Plastic article or earthenware shaping or treating: apparatus – Female mold and charger to supply fluent stock under... – With means between charger and mold to cut off flow of...
Reexamination Certificate
1995-04-12
2001-05-08
Heitbrink, Tim (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Female mold and charger to supply fluent stock under...
With means between charger and mold to cut off flow of...
C425S382400
Reexamination Certificate
active
06227841
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an extruder assembly for an injection moulding machine comprising a valve and a pinned screw point.
BACKGROUND OF THE INVENTION
Extruder assemblies for injection moulding machines include piston screw that both reciprocate and rotate and includes a screw point at its leading end. The piston screw moves forward to inject melt and then retracts to take on new molten material to repeat the process.
Screw point that are currently being used generally have larger cross sections than screw points previously used. This increase results in an increase in the axial forces which are more difficult to overcome and also the response times are longer. This causes the material temperature to rise within the plasticizing screw, with attendant degradation of the material and losses in the injectable volume. The result of which is defects of the molded objects, which must then be rejected. In addition, the greater the axial forces, the higher the temperature will become and the greater the friction wear on the parts will be.
OBJECT OF THE INVENTION
The object of the invention is to limit the opening between the pressure ring of the injection molding machine and the valve, and to enable permanent recentering of the valve while reducing wear on the parts of the assembly.
This object is attained by an assembly comprising a screw point having a pin and a valve, that functions as a check valve located in front of the piston screw. This invention is characterized in that the pin includes only two support points located on its ends. These support points are formed as flats oriented at the angle that corresponds to the angle of the valve seat.
In another embodiment, the pin is cylindrical and non-floating in form, and is integral with the screw point.
In another embodiment, the pin is floating, self-centering and replaceable.
In another embodiment, the pin is not cylindrical.
In another embodiment, the pin has the form of a floating or non-floating fin.
Further characteristics and advantages of the present invention will become more apparent from the ensuing detailed description, in conjunction with the accompanying drawings.
REFERENCES:
patent: 5112213 (1992-05-01), Oas
patent: 2617977 (1973-10-01), None
patent: 0212224 (1987-03-01), None
patent: 1335824 (1973-10-01), None
Patent Abstracts of Japan, vol. 10, No. 281 (M-520) (2337), Sep. 25, 1986, & JP-A-61 100 427 (Jiyuken Kogyo).
Patent Abstracts of Japan, vol. 11, No. 94 (m-574) (2541), Mar. 25, 1987, & JP-A-61 246 -031 (Japan Steel Works).
Brinks Hofer Gilson & Lione
Heitbrink Tim
Nestal Machinery Ltd.
LandOfFree
Valve and pinned screw point assembly does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Valve and pinned screw point assembly, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Valve and pinned screw point assembly will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2494384