US 5,123,833 A · Fast cycle plasticator/injector unit for molding machines

Abstract

A fast cycle plasticator/injector unit for plastic molding machines having a screw type plasticating extruder for feeding thermoplastic material through a sealed fluid flow path to an accumulator which periodically feeds the thermoplastic material through a sealed fluid flow path to an injector that comprises a cylinder with an inlet and an outlet port and a powered piston valve element disposed for reciprocating axial and rotary motion within said cylinder and having a fluid flow channel along a portion of its length in cooperative structural relationship with said inlet port to provide an open fluid flow channel between the inlet port and the charge chamber of said cylinder when the piston is in a first rotational orientation and to block fluid flow from the inlet port to the cylinder when the piston is in a second rotational orientation.

Claims14

Dependent claims

A fast cycle plasticator injector unit for injection plastic molding machines comprising:

plasticating extruder means for heating and continuously outputting a flow of thermoplastic material, an accumulator comprising a variable volume accumulation chamber having an inlet passage for receiving said continuous flow of thermoplastic material from said plasticating extruder means and an output passage for periodically expelling therethrough thermoplastic material accumulated within said accumulation chamber, and an injector comprising cylinder means and piston means, said cylinder means and said piston means together forming a variable volume injection chamber having an outlet port and an inlet port, said piston means having at least one fluid flow channel along a portion of the length thereof and said piston means being disposed at least partially within said cylinder means for controlled reciprocal axis motion over a predetermined range and controlled rotational motion over a predetermined range therein, said at least one fluid flow channel being disposed in structural relationship with said inlet port to form rotary valve means for providing an open fluid flow path between said outlet passage of said accumulator and said injection chamber through said at least one channel in a first rotational orientation of said piston means and for blocking fluid flow between said outlet passage of said accumulator and said injection chamber in a second rotational orientation of said piston means.

A machine for continuous plasticating and high pressure injection molding of thermoplastic materials comprising:

a plasticator section, an accumulator section and an injector section, said plasticator section comprising an extruder having a feed screw element mounted for inplace rotational movement within a heated barrel, said extruder being operative to move thermoplastic feed material from an input thereof to an output thereof as said material is plasticated by surface contact with said heated barrel, friction and externally applied heat, said accumulator section comprising a powered plunger disposed for reciprocal axial motion over a predetermined range within a cylinder from one end of said cylinder to form a chamber of variable volume within said cylinder, said cylinder having an outlet passage from said chamber opposite said plunger and an inlet passage adjacent said plunger, said plunger having a channel over a portion of its length positioned to provide a material flow path between said inlet passage and said chamber over the entire predetermined range of reciprocal axial motion of said plunger, said input passage being connected by a sealed flow path to the output of said plasticator section, said injector section comprising a high pressure injection cylinder and a powered piston valve element disposed for rotational and reciprocal axial motion within said cylinder to form a variable volume injection chamber within said cylinder, said injection chamber having an outlet port at an end of said chamber opposite said piston and an inlet port, said piston element having at least one channel along a portion of its length in cooperative relationship with said inlet port to form a rotary valve means for providing a fluid flow path between said outlet passage of said accumulator and said injection chamber when said piston is in a first rotational orientation and for providing an effective fluid seal between said outlet passage of said accumulator and said chamber when said piston is in a second rotational orientation.

Dependencies are inferred from the claim text.

Fast cycle plasticator/injector unit for molding machines

Life of this patent

Fast cycle plasticator/injector unit for molding machines

Life of this patent

Abstract

Claims14