JPS5912811A - Tube expander - Google Patents

Abstract

PURPOSE:To obtain a tube expander that can provide an intended thermo shrinkable tube efficiently by expanding the diameter of a resin tube made of a specified expandable hollow body having tree or more fin parts that are folded in the longitudinal direction. CONSTITUTION:The tube expander 10 that is made from plastic (or rubber) material (such as polyester) and provided with 3-12 fin parts 1 folded along longitudinal direction. Using the above-mentioned tube expander 10; (1) the tube expander 10 that has been sealed in advance at one end is inserted into the blank tube 2 heated up to the intended temperature, then, (2) compressed air is supplied from the other end of the tube expander 10 to give the tube expander 10 internal pressure and to expand the tube expander 10 in order of 10', 10'', 10''' and then, (3) the blank tube 2 is expanded with the tube expander up to the intended step. Thereafter, it is cooled, hardened and the expander is removed to provide the thermo shrinkable tube 2'.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a reusable tube expander for expanding the diameter of plastic and rubber tubes or tubular profiles, particularly for expanding the tube to a predetermined diameter expansion ratio. The present invention relates to a diameter expander for tube material suitable for manufacturing heat-shrinkable tubes or tubular profiles having a predetermined heat shrinkage rate.

Here, "heat shrinkability" refers to the property of a pipe whose diameter has been expanded to contract due to the action of heat and almost recover its shape before diameter expansion.
It means "heat recoverability".

Conventionally, in order to impart heat shrinkability by expanding the diameter of plastic or rubber-based tubes or tubular profiles, the following steps were taken: (a) Applying pressure inside the heated tube or tubular profile, and (b) A method of expanding the diameter by taking out the tube heated in a pressurized container into the atmosphere and using a pressure difference; (c) A mechanical diameter expansion function of the internal IC of the heated tube or profiled material. A method of expanding the diameter by inserting a diameter expander having a diameter, or a method of expanding the diameter by forcibly inserting a heating tube into a mandrel of a prescribed shape, etc.

These conventional methods are known to have serious drawbacks as described below. In other words, (a) the diameter expansion method using internal pressure requires a sizing device to finish both the tube and the profiled material into specified dimensions and shapes, and the friction between the heat-shrinkable material in its expanded diameter state and the sizing device This method causes distortion in the axial direction due to the elongation of the material and the axial direction, which poses a problem in dimensional stability during heat shrinkage. If there is a thickness unevenness in the direction, the diameter expansion starts from a relatively small point, which has the disadvantage that the thickness unevenness is further emphasized. (B) In the diameter expansion method using pressure difference, there are problems of thinning and uneven thickness in the axial direction due to the sizing device, as in (G). There is a limit to the number of layers that can be manufactured, and it is not suitable for expanding the diameter of small-sized tubes and irregularly shaped materials. In the mandrel diameter expansion method, it is difficult to insert the heat-softened tube into the mandrel (even if the tube is very expensive), and it is difficult to insert the heated tube into the mandrel manually or mechanically. There are problems with the appearance, etc. Also, in the case of irregularly shaped materials, it is necessary to divide the mandrel, which causes many problems with the uniform distribution of strain, appearance, workability, etc., and it is difficult to pull out the I-drel after diameter expansion. It is.

The purpose of the present invention is to solve the problems of these conventional methods, and to produce heat-shrinkable tubes or profiled materials from small to large sizes having a predetermined diameter expansion ratio, in other words, a predetermined heat shrinkage rate, using the same principle. An object of the present invention is to provide a diameter expander for pipe material that can be manufactured extremely easily.

The present invention relates to a diameter expander for expanding the diameter of a plastic or rubber tube or a tubular profile, which is folded in the axial direction to form at least eight fins of the same length. It is an expandable hollow body, and the fin portions are located at equal angular intervals and extend parallel to the longitudinal axis of the hollow body, and expand to a predetermined thickness when internal pressure is applied. This is a diameter expander for pipe material, characterized in that it can be made into a hollow body.

The invention will now be explained by way of example with reference to the drawings.

