Abstract: An improved screw has a shaft having a surface and a central axis and at least one flight extending helically along the surface of the shaft in successive turns. A continuous groove is formed in the surface of the shaft and extends between successive, pushing and trailing, turns of the flight at a selected angle greater than zero. The groove defines at least one generally triangular land having a base aligned with a pushing turn of the flight and an apex between successive turns of the flight. The groove also defines another generally triangular land having a base aligned with a trailing turn of the flight. Barriers or dams may be provided on the lands and in the grooves. A second continuous groove may also be formed in the surface of the shaft.

Abstract: An improved screw has a shaft having a surface and a central axis and at least one flight extending helically along the surface of the shaft in successive turns. A continuous groove is formed in the surface of the shaft and extends between successive, pushing and trailing, turns of the flight at a selected angle greater than zero. The groove defines at least one generally triangular land having a base aligned with a pushing turn of the flight and an apex between successive turns of the flight. The groove also defines another generally triangular land having a base aligned with a trailing turn of the flight. Barriers or dams may be provided on the lands and in the grooves. A second continuous groove may also be formed in the surface of the shaft.

Abstract: A screw rotates in a containment barrel, and comprises a shaft having an upstream end and a downstream end At least one flight is secured to the surface of the shaft and extends helically in successive turns around the circumference of the shaft. An upstream barrier member extends radially from the surface of the shaft and generally transversely between successive turns of the flight. The upstream barrier is disposed proximal the upstream end of the shaft. A downstream barrier member extends radially from the surface of the shaft and generally transversely between successive turns of the flight. The downstream barrier is disposed proximal the downstream end of the shaft.

Abstract: A screw rotates in a containment barrel, and comprises a shaft having an upstream end and a downstream end At least one flight is secured to the surface of the shaft and extends helically in successive turns around the circumference of the shaft. An upstream barrier member extends radially from the surface of the shaft and generally transversely between successive turns of the flight. The upstream barrier is disposed proximal the upstream end of the shaft. A downstream barrier member extends radially from the surface of the shaft and generally transversely between successive turns of the flight. The downstream barrier is disposed proximal the downstream end of the shaft.

Abstract: A sliding ring non-return valve primarily for use with an injection molding machine utilizes a frame having cut therein one or more longitudinal grooves. Material flows around the outer edge of a flange surface, into an inlet area, and through the longitudinal grooves in the frame's outer surface before entering an accumulation volume. A ring, dimensioned to fit slidably around the frame, blocks material flow into the grooves while in an upstream position and allows material to pass through the grooves while in a downstream position. In an alternative embodiment, the non-return valve utilizes a frame that surrounds a central passage accessed by inlets. The outlet passage is located downstream of said inlet and connects the central passage with an accumulation volume. A ring is dimensioned to slidably fit around the frame. A flange surface limits the ring's upstream travel, while grooves in the flange surface throttle, or limit, material flow into the inlet area.

Abstract: An elongate projection or probe extends from the injection unit of an injection molding apparatus. A passage extends through the projection in fluid communication with the injection unit. A generally cylindrical receptacle is formed in a portion of the mold of the injection molding apparatus for receiving the projection in generally concentric sliding relation. The receptacle is in fluid communication with the mold cavity, wherein relative movement between the projection and the receptacle causes injection unit to be selectively in fluid communication with the mold.

Abstract: A sliding ring non-return valve primarily for use with an injection molding machine utilizes a frame having cut therein one or more longitudinal grooves. Material flows around the outer edge of a flange surface, into an inlet area, and through the longitudinal grooves in the frame's outer surface before entering an accumulation volume. A ring, dimensioned to fit slidably around the frame, blocks material flow into the grooves while in an upstream position and allows material to pass through the grooves while in a downstream position. In an alternative embodiment, the non-return valve utilizes a frame that surrounds a central passage accessed by inlets. The outlet passage is located downstream of said inlet and connects the central passage with an accumulation volume. A ring is dimensioned to slidably fit around the frame. A flange surface limits the ring's upstream travel, while grooves in the flange surface throttle, or limit, material flow into the inlet area.

Abstract: A sliding ring non-return valve primarily for use with an injection molding machine utilizes a frame having cut therein one or more longitudinal grooves. Material flows around the outer edge of a flange surface, into an inlet area, and through the longitudinal grooves in the frame's outer surface before entering an accumulation volume. A ring, dimensioned to fit slidably around the frame, blocks material flow into the grooves while in an upstream position and allows material to pass through the grooves while in a downstream position. In an alternative embodiment, the non-return valve utilizes a frame that surrounds a central passage accessed by inlets. The outlet passage is located downstream of said inlet and connects the central passage with an accumulation volume. A ring is dimensioned to slidably fit around the frame. A flange surface limits the ring's upstream travel, while grooves in the flange surface throttle, or limit, material flow into the inlet area.

