Apparatus for injecting colorant into injection molding machine

Claim 2

In a plastic processing apparatus having a cylinder, a screw within said cylinder and a hopper mounted above and communicating with said cylinder for retaining a supply in pellet form of the plastic material to be processed, the invention comprising: a liquid material dispersing means extending into said hopper at a position a short distance above said cylinder, sufficient that said screw is shielded from said dispersing means by said pellets to prevent liquid material extruded from said dispersing means from falling upon said screw; pressurizable supply means for retaining a supply of the liquid material under pressure; and means communicating with said supply means and said dispersing means for supplying a predetermined amount of said liquid material from said supply means to said dispersing means at predetermined intervals.

Claim 3

In a plastic processing apparatus having a cylinder, a screw within said cylinder and a hopper mounted above and communicating with said cylinder for retaining a supply in pellet form of the plastic material to be processed, the invention comprising: a liquid material dispersing means extending into said hopper a short distance above said cylinder, sufficient that said sCrew is shielded from said material by said pellets to prevent liquid material extruded from said dispersing means from falling upon said screw; pressurizable supply means for retaining a supply of the liquid material under pressure; and pump means communicating with said supply means and said dispersing means for supplying a predetermined amount of said liquid material to said dispersing means at predetermined intervals, said pump having a cylinder with an inlet communicating with said supply means and an outlet communicating with said dispersing means, a piston slidable in said cylinder from a first position closing said outlet to a second position closing said inlet, and means communicating the inlet end of said cylinder with said outlet for passage of liquid material therethrough during traverse of said piston from said first position to said second position.

Claim 4

In a plastic processing apparatus having a cylinder, a screw within said cylinder and a hopper mounted above and communicating with said cylinder for retaining a supply in pellet form of the plastic material to be processed, the invention comprising: a liquid material dispersing means extending into said hopper a short distance above said cylinder, sufficient that said sCrew is shielded from said material by said pellets to prevent liquid material extruded from said dispersing means from falling upon said screw; pressurizable supply means for retaining a supply of the liquid material under pressure; and pump means communicating with said supply means and said dispersing means for supplying a predetermined amount of said liquid material to said dispersing means at predetermined intervals, said pump having a cylinder with an inlet communicating with said supply means and an outlet communicating with said dispersing means, a piston slidable in said cylinder from a first position closing said outlet to a second position closing said inlet, and means communicating the inlet end of said cylinder with said outlet for passage of liquid material therethrough during traverse of said piston from said first position to said second position.

Claim 5

In a plastic processing apparatus having a cylinder, a screw within said cylinder and a hopper mounted above and communicating with said cylinder for retaining a supply in pellet form of the plastic material to be processed, the invention comprising: a liquid material dispersing means extending into said hopper at a position a short distance above said cylinder, sufficient that said screw is shielded from said dispersing means by said pellets to prevent liquid material extruded from said dispersing means from falling upon said screw; pressurizable supply means for retaining a supply of liquid material; and pump means for pumping a predetermined amount of said liquid material from said supply means to said dispersing means at predetermined intervals; said pump means having a cylinder closed at one end, an inlet in communication with said supply means adjacent to but spaced from said end and an outlet in communication with said dispersing means spaced more remotely from said one end than said inlet; a piston slidable in said cylinder from a position with one end of said piston abutting said cylinder one end in which position said piston closes said inlet to a position where said piston closes said outlet; said piston being relieved along its periphery for a predetermined distance at a location on said periphery remote from said one end thereof to communicate with said outlet during a predetermined portion of the stroke of said piston; said piston being counterbored from said one end and having an opening extending from said counterbore to said relieved peripheral portion; said relieved portion being positioned so as to commence communication with said outlet port during the movement of said piston toward said cylinder one end immediately upon passage of said piston over said inlet whereby further movement of said piston toward said cylinder one end will cause liquid material within said cylinder to be forced out of said outlet.

