JPH05501993A - tube with integral socket - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] tube with integral socket [Technical field] This invention relates to tubes made of plastic material with molecular orientation, especially integrally molded tubes. The present invention relates to the production of oriented plastic tubes with sockets.

[Background technology] It is conventional that molecularly oriented plastics can be provided with increased mechanical properties. It has been well known ever since. Orientation is determined by drawing or tensile under appropriate temperature conditions. Therefore, it is achieved. A large number of methods have been proposed, and therefore, in particular circumferential drawing This principle has been applied to plastic pipes to increase their bursting strength under internal pressure due to It will be done.

British Patent No. 1.382.580 discloses that by expanding a tubular stock in a cylindrical mold, Describes the production of circumferentially oriented polyvinyl chloride (vinyl chloride) pipe are doing.

Such methods present difficulties in constructing sockets for joining the tubes together. It will be done. There are also a number of satisfactory joints and individual coupling devices for this purpose. The preferred method is to have an integral enlarged bell-shaped section at one end of the tube and a section at the other end. Inserting the spigot and applying a suitable seal such as adhesive or rubber gasket I can do it.

The socket part of this straight tube is enlarged in diameter and is forced into the main body part due to fluid pressure. must be strengthened to handle the various other loads that the socket part is subjected to. It is generally considered necessary to do so. A common method is to scale the walls of the tube in proportion to its diameter. Thicken the walls of the socket.

British Patent No. 1.432.539 discloses a method that provides orientation in the circumferential direction. describes the manufacture of a socket part of enlarged diameter by expansion of the raw material in a female mold. ing.

This method is not sufficient due to the reduced wall thickness of the socket section and the following patent Another method is described in the specification. Australian Patent Application No. 29086’/77 In the specification, the socket part is constructed with a thickened wall part. Also, in Australian Patent No. 29088/77, the wall thickness is thin. A sleeve is placed over the socket portion opposite the socket.

These traditional proposals are cumbersome, do not lead to effective manufacturing, and thicken the raw material. This makes dimensional control difficult and ensures correct positioning of thickened sections. requires precise control of cutting of extrudates. Sleeve fitting is a secondary process Requires sleeve manufacturing and installation.

A vent or T-shaped pipe joint with a joint that is fixed to the pipe to support axial thrust. Another problem with oriented tubes arises if it is necessary to provide attachments such as Lift up. Such measures are useful when the axial strength of the pipe can be matched to the service load. Can be used for non-oriented plastic pipes. In oriented tubes, the axially oriented guide This advantageously increases the axial strength.

In the method described in U.S. Pat. No. 4,499,045, expansion is controlled. British Patent No. 1.382 by the use of a sleeve that moves sequentially along the material being controlled ．． The method described in '580 has been modified. Friction between this sleeve and the raw material results in longitudinal pull-out of the tube due to the biaxial orientation of the tube. Described in this The disadvantage of this method is that it is not possible to actively control the degree of axial withdrawal of the material. and a solution to the problem of manufacturing sufficient sockets in an economical manner has been found. do not come.

The purpose of this invention is to eliminate the need for thickening the material in the socket part Oriented Plus with integral socket at one end for increased strength and wall thickness An object of the present invention is to provide a method for manufacturing a tick tube. This invention provides the required relative thickness. Different axial draw ratios are applied to the socket and tube body to provide different characteristics. It is characterized by the use of controlled axial withdrawal of the raw material in such a manner that the

[Disclosure of invention] This invention provides an integral socket with an axial withdrawal wall that is less than the body of the tube. A circumferentially or biaxially oriented plastic tube consisting of a body with a cut at one end. This is what we provide. In addition, this invention also provides for the production of plastic pipes, which consists of the following steps. This provides a method for manufacturing.

(a) heating the raw material tube to the required orientation temperature; (b) aligning a portion of the raw material tube with the first axis; Forming a socket by pulling in the circumferential direction at a directional pulling degree, (c) The main tube is removed by pulling the raw material tube circumferentially at a second axial pull degree. forming a body, consisting in that the first axial withdrawal is greater than the second axial withdrawal. It is characterized by its small size.

