JP3025371B2 - Flexible screw - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the transport of containers such as glass, plastic bottles, aluminum bottles, cans, and the like (hereinafter, also referred to simply as "containers") in which fillers such as liquids and solids are filled. Also, the present invention relates to a flexible screw used in a transport device suitable for transporting so-called loose particles.

[0002]

2. Description of the Related Art The present inventors have proposed a flexible screw having a resin cord spirally provided on a flexible rod [“Flexible screw and a transport device using the same” (International Publication number WO91 /
06493) has already been disclosed, and it has been shown that this makes it possible to smoothly carry the container even on a curved route and to reduce the maintenance cost of the screw for the operation of the apparatus.

In a container conveying device using the screw, the neck of the container is pushed by the helical rotation of the cord to advance the container. Is transported. Therefore, when the screw is operated, a force for changing the winding pitch always acts on the spirally wound cord. If the pitch of the cord changes due to this force, problems such as the inability to smoothly transport the container and the inconsistency in the transfer amount of the granular material occur.

As a method of preventing a change in the pitch of the cord, a method of fixing the resin cord by bonding or fusing the rod to the rod can be considered. However, according to this method, the cord and the rod are integrated. It was found that the flexibility of the screw was significantly impaired.

Accordingly, it is an object of the present invention to provide a flexible screw which does not fix a resin cord to a rod and does not cause a change in cord pitch.

[0006]

SUMMARY OF THE INVENTION The present invention is a flexible screw having a flexible rod and a resin cord spirally provided on the rod, wherein the resin cord has a springback rate of 1%. % Or less.

The springback ratio in the present invention is
It is defined as follows: That is, in the present invention, a resin cord is spirally wound on a flexible rod and fixed on the flexible rod at both ends of the screw to form a flexible screw. In the above, when the resin cord is cut at any two points separated by an appropriate distance (for example, 2 m or more) and the cord is released from the fixed state, the spiral cord is formed by a residual reaction force (stress) when the cord is wound. As a result, the outer diameter of the screw increases. In the present invention, this phenomenon is referred to as springback, and the springback ratio is expressed as a percentage of the ratio of the increase in the screw diameter due to the springback to the screw diameter before cutting. And is represented by the following equation.

[0008]

(Equation 1)

(Where D is the diameter of the screw before cutting the cord, and D 'is the diameter of the screw after cutting.)

The springback rate represented by the above equation is 1
% Or less, preferably 0.5% or less, the pitch of the cord is hardly disturbed by the load applied during the transfer of the container or the like, and smooth transfer can be achieved.

In order to obtain a flexible screw having a springback rate of 1% or less, for example, when a resin cord is spirally wound around a flexible rod, the cord is twisted while being twisted in a direction opposite to the twist. It is preferable to perform spiral winding (this is referred to as winding with twisting), and then to perform annealing. In the case where the cord is wound with a twist as described above, if the cord tries to loosen due to residual stress at the time of winding, a force acts in a direction approaching the rod, resulting in a flexible screw having a small springback rate. It is.

The resin material of the resin cord used in the present invention may be, for example, a polyolefin [for example, various polyethylenes, especially ultra-high molecular weight polyethylenes or those based on them and having improved injection moldability (for example, commercially available products include , Polypropylene, etc.), polyethers (eg, polyacetal, polyphenylene ether, etc.), polyamides (eg, 6-nylon, 6,6 nylon, 11-nylon, etc.), fluororesins (eg, polytetrahedral) Examples thereof include fluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and polyesters (eg, polyethylene terephthalate, polybutylene terephthalate, and the like). Among these resins, lubricants are preferably used because they are excellent in properties required as a cord material of a flexible screw, such as abrasion resistance, rolling properties, and slip properties.

The cord may be entirely made of the above resin,
It may have a core made of a fiber bundle of Kevlar (aramid fiber), glass, carbon fiber, or the like. A cord having a core body is advantageous in that cord elongation due to a temperature rise due to frictional heat and a load applied during container transportation can be suppressed, and consequently a helically wound cord pitch can be prevented from being disordered.

The winding pitch of the cord to be spirally wound on the flexible rod depends on the size of the container, the number of containers to be conveyed, the number of screw rotations, etc., in consideration of the speed of conveying the containers in the container conveying device. Based on the type and size of the granular material in the granular material transporting apparatus, it is appropriately determined. Also, the pitch need not be constant over the entire length of the screw, but may vary, for example, at any portion of the screw.

As the flexible rod in the present invention, any of the rods disclosed in the aforementioned International Publication No. WO 91/06493 can be used. In a preferred example, a metal cable is coated with a resin or the like. Flexible rod is illustrated.

