Tandem injection molding machine with direct feed to molds

Abstract: An injection molding machine is disclosed wherein a molding compound supply means (19, 21) having nozzle means (22) is moveable relative to a plurality of mold stations (A, B). Clamp means (24) are provided as an adjunct to the supply means or to the mold stations for effecting a compound seal at each mold station. Appropriate power means (26) are provided for accomplishing the seal.

Description: The present invention relates to an injection molding machine according to the first part of claim 1 and especially to injection molding machines having at least two molding stations arranged in tandem wherein a single movable nozzle is employed to service each molding in sequence. The FR-A 2 361 991 relates to injection molding articles from elastomeric stock materials. The apparatus comprises a plurality of separate and individually free-standing mold press units having independently controlled cure time cycles disposed in linear array, a track having spaced parallel rails extending adjacent to each of said mold press units, a carriage movable along said track, injection means supported on said carriage for movement to injection registry with a mold in any selected one of said press mold units from any other of said units. Lock means are affixed individually on each of said mold press units and locking means on said injection means that locking means being interengageable with said lock means of a selected mold press unit to resist forces tending to separate the injection means from the mold press unit during injection of said compound into the mold press unit and to isolate that forces from structures supporting the mold press unit. This apparatus shows mold press units which are not tandemly arranged. The mold press units are arranged adjacent each to the other and need a lot of room. Furthermore the carriage is separated from the mold press units and needs also a lot of room. An arrangement comparable with the above mentioned present invention is shown in the EP-A 0 326 175. There is shown a tandemly arranged injection molding machine with a central platen means supported by tierods and movable to and from a fixed platen along that rods to define a first axis and injection unit for supplying moldable material, a hot runner system operable to connect with that injection unit, power means for clamping said injection unit to said hot runner system, said hot runner system including a manifold distributor means communicating with a manifold means. The problem is the cooperation of the injection unit and the power means for clamping said injection unit to said hot runner system. For each mold inlet means one clamping means for the supply means is necessary. The EP-A 0 326 175 formes the preamble of the independent claims 1 and 15. The object of the present invention is to simplify the injection molding machine and to improve the injection of the material into said mold means. For the solution of that object according to the present invention as defined in the claims 1 and 15 the nozzle clamp means is carried by said supply means and forms a unitary assembly together with the nozzle means which is moved from mold inlet means to mold inlet means. It is the feature of the present invention to provide a source of moldable compound including a nozzle means where the nozzle is moveable, while in communication with the compound source, from station to station to introduce moldable compound into a mold located at the respective stations. A further feature of the invention is the provision of mold means having a parting line wherein the mold means includes a mold inlet means which is arranged coaxially with at least a portion of the mold parting line. A further feature of the invention is the provision of a mold inlet means which is a seamless extension of the mold means. A still further feature of the invention is the provision of means such as an extruder or like apparatus for advancing moldable material toward a molding station wherein a nozzle means is carried by supply means and the supply means and the nozzle means are moveable as a unitary assembly from station to station. A further feature of the invention is the provision of primary clamping means for clamping molds along a longitudinal axis of the molding machine and a secondary clamping means for clamping the nozzle means directly to a mold (or to a hot runner manifold servicing a mold) along an axis that is generally perpendicular to the longitudinal axis. It is a further feature of the