Patent GB-1009153-A (GB)
Title: Belt sanding machine
IPC: B24B21/00
Filed: 1964-03-24
Abstract: 1,009,153. Grinding. S. KNUPPER. March 24, 1964 [March 26, 1963; March 7, 1964], No. 12393/64. Heading B3D. A belt-sanding machine comprises two endless rotating belts having their operative portions facing each other and in an approximately vertical plane, at least one of the belts being displaceable perpendicularly to its sanding surface and both belts being inclined obliquely at approximately the same angle in the feed direction of the workpiece. The belts 7, 33, Figs. 1 and 2, have their operative faces opposed for abrading the faces of a workpiece 15 which is fed by a chain drive 38 between the belts and are entrained about upper and lower pulleys 2, 3. The lower pulley is driven by an electric motor 4 rockably secured to a base-plate 6. The upper roller 2 is mounted on an axle 17, Fig. 4, received in bearings 18 and slidable longitudinally of the belt in slots 16. The bearings are supported on tubes 19 connected at their lower ends to a transverse beam 20 urged upwardly by a roller 26 on a lever 25 which is itself acted on by a lever 22 having a weight 23, the action of the weight being varied by a screw 24. A spring 28 acts on a collar 27 on the tube to also support the upper roller. The inclined position of the axle 17 can be adjusted by a rod 30 disposed within the tube and, at one end, abutting the bearing 18, and, at the other end, a cap 31 screwed on to the tube. The base-plate 6, Fig. 2, is adjustable to vary the spacing between the belts. Each belt passes over a pressure beam 10, Fig. 3, which may be convex and carries lateral guides extending over the edges of the belt, the parts of the belt passing under the guides being without abrasive. The beam is urged outwardly by springs 14 acting on links 13. In other embodiments, the pressure beam 10 has a tensioned support belt 40, Fig. 11, stretched over a rod 41 which extends diagonally across the beam and is supported at its ends in bearings. A flat 42 is formed on the rod and, when the flat engages the beam, the support belt 40 has minimum convexity whereas, when it is rotated away from the beam, the amount of convexity is varied. The space between the support belt and beam may be filled with a rubber layer and felt. In another arrangement of pressure beam, the rod extends parallel to the belt for its upper part and obliquely to the belt for its lower part. In a further arrangement of pressure beam, the space 50, Fig. 13, between the support belts 40 and pressure beams 10 are filled with felt or the like which effects a flattening of the support belts, the arrangement being such that the space 52 between the abrasive belts 7 is wedge-shaped to receive the workpieces moving in the direction of the arrow 34. The machine may have one of the belts 7 mounted on a carriage having four cylinders 53, Fig. 8, movable along rails 54 provided with slots 61, 62. Each cylinder has a piston 58 which is urged upwardly by a spring 57 to press the head 60 of a bolt 59 connected to the piston against a plate secured to the rail to clamp the carriage in position. Hydraulic fluid supplied to the cylinders moves the pistons against the springs to release the carriage for adjustment of the spacing between the belts. In another embodiment, the upper roller 2 of each belt is mounted on an axle 69, Figs. 14 and 15, which is carried at the end of a lever 63 mounted on a pivot 65 and urged to tension the belt by a weight 70 on a lever 71 pivoted at 72 and connected by a link 74 to the lever 63. The pivot 65 for the lever 63 is mounted in a block 64 which is connected by a rod 68 to a screwthreaded spindle 67 for adjustment about a pivot 66. The machine may have a lateral guide element 75, Fig. 7, for the workpieces having a diagonal slot engaged by guide bolts 82 on a base 76 so as to be movable laterally upon longitudinal movement by a spindle 77. The movement of the element is also transmitted to a similar element 79 by an angled lever 80.