摘要 |
A power transmission mechanism includes a cam-incorporated gear including a constant-radius cam-portion and a small-radius relief cam-portion connected via a non-constant-radius cam-portion; and first and second swingable members each including a follower which comes in contact with the constant-radius cam-portion and is positioned in an immediate vicinity of the relief cam-portion at respective first and second swing limits. The cam-incorporated gear includes two neutral positions in which one and the other of the swingable members is held at cam-axis separated and vicinity positions, respectively, wherein upon rotating the swingable members from one to the other of the neutral positions, the commencement and termination of rotation of the swingable member that moves from the cam-axis separated to vicinity positions respectively occurs at earlier and later timings. The non-constant-radius cam-portion makes a load torque greater than a surplus torque which act on the cam-incorporated gear when it rotates.
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