JP2681238B2 - Flexible screw for conveyor with polymer wire containing fiber bundle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible screw for a conveyor, which is mainly used in a device for conveying containers such as glass and plastic bottles.

[0002]

2. Description of the Related Art For carrying containers such as glass and plastic bottles (hereinafter simply referred to as containers) filled with a liquid or the like, a steel rope is coated with a resin,
A screw in which a wire made of metal such as steel is spirally wound around a resin layer is used. A container transporter that uses screws with this type of structure arranges the screws in parallel at regular intervals, suspends the containers between the screws (usually hooks the flange at the neck of the container onto the shaft), and rotates the screws. The container is configured to be conveyed by the above.

[0003] This device moves a container by a conveyance principle which is completely different from a usual belt conveyor or roller conveyor used for container transportation, that is, a contact friction between a screw and a neck of the container causes the container to move. The positioning of the container is accurate, the manufacturing process line can be automated, the structure of the device itself is simple and small, and the equipment cost is low.

By the way, since the above-mentioned screw is a steel wire wound spirally, the neck (including the collar) of the container which comes into contact with the wire is easily worn or damaged by the high-speed rotation of the screw. In particular, in the case of a container filled with carbonated beverages, more attention must be paid to the damage to the container.

Therefore, the present inventor has considered that a twisted fiber bundle made of nylon or the like is used as a core instead of the steel wire, and a wire coated with a polymer on the core is used. Since the surface layer of the cored wire is made of resin,
It has an advantage that the degree of wear of the container is lower than that of the steel wire.

[0006]

The wire containing a core is generally fed out in one direction under a constant tension, and a molten polymer is extruded onto the core from a die arranged on the axis of the direction of travel of the core. -Manufactured by coating and cooling it. However, as the molten polymer solidifies by cooling, buckling occurs in the core due to the difference between the shrinkage rate of the polymer and that of the core. The buckled wire has the property of expanding when tension is applied to the wire due to the contraction of the core.

In the above conveying device, the container moves while rotating due to the sliding friction generated by the high-speed rotation of the screw. Therefore, when the container passes through the wire rod, a force in the direction of increasing the winding pitch ( In other words, the force of expanding the spiral interval of the wire rod) acts repeatedly. Under such conditions, the wire rod will eventually stretch due to the above-mentioned property, and will stretch on the rod to become loose, and the winding pitch of the wire rod will change accordingly. Pitch irregularity makes the transportation speed of the container indefinite, and in extreme cases, the transportation becomes impossible.

In view of the above circumstances, the present inventor has previously proposed to use a polymer wire rod with a fiber bundle in which the buckling rate of the core body is 3.0% or less. However, since the capacity of the container has increased in recent years, the force applied to the wire rod during container transportation has become even greater, or there has been a demand for something that can accommodate large changes in the operating environment temperature. However, the requirements for wire rods have become more severe.

Even under such severe conditions, since the flexible screw for the conveyor which does not have the pitch disturbance due to the container transportation and the change of the operating environment temperature cannot be provided, the present inventor has conducted various studies, and as a result, Buckling rate is 0.3
It has been found that the purpose can be achieved by using a polymer wire rod containing a fiber bundle in which the content is less than or equal to%.

[0010]

That is, according to the present invention, a buckling rate is 0.3% on a flexible rod in which a resin layer is provided on a steel rope.
The present invention relates to a flexible screw for a conveyor, which is formed by spirally winding a polymer-coated wire having a core made of the following fiber bundles.

In the present invention, the buckling rate means the length L when the polymer of the polymer wire is removed and the core is tensioned with a force of 1/1000 of the tensile strength of the core and the length of the wire before removal of the polymer. It is expressed in percentage of the initial length L ₀ of the difference between the L _0.
That is, the buckling rate ε is

[0012]

(Equation 1)

It is obtained from the equation (3).

In the screw of the present invention, the buckling rate of the core in the wire is 0.3% or less, preferably 0.1% or less, more preferably 0.05% or less. In the wire rod having "," the elongation is practically zero. As a result, the winding pitch of the wire does not change even when it is used for carrying a large-capacity container or when the environmental temperature changes significantly.

The material of the fiber bundle serving as the core of the wire rod in the present invention is not particularly limited as long as it acts as a tension member of the wire rod. Examples of the fiber bundle include natural fibers [(vegetable fibers such as cotton, flax, cannabis and coconut fibers), (animal fibers such as wool and silk)], semi-synthetic fibers (eg acetate), synthetic fibers [eg polyamide fibers (Eg 6-nylon etc.), aramid fiber (eg Kevlar etc.), polyester fiber (eg Tetron etc.), polyacrylonitrile fiber (eg acrylic fiber, modacrylic fiber etc.), polyvinyl alcohol fiber, polyvinyl chloride fiber, poly Examples thereof include vinylidene chloride fiber, polyolefin fiber (eg, polyethylene, polypropylene, etc.), polyurethane fiber, inorganic fiber (eg, glass fiber, graphite fiber, boron fiber, various metal fibers, etc.). Among them, Kevlar is suitable in terms of high strength, fatigue resistance, heat resistance, low creep property, and the like. The core is usually prepared by twisting a number of fibers, and the thickness of this fiber bundle depends on the material of the core and the outer diameter of the wire, but it is 1,000 to 15,000 denier, preferably 1,500 to 9,000 denier. So, the number of twists in the fiber bundle is
666 to 10,000, preferably 1,000 to 6,000.

