Abstract: A tamperproof cap assembly for a hydrant having a valve stem rod which in one embodiment is displaceable in elevation within the hydrant housing without rotation of the valve stem rod about its axis. The assembly includes a cap adapted to cover the outlet port in the hydrant housing. The cap is provided with a stem. A locking means secured to the valve stem rod engages the cap stem when the valve stem rod is in a first position and the cap stem is displaced toward the valve stem rod. The locking means releases the cap stem when the valve stem rod is displaced in elevation from the first position to a second position without rotation of the valve stem rod about its axis. The cap is provided with a pair of unthreaded facing annular walls which define an annular channel for receiving the hydrant nozzle.

Abstract: A tamperproof hydrant lock with a controlled shock absorber. Power transmitting means are mounted on an operating rod extending within a chamber in the hydrant housing. A spring is mounted between the power transmitting means and the hydrant housing. First and second hydraulic means operatively associated with the power transmitting means control gradual opening and closing of the hydrant valve over first and second delay intervals of time respectively.