Patent ID: 7971872

Claim:
A drive joint mechanism comprising: a drive shaft; a driven shaft arranged to be coupled to the drive shaft in coaxial relation thereto; a coupling fixed on the drive shaft for integral rotation therewith, and having a plurality of pin-engaging grooves formed in a circumferential direction of the coupling and at least one pyramid-shaped pin-guiding portion formed between the adjacent pin-engaging grooves; an engagement pin provided on the driven shaft and engageable with the pin-engaging groove; a switching device switched selectively between a transmission mode where torque is transmitted to the drive shaft and a release mode where the transmission mode is released; a support member rotatably supporting the driven shaft; wherein each of the coupling and the engagement pin is fixed at a given position in an axially non-displaceable manner relative to the respective one of the drive shaft and the driven shaft; the switching device is switched to the release mode from the transmission mode in a non-coupling state where the driven shaft is not coupled to the drive shaft; the drive shaft is rotatable in the release mode; the driven shaft is rotatable in the non-coupling state while being supported by the support member; and when the engagement pin is brought into contact with the pin-guiding portion during an operation of coupling the drive shaft and the driven shaft, at least one of the drive shaft and the driven shaft is rotated by a pressing force exerted in the axial direction by the driven shaft so as to allow the engagement pin to be guided into the pin-engaging groove by the pin-guiding portion.