JPH0363943B2 - - Google Patents

Description

[Detailed Description of the Invention] [Background and Objectives of the Invention] The present invention relates to a continuous manufacturing apparatus for heat-shrinkable resin tubes, which expands a resin tube material (original tube) of a heat-shrinkable resin tube, generally called a heat-shrink tube, in the radial direction. It is about improvement.

The blowing line that manufactures heat-shrinkable resin pipes expands resin pipe material (hereinafter referred to as raw resin pipe) only in the radial direction without stretching it in the axial direction.In general, the radial direction is approximately 150 to 300% The axial tolerance is within ±5%.

This is because if it stretches in the axial direction to the same extent as in the radial direction, it will shrink in both the radial and axial directions during the heat shrinking operation during use.

In this blowing line, it is necessary to heat the raw resin tube before expansion to a temperature above its softening point and below its melting point.

At a temperature suitable for this expansion molding, the base resin becomes soft to a jelly state.

In a continuous production blowing line, it is necessary to feed the jelly-like raw resin tube continuously to the expansion molding section without stretching it.

FIG. 3 is an explanatory diagram of a conventional continuous manufacturing apparatus for heat-shrinkable resin pipes.

In the figure, 1 is a delivery bobbin, 2 is a delivery device 3 is a low tension dancer, 4 is a heating layer, 5 is a liquid heating medium, 6 is a raw resin pipe, and 7 is a guide pulley.

Further, 8 is a delivery drive motor, 9 is a heating layer heater, 10 is a molding section, 11 is a cooling water tank, 12 is an air wiper, 13 is a take-up machine, 14 is a take-off drive motor, and 15 is a speed setting device.

Then, the feed bobbin 1 on which the raw resin tube 6 is wound is driven by a forced drive feeder 22 driven by the feed drive motor 8, and a low tension dancer 3
It is sent to the heating tank 4 via .

After being heated to an appropriate molding temperature by the heating medium 5 in the heating tank 4, it is sent to the molding section 10 and formed into a heat-shrinkable resin tube, and then taken to the take-up device 13 via the cooling water tank 11 and the air wiper 12.

The delivery drive motor 8 and the take-up drive motor 14 are
The speed setter 15 synchronizes the resin tube speeds so that they are the same, and the integral error of the resin tubes becomes a displacement signal of the low tension dancer 3 and is fed back to the delivery drive motor 8 for correction.

In the above structure, when trying to make the tension of the raw resin tube 6 in the delivery dancer part extremely low, there is a winding tension of the raw resin pipe 6 on the delivery bobbin 1, and below this winding tension, the delivery bobbin Even when the tube 1 rotates, the raw resin tube 6 does not come undone.

Further, in the heating tank 4, there is viscous resistance when running through the liquid of the heating medium 5, and if the heating tank 4 is long, a considerably large tension is generated.

On the other hand, in order to keep the molding temperature of the raw resin tube 6 precisely constant, the temperature of the heating medium 5 is controlled to the same temperature as the appropriate molding temperature, so the required heating time becomes longer, and in order to increase the manufacturing speed. In this case, the heating tank 4 also becomes longer.

The heating time varies depending on the size and material, but at least 30 seconds or more is required, so a heating tank 4 of 2.5 m or more for a linear speed of 5 m/min and 5 m or more for a linear speed of 10 m/min.
This requires a longer distance to travel in the liquid and greater viscous resistance.

This tension needs to be extremely low as it is affected by the weight of the raw resin tube 6. FIG. 4 is a reference example in which the horizontal axis represents tension and the vertical axis represents elongation, and shows the relationship between elongation and tension when the raw resin tube 6 is heated.

According to FIG. 4, in order to keep the elongation within 5%, the tension must be 5 g or less, and with the conventional structure described above, it is difficult to satisfy this elongation within practical tolerances.

The present invention has been made in view of the above circumstances, and is a method for continuous production of heat-shrinkable resin pipes that can significantly reduce the axial elongation of the raw resin pipe, expand in the radial direction, and produce high-precision heat-shrinkable resin pipes. The purpose is to provide equipment.

