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US 6,183,239 B2Granted
Injection molding machine valve gate nozzle
AssigneeFast Heat, Inc.
InventorEduardo L. Belous
Life of this patent
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AssigneeFast Heat, Inc.
InventorEduardo L. Belous
Estimating the term…
An injection molding machine valve gate nozzle having a rack driven valve pin actuator for moving the valve pin between open and closed positions during each holding cycle of operation. The valve pin actuator is sealed from the fluid flow stream and the nozzle body has a valve pin guide which substantially separates the melt stream from the valve pin during passage through the nozzle for enhanced long-term operation. The actuator has a modular construction which lends itself to economical manufacture and efficient use in multiple drop or single drop molding machines without modification.
An injection molding apparatus comprising a valve gate nozzle for heating and controlling the flow of a melt stream through a valve gate to a mold cavity, said nozzle having a nozzle body, a valve pin axially movable within said body between valve gate closing and opening positions, an actuator for moving said valve pin between said opening and closing positions during each molding cycle of operation, said actuator including a pinion fixed to said valve pin, a rack disposed for lateral movement transverse to said pinion, said rack being engageable with said pinion for rotating said pinion to simultaneously axially advance and retract said pinion and valve pin relative to said rack in response to reciprocating lateral movement of said rack, and a drive for laterally reciprocating said rack during each molding cycle of operation.
An injection molding apparatus comprising a manifold plate, a cavity plate defining a plurality of mold cavities, each mold cavity having a respective valve gate nozzle for heating and controlling the flow of a melt stream through said valve gate to a respective cavity, each said nozzle having a nozzle body, a valve pin axially movable within the body of each nozzle between valve gate closing and opening positions, said nozzles each having an actuator for moving the respective valve pin between said opening and closing positions, said actuators each including a pinion fixed to a respective valve pin, a single rack engaging the pinion of each actuator and being disposed for lateral movement transverse to said pinions for simultaneously rotating said pinions to axially advance and retract the pinions and valve pins for each of said nozzles relative to said rack in response to reciprocal lateral movement of said rack, and a drive for laterally reciprocating said rack.
An injection molding apparatus comprising a valve gate nozzle for heating and controlling the flow of a melt stream through a valve gate to a mold cavity, said nozzle having a nozzle body, a valve pin axially movable within said body between valve gate closing and opening positions, an actuator for moving said valve pin between said opening and closing positions, a valve guide disposed within said nozzle body and extending substantially the length thereof, said valve guide having an axial bore within which said valve pin is disposed for relative reciprocating movement, and said valve guide defining at least one passage extending substantially the length thereof for communicating a melt stream substantially the length of said nozzle body while separated from said valve pin and for directing the melt stream to said valve gate and into first contact with said valve pin at a location adjacent the terminal end of said valve pin.
An injection molding apparatus comprising a valve gate nozzle for heating and controlling the flow of a melt stream through a valve gate to a mold cavity, said nozzle having a nozzle body, a valve pin axially movable within said body between valve gate closing and opening positions, an actuator for moving said valve pin between said opening and closing positions, said actuator including a first laterally movable actuator member and a second rotatable actuator member, said valve pin being fixed to said second actuator member for rotation with said second actuator member, said second actuator member and pin being simultaneously rotatable in response to lateral movement of said first actuator member for axially advancing and retracting said valve pin between valve closing and opening positions, a drive for laterally reciprocating said first actuator member, and said first and second actuating members being designed to effect a ratio of lateral first actuator movement versus axial valve pin movement of at least two.
An injection molding apparatus comprising a valve gate nozzle for heating and controlling the flow of a melt stream through a valve gate to a mold cavity, said nozzle having a nozzle body, said valve body defining a flow passage for communicating a melt stream to said valve gate, a valve pin axially movable within said body between valve gate closing and opening positions, an actuator for axially moving said valve pin between said opening and closing positions and simultaneously rotating said valve pin during each molding cycle of operation.
