Plastic and nonmetallic article shaping or treating: processes – Forming continuous or indefinite length work – Of varying cross-sectional area or with intermittent...
Reexamination Certificate
2001-04-05
2004-03-16
Eashoo, Mark (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Forming continuous or indefinite length work
Of varying cross-sectional area or with intermittent...
C264S173170, C264S177160, C425S381000, C425S465000, C425S166000
Reexamination Certificate
active
06706229
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a molding method of a molded surface fastener which is made from thermoplastic synthetic resin material and has coupling elements independently and continuously molded integrally on the surface of a sheet-like base member, the Surface fastener, and a molding apparatus thereof. More specifically, it relates to a molding method of a molded surface fastener which can be molded to have various sizes from a fine size to a normal size, and is suitable for various uses in many fields, and which can be molded continuously and efficiently in a single step with a simplified apparatus, a molded surface fastener obtained by the method, and a molding apparatus thereof.
2. Description of the Related Art
Conventional molded surface fasteners are manufactured by various systems. A typical example thereof is a system of manufacturing fasteners by a complete batch system with the injection molding. Another typical system is a system where a die wheel having a lot of molding cavities for coupling elements on the peripheral surface thereof, is rotated in one direction, and in the meantime, molten resin material is continuously introduced to the peripheral surface of the die wheel, so that a sheet-like base member and coupling elements are continuously and integrally molded. According to these systems, it is possible to mold coupling elements having conventionally well known various shapes such as a palm shape or a hook shape.
Furthermore, there is another system, in which a lot of approximately T-shaped extruding holes are provided in an extruding die side by side, while an extruding hole is formed for a base member and communicates with the lower end of each T-shaped extruding hole. According to this system, by simultaneously extruding molten resin from both of the extruding holes, a plurality of pieces of ribs each having an approximately T-shaped cross section are continuously molded on a surface of the sheet-like base member, and then the molten resin molding material is cooled and solidified. Next, the ribs are cut with a predetermined thickness in a direction perpendicular to a drawing direction of the ribs or at a proper angle, while the sheet-like base member is left uncut. After this cutting, the sheet-like base member is drawn in the molding direction, so that the cut coupling elements are individually separated by a desired pitch. Thus, the molded surface fastener is manufactured.
In these molding methods, for example, in the technique of continuously molding surface fasteners on the die wheel, it is difficult to mold a coupling element with a complex form because of the limitation of its shape or size, if improvement of productivity is attempted. On the other hand, if a certain option to the shape or size of the coupling element is attempted to be given, the continuous molding is difficult to achieve, or the number of steps is increased so that the productivity may be lowered. In any case, the difference between advantage and disadvantage would be remarkably large.
On the other hand, in the case of adopting a system in which the drawing processing is applied after cutting the ribs of the molten resin molding material on the surface of the sheet-like base member from the extruding die in order to give a certain option to the sectional shape of a coupling head portion, three steps of extrusion molding, rib cutting, and drawing are required. Especially, a high processing accuracy is required for the step of rib cutting, so that the considerable labor and time are also needed for the maintenance and management thereof.
The present invention is made to solve such conventional problems. Specifically, it has an object to provide a molding method of a molded surface fastener, which can continuously perform the molding with a completely new molding mechanism, and whose maintenance and management are easy, and whose productivity is high, and which has coupling elements each capable of being molded with new shapes until now and by various sizes, and a molded surface fastener obtained by the method, and a manufacturing apparatus thereof.
SUMMARY OF THE INVENTION
Such an object can be achieved by first through the third aspects of the present invention.
According to the first aspect of the present invention, there is provided a molding method of a molded surface fastener for continuously and integrally molding a sheet-like base member and a multiplicity of coupling elements, comprising the steps of: continuously extruding molten resin material from a first extruding hole extending in a width direction of a first extruding nozzle arranged on the downstream side in an extruding direction of the molten resin material via an extruding die of an extruding machine; passing the molten resin material extruded from the first extruding nozzle through a second extruding nozzle which is arranged at a front surface of the first extruding nozzle and has a second extruding hole corresponding to the first extruding hole; and relatively vibrating the first extruding nozzle and the second extruding nozzle in the width direction in such a way that the respective extruding holes facing each other mutually cross, wherein one of the first extruding hole and the second extruding hole includes a plurality of longitudinal rectangular openings arranged in the width direction, and the other extruding hole has coupling-element-molding openings arranged so as to correspond to the rectangular openings.
The most distinguishing feature of this invention is to relatively vibrating the first extruding nozzle which is arranged on the downstream side of the molten resin extruded from the extruding die of the extruding machine and has a multiplicity of openings, and the second extruding nozzle which is arranged in a freely slidable way at the front surface of the first extruding nozzle at the downstream side thereof and has a multiplicity of openings of which number corresponds to that of the openings of the first extruding hole so that the respective corresponding extruding holes may cross each other.
When the molten resin extruded from the extruding die in a sheet-like form passes through the first extruding nozzle and the second extruding nozzle which are relatively vibrating in the width direction, the molten resin is extruded through a communicating space of the first and second extruding holes by the relative vibration of the first extruding hole and the second extruding hole while sequentially moving from a tip of a coupling head portion to a stem portion of each coupling element. While the coupling elements are molded in the extruding direction, the sheet-like base member is continuously molded by the base-member-molding openings of the first extruding nozzle and the second extruding nozzle. At this time, a rising base end of the stem portion is molded integrally on the sheet-like base member.
Preferably, the first extruding hole may have the coupling-element-molding openings, and the second extruding hole may have the longitudinal rectangular openings, and a periphery of each of the longitudinal rectangular openings is formed to have a tapered surface gradually enlarged toward the downstream side in the extruding direction, and that the second extruding nozzle is vibrated on the front surface of the first extruding nozzle. Or alternatively, the first extruding hole may have the longitudinal rectangular openings, and the second extruding hole may have the coupling-element-molding openings, and a periphery of the coupling-element-molding opening is formed to have a tapered surface gradually enlarged toward the downstream side in the extruding direction, and the second extruding nozzle is vibrated at the front surface of the first extruding nozzle.
Since the periphery of the longitudinal rectangular opening of the second extruding nozzle is made to be a tapered surface gradually enlarged toward the extruding direction, or since the periphery of the coupling-element-molding opening of the second extruding nozzle is made to be a tapered surfac
Eashoo Mark
Finnegan, Henderson Farabow, Garrett and Dunner L.L.P.
YKK Corporation
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