JP2000512227A - Method for producing an end sleeve of a plastic tube and an apparatus for implementing the method - Google Patents

Abstract

(57) Abstract: In a method for producing an end sleeve 2 at a plastic tube 1 made of hot and moldable plastic, especially polyolefin or PVC, a substantially sleeve length at the end of the tube 1 is provided. Is heated to its deformation temperature or higher in a heating place, and in this state, is formed into the sleeve 2 by the sleeve forming tool 5 introduced from the pipe end 3, and the sleeve forming tool is formed. Before or after drawing 5, it is cooled below the deformation temperature. For the introduction of the sleeve forming tool 5, a tube 1 is provided at the outer end of the sleeve area 2 with a clamping device 13 which allows the introduction of the sleeve forming tool and engages the outside and inside of the tube volume. , 14, so that the sleeve area covers the sleeve forming tool 5 and cannot be fitted. An apparatus for performing the method is shown.

Description

DETAILED DESCRIPTION OF THE INVENTION             Manufacture of plastic sleeve end sleeves             Method and apparatus for implementing the method   The invention relates to plastics which can be molded hot, especially polyolefins or PVC. When manufacturing plastic sleeve end sleeves, the sleeve ends have approximately the sleeve length. Is heated to its deformation temperature or higher at the heating location, and The sleeve is formed by a sleeve forming tool introduced from above, and the sleeve forming tool is pulled. Production of plastic sleeve end sleeves to be cooled below the heat distortion temperature before or after drawing Construction method.   In addition, the present invention provides a taper that tapers conically at the sleeve forming location, for example, at the leading end. A sleeve forming tool configured as a sleeve forming mandrel moves relative to the longitudinal direction. While being heated at or above the deformation temperature at the heating location and having approximately a sleeve length The area of the end of the plastic tube with The invention relates to a device for carrying out the method, which can be introduced while being deformed.   Examples of materials for making such plastic tubes are high pressure and low pressure polyolefins. Polyethylene, polypropylene or other heat deformable plastics (thermoplastic Plastic) Especially PVC. Deformability is available for manufacturing materials and deformation Temperature, where the deformability depends not only on the main production material but also on the It is affected by the type, amount and consistency of the filler used. Generally speaking What is necessary is to expand the pipe necessary to make the sleeve, the wall thickness of the pipe, and the The shorter the length of the sleeve, the easier it is to manufacture the sleeve. Therefore, lumber Such sleeves, in large quantities up to the critical dimensions Can be manufactured so that, for example, certain tubes have diameters and lengths above this limit. When a sleeve is required, a small amount of filler and favorable heat deformation Comparable and expensive production materials must be used. At the end sleeve Special shapes are often separate injections, e.g. for thick or large diameter tubes. The end sleeve is manufactured during the molding process and connected to the tube or the existing tube is used during the injection molding process. Can be provided only in such a way that it is directly formed integrally with the end portion of the main body. This is The basic shape of the integrally formed part, for example, the sleeve, is significantly different from the basic shape of the pipe. The same is true when connecting square sleeves to round tubes. The idiomatic process here is The member to be connected is configured as a joint having a round pipe addition part, and the normal end thread of the pipe is used. Insert this fitting into the valve or re-install this part for mass production as described above. That is, it is configured as a member that is injection molded into a body.   Even for materials that are relatively easily deformable, the diameter and length of the sleeve compared to the tube diameter If is large, a significant problem arises. Until now, the end opposite the sleeve formation area Hold the tube in the section and push the sleeve forming tool into the heated tube end or reverse. Fixing a forming tool, for example a suitable mandrel, and fitting the tube onto this fixed mandrel; It was common to produce sleeves with the aid of Absorbs shear force in all cases Or as it occurs, the support of the tube takes place to the extent that the tube is not heated at all or only slightly . When the sleeve area is heated strongly to enable strong deformation, the sleeve forming process When introducing the tool, even if the tube is heated, the sleeve forming tool has not yet reached Waves may be formed in the former range. This is undesirable and actually produces waste. I will. The very gentle conical inclination of the sleeve forming mandrel at the leading end causes The introduction of Facilitate and facilitate, but undesired transition areas that are too long This occurs between a sleeve area having a partial diameter. Some remedies for this problem are long In the leave, the range of tube ends used to form the sleeve is often determined empirically. Heating to different strengths according to the value to be set, so that the outer end is significantly stronger than the inner end. Heating, and thereby the area of the sleeve that eventually engages the sleeve forming tool It was