초록 ▼

A Bi-directional rack assembly that rotates one column of threaded cores and unscrews threaded closures while moving in the forward direction. The Bi-directional rack then mechanically changes position to engage an adjacent column of rotating threaded cores and at the end of a second molding cycle r

A Bi-directional rack assembly that rotates one column of threaded cores and unscrews threaded closures while moving in the forward direction. The Bi-directional rack then mechanically changes position to engage an adjacent column of rotating threaded cores and at the end of a second molding cycle rotates the threaded cores and unscrew threaded closures while moving in the reverse (reset) direction. A set of timed-advance devices are engaged by a smaller pinion gear and idler gear assemblies to the Bi-directional rack and as the Timed-Advance devices are activated, they allow pneumatic pistons to advance the stripper plate in time with the threaded closures as they are being unscrewed from the threaded cores. A second "rapid advance" pneumatic piston eliminates the need for an external rapid rise camming feature. A rotating core comprising a stock, rotating core, a stock water-seal insert and a custom core top.

대표청구항 ▼

What is claimed is: 1. A method for making plastic articles by a plastic injection molding process, the method comprising: providing means for manufacturing the plastic articles wherein articles are manufactured while a crosshead assembly and a plurality of rack assemblies move in a forward directi

What is claimed is: 1. A method for making plastic articles by a plastic injection molding process, the method comprising: providing means for manufacturing the plastic articles wherein articles are manufactured while a crosshead assembly and a plurality of rack assemblies move in a forward direction and articles are manufactured while said crosshead assembly and plurality of rack assemblies move in a reverse direction, wherein the means for manufacturing the plastic articles includes rotatable cores that rotate in the same direction regardless of the movement of the crosshead assembly and plurality of rack assemblies in the forward or reverse direction, wherein the rotatable cores are arranged in an array of adjacent columns, and wherein the plurality of rack assemblies are bi-directional rack assemblies adapted to cause the rotation of respective adjacent rotatable cores, with one rack assembly located on the outside of each of the outermost columns of rotatable cores and the remaining rack assemblies are each located in between a number of adjacent columns of rotatable cores. 2. The method according to claim 1, wherein after a molding sequence is complete and the molded plastic articles are to be unscrewed, means for relieving a clamping pressure on a tapered shutoff surface of the rotatable cores is activated, wherein a stripper plate is pushed away from a stationary plate in time with a thread pitch of the threaded articles as they are being unscrewed from a threaded portion of the cores. 3. The method according to claim 2, wherein the stripper plate is quickly raised at an accelerated speed to separate and/or eject any molded articles that may want to stick to the stripper plate using pneumatic pistons, wherein said pneumatic pistons are activated when the unscrewing of the threaded articles is complete. 4. The method according to claim 3, wherein the stripper plate is pushed away about 0.005 to 0.010 inches from the stationary plate before the bi-directional racks begin to move the rotatable cores. 5. The method according to claim 1, wherein after the molding sequence is complete and the plurality of rack assemblies have completed its motion in the respective forward or reverse direction, actuating bars which were moving in conjunction with the plurality of rack assemblies continue to move a sufficient distance so as to cause the plurality of rack assemblies to disengage from the respective rotatable cores to which each rack assembly was engaged during the completed motion and to engage the respective rotatable cores in the adjacent column of rotatable cores, except in the case of the outermost rack assemblies, for the start of a subsequent molding sequence, and wherein the outermost rack assemblies engage only those column of rotatable cores to their respective left or right depending on their placement. 6. The method according to claim 1, wherein each core comprises a lower stock portion and a separable top core portion. 7. The method according to claim 1, wherein each core comprises a lower stock portion, a separable top portion and an intermediate portion. 