GB1374650A - Method and apparatus for preshaping raw logs - Google Patents

Abstract

1374650 Special processes TAIHEI SEISAKUSHO KK 5 July 1972 [13 July 1971 15 July 1971] 31470/72 Heading B3T [Also in Division B5] A method of preshaping a raw log into columnar shape for economical rotary-cutting thereof, comprises the stops of detecting points at certain axial locations along each line of intersection between the log surface and longitudinal sections passing through a central axis of the log, which axis extends entirely within the log, and then cutting away the outer surface part of the log to a depth corresponding to that of the detected point along each such line which lies nearest to said central axis thereby to preshape the log into a columnar shape of substantially the same planar shape in any cross-section thereof. In apparatus described for performing the method of log 2, Fig. 14, is fed on to a log centering device 25 and its centre axis determined. Rotatable centre spindles 24 carried by a sliding carriage 23 are positioned in line with the log axis and are then urged towards each other to grip the ends of the log. The log is then transferred to a position adjacent a guide groove forming device on a bed 71. The device, Fig. 17, comprises follower rollers 74, 74a, 74b which are reciprocably supported on respective piston-rods 73, 73a, 73b of hydraulic cylinders 72, 72a, 72b so that the rollers are pressed against the surface of the log as it is rotated. A rotary cutter 79 is so arranged relative to the rollers 74; 74a; 74b that it cuts into the log a guide groove 9 the bottom surface of which is level with the portion of the log, detected by the rollers, which is nearest the log axis. If desired several groups of rollers may be provided each group controlling a cutter which forms a guide groove related to a specific section of the log length. The grooved log is then passed to a preshaping device 37, Fig. 14, where a cutter 46 is urged against the log to remove from the log all material lying outside lines parallel to the log axis and passing through tne bottom of the guide groove 9. A shown in Fig. 8 the cutter, 11, has a non-cutting portion 10 which contacts the bottom of the groove 9 whilst the cutter removes material 12. The shaped log is then passed on to a receiving bed 26, Fig. 14, before leaving the machine. The log carrying carriage may be mounted for swinging movement instead of sliding, and the guide groove forming device may include follower rollers on pivoted arm. The guide groove forming device may be combined with the preshaping device, and cutters 47, Fig. 14, may remove bark from the log before or after forming the guide groove. Limit switch detectors 14, Fig. 9, may be used instead of the follower rollers, in which case they directly control log shaping cutters 15 and the guide groove forming step is omitted. The bark removing cutters 47 Fig. 15, comprises cutter elements 47a connected via springs 56 with a shaft 57.