Crank device
OwnerJoo S. Waninventor
Life of this patent
Estimating the term…
Abstract
A crank device can produce a large torque without increasing the locus of the crank arm. The crank arm has first and second arms which are longitudinally slidably coupled together through a pinion. The second arm is formed with two sets of rack teeth on both sides of the pinion. The pinion has along its circumference a plurality of teeth which are adapted to alternately come into meshing engagement with the respective sets of rack teeth every time the crank arm makes a half turn in the same direction. Thus, the entire length of the crank arm alternately becomes maximum and minimum every time the crank arm turns by 180.degree.. By applying a driving force to the crank arm when the length of the crank arm is maximum, it is possible to produce a large torque.
Claims19
A crank mechanism comprising:
- a rotary shaft rotatable about the longitudinal axis thereof;
- a crank arm fixed to said rotary shaft so as to rotate therewith, said crank arm comprising a first arm portion having one end fixed to said rotary shaft, and a second arm portion mounted to said first arm portion so as to be slidable relative to said first arm portion;
- a rotary member rotatably mounted to said crank arm so as to be rotatable relative to said crank arm;
- transmission means for rotating said rotary member relative to said crank arm as said crank arm is turned about the longitudinal axis of said rotary shaft;
- and motion converting means integrated with said rotary member for moving said second arm portion toward said first arm portion while said rotary member is rotating a first half of one full rotation in one direction and for moving said second arm portion away from said second arm portion while said rotary member is rotating the second half of said one full rotation in said one direction, said motion converting means comprising a first motion transmitting component coupled to said rotary member, and a second motion transmitting component engaging said first motion transmitting component during the entire time said rotary member is making said one full rotation.
Dependencies are inferred from the claim text.