DE1162543B - Process for the production of plastic ducts - Google Patents

Description

Process for the production of plastic ducts The invention relates to a method for producing walls for plastic ducts with at least one continuous longitudinal seam, which is shipped flat when the longitudinal seam is open and then a liquid-tight one by closing the seam in place Form flexible duct, in which with the long sides of a plastic tape interlocking, cle plastic slide fastener tapes firmly connected will.

Such plastic cladding tubes and processes for their manufacture are known per se. The invention is based on an improved manufacturing process propose to separate pieces of a thin, pliable plastic material to be welded together under heat.

According to the invention it is provided that a pair of slide fastener tapes is heated, the heated side webs of these bands transversely to the longitudinal extent of the tape and then the side bars of the slide fastener tapes be welded to the edges of a thin plastic tape, the mutual Toothing certain parts of the slide fastener tapes are turned away from each other.

A preferred embodiment of a method according to the invention is characterized in that the thin plastic tape is initially cooled and thereby is held flat and then the plastic tape stiffened by cooling its pages; edges is welded to the Oleitverschlußband.

In a further preferred embodiment of the invention the slide fastener tapes during welding to the plastic tape under one the same straight tension is set.

The strips to be welded together can be used in sections can be advanced, and the pressure exerted on the weldment can be maintained for a long time until the heated material has solidified again.

The plastic tape is expediently cooled to a temperature whose Shore hardness is the same as the Shore hardness of the slide fastener tapes.

Slide fastener tapes, which are used to carry out the process can be used particularly advantageously according to the invention, are characterized in that that the slide fastener tapes have a wide, flat fastening strip on another side have, in which Einmtte are provided, which extend from its edge extend inward and through that of the fastening strips in single Lobes divided whose adjacent edges are in direct contact with one another.

The walls produced by the method according to the invention for plastic ducts can also be characterized in that the side web one of the slide fastener tapes on the thin plastic tape to form a while closed tube under the slide fastener straps in a larger flap Distance inwardly from the side edge of the same is attached.

The method proposed according to the invention is general Applicable to the manufacture of numerous articles and products which are classified as essential elements are thin sheets or sheets of pliable, pliable thermoplastic Have plastics, so that they are welded together after the previous welding techniques are difficult to manage and control.

The problems that arise in this regard are in particular the Known to those skilled in the art who are concerned with the manufacture of seamed doors Employing pipes made of plastics, as they are widely used for the encasing of pipe systems, Cables and wire rods with branches and for many other similar applications be used. For example, these tubes unhook a thin main body plastic synthetic resin material, which can be multilayered or single-layered and the longitudinally opposite side edges with plastic slide lock tapes is provided, which are welded to the main body. The bands have mating locking elements that work together so that they Form a longitudinal seam that can be quickly opened and closed again for various purposes can be. These ducts made of synthetic resin material, as they have been produced up to now, were not yet completely satisfactory as difficulties arose, one firm and uniform weld seam between the thin, flexible band elements and the equally thin, pliable, and easily warped strip of the main body to manufacture.

The main body strip tends to pull out of it for heat welding to emigrate to the desired location. The reasons for this difficulty in the appropriate Arrangements for welding are different. For example, they are usually used slide fastener tapes made of plastic by means of extrusion molding.

Accordingly, they are rarely available in a straight, flat shape. Rather, the slide fastener tapes contain waves, vortices and other irregular wedges, because of which they are difficult to handle and in the desired aligned position are to be held with the part to which they are to be welded. Also in those cases where facilities are provided to keep the tapes in place during welding to be held in alignment, the tapes show after the holding pressure is lifted Tendency to revert to their previous wavy, irregular state. However, this not only leads to a product that is different in its external appearance is not uniform and unsightly, but also leads to poor functioning the sealing seam and premature failure of the same during use. The warped and wavy design of the slide lock elements transmits on the adjacent base to which the slide lock are attached should, so that, for example, the cladding tube or another product no more than First quality product is negotiable. If the product to be manufactured is a plastic Cladding tube shows that the seam, which is, for example, gas- and liquid-tight should be, is defective and does not fulfill the intended purpose, as moisture, Liquids or gaseous media can penetrate.

Furthermore, it can happen that the pipe becomes loose during handling or opens prematurely and unexpectedly at another time.

Various attempts to overcome these and other difficulties, however, have not yet had complete success.