invention wherein a secondary clamping means is provided at each molding station. A further feature of the invention is the provision of moveable platen disposed between two mold stations where the platen supports hot runner manifolds servicing molds at each station, and the platen includes secondary clamping means individual to each manifold for clamping a moveable nozzle to a manifold inlet. The language "mold inlet means" includes a seamless extension of a mold or a hot runner manifold servicing a mold. Other features and advantages of the present invention will become more apparent from an examination of the succeeding specification when read in connection with the appended drawings, in which; BRIED DESCRIPTION OF THE DRAWINGS Figure 1 is a side elevational view of a typical tandem arrangement of mold stations A and B. Figure 2 is a top plan view of the illustration of Figure 1. Figure 3 is a fragmentary view of a portion of Figure 2, enlarged for clarity. Figure 4 is a vertical section of Figure 3 in the plane of line 4-4 as viewed in the direction of the arrows. Figure 5 is a top plane view, partially in section, showing an alternative embodiment of the present invention with clamping means according to the state of art as known from EP-A-0 326 175. Figure 6 is a sectional view of the showing of Figure 5 as viewed in the plane of the line 6-6 and in the direction of the arrows, and; Figure 7 is a sectional view of Figure 6 as viewed on the plane of line 7-7 and in the direction of the arrows. DETAILED DESCRIPTION OF THE INVENTION Referring in detail to Figures 1, 2, 3 and 4, a typical tandemly arranged injection molding machine 11 includes fixed platens 5 and 10, moveable platens 15 and 20 and two molding stations A and B, each having molds 12 and 13 opened, closed and clamped under control of primary clamping means (PC) in well known fashion. That is, both molds can be opened separately or individually and can be clamped separately or in unison depending upon the manner in which the primary clamping means is programmed. Each mold means has an inlet means 14 and 16 which is an extension of the mold body and the inlet means is generally coaxial with the mold parting lines 17 and 18. The inlet means disclosed is a seamless adjunct to the mold body; obviously the inlet means could be designed as a separate piece part fastened by appropriate means to the mold body. Molding material is supplied to the mold stations A and B by a moveable molding material supply means 19, which in the present disclosure, is an extruder 21 having an attached nozzle means 22 and a nozzle valve 23. The extruder, nozzle means and valves are moveable as an assembly, to and fro, from mold station to mold station under control of a first power means P. As indicated in greater detail in Figures 3 and 4, the extruder 21, its nozzle 22 and valve 23 are moveable into registration with a mold inlet means such as is illustrated in Figure 3. In the arrangement of Figures 3 and 4, the moveable assembly includes a nozzle clamp means 24 and nozzle clamp power means 26. The nozzle clamp power means 26, secured to the nozzle means by a suitable fastener such as by bolts 27 and 28, comprises a piston-cylinder assembly supported in a body member terminating in a pair of dogs or claws 31 and 32, operable to slide into and make an interlocking connection with mating slots 33 and 34 formed in the mold inlet means as is most apparent in Figure 4. When the extruder, nozzle, nozzle valve, nozzle clamp and nozzle clamp power means are moved as an assembly and are positioned in register with the nozzle inlet means as shown in Fig 3 at Station A, the nozzle clamp power means 26 is energized to place the dogs 31 and 32 under a tensile stress as piston 36 bears down upon the nozzle 22 to seal the nozzle to the inlet means. Upon opening nozzle valve 23, moldable material is injected into the mold. Figures 5, 6 and 7 show an alternative arrangement wherein a moveable platen 37, having opposed hot runner manifolds 38 and 39 supplying moldable material to molds at stations A and B, supports nozzle clamp means 41 and 42 individual to each mold station. That is, in this arrangement the nozzle clamp means is separate from the molding material supply means and is fixed at each mold station. Suitable power means such as piston-cylinder assemblies 43 and 44, under control of nozzle clamp control means S₁C₁ are operable to seal nozzle means 46 to respective hot runner manifolds (mold inlet means) when the extruder 47 is moved into registry with each manifold inlet.

