부산대학교 도서관

An apparatus includes a frame, a rotatable first shaft, wherein the first shaft includes a first cam, a rotatable second shaft, an item gripper connected to the second shaft by a connection including a link and an offset shaft rotatably connected to the link, and a linkage. The link is adapted to rotate with the second shaft for pivoting the offset shaft about the second shaft. The item gripper includes jaws adapted to open and close when the offset shaft is axially rotated relative to the link. The linkage connects the first cam on the first shaft to a rider on the offset shaft. The linkage includes a second having a stepped surface for a stepped movement of the rider along the stepped surface to open the jaws during a predetermined angular movement of the offset shaft about the center axis of the second shaft.