In machines used for this purpose, the term "axial pull" refers to the circumferential pull of the free end. It refers to the elongation in the length direction achieved by punching. free end circumferential In drawing, the ends of the material are not axially tensioned and the rate of diameter increase is due to a tube with length and wall thickness reduced by a factor approximately equal to the square root Material is drawn from the length and wall thickness. In comparison, the circumferential direction of the fixed end In drawing, the length is constant and the wall thickness is increased by a factor equal to the increase in diameter. will be reduced. Therefore, fixed end withdrawal is compared to free end withdrawal. Due to the relatively thin walls and positive axial pull-out, the pull-out is caused by the axial molecular orientation of the plastic tube when carried out at a suitable orientation temperature. 6 [Brief explanation of the drawing] The first section has an integrally molded socket manufactured according to the method of the invention. A schematic cross-sectional diagram of an oriented plastic tube. Figure 2 is a similar cross-sectional schematic diagram showing the molding process of socketft. Figure 3 is a similar cross-sectional schematic diagram showing the cooling process of the socket after expansion of the socket; Figure 4 is a similar cross-sectional schematic diagram showing the expansion process of the main body of the raw material tube. FIG. 5 is a similar cross-sectional schematic diagram showing one modification of the manufacturing process. FIG. 6 is a similar cross-sectional schematic diagram showing yet another modification of the manufacturing process.

[Best mode for carrying out the invention] In one form of the invention, the socket is zero axially retractable and In another configuration, the cut body can provide positive, positive axial withdrawal. The bracket provides a reliable, positive axial direction, and the tube body provides a large reliable pull-out ratio. have. In yet another form, the socket has negative axial pull or pressure. The tube can be compressed and the main body of the tube can be pulled out.

Preferably, the socket wall has a circumferential orientation and the body has a biaxial orientation. It is possible to achieve differential axial pull-out combined with zero circumferential pull-out. The method of construction is shown in FIG. Mold 1 is approximately the final outside diameter required for the finished tube. have equal inner diameters. The end of the mold, i.e. the socket part 2, is attached to the socket of the tube. Fill the socket of the tube so that it is formed approximately to the required profile and contains a resilient seal. A groove (not shown) for forming the groove is provided as appropriate. The socket part is the completed pipe. constructed in such a way that it can be opened laterally or axially to allow removal of the It is.

The raw material pipe 3, which can be partially or totally preheated to the required orientation temperature, is connected to the sleeve 4. It is supported and covered by other supporting devices and guided into the mold 1. End of sleeve 4 A conical flange 5 fixed to the sleeve 4 in the mold 1 allows it to slide inside the mold 1. It is fitted. The sleeve 4 is attached to the rear part of the socket part 2 of the mold 1 as shown in FIG. is first moved to position flange 5 adjacent to 6. The end of the raw material pipe 3 is , the raw material tube is inserted into the sleeve 4 such that it engages within the end i10 that fits around the outside diameter of the raw material tube. It is fastened in the chuck 8 attached to the rod 9 so that it can be moved inside. ing.

Fluid at the appropriate temperature provides the consistent and uniform flow necessary for well-controlled withdrawal of material. Inside the feed pipe 3 via holes 11.12.13.14.15 to maintain the feedstock at temperature. circulated outside. The pressure exerted on the fluid through the hole 11 is as shown in FIG. Pressure is increased as required to effect material withdrawal or elongation, and the holes 13.14 ．． 16. Heating fluid is expelled from 17. During this process, the material is As it is pulled from the lid lO and the sleeve 4, the material of the tube socket is not pulled axially. I can't get nervous. Optionally, the end 7 of the raw material tube 3 is gripped by a chuck and the socket part 2 through the chuck 8 and rod 9 to achieve the desired degree of axial withdrawal. This allows tension to be applied to the raw material pipe 3. Optionally, compression again acts on the raw material pipe 3 This allows the negative pull-out and socket portion to be made even thicker.

Self-sealing or fluid-actuated resilient seals are provided in the sleeve 4 and end cap 10 to It can be used to help the expansion of the jacket.

Upon completion of the socket expansion, the cooling fluid flows into the cooling chamber around the socket part 2 of the mold 1. The jacket 18 is fed through the hole 17 to fix or solidify the oriented material of the tube socket. Made to harden. Pressure within the material is reduced to allow relaxation of the material body within the sleeve. The force is then reduced. Sleeve 4 can be partially pulled out during this process. Also, as shown in the third section, it can be completely pulled out. Next, pressure or hole 11? As a result, the main body of the raw material tube is expanded as shown in FIG. This kind of expansion #I naturally starts from the already expanded socket part 2 and moves towards the other end. Ku. The tensile force exerted on the raw material tube 2 by the chuck 8 via the rod 9 is generated in the circumferential direction. This prevents the length of the material tube from shrinking during axial expansion, creating thin walls and reliable axial tension. Jiru.

