EP1169170A1 - Method of producing a corrugated pipe which can be opened in the longitudinal direction and closed again - Google Patents

Abstract

The invention relates to a device (10) for producing a corrugated pipe (12) which can be opened in the longitudinal direction and closed again. To this end the corrugated pipe (12) is provided with a hooked profile (40) and a barbed profile (42) which both extend along in the length of the corrugated pipe (12). The device (10) comprises an extrusion die (14) and a corrugator (16) having first and second split-mould halves (18, 20) which along a common moulding line (22) constitute a moulding channel (32) for the corrugated pipe (12) to be produced. The first split-mould halves (18) are each provided with a radially stepped longitudinal cavity (48) presenting a first cavity (50) and an adjacent second cavity (52). The first cavity (50) serves to form the hooked profile (40) while the second cavity (52) receives an insert (54) which on its inner face (56) has a longitudinal channel (58) along which the barbed profile (42) is configured. The extrusion die (14) comprises a mandrel (78) with a plug (82). The plug (82) is advantageously configured such that it has a first raised part (92) which is assigned to the first cavity (50) and a second raised part (94) which is assigned to the longitudinal channel (58).

Description

Process for the production of a longitudinally slitable and reclosable corrugated tube

The invention relates to a device for producing a corrugated tube which is openable and reclosable in its longitudinal direction and has a hook profile running in its longitudinal direction and an adjacent, parallel barb profile, with a spray head and a corrugator with first and second mold jaw halves which can be moved simultaneously along two endless tracks and which lie closely together with their end faces along a common molding section and form a molding channel for the corrugated tube between them.

A corrugated tube of the type mentioned above for the protective sheathing of electrical lines with a slot-shaped opening running along a surface line of the corrugated tube, the edges of which have closure elements with a hook profile and a barb profile, which temporarily close the longitudinal slot, is known from DE 19641 421 A1. This known corrugated pipe consists of an elastic plastic material. The closure elements join to form a closure as soon as pressure acts on the corrugated pipe. The locking elements slide over each other and get caught together. The closing elements are held in the closed position when no more pressure is exerted on the corrugated pipe. This is achieved by the mechanical tension previously introduced into the corrugated tube by the pressure. A device for producing this known corrugated tube is not described in the cited document.

From DE 197 05 761 A1 a corrugated plastic tube with a longitudinal slot or with an essentially continuous opening extending in the longitudinal direction of the corrugated plastic tube is known, the opposite edge regions of the longitudinal slot being designed at least in sections such that they can be connected to one another. A similar corrugated plastic tube is known from WO 97/32 379.

DE-PS 22 61 530 describes a freely routable flexible insulating tube of any length made of plastic, which contains at least two electrical lines which are insulated from one another by corresponding coatings and which only partially fill the clear tube cross section of the insulating tube. The insulating tube is a known, flexible pleated or corrugated tube. The plastically flexible, insulated electrical cables are loosely arranged in the corrugated or corrugated pipe and are sufficiently rigid to allow the pleats to be folded after bending. Keep corrugated tube in the curved shape. From this last-mentioned document, a device for producing such a corrugated tube is also known, which has a spray head and a corrugator with first and second mold jaw halves, which form a molding channel for the corrugated tube along a common molding path. From DE-OS 21 02420 a sheath made of plastic, in particular for cables, is known, which has a longitudinal slot, which can preferably be closed by means of a liquid-tight slide closure. This cladding tube is characterized in that it consists of an inner tube with a corrugated wall made of relatively hard plastic in the circumferential direction and an outer or jacket tube made of a relatively soft plastic that adheres to the inner tube and is at least approximately smooth in the circumferential direction. The jacket or outer tube carries the closure elements of the liquid-tight slide closure.

From DE 32 46 594 A1 a corrugated corrugated tube made of plastic is known, which is provided for electrical installation purposes and which is designed for this purpose with a longitudinal slot. Along the longitudinal slot a snap-snap locking device is provided detachably connecting the two slot edges. A device for producing such a corrugated tube is not described in this document.

DE 34 05 552 A1 discloses a thin-walled, cross-corrugated, longitudinally slotted plastic protective tube for receiving electrical lines. On both sides of the longitudinal slot, mutually opposite and mutually complementary indentations and / or bulges are arranged, which can be placed on top of one another and, in particular, brought into engagement with each other like a push button. Along the slot are wart-like protuberances divided by the slot, which protrude beyond the outer contour of the tube and can be decapitated to lead through the lines or a line branch to form an opening leading to the inside of the tube. DE-AS 17 04 718 discloses a device for the production of double-walled plastic pipes with an annular or helically grooved outer wall and a smooth inner wall with a spray head which has two ring nozzles from which two concentric pipes are extruded in one operation. The two ring nozzles are fed from two separate, independently controllable extruders. This known device has a mandrel with a mandrel extension, the outer diameter of which corresponds to the inner diameter of the pipe to be produced. The mandrel extension is formed with a cylinder section that defines a

Outside diameter. This defined outer diameter corresponds to the desired inner diameter of the double-wall pipe to be produced.

