Variable-ratio lever mechanisms

Claim 1

A VARIABLE-RATIO LEVER MECHANISM COMPRISING A MANUAL LEVER HAVING A FIRST, MANUALLY MOVABLE ARM AND A SECOND ARM, AN OUTPUT ACTUATOR LEVER, A FIXED PIVOT INTERMEDIATE THE ENDS OF THE OUTPUT ACTUATOR LEVER, THE OUTPUT ACTUATOR LEVER HAVING ONE END PORTION ON WHICH THE MANUAL LEVER IS PIVOTALLY MOUNTED AND ANOTHER END PORTION WHICH IS CONNECTED TO AN OUTPUT LINKAGE, THE SECOND ARM OF THE MANUAL LEVER BEING PIVOTALLY CONNECTED TO ONE END OF A RESILIENTLY YIELDABLE LINK THE OTHER END OF WHICH IS PIVOTALLY CONNECTED TO THE OUTPUT ACTUATOR LEVER AT A POINT SPACED FROM THE FIXED PIVOT, AND A LINK MEMBER PIVOTALLY CONNECTING THE MANUAL LEVER AT A POINT BETWEEN THE PIVOT FOR THE YIELDABLE LINK AND THE MOUNTING PIVOT FOR THE MANUAL LEVER TO A PAWL LEVER ONE END PORTION OF WHICH IS PIVOTALLY MOUNTED ON THE FIXED PIVOT AND THE OTHER END PORTION OF WHICH FORMS A PIVOTAL MOUNTING FOR A LOCKING PAWL WHICH IN ONE POSITION OF THE MECHANISM CAN ENGAGE A FIXED RATCHET, THE ARRANGEMENT BEING SUCH THAT IN AN INITIAL INCREMENT OF MOVEMENT OF THE MANUAL LEVER THE MECHANISM MOVES AS A WHOLE ABOUT THE FIXED PIVOT, IN A FURTHER INCREMENT OF MOVEMENT THE YIELDABLE LINK YIELDS AT A DESIGN OUTPUT LOAD AND ALLOWS THE LINK MEMBER TO MOVE THE PAWL LEVER ABOUT THE FIXED PIVOT TO BRING THE LOCKING PAWL INTO ENGAGEMENT WITH THE FIXED BAR CHAIN MECHANISM CONSTITUTED BY ONE ARM OF THE MANUAL LEVER, THE LINK MEMBER, THE PAWL LEVER AND THE OUTPUT ACTUATOR LEVER PRODUCES AN INCREASED MECHANICAL ADVANTAGE AT THE OUTPUT ACTUATOR LEVER.