The diameter expander 10 of the present invention is expandable in an axially folded shape so that at least three, preferably three to eight, equal length fins 1 are formed, as shown in FIG. It is a hollow body. The fin parts l are spaced at equal angular intervals f
As shown in FIG. 2, 1 extending parallel to the longitudinal axis of the hollow body IO, FIGS. FIGS. 2a and 2b are enlarged sectional views of three different examples of the diameter expander of the present invention, which is a hollow body provided, and FIGS. 2a and 2b are respectively
Figure k) is a perspective view of the main parts of the diameter expander in Figure and MLB Figure. In the diameter expander of the present invention, the hollow body can be expanded by applying internal pressure, and for this purpose, for example, one end of the hollow body in the pitching direction is sealed and a compressed air inlet is provided at the other end.

The material constituting the diameter expander of the present invention has the ability to sufficiently withstand the heat and pressure necessary to maintain a predetermined expanded diameter and shape when the diameter expander is used to expand the diameter of a pipe material, and to maintain the overall diameter. A tube that does not expand beyond a predetermined diameter and has sufficient strength to reduce the longitudinal extension and distortion of the expanded tube and obtain dimensional stability, and is folded. It is desirable that the fin portion 1 has strength to withstand repeated use, bendability, and flexibility for a certain period of time, and restores to its original shape after depressurization. Examples of such materials include sheets of plastic materials, such as sheets of heat-resistant plastic resins such as polyester resins, polyamide resins, fluorine resins, acrylic resins, polyimide resins, etc., or sheets of rubber materials, such as non-vulcanized sheets. or vulcanized natural rubber,
and 8BR, CR.

IR%I IR,BRSF! It is a sheet of synthetic rubber such as PR, silicone rubber, urethane rubber, etc. Chapter 8a
The figure shows one fin portion 1 of an expander according to the invention made from a sheet of such plastic material, for example polyester resin.
FIG. 0 is an enlarged sectional view of the 0 part.

The diameter expansion magnification achieved by the diameter expander of the present invention is as follows. When using the expander shown in FIG. 1b, the radial length b of the eight fins l is defined by K.
Up to a tube with an inner diameter slightly larger than 2b (8X 2
b/* ) / 2h # The diameter can be expanded up to 31.5 times. In addition, when using the diameter expander shown in Figure 1c, by specifying the radial length h of 1.2 fin portions 1, the tube with an inner diameter slightly larger than 2b can be made up to (12X 2h /*)/2 hζ; Can be enlarged up to 3.8 times. In this way, in the diameter expander of the present invention, the diameter expansion magnification can be increased or decreased by increasing or decreasing the number of fins, and therefore, by using multiple diameter expanders with different numbers of fins, the inner diameter before diameter expansion can be increased. It is possible to obtain expanded diameter tubes with different diameter expansion magnifications from the same tube, and even if the inner diameter is the same after diameter expansion, by using divine diameter expanders with different diameter expansion magnifications, the heat sink can be improved. “1;
It has the advantage of being able to obtain various heat absorbing tubes with a ratio of j', and the aggregate can be expanded to an extremely large diameter.

Each step of the process of expanding the diameter of a tube using the diameter expander IO of the present invention will be described with reference to FIG. As the diameter expander, a hollow body provided with eight fins tibN as shown in FIG. 1b is used. First, as shown in Figure 4, one end of the sealed expander 10 is inserted into the original tube 2 which has been heated to a desired temperature. Next, compressed air is supplied from one end of the diameter expander in the operator's direction through a nozzle or the like to apply a required internal pressure to the diameter expander. Figure 4b shows the stage at which the fin portion of the expander expands slightly and becomes a star-shaped hollow body 10' in cross-section, and Figure 4C shows the stage at which the expansion progresses further and the cross-section becomes an octagonal hollow body 10''. Figure 4d shows the stage at which the tube has expanded completely to become a hollow body with a circular cross section of 10#.After expanding the diameter to the required □ stage, the tube is cooled and solidified, the □ internal pressure is reduced, and then the expanded tube is expanded. Remove it from the diaphragm.

It is desirable that such a diameter expander does not expand beyond a specified diameter and that there is no elongation or distortion in the longitudinal axis direction, and for this purpose, the sheet of the above-mentioned plastic or rubber material used to construct the diameter expander should include: It is preferable that at least one layer of reinforcing cloth be closely attached to one or both surfaces, or provided at an intermediate position between both surfaces. Figures 3b and 8C are examples in which a supplementary layer 8 is adhered to the outer or inner surface of the sheet constituting the fin portion l in Figure iaa, and Figure 8d is an example in which a complementary layer 8 is adhered to both sides of the sheet. This is an example in which one reinforcing cloth layer 8 is placed in close contact with each other, and FIGS. 8e and 8f are examples in which one and two reinforcing cloth layers 8 are provided in the middle of both sides of the sheet, respectively. . The weaving direction of such reinforcing cloth layer' is preferably arranged parallel to the radial and longitudinal axes of the expander. By using a diameter expander made of a material reinforced with such a reinforcing cross layer, it is possible to obtain a heat-shrinkable tube with the same radial expansion as K and no elongation or distortion in the longitudinal axis direction.

