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
2001-12-21
2004-01-13
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...
C264S328900, C425S566000
Reexamination Certificate
active
06676401
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an in-mold gate opening and closing mechanism and a metal mold for injection molding.
2. Description of the Prior Art
Briefly speaking, a method for injection molding of synthetic resin is carried out by a cycle of picking up a solidified molded article from a metal mold by opening the metal mold (mold opening) after tightening an upper mold (fixed die or female die) and a lower mold (movable die or male die), filling the metal mold with melted synthetic resin, and cooling the same. At this time, since the molded article is provided with a resin part, a so-called “spool runner gate”, it is necessary to cut off the resin part by a certain method.
As a classical method, the gate portion (resin part) is cut off by cutting pliers, etc., various types of in-mold gate opening and closing mechanisms have been proposed and carried out as technical objects of improvement in production efficiency, a lowering of production costs, improvement in aesthetic evaluation, etc.
As an in-mold gate opening and closing mechanism, a system in which a gate opening and closing pin incorporated in advance in a mold is moved in line with opening movement of the mold, and is operated to the gate portion by an exclusively attached fluid pressure means, and the gate portion is cut off, a system in which the gate opening and closing pin is actuated by movement of a movable mold when opening the mold, and a tunnel gate system have been publicly known.
Since a conventionally known in-mold gate opening and closing mechanism is constructed so that a gate opening and closing pin is actuated in line with movement of an exclusively attached fluid pressure means and a movable mold, the mechanism is large-sized and complicated. Also, in the former system, a process to open and close a gate when opening the mold is required, and a loss in time is produced to carry out the process (cf. Japanese Patent No. 2966707).
In a case of multi-gate molding or molding to produce a plurality of articles, the number of gates is increased, and positioning of the gates becomes cumbersome. Therefore, in an in-mold gate opening and closing mechanism of the conventional system, there is a difficulty or a problem in that design and production of metal molds become complicated and increase costs.
Further, in the in-mold gate opening and closing mechanism of the conventional system, there is another shortcoming in that an aesthetic cut surface cannot be obtained because the gate portions are cut off after resin is hardened.
SUMMARY OF THE INVENTION
In view of the above-described problems and shortcomings, it is therefore an object of the invention to provide an in-mold gate opening and closing mechanism, whose structure is compact and simple, capable of facilitating incorporation of a cold runner die, a hot runner die, etc., into a mold and adjustment of gate balance, and a metal mold for injection molding.
The in-mold gate opening and closing mechanism and metal mold for injection molding according to the present invention is featured in the following construction:
1. (Refer to FIGS.
1
~
10
and
15
~
29
) An in-mold gate opening and closing mechanism constructed so that a gate pin disposed at a gate in a mold is moved on the basis of resin pressure in the gate, in which the gate is opened by the gate pin escaping from the gate when the resin pressure exceeds an appointed pressure level when filling resin, and the gate is closed by the gate pin moving the gate direction when the resin pressure is lowered from the appointed pressure level when a filling of the resin is completed, wherein a void for a gate is provided at the upper end part of a base body, a guide groove is provided continuously from the gate void, and a gate pin is disposed therein; the corresponding gate pin is pressed in the direction of the above-described gate void by a spring disposed in the above-described base body, and a mechanism for adjusting spring pressure of the corresponding spring is provided; the corresponding gate pin escapes from the gate when the resin pressure exceeds a pressing force of the spring, which is adjusted by a mechanism for adjusting the spring pressure when filling resin to open the gate; and the above-described gate pin is moved in the gate direction by a pressing force of the spring adjusted by the mechanism for adjusting the above-described spring pressure when the resin pressure is lowered below an appointed pressure level after a filling of the resin is completed.
2. (Refer to
FIG. 1
) An in-mold gate opening and closing mechanism, in which one unit having the following component elements (A), (B) and (C) incorporated on the surface and in an inner space of the base body consisting of a metallic block is formed and incorporated in a metal mold, and a runner gate is opened and closed from the direction orthogonal to or the same direction as the direction of the gate.
(A) A gate void is formed at the upper end portion of a base body, and a gate pin is disposed in a guide groove provided continuously from the gate void.
(B) A columnar space is provided at the lower part of the above-described gate void inside the above-described base body, a spring and a moving cylinder in which the spring is accommodated are inserted into the columnar space, and the lower end of the above-described gate pin is engaged with and fixed at the rear end of the moving cylinder, wherein the above-described gate pin is always pressed in the direction of the gate void by a force of the above-described spring.
(C) A spring pressure adjusting nut that presses the rear end of the above-described spring is provided in a screwed-in state so as to turn clockwise and counterclockwise at the open end side of the above-described moving cylinder of the base body, wherein a pressing force acting on the gate pin can be increased by turning the corresponding spring pressure adjusting nut in the direction of contraction of the spring, and the pressing force acting on the gate pin can be decreased by turning the adjusting nut in the reverse direction of the corresponding turning direction.
3. (Refer to
FIGS. 2 and 3
) An in-mold gate opening and closing mechanism, in which one unit having the following component elements (A), (B) and (C) incorporated on the surface and in an inner space of the base body consisting of a metallic block is formed and incorporated in a metal mold, and a runner gate is opened and closed from the direction orthogonal to or the same direction as the direction of the gate.
(A) A gate void is formed at the upper end portion of a base body, and a gate pin is disposed in a guide groove provided continuously from the gate void.
(B) A columnar space is provided at the lower part of the above-described gate void inside the above-described base body, and a moving cylinder is inserted into the corresponding columnar space, a center shaft, which is inserted into the spring, is accommodated in the corresponding moving cylinder, and the lower end of the above-described gate pin is engaged with and fixed at the rear end of the moving cylinder, wherein the above-described gate pin is always pressed in the direction of the gate void by a force of the above-described spring.
(C) A center shaft is provided between a bearing hole prepared at the tip end side of the above-described base body and a bearing member that presses the rear end of the above-described spring that is fixed in a columnar hole at the rear end side of the base body, the above-described moving cylinder and spring are disposed at the corresponding center shaft, a stop bushing and a worm wheel are further disposed thereat, and the corresponding worm wheel is engaged with a rotatable worm, wherein as the corresponding worm is rotated, the above-described worm wheel that is interlocked with the corresponding worm is rotated, the pressing force of the spring is adjusted by the center shaft moving in the direction of tightening the spring by clockwise rotation on the basis of engagement with a bearing member by a s
Ohno Makoto
Saito Toshio
Fisa Corporation
Heitbrink Tim
Roylance Abrams Berdo & Goodman LLP
LandOfFree
In-mold gate opening and closing mechanism and metal mold... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with In-mold gate opening and closing mechanism and metal mold..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and In-mold gate opening and closing mechanism and metal mold... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3190592