An injection molding apparatus comprising a valve gate nozzle for heating and controlling the flow of a melt stream through a valve gate to a mold cavity, said nozzle having a nozzle body, said nozzle body defining a flow passage for communicating a melt stream to said gate, a valve pin axially movable within said body between valve gate closing and opening positions, an actuator for moving said valve pin between said opening and closing positions, said actuator having a housing, a manifold plate enclosing an upper end of said actuator housing and formed with a flow passage, a flow tube extending through said actuator housing with its opposite ends in fixed sealed relation to said manifold plate and said actuator housing respectively for communicating a melt stream between said manifold plate passage and said nozzle body passage while permitting relative temperature induced contraction and expansion between said manifold plate and actuator housing.
An injection molding apparatus comprising a valve gate nozzle for heating and controlling the flow of a melt stream through a valve gate to a mold cavity, said nozzle having a nozzle body, a valve pin axially movable within said body between valve gate closing and opening positions, an actuator for moving said valve pin between said opening and closing positions during each molding cycle of operation, said actuator including a pinion on said valve pin, an axially retained nut within which said pinion is disposed for threaded advancement and retraction relative to said nut during each molding cycle of operation, a rack disposed for lateral movement transverse to said pinion for rotating said pinion to axially advance and retract said pinion and valve pin relative to said nut in response to reciprocating lateral movement of said rack, a drive for laterally reciprocating said rack during each molding cycle of operation, said pinion having straight externally formed gear teeth oriented parallel to said valve pin on a first section of the pinion for engagement with gear teeth of said rack, and said pinion having a second externally threaded section threadedly engaging said nut.
An injection molding apparatus comprising a valve gate nozzle for heating and controlling the flow of a melt stream through a valve gate to a mold cavity, said nozzle having a nozzle body, a valve pin axially movable within said body between valve gate closing and opening positions, an actuator for moving said valve pin between said opening and closing positions during each molding cycle of operation, said actuator including a pinion on said valve pin, a rack disposed for lateral movement transverse to said pinion for rotating said pinion to axially advance and retract said pinion and valve pin in response to reciprocate lateral movement of said rack, a drive for laterally reciprocating said rack during each molding cycle of operation, said actuator having a housing mounted on an upper end of said nozzle within which said pinion is disposed, said nozzle body defining a melt stream flow passage communicating with said gate, a flow tube extending through said actuator housing for communicating a melt stream to said nozzle flow passage, a manifold plate formed with a melt stream passage for communicating a melt stream to said flow tube, and said flow tube having an upstream end secured in sealed relation to said manifold plate and a downstream end secured in sealed relation to said actuator housing.
An injection molding apparatus comprising a valve gate nozzle for heating and controlling the flow of a melt stream through a valve gate to a mold cavity, said nozzle having a nozzle body, a valve pin axially movable within said body between valve gate closing and opening positions, an actuator for moving said valve pin between said opening and closing positions during each molding cycle of operation, said actuator including a pinion on said valve pin, a rack disposed for lateral movement transverse to said pinion for rotating said pinion to axially advance and retract said pinion and valve pin in response to reciprocate lateral movement of said rack, a drive for laterally reciprocating said rack during each molding cycle of operation, said actuator having a housing mounted on an upper end of said nozzle within which said piston is disposed, said nozzle body defining a melt stream flow passage communicating with said gate, a flow tube extending through said actuator housing for communicating a melt stream to said nozzle passage, said actuator housing being formed with a bore extending through the housing within which said flow tube is mounted, and said bore having an upwardly and outwardly tapered configuration which defines a progressively larger clearance space about said flow tube in an upward direction for permitting lateral movement of said flow tube within said actuator housing bore as an incident to temperature expansion and contraction of said manifold plate.
