GB614924A - Improvements in and relating to clutch mechanism - Google Patents

Abstract

614,924. Clutches. TRIGGS, W. W. (Koehring Co.). Dec. 11, 1945, No. 33450. [Class 80 (ii)] A clutch, particularly for heavy duty work such as for power cranes or shovels, comprises a spider 4 secured to a driving shaft 2 and carrying a friction band 5 for engagement with a drum 1 forming the driven member of the clutch. One end of the band 5 is anchored at 6 to the spider 4 whilst the other end 7 is adapted to be actuated through a lever 8 and a toggle linkage 9, 9 by relative rotation of a ring 13, on the tub 4a of the spider 4, which is connected by a link 16 with an arm 12a on one of the toggle links 9. This relative rotation is effected by the engagement of a brake band 23 with the ring 13, to bring the clutch into operation, by a manually-operated lever 17, Fig. 1A, and links and levers 18, 19, 20. The manual effort on lever 17 is supplemented by power from the driving shaft 2 by arranging the ring 13 to be normally driven at the same speed as the spider 4 by a countershaft 37 having gears 33, 38 meshing with gears 30 and 40 on the shaft 2 and ring 13 respectively. The gear 33 is fixed, but the gear 38 is carried in a frame 42 adapted for a small amount of transverse movement allowed by links 43, 44 and universal connections of the shaft 37 with its gears 33, 38. Thus, when the brake band 23 is manually applied, the ring 13 is retarded and the gear 38 with its frame 42 moves transversely to the clutch axis and through a screw 48 on a lug 45 of the link 44 acts on an extension 29 of the lever 20 to increase the pressure on the brake 23 and so increase the clutch engaging effort. A certain amount of lost motion is provided between the extension 29 of lever 20 and the link 44 so that initial free movement of the lever 20 on applying the band 23 is allowed. This lost motion may be taken up by the screw 48 when a purely manual application of the clutch is required without the supplementary action of the gearing and frame 42.