It consists of a material reinforced with such a reinforcing cross layer.

Another advantage of the diameter expander is that even if there is some uneven thickness, the tip of the fin will first contact the raw tube when internal pressure is applied, and since the internal pressure is applied evenly, the contact area will be The position does not change, and the other parts begin to expand in diameter to have a star-shaped cross section as shown in Figure 4b, and then the valleys of this star-shaped cross-section come into contact with the original tube, causing the diameter to expand. progresses and finally the diameter expansion is completed, so the influence of uneven thickness is sufficiently alleviated, the expander itself does not stretch in the longitudinal axis direction, and the gap between the original tube and the expander caused by internal pressure is It is possible to obtain a heat-shrinkable tube that is free from distortion due to friction and has excellent dimensional stability.

By using a large number of diameter expanders of the present invention, for example, by using three diameter expanders 10 of the same size, the fifth
A straight raw tube 2 having a cross-sectional shape as shown in Fig. 5b is
It is possible to expand the diameter of the tube 2' having a cross-sectional shape as shown in the figure, and by combining expanders of various diameters, it is possible to expand the diameter of the tube to any shape and diameter. Furthermore, it is also possible to impart heat shrinkability to a tubular profile, for example a three-pronged branch pipe as shown in Figure 6a; in this case, eight identical tubes, as shown in cross section in Figure 6b, are One by one, the diameter expanders io are inserted through each of the eight branched tubes A to the unbranched tubular portion B, and the diameter is expanded to the state shown in FIG. 6c, resulting in the heat-shrinkable tube shown in FIG. 6d. It is possible to obtain shaped profiles, and in this way it is also possible to impart heat-shrinkable properties to the profiles.

When expanding the diameter of a tube using the expander of the present invention, regardless of whether the tube is a straight tube or a tubular irregular shape, the expander should be used to reduce the internal pressure after being cooled and solidified after expansion. It has extremely good workability, such as being able to be easily pulled out, has infinite possibilities, and has great industrial value.

The invention will now be explained by way of example with reference to the drawings.

Example l It has 12 fin parts l as shown in Fig. 1c, the radial length b of the fin parts l is 5 mm, and NE a a
As shown in the figure, using the diameter expander of the present invention made from a polyester resin sheet and having a wall thickness of o and '77F1m without using a reinforcing cloth, an inner diameter of 1 mm, a wall thickness of 2 mm,
, a cross-linked polyethylene tube with a length of 8 (l Omm) was expanded in diameter. First, this raw tube was heated to about 15oC with a heating device, and immediately after taking it out, a diameter expander with one end sealed in advance was inserted into the tube. Then, compressed air is supplied from the other longitudinal end of the diameter expander through a nozzle installed in advance for about 1 hour.
, 0 keg" of air pressure. Immediately after the diameter expansion, the tube was water-cooled and solidified, the internal pressure was reduced, and the expanded tube was extracted from the expander and its dimensions were measured. Thus, the polygon was similar to the polygon shown in Figure 4c. It has a dodecagonal cross-sectional shape, an inner circumference length of 116 mm (inner diameter equivalent to 871 mm), and a wall thickness of 0.7 mm.
mm.

A heat-shrinkable tube with a length of 297 nm was obtained.

- Cold weather 1 special - It has eight fin parts 1 as shown in Figure 1b, and the radial length h of the fin parts is i o im, which coincides with the radial direction and axial direction of the diameter expander. The inner and outer sides of one layer of glass cloth 8 having a weaving direction are coated with silicone rubber and cured by vulcanization.The total wall thickness is o, 5rI as shown in Fig. 80.
Using a diameter expander of L=, inner diameter 22 mrrLφ, wall thickness 2
As a result of measuring the dimensions of a FiPR-PE mixed cross-linked tube with a length of 1.000 inches, expanded in the same manner as in Example 1, and cooled and solidified, it was found that it was approximately circular as shown in Figure 4d. So, the inner diameter is 48 mm, and the wall thickness is 1.
．． A heat-shrinkable tube 2/ having a diameter of 1 mm and a length of 998 mm was obtained.

