Patent ID: 7487696

Claim:
A driving force interrupting mechanism where a driving shaft for transmitting driving force to the side of a front wheel or to the side of a rear wheel is coupled to a driving source of a vehicle, the driving shaft is configured by an input shaft and an output shaft coaxial with the input shaft, a coupling sleeve coupled to one of the input shaft and the output shaft so that the coupling sleeve can be axially moved is moved by a fork so that the coupling sleeve is also coupled to the other of the input shaft and the output shaft, and driving force is transmitted by coupling the input shaft and the output shaft via the coupling sleeve, or driving force is disconnected by uncoupling the coupling sleeve from the other of the input shaft and the output shaft, the driving force interrupting mechanism comprising: a swinging shaft rotatably attached to a housing for supporting the driving shaft so that the driving shaft can rotate; the fork being attached to the swinging shaft so that the fork can swing; and a lost motion mechanism provided on the swinging shaft, the lost motion mechanism adapted to render further rotation of the swinging shaft ineffective in swinging the fork when the swinging shaft has been rotated and the fork has been swung to a predetermined position in which the input shaft and the output shaft are coupled, wherein: the lost motion mechanism further comprises: a spring between the swinging shaft and the fork for pressing the fork on a side of the predetermined position by coupling one end to the swinging shaft and touching the other end to a face on the reverse side to the predetermined position of the fork; a stopper member attached to the swinging shaft to regulate a swing to the side of the predetermined position of the fork; and a spring between the stopper and the housing for pressing the stopper member on a reverse side to the predetermined position by touching one end of the spring to a face on the side of the predetermined position of the stopper member and by touching another end of the spring to an inner wall of the housing.