Claims: In an injection molding machine having a series of tandemly arranged molding stations (A, B) wherein each station includes a mold means (12, 13) and a mold inlet means (14, 16, 38, 39), movable supply means (19, 21, 37, 47) for introducing moldable material into said mold means (12, 13), nozzle means (22, 46) carried by said supply means (19, 21, 37, 47), power means (P) for moving said supply means (19, 21, 37, 47) operable to register said nozzle means (22, 46) with each said mold inlet means (14, 16, 38, 39), and nozzle clamp means (24) for sealing the nozzle means (22, 46) to mating mold inlet means (14, 16, 38, 39), characterized in that the nozzle clamp means (24) is carried by said supply means (19, 21, 37) and forms a unitary assembly together with the nozzle means (22, 46) which is moved from mold inlet means (14, 16, 38, 39) to mold inlet means. The machine of claim 1 characterized in that the mold means (12, 13) includes a mold parting line (17, 18) and the mold inlet means (14, 16) is disposed generally coaxially with said parting line. The machine of claim 2 characterized in that the mold inlet means (14, 16) is a seamless extension of the mold means (12, 13). The machine of at least one of the claims 1 - 3, characterized in that the nozzle clamp means (24) and the mold inlet means (14, 16, 38, 39) make an interlocking connection. The machine of claim 4 characterized in that the interlocking connection defines at least one dog (31, 32) and a cooperating slot (33, 34). The machine of claim 5 characterized in that the dog (31, 32) is carried by one of said inlet means (14, 16, 38, 39) and said nozzle means (22, 46), and the slot (33, 34) is formed on the other of said inlet means (14, 16, 38, 39) and said nozzle means (22, 46). The machine of claim 5 or 6 characterized in that the dog (31, 32) is fixed to said supply means (19, 21) and the slot (33, 34) is formed in said inlet means (14, 16, 38, 39). The machine of one of the claims 5 - 7 characterized in that the supply means (19, 21, 37) includes nozzle clamp power means (26) for placing a mating dog (31, 32) and slot (33, 34) under tensile stress while pressing the nozzle means (22, 46) to a mating mold inlet means (14, 16, 38, 39) to create a seal. The machine of at least one of claims 1 - 8 characterized in that the nozzle means (22, 46) includes a valve means (28) operable to seal the nozzle means (22, 46) when in transit from one molding station (A, B) to another molding station (B, A). The machine of at lest one of claims 1 - 9 including a primary clamp means (PC) for clamping mold means (12, 13) at each mold station (A, B) along a first axis and a secondary or nozzle clamp means (24) for clamping a nozzle means (22, 46) to a mold inlet means (14, 16, 38, 39) wherein the secondary clamp means (24) clamps along a second axis which is generally perpendicular to said first axis, The machine of at least one of the claims 1 - 10 characterized in that the mold inlet means defines a hot runner means (38, 39). The machine of claim 11 characterized in that the mold stations (A, B) are separated by a platen means (37) and a hot runner means (38, 39) is disposed between the mold means (12, 13) and said platen means (37) at each mold station (A, B). The machine of claim 12 characterized in that a platen means (37) common to a pair of adjacent mold stations includes the two hot runners (38, 39), the first hot runner (38) communicates with a first mold inlet said first mold inlet is disposed on one side of said platen, the second hot runner communicates with a second mold inlet said second mold inlet is disposed on an opposite side of said platen, supply means (47) are movable for introducing moldable material into each hot runner (38, 39), a nozzle (46) is carried by said supply means (47) said nozzle (46) being operable to connect with each hot runner (38, 39), and nozzle clamp means are carried by said supply means (37) for sealing said nozzle (46) to said first and second hot runners (38, 39) selectively whereby moldable material is supplied to each mold inlet individually via respective hot runners (38, 39), said nozzle clamp means making an interlocking connection with each hot runner (38, 39). The machine of claim 13 including valve means (23) in said supply means (47) for closing said supply means (47) when the nozzle (46) is in transit between said first and second hot runners (38, 39). A method of supplying each molding station (A, B) of an injection molding machine having at least two tandemly arranged molding stations (A, B) with moldable compound while making a sealing connection at respective stations characterized in that the steps of combining a moldable material supply means (19, 21, 47), a single nozzle means (22, 46) and a clamp means (24) into a unitary assembly and moving the assembly from station to station to seal the nozzle (22, 46) and to supply compound via said nozzle (22, 46) at each station (A, B) in sequence.

Inventors: PAULOVIC ANTON STEFAN, VON BUREN STEFAN, PAULOVIC, ANTON STEFAN, VON BUREN, STEFAN
Applicants: HUSKY INJECTION MOLDING, HUSKY INJECTION MOLDING SYSTEMS LTD.
Application year: 1990
Main classification: B29C45
IPC codes: B29C45