As the polymer of the coating material with which the core is coated, any polymer can be used as long as it can be melt extruded by a die. However, since the container is transported by the rotation of the screw in the container transport device that is used for the screw, it is important for product and safety that the neck of the container (including the collar) that is in direct contact with the wire is not worn or damaged. Is. Therefore, it is preferable that the polymer has good wear resistance, flexibility, rolling property, slidability, and the like, and has a small dynamic friction coefficient. Such polymers include, for example, polyalkylenes (for example, various polyethylenes, especially ultra-high-molecular-weight polyethylenes or those having improved injection moldability based on the same, for example, Lubemer (manufactured by Mitsui Petrochemical Industry Co., Ltd.) as a commercial product, Polypropylene etc.], polyether (eg polyacetal, polyphenylene ether etc.), polyamide (eg 6-nylon, 6,6 nylon, 11-nylon etc.), fluororesin (eg polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether) Copolymers, etc.), polyesters (eg, polyethylene terephthalate, polybutylene terephthalate, etc.) and the like.

There is no particular limitation to obtain a polymer-coated wire having a core buckling rate of 0.3% or less using the above fiber bundle material for core and coating material, but the following production method is used. Is the best. That is, a core made of a fiber bundle is fed in one direction under a constant tension, and a molten polymer is extruded onto the core from a die arranged on the axis of the moving direction of the core.
It is a method of coating and cooling the extrudate while constraining the extrudate to a certain shape with a die to the extent that the extrudate does not expand at least by the internal pressure due to the tension of the core. This manufacturing method is similar to the conventional method of manufacturing this type of wire rod, but the major difference from the conventional method is that the extrudate is shaped into a uniform shape with a die of a certain length while maintaining the state in which tension is applied to the core ( Usually, it is cooled while constraining to a cylindrical shape.

This manufacturing method will be described in more detail. FIG. 3 is a vertical cross-sectional view for explaining the manufacturing method principle. In FIG. 3, the core body 1 made of a fiber bundle is in a direction opposite to the tension T in a state where a constant tension T in the arrow direction is applied. It is sent out at a constant speed. The molten polymer 2 ′ is extruded and coated on the core body 1 through the die 3, and moves in the outlet direction of the die 3 as the core body 1 advances. The die 3 has a cylindrical elongated portion 3a having a constant diameter, unlike a usual melt extrusion die,
The extrudate is cooled while being restrained by the long portion 3a. The molten polymer 2'begins to solidify from the contact portion with the elongated portion 3a, and the solidification progresses in a conical shape toward the central portion where the core 1 is located. The constraint of the molten polymer by the die is performed to the extent that the extrudate does not expand due to the internal pressure due to the tension T of the core body. Therefore, it is important that the cylindrical elongated portion 3a has such a length that buckling does not occur in the core even when the extrudate is opened. This length depends on the type of polymer being melted,
It is appropriately determined according to the delivery speed of the core.

In FIG. 3, when the position where the molten polymer 2'is solidified to the central portion is A and the position where the solidified polymer 2 is at room temperature to the inside is B, the behavior of this type of fluid substance is generally extruded. It was found that the melt begins to solidify from the outside toward the center with the core, and most of the buckling occurs in the section from the solidification reaching the center to the room temperature of the extrudate. Therefore, the tension T applied to the core while restraining the melt extrudate with a die as described above is
It suffices that the force is sufficient to extend the buckling within the distance between A and B, and it is preferable to apply a tension suitable for the tensile strength of the material of the core and the delivery speed to the core. This allows
The obtained wire rod theoretically has a stress and a buckling of almost zero.

There is no limitation on the die used in the above manufacturing method,
Known dies used in the melt extrusion technology of wire are sufficient. In this manufacturing method, a cylindrical long portion is further joined to the downstream side of these dies (see US Pat. No. 3,928,525).
It is preferable to use

The flexible screw of the present invention does not bend due to rotation and is sufficiently rigid to transmit the rotational torque applied from one end of the screw to the other end, and is flexible so that it can be easily laid along a curved conveyance line. It is important to have both sex. Both of these properties are obtained by constructing the flexible rod from steel rope. As such a steel rope, several (or several tens) strands (having a diameter of 0.2 to 10) made of metal such as steel, nickel, cobalt and alloys thereof are used.
It is preferable to have a structure in which several strands are further twisted on a strand in which about 2.0 mm) are twisted together.

