DE20320348U1 - Calibration unit for endless extruded profiles, comprises numerous lamina crown sections composed of individual elements, with an inner opening - Google Patents

Abstract

A calibration unit for calibrating endless extruded profiles, esp pipes, comprises numerous lamina crown sections composed of individual elements (18), which have an inner opening that forms the calibration opening. A calibration unit for calibrating endless extruded profiles, esp pipes, comprises numerous lamina crown sections composed of individual elements (18), which have an inner opening that forms the calibration opening. The elements are arranged one behind the other to form a segment block (16). The individual elements are coupled together, and the individual segment blocks are located in a housing (12,14) so axially neighbouring segments overlap. Each segment block has an activating unit (20) which holds the individual blocks in the housing. The inner ends of some of the elements have rollers (74) whose surfaces are parallel to the rotational axes of the corresponding segment sections, and concave. The curvature of the surfaces corresponds to the largest diameter adjustment of the calibration unit. The rollers have a holder located in the segment block.

Description

The ending relates to a calibration device for Calibration of extruded endless profiles, especially pipes, comprising a calibration basket with an adjustable calibration diameter, according to the generic term of claim 1.

Calibration facilities are, for example for the calibration of extruded endless profiles, especially pipes, used. First, a plastic melt is produced in an extruder processed, which is shaped by an outlet nozzle becomes. To ensure the desired Dimensioning of the endless profile, this goes through after shaping the calibration device in which it is calibrated with dimensional accuracy.

In the manufacture of plastic pipes until a while ago it was necessary for different wall thicknesses or outside diameter to provide various calibration facilities. To do this the tools are replaced, resulting in a machine shutdown required and thus led to downtimes.

In the DE 198 43 340 C2 it is therefore proposed to use an adjustable calibration device for different pipe dimensions. This calibration device consists, for example, of a multiplicity of lamellae which are distributed on the outside of the tube to be calibrated over the circumference and are arranged at a distance from one another. Seen in the direction of production of the tube, a large number of such lamellar rings are arranged within a calibration station, the individual lamellas of the individual lamellar rings being in a gap with respect to one another, whereby a problem-free adjustment of the individual lamellas of the individual ring is possible with respect to the lamellas of the subsequent ring or the previous ring , The slats are segmented into a slat block and supported by a support structure. The holding structure is in turn connected to the housing in a radially adjustable manner.

Between the inner surfaces of the slats and the Continuous profile to be calibrated (e.g. pipe) occurs in the known State of the art sliding friction. Due to the multitude of Slats - both in the circumferential direction as well as in the axial direction - this sliding friction adds up such that - especially with huge Pipe diameters - pulling forces in the ton range are necessary.

Object of the present invention is to provide a calibration facility where you can can get by with a relatively low pull-off force.

This task is claimed by the 1 specified features solved.

A basic idea of the present Invention is a sliding friction through the use of rollers at the inner end of elements that together form the calibration opening, to avoid. For each role, the sliding friction is then replaced by a replaced much smaller rolling friction. Overall this leads to the fact that you need much smaller pull-off forces.

The roles have a rotationally symmetrical Surface shape, which is essentially complementary to the endless profile, in particular tubular profile, is formed. In particular are their surfaces parallel to their axis of rotation corresponding to a segment of a circle segment the calibration opening concave and their axis of rotation are each perpendicular to the deduction direction of the endless profile arranged such that the endless profile during the calibration process on the inside surfaces of the Rolls.

According to a particularly preferred embodiment corresponds to the curvature the surface parallel to the direction of rotation the largest diameter of the calibrated Endless profile.

A particularly low rolling friction let yourself through the use of needle roller bearings. Of course you can too other types of bearings can be used.

The rollers can each be attached to a bracket be inserted into a segment block or on a segment block to be ordered. This means that the roller units can be separated manufacture and insert into a uniformly produced segment block, which enables a fairly simple assembly.

The ending is referenced below explained in more detail on the accompanying drawings. The drawings show in:

1 1 shows a schematic sectional illustration of a conventional embodiment of a calibration device according to the invention perpendicular to the production direction of a tube,

2 : a calibration device according to the invention as in 1 in a schematic partial sectional view parallel to the production direction with rotating device,

3 : a schematic representation of a conventional segment block with lamella inserts as in the 1 and 2 used

4 : a schematic representation of a segment block according to the invention with rollers arranged on the inside and

5 : a schematic representation of roller inserts as in the embodiment of 4 used.