Upon completion of expansion of the tube, cold fluid flows through the holes 1], 112 to fix the orientation. The chuck is then released and the mold 1 is opened at the end M10 and the socket part 2. You can then remove the tube. Both ends of the tube are trimmed accordingly to form the finished product. will be processed.

In one variation of the process shown in FIG. A tensile force is further applied to the raw material tube by the chuck 8 so that a tension is applied. this Additional withdrawal can be effected before or during circumferential expansion.

In yet another variation of the process shown in FIG. 6, the process described in earlier U.S. Pat. Axial withdrawal is performed and controlled in the same manner as described in No. 045. By maintaining pressure within the material pipe during withdrawal of the sleeve, the material pipe 3 The friction between the sleeve 4 and a support device such as the sleeve 4 provided with the seal 19 can be used.

With this method, the rod 9 and chuck 8 can also be omitted, and the socket can be expanded. Utilizing the movement of the sleeve 4 and flange 5 in the axial direction within the mold before tensioning or during expansion It is possible to obtain the required axial withdrawal of the socket.

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Claims (22)

[Claims] 1. The body of a tube of axial withdrawal, consisting of a body with an integral socket at one end Circumferentially or biaxially oriented, where the socket has walls thinner than tic tube. 2. The walls of the socket have a greater degree of circumferential molecular orientation than the body of the tube. The plastic tube according to claim 1. 3. The walls of the socket are at virtually zero axial pull and the body of the tube is at positive axial pull. The plastic tube according to claim 1, which is blank. 4. The wall of the socket has a circumferential orientation and the body of the tube has a biaxial orientation. 2. The plastic tube according to claim 1, wherein the plastic tube is 5. The wall of the socket has a positive axial pull and the body of the tube has a large axial pull. A plastic tube according to claim 1. 6. The wall of the socket is in negative axial draw and the body of the tube is in substantially zero or positive axial draw. A plastic tube according to claim 1, which is directionally drawn. 7. A plastic tube according to claim 1, wherein the body of the tube is of positive axial draw. 8. (a) heating the raw material tube to the required orientation temperature; (b) heating a portion of the raw material tube to the first A socket is formed by pulling out circumferentially with an axial pullout degree of ( c) The tube of raw material is withdrawn circumferentially at a second degree of axial withdrawal. consisting of forming the body of The first axial withdrawal is smaller than the second axial withdrawal. How to make plastic tubes. 9. 9. The method of claim 8, wherein the feed tube has a substantially constant wall thickness over its entire length. Law. 10. 9. The method of claim 8, wherein the socket is formed before molding the body. 11. The socket is required to fix the molecular orientation of the socket before the formation of the body. The manufacturing method according to claim 10, wherein the manufacturing method is cooled to a temperature below the orientation temperature of . 12. Circumferential drawing of the raw material tube proceeds along the entire length of the tube to form the body of the tube. The manufacturing method according to claim 10, wherein the manufacturing method is carried out. 13. The circumferential withdrawal is directed towards the end of the tube opposite the socket. The manufacturing method according to claim 12. 14. The part of the raw material pipe that forms the main body of the pipe is supported in the sleeve before circumferential drawing. The manufacturing method according to claim 13. 15. 15. The product of claim 14, wherein the sleeve is extracted before the circumferential extraction step. Construction method. 16. Friction between the sleeve and the material tube occurs during at least part of the axial withdrawal. The manufacturing method according to claim 15. 17. Substantially zero axial pull is applied to the socket and positive axial pull 9. A manufacturing method according to claim 8, wherein the punching is performed on the body. 18. The socket is formed by circumferential pulling of the substantially free end The manufacturing method according to claim 17. 19. The body is formed by circumferential drawing of a substantially fixed end The manufacturing method according to claim 17. 20. Circumferential pull of body fixed end with incidental axial pull The manufacturing method according to claim 18, wherein the manufacturing method is formed by punching. 21. A concomitant axial withdrawal is performed by gripping the end of the material tube opposite the socket. 20. The method of claim 20 is performed by pulling during circumferential drawing to form the tube body. Manufacturing method described. 22. Circumferential withdrawal such that positive axial withdrawal creates a biaxially oriented body 18. The manufacturing method according to claim 17, wherein the method is applied to the tube at the same time.