GB448327A - Clutches for power presses - Google Patents

Abstract

448,327. Free-wheel clutches ; operating clutches. MASCHINENFABRIK WEINGARTEN VORM. H. SCHATZ AKT.-GES., and WACHTER, A., Weingarten, Wurtemberg, Germany. Feb. 5, 1936. No. 3458. [Class 80 (ii)] A clutch for a power press comprises a floating member 16 threaded on the press shaft 14 and urged by springs 23 acting through a ball thrust ring 24 so as normally to be in frictional engagement with a driving flywheel 12 journalled on the shaft. The thread 17 is a multi-start one, each thread being of trapezoidal section, the threads being bevelled on those faces which are not engaged while the member 16 is being screwed towards the flywheel. The clutch is disengaged by moving a stop lever 33 into the path of a number of teeth 21 formed on a ring 20 secured to the member 16. The clutch may be maintained in the disengaged position by moving a pin 25 into a groove 27 in the member 16, and the shaft 14 may be bidirectionally coupled to the flywheel by inserting a pin, through a hole 30 in a collar 29 keyed to the shaft, into a hole 31 in the flywheel. The teeth 21 are so disposed that the clutch can be disengaged only during the power stroke of the press. The lever 33 is controlled so that clutch disengagement normally occurs after one revolution. The lever 33 is loosely pivoted on a pin 34 and is connected by a link 36 to an arm 37 on a spindle 38, which latter has another arm controlled by a sleeve 56, Fig. 3, through which a pedal-actuated rod 54 passes. A second spindle 39 has an arm controlled by a sleeve 58 which surrounds the sleeve 57 and which is urged upwards by a spring 57. Balls 55 carried in holes in the sleeve 56 co-operate with a groove on the rod 54 and with a groove in the sleeve 58. An arm 40 on the spindle 39 co-operates with cams 44, 45 in a ring 46 secured to a brake drum 22 keyed on the shaft 14. A brake band 50 is urged into engagement with the drum 22 by a spring 51 and is disengaged by a three-armed lever 49 pivoted on the pin 34 and controlled by a cam 47 on the spindle 38 and a cam 52 on the ring 46. With the clutch disengaged and the brake applied, as shown in Fig. 1, on depression of the pedal the rod 54 is moved upwards, carrying with it the sleeve 56, which at this time is locked to the rod 54 by the balls, The spindle 38 is thus turned anticlockwise to release the brake and to disengage the lever 33 from the teeth 21, and the clutch engages. The sleeve 58 is also moved upwards through the spring 57, so as to move the arm 40 into the path of the cams 44, 45. Towards the end of the revolution, cam 44 depresses the arm 40, and therefore the sleeve 58, sufficiently to cause the balls 55 to look the sleeve 58 to the sleeve 56 and to release the latter from the rod 54. Cam 45 then depresses arm 40 further and the spindle 38 is thus turned clockwise to move the lever 33 into the path of the teeth 21 and to release the lever 49 from control by the cam 47. The clutch therefore disengages, the point at which the brake is applied being determined bv the cam 52. The arm 40 can be slid along the spindle 39 out of the path of the cams 44, 45, so as to permit continuous working, by means of an eccentric pin 42.