It was found that undulations, distortions and other irregularities, as they are characteristic of seams formed in plastic synthetic materials are, in many cases, on a locally non-uniform extension and extension of the material at the seam, as they are in the formation of the seam due to heat and light pressure. By heating the material along the Naik this softens with the result that the softened plastic material when applying the welding pressure in order to unite the two heated surfaces is diluted and drawn out. This stretching of the material occurs mainly in the longitudinal direction of the seam. That Material in close proximity on each side the seam, on the other hand, is only slightly heated and not stretched.

It follows that a seam is formed by melting of the plastic material inevitably leads to internal tension and tendency causes the material to bend and warp.

If the two components to be welded together are identical or are almost the same, is the disturbed state on the molten surface of the Seam restricted so that it is imperceptible if not examined carefully will. However, if the materials to be fused are substances with different Containing Shore hardness characteristics, a stronger differential extension occurs of the two components along the seam and the adjacent surface. Accordingly you get a very pronounced distortion of the material, the extent of which is largely depends on the difference in the Shore hardness of the components.

The problem described is with the application of slide fastener tapes on the opposite edge of strips of plastic plastic, e.g. B. at de.r production of plastic tubes with longitudinal seams, particularly acute. So that the slide lock holds together with sufficient force, should the interlocking slide fastener tapes of a Shore hardness in the range between 85 and 95, whereas those for forming the body of the cladding tube in general using plastic strips soft and pliable with a Shore hardness in The range should be from 60 to 80. This difference in the Shore hardness of the two Major components provide uneven elongation and, consequently, distortion of the main body strip welded to it relative to the much harder ones Slide fastener tapes. Even if accordingly relatively straight and flat Parts of the joining process according to the known welding techniques under the influence of heat are subjected to an economically unsatisfactory product is obtained, that is distorted by wavy and distorted edges.

The invention is therefore intended to produce products that are composed of plastic components are composed and in which the mentioned and further disadvantages can be avoided. If the parts to be joined together have the previously mentioned plastic slide fastener tapes and a longer thin-walled, ger Strips of plastic material are which form the main body of a flexible duct forms, will be much better and very satisfactory results through application achieved using the working methods described below.

The eaten and curled strips of slide fastener tape become before the union with the main plastic body of the pipe in such a Pretreated in such a way that the internal gaps within the ligaments are loosened. The slide fastener tape is then attached to the edge of its side web connected to it slotted to separate the tension surfaces from one another in the longitudinal direction of the belt to separate. The slide fastener tape is then held under slight tension when it is advanced through the sealing station where the with the main strip to welded point of the same pressed along the connecting line against this and to a corresponding welding temperature at the same time as the pretreatment the slide fastener tapes is brought. The main body to which the straps are welded are to be pretreated by subjecting it to a strong cooling, keeping it flat and straight, with the result that this main body becomes stiff and its desired shape for the connection for the short period of time maintains what is required to weld it to the slide fastener tapes. The degree of cooling is very important. Best results will be achieved when the softer and more pliable main body is cooled down to such an extent that that it becomes temporarily stiffer and adheres to a Stiore hardness that is currently the case the saw weld seam formation roughly agrees with that of the slide fastener tapes. For this purpose, the main body is cooled a little more than the optimal Shore hardness requires a temperature rise between the cooling chamber and the sealing station, which are normally arranged at a certain distance from each other to compensate. A convenient working method is to move the main body through the cooling chamber to let it run immediately before it has become stiffer from the cooling Welding station is advanced. It turns out that the main body is his Maintains the desired shape and that its handling and conveying is facilitated, its side edges being uniformly in the desired location with an accuracy that could not be achieved so far. In addition, there is a distortion completely avoided due to the uneven flow of the weld seams. In addition, it is found that the cooling of the main body is firmer and more uniform Welding supplies. Furthermore, there is less tendency that this is in the immediate vicinity Plastic material lying near the weld during the welding process is disadvantageously diluted.

The invention is further developed with the aid of the description and the drawings explained. The drawings show in FIG. 1 schematically shows a preferred mode of operation, around deformed side locking straps made of plastic materials in a straight line To bring form, Fig. 2 is a schematic representation of the main body as it is to Production of continuous casing tubes made of plastic plastics is used, and mechanical auxiliary equipment for pre-treatment and processing of the same, FIG. 3 is a perspective view of a Hü11 pipe while the pipe is being attached on a wire bundle, FIG. 4 shows an enlarged partial cross section of a slide fastener seam after closing the seam, from which in particular the position of the cover flap can be seen is.

