DE102007044320B3 - Core-forming tool in tube or tubular shape for manufacturing inner contour of hollow body, particularly tube, has universal channel, in which medium is placed - Google Patents

Abstract

The core-forming tool (1) has a universal channel (3), in which a medium is placed. The core-forming tool consists of an elastic material. The core-forming tool is formed of successively arranged multiple core pieces (5) in direction of an axis (4), which lies together in an operating condition. The axis is marginally spaced together in a removing condition. The core pieces are connected by an elastically deformed and flexible hollow body (6).

Description

The The invention relates to a core tool in tubular and / or tubular form for producing an inner contour of a hollow body, in particular a pipe, wherein the core tool consists of an elastic material and with a consistent Channel is provided, in which a means is placeable.

Such Core tools are used to form the hollow body to be molded desired inner contour to give. In practice, however, it often proves problematic that the core tool is difficult to remove and the hollow body is not can be arbitrarily shaped.

Therefore At present, essentially only the gas internal pressure process (GIT / GID) used in the first a liquid Plastic is filled into the negative mold and after a short cooling time of the still liquid inner volume fraction is pressed out with water or gas pressure. It receives the inner wall, however, a rough contour. In addition, in this way close tolerances at the wall thickness not reliable be respected. As plastic is any thermoplastic, in particular PA.

Based on the internal gas pressure method is from the DE 696 15 114 T2 a method is known in which for producing the hollow body with the pressurized gas or fluid to a floating core, in particular in the form of a ball, is pressed through the negative mold.

As the core uses that from the DE 42 44 692 C1 known method air pressure for the production of hollow plastic molded parts. In this method, a tube is used as a core, which assumes a supporting function in a state inflated with compressed air during the shaping.

Following similar principles of internal support through an elastic tubular mandrel and / or core, the devices and methods employed by the DE 195 23 723 A1 and the DE 44 02 984 A1 are known.

Also the publication DE 26 39 833 C2 shows a mandrel for forming an inner contour of a hollow body in tubular and / or tubular form of an elastic material and having an interior, which is filled with a means, wherein the means is pressurized in a working condition and depressurized in a removal state. This mandrel is stiffened by an applied against its inner wall pressure and also extended transversely to the direction of the axis. The tubular mandrel assumes a straight running shape in the working state. A curved and / or curved course can not be realized with such a spike. To shape the hollow body, the mandrel must always be pressurized during the curing of the hollow body.

Of the Invention is based on the object, an easy to remove To create a core tool that is in a working state in axial Direction in a bow and / or curve-like course so determinable is that the distance to the outer mold is even and thus the wall thickness of the hollow body is not subject to fluctuations and that the core tool, without that the hollow body or damage the core tool, remove it from the hollow body leaves.

These Task is according to the invention with a Core tool according to the features of claim 1. The further embodiment of the invention is the dependent claims remove.

According to the invention is thus a core tool provided, consisting of several in the direction of the axis formed successively arranged core pieces, which in one Working state lie together and in a removal state to each other slightly spaced, wherein the core pieces by an elastically deformable and / or flexible enveloping body connected are. This makes it possible that the core tool is fixed in the working state and in the unloading state is flexible, with the core pieces be positioned at any angle to each other, whereby a simple and damage-free removal of the core tool from a nearly arbitrarily shaped hollow body possible is.

Advantageous is it that the enveloping body in the removal state opposite the working state in the direction of the axis stretched and the cross section of the envelope is reduced. In this way, the core tool can be easily removed in the removal position be because the envelope body of the shaped hollow body solves.

Farther It is advantageous that the core piece has at least one projection having, for engaging in at least one recess of the adjacent core member is trained. This makes it possible that the core pieces in the working state and are also axially guided in the spaced-apart removal position. The projection may, for example, have a rectangular cross-sectional shape, the flanks of which may be inclined.

It is equally favorable that the core pieces have axes which are inclined in the removal state and in the working state in the direction of the axis of the hollow body relative to each other. This makes it possible to a curved hollow body realize.

Cheap is it that the axes of the individual core pieces in the working state along a straight line are oriented. This makes it possible, straight hollow body manufacture. Such a core tool is particularly economical produce if all the core pieces are identical.