Abstract: A non-return valve (10) primarily for use with an injection molding machine utilizes a frame (12) which surrounds a first bore (34) and a second bore (32). The second bore (32) is accessed by inlets (30). Outlet passages (40) are located downstream of said inlet (30) and connect second bore (32) with an accumulation area (6). A piston (60) is dimensioned to slidably fit within the first bore (34) and extend into the second bore (32). In a downstream position, the piston (60) allows positive flow of material from the inlet (30) to the outlet (40). In an upstream position, the piston (60) positively blocks flow of material from the inlet (30) to the outlet (40). The piston (60) can be forced to its upstream position at the beginning of the injection step or can be preclosed by eliminating rearward movement prior to injection.

Abstract: A positive-type, non-return valve (10) primarily for use with an injection molding machine utilizes a frame (12) which surrounds a first bore (34) and a second bore (32). The second bore (32) is accessed by inlets (30). Outlet passages (40) are located downstream of said inlet (30) and connect second bore (32) with an accumulation area (6). A piston (60) is dimensioned to slidably fit within the first bore (34) and extend into the second bore (32). In a downstream position, the piston (60) allows positive flow of material from the inlet (30) to the outlet (40). In an upstream position, the piston (60) positively blocks flow of material from the inlet (30) to the outlet (40). The piston (60) can be forced to its upstream position at the beginning of the injection step or can be preclosed by maintaining back pressure on the screw (2) prior to injection.

Abstract: A positive-type, non-return valve (10) primarily for use with an injection molding machine utilizes a frame (12) which surrounds a coaxial primary chamber (34). The primary chamber (34) is accessed by several passages. Inlets (30) allow material to be fed to a reduced diameter passage (34) adjacent to said primary chamber (32). Outlet passage (42) connects this reduced diameter passage (34) to outlet ports (40). A piston (60) is dimensioned to fit within said primary chamber (32) and reduced diameter passage (34). In a forward position, the piston (60) allows positive flow of material therethrough. In a rearward position, the piston (60) positively blocks flow of material from the inlet (30) to the outlet passage (42). The piston (60) is forced to its rearward position during the injection step.

Abstract: An improved apparatus for varying the pressure within a screw channel which apparatus includes a shaft having a helical flight defining a channel between consecutive turns of the flight. The screw is rotatable within a barrel. A radially movable first member is disposed at a right angle to a longitudinal axis of the screw where the plasticated material has undergone partial melting. A reciprocatively movable second member is disposed within a bore through the shaft coaxial with the axis and includes a cam slidably engaged with an inner end of the first member such that the first member can be extended into the screw channel when the second member is moved in one direction and retracted from the channel when the second member is moved in another direction. At an upstream end of the second member there is provided a rotatable thrust transmitting coupling which allows rotation of the second member relative to a male threaded portion secured to the coupling and coaxial with the second member.

Abstract: This invention relates to a method and apparatus for melting and conveying plasticated materials by independently developing an initial melt film which is necessary for proper conveying of the material. The apparatus includes a barrel having a cylindrical bore therethrough, a shaft rotatable in said bore which has a substantially circular cross-section, the shaft and bore defining a feed section, a metering section and a transition section between the feed and metering sections. The shaft is provided with a helical first channel means integral with the shaft for conveying said plasticated material in a downstream direction through the feed section, the transition section, and the metering section when the shaft is rotated.

Abstract: This invention relates to a mixing device for a feed screw for melting and conveying plasticated material of the type which rotates about a longitudinal axis in a barrel of an apparatus for melting and conveying plasticated material. The feed screw includes consecutive feed, transition, and metering sections, and further includes at least one helical main channel for conveying material in a downstream direction. The mixing device includes a cylinder having a clearance from the inside of the barrel, which cylinder rotates with the feed screw about said axis within the barrel. The outer surface of the cylinder is provided with at least one continuous mixing channel which extends over the surface of the cylinder, the channel being disposed in alternate upstream and downstream directions wherein material conveyed in the mixing channel is caused to alternately reverse its direction while proceeding through the mixing channel.

Abstract: This invention relates to apparatus for continuously varying the pressure within a screw channel of a plasticating machine by way of a variable restriction in the screw channel. The apparatus includes a cylindrical barrel, a shaft rotatable within said barrel having a substantially circular cross-section and a longitudinal axis for rotation concentric with the barrel. The shaft is provided with a helical screw channel which is defined between successive turns of at least one helical flight integrally formed with the shaft. At least one radially movable first member is disposed at a right angle to said axis within the channel at a location along the axis and is located within the channel at a location along the axis at which the material being processed is substantially melted.

Abstract: This invention is directed to an apparatus and method for melting and conveying plasticated material. The invention includes a screw conveyer which has a shaft with one or more helical flights rotating in the bore of the barrel of an extruder. At a location in the screw channel after which the melted material will be dispersed into the remaining solids bed, there is provided a groove in the shaft of the screw through which the semi-melted or agglomerated material is diverted by a protrusion which extends across the channel of the screw to the groove. The additional heat transferred to the material resulting from the enhanced distribution of melted and solid material which occurs as the semi-melted material is diverted through the groove and back into the screw channel improves the quality of the processed material.