GB457284A - Improvements in and relating to clutches for power presses and the like - Google Patents

Abstract

457,284. Positive clutches. SMITH, W. J., and PRITTY, J. J., c /o Bliss Co., Pocock Street, Blackfriars Road, London. May 24, 1935, No. 15248. [Class 80 (ii)] A rocking-key clutch, for power presses &c. is controlled by a transversely-pivoted abutment 8 capable of occupying two positions, in one of which it lies in the path of an arm 7 on the key 1 and in the other of which it lies in the path of a projection 13 on a loose ring 10 formed with a substantially radial slot 11 engaging a pin 12 on the arm 7. The projection 13 is disposed somewhat in advance of the arm 7. Thus, when the abutment is moved from the first position so as to release the arm 7, the clutch engages under the action of a spring 9. If the abutment is allowed to return to the first position, disengagement at the end of one revolution will result. If, however, the abutment is held in the second position, the projection 13 will engage therewith towards the end of one revolution and disengagement of the clutch will again result. The abutment must then be allowed to return to the first position before another operation can commence. The abutment is rotated through the medium of gear teeth thereon by a rack 16 operated against a spring 20 by a cable 17 attached to a treadle. If desired, the abutment may be capable of occupying a third position in which it lies out of the path of both the arm 7 and the projection 13, so that the clutch can remain engaged indefinitely, means being provided for normally preventing movement of the abutment into this third position ; or the ring 10 may be movable out of the path of the abutment or may be removable.