Advantageous it is that the envelope body the core pieces like a tube includes and with each one or just a single core piece of it Scope is firmly connected. This makes it possible that the individual core pieces in the Entnahmezustand are movable to each other and a direct power transmission parallel to the direction of the axis of the enveloping body on individual core pieces and / or all the core pieces possible is.

For circular Inner cross sections of the hollow body the use of a rotationally symmetrical core tool is possible. Along the direction of the axis, the cross section of the core tool should be consistent be. However, it is convenient that the core tool transverse to the direction of the axis corresponding to Internal cross section of the hollow body executable in any form is. This makes it possible to use hollow body point, mirror or asymmetric inner cross section with the core tool according to the invention manufacture.

From The advantage is that the material of the enveloping body is elastic and heat resistant. This makes it possible the core tool in usual injection molding use.

Farther is it cheap that the core tool is a centerpiece and / or has a closure body, by means of the patency of the running in the direction of the axis channel locally interrupted is. This makes it possible that the agent and / or a body, such as a fluid from which on the core pieces a Power exercised will only have to be influenced on one side.

It is according to the invention especially favorable that the agent is a pressure medium, in particular a liquid or a gas. This makes it possible that set at a pressurization of the agent of the removal state can be, because the medium between the core pieces and urges pushes them apart.

Cheap is it means that the agent in the working state of the core tool depressurized and is pressurized in the removal state of the core tool. This makes it possible that the core tool in the removal state, a defined outer shape has, without the observance of an exact pressure regulated must become.

Also it is advantageous that several means can be placed in the channel are and / or a means as a tensile body, in particular rope or Chain, executed is. This makes it possible that by applying the tensile body with a tensile stress in the working state the core pieces lie against each other so that the core tool has a high rigidity having.

The Invention leaves different embodiments to. To further clarify its basic principle is one of them shown in the drawing and will be described below. These shows in

1 a sectional view of a core tool;

2 a sectional view of a core tool in a working condition;

3 a sectional view of a core tool in a removal state;

4 a sectioned and enlarged view of a portion of the in 2 shown core tool in a working condition;

5 a sectioned and enlarged view of a portion of the in 3 shown core tool in a removal state.

1 shows a sectional view of a core tool 1 , The core tool 1 consists of several in the direction of an axis 4 successively arranged core pieces 5 through a flexible enveloping body 6 are connected. The envelope body 6 consists of an elastically deformable and heat-resistant material. The core pieces 5 and thus the core tool 1 are with one in the direction of the axis 4 extending continuous channel 3 Mistake. Every piece of the core 5 has a lead 7 and a recess 8th on, which are formed such that the projection 7 a centerpiece 5 into the recess 8th of the adjacent core piece 5 intervenes. The core tool 1 has a solid, rigid body in a working condition. These are the core pieces 5 positioned in working condition at an angle to each other and the projections 7 and recesses 8th interlock positively. This fixed position and positioning of the core pieces 5 and thus the core tool 1 is made possible by a force coming from the enveloping body 6 on the core pieces 5 of the core tool 1 is exercised. This will be the core pieces 6 pressed together. The channel 3 of the core tool 1 is filled with a remedy. In a removal state, this means is pressurized. It is possible that through the channel 3 a rope is performed, which in the working state by means of a pulling force to each other pressing the core pieces 5 strengthened. The axes 9 the individual core pieces 5 are at least in the working state substantially in the direction of the axis 4 of the hollow body 2 oriented.

2 shows a sectional view of a core tool 1 in a working condition. The illustrated embodiment of the core tool 1 in which the permeability of the channel 3 is broken, is in a multipart tool 10 positioned for injection molding. The tool is used 10 the shape of the outer shape of a hollow body 2 and the core tool 1 the shape of the inner shape of the hollow body 2 , In a working state of the core tool 1 is the channel 3 flooded or evacuated with a pressureless medium. Due to the lack of internal pressure is the of the enveloping body 6 on the core pieces 5 acting force so great that the core pieces 5 abut each other. The channel 3 is by means of a line 11 connected to a pressure generator. By using a closure body 12 is a connection to the pressure generator only one-sided necessary. The tool 10 can thus be designed in the region of the closure body in a simple manner.