[Summary of the Invention] The continuous manufacturing apparatus for heat-shrinkable resin pipes of the present invention includes a heating tank that heats a raw resin pipe fed through a guide pulley pulled out from a delivery bobbin with a heating liquid, and a heat-shrinkable resin pipe that is heated in the heating tank. a molding section that expands the raw resin pipe into a resin pipe after the raw resin pipe is removed; and a take-up device configured to wind up the expanded resin pipe through a cooling water tank; installed between a delivery capstan for pulling out a pipe, and the delivery capstan and the guide pulley;
The non-contact dancer position detector detects slack in the raw resin pipe, and the raw resin pipe fed through the guide pulley is heated by jet-flowing the heating liquid, which has a higher specific gravity than the raw resin pipe, in the inclined groove. At the same time, a signal indicating the slack state of the raw resin pipe detected by the heating tank configured to run and the non-contact dancer position detector is sent, and the speeds of the take-up drive motor and the delivery capstan drive motor are synchronized. The apparatus is provided with a speed setting device for adjustment, and a flow control valve for controlling the speed at which the heated liquid is jet-flowed into the inclined groove so as to substantially correspond to the traveling speed of the raw resin pipe.

[Example] The continuous manufacturing apparatus for heat-shrinkable resin pipes of the present invention will be described below with reference to Examples and FIGS. 1 and 2, in which the same parts as in the prior art are denoted by the same reference numerals.

FIG. 1 is an explanatory diagram, and FIG. 2 is a sectional view taken along the - arrow in FIG. 1.

In the figure, 16 is a delivery capstan, 17 is a delivery capstan drive motor, 18 is a heating tank heater that heats the heating liquid (polyethylene glycol) 31 in the heating tank 4, 19 is a storage tank, 2
0 is a signal converter, 21 is a storage tank heater, and 22 is a flow set adjustment valve.

Also, 23 is a filter, 24 is a circulation pump,
25 is a flow control valve, 26 is an electro-pneumatic converter, 27 is a speed setting device, 28 is a non-contact dancer position detector, 29 is a guide pulley drive motor, 3
0 is a heated liquid jet flow nozzle, and 32 is an inclined groove with a V-shaped cross section.

The delivery bobbin 1 is attached to the delivery machine 2 and is formed to be freely rotatable.

The raw resin pipe 6 passes through a delivery capstan 16 driven by a delivery capstan drive motor 17 pulled out from the delivery bobbin 1, and constitutes a dancer section with an appropriate slack between it and the guide pulley 7.

Raw resin pipe 6 sent out from guide pulley 7
The detailed cross-section provided in the heating tank 4 is shown in FIG. 2, which shows that it passes through an inclined groove 32, passes through a molding section 10, passes through a cooling water tank 11, an air wiper 12, and is taken up by a take-up machine 13. .

Although a detailed description of the molding section 12 is omitted, the original resin tube 6 is expanded only in the radial direction, and maintains its shape even after leaving the take-off machine 13.

The heating tank 4 contains a heating liquid 31 of polyethylene glycol as a heating medium, and is controlled to a constant appropriate molding temperature by a heating tank heater 18.

The lower part of the heating tank 4 is connected to a storage tank by piping, and the inside of the storage tank 19 is also filled with heating liquid 3.
1 is heated to an appropriate molding temperature by a storage tank heater 21.

The heating liquid 31 is driven by the circulation pump 24 from the storage tank 19 via the filter 23, and part of it returns to the heating tank 4 via the flow set adjustment valve 22, and the other part passes through the flow control valve 25 and returns to the heating tank 4. The air is blown out to the upper part of the inclined groove 32 via the etf flow nozzle 30.

The running speed of the raw resin pipe 6 is set by a speed setting device 27, which includes a delivery capstan drive motor 17, a take-up drive motor 15, and a guide pulley drive motor 29.
and is connected so that its tuning signal is sent via an electro-pneumatic converter 26 to a flow control valve 25 that controls the heating medium jet flow rate.

Note that the flow set adjustment valve 22 is a bypass valve that adjusts the initial jet flow.

The speed of the raw resin tube 6 in each section is controlled based on the drawing machine 13 so that it is the same, but since an integral error with respect to the drawing speed appears as a slack displacement of the non-contact dancer position detector 28, The signal from the non-contact dancer position detector 28 is subjected to feedback correction by the signal converter 20 so that the speed is always synchronized with the take-up speed.

Now, even if the resin tube 6 being delivered from the delivery bobbin 1 is under considerable tension, the tension is cut off by the pinch roller type delivery capstan 16, and there is a gentle slack between the delivery capstan 16 and the guide pulley 7. It is only the dead weight of the resin pipe 6.

Then, it is gently fed into the inclined groove 32 in the heating tank 4 at the same running speed as the guide pulley 7, and is heated and floated by the heating liquid 31 spouted from the heating liquid jet flow nozzle 30, while the outer diameter
The 2.5 mm raw resin tube 6 runs while being heated under an extremely low tension of 5 g or less.

