JPS5856510B2 - Method of forming a coating layer with varying thickness on the surface of the core - Google Patents

Description

Detailed Description of the Invention The present invention uses, for example, a fiber rope or strand as the core, and the surface of the core is made of rubber, synthetic resin, or a foam thereof, and the thickness thereof varies. It relates to a method for manufacturing a rope-like article whose thickness changes continuously by forming a coating layer, and the rope-like article obtained by the present invention can be used for handrail ropes, decorative ropes, fishing float nets, etc. It is suitable for applications such as.

Conventionally, when producing this kind of rope-like product, the method of forming a coating layer of varying thickness on the surface of the core was to move the core 1 into the crosshead 2 of an extruder, as shown in FIG. When passing the tension change device 3 behind the crosshead 2.
The moving speed of the core body 1 is changed by the tension changing device 3, and as a result, the rubber or synthetic resin discharged in a constant amount from the die 4 at the tip of the crosshead 2 forms a thick layer on the surface of the core body 1. It was designed to form a coating layer whose thickness changes.

This tension changing device 3 has various types, and one example will be explained with reference to FIG.
and 5', the rod 1 has its upper end brought into contact with a rotary cam plate 6 so as to move up and down.

This tensioning device 3 intermittently applies tension to the moving core 1 by moving the rod 7 up and down, which is taken up by a pulling machine (not shown) in front of the crosshead 2. This changes the moving speed of the body 1.

As described above, the method of forming a coating layer whose thickness changes on the surface of the core body 1 by changing the moving speed of the core body 1 using the tension changing device 3 is as follows: The degree to which the speed of the core body 1 is reduced,
The difference is the degree to which speed increases when the tension is relaxed.

That is, when tension is applied to the core 1, the core 1 stretches, and the extent to which the core decelerates is reduced by that stretch.On the other hand, when the tension is released, the aforementioned elongation rapidly recovers. Therefore, the speed increases rapidly.

Therefore, as shown in FIG. 2, the change in the thickness of the coating layer 8 formed on the surface of the core 1 is gentle on one slope 8a and steep on the other slope 8b.

This change in the thickness of the coating layer 8 was not aesthetically pleasing because its shape was not symmetrical.

Furthermore, if the fiber materials and amounts of the ropes or strands used in the core body 1 differ, their elongation will vary, making it difficult to change the thickness of the coating layer 8 into a constant shape.

The present invention was invented based on the above-mentioned circumstances, and provides a method for forming a coating layer on the surface of a core that has a stable shape and a variable thickness that is aesthetically pleasing. .

The following description will be made with reference to embodiments of the present invention. In FIG. 3, 1 is a core body.

This core 1 is pulled out from the winding bobbin 9 by a take-up machine (not shown) provided on the right side and moved at a constant speed.

Reference numeral 10 denotes a crosshead of the extruder, through which the core 1 passes.

The crosshead 10 includes a head body 13 having a through hole 11 in the center and a supply hole 12 for molten resin supplied from a cylinder (not shown) of an extruder, and a through hole in the head body 13. 11 and has a through hole 14 in the center thereof, and a die 16 fixed to the tip of the head body 13.

A control member 18 connected to a drive device 1T is inserted into the mandrel 15 of the crosshead 10 into the through hole 14 so as to periodically move in and out from the front and back from its tip.

To explain in more detail, the control member 18 includes a tubular part 20 provided with a core guide hole 19 in the center for introducing the core 1 from the rear, and a cylindrical tip attached to the tip of the tubular part 20. 21, which is periodically slid back and forth along the through-hole 14 of the mandrel 15 by a driving device, so that the cylindrical tip 21 protrudes and retracts from the tip of the mandrel 15. .

In the present invention, when the core body 1 is passed through the crosshead 10 at a constant speed, the control member 18 periodically appears and retracts from the tip of the mandrel 15 within the crosshead 10, thereby changing the volume of the molten resin passage. Therefore, the molten resin flowing through this portion is discharged from the tip of the die 16 while changing as the control member 18 slides.

That is, when the control member 18 protrudes from the tip of the mandrel 15, a large amount of molten resin is discharged from the tip of the die 16, and when the control member 18 is recessed, only a small amount of molten resin is discharged.

Therefore, the coating layer 8 formed on the surface of the core body 1 is formed with varying thickness.

Incidentally, the structure of the crosshead may be as shown in FIG. 4.

That is, the mandrel 15 is fitted with the head body 1 and the through hole 11' of the head body 13', and has a core guide hole 19' in the center thereof for introducing the core 1 from the rear. ', and a die 16' fixed to the tip of the head body 13', and inner herots 22 (control members) of the die 16' are provided so as to protrude and retract from the side wall of the die 16' at several appropriate locations. It is what it is.

Note that this rod 22 is, for example, a sliding member 2 provided so as to slide back and forth on the outer periphery of the die 16' as shown in the figure.
The protrusion 25 protruding from the rod 22 is engaged with the inclined surface 24 of No. 3, and the sliding member 23 is connected to the drive device (not shown -0
By sliding the outer periphery of the die 16' back and forth, the protrusion 25 of the rod 22 is moved along the inclined surface 24 of the sliding member 23, thereby moving the rod 22 toward the die 16'.
The rod is made to reciprocate up and down in a rod hole 26 provided in the rod hole 26.

In this way, the present invention forms a coating layer of varying thickness on the surface of the core by changing the amount of rubber or synthetic resin discharged from the tip of the die without changing the tension of the core. Therefore, unlike conventional methods, there is no effect of the elongation of the core, and a coating layer with a variable thickness that has a stable shape and is aesthetically pleasing can be formed on the surface of the core.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional method. FIG. 2 is a longitudinal sectional view of a rope-like article obtained by a conventional method, and FIG. 3 is a diagram showing an embodiment of the present invention. FIG. 4 is a diagram showing another embodiment. 1...
Core body, 8...Coating layer, 10...Cross head, 13, 13'... Head body, 15
, 15'... Mandrel, 16, 16'...
...Tie, 18...Control member, 22...
...Rod (control member).

Claims (1)

[Claims] 1 In a method of forming a coating layer of rubber or synthetic resin on the surface of a core by extrusion molding, the core is passed through the crosshead of an extruder at a constant speed, and the main body and mandrel in the crosshead are A control member is moved in and out of the molten resin passage formed by the die at a predetermined period, and by making the control member protrude into the molten resin passage, the amount of molten resin discharged from the tip of the die is increased, and by being submerged, the amount of molten resin is discharged. 1. A method for forming a coating layer of varying thickness on the surface of a core, the method comprising reducing the amount of molten resin and periodically changing the amount of molten resin discharged.