Patent ID: 7204151

Claim:
A seal load inspection apparatus provided in a capping unit which performs a tightening of a metal cap fitted over a vessel, to which a rubber plug is driven, comprising a pressure block for applying a load on the rubber plug through the cap to cause it to be compressed; an air cylinder for elevating the pressure block up and down; a tightening member for folding a skirt of the cap inwardly; rotating means for rotating the tightening member relative to a table on which the vessel is placed; moving means for moving the tightening member to a position where it abuts against the cap and a position where it does not abut; load detecting means for detecting a load applied to the cap; displacement detecting means for detecting a displacement in the elevation of the top surface of the cap; air pressure control means for controlling the air pressure in the air cylinder; and load value memory means for storing a load value detected by the load detecting means; an arrangement being such that a tightening operation is performed by the tightening member by folding a skirt of the cap inwardly under a condition that the rubber plug is compressed by applying a load on the metal cap, subsequently the load is once released and then the air pressure control means is controlled to apply a load again which is gradually increased from a low value which is insufficient to cause a compression of the rubber plug to a higher value, and a load detected in the course of increasing the load at the instant when a displacement of the elevation of the top surface of the cap occurs is determined to be a seal load upon completion of the tightening operation.