Plastic article or earthenware shaping or treating: apparatus – Female mold and charger to supply fluent stock under... – With product ejector
Patent
1988-04-15
1990-01-02
Thurlow, Jeffery
Plastic article or earthenware shaping or treating: apparatus
Female mold and charger to supply fluent stock under...
With product ejector
249 67, 249 68, 425554, 425444, 4254519, 425441, 264334, B29C 4542, B29C 4566, B28B 710
Patent
active
048910023
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to product ejectors for use in injection molding machines and, particularly, to a product ejector in a direct-acting type mold clamping system in which a ball screw is driven by a servomotor to move a moving platen fixedly mounted to a ball nut threadedly engaged with the ball screw, thereby carrying out mold clamping.
2. Description of the Art
In an injection molding machine, there is known a product ejector for removing a product from a mold, which is of such a type that, during rearward movement of a moving platen toward a rear platen, a rod fixed to the rear platen pushes an ejector plate, short of a point of time mold opening is completed, to project a product ejector bar fixedly mounted to the ejector plate, toward the mold mounted on the moving platen, thereby ejecting a product from the mold. A product ejector is also known, which is of such a type that a driving source separate from a driving source for a mold clamping system is employed to drive a product ejector bar to project the same, thereby removing a product from a mold.
A direct-acting type mold clamping system also has been developed, in which a ball screw is rotated by a servomotor, to move a moving platen which is movable together with a ball nut threadedly engaged with the ball screw, to thereby carry out mold closing, mold clamping and mold opening.
It is required for the above direct-acting type mold clamping system to set a length of the ball screw supported by a rear platen, to a considerably large value corresponding to a moving stroke of the moving platen. It is also required to prevent the ball screw and the platen from interfering with each other at a position where mold opening is completed. As a result, the spacing distance between the rear platen and the moving platen becomes long. Accordingly, if the rod for pushing the product ejector bar mounted on the side of the moving platen is fixed to the rear platen, the rod becomes long, so that deflection might occur or a problem might arise as to strength. On the other hand, if an attempt is made to carry out driving of the product ejector bar without the use of the long rod, a driving source for ejection of a product is especially required, making the injection molding machine expensive.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a product ejector in a motor-driven, direct-acting type mold clamping system for an injection molding machine, in which an exclusive product can be ejected without the necessity of a driving source and which has a simple structure, and whereby is possible to reduce the length of a rod for transmitting driving force to an ejector bar.
In order to achieve the above-mentioned object, in a product ejector in a direct-acting type mold clamping system in which a ball screw is rotated by a motor to move a moving platen fixedly mounted to a ball nut threadedly engaged with the ball screw, thereby carrying out mold clamping, the arrangement of the invention is such that a rod is mounted on a forward end of the ball screw, an ejector plate is fixedly mounted to an end of an ejector bar on the side of the rod so as to be engageable with the rod. The ejector bar is arranged within a bore provided in the moving platen in such a manner that the ejector bar extends through the bore and is slidable, and a spring is arranged between the ejector plate and the moving platen for biasing the ejector bar toward the ball screw.
As described above, the arrangement of the invention is such that the rod mounted to the forward end of the ball screw extending to a position near the moving platen pushes the ejector bar toward a mold just before completion of mold opening motion of the moving platen, to eject a product from the mold, By virtue of such arrangement, the product can be ejected and removed without the use of a special driving source for ejection of a product and therefore has a simple structure. The rod can be reduced in length so that no particula
REFERENCES:
patent: 3158905 (1964-12-01), Havlik
patent: 3388431 (1968-06-01), Aoki
patent: 3669593 (1972-06-01), Cyriax
patent: 3702750 (1972-11-01), Veneria
Inaba Yoshiharu
Tokunaga Shigeo
Fanuc Ltd.
Thurlow Jeffery
Vargot Mathieu
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