The metal cable has a structure in which several or several tens of strands of metal such as steel, nickel, cobalt and their alloys are twisted and further several strands are twisted. Is preferably used.

The resin material constituting the coating layer on the metal cable is not particularly limited, but is preferably a resin having excellent abrasion resistance and low contact resistance because it is in direct contact with the container and slides at high speed. . Examples of such resins include polyalkylenes (for example, the above-described lubromer (manufactured by Mitsui Petrochemical Industries, Ltd.), polypropylene and the like), polyethers (for example, polyacetal, polyphenylene ether, and the like),
Polyamide (for example, 6-nylon, 6,6 nylon, 1
1-nylon, etc.) and polyamide elastomers (for example, commercially available products manufactured by Ube Industries, PAE1)
200), thermoplastic urethane (for example, as a commercial product,
Kuraray Co., Ltd., trade name: Kuramilon 9198), thermoplastic polyesters (for example, commercially available products, Perprene S1001-04, manufactured by Toyobo Co., Ltd.), and soft fluororesins

Here, the soft fluororesin is obtained by grafting a fluororesin onto a fluororubber, a thermoplastic fluoroelastomer comprising a fluororesin as a hard segment and a fluoroelastomer (rubber) as a soft segment, and a fluorocopolymer. For example, a vinylidene fluoride-hexafluoropropylene copolymer or a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer having a fluororubber main chain and grafted with vinylidene fluoride (as a commercial product, Central Glass Co., Ltd., trade name Sefralsoft 150),
Vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer (molar ratio 50:30:20)
A thermoplastic fluoroelastomer comprising 85% by weight of a soft segment and 15% by weight of a hard segment of an ethylene-tetrafluoroethylene-hexafluoropropylene copolymer (molar ratio 43: 49: 8) (a commercially available product is Daikin Industries, Ltd.) Manufactured by Daicel Thermoplastic T-530), ethylene tetrafluoride-propylene copolymer, ethylene tetrafluoride-ethylene copolymer, and the like.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a flexible screw of the present invention will be described in detail based on embodiments. In a flexible screw 10 shown in FIG. 1, a resin cord 12 is spirally wound around a flexible rod 11 at a constant pitch. The flexible rod 11 is formed by coating a metal cable with a resin. Although not shown in the drawings, the resin cord 12 is fixed to the flexible rod 11 at both ends of the screw.

EXAMPLE 1 A steel rod is used as a metal cable, and a flexible rod 11 is formed by using Sefralsoft 150 (described above) as a resin material for covering the steel cable, and a core made of a Kevlar (described above) fiber bundle is formed on the rod. Was helically wound so as to have a winding pitch of 35 mm with twisting to produce a flexible screw 10 having a springback rate of 0.05%. In addition, at both ends of the screw,
The cord was fixed on the rod by removing the lubricating layer of the cord and winding the Kevlar core in a state of being exposed, and then applying an adhesive thereto. The screw had a rod diameter of 7.0 mm, a cord diameter of 4.5 mm, and a screw diameter of 16.0 mm.

Example 2 A flexible screw having a springback rate of 0.5% was produced in the same manner as in Example 1 except that nylon was used as the resin material of the resin cord.

Comparative Example 1 A flexible screw having a springback rate of 2% was obtained in the same manner as in Example 1 except that cefural soft 150 was used as the resin material of the resin cord, and the spiral winding of the cord was performed without twisting. Was.

Comparative Example 2 A flexible screw having a springback rate of 5% was produced in the same manner as in Example 1 except that nylon was used as the resin material of the resin cord and the cord was wound spirally without twisting. .

[0024]

Test Example Next, the flexible screws obtained in each of the above Examples and Comparative Examples were examined for any change in the pitch of the cords when the screws were operated at a rotation speed of 1000 rpm in the container conveying device. . Prepare 10 screws for each, and after 12 hours of operation
We decided to count the number of pitch changes that were observed in some places. The container transported at this time was a polyethylene terephthalate container having a capacity of 1.5 liters, and the weight was 6 kg.
It was 0 g. As a result, the number of screws in the example was 0, the number of screws in the comparative example 1 was 2, and the number of screws in the comparative example 2 was 7.

[0025]

As described above, in the container conveying apparatus using the flexible screw of the present invention, the pitch of the cord does not change due to the force acting on the cord when the screw is operated, and the container can be smoothly transported. Become.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a flexible screw of the present invention.

[Explanation of symbols]

 10 Flexible screw 11 Flexible rod 12 Resin cord

Claims (1)

(57) [Claims] 1. A flexible screw comprising a flexible rod and a resin cord spirally provided on the rod, wherein the resin cord has a springback rate of 1%.
A flexible screw characterized by the following.