GB907976A - Improvements in or relating to abrasive machines - Google Patents

Abstract

907,976. Grinding. PENDERGAST, R. F. July 20, 1959 [Dec. 15, 1958], No. 24859/59. Class 60. An abrasive machine includes a frame structure, means on the frame structure for supporting and feeding a workpiece in a given direction, a first contact roll mounted in the frame structure in spaced relation to the workpiece supporting and feeding means for rotation on an axis extending generally transversely of the direction of movement of the workpiece, a second contact roll mounted in the frame structure in rearwardly spaced relation to the first contact roll for rotation on an axis parallel to the axis of the first contact roll, an endless abrasive belt entrained over the contact rolls and adaptedto engage a surface of the workpiece, means for imparting movement to the feeding means to feed the workpiece in a direction from the first contact roll toward the second contact roll and means for imparting rotation to the contact rolls, the outer cylindrical surface of the first contact roll having circumferentially spaced radially outwardly opening grooves extending helically there around. A workpiece 10, e.g. of wood or metal, is supported by rollers 6, 7, is fed through the machine by a driven roller 11 and is operated on by an endless abrasive belt 67 trained round a driven first contact roll 48, a second contact roll 54, and an idler roll 66. The first contact roll 48 has a resilient cover 49 provided with helical grooves 51 and the second contact roll 54 has a resilient cover 56 provided with helical grooves 58. The grooves 51 are wider than, and have a greater lead angle than the grooves 58. The load angle of the grooves 51 may be 45 degrees and that of the grooves 58 may be 25 degrees. Coarse grinding is thus effected at the first contact roll 48 and fine grinding at the second contact roll 54. The second contact roll 54 may be without grooves. In other respects the machine is constructed as in Specification 896,170.