GB265584A - Improvements in and relating to winding drum actuating and controlling mechanism - Google Patents

Abstract

265,584. Shepard, F. J., and Warshaw, N. Feb. 8, 1926, [Convention date]. Actuated or applied by springs; band. - In stacking machines a friction clutch braking device permits free rotation of the driving shaft during winding but prevents running down of the load if winding is stopped. During lowering the brake is applied automatically if the attendant ceases to exert pressure on the brake-releasing mechanism. The driving shaft 28, Fig. 3, is formed with a slightly enlarged grooved section 31, which may be milled, but preferably is swaged, to provide teeth 32 which engage a gear 34 on the winding drum shaft 35. A brake drum 44 is rotatably mounted on the shaft 28 and is engaged externally by brake bands 45, 46 and internally by clutch shoes 51, 52, 53. The clutch shoes are pivoted together and the adjacent ends of the shoes 51, 53 are pivoted to the links 56, 57 of a toggle, the pivotal joint 58 of which is connected by a link 59 to arms 61 secured to the shaft 28. When the shaft 28 is rotated to wind the cable on the drum 38, the arms 61, Fig. 2, are moved clockwise and the joint 58 is moved sufficiently to withdraw the shoes from engagement with the drum. Disengagement is maintained by the engagement of a lug 63x on the shoe 52 with a pin 63 passed through the shaft 28. Brackets at the upper ends of the brake bands are slidablv mounted on a bolt 49 and kept apart by a spring 50. The lower end of the brake band 45 is pivoted to the arm 65 of a bell-crank lever, the other arm 67 of which carries a pin 68 engaging the slotted end 69 of a lever 70 secured to a shaft 71. An arm 72 on the shaft 71 is pivoted to the lower end of the brake band 46. The spheroidal end 74 of the lever 70 is slotted to receive the upper end of a vertical guide rod 76, the lower end of which is slidably mounted in a guideway in a bracket 77 on the framework. The lower face of the head 74 rests on a collar 78 which is free on the rod 76 and is engaged by a helical spring 79 which rests on a cross-head 80 fixed to the rod. A helical spring 82 is placed between the cross-head 80 and a collar 83 which rests on the bracket 77. Links 86 pivoted to the cross-head 80 are connected to arms 88 on a shaft 90. During winding the stiff spring 82 and the relatively light spring 79 act together to lift the head 74 and apply the brake bands to the drum. During lowering the shaft 90 is slightly rotated by the attendant in a counterclockwise direction, Fig. 2. This movement causes the arm 88 to depress the links 86 and cross-head 80, and the spring 82 to be compressed. The compression of the spring 82 permits the expansion of the spring 79 and this causes a decrease in the force exerted on the end of the lever 70. The brakes are therefore released gradually from the drum and rotation of the shaft 28 is permitted. The crank handle 40 used for actuating the shaft 28 is provided with an additional aperture 93, Fig. 4, to engage the end of the shaft 90. The apertures 92, 93 are made of different sizes in order that the full leverage of the crank cannot be applied to the shaft 90.