From Figs. 1 and 2, the two main devices can be seen, as used for the production of tubes from plastic according to the Velrfahren can be used according to the invention. The essential in F i g. 1 device shown is generally designated by the reference numeral 10. The device 10 includes a longer furnace 11 with an opening 12 open on both sides, by soft at least one pair of slide fastener tapes 13 and 14 made of plastic plastic can go through. The furnace 11 is in its interior with some heating elements provided, which can be controlled in the usual way, around the plastic bands to heat up to the temperature at which the plastic material will flow begins. The respective working temperature in the furnace 11 can depend on the The conveyor belt speed may be higher or lower. The treated tape is held by guide rollers or a conveyor belt. That in the sense of the representations The band entering the furnace from the right and not yet treated should create a very irregular, have wave-shaped stirrers on its side bars, as is the case for the commercial available ribbons made of plastic material is characteristic. the Belts 13 and 14 are in the sense of the illustration when entering the furnace 11 with one another unite, since this has proven to be practical in the handling of the belts, although this is not absolutely necessary.

When the tapes leave the exit end of the opening 12, they are pretty hot and soft. Because of this, the ligaments stretch easily to the small extent that is desirable and necessary for the alignment of the tapes is. In this way, the tapes can assume a straight, flat state. This straightening is necessary for conveying the strip through the furnace light tension significantly supported.

To further ensure that the tapes do not move when cooling discard again and become wavy, the wide side webs 15 and 16 of the Ribbons cut, for which purpose they are guided by a pair of cutting rollers 19 and 20. This process step is of great importance. At least one role each the pairs of rollers is provided with oblique knives 21, which the side Incise risers 15 and 16 along cutting lines 22.

The cutting lines 22 are preferably at an angle to the marginal edges the tapes. The cutting lines 22 are intended to be contiguous areas of the tape with regard to the transmission of internal stresses in the tape strips from one another insulate without, however, the strength of the strips suffering too much target. The loss of strength is particularly negligible if all Place or Telliaschen the side strips on the plastic main body of a pipe are indicated, as will be described in the following. The roles 19 and 20 are connected to drive means (not shown). Roles 19 and 20 can continue to convey the strip to be treated through the furnace 11.

After the tape has been treated as described, it is cooled. The two halves of the Gleitverschlußb andes are separated from each other, so that Prepare welding on opposite sides of the band forming the raw body.

Although it is not shown in the drawings that the bands 13 and 14 are fed directly to the device for producing the pipe, it is understandable that optionally the tapes are attached at the same time as they are attached the pipe body can be treated, as well as the operation for removal the internal stresses are carried out separately from the welding of the bands will can. Either of these two working methods is possible. It should also be mentioned that the straightened and freed from their internal tension ligaments bent or Can be aligned in any way depending on how this applies to the connection with the tubular body is desirable.

The in F i g. 2 device includes a cooling chamber, which is designated generally by the reference numeral 23. The cooling chamber 23 has narrow slots 24 extending across their opposite sides which the main body band 32 of thin plastic material runs when it closes the welding station is promoted. The cooling chamber 23 can with rollers, one another be provided on the both surfaces of the belt 32 made of the plastic plastic material abut and keep it straight and flat while it cools and stiffens. To the Any cooling means may be used to cool the belt 32. The cooling is regulated in such a way that the main body becomes so much stiffer, as is necessary to the Shore hardness of the same temporarily in accordance with the Shore hardness of the side bars 15 and 16 of the slide fastener tapes 13 and 14 to bring, based on the point in time at which the ligaments between the welding electrodes 27 and 28 are located. Since the Shore hardness at normal room temperature the slide fastener tapes are conveniently in the range of 85 and 95 so the interlocking lobes and grooves of the same have a corresponding engagement force preferably only the band 32 but not the strips of the slide fastener pre-cooled. It is useful to cool the belt 32 a little more than after Shore hardness determination would be required in order to warm up as the strip passes through equalize up to the welding station.

In some cases, due to special characteristics of the various plastic plastic materials to be united with one another same elongation of the parts in the longitudinal direction of the seam a different one Pre-cooling both parts or heating one and cooling the other and'or temporarily not the same Shore hardness characteristics of the parts to be united require. Accordingly, it should be made clear that a flat and not distorted Interface between plastic plastic materials of different characteristics by changing the temperature of the parts immediately before the union the same can be achieved by Versehweißung.

