METHOD FOR CLAMPING LID BODY WITH OPEN-PROOF MECHANISM

PROBLEM TO BE SOLVED: To clamp a lid body under a condition where a definite number of contrarotation-proof nails are always climbed over and are hooked by a method wherein the lid body is rotated to measure the torque and when the contrarotation-proof nail collides with the first nail and climbs over it to detect decrease in the torque, a specified amt. of rotation is performed to finish clamping. SOLUTION: When a lid body 1 is clamped, after a bottle body 6 on which the lid body 1 is placed is placed on a base by elevating an elevating mechanism of a clamping device, a helical flight 2 of the lid body 1 is hooked with a helical flight 4 of the bottle body 6 to screw the lid body 1. When the screwing advances, the contrarotation-proof nail 3 of the lid body 1 is lowered and collides with the contrarotation-proof nail 5a and when the lid body 1 is rotated furthermore, the tip nail 3a of the contrarotation-proof nail 3 of the lid body 1 climbs over the contrarotation-proof nail 5a of the bottle body 6. As a point where rotational torque is decreased when the first contrarotation-proof nail 3a of the lid body 1 climbs over the contrarotation-proof nail 5a of the bottle body 6 is detected to make it as an end point, it is possible to control accurately the number of climbing of the nail and to mechanize clamping of the lid.