PURPOSE: To achieve a reduction in the breakage of a back lid of a watch case, by visually recognizing a notch of the back lid with a photo sensor for positioning at a specified point to be connected to the watch case.
CONSTITUTION: A back lid with an O ring 8 for waterproofing thereon is fixed at a specified position of a rotary pedestal 1 with the absorption of a vacuum nozzle 1a and rotated with the pedestal 1. Then, the notch not illustrated of the back lid turning is visually recognized with a photo sensor 3 and the turning thereof is stopped at a specified angle position. Then, a watch case 5 containing a module 9 sucked securely at the tip of a conveying arm 4 is transported above the back lid and so set that a bite 5a of the watch case 5 is not deviated in the position plane-wise from that 2c of the back lid. Thereafter, one of the arm 4 or the pedestal 1 or both thereof are lifted or lowered to connect the bites of the case 5 and the back lid. This always enables the mounting of the back lid on the case 5 in normal condition, thereby reducing breakage of the case 5 or the back lid.
HOSHINO MASAO