GB746982A - Wood chipper - Google Patents

Abstract

746,982. Rotary cutters. IMPROVED MACHINERY. Inc. Feb. 16, 1954 [Feb. 20, 1953], No 4502/54 Class 145 A wood chipper which may be. used in the manufacture of paper comprises a generally cylindrical, rotatable drum 20 having a plurality of knives 25 at its periphery, means 60 for controlling the feed of wood 10 to be chipped and having an outer curved surface of gradually decreasing radius from the centre of the drum, and guides 42, 46 for the wood. A log 10 may be fed to the chipper on a chain-conveyer 50 driven through a gear-box 56 by a chain-and-sprocket drive 58, from a drive shaft 16 for the arum 20, the shaft 16 being rotated as by a diesel or an electric motor. During the chipping operation, feed is effected by the forward component of the movement of the cutters through the log and by the conveyer. The slices cut are split into chips of uniform width by the edges 34 of a grooved member 30 secured to the leading face of each cutter by the bolts 29 for attaching the cutter and an adjacent member 60 to the drum, the bolt-head recesses in the member 60 for the bolts 29 being plugged if desired. An equation is given defining an ideal curve for the outer surface of the members 60, which need not be continuous, and also an approximation for practical use which is in the form of a cylindrical surface of smaller radius than that of the cutting edges 26, the latter surface being the closest to producing constant velocity of a follower constrained to move in a radial path. A casing with a lower wall 18 and a bed-knife 40 supports the shaft 16 in bearings in side portions 12, and chip throats 22 are provided from which the chips are discharged by centrifugal force. The logs 10 need not be fed horizontally. Cutting frequencies, blade speeds, log feeds, clearance and rake angles, and angles of cutting zone are given.