抄録
A conical headed punch is forced through the hole in sheet metal to form lip flanges, which is subsequently used for eyelet tab staking of the lap joints. The object of the present investigation is to provide reasonable answers to the crushing strength of the lap joint. The summary of the result is ; (1) Crushing invariable occurs at the blanked-part of the sheet during stretching of the joints. But, in this state, work hardening at the compressed region is affected by dimension and size of something. (2) Lip flanges restrained in the change of the internal shape of eyelets under the staking operation, and subsequently, the strength of the joint is increased considerably. (3) From the viewpoint of joint efficiency, it is seen that it cannot endure great loads nor great stressed.