A complete arrangement of a device for producing a plastic tube including extruder, vacuum device and calibration basket can be found in the DE 198 43 340 C2 be removed. An already adjustable calibration basket is shown in this. In the DE 198 43 340 C2 a pipe extrusion system is shown schematically. At the beginning of such a pipe extrusion plant there is a Extruder, into which a pipe raw material is filled, melted and finally discharged. The melt produced in the extruder then passes through a pipe tool, in which it is brought into the required pipe shape. In this case, the pipe tool is a changeable pipe tool, so that the pipe outlet gap can be adjusted in accordance with the diameter and wall thickness requirements. A thermoplastic melt hose emerges from the pipe tool, which is then introduced into a vacuum tank calibration with a calibration device. The vacuum tank calibration consists of a cooling tank which can be closed in a vacuum-tight manner and in which - not shown in detail - spray nozzles are provided for cooling the melt hose. The calibration basket for the final shaping of the melt hose, which is described in more detail below, is arranged in the vacuum tank calibration. Due to a pressure difference between the normal pressure inside the pipe and the negative pressure in the vacuum tank, the melt hose is pressed onto the calibration basket.

After the vacuum tank calibration, in which already a first cooling can take place the tube hose another cooling device, in which also by means of water baths or spray nozzles is cooled. In this cooling device the pipe is cooled down so far that it is for subsequent stresses are dimensionally stable.

After the cooling device usually follows a take-off device which continuously feeds the melt hose and pressure-free and at a constant speed through calibration and the cooling tanks draws. The pull-off force of the system must be greater than that which occurs Frictional forces. A common A type of deduction is caterpillar deductions.

After the trigger device, a The hose is cut in a separator, see above that pipes of equal length are producible, which are then placed on a storage table and by a deposit there supplied become. Alternatively, the extruded tube can also be rolled up continuously become.

The adjustable calibration basket is a core component of a pipe extrusion system with the possibility of changing dimensions. He takes over The shaping task of a standard calibration can, however, be done via the infinitely adjustable diameter range due to the design become.

This adjustment is made possible by the fact that the surface adjacent to the tube is formed by a large number of individual segments. In the 1 shown segments 18 have a curvature along the circumferential direction of the pipe, which corresponds to the largest possible pipe outer diameter and are combined to form individual segment rings. These segment wreaths are spaced apart as seen in the direction of production, but they lie closely behind one another. Two consecutive segment wreaths are combined to form a dimension wreath, which are staggered to each other. This ensures that there are no gaps or spaces between circumferentially adjacent fins when the tube passes through the calibration basket. The individual segment surfaces together form an essentially smooth inner tube surface with an essentially circular geometry (stronger polygonal design for small diameter settings).

The segments lying axially one behind the other in the production direction of the tube 18 are over a support structure to a segment block 16 summarized. The support structure is connected to an actuating device which blocks the respective segment 16 connects in a radially adjustable manner to the housing of the calibration basket. In the present exemplary embodiment, the housing of the calibration basket consists of two cylinder sections arranged coaxially one inside the other 12 and 14 , In these cylinder sections 12 . 14 are the individual segment blocks 16 recorded in a circle.

As in 3 can be seen include the segment blocks known per se 16 slats arranged one behind the other 18 , which are attached to two support rods. The support rods form a support structure. In turn, two spindle supports with externally threaded sections are arranged on the support rods, spaced apart in the axial direction.

In the case of a fully assembled calibration device, the external thread sections are in the associated bores of the housing cylinder 12 and 14 added. Between the two housing cylinders 12 and 14 is a gear nut for each external thread section 22 provided that cooperates with the external thread of the external thread section in an adjustable manner (cf. 1 and 2 ).

Perpendicular to the production direction of the pipe 24 are present 12 Segment blocks arranged in a circle (cf. 1 ). Each segment block has two spindle supports 20 that are axially spaced ( 2 ) and each with an associated gear nut 22 interact. The gear nuts 22 turn through a gear ring 26 which is circumferentially between the axially spaced gear nuts 22 stretches, adjusted together. For this purpose, the gear ring has 26 on both edges with the gear nuts 22 intermeshing teeth. The gear ring also has teeth on the outer circumference, with which it interacts with a toothed belt.

