Plastic article or earthenware shaping or treating: apparatus – Female mold and charger to supply fluent stock under... – With means to lock mold in closed position
Reexamination Certificate
1998-12-01
2001-03-20
Mackey, James P. (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Female mold and charger to supply fluent stock under...
With means to lock mold in closed position
C425S451900, C425S589000, C100S231000, C100S25800A
Reexamination Certificate
active
06203312
ABSTRACT:
BACKGROUND TO THE INVENTION
The present invention relates to a clamping apparatus for a tiebarless injection moulding machine.
Tiebarless injection moulding machines offer better access to the moulding tool, and thereby facilitate and reduce the set up time of the machine each time the moulding tool is changed. Of course, as a tiebarless moulding machine does not have tiebars to absorb the huge forces transmitted to the platens and moulding tool during a moulding process it is imperative to have a properly designed mechanism to absorb the forces. In this respect, it is necessary that the two mould halves forming the moulding tool remain accurately aligned with each other whilst the two halves are pressed together and under application of high pressure.
Several attempts have been made to provide a tiebarless injection moulding machine which is able to deal with the clamping forces in a satisfactory manner.
U.S. Pat. No. 5,354,196 describes a clamping apparatus for a tiebarless injection moulding machine having a machine frame, the clamping apparatus comprising a fixed platen fixed to the machine frame, a movable platen supported by said machine frame, drive means for moving said movable platen towards and away from said fixed platen, and a clamping structure for maintaining the fixed and movable platens in a clamping position, wherein, in the clamping position of the fixed and movable platens, a respective part of the clamping structure is in force transmitting relationship with each of the fixed and movable platens such that the clamping structure is able to absorb clamping forces.
In the arrangement of U.S. Pat. No. 5,354,196 the clamping structure absorbs the clamping forces, whereby the base machine frame is kept from bending, and whereby a tight fit between the two platens is ensured. The arrangement provides a double structure in which the machine frame is isolated from the deforming effects of the clamping forces. Transmission of the clamping forces to the platens is achieved by way of pivotal joints.
However, the structure of U.S. Pat. No. 5,354,196 is somewhat complex and presents a number of practical limitations. Most notably, it has been found difficult to provide pivotal joints which can reliably transmit the huge clamping forces required, whilst preserving the rotational freedom required between the machine frame and the clamping structure.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a clamping apparatus for a tiebarless injection moulding machine which reduces the limitations of prior proposals.
According to the present invention, in a clamping apparatus of the type defined, the movable platen is in force transmitting relationship with said clamping structure by way of a force transmission member mounted for displacement along said machine frame, and the force transmitting parts of the clamping structure each have a curved surface which abuts a respective one of the fixed platen and the force transmission member.
An embodiment of clamping apparatus of the invention has the advantage that no pivots nor tilting elements are required to interconnect parts of the clamping apparatus. Furthermore, as the clamping structure absorbs all of the substantial clamping forces, the machine frame or base remains always free from stress during the clamping operation.
Preferably, the fixed and movable platens, and the force transmission member, are aligned along a longitudinal plane which incorporates a centre line of the clamping apparatus, and each of the force transmitting parts of the clamping structure abuts the respective one of the fixed platen and the force transmission member at contact points on or near to said longitudinal plane.
In an embodiment, the clamping structure is supported on said machine frame by adjustable support means which enable the position of said contact points to be adjusted.
In one construction, the curved surfaces of the force transmitting parts of the clamping structure are each defined by a respective roller carried by the corresponding force transmitting part.
In an embodiment, linear guide means support and guide said first movable platen and said force transmission member, the displacement of said force transmission member being limited in one direction by stops carried by the machine frame, and being limited in the other direction by the abutment of force transmitting parts of said clamping frames.
The movable platen is preferably mounted for sliding movement along the machine frame, and the force transmission member is similarly mounted for sliding movement along said machine frame.
For example, in an embodiment, one or more linear guide rails extend along the machine frame, and the movable platen and the force transmission member are mounted for sliding movement along said linear guide rails.
In an embodiment, stop means for limiting the displacement of said force transmission member in a direction towards the fixed platen are provided.
The clamping structure is preferably supported by, but movable with respect to, said machine frame.
In a currently preferred embodiment, the clamping structure has two, substantially parallel, clamping frames, each said clamping frame being substantially U-shaped and having first and second spaced arms defining the force transmitting parts thereof, the first arm of each clamping frame abutting said fixed platen, and the second arm of each clamping frame abutting said force transmission member.
Preferably, each first arm abuts an outer surface of said fixed platen, and each second arm abuts an outer surface of said force transmission member.
In an embodiment, each clamping frame has a recess or cutout defining upper and lower longitudinal members of the clamping frame. Support means for the clamping frame are arranged to abut said upper longitudinal member thereof.
In an embodiment, each said support means comprises a pin resiliently supported and guided inside a bracket or plate fixed to said machine frame, and a rimmed wheel or roller connected to the top of said pin, said wheel or roller holding and guiding said clamping frame by means of said upper longitudinal member.
Each said clamping frame may be supported on rollers or wheels carried by the machine frame. Furthermore, the rollers or wheels may be resiliently mounted.
In a preferred embodiment, said drive means incorporate said force transmission member.
The drive means may be powered by any appropriate means. For example, the drive means may be hydraulic, hydro-mechanical or electromechanical.
In an embodiment, said drive means may comprise a hydraulic cylinder and piston unit, the hydraulic cylinder being coupled to said force transmission member, and the piston being coupled to said movable platen.
Alternatively, said drive means may comprise a toggle mechanism coupled between said force transmission member and said movable platen.
Preferably, said clamping structure is arranged to be elastically deformed by the application of clamping forces thereto.
REFERENCES:
patent: 4961372 (1990-10-01), Leonhartsberger
patent: 5249951 (1993-10-01), Leonhartsberger et al.
patent: 5297952 (1994-03-01), Leonhartsberger
patent: 5354196 (1994-10-01), Ziv-Av
patent: 5536166 (1996-07-01), Schad
patent: 5556656 (1996-09-01), Lampl et al.
patent: 5578333 (1996-11-01), Schad et al.
patent: 5593711 (1997-01-01), Glaesener
patent: 5620723 (1997-04-01), Glaesener et al.
patent: 5624695 (1997-04-01), Glaesener et al.
patent: 5633024 (1997-05-01), Ziv-Av
patent: 5645875 (1997-07-01), Glaesener et al.
patent: 5650182 (1997-07-01), Füller et al.
patent: 5660783 (1997-08-01), Urbanek et al.
patent: 5700502 (1997-12-01), Hehl
patent: 5762984 (1998-06-01), Wimbauer
patent: 5783231 (1998-07-01), Füller et al.
patent: 5800843 (1998-09-01), Kappelmüller et al.
patent: 2064415 (1981-06-01), None
patent: 2-18009 (1990-01-01), None
patent: 8-276482 (1996-10-01), None
Industrias Romi S.A.
Mackey James P.
Steinberg & Raskin, P.C.
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