A plug includes an inner pipe in which an external electric cable is installed; and an outer pipe supporting the inner pipe therein via an elastic member such that the inner pipe can move in the outer pipe in a withdrawal direction, the outer pipe being provided with a first locking portion for locking...http://www.google.com.au/patents/US5474466?utm_source=gb-gplus-sharePatent US5474466 - Electric connector having improved locking construction