The main body band 32 stiffened by the cooling is left run directly from the cooling chamber 23 in grooves 26, which in the edges of a A pair of parallel tape guide parts 25, 25 are provided, which are made of electrically. consist of non-conductive material. The grooves 26 have an appropriate cross-section, around the relatively strong flap and groove parts 17 and 18 of the slide fastener tapes take up, while the flat side webs 15 and 16 of the bands completely free stay and are directed towards each other in the same plane. The tape guide parts 25 are attached accordingly so that they can be used to adapt the device for the Manufacture of pipes of various diameters and, accordingly, of strips different dener width set in greater and smaller distance from each other can be.

The welding of the slide fastener strips to the pre-cooled and Correspondingly stiffer main body strap 32 is preferably made with the aid of performed by two pairs of heating and pressing electrodes 27 and 28. The top pair 27 of these electrodes is held by vertically reciprocating rods 29, so that these electrodes are relative to the stationary lower pair of electrodes 28 can be raised and lowered. The electrodes 27 and 28 are made of metal and have smooth, flat, opposing surfaces. You are means Wires 30, 30 connected to a high frequency generator. That way will ensured that the walls are mainly in the space between the electrodes while the electrodes themselves remain relatively cool.

The band 32, which has the desired width for the main body of the Has cladding tube is conveyed in the longitudinal direction of the electrodes 28, each its one edge 33 between the line up to which the cutting lines 22 inward go, and the locking tabs and locking grooves having part 17 of the Slide fastener tape with the side web 15 is. The other side edge 34 of the Tape 32 preferably extends over the outer side edge of the closure tab and part 18 of the sliding locking band having splines with the side web 16 out, so that a cover flap 35 is formed in the finished cladding tube. This tab lies flat in the deeper cut during welding Base part of the groove 26 of the associated guide part 25.

The welded parts are intermittent, for example by means of of the rubber-coated conveyor rollers 37 and 38, which are in opposite directions turn, advanced. The individual advancement steps are determined by the length of the electrodes 27 and 28 are limited and occur when the electrodes are separated from one another and de-energized are. After the advancement step, the electrodes are lowered to lock the slide tire to the underlying parts of the still cold and rigid main body 32 to press. The high frequency generator is then switched on, with the touching Set the plastic parts to be heated to their melting temperature, after which the Current flow is preferably automatically interrupted while the electrodes are still Keep pressing each other gently until the parts are firmly fused together are. The time required for the pressing process is about half that for the heating needed time. The welding processes described are preferably in more detail timing with the intermittent advancement of the main body ligament and the slide fastener tapes. This operation can either be from Be done manually or automatically, the latter being preferred as there is no such thing special attention of the operator or any other manipulation required are. For custom-made products or for reasons of economy however, the tapes can also be inserted under the electrodes by hand. One or more of the other operations can also be carried out by appropriate Manual operation can be carried out.

It turns out that smaller length compensations of the side webs 15 and 16 of the slide fastener tape, as they are for balancing internal tensions and a Corresponding elimination of distortions Twists or the like required sinl can be facilitated by the incisions 22. This corrective effect will continue improved when the sonic lines run at an acute angle to the belt surfaces. This inclination is not, however, for a slight overlap of the sole litz edges absolutely prerequisite, as in the context of the corrective effect during the Laying the tapes on top of one another and welding them together takes place.

The finished pipe body as it is from the conveyor rollers 37 and 38 expires can be rolled flat onto a shipping roll 40 for packaging.

The roles40 can be provided with side windows to free the lying edges of the tubular body during subsequent handling and during to protect shipping.

The finished cladding tube denoted by the reference numeral 42 is provided with a slide valve 43. From Figure 3 it can be seen how the cladding tube is arranged around a group of electrical wires 44, with only one small number of wires is shown. It is perfectly understandable that the cladding tube 42 produced in any diameter according to the bandwidth so that it can encompass a bundle of wires 44 of any size can. The slide 43 consists of a slide body 45 and a pull tab46, which slide along a retaining strip 47 in accordance with conventional technology can. It goes without saying that the slide is shaped so that it can be over the the parts 17 and 18 of the slide fastener tapes which have the closure flaps and closure ribs fits. Inside, it is shaped so that it can engage these parts in and out of their gearing depending on the direction in which the slide is pulled along the pipe will.