obtained by having a strength greater than the edge area before forming. I However, due to the large restraint capacity in the low temperature range, the deformation force to be applied again Increase. Almost all plastics used and tubes to be manufactured The drawback is that the so-called memory effect, that is, the thermal deformation of pre-manufactured parts, The molded part to be completely or partially returned to its original shape during heating or at normal temperature Is to try. Due to other conditions that must be maintained during sleeve production, The more the degree must be kept low compared to the melting temperature, the stronger the memory effect You. In the above example of a long sleeve, the memory effect is therefore directed to the inner end of the sleeve. So that the effect in the end area over time Stronger deformation occurs.   It is an object of the present invention to simplify the manufacture of sleeves to their dimensions, and Despite allowing the production of sleeves of larger diameter and length, The dimensional change of the tube made of material is largely or completely prevented by the so-called memory effect. To improve the first type of method. Some problems of the present invention are as follows. To provide a simple apparatus for implementing the improved method.   In terms of method, this task is to introduce a sleeve forming tool, A sleeve forming process is performed by engaging the pipe at the outer end of the sleeve area and the pipe wall at the outer and inner sides. The problem is solved by holding by means of a clamping device which allows the introduction of the tool.   The basic idea of the present invention is to very easily hold the flexible jacket at the introduction end later. If this is done, tensioning this jacket on the mandrel exerts pressure on the other end and It is significantly easier than putting it on this mandrel. Tubing is deformed Not only is it heated to a temperature that allows Of the crystals that produce the memory effect itself in the crystal structure To significantly higher temperatures where significantly larger portions liquefy than at temperatures permitted for Can be heated. The tube area is thereby very flexible and easily deformed Relatively large diameters and lengths of the same material The sleeve area can be manufactured and further deformations in the material affected by the memory effect can be reduced. Significantly prevented. This is because most of the crystal liquefies, and thus returns to its initial shape. Is lost. Tightening device allows introduction of sleeve forming tool Many configurations of this tightening device are possible, while maintaining the requirement that Noh. These structures, in principle, move radially from an initial diameter to a final diameter. With movable clamping pawls or variable diameter inner parts like expansion and pivot cores That these inner parts only slightly protrude from the inside of the tube in the holding area Or pushed into the inside of the pipe, so that the sleeve forming tool can be passed through , Can be designed.   According to a feature of the preferred apparatus for performing the method according to the invention, the sleeve area of the tube A retaining device is provided for the outer end of the tube so that the clamping device engages inside the tube wall. Holding part As the material stretches the tubing, it moves outward from the base position, which corresponds to the initial diameter of the tube end , Clamping position for passing the sleeve forming tool and pressing the outside of the tube end against the opposing holder Can be moved to   It is possible to use a separate drive for the spreading member. But the spreading part In particular, directing the movement of the material from the relative movement of the sleeve forming tool with respect to the pipe, Advantageous and simple. In this case, a suitable clamping device is later installed in the existing sleeve forming area. Is also possible. Thereby, structurally, the holding device has an outer sleeve. That is, a sleeve forming tool can be introduced into the pipe end through the outer sleeve, and The side sleeve has an annular seat on the tube side for abutting the outside of the tube end of the expanded tube on the facing holder. At the introduction side away from the annular seat and out of the tool guide path. Is held in the outer sleeve and the free end of the spreading arm in the inoperative position forms a small angle of incidence. Projecting inward into the longitudinal extent of the annular seat, where The sleeve forming tool that can be closed and forms the auxiliary means of introduction of this tool at the same time The spreading arm to be formed is spread while expanding the end of the tube, so that the spreading arm forms a sleeve. At the free end, the tube end is held opposite the annular seat from the inside of the tube while allowing the tool to pass A particularly simple solution is to press against the body and hold the tube during subsequent sleeve formation. can get. An annular ball of a sleeve whose opposing retainer is at most used to receive the sealing piece Preferably, it is provided so that it extends only to the edge. The ring bead itself is a public As is known, in some cases, the outer mold is used to expand the groove area using a splittable outer mold. Or by using a revolvable oscillating core of a sleep forming tool. Can be   According to a development of the invention, the spreading arm extends the angle of incidence to the outer sleeve. Consists of a leaf spring which is clamped and mounted with a uniform circumferential distribution. Wide The use of leaf springs as bar arms does not require joints and creates an advantageous process of spreading movement. Easily accepted for introduction of sleeve forming tools inside the sleeve or at shallow grooves This has the advantage that a thin leaf spring can be used.   