Abstract: Guardrail assembly for mounting on one side of a hospital bed having a horizontal bed frame. The assembly has a guardrail which is movable between a raised protection position and a lowered retracted position. It further has, at each end of the bed, an upward bracket; a link connected at one end to one end of the rail and pivoted adjacent the other end to the bracket so that it can move in a vertical plane, motion of both links thus causing movement of the rail between the aforesaid two positions. The assembly further provides for a pin locking mechanism on each bracket including a pin which is resiliently biassed toward the bracket and the locking end of the link for insertion in a hole of the bracket and a hole of the locking end when the guard is in the raised protection position and the holes register whereby to hold the guard in the raised position.