The invention has for its object to provide a device which is suitable for the precise production of openable and reclosable corrugated pipes of the type mentioned with high productivity.

This object is achieved according to the invention in a device of the type mentioned at the outset in that the first mold jaw halves are each formed with a radially stepped longitudinal recess which is a first

Has recess and a second recess, the first recess is adapted to form the hook profile to the radial depth of the transverse shafts and the second recess is adjacent and recessed in the circumferential direction to the first recess, wherein an insert is provided in the recessed second recess has a longitudinal channel on its inner end face to form the barb profile. The first mold jaw half with the radially stepped longitudinal recess, ie with the first recess and with the second recess adjoining it, can be produced simply and precisely in a time-saving manner. The production of the insert with the longitudinal channel is also simple, time-saving and precise, so that there is an overall advantage that the first mold jaw halves of the device according to the invention can be realized exactly inexpensively.

In order to achieve reliable hooking of the barb profile with the hook profile of the corrugated tube produced with the device according to the invention, it is preferred if the longitudinal channel formed on the inner end face of the insert has an undercut barb surface and a wedge surface which engages with the barb surface in the interior of the includes the first mold jaw half widening acute angle. A longitudinal channel designed in this way can be simply and precisely manufactured in the respective insert before the insert is then fixed in the recessed second recess of the first mold jaw half. This fixation can be done, for example, by screwing.

So that not only the barb surface but also the associated hook surface of the hook profile of the corrugated tube produced with the device according to the invention forms an undercut with a simple design, it has proven to be expedient if the first recess and the parallel main surfaces have an insert with respect to the end surface the first mold jaw vertical plane of symmetry asymmetrical, ie are provided off-center. Taking into account the wall thickness of the corrugated tube to be produced or produced with the device according to the invention or in particular the hook and barb profile running in the longitudinal direction of the corrugated tube, it is expedient if the longitudinal channel formed in use has a depth which is less than the depth of the transverse waves. It serves the same purpose if the inner end face of the insert is divided by the longitudinal groove into a first and a second partial end face, the first partial end face being continuously connected to the adjacent end of the transverse shaft inner contour and the second partial end face being radially offset against the first partial end face is offset outside. This radial offset of the second partial end face against the first partial end face is expediently adapted to the wall thickness of the corrugated tube or its longitudinal hook and barb profile.

It has proven to be particularly advantageous if, in the device according to the invention, the spray head protruding into the molding channel has a mandrel which is formed at its distal end with a stopper which has a first and a second elevation which extend from one another in the circumferential direction of the stopper are spaced apart so that the first elevation of the first recess provided for forming the hook profile in the first mold jaw half and the second elevation of the longitudinal channel provided for forming the barb profile is assigned in use. Independent patent protection is sought for this last-mentioned design of the device according to the invention. It has been shown that the flow of the plastic material through the spray head into the mold channel of the corrugator is optimized by such a design, so that with high productivity Precise corrugated tubes with a longitudinal hook and barb profile can be produced. The mold channel of the corrugator can be subjected to an external vacuum and / or an internal pressure in order to nestle the plastic material emerging from the injection head along the molding path to the mold channel of the first and second mold jaw halves.

Further details, features and advantages result from the following description of an embodiment of the device according to the invention shown schematically in the drawing or of essential details thereof, as well as a corrugated tube produced with this device. Show it:

FIG. 1 shows a schematic representation of an embodiment of the device for producing a corrugated tube with a spray head and with a corrugator,

2 shows a corrugated tube produced with the device according to FIG

Cross-section,

Figure 3 in a cross-sectional view similar to Figure 2, the corrugated tube after the longitudinal slitting and reclosing the

Longitudinal slot,

Figure 4 shows a longitudinal section through an embodiment of the spray head

1,

Figure 5 is a front view of a first and a second mold jaw half 1 on the common molding section to form a molding channel for the corrugated tube,

Figure 6 on an enlarged scale the detail A in Figure 5 to illustrate the corresponding profile section of the first

Mold jaw half,

FIG. 7 shows detail B according to FIG. 5 on an enlarged scale

Clarification of the corresponding section of the first mold jaw half and the use combined therewith,

Figure 8 is a view of the first mold jaw half in the direction of the arrows

VIII-VIII in Figure δ,

FIG. 9 shows an end view of the insert according to FIG. 7,

FIG. 10 shows a view of the insert in the direction of arrow X in FIG. 9 on one of its two main surfaces,

FIG. 11 shows a view of the second mold jaw half in the direction of the arrows Xl-Xl in FIG. 5,

Figure 12 is an enlarged view of the detail C in Figure 11, and

FIG. 13 shows a section along the section line Xlll-Xlll in FIG. 4 through the stopper provided at the distal end of the injection head mandrel Spray head in combination with the corrugated tube indicated by thin dash-dotted lines - similar to the cross-sectional profile of the corrugated tube shown in FIG.

