Patent ID: 7673839

Claim:
A parallel four-bar mechanism comprising a first bar, a second bar, a third bar and a fourth bar, the second and third bars being parallel to each other and having their opposite ends hinged to the first and fourth bars respectively, the second bar having a first surface facing towards the third bar, and the third bar having a second surface facing towards the second bar, wherein a stopping block is mounted on the first surface, the stopping block has a stopping slot, a movable stopping pin is mounted on the second surface, the stopping pin and the stopping slot are configured to be engageable with each other, the stopping slot is provided in the movement path of the stopping pin, the stopping pin can be located in a locking position engaged in the stopping slot and an unlocking position disengaged from the stopping slot, thereby the stopping pin is movable between the locking position and the unlocking position, and the stopping pin is driven by an actuating member provided on the third bar.