Float stopper attaching method in liquid level sensor

摘要

A float stopper is attached to the free end of a thermoplastic switch case constituting part of a liquid level sensor by forming the free end of the switch case into a hollow, cylindrically shaped projection, fitting the float stopper over the projection through a hole formed in the stopper and, forcibly inserting a caulking tool, heated to a temperature which is lower than the melting point of the thermoplastic material constituting the switch case, into the cylindrically shaped projection to soften and spread the projection until its outer surface abuts against the rim of the hole formed in the float stopper. Upon curing the spread portion of the caulking projection holds the float stopper rigidly in place with excellent mechanical strength.