Process for producing a valve-and-lid assembly

摘要

A process is described for producing a valve-and-lid assembly composed of a lid and a valve body each of which has a determined configuration and is produced separately in finished condition, the valve body from a synthetic resin of physical properties similar to those of Hytrel, with a Shore hardness of about 78 to 92 when the valve body is to be assembled with an upper body portion resting on the outer lid face about a collar of the lid; and of about 70 to 92 when the valve body is to be introduced completely into the lid collar. The valve body is then placed partially into the collar, or on the mandrel of a pressure piston, and then abruptly struck by the piston to be rammed fully into the collar and stretched so that a lower head of the valve body is moved downwardly just out of a central lid opening at an internal collar end. The mandrel is then withdrawn, permitting the valve body to contract whereby its head sealingly engages the rim about the central opening of the collar.