Shut-off valves for the nozzles of injection moulding machines

Claim 1

A nozzle device for an injection moulding machine, comprizing a nozzle portion and a valve body portion, a bore being defined in the nozzle and a throat being defined in the bore, a flow distributor being formed in the valve body portion to define therewith at least one passageway communicating with the bore, a valve member carried in the flow distributor and freely slidable axially relative thereto to open and close the throat, a transverse opening in the flow distributor, a key in the opening co-operating with the valve member, an axially slidable collar on the valve body portion co-operable with the key, a thrust assembly mounted on the valve body portion, and a fluid pressureoperable device mountable on an injection moulding machine and arranged and adapted to co-operate with the thrust assembly so that the fluid pressure device is operable to effect movement of the valve member to close the throat, and wherein the valve member has a downstream end profiled so that when moulding material is pressurized in the passageway of the valve body, a component of the pressure force acts in an axial direction with respect to the valve member to tend to move same to open the throat.