Example 8 Eight diameter expanders having eight fins 1 similar to those in Example 2 were prepared with an inner diameter of 4.5 mm, a wall thickness of 2 mm, and an i size of 5 (10
fim's EPR-PE admixture heated to 140° C., one end of the tube was sealed as shown in Figure 5a, and then each expander was injected with a simultaneous K i, 5 kl.
The diameter was expanded as shown in Figure 5b by enclosing an air pressure of 1.5 m, and then solidified by water cooling, and its dimensions were measured.Thus, the inner circumference length was 305 mm (inner diameter conversion n approximately 97 m, mm), and the wall thickness was 305 mm. A heat-shrinkable tube 2/ having a diameter of 1.1 mm and an average length of 494 mtn was obtained.

Example 4 Eight branched pipes A as shown in Figure 6a; inner q, shrimp 2
2 ntmφ, axial length 100mm, wall thickness 3m1
n and unbranched tubular part B: inner diameter 47 m, mm, lll]
14 cross-linked three-pronged branch pipes made of BPR-PE mixture and having a length in the #j direction of 150 fim and a wall thickness of a mm.
Immediately insert the same expanders 1o as in Example 2 through each of the tubes A to the tubular part B as shown in Figure 6b, and pierce these expanders with air at 1.5 kpm''. The diameter was expanded, and the dimensions were measured after water cooling and assimilation.

Thus, the diameter C shown in Figure 6d: inner diameter 4.8 mm-
, length 98mm, wall thickness 1.9m, and D: inner circumference length 805
mm (inner diameter equivalent: 97 mm), length 147 mm
A heat-shrinkable three-pronged branch pipe with a diameter expanded to a wall thickness of 1.8@tyt was obtained.

Example 6 Using a diameter expander having eight fins similar to that in Example 2, a crosslinked PE tube having an inner diameter of 22.7 Flφ was expanded. The length of this original tube and the wall thickness measured at eight equally spaced locations (first to eighth parts) clockwise on the circumference are the first
It was as shown in the table. Heat this tube to 140°C, immediately insert the diameter expansion tube, and reduce the internal pressure to 1 and 0 klV'.
c*", the diameter was solidified by water cooling, and its dimensions were measured. As a result, the inner diameter was 48 m with the wall thickness shown in Table 1.
An m-octagonal tube was obtained. The wall thickness of each part was reduced at approximately the same rate as that of the original tube, and the length of the tube after diameter expansion was 49,211 m, with little strain occurring.

Comparative Example 1 The same original tube as used in Example 5 was expanded in diameter by the following dividing method. A raw unit with a length of about 1 m was fixed to both ends of an iron pipe with an inner diameter of 40 mm in an airtight manner so that compressed air could be filled in. Then, the iron pipe and raw tube were heated in a thermostatic oven for 14 hours. (Heat evenly until 1'C,
Immediately, the diameter was expanded using an air pressure of 1,000 m, and the tube was solidified by water cooling before being taken out. The axially intermediate portion of this expanded tube was cut by 500 mm, and its wall thickness was measured according to Example 5.
Similarly, measurements were taken at eight equally spaced locations clockwise on the circumference.

Only the area near the thinnest first part is expanded to have a thickness of +9. is 0
．． However, the thickness of the fifth portion, which is the thickest, was 2.1 to 2.2 am. 1 more time this tube at 150℃
As a result of measuring the length after heating for 0 minutes to completely shrink, the result was 4+4 Q mWL near the thin first part, thickness (7
It was found that the strain in the axial direction was quite large, making the dimensions unstable, with a diameter of 465 mm near the second part.

As described above, the diameter is expanded using the diameter expander □ of the present invention, which is an inflatable hollow body that is folded in the axial direction so that at least eight fins of the same length are formed. do. In some cases, using conventional internal pressure or differential pressure expansion methods,
, compared to the case of expanding the diameter [5 shafts of expanded diameter:
It has the advantage that the strain in the 1fR direction is small, the dimensional stability during heat shrinkage is excellent, and even if the original tube has some uneven thickness, it is alleviated during diameter expansion.

