JPS5912176Y2 - Heat shrink tube manufacturing equipment - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an apparatus for manufacturing a heat-shrinkable tube.

A heat-shrinkable tube is a hollow tube that is made by extruding an organic polymer material and then heating and stretching it.The tube is inserted into the object to be packaged and heated to a temperature above the softening point of the tube material. When heated to a certain temperature, the diameter of the tube shrinks according to the stretching ratio of the stretching process, so that the object can be wrapped.

As a device that continuously manufactures this heat-shrinkable tube,
Although not shown, the material tube is guided into a heated hollow cylindrical tube while injecting pressure gas into the material tube, and the material tube is heated between the internal pressure caused by the pressure gas and the heat received from the pre-shaped tube. An apparatus is known in which the material tube is expanded until it touches the inner wall of a certain shaped tube, subjected to a stretching process, and then the expanded material tube is cooled and taken off as a product.

In such a conventional device, the material tube expands until it touches the inner wall of the cylindrical tube while the internal pressure is applied, and in this state, the material tube is pulled out by applying a tensile force to the end in the axial direction. When this happens, a large frictional force acts between the surface of the material tube and the inner wall of the tube, causing the material tube to stretch in the axial direction.

In addition, in order to compensate for the drawbacks, a technology has been considered that controls the surface of the material tube to the extent that it does not come in contact with the inner wall of the pipe when heating and expanding the material tube, but this technology results in poor dimensional accuracy of the product. Moreover, if there is variation in the thickness of the material tube, the thin part will bulge out excessively, which may cause a rupture or create a tube with uneven thickness.

The object of this invention is to provide a novel heat-shrinkable tube manufacturing apparatus that eliminates the above-mentioned drawbacks.

An embodiment of this invention will be described in detail below with reference to the drawings.

In Fig. 1, reference numeral 1 denotes a delivery bobbin in which a material tube To made of a material such as polyethylene is wound and stored, and even during rotation of the delivery bobbin, there is no flow from the end of the material tube To into the tube. The inside of the body of the delivery bobbin 1 is connected in communication with a pressure gas supply pipe 11 via a rotary joint 12, for example, so that the pressure gas can be injected.

Reference numeral 2 denotes a chain that runs in circulation, and a pair of shaped pipe units 2A and 2B are attached to each piece or equally spaced pieces of this chain 2 so as to be closely continuous with each other in the longitudinal direction. .

The pipe units 2A and 2B have the shape of a hollow cylinder divided into two by a plane including its central axis, and are attached to the chain 2 via a rotation shaft 22 so as to be openable and closable, and are normally operated by a spring 21 as shown in FIG. As shown in Fig. 3, they are suspended in an open state, but if these cylindrical tube units 2A and 2B are pressed from both sides, they will be closed as shown in Fig. 3, completely emptying one hollow cylinder. There is.

Opening/closing guide plates 3A and 3B are arranged along the running path of the chain 2.

As shown in Figure 1, they open in an eight-shape toward the upstream side of the travel, and are gradually arranged in parallel at intervals of a constant width, but this width is determined by the guide as shown in Figure 3. The distance between the inner walls of the plates is set to be exactly equal to the outer diameter of the closed tube units 2A and 2B.

Therefore, in the parallel sections of the opening/closing guide plates 3A and 3B, the oval tube units 2A and 2A attached to the chain 2,
2B is a hollow cylindrical substantially continuous pipe 5 sectioned.

Below this certain shaped pipe 5 are hot air blowing pipes 41 in order from the upstream side.
, and a cold air blowing pipe 42 are disposed, so that the preheating pipe 5 is divided into three regions, a preheating region 51, a heating region 52, and a cooling region 53, in order from the upstream.

The material tube TO described above is arranged so as to run along the center axis of this preformed tube 5, and a pressure roller 6 and a winding bobbin 7 are arranged downstream.

Next, the operation of this invented device will be explained.

As the chain 2 runs, a certain shaped pipe unit} 2A, 2
When B approaches the opening/closing guide plates 3A, 3B, the cylindrical tube units 2A, 2B begin to close one after another, and in the section where the opening/closing guide plates 3A, 3B are parallel, a completely hollow cylindrical cylindrical tube 5 is formed. Intimidate.

The raw material tube To sent out from the delivery bobbin 1 enters the inside of the guide tube units 2A and 2B when they are in the open state, is sandwiched between the guide tube units 2A and 2B and is pulled, and is transferred to the guide tube 5. Travels along the center axis.

Inside the certain-shaped tube 5, especially in the preheating area 51 and hot forming area 52 in the first half, the raw material tube To is first heated by receiving hot air from the hot air blowing pipe 41, and the pressure of the pressure gas compressed into the tube is increased. As a result, the shaped tube 5 expands to the full extent of the inner wall to become a product tube T, and then cooled in the cooling area 5.
2, it is cooled and fixed by receiving cold air from the cold air blowing pipe 42.

As Chain 2 progresses, Kaigata Pipe Units 2A, 2
When B is removed from the opening/closing guide plates 3A and 3B, the spring 21
It opens on both sides by the action of , and separates from the outer periphery of the product tube T, which has already expanded to the full extent of the inner wall of the shaped tube 5.

On the other hand, the product tube T advances as it is, is flattened by the pressure roller 6, and then wound onto the winding bobbin 7.

As detailed above, according to this invention, (i) the product tube advances integrally with the expanded product tube, so there is no problem of the product tube being pulled and elongated; (11) the product tube is Since it expands to the full inner diameter of the shaped tube and is fixed, its dimensional accuracy is good.(Since the 11D shaped tube unit is individually separated from the outer circumference of the product tube in the radial direction, it is easy to separate the shaped tube and the product tube.) There are effects such as.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of this invention, and FIGS. 2 and 3 are lines II-II and III-I in FIG. 1, respectively.
FIG. 4 is a sectional view taken along line II, and a side view of a certain shaped tube section with the front opening/closing guide plate removed. DESCRIPTION OF SYMBOLS 1... Delivery bobbin, 11... Pressure gas supply pipe, 2... Chain, 2A, 2B... Command pipe unit, 3A, 3B... Opening/closing guide plate, 41... Hot air blowing Pipe, 42... Cold air blowing pipe, 5... Hollow shaped pipe.

Claims (1)

[Scope of utility model registration request] A plurality of openable and closable hollow cylindrical shaped pipe units 2A, 2B installed in continuous proximity in the longitudinal direction of the chain 2 running in circulation, and the shaped pipe units arranged along the running path of the chain. opening/closing guide plates 3A and 3B that close the tube 5 to form the preformed tube 5; a heating device 41 and a cooling device 42 disposed along the longitudinal direction of the preformed tube 5; and a device for injecting and feeding gas through the certain shaped tube.