flexibility of the sheet and pad in one direction while maintaining substantial rigidity in a direction normal to said one direction. A motor 28 drives pulley 24 for moving the abrasive belt and also drives a pulley 18 around which and a pulley 16 a back-up belt 20 is disposed. The frame is mounted on pedestals 12, 14 between which a conveyer 30 for a removed panel to be sanded is disposed, the conveyer being vertically adjustable by screw jacks 32, 34 driven from a motor 36. A caul assembly 46, Fig. 3, for pressing the belts towards a workpiece is mounted on levers 62 which are movable about pivots 64 on the frame by operation of a fluid motor controlled through a delay mechanism by a switch 56 actuated when a roller 54 engages a workpiece. Rollers 70 on the assembly urge the workpiece against the conveyer. The caul assembly 46 consists of a channel member 72 welded to a plate 74 beneath which is a resilient bag 88 having separate air cells 90 supplied with air at regulated pressure. The flexible sheet 92 is disposed beneath the bag and has secured to its under surface the pad 94 which comprises a pair of nut members 96, 98 between which is a rubber membrane 100 clamped to cover members 76, 78 to prevent dust entering the assembly. The means 108 permitting flexibility in one direction but not of the other of the sheet and pad comprises a corrugated metal strip between the bag and sheet, the corrugations running normal to the direction of movement of the belts so that uniform pressure is applied to the full width of the pad and belts. A canvas cloth 110, Fig. 4a, impregnated with graphite extends below the pad to prevent wear by the belts and is tensioned by screws 116 and vertically adjusted by screws 124. The effective length of the pressure pads is adjustable at each end. Chains 132 are entrained about sprockets 136 at one end of the assembly and at one end are disposed between flanges 84, 86 on the covers 76, 78 and the flexible sheet and are connected to cables 134 which are guided around rollers at the other end of the assembly and connected to the other ends of the chains. A similar arrangement is provided at the other end of the assembly so that adjustment of the chains by rotation of the sprockets deforms the inflatable bag so that a portion only of the pad presses against the belts. Pointers 166 are connected to the chains to indicate the effective length of the pad.