Claim 6

In a plastic processing apparatus having a cylinder, a screw within said cylinder and a hopper mounted above and communicating with said cylinder for retaining a supply in pellet form of the plastic material to be processed, the invention comprising: a liquid material dispersing means extending into said hopper at a position a short distance above said cylinder, sufficient that said screw is shielded from said dispersing means by said pellets to prevent liquid material extruded from said dispersing means from falling upon said screw; pressurizable supply means for retaining a supply of liquid material; and pump means for pumping a predetermined amount of said liquid material from said supply means to said dispersing means at predetermined intervals; said pump means having a cylinder closed at one end, an inlet in communication with said supply means adjacent to but spaced from said end and an outlet in communication with said dispersing means spaced more remotely from said one end than said inlet; a piston slidable in said cylinder from a position with one end of said piston abutting said cylinder one end in which position said piston closes said inlet to a position where said piston closes said outlet; said piston being relieved along its periphery for a predetermined distance at a location on said periphery remote from said one end thereof to communicate with said outlet during a predetermined portion of the stroke of said piston; said piston being counterbored from said one end and having an opening extending from said counterbore to said relieved peripheral portion; said relieved portion being positioned so as to commence communication with said outlet port during the movement of said piston toward said cylinder one end immediately upon passage of said piston over said inlet whereby further movement of said piston toward said cylinder one end will cause liquid material within said cylinder to be forced out of said outlet.

Claim 7

In a plastic injection molding apparatus having a cylinder and screw-type plunger therein for injecting the plastic material into the molds of such apparatus by the thrust of said plunger, the cylinder being refilled during rotative retraction of said plunger, and a hopper mounted above and communicating with said cylinder for retaining a supply in pellet form of the plastic material to be molded, the invention comprising: a liquid material dispersing tube extending into said hopper at a position a short distance above said cylinder, sufficient that said plunger is shielded from said tube by said pellets to prevent liquid material extruded from said tube falling upon said plunger; pressurizable supply means for retaining a supply of the liquid material under pressure; and pump means for pumping a predetermined amount of said liquid material to said tube during each retraction stroke of said plunger; said pump means having a cylinder closed at one end, an inlet adjacent to but spaced from said end and an outlet spaced more remotely from said one end than said inlet; a piston slidable in said cylinder from a position With one end of said piston abutting said cylinder one end in which position said piston closes said inlet to a position wherein said piston closes said outlet; said piston being relieved along its periphery for a perdetermined distance at a location on said periphery remote from said one end thereof to communicate with said outlet during a predetermined portion of the stroke of said piston; said piston being counterbored from said one end and having an opening extending from said counterbore to said relieved peripheral portion; said relieved portion being positioned so as to commence communication with said outlet port during the movement of said piston toward said one cylinder end immediately upon passage of said piston over said inlet whereby further movement of said piston toward said cylinder one end will cause liquid material within said cylinder to be forced out of said outlet.

Claim 8

In a plastic injection molding apparatus having a cylinder and screw-type plunger therein for injecting the plastic material into the molds of such apparatus by the thrust of said plunger, the cylinder being refilled during rotative retraction of said plunger, and a hopper mounted above and communicating with said cylinder for retaining a supply in pellet form of the plastic material to be molded, the invention comprising: a liquid material dispersing tube extending into said hopper at a position a short distance above said cylinder, sufficient that said plunger is shielded from said tube by said pellets to prevent liquid material extruded from said tube falling upon said plunger; pressurizable supply means for retaining a supply of the liquid material under pressure; and pump means for pumping a predetermined amount of said liquid material to said tube during each retraction stroke of said plunger; said pump means having a cylinder closed at one end, an inlet adjacent to but spaced from said end and an outlet spaced more remotely from said one end than said inlet; a piston slidable in said cylinder from a position With one end of said piston abutting said cylinder one end in which position said piston closes said inlet to a position wherein said piston closes said outlet; said piston being relieved along its periphery for a perdetermined distance at a location on said periphery remote from said one end thereof to communicate with said outlet during a predetermined portion of the stroke of said piston; said piston being counterbored from said one end and having an opening extending from said counterbore to said relieved peripheral portion; said relieved portion being positioned so as to commence communication with said outlet port during the movement of said piston toward said one cylinder end immediately upon passage of said piston over said inlet whereby further movement of said piston toward said cylinder one end will cause liquid material within said cylinder to be forced out of said outlet.

Claim 9

Apparatus as set forth in claim 4 wherein said pressurizable supply means comprises a sealed reservoir for said liquid material; a conduit connecting said cylinder inlet to the bottom of said reservoir; a supply of air under pressure; and means connecting said air supply to the upper portion of said reservoir whereby liquid material therein is constantly urged toward said cylinder inlet.

Claim 10

Apparatus as set forth in claim 4 including drive means for said pump piston for effecting a predetermined number of strokes thereof at predetermined intervals during said rotative retraction of said plunger.