GB1093005A - Improvements in or relating to wood cutting machines - Google Patents

Abstract

1,093,005. Woodworking. P. A. KIRSTEN. June 14, 1965 [June 13, 1964], No. 25124/65 Heading B5L. A machine for cutting wood chips has means for automatically changing the knives 4, 5 comprising a frame 8 having receiving stations 14 for units 41 ... 46 containing knives, the frame being movable relative to a carrier 1 for units 31 ... 36 for the knives 4, 5 so that the units 31 ... 36 may be moved from the carrier to the frame and the units 41 ... 46 from the frame to the carrier by mechanical, electromagnetic, pneumatic or hydraulic means. The carrier 1 is rotatable about a shaft 2 so that the knives comprising marking knives 4 and cutting knives 5 reduce a block of wood 7 supported by a guide 6 and pressed against the carrier into chips. The units 31 ... 36 are retained in the carrier 1 by locking rods 24, Fig. 2, urged resiliently outwards. The machine has a pair of guide rails 9 for the frame 8 which has a number of recesses 14 for carrying the units 41 ... 46 having sharpened knives. When the knives in the units 31 ... 36 have become blunt, the carrier is stopped and positioned with the unit 31 adjacent a magnetic plate 35 by a locking bar 11 actuated by a cylinder 13 engaging a recess 12 in the carrier. The frame 8 is positioned in the guide rails 9 with an empty recess 14 aligned with the unit 31. A cylinder 16 is then actuated to move the magnetic plate 15 which is energized so as to hold the unit and move it from the carrier to the recess 14 in the frame, the locking rod 24 having been moved by a rod 21 of a cylinder 20 to permit the movement of the unit. The magnetic plate is then de-energized and retracted and the frame moved by a motor 22 to align the unit 41 with the empty recess in the carrier. Thereafter, the magnetic plate is again advanced by the cylinder 16 and energized to hold the unit 41, the extension of the plate carrying the unit from the frame to the carrier where it is retained by the locking rod 24 after release by the cylinder 20. The carrier is then indexed to align the next unit 32 with the magnetic plate and the process repeated until the units 41 ... 46 have replaced the units 31 ... 36, the frame being removable from the guide rails so that the knives of the latter units can be sharpened while the machine is using the other knives. In another embodiment, the knives are carried on the inner cylindrical surface of a dish-shaped carrier and the wood to be reduced to chips is thrown against the knives by a rotating cross having a direction of rotation opposite to that of the carrier. The knives are secured to knife holders and, when blunt, are replaced by a second set which are mounted on an annular frame that can be mounted on an extension of the shaft of the rotary cross. A magnet carried by the rod of a cylinder is swung into operative position about a pivot and energized to effect the changing of the knife holders.