GB742141A - Improvements relating to adjustable throw cranks - Google Patents

Abstract

742,141. Adjustable-throw cranks. HORDERN, MASON & EDWARDS, Ltd. May 13, 1954 [May 13, 1953], No. 13305/53. Class 80(3) [Also in Group XXVI] An adjustable-throw crank, particularly for power presses, comprises an eccentric bush 15 rotatably mounted on a crank pin 10 to which it is locked in the adjusted position by a spring-loaded key 27 axially slidable in a keyway in the bush and engaging one of a number of locking recesses 31 in a crank cheek 12. To facilitate assembly the bush 15 is preferably split on a diametral plane and to facilitate angular adjustment is provided with a flange 23 having tommy-bar holes 24. The recesses 31 may have the same cross-section as the key, but in the construction shown the projecting portion 33 of the key has converging flats thereon to fit sector-shaped recesses 31. In the locking position the portion 33 also engages a shallow recess formed in a cam ring 36 rotatable on the crank cheek 12. When it is desired to adjust the crank throw the cam ring 36 is turned by means of holes 41, so that the inclined sides of the shallow recesses therein force the key 27 inwardly and release the lock, whereafter the bush 15 may be turned to a new selected position. The end face of the key 27 may be provided with a separate member 45 co-operating with the cam ring 36, and this member may project as shown to co-operate with a recess at the mouth of the keyway and thereby prevent rotation of the key when in the unlocked position. As an alternative to the cam ring 36, the crank cheek may have a series of radial holes registering with the recesses 31, a cam-shaped tool being inserted and turned in the appropriate hole to displace the key 27. It is stated that more than one key and keyway may be provided, or two keys may be arranged side by side in a single keyway and be adapted for alternative operation. Markings may be provided on the cam ring to indicate the adjusted value of crank throw