A particularly suitable one is shown in the enlarged illustration in FIG Form of training of the interlocking webs and grooves of slide fastener tapes evident. Each band has a pair of longitudinal grooves 48 which are shaped so that they can accommodate the correspondingly shaped webs 49 of the other band flush. The spenelle training of the slide fastener parts can of course also be in a different one Form, although such designs are preferred in which the Versohlußteile mutually cooperate in such a way that when they intervene a liquid and moisture-tight Degree is achieved.

Preferably, the tab 35 completely bridges the slide fastener tapes and still slightly overlaps the opposite side edge 33 of the plastic Material existing main body 32 of the cladding tube. Accordingly, this covers it Flap the connection point of the cladding tube wall down completely so that for the wires 44 provide a complete closure independent of the slide fastener tapes is formed. This not only makes it easier to close the straps quickly, but also prevents protruding wire fibers from moving outward into the web turn the slide valve 43 when closing the slide lock. The tab furthermore prevents dirt particles or other foreign parts into the grooves of the Slider lock occur during the locking process, a protrusion that leads to a poor functioning and lead to an unclean Versdhiuß of the cladding tube could.

Another important task of the cover flap 35 is to provide a To prevent injury to the wire line when the slide 43 is the Gleiwerscffluß locks. Furthermore, the closure is held together, if that with the wire ventilation filled duct is bent sharply, because in this case the wires then the Press the protective tab firmly against the inner walls of the pipe, where it is crusted by friction is held. Furthermore, the protective bag prevents the entry of a solvent, as it is sometimes used to seal the sealed seam. if If such a solvent gets inside the pipe, it could damage the synthetic resin insulation damage to the wires enclosed in the duct.

The Plastiictesle can be made of any plastic, as he is known in great numbers. Polyethylene and the various vinyls are particularly suitable. However, at this point they are only intended to be explanatory Examples are mentioned.

It should also be emphasized that the plastic cover described is not is only suitable for wire reinforcement, reinforcements or as a duct for electrical wires, probes can also be used for many other purposes. For example the duct can be used as a cover for pipelines of all types, with it serves to protect or improve the appearance of the same. Furthermore can it is used to hold other parts on the pipe, e.g. B. a thermal insulation layer on steam pipes.

The basic procedure as described, can be applied to products in the manufacture of which it is desired To form hot welds, with one or more of the components to be combined is held in a simple or a compound curved position. In in this case this part is then cooled while it is in the desired curvature is held. Similarly, the assembly of plastic sheets can be significant can be facilitated if the foils by the specified pre-cooling before production the weld seams can be made stiffer.

Claims (7)

Claims: 1. A method for producing walls for plastic cladding tubes with at least one continuous longitudinal seam, which is flat when the longitudinal seam is open can be shipped and then by closing the seam in place and Place a liquid-tight, flexible duct with the long sides a plastic tape interlocking plastic slide fastener tapes be firmly connected, characterized in that a pair of such slide fastener tapes is heated, the heated side webs of these bands transversely to the longitudinal extent of the tape and then the side bars of the slide fastener tapes be welded to the edges of a thin plastic tape, the mutual Gearing specific Parts of the slide fastener tapes from each other are turned away. 2. The method according to claim 1, characterized gekennzeichne.t that the thin Plastic tape is initially cooled and held flat and then the Plastic tape stiffened by cooling at its side edges with slide fastener tapes is welded. 3. The method according to claim 1, characterized in that the slide fastener tapes while welding to the plastic tape under a straight one holding the same Tensile stress can be set. 4. The method according to claim 1, characterized in that the together The tapes to be welded are advanced in sections and at the welding point applied pressure is held until the heated material solidifies again Has. 5. The method according to any one of the preceding claims, characterized in that that the plastic tape is cooled to a temperature at which its Shore hardness The Sbole hardness of the slide fastener tapes is the same. 6. Slide closure tapes for carrying out the method according to Claims 1 to 5, characterized in that the Gleitversdhlußbander on one the other side have a wide, flat fastening strip in which Incisions are provided which extend inwardly from the edge thereof and by which the fastening cord is subdivided into individual lobes, whose one another adjacent edges are in direct contact with one another. 7. Walls produced by the method of claims 1 to 5 for plastic casing tubes, characterized in that the side web of one of the slide closure tapes on the thin plastic tape to form a closed tube under the slide fastener tapes extending flap at a greater distance inward from the side edge of the same is attached. Printing documents considered: French patent specification no. 1,124,398; Standard sheet Din 1910, sheets 1 and 3, August 1954 edition.