8. The method according to claim 6, wherein the lower stock portion includes a replaceable stock water-seal insert portion at its lower end. 9. The method according to claim 7, wherein the lower stock portion includes a replaceable stock water-seal insert portion at its lower end. 10. A method for making plastic articles by a plastic injection molding process, the method comprising: manufacturing the plastic articles while a crosshead assembly and a plurality of rack assemblies move in a forward direction and manufacturing plastic articles while said crosshead assembly and plurality of rack assemblies move in a reverse direction, wherein rotatable cores rotate in the same direction regardless of the movement of the crosshead assembly and plurality of rack assemblies in the forward or reverse direction, wherein the rotatable cores are arranged in an array of adjacent columns, and wherein the plurality of rack assemblies are bi-directional rack assemblies adapted to cause the rotation of respective adjacent rotatable cores, with one rack assembly located on the outside of each of the outermost columns of rotatable cores and the remaining rack assemblies are each located in between remaining adjacent columns of rotatable cores. 11. The method according to claim 10, wherein after a molding sequence is complete and the molded plastic articles are to be unscrewed, means for relieving a clamping pressure on a tapered shutoff surface of the rotatable cores is activated, wherein a stripper plate is pushed away from a stationary plate in time with a thread pitch of the threaded articles as they are being unscrewed from a threaded portion of the cores. 12. The method according to claim 11, wherein the stripper plate is quickly raised at an accelerated speed to separate and/or eject any molded articles that may want to stick to the stripper plate using pneumatic pistons, wherein said pneumatic pistons are activated when the unscrewing of the threaded articles is complete. 13. The method according to claim 12, wherein the stripper plate is pushed away about 0.005 to 0.010 inches from the stationary plate. 14. The method according to claim 10, wherein after the molding sequence is complete and the plurality of rack assemblies have completed its motion in the respective forward or reverse direction, actuating bars which were moving in conjunction with the plurality of rack assemblies continue to move a sufficient distance so as to cause the plurality of rack assemblies to disengage from the respective rotatable cores to which each rack assembly was engaged during the completed motion and to engage the respective rotatable cores in the adjacent column of rotatable cores for the start of a subsequent molding sequence, and wherein the outermost rack assemblies engage only those column of rotatable cores to their respective left or right depending on their placement. 15. The method according to claim 10, wherein each core comprises a lower stock portion and a separable top core portion. 16. The method according to claim 15, wherein the lower stock portion includes a replaceable stock water-seal insert portion at its lower end. 17. The method according to claim 10, wherein each core comprises a lower stock portion, a separable top portion and an intermediate portion. 18. The method according to claim 17, wherein the lower stock portion includes a replaceable stock water-seal insert portion at its lower end. 19. A rotatable core for use in an apparatus for making plastic articles by a plastic injection molding process, the rotatable core comprising: a lower stock portion and a top core portion; the rotatable core rotatable in only one direction having a longitudinal hollow passageway extending generally from a lower end of the lower stock portion to an upper end of the top core portion for the passage of cooling fluid through a bubbler sleeve inside said hollow passageway; the lower end of the lower stock portion further comprising a replaceable stock water-seal insert portion at its lower end; and the top core portion further comprising gear means at an intermediate location on its outside surface for engaging a geared rack, which causes the rotation of the rotatable core, wherein the water-seal insert portion is configured to be replaceable without disassembly of a mold used in the apparatus for making the plastic articles by the plastic injection molding process, and wherein the water-seal insert portion is threadedly attached to the rotating core so as to provide an orientation to counter rotational forces when an unscrewing motion of the rotatable core from the plastic part takes place. 20. A rotatable core for use in an apparatus for making plastic articles by a plastic injection molding process, the rotatable core comprising: a lower stock portion, an intermediate stock portion and a top core portion; the rotatable core rotatable in only one direction having a longitudinal hollow passageway extending generally from a lower end of the lower stock portion, through the intermediate stock portion to an upper end of the top core portion for the passage of cooling fluid through a bubbler sleeve inside said hollow passageway; the lower end of the lower stock portion further comprising a replaceable stock water-seal insert portion at its lower end; the intermediate stock portion further comprising gear means at an intermediate location on its outside surface for engaging a geared rack which causes the rotation of the rotatable core; and the top core portion having means for removing said top core portion from the intermediate stock portion for replacement of said top core portion, wherein the water-seal insert portion is configured to be replaceable without disassembly of a mold used in the apparatus for making the plastic articles by the plastic injection molding process, and wherein the water-seal insert portion is threadedly attached to the rotating core so as to provide an orientation to counter rotational forces when an unscrewing motion of the rotatable core from the plastic part takes place. 