Injection molding nozzle

An injection molding machine for processing molten material, comprising:

• a manifold disposed between a backing plate and a mold cavity, said manifold having a melt channel formed therein in fluid communication with an injection nozzle associated with the mold cavity;
• a valve stem operatively disposed in the injection nozzle, said valve stem being affixed to a movable piston to selectably open and close a gate orifice associated with said injection nozzle;
• a back-up pad disposed between said manifold and the backing plate, said back-up pad sealingly abutting a surface of the backing plate, said back-up pad being affixed to said injection nozzle adjacent said piston;
• a sealing member disposed between the injection nozzle and said back-up pad, said sealing member configured to substantially reduce the leakage of a pressurized fluid between said back-up pad and the injection nozzle.

An injection molding nozzle for communication of a hardenable material to a mold cavity, comprising:

• a piston means disposed in a cylinder housing means, said piston means operatively affixed to a proximal end of a valving means, said valving means having a distal end adjacent an orifice means to selectably start and stop the flow of hardenable material to the mold cavity;
• a manifold bushing means having a valving means guidance portion and a bushing channel means formed therein, said manifold bushing means having a proximal end adjacent said guidance portion extending into said cylinder housing means and contacting said piston means when said valving means is positioned to stop the flow of hardenable material;
• a pad means, adapted to sealingly abut a manifold and a shoulder of said manifold bushing means, said pad means being affixed to said bushing means by a retaining means,
• sealing means configured to substantially reduce the leakage of the hardenable material from around said manifold bushing means.

An injection molding nozzle disposed in an injection molding machine comprising:

• a nozzle tip affixed to a distal end of a nozzle bushing, said nozzle tip adjacent a gate orifice;
• a manifold bushing in fluid communication with said nozzle bushing and in fluid communication with a manifold passageway;
• a back-up pad affixed to said nozzle bushing;
• a movable valve stem having a first end protruding from a top end of said nozzle bushing and a second end adjacent said gate orifice;
• a piston disposed in a cylinder housing affixed to said first end of said valve stem;
• and,
• a sealing member disposed between said back-up pad and said nozzle bushing configured to substantially reduce the leakage of a pressurized fluid transmitted to move said piston.