One or more annular chambers are provided as opposed holding members for the annular seat, Similarly, it can be pushed into the heated tubing at the clamping position. Thereby The sleeve end is securely retained and has a clean appearance similar to the outer edge of the crown.   Specially shaped sleeves are also manufactured because of the basic equipment according to the invention. Therefore pickpocket The forming tool and the outer sleeve are at least bordered by a suitable arrangement of the spreading arms. Surrounding, different from the basic cross-sectional shape of the rotating body, for example, square or polygonal cross-sectional shape, I have it for the production of sleeves.   In the first example of producing a long sleeve from HD-PE, an inner diameter of 104 mm and 5 mm Thicker tubes require sleeves with a final inside diameter of 122mm and a length of 400mm Heating to different temperatures with appropriate difficulty, with the inner end of the sleeve area The part reaches a maximum of 120 ° C and the outer end reaches 140 ° C. In the method according to the invention, the same The tube is kept at 140 ° C or higher in the entire range, and preferably in the range of 200 ° C. Heated very close, then deformed.   Further details and advantages of the invention can be found in the following description of the drawings.   The invention is illustrated in the drawings by way of example.   FIG. 1 shows a tube with an end sleeve made according to the invention;   FIG. 2 shows a tube with a tube end introduced before the sleeve is formed. Figure 2 shows in cross section a holding device according to the invention at a leave forming location;   FIG. 3 shows, in an illustrated manner corresponding to FIG. Fig. 3 shows a sleeve forming mandrel of an incoming sleeve forming location.   According to FIG. 1, at the end of the tube 1 a very long and large diameter is compared to the tube diameter. The sleeve 2 is formed integrally, and the end 3 is held during formation of the sleeve. At a location remote from part 3 for receiving a sealing ring formed, for example, by bulging into an outer mold It has an annular bead 4. During manufacture, the sleeve areas 2, 3, and 4 of the pipe 1 Is heated to a relatively high temperature, so the memory effect in the finished sleeve Have been practically prevented even when made from materials sensitive to this effect.   For the sleeve forming site according to FIGS. 2 and 3, a known holding device or feed for the tube 1 is used. Device and a tube having a conical end portion 6 which can be extended in its longitudinal direction with respect to the tube. A leave forming mandrel 5 is provided which blows into the area where the bead 4 is to be formed later. Nozzles, and these blow nozzles provide a suitable sleeve range. After production of the bead, it is blown again into a disassemblable outer mold for release of the bead. Bead For manufacturing, the pivot core on the mandrel 5 can also be used.   Important for the invention is the holding device 7 according to FIGS. 2 and 3 in the exemplary embodiment. The holding device 7 includes an outer sleeve 8 which is connected to the outer end 9. A little larger than the mandrel 5 at the location and near the annular seat 10 at the inner end 11. It extends slightly from the inner end 11 itself to the recess 12. Withdrawal The annular portion 12 is an annular groove having a triangular cross section, and the outer side surface of the annular groove is toward the end 9. Once descended again to You. On the inclined side surface of the groove descending toward the end 11, the end 11 and the annular seat 10 Leaf spring or spring having an angle of incidence gradually falling toward and serving as a spreading arm A tongue piece 13 is attached. The free ends of the spring tongues 13 gather closely on a circle. For example, the spring tongue 13 has a width on the order of 10 mm and a thickness on the order of 1 mm.   According to FIG. 2, the tube 1 to be heated is introduced at its appropriate end into an outer sleeve 8. The edge protrudes very slightly from the annular seat 10, and the end of the spring tongue 13 is 3 is engaged. Now, the sleeve forming mandrel 5 enters from the right, so that the outer sleeve is formed. A plate which spreads the spring tongue 13 until it is almost in contact with the inner wall of the tube 8, with the plate engaging the tube end 3 A spring or leaf spring 13 spreads this tube end and presses it against the annular seat 10. Edges on annular seat 10 When one or a plurality of annular chambers 14 are present in parallel to From outside into the tube end 3, which now forms the sleeve end. The end of leaf spring 13 It is pushed outward into the sleeve end 3. From this position, the plate spring 13 swings outward. In any case, the extended sleeve end is retained by the outer sleeve 8 so that The entering sleeve forming mandrel not only provides the introduction aid through the leaf spring 13 but also 5 is reliably prevented from compressing the sleeve area of the tube when overlaid. As mentioned above After the sleeve forming process and the attachment of the annular bead 4 are completed, the sleeve 2 needs stability. Pre-cooling of the sleeve area can be carried out until The mandrel is pulled out or the tube 1 with the finished sleeve 2 is a sleeve forming mandrel Drawn from.