21. A timed advance assembly for relieving clamping pressure on a tapered shutoff surface of rotatable cores in a plastic injection molding process for making threaded articles, the timed advance assembly, in relation to each Bi-directional rack, comprising: two timed advance assemblies, each including a timed advance pneumatic piston assembly serving as means adapted for pushing a stripper plate away from a stationary plate in time with a thread pitch of the threaded articles as said threaded articles are being unscrewed from a threaded portion of rotatable cores used in the molding process; means for cooperative engagement of the two timed advance assemblies with first and second pinion gear assemblies and idler gears; the pinion gear assemblies being engageable to both the timed advance assemblies and the idler gears, the idler gears being engageable with the pinion gear assemblies, the idler gears and pinion gear assemblies being spaced so that when the first pinion gear assembly is engaged with a Bi-directional rack used in the molding process, the second pinion gear assembly is not engageable with the Bi-directional rack, wherein during a forward stroke of the Bi-directional rack, the second pinion gear assembly turns at idle, as the Bi-directional rack moves sideways to an alternate position, it disengages from the first pinion gear assembly and engages the second pinion gear assembly, and during the reverse stroke of the B i-directional rack, the first pinion gear assembly turns at idle, wherein the first timed advance piston assembly is also engageable with an upper gear of the first pinion gear assembly, wherein while the Bi-directional rack is turning the first pinion gear assembly during its forward stroke, the upper gear of the first pinion gear assembly is engageable with the timed advance assembly and rotates it, wherein a rotatable core which is externally threaded is allowed to advance within an internally threaded bushing, wherein the advancing of the externally threaded rotatable core allows a primary pneumatic piston to advance forward and push the stripper plate up in time with the unscrewing molded part, and at the same time, the idler gears rotate the second pinion gear assembly in the opposite direction, wherein the second pinion gear rotates the second timed advance assembly in the opposite direction to allow the externally threaded rotatable core to retract within the internally threaded bushing, and wherein at the end of the Bi-directional rack's forward stroke, the retracted externally threaded core is down and in position to control a second primary pneumatic piston to advance forward during the reverse stroke of the Bi-directional rack. 22. The timed advance assembly according to claim 21, further comprising: rapid advance pneumatic piston means separate from the timed advance pneumatic piston assemblies adapted for quickly raising the stripper plate at an accelerated speed to separate and/or eject any molded articles that may want to stick to the stripper plate, wherein said rapid advance pneumatic pistons are adapted to activate when the unscrewing of the threaded articles is complete. 23. The timed advance assembly according to claim 22, wherein each timed advanced piston assembly comprises a hollow piston rod, which is in sliding operative engagement with a corresponding piston of each of the rapid advance piston assemblies, which independently operates inside the hollow piston rod. 24. A Bi-directional rack assembly for use in plastic molding processes for making plastic articles, the assembly comprising: a crosshead assembly; a plurality of spaced-apart parallel Bi-directional rack assemblies engaged at one end with the crosshead assembly with retainer means for retaining said one end within the crosshead assembly; each Bi-directional rack assembly comprising an elongate longitudinal rack having pitched gear teeth on opposite sides of each rack, said gear teeth adapted for operative engagement with mating gear teeth on adjacent columns of spaced-apart rotatable cores when said rack is used in operative engagement with a mold; an upper actuating bar and a lower actuating bar in cooperative horizontal side-to-side engagement with respective upper and bottom sides of each rack; and means for retaining said actuating