Figure 1 shows schematically an embodiment of the device 10 for producing a corrugated tube 12, as shown in cross section in Figure 2. The device 10 has a spray head 14, as will be described below in connection with FIG. 4. The device 10 also has a corrugator 16 with first mold jaw halves 18 and with second mold jaw halves 20, of which only a few are indicated schematically in FIG. 1, namely along the mold channel 22. The first mold jaw halves 18 run along an endless path 24. The second mold jaw halves 20 run along an endless path 26. The first and second mold jaw halves 18 and 20 lie closely against one another with their end faces 28 and 30 along the common molding section 22 and form a molding channel 32 for the corrugated tube 12 to be produced from a suitable plastic material.

FIG. 2 shows in cross section an embodiment of the corrugated tube 12 made of plastic material which has transverse shafts 34 which extend in the circumferential direction and are equidistantly spaced axially from one another. The transverse shafts 34 are not self-contained, but each end on a first end face 36 and on a second end face 38. A hook profile 40 of the corrugated tube 12, which extends in the longitudinal direction of the corrugated tube 12, adjoins the second end face 38. The corrugated tube 12 also has a barb profile 42 spaced apart from the hook profile 40 in the circumferential direction, which extends like the hook profile 40 in the longitudinal direction of the corrugated tube 12. Between the hook profile 40 and the barb profile 42, the corrugated tube 12 is formed with an outwardly open longitudinal channel 44, along which the corrugated tube 12 can be slit longitudinally or is slit longitudinally on site. This longitudinal slitting is indicated in FIG. 2 by the two arrows 46 facing each other. After the longitudinal slitting of the corrugated tube 12, the two longitudinal edges of the corrugated tube 12 are moved together in such a way that the barb profile 42 hooks into the hook profile 40 in order to close the longitudinally slotted corrugated tube 12 again. This reclosed state of the corrugated tube 12 is shown in the drawing in FIG. 3.

The first are for the precise production of the corrugated tube 12 according to FIG

Mold jaw halves 18 each formed with a radially stepped longitudinal recess 48 (see FIGS. 5 to 8). In particular, FIG. 7 clearly shows the stepped longitudinal recess 48 with a first recess 50, which is provided for forming the hook profile 40 of the corrugated tube 12, and with a recessed second recess 52, which is adjacent to the first recess 50 in the circumferential direction and is used for receiving and fastening a Insert 54 (see also Figures 9 and 10) is provided. The insert 54 has on its inner face 56 a longitudinal groove 58 which is used to form the barb profile 42. The longitudinal groove 58 is formed with an undercut barb surface 60 and with a wedge surface 62. The undercutting barb surface 60 encloses an acute angle with a plane of symmetry 64 perpendicular to the end surface 30 of the first mold jaw half 18. The wedge surface 62 encloses with the undercutting barb surface 60 an acute angle that widens into the interior of the first mold jaw half 18. As can be seen from FIGS. 5 to 7, the first recess 50 and the insert 54 with the longitudinal groove 58 for forming the hook profile 40 and the barb profile 42 of the corrugated tube 12 are asymmetrical with respect to the plane of symmetry 64 perpendicular to the end face 28 of the respective first mold jaw half 18, ie provided laterally offset in the circumferential direction.

The longitudinal channel 58 formed in the insert 54 has a depth starting from the inner end face 56, which is smaller than the radial depth of the transverse shafts 34 of the corrugated tube 12 or the transverse shafts 66 of the respective first mold jaw half 18. This ensures that the barb profile 42 can hook with the hook profile 40 (see FIG. 3), the barb profile 42 being positioned in the clear interior of the hook profile 40. It serves the same purpose if the inner end face 56 of the insert 54 is divided by the longitudinal groove 58 into a first partial end face 68 and into a second partial end face 70, the first partial end face 68 at the adjoining end 72 of the inner contour 74 of the transverse shafts 66 of the first Mold jaw half 18 connects continuously, as can be seen, for example, from FIG. 6. The second partial end face 70 is offset radially outward against the first partial end face 68, so that - as can be seen from FIG. 3 - the barb profile 42 and the hook profile 40 do not interfere in the radial direction when the corrugated tube 12 is closed again.