An injection molding apparatus comprising a valve gate nozzle for heating and controlling the flow of a melt stream through a valve gate to a mold cavity, said nozzle having a nozzle body, a valve pin axially movable within said body between valve gate closing and opening positions, an actuator for moving said valve pin between said opening and closing positions during each molding cycle of operation, said actuator including a pinion on said valve pin, a rack disposed for lateral movement transverse to said pinion for rotating said pinion to axially advance and retract said pinion and valve pin in response to reciprocate lateral movement of said rack, a drive for laterally reciprocating said rack during each molding cycle of operation, said actuator having a cylindrical housing mounted on an upper end of said nozzle within which said piston is axially disposed, a removable end cap enclosing an upper end of said housing, said nozzle body defining a melt stream flow passage communicating with said gate, a flow tube extending through said actuator housing for communicating a melt stream to said nozzle flow passage, and said housing end cap having a flow passage for communicating a melt stream to said flow tube.
An injection molding apparatus comprising a valve gate nozzle for heating and controlling the flow of a melt stream through a valve gate to a mold cavity, said nozzle having a nozzle body, a valve pin axially movable within said body between valve gate closing and opening positions, an actuator for moving said valve pin between said opening and closing positions during each molding cycle of operation, said actuator including a pinion on said valve pin, said actuator including a housing within which said pinion is disposed, a nut within which said pinion is mounted for threaded advancement and retraction relative to said nut during each molding cycle of operation, said nut having an outwardly extending flange, said actuator housing having an internal annular channel for receiving said flange and longitudinally retaining said nut while permitting relative rotational movement, a rack disposed for lateral movement transverse to said pinion for rotating said pinion to axially advance and retract said pinion and valve pin relative to said unit in response to reciprocate lateral movement of said rack, and a drive for laterally reciprocating said rack during each molding cycle of operation.
An injection molding apparatus comprising a manifold plate, a cavity plate defining a plurality of mold cavities, each mold cavity having a respective valve gate nozzle for heating and controlling the flow of a melt stream through said valve gate to a respective cavity, each said nozzle having a nozzle body, a valve pin axially movable within the body of each nozzle between valve gate closing and opening positions, said nozzles each having an actuator for moving the respective valve pin between said opening and closing positions, said actuators each having a housing supported under the manifold plate with the manifold plate enclosing an upper end of the housing, said actuators each including a pinion on each valve pin, a rack disposed for lateral movement transverse to said pinions for simultaneously rotating said pinions to axially advance and retract the pinions and valve pins for each of said nozzles in response to reciprocal lateral movement of said rack, and a drive for laterally reciprocating said rack.
An injection molding apparatus comprising a manifold plate, a cavity plate defining a plurality of mold cavities, each mold cavity having a respective valve gate nozzle for heating and controlling the flow of a melt stream through said valve gate to a respective cavity, each said nozzle having a nozzle body, a valve pin axially movable within the body of each nozzle between valve gate closing and opening positions, said nozzles each having an actuator for moving the respective valve pin between said opening and closing positions, said actuators each including a pinion on each valve pin, a rack disposed for lateral movement transverse to said pinions for simultaneously rotating said pinions to axially advance and retract the pinions and valve pins for each of said nozzles in response to reciprocal lateral movement of said rack, a drive for laterally reciprocating said rack, said nozzles each defining a melt stream flow passage communicating with a respective gate, a flow tube extending through the actuator of each nozzle for communicating a melt stream to the nozzle flow passage, and said manifold plate being formed with flow passages communicating a melt stream to the flow tubes of each nozzle actuator.
