Plastic article or earthenware shaping or treating: apparatus – Female mold and charger to supply fluent stock under... – With means to cause relative movement between mold and charger
Patent
1986-04-11
1988-02-23
Woo, Jay H.
Plastic article or earthenware shaping or treating: apparatus
Female mold and charger to supply fluent stock under...
With means to cause relative movement between mold and charger
2643288, 26432811, 425576, 425589, 425595, B29C 4508, B29C 4566
Patent
active
047267577
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to injection moulding apparatus, and in particular, although not exclusively, to an injection moulding apparatus of the so-called rotary turret kind in which a plurality of mould sets are carried on a turntable, rotation of the turntable enabling the mould sets to be moved successively to an injection station at which each mould set is clamped firmly closed and molding material is injected into the mould cavity.
2. The Prior Art
Rotary turret injection moulding machines in which the turntable is indexed around to bring the mould sets in turn to the injection station are known. However, the turntables are driven intermittently, and this can cause problems, especially when there is a large number of mould sets and a large mass is involved.
SUMMARY OF THE INVENTION
The present invention provides a solution to this problem. In accordance with a first aspect of the invention, an injection moulding apparatus comprises a turntable, drive means for continuously rotating the turntable, a plurality of mould sets carried on the turntable, and a clamping and injecting assembly including means for clamping each mould set closed and means for injecting moulding material into the clamped mould set, the clamping and injecting assembly being mounted for reciprocal movement along an arcuate path in synchronism with the rotation of the turntable.
With such an arrangement the difficulties encountered in repeatedly starting and stopping rotation of a turntable having large inertia are avoided, the clamping and injecting assembly which may have comparatively small inertia being driven instead.
In a preferred construction the turntable rotates about a central shaft and the clamping and injecting assembly includes a support member and an arm journalled on the shaft and connected to the support member for guiding the member concentrically with the turntable during reciprocation of the clamping and injecting assembly.
To facilitate synchronous movement of the clamping and injecting assembly with the turntable it is expedient for latching means to be provided for latching the clamping and injecting assembly to the turntable to be moved therewith during a forward stroke, means being provided for driving the clamping and injecting assembly in the opposite direction through a return stroke.
In known injection moulds the mould parts which form the mould cavity are generally guided for movement towards and away from each other by guide rods which extend between them. The guide rods are inconvenient because they impede access to the opened mould, whereby removal of the moulded articles is hindered.
In accordance with a second aspect of the invention a simple answer to this problem is achieved by an injection moulding apparatus comprising first and second mould parts movable relative to each other between open and closed positions, said mould parts defining a mould cavity in the closed position thereof, and the first mould part being mounted on a support characterised in that the second mould part is arranged to pivot about an axis fixed with respect to the first mould part during said movement between the open and closed positions of the mould parts.
A pivotal connection between the mould parts enables the movable part to be displaced easily to an open position in which it is substantially clear of the other part, whereby unimpeded removal of the moulded articles from the mould is facilitated. It is preferable that the movable part be capable of rotating through at least about 90.degree. between the open and closed positions.
As mentioned above, in known injection moulds the parts which form the mould cavity are generally guided for movement towards and away from each other by guide rods. In order to ensure that the parts will close properly together they must be accurately aligned. Even a small misalignment can result in the moulded articles being unacceptable and having to be rejected.
In accordance with a third aspect the present invention proposes a solut
REFERENCES:
patent: 2419089 (1947-04-01), Quarnstrom
patent: 3293691 (1966-12-01), Osgood
patent: 3856444 (1974-12-01), Saltel
patent: 4072458 (1978-02-01), Schlieckmann
patent: 4186161 (1980-01-01), Ulmschneider et al.
Heitbrink Timothy W.
The World Health Organisation
Woo Jay H.
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