GB667973A - Frictional torque regulating device - Google Patents

Abstract

667,973. Clutches; variable-speed gearing. MERCIER, R. M. May 24, 1949 [May 31, 1948; July 7, 1948; Nov. 18, 1948; Feb. 15, 1949], Nos. 13877/49, 13878/49, 13879/49 and 13880/49. Class 80 (ii). In a machine for coiling webs, sheets, threads or strips on a reel 33, Fig. 1, the reel mandrel 34 is' driven from a motor-driven shaft 42 through friction members 41, 40 and worm or helical gearing 37, 43. A pressure E, varying automatically in proportion to the radius of the coil, is applied to the end of the worm 37 by a bellcrank lever 46 carrying a weight 47 which is moved out along the lever as the coil radius increases by a roller 48 maintained against the surface of the coil by a counterweight 50, while an oppositely-acting reaction pressure D is exerted on the worm by the resisting torque, resulting in the members 40, 41 being pressed into contact by the difference between the two pressures E and O. The tension in the web being coiled is thus maintained constant, irrespective of the radius of the coil or of the coefficient of friction between the members 40, 41. By immobilising the shaft 42, the members 40, 41 act as a brake for maintaining constant tension during uncoiling of the web. Screw-operated means may be provided to adjust the lateral position of the fulcrum 44 of the lever 46 so as to vary the pressure E. The roller 48 may be separate from the weight 47 and arranged to move the latter by Bowden mechanism. In the arrangement shown in Fig. 6, the roller 48 is replaced by a pivoted cradle 73, 74, 75 carrying a light source 81 and a photo-electric cell 89, the arrangement being such that, as the light beam is intercepted by an increase in the radius of the coil, a relay 83 is operated to energise a motor 84 which causes the cradle to follow-up the increase in coil radius. An extension 76 of one arm 75 of the cradle effects movement of the weight 47 on the lever 46. In the arrangement shown in Fig. 7, the shaft 42 is driven from a motor through expanding-pulley variable-speed gearing 94, 96, 98 controlled by a lever 102 linked by a rod 104 to the weight 47, so that the slip between the friction members may be reduced.