The diameter expander of this invention has the following characteristics when compared with the mechanical diameter method:
il, the diameter of the diameter can be reduced, and the t of the fin part can be reduced.
By adjusting r.q a't, it is possible to easily reduce the diameter of .9 to 14 with a high diameter expansion ratio, and compared to the mandrel method, it is possible to achieve a uniform distribution of 11. The non-uniformity of the appearance when mechanically or manually pressed in (1, c (, also, the complexity of dismantling and pulling out the mandrel after diameter expansion, and the difficulty of expansion).
By reducing the internal pressure of the F element, it can be easily taken out, and it is also easy to design and manufacture products for VL diameters, making it extremely versatile.

[Brief explanation of the drawing]

1a, 1b and 1c are enlarged sectional views of different examples of the diameter expander of the present invention, and FIGS. 2a and 2b are perspective views of the main parts of the diameter expander of FIGS. 1a and 1b, respectively. 8a, 3b, 8c, 8d, 8e and 8f are partially enlarged sectional views of different examples of the diameter expander of the present invention, FIGS. 4a, 4b, and 8f, respectively. Figures 4c and 4d are explanatory diagrams showing each stage of the process of expanding the diameter of a tube material using the diameter expander 01 of the present invention, and Figures 5a and 5b are respectively illustrations of the diameter expander 01 of the present invention. Figures 6a and 6d are cross-sectional views showing the state before and after diameter expansion when three tubes are combined to expand the diameter of the tube, and Figures 6a and 6d are three-pronged branches made by combining eight examples of the diameter expander 01 of the present invention. The perspective views of the tube before and after the diameter expansion of the tube, Figures 6b and 6C are respectively the same as those of Figures 6a and 6d with an example of the diameter expander of the present invention inserted. FIG. 3 is a cross-sectional view of the tube. l... °fin part, 2... raw tube, 2/... enlarged diameter tube (heat shrinkable tube), 3... reinforcing cloth (glass cloth), 10, 10', Ill',
10'... Expander (hollow body), A... Branched 71
^, B... Unbranched tubular part, C... A, D after diameter expansion
...B, I) after diameter expansion...Radial length of the fin part. Patent Applicant: Furukawa Electric Co., Ltd. Procedural Amendment September 9, 1981 1, Case Description 1982 Patent Application No. 122138 2, Title of Invention: Diameter Expander for Pipe Materials 3, Person Making the Amendment Related patent applicant (5211) Furukawa Electric Co., Ltd. b. 6, Subject of amendment Detailed description of the invention in the specification, Drawing 7, Contents of the IIE (as attached) l, Specification, page 14, No. The 20th line “Figure 6d” is changed to “6C
Figures and Figures ad. 2. In the drawings, Figures 6b, 6C, and 6d are corrected as shown in Attachment ``1. Patent Application No. 51 No. 1221.38 2, Name of the invention: Conduit expander 3, Relationship to the case of the person making the amendment Patent applicant (529) Furukawa Electric Co., Ltd. (1) Specification, page 8, No. 20 Correct ``one end'' of the line to ``the other end.'' (2) In the same page, page 18, line 20, and page 15, line 6, ``1'' was corrected to ``and polyester cloth was used.'' (3) In the drawings, Figure 1b and IC diagram are corrected as shown in the correction diagram. Representative Patent Attorney Akira Sugimura Hidegai (1 person)

Claims (1)

[Scope of Claims] t. A diameter expander for tube materials for expanding the diameter of plastic and rubber tubes or tubular profiled materials, the diameter of which is expanded in the axial direction so that at least eight fins of the same length are formed. an expandable hollow body in a folded shape, the fin portions being located at equal angular intervals and extending parallel to the longitudinal axis of the hollow body; and expanding by applying internal pressure. And then! ? 0 and % that can be made into a hollow body of thickness and size! Diameter expander for pipe material. 1. The diameter expander according to claim 1, wherein the expandable hollow body has 3 to 8 fin portions. & The diameter expander according to claim 1 or 2, wherein the material constituting the expandable hollow body is a sheet of a silastic or rubber material. Table: The material constituting the expandable hollow body is a reinforcing sheet with at least one or more reinforcing cross layers provided on one side of a sheet of plastic or rubber material, or on both sides or at an intermediate position between both sides. □ The diameter expander according to claim 1 or 9. The diameter expander according to claim 1, wherein the reinforcing cloth layer is a cloth layer of fibers selected from the group consisting of natural fibers, inorganic fibers, and synthetic fibers.゛ □ a□ The reinforcing cloth layer is arranged in a direction parallel to the radial and longitudinal axes of the expandable hollow body. Expander.