An single drop injection molding apparatus comprising a valve gate nozzle for heating and controlling the flow of a melt stream through a valve gate to a mold cavity, said nozzle having a nozzle body that defines a passage for communicating a melt stream through said nozzle to said gate, a valve pin axially movable within said body between valve gate closing and opening positions, an actuator for moving said valve pin between said opening and closing positions, said actuator including a housing mounted on an upper end of said nozzle and a pinion within said housing, said valve pin being mounted in depending relation to said pinion, said valve pin actuator having an end cap enclosing an upper end of said actuator and being formed with a passage for enabling communication of a melt stream to said nozzle body passage, said end cap passage having an inlet configured to receive an injection supply nozzle operable for directing a melt stream from a source to said end cap passage, a rack disposed for lateral movement for rotating said pinion to axially advance and retract said pinion and valve pin in response to reciprocating lateral movement of said rack, and a drive for laterally reciprocating said rack.
An single drop injection molding apparatus comprising a valve gate nozzle for heating and controlling the flow of a melt stream through a valve gate to a mold cavity, said nozzle having a nozzle body that defines a passage for communicating a melt stream through said nozzle to said gate, a valve pin axially movable within said body between valve gate closing and opening positions, an actuator for moving said valve pin between said opening and closing positions, said actuator including a housing mounted on an upper end of said nozzle and a pinion within said housing, said valve pin being mounted in depending relation to said pinion, said valve pin actuator having an end cap enclosing an upper end of said actuator and being formed with a passage for enabling communication of a melt stream to said nozzle body passage, a flow tube extending through said actuator housing for communicating a melt stream between said end cap passage and said nozzle body passage, said flow tube being disposed within an upwardly tapered bore of said actuator housing which permits relative movement of the flow tube as an incident to temperature contraction and expansion of said actuator, end cap and nozzle body, a rack disposed for lateral movement for rotating said pinion to axially advance and retract said pinion and valve pin in response to reciprocating lateral movement of said rack, and a drive for laterally reciprocating said rack.
An injection molding apparatus comprising a valve gate nozzle for heating and controlling the flow of a melt stream through a valve gate to a mold cavity, said nozzle having a nozzle body, a valve pin axially movable within said body between valve gate closing and opening positions, an actuator for moving said valve pin between said opening and closing positions during each molding cycle of operation, said actuator including a pinion fixed to said valve pin, a rack disposed for lateral movement transverse to said pinion for simultaneously rotating said pinion and the pin fixed thereto to axially advance and retract said pinion and valve pin relative to said rack in response to reciprocating lateral movement of said rack, and a drive for laterally reciprocating said rack during each molding cycle of operation.
An injection molding apparatus comprising a valve gate nozzle for heating and controlling the flow of a melt stream through a valve gate to a mold cavity, said nozzle having a nozzle body, a valve pin axially movable within said body between valve gate closing and opening positions, an actuator for moving said valve pin between said opening and closing positions during each molding cycle of operation, said actuator including a pinion on said valve pin, an elongated selectively movable actuating member extending laterally from said pinion for rotating said pinion to axially advance and retract said pinion and valve pin in response to actuating movement of said member, a drive for moving said actuating member during each molding cycle of operation, and said pinion having a first externally disposed operative section cooperating with said actuating member for imparting rotational movement to said pinion in response to movement of said actuating member and a second externally disposed operative section cooperating with an axially fixed element of said actuator for axially advancing and retracting said pinion and valve pin in response to rotational movement of said pinion.
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
No related US applications are recorded in the indexed filing history.
Gates: gate inserts
Moulds: sprue channels ; Runner channels or runner nozzles
Consisting of needle valve systems: drive means therefor
Heating or cooling means therefor: thermocouples or heat sensors
Term ended 20 Jan 2019 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention relates generally to an injection molding apparatus, and more particularly, to an injection molding machine valve gate nozzle having a reciprocal valve pin cyclically movable between valve gate opening and closed positions for controlling the flow of fluid material to a mold cavity.
Nozzles commonly are employed in plastic injection molding machines for heating and directing the flow stream, such as molten plastic, through a gate into a mold cavity while maintaining the flow stream at the proper elevated temperature. Nozzles, sometimes referred to as valve gate nozzles, are known which each include a valve pin movable by an actuator for opening and closing the valve gate at the nozzle tip during each cycle of the molding operation Such valve gate nozzles may be employed in single cavity molds, or alternatively, a series of nozzles may be used in multiple cavity molds. The valve pin actuating means for such valve gate nozzles heretofore have been relatively complicated in design and problem prone in operation. They also often are mechanically inefficient and do not permit precision control of valve pin movement.