By actuating the gear ring 26 relative to the gear nuts 22 all segment blocks can be adjusted radially outwards or inwards in the same way. If all segment blocks are adjusted radially in the same way, the calibration diameter changes. The outer diameter of the raw part to be calibrated can be adjusted in the area of the adjustment facility res 24 define.

A disadvantage of the above However, the construction is the relatively high sliding friction on the inner surface of the individual slats. This leads - as mentioned above mentioned - especially with large pipe diameters to necessary pull-off forces in Ton range.

It is therefore proposed according to the invention to avoid sliding friction and to replace it with a smaller rolling friction. An embodiment of how this can be implemented constructively is in the 4 and 5 shown. The segment block 50 in 4 replaces the segment block 3 and can instead be in the case 12 . 14 the calibration device. On the segment block 50 a plurality of individual roles are arranged on the inside instead of the individual slats, one role in 5 is shown. Here is the body of the segment block 50 constructed essentially in one piece, for example molded from metal or made from relatively strong and heat-resistant plastic.

In this segment body are on the inside of the calibration device - that is, to form the calibration opening, a plurality of roller inserts 68 inserted one behind the other in the axial direction.

The roller inserts 68 consist of a holding and storage part 70 , which can be punched out of sheet metal, and the roll 74 itself. The role 74 is by means of a needle bearing on the holding and bearing part 70 kept low rolling friction. The holding and storage part 70 has two holes in its upper area 72 for fixation in the body of the segment block 50 on.

When assembling the upper tab-like projections of the holding and bearing parts 70 in corresponding grooves in the segment block 50 used and over the holes 72 fixed.

At the - in 5 shown below - surface of the roll 74 runs the endless profile to be calibrated. When manufacturing pipes, the surface corresponds to the roll 74 in the circumferential direction of the pipe to be calibrated, therefore a segment of a circle, preferably the largest calibration opening that can be set in the device.

Overall, the present Invention the pull-off force by using rollers for the calibration opening significantly to reduce. moreover the calibration device can also be easy to install and relative economical getting produced. Naturally are other embodiments of the present invention possible. It is only essential that the high sliding friction in the calibration opening is replaced by a lower rolling friction.

10

calibrating

12

outer housing cylinder

14

internal housing cylinder

16

segment block

18

slats

20

spindle carrier

22

gear nut

24

To calibrating tube

26

gear ring

30

holding rods

40

Externally threaded rod

52

lamellar Elements with roles

68

Castor inserts

70

holding and bearing part

72

mounting holes

74

roll

76

needle roller bearings

78

Segmented surface

Claims (4)

Calibration device for the calibration of extruded endless profiles, in particular pipes, comprising a large number of individual elements ( 18 ) existing lamellar rings arranged one behind the other, the inner surface of which together form a calibration opening, with elements lying one behind the other in the axial direction ( 18 ) to a segment block ( 16 ) are summarized, - the individual elements ( 18 ) of each segment block ( 16 ) are coupled with each other, - the individual segment blocks ( 16 ) essentially circular in such a way in a housing ( 12 . 14 ) that axially adjacent segments ( 18 ) partially overlap in each position in the circumferential direction, and - each segment block has at least one actuating device ( 20 ) with which the individual segment blocks ( 16 ) in the housing ( 12 . 14 ) and an adjustment of each individual segment block ( 16 ) can be carried out in the radial direction, characterized in that at the inner end of at least some elements ( 18 ) Roll ( 74 ) are arranged, the surface ( 78 ) are curved in a rotationally symmetrical concave manner parallel to the axis of rotation corresponding to a segment of a circle of the calibration opening and the axis of rotation of which is arranged perpendicular to the withdrawal direction of the endless profile in such a way that the endless profile on the inside surfaces of the rollers during the calibration process ( 74 ) rolls. Calibration device according to claim 1, characterized in that the curvature the surface of the largest diameter setting corresponds to the calibration device. Calibration device according to claim 2, characterized in that the rollers ( 74 ) on a bracket ( 70 ) are needle-bearing. Calibration device according to one of claims 2 or 3, characterized in that the holder ( 70 ) in the segment block ( 16 ) can be used.