| 摘要 |
977,581. Ratchet mechanism; variable-ratio gearing. B. S. OLSSON. Nov. 12, 1962 [Nov. 14, 1961], No. 42591/62. Headings F2D and F2Q. A device for performing stepwise rotational movements of selectable length and torque and including a toothed wheel 3 adapted to be driven in opposite directions by two pawls acted upon by a reciprocating member 23 of a driving mechanism 22 working with a constant stroke is characterized in that the pawls and the reciprocating member 23 are adjustable relative to each other in a transverse direction for selecting direction of rotation by action of the reciprocating member 23 on one or the other of the pawls and at a selectable point on the respective pawl for controlling the length of the feeding movement. The pawls are mounted on arms 6, 7 secured to a ring-shaped supporting member 5 carrying a lug 27 to which is hinged a piston rod of a control piston and cylinder 29 by means of which the appropriate pawl is moved into its operative position. The pawls comprise bell-crank portions 8, 9 mounted on the arms 6, 7 by pivots 10, 11 and wheelengaging portions 12, 13 pivotally mounted on stud shafts 14, 15 on the bell-crank portions 8, 9. Springs 17, 16 are located between the parts 8, 12 and 9, 13, and a draw-spring 19 having its ends anchored to studs 20, 21 on the bell-cranks 8, 9 holds the pawls out of engagement with the toothed wheel 3. A hooked lever 31 is adapted to engage a stop-head 30 on the ring 5 to locate the ring 5 in a predetermined arresting position. |