Since the plastic injection mold apparatus typically is operated at temperatures in the range of 500-700° F., the valve pin actuator cannot contain lubricant, which may leak and contaminate the flow stream. As a result, relative movement of the actuator parts causes wear and erosion over time, which can effect the shut-off position of the valve pin. Periodically it is necessary to recalibrate the position of the valve pin and/or replace the valve pin and actuator, which may require substantial disassembly of the mold apparatus.
FIG. 1 is a vertical section of a multiple cavity injection molding apparatus having a plurality of valve gate nozzles in accordance with the present invention;
FIG. 2 is an enlarged fragmentary section of a valve pin actuator for one of the nozzles, taken in the plane of line 2—2 in FIG. 1;
FIGS. 3 and 4 are enlarged vertical sections of the valve gate nozzle, taken in the plane of lines 3—3 and 4—4 in FIG. 2, respectively;
Referring more particularly to FIG. 1 of the drawings, there is shown an illustrative multiple-cavity injection molding machine 10 comprising a conventional mold cavity plate 11 defining a plurality of mold cavities 12, a gate plate 14, disposed immediately above the mold cavity plate 11, a manifold plate 15, an uppermost retainer plate 16, and spacer plates 18, 19, 20. A plurality of valve gate nozzles 25, corresponding to a number of the mold cavities 12, are mounted in the gate and spacer plates 14, 20. The manifold plate 15 has a single entry bushing 26 which receives a machine nozzle 27 for directing a melt stream, such as a fluid plastic material from a supply source, into a central passage 28 that communicates material to branch passages 29 each leading to a respective one of the valve gate nozzles 25, which heat the respective flow streams and sequentially control the flow thereof to the mold cavities 12. For heating the manifold 15 and the liquid flow stream directed through the passageways 28, 29, the manifold 15 has a plurality of electric manifold heaters 30. It will be appreciated that since the valve gate nozzles 25 are identical in construction only one need be described herein in detail.
Each valve gate nozzle 25 comprises a cylindrical body 31 having an axial bore 32. The axial bore 32 extends longitudinally through a central cylindrical core 34 of the nozzle body 31 for enabling direction of the fluid flow stream to a valve gate 35. A feed tube 36 in this case communicates between each manifold passage 29 and a fluid passage 37 formed in an upstream end of the nozzle body 31. The gate 35 of the mold apparatus in this instance is defined by a generally cylindrical gate insert 38 threaded into a downstream end of the cylindrical core 34. The gate insert 38 has an internal spherical dome chamber 39 leading to the gate 35, which in turn communicates with the mold cavity 12 (FIG. 3). The gate insert 38 has an outwardly extending flange 40 intermediate its ends for engaging a downstream end of the core 34 for establishing the predetermined axial position of the gate 35 with respect to the nozzle body 31. The illustrated gate insert 38 has a flat downstream end co-planar with the bottom of the gate plate 11.
For heating the melt stream during its travel through the axial nozzle 25, the nozzle body 31 includes an electrical resistance heating element 42 helically wound around the cylindrical core 34, which preferably is made of ceramic. The core 34 and electrical heating element 42 are disposed within a cylindrical bore of an outer shell 44, preferably made of metal, with an electrically insulative powder 45, such as magnesium oxide, interposed between the core 34 and metallic shell 44 in surrounding relation about the heating element 42. To compress the powder 45 and fill all voids around the heating element 42 for efficient thermal conductivity and for securing the shell 44, heating element 42, powder 45, and core 34 in an integral unit, the shell 44 preferably is swedged by rolling or the like to compress and reduce its diameter.