3 shows a sectional view of the in the 1 and 2 described core tool 1 in a withdrawal state. The core tool 1 can after the manufacture of the hollow body 2 can be taken from this without the core tool 1 and / or the hollow body 2 to be damaged. According to the invention to the means in the channel 3 subjected to a pressure which exerts a force on the core pieces 4 which exercises against the power of the enveloping body 6 acts on the core pieces and is greater than the force of the enveloping body 6 , The pressure of the agent becomes the core pieces 6 spaced apart. The envelope body 6 that with the core pieces 5 connected is in the direction of the axis 4 stretched, resulting in a cross-sectional reduction of the envelope 6 transverse to the direction of the axis 4 leads. As a result, the enveloping body dissolves 6 from the inner surface of the hollow body 2 , The spaced core pieces 5 are not fixed in their relative position to each other and the forming of the core tool 1 from the hollow body 2 is thus possible in the removal state problem-free and without compensation.

4 shows a sectioned and enlarged view of a portion of the in 2 shown core tool 1 in a working condition. It can be seen that the core pieces 5 at least in a border area closed together. So are the core pieces 5 set in exactly one relative position to each other. Furthermore, the figure shows that the enveloping body 6 close to the hollow body 2 is applied. The hollow body 2 facing surface of the envelope 6 forms exactly the inner, ie the core tool 1 facing surface of the hollow body 2 from.

5 shows a sectioned and enlarged view of a portion of the in 3 shown and described core tool 1 in a withdrawal state. In comparison with the 4 is clear that the core pieces 5 are spaced. Since the elongation of the envelope body 6 with a reduction of the cross section of the enveloping body 6 goes along, is the envelope body 6 from the hollow body 2 detached and spaced to this. In this illustration, the recess can be 8th and the lead 7 which is a centerpiece 5 has, recognize well.

Claims (12)

Core tool ( 1 ) in tubular and / or tubular form for producing an inner contour of a hollow body ( 2 ), in particular a pipe, wherein the core tool ( 1 ) consists of an elastic material and with a continuous channel ( 3 ) in which a means is placeable, characterized in that the core tool ( 1 ) from several in the direction of the axis ( 4 ) core pieces ( 5 ) are formed, which lie in a working condition against each other and which are slightly spaced apart in a removal state, the core pieces ( 5 ) by an elastically deformable and / or flexible enveloping body ( 6 ) are connected. Core tool ( 1 ) according to claim 1, characterized in that the enveloping body ( 6 ) in the removal state relative to the working state in the direction of the axis ( 4 ) and the cross-section of the envelope ( 6 ) is reduced. Core tool ( 1 ) according to claims 1 or 2, characterized in that the core ( 5 ) at least one projection ( 7 ) for engaging in at least one recess ( 8th ) of the adjacent core ( 5 ) is trained. Core tool ( 1 ) according to at least one of the preceding claims, characterized in that the core pieces ( 5 ) Axes ( 9 ) in the removal state and in the working state in the direction of the axis ( 4 ) of the hollow body are inclined relative to each other. Core tool ( 1 ) according to at least one of the preceding claims, characterized in that the axes ( 9 ) of the individual core pieces ( 5 ) are oriented in the working state along a straight line. Core tool ( 1 ) according to at least one of the preceding claims, characterized in that the enveloping body ( 6 ) the core pieces ( 5 ) includes and with each or only a single core ( 5 ), in particular at its periphery, is firmly connected. Core tool ( 1 ) according to at least one of the preceding claims, characterized in that the core tool ( 1 ) transverse to the direction of the axis ( 4 ) corresponding to the inner cross section of the hollow body ( 2 ) is executable in any form. Core tool ( 1 ) according to at least one of the preceding claims, characterized in that the material of the enveloping body ( 6 ) is elastic and heat resistant. Core tool ( 1 ) according to at least one of the preceding claims, characterized in that the core tool has a closure body ( 12 ), by means of which the continuity of the in the direction of the axis ( 4 ) running channel ( 3 ) is interrupted locally. Core tool ( 1 ) according to at least one of the preceding claims, characterized in that the means is a pressure medium, in particular a liquid or a gas. Core tool ( 1 ) according to at least one of the preceding claims, characterized in that the means in the working state of the core tool ( 1 ) is pressureless and pressurized in the removal state of the core tool. Core tool ( 1 ) according to at least one of the preceding claims, characterized in that in the channel ( 3 ) a plurality of means are placeable and / or a means as a tensile body, in particular rope or chain, is executed.