GB1380491A - Apparatus for adjustement of a rotary knife of side trimmer shears - Google Patents

Abstract

1380491 Rotary shears USS ENGS & CONSULTANTS Inc 12 Jan 1972 [21 Jan 1971] 1490/72 Heading B3W In an edge trimming shear a rotary cutter 4, axially adjustable relative to an axially fixed rotary cutter 6, is rotatably mounted on a shaft 8 journalled in an axially movable bearing box 10 which has an adjustment rod 18 engaged by differential screw means. The screw means comprise a sleeve 30, with internal and external threads 28, 32 of the same hand but different sizes, on which is mounted a rotatable but axially fixed nut 34, the nut being frictionally connectible by set screws 42 to the sleeve which is itself rotatable by hand wheel 56. Selectively operable means for locking the nut against rotation takes the form of a pin (50), Figs. 4 and 5 (not shown), for engaging in one of six holes 52 in a flange 36, on the nut, the frictional connecting means, the sleeve-rotating means and the nut-locking means when in locking position co-operating to effect axial movement of the sleeve when the sleeve is rotated. The difference in the size of the sleeve threads causes axial movements of the box 10 and thus the cutter 4 of different lengths, the threads 28 effecting coarse movement by rotation of the sleeve coupled to the nut and the threads 32 effecting fine adjustment by rotation of the sleeve with the nut locked against rotation. The threads 28 are say, size 18, and the threads 32 are size 16. In operation, with the nut 34 frictionally connected to the sleeve, the sleeve is rotated to cause coarse adjustment of the cutter 4 until zero clearance exists between the cutters. The hand wheel 56 is rotated to align a hole 52 with the pin (50) and the pin is engaged in the hole to lock the nut against rotation. The hand wheel is then rotated to achieve zero clearance by fine adjustment, one sixteenth of an inch per rotation to the left, Fig. 2, due to the threads 32 and one eight-tenths of an inch to the right due to the threads 28, i.e. a net adjustment of 0À0069 ins. per rotation. A locking collar 74 is then clamped on the rod to abut the sleeve 30. An index dial 64 is unclamped and moved to bring the zero marking under a pointer 70. Fine adjustment movement is then reversed until the desired clearance between the cutters is achieved.