GB1212239A - Rotary shear drive - Google Patents

Abstract

1,212,239. Shearing. HALLDEN MACHINE CO. 24 June, 1968, No. 29971/68. Heading B3W. A rotary shear, Fig. 2, comprises shear drums 12, 14 having shear blades 16, 15, a driving shaft 22, a driven shaft 20 and gear pairs 36 and 38 mounted on the shafts, the gear arrangement being such that backlash is taken up in the gear pairs in a manner to distribute the total gear load over both gear pairs, the total gear load including driving torque transmission to the driven shaft, locking the shear drums against clash approach of their blades and operational separation of the shear blades during cutting action. All the gears are helical. For accurate adjutment of the blades 15, 16, gear 38a is axially adjustable relative to the gear 38b by being splined at 40 to the shaft 20 and is lockable in adjusted position by means 42. The gear 38a also acts as a backlash take-up gear, being formed in two axially relatively adjustable parts 44, 46. Part 44 is directly splined to the shaft 20 at 40 and part 46 is splined at 48 to a hub 50 on part 44 and movable relative to part 44 by means of screws 52. The part 46 is adjusted until a tooth 54 on part 44 bears against the flank 60 of the nearest tooth 58 on gear 38b in one direction of rotation and a tooth 56 on part 46 bears against the flank 60 of the nearest tooth 58 in the other direction of rotation. Driving torque applied to the lefthand end of the shaft 22 is transmitted directly to the shear drum 12 and through gears 36 only to the drum 14. The gear pair 38 lock the drums against clashing approach and operational separation of the blades. In another embodiment, Fig. 8, gear backlash is taken up in either direction in an adjustable coupling 86. On relatively adjusting coupling elements 82 and 84 in the direction for backlash take-up as shown in Fig. 8, driving torque is transmitted to drum 14a through gears 36<SP>1</SP> and shaft 20a and to drum 12a via gears 36<SP>1</SP>, shaft 20a and gears 381. Gears 381 lock the drums against clashing approach of the blades and gears 36<SP>1</SP> against operational separation during cutting action. When backlash is taken up in the other direction (not shown), torque transmission is through shaft 22a to drum 12a and through shaft 22a and gears 38<SP>1</SP> to drum 14a. The other functions of the gears 36<SP>1</SP> and 38<SP>1</SP> are the same. Since only one flank of a tooth of a gear is in contact with one flank of a tooth of the other gear of a pair at any one time there is a degree of resilient torsional give in the shafts 20a, 22a. The embodiment of Fig. 8 also has a miss-out function, the shaft section 76 carrying lower drum 12a being journalled in spaced slide blocks (104), Fig. 7 (not shown), guided vertically in the shear frame (108) and pivotally connected to rods (112) eccentrically mounted on a shaft (116) which remains idle for each miss-out action. Universal drive connections 94, 96 ensure continuous drive of the lower shear drum 12a during cutting and miss-cutting.