FIG. 4 shows in a longitudinal section an embodiment of the spray head 14 with a mouthpiece 76 which projects into the molding channel 32 of the corrugator 16 of the device 10 (see FIG. 1). The mouthpiece 76 has a central mandrel 78. The mandrel 78 is formed at its distal end 80 with a plug 82 through an annular slot 84 is determined through which the plastic material to be extruded for the production of the corrugated tube 12 exits into the molding section 22 of the corrugator 16. The ring slot 84 is connected via a channel 86 to a plastic extruder, not shown. The mandrel 78 is formed with a central through-channel 88, which is connected in terms of flow technology to a connecting element 90. The connecting member 90 serves, for example, to connect a compressed air source in order to extract the extrutate emerging from the ring slot 84, ie plastic material in the molding channel 32 of the corrugator 16 of the device 10 (see FIG. 1) against the inner surface of the molding channel 32 determined by the mold jaw halves 18 and 20 to align and form the corrugated tube in the form channel 32.

As can be seen from FIG. 13, the stopper 82 formed on the distal end 80 of the dome 78 is formed with a first elevation 92 and with a second elevation 94 spaced apart therefrom in the circumferential direction. The

Elevations 92 and 94 are designed, for example, as ribs, which extend in the axial direction of the plug 82. The elevations 92 and 94 are spaced apart from one another in the circumferential direction of the plug 82 such that the first elevation 92 is assigned to the first recess 50 for forming the hook profile 40 of the corrugated tube 12 and the second elevation 94 is assigned to the longitudinal channel 58 for forming the barb profile 42 of the corrugated tube 12 . Through the elevations 92 and 94 on the plug 82 of the dome 78 is reliably achieved in a simple manner that the corrugated tube 12 is realized precisely with high productivity not only in the region of its transverse shafts 34 but also along the hook and barb profile 40 and 42 with a defined wall thickness can be. The same details are given the same reference numerals in FIGS. 1 to 13.

Claims

Expectations: 1.Device for producing a corrugated tube (12) which is openable and reclosable in its longitudinal direction and has a hook profile (40) running in its longitudinal direction and an adjacent parallel barb profile (42), with a spray head (14) and a corrugator (16) with the first and second mold jaw halves (18 and 20) which can be moved simultaneously along two endless tracks (24 and 26) and which lie closely against one another with their end faces (28 and 30) along a common molding path (22) of the two tracks (24 and 26) and form between them a shaped channel (32) for the corrugated tube (12), characterized in that the first shaped jaw halves (18) each have a radially stepped Long recess (48) are formed, which has a first recess (50) and a second recess (52), the first recess (50) for forming the hook profile (40) to the radial depth of the transverse shafts (66) of the first mold halves ( 18) is adapted and the second recess (52) is adjacent and recessed in the circumferential direction to the first recess (50), wherein in the recessed second recess (52) an insert (54) is provided which has a longitudinal channel (58) on its inner end face (56) to form the barb profile (42) of the corrugated tube (12). 2. Apparatus according to claim 1, characterized in that the longitudinal groove (58) on the inner end face (56) of the insert (54) has an undercut barb surface (60) and a wedge surface (62) which with the barb surface (60) one includes an acute angle widening into the interior of the first mold jaw half (18). 3. Device according to claim 1 or 2, characterized in that the first recess (50) and the insert (54) with respect to the perpendicular to the end face (28) of the first mold jaw half (18) Plane of symmetry (64) are provided asymmetrically. 4. Device according to one of claims 1 to 3, characterized in that the longitudinal channel (58) in the insert (54) has a depth which is less than the depth of the transverse shafts (66) of the first mold jaw halves (18). 5. Device according to one of claims 1 to 4, characterized in that the inner end face (56) of the insert (54) divided by the longitudinal groove (58) into a first partial end face (68) and a second partial end face (70) The first partial end face (68) adjoins the adjoining end (72) of the inner contour (74) of the transverse shafts (66) and the second partial end face (70) is offset radially outward from the first partial end face (68). 6. The device in particular according to one of the preceding claims, characterized in that the spray head (14) projecting into the molding channel (32) of the corrugator (16) has a dome (78) which has a plug (82) at its distal end (80) ) is formed, the first and a second Has elevation (92 and 94) which are spaced apart in the circumferential direction of the plug (82) such that the first elevation (92) of the first recess (50) provided for forming the hook profile (40) of the corrugated tube (12) in the first Mold jaw half (18) and the second elevation (94) of the longitudinal channel (58) provided for forming the barb profile (42) in the insert (54) is assigned.