The resin layer provided on the steel rope coats the rough surface of the steel rope evenly and evenly, but since it directly contacts the neck and the collar of the container and slides at high speed, it is similar to the coating material for the wire rod. It is required to have excellent wear resistance and low contact resistance. Therefore, the resin material may be the same as the coating material, and is omitted here. The resin layer may be provided by using a usual extrusion coating technique. For example, a method is shown in which a molten resin material is extruded and coated on a steel rope from a die arranged on the axis of the traveling direction of the steel rope while feeding the steel rope in one direction under a constant tension. Although the thickness of the resin layer depends on the use and size of the screw, it is usually 0.1
It is about 2.0 mm, preferably about 0.2 to 0.6 mm.

The spiral winding of the wire rod around the flexible rod may be carried out slowly at room temperature while utilizing the stress relaxation of the wire rod. In addition, the winding pitch is appropriately determined based on the size of the container, the number of conveyed containers, the screw rotation speed, etc., in consideration of the container conveying speed.
However, the pitch does not have to be constant over the entire length of the screw and may be varied, for example in any part of the screw.

The screw of the present invention is mainly used for a container conveying device, but a screw in which a rod is spirally wound with a wire can also be used for conveying powder particles. Conventionally, one of the transportation methods is to insert and arrange a coiled wire, which is mostly made of steel, into a metal or resin tube, rotate the steel wire, and insert powder particles from an input port provided at one end of the tube. There is a method of transporting the body to the discharge port provided at the other end, and the screw of the present invention may be used instead of the steel wire. However, the powdery particles here are so-called bulk materials such as gravel, crushed stone, coal, coke, iron ore, soil, limestone, grain, cement, chips and pellets of wood and resin.

[0025]

EXAMPLES The flexible screw of the present invention will be described below in detail based on examples. FIG. 1 shows an example of a screw, and FIG. 2 shows a cross section thereof. This screw is composed of a flexible rod 10 and a polymer-coated wire 20 that is spirally wound around the rod 10. The rod 10 is provided with a resin layer 12 on a steel rope 11, and the wire 20 has a core body 21 made of a fiber bundle at the center of a polymer coating layer 22. Example 1 A wire rod having a buckling rate of 0.05% was prepared according to the method described above using Kevlar fiber bundles as the core of the wire and Lübmer as the polymer coating material. A flexible rod having a resin layer made of Cefralsoft (manufactured by Central Glass Co., Ltd., soft fluororesin) on a steel rope is spirally wound at a winding pitch of 35 mm on a flexible rod to be flexible as shown in FIG. A screw was made. This screw has a rod diameter of 7.0 m.
m, diameter of steel rope 6.0 mm, wall thickness of resin layer of rod 1.0
mm, the flight diameter of the screw was 13 mm. Example 2 A flexible screw was produced in the same manner as in Example 1 except that a wire rod having a core body buckling rate of 0.01% was used. Comparative Examples 1 and 2 A flexible screw was produced in the same manner as in Example 1 except that wire rods having a buckling rate of the cores of 3% (Comparative Example 1) and 1% (Comparative Example 2) were used.

Using the thus obtained flexible screws of Examples and Comparative Examples, the following tests were conducted. In a loop-shaped container transport path that includes four bends that bend at 90 degrees with a radius of curvature of 650 mm, and has a screw length of 16 m, the screw rotation speed is 800 rpm, the container transport speed is 28 m / min, the container transport pitch is 105 mm, and the container weight is 200 g. The container was transported at room temperature.
When continuous operation was performed to examine whether or not the winding pitch of the wire rod was disturbed, the screw of Comparative Example 1 showed that on the second day,
In the screw of Comparative Example 2, pitch disorder was observed on the 15th day, whereas in the screws of Examples 1 and 2, no change in the winding pitch was observed thereafter.

[0027]

As described above, the flexible screw of the present invention has a buckling rate of 0.3% or less of the core body in the wire rod spirally wound on the flexible rod. Even if there is a large change, or even if pressure is applied by the conveyance of a large-capacity container, the winding pitch of the wire does not easily change, and pitch irregularity can be prevented.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an example of a flexible screw of the present invention.

FIG. 2 is a cross-sectional view of the flexible screw shown in FIG.

FIG. 3 is a vertical cross-sectional view for explaining the principle of manufacturing a wire rod.

[Explanation of symbols]

 10: Flexible rod 11: Steel rope 12: Resin layer of rod 20: Polymer coated wire 21: Core body 22: Polymer coated layer

Claims (1)

(57) [Claims] 1. A polymer-coated wire having a core made of fiber bundles having a buckling ratio of 0.3% or less is spirally wound on a flexible rod having a resin layer provided on a steel rope. Characteristic flexible screw for conveyor.