bars in the crosshead assembly and in cooperative alignment with the rack. 25. The assembly according to claim 24, wherein the rack and actuating bars are cooperatively engaged such that the rack has a plurality of spaced-apart parallel slots on each of its upper and bottom surfaces and each actuating bar has a plurality of spaced-apart projections adapted for sliding operative engagement within each corresponding slot on the rack. 26. The assembly according to claim 24, wherein the rack and actuating bars are cooperatively engaged such that the rack has a plurality of spaced-apart projections on each of its upper and bottom surfaces, and each actuating bar has a plurality of spaced-apart parallel slots adapted for sliding cooperative engagement with each corresponding projection on the upper and bottom surfaces of the rack. 27. The assembly according to claim 25, wherein the parallel slots are angularly oriented to accommodate and facilitate side-to-side motion in an angular forward and reverse direction of the rack and to cause the sequential engagement of the rack gear teeth with the respective adjacent columns of rotatable cores. 28. The assembly according to claim 26, wherein the parallel slots are angularly oriented to accommodate and facilitate side-to-side motion in an angular forward and reverse direction of the rack and to cause the sequential engagement of the rack gear teeth with the respective adjacent columns of rotatable cores. 29. A Bi-directional rack assembly for use in plastic molding processes for making plastic articles, the assembly comprising: an elongate longitudinal rack having pitched gear teeth on opposite sides of each rack, said gear teeth adapted for operative engagement with mating gear teeth on adjacent columns of spaced-apart rotatable cores when said assembly is used in combination with other racks assemblies when in operative engagement with a mold; an upper actuating bar and a lower actuating bar in cooperative horizontal side-to-side engagement with respective upper and bottom sides of the rack. 30. The assembly according to claim 29, wherein the rack and actuating bars are cooperatively engaged such that the rack has a plurality of spaced-apart parallel slots on each of its upper and bottom surfaces and each actuating bar has a plurality of spaced-apart projections adapted for sliding operative engagement within each corresponding slot on the rack. 31. The assembly according to claim 29, wherein the rack and actuating bars are cooperatively engaged such that the rack has a plurality of spaced-apart projections on each of its upper and bottom surfaces, and each actuating bar has a plurality of spaced-apart parallel slots adapted for sliding cooperative engagement with each corresponding projection on the upper and bottom surfaces of the rack. 32. The assembly according to claim 30, wherein the parallel slots are angularly oriented to accommodate and facilitate side-to-side motion in an angular forward and reverse direction of the rack and to cause the sequential engagement of the rack gear teeth with the respective adjacent columns of rotatable cores. 33. The assembly according to claim 31, wherein the parallel slots are angularly oriented to accommodate and facilitate side-to-side motion in an angular forward and reverse direction of the rack and to cause the sequential engagement of the rack gear teeth with the respective adjacent columns of rotatable cores. 34. A core stock water-seal insert portion for a rotatable core used in apparatus for making plastic articles by a plastic injection molding process, the stock water-seal insert portion comprising: a water-seal insert portion having means for threadedly attaching to a rotatable core portion rotatable in only one direction for use in an apparatus for making plastic articles in a plastic injection molding process and for separating from said rotatable core portion for replacing said water-seal seal insert portion when desired; the water-seal insert portion further comprising a longitudinal hollow passageway extending generally from its lower end through its upper end for the passage of cooling fluid through a bubbler sleeve inside said hollow passageway; and the lower end of the water-seal insert portion having an inlet port adapted to be in fluid communication with a fluid cooling source and the bubbler sleeve, wherein the water-seal insert portion is configured to be replaceable without disassembly of a mold used in the apparatus for making the plastic articles by the plastic injection molding process, and wherein the water-seal insert portion is threadedly attached to the rotating core so as to provide an orientation to counter rotational forces when an unscrewing motion of the rotatable core from the plastic part takes place. 35. The insert portion according to claim 34, wherein the means for attaching to and separating from the rotatable core portion comprises: a water-seal bushing adapted to threadedly engage a lower end of the rotatable core.