The dead weight of the slack in the non-contact dancer section is canceled by the jet flow that is blown out at the same speed as the speed at which the raw resin pipe is driven by the heated liquid 31 jetted out by the heated liquid jet flow nozzle 30. It's summery. The heating liquid 31 is polyethylene glycol with a specific gravity of about 1, and the resin pipe 6
As shown in FIG. 2, the raw resin tube 6 floats and advances in the heating liquid 31 of the medium in the inclined groove 32.

It is not preferable to use a pipe as the inclined groove 32 because the raw resin pipe 6 will rub against the inner surface of the pipe.

Although the upper surface of the raw resin pipe 6 is not shown because it is exposed, in reality, a heating medium of the same temperature can be applied from the upper part like a shower.

Incidentally, if the inclined groove 32 is not provided in the heating tank 4 as in this embodiment, the jet flow will flow through the entire large heating tank, making it difficult to match the flow velocity with the velocity of the raw resin tube 6.

Further, since the inclined groove 32 is inclined, the flow can be rectified and maintained at the same speed up to the end of the tank without stagnation.

The tension applied to the six turns of the original resin tube on the delivery bobbin 1 is interrupted by a forced delivery capstan 16 provided between the delivery bobbin 1 and the dancer.

In this way, the continuous heat-shrinkable resin tube manufacturing apparatus of this embodiment is equipped with an extremely low-tension non-contact dancer section that is not affected by the wrapping tension of the raw resin tube on the delivery bobbin, and from which the raw resin tube is rolled in the heating tank. When running,
The heating liquid is jet-flowed in the inclined groove at almost the same speed as the raw resin pipe, thereby heating the raw resin pipe and running at the same time, minimizing the running tension while heating the raw resin pipe. As a result, axial elongation can be minimized.

Therefore, the jelly-like heated raw resin tube can be continuously fed to the molding section where it is expanded only in the radial direction with the elongation in the axial direction within 5%, making it possible to produce high-precision heat-shrinkable resin tubes. Can be manufactured.

In addition, it is possible to provide a blowing line that enables economical mass production at high speeds that cannot be obtained with batch-type (casting) or tape-wrap (a method in which the tape is wrapped in tape and run).

In the above embodiment, the case where there is one raw resin pipe has been described, but it is also possible to apply a plurality of raw resin pipes, and depending on the desired tension, the driving of the guide pulley 7 may be omitted.

[Effects of the Invention] As described above, according to the continuous manufacturing apparatus for heat-shrinkable resin pipes of the present invention, the elongation in the axial direction of the raw resin pipe can be significantly reduced and the elongation in the radial direction can be expanded, and a high-precision heat-shrinkable resin pipe can be produced. This has the effect of making it possible to produce.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the continuous heat-shrinkable resin pipe manufacturing apparatus of the present invention, FIG. 2 is an enlarged cross-sectional view taken in the direction of the - arrow in FIG. The explanatory diagram, FIG. 4, is an explanatory diagram of the relationship between tension and elongation of the raw resin pipe. 1... Delivery bobbin, 4... Heating tank, 6... Original resin pipe, 7... Guide pulley, 10... Molding section, 1
DESCRIPTION OF SYMBOLS 1... Cooling water tank, 13... Taking machine, 14... Taking drive motor, 16... Delivery capstan, 17...
... Delivery capstan drive motor, 25 ... Flow control valve, 27 ... Speed setting device, 28
... Non-contact dancer position detection device, 31 ... Heating liquid, 32 ... Inclined groove.

Claims (1)

[Scope of Claims] 1. A heating tank that heats a raw resin tube drawn out from a delivery bobbin and sent through a guide pulley with a heating liquid, and an expansion from the raw resin tube heated in the heating tank to a resin tube. and a take-up device formed to wind up the expanded resin pipe through a cooling water tank, between the delivery capstan and the guide pulley that pull out the raw resin pipe from the delivery bobbin. A non-contact dancer position detector is provided to detect slack in the raw resin pipe, and the heated liquid having a higher specific gravity than the raw resin pipe is jet-flowed through the raw resin pipe fed through the guide pulley in an inclined premises. At the same time, a signal of the slack state of the raw resin pipe detected by the heating tank formed to run and the non-contact extra dancer position detector is sent, and the signal is sent to the take-up drive motor and the delivery capstan drive motor. and a flow control valve that controls the speed at which the heated liquid is jet-flowed into the inclined groove so as to substantially correspond to the running speed of the raw resin pipe. Continuous manufacturing equipment for heat-shrinkable resin pipes. 2. The continuous heat-shrinkable resin pipe manufacturing apparatus according to claim 1, further comprising a guide pulley drive motor that drives the guide pulley and is driven in synchronization with the speed of the delivery capstan drive motor.