Patent ID: 8387477

Claim:
A gear shift device which changes speed by transmitting rotation of a shift spindle by gear shift operation input to rotation of a shift drum through an intermittent feed mechanism and a lost motion mechanism, the gear shift device comprising: an upstream rotation holding mechanism which holds in a required rotational position an upstream rotating member of the lost motion mechanism which is rotated by the gear shift operation input through the intermittent feed mechanism a latch mechanism for latching and regulating rotation of the shift drum which is located downstream of the lost motion mechanism; wherein in a downstream latch mechanism as the latch mechanism, a latch concave corresponding to each gear stage is formed on a periphery of a downstream rotating member of the lost motion mechanism and a swinging downstream latch arm latches a latch claw at its tip in the latch concave; in an upstream latch mechanism located upstream of the lost motion mechanism, a latch concave corresponding to each gear stage is formed on a periphery of the upstream rotating member of the lost motion mechanism and a swinging upstream latch arm latches a latch claw at its tip in the latch concave; and the upstream latch arm and the downstream latch arm have a swing center base end portion in common and are swingably journalled to a common latch arm shaft integrally.