Claims (1)

[Claims] 1 Plastics that can be molded in hot state, especially from polyolefin or PVC When manufacturing the end sleeve of a chip tube, the area having the sleeve length at the end of the tube should be approximately Heated to its deformation temperature or above in the heating place, and introduced from the end of the pipe in this state The sleeve is formed into a sleeve with the sleeve forming tool, and before the sleeve forming tool is drawn out or Is a method for producing an end sleeve, which is later cooled to a temperature not higher than the heat deformation temperature. At the outer end of the sleeve area (2), the pipe (1) is introduced into the outside and the outside to introduce the forming tool (5). Clamping device (13, 14) engaging the tube wall on the inside to allow introduction of the sleeve forming tool A method for producing an end sleeve of a plastic tube, characterized in that the end sleeve is held by: 2. A sleeve that tapers conically at the point where the sleeve is formed, for example, at the leading end. A sleeve forming tool configured as a forming mandrel moves relative longitudinally, e.g. If it is heated to the deformation temperature or higher at the heating place and has a nearly sleeve length Spread this area into the area of the end of the chip tube so that it becomes a sleeve and deform it. The outer end (3) of the sleeve area (2) of the pipe (1) Is provided with a holding device (7), and the tightening devices (13, 14) disengage the spreading member (13) engaged with the pipe wall. The spreading material (13) is adjusted to the initial diameter of the pipe end (3) while stretching the tubing. Through the sleeve forming tool (5) and the outside of the pipe end (3) outward from the corresponding basic position. Claims: It is possible to move to a tightening position for pressing against the opposing holding body (14). Item 10. An apparatus for performing the method of Item 1. 3. The holding refit (7) has an outer sleeve (8), and the sleeve is passed through this outer sleeve. A forming tool (5) can be introduced into the pipe end (3), An outer sleeve (8) applies the outside of the tube end (3) of the expanded tube (1) to the opposing holder (14). Holding the annular seat (10) on the pipe side, separate from the annular seat (10), and The spreading arm (13) as a spreading member is held by the outer sleeve (8) and spreads in the non-operation position. The free end of the barb (13) forms a small angle of incidence and moves inward into the longitudinal range of the annular seat (10). A sleeve which protrudes and can fit into the tube end (3) which has not yet been deformed and enters The forming tool (5) has a spreading arm (13), which simultaneously forms The spreading arm (13) allows the arm (13) to pass through the sleeve forming tool (5). At the free end of the tube end (3) from the inside of the tube at the opposite end of the annular seat (10). ) And holding the tube (1) during subsequent sleeve formation. 3. The device according to 2. 4. The spreading arm (13) is clamped at an angle of incidence to the outer sleeve (8) and has a uniform circumference. 4. The method according to claim 3, wherein the spring comprises a leaf spring mounted in a circumferential distribution. The described device. 5. One or more annular chambers (4) are provided as opposed holding bodies for the annular seat (10), Like the end of the arm (13), it is pushed into the heated tubing at the clamping position The device according to claim 3 or 4, wherein 6 The sleeve forming tool and outer sleeve can be reduced Both in the edge range, different from the basic cross-sectional shape of the rotating body, for example, square or polygonal cross-sectional shape , For producing a suitable sleeve. An apparatus according to one of the preceding claims.