GB2229950A

GB2229950A - Drawing drum

Info

Publication number: GB2229950A
Application number: GB9005635A
Authority: GB
Inventors: Ing Gerhard Henreich; Dipl Ing Walter Steinberg
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1989-03-13
Filing date: 1990-03-13
Publication date: 1990-10-10
Anticipated expiration: 2010-03-13
Also published as: GB9005635D0; DE3908524C1; GB2229950B

Description

1 1 A DEVICE FOR DRAWING STRANDLIKE MATERIAL, CHIEF1,Y C'OPPER MBTNG The

invention relates to a device for drawing strand-like material, such as copper tube, comprising a drawing drum which applies the necessary drawing force and which rotates about a vertical axis of rotation, a clamp which grips the end of the drawn material and is arranged on the outer surface of the drawing drum, and an annular disc arranged above the clamp, the disc engaging round the drum and being driven in the same direction and at the same speed as the drum. and being mounted obliquely in relation to the plane of the drum in order to dislocate the drawn turns, where the diameter of the annular disc about which the latter is pivoted into an oblique position extends at right angles to the diameter of the drum which itself extends through the meeting point of the tube with the drum and through the axis of rotation thereof.

To allow the drawing of particularly small, thin-walled tubes of long length in a technically simple and economical fashion, drum drawing machines (spinner blocks) were developed which comprise a driven draw.,ng drum with a clamp arranged at the periphery which grips the end of the material being drawn. Firstly a few turns are wound onto the drawing drum which transmit the necessary drawing force when the material has been broken off in the region of the clamp. Above the clamp, obliquely to the drawing drum is arranged a disc which continuously slips the turns along the drawing drum. Such machines permit the drawing of theoretically endless tubes which are generally drawn from one container into another.

In the known machines the so-called slip edge is formed by an annular disc which is mounted separately and rotates in the same direction and at the same speed as the drawing drum without changing its oblique position. The oblique position of the annular disc is determined by the maximum drawn tube diameter; this is because the drawn tube, which winds on to the drum at the highest point of the annular disc, is pressed down on half the drum periphery as a result of the oblique positioning of the disc on the drawing drum. On the second half of the drum periphery the tube maintains its achieved 2 position so that the annular disc no longer has contact wit-h the tube. When the drum rotateS the turn of the tube is located one tube diameter lower than the incoming tube.

It has been proved that in the drawing of thin tubes, for example in the diameter range of 4 mm and less, the tube can be compressed in the gap remaining between the drawing drum and the annular disc, leading to disturbances. The gap is formed by the oblique position of the annular disc, the circular-ring-shaped inner diameter of which appears elliptical when projected in the direction of the axis of rotation of the drum so that at two oppositely located points the annular disc has a very narrow gap and at the respective points offset by 900 it has a very wide gap. The size of the gap cannot be as small as is desirable because of production tolerances of the numerous fits, non-circularity of drum and annular disc, angular deviations of the annular disc and temperature differences between the drum and the annular disc.

It has been recognised as disadvantageous that the gap is greatest at precisely that point at which the dislocation of the small diameter tube must take place, at approximately 900 after the point where the drawn tube runs on to the drum, and a jamming of the small diameter tube between the drum and annular disc can take place here.

Commencing from the recognised problems and disadvantages, the present invention aims to prevent the jamming of the tube during the dislocation process between the annular disc and the drum surface without the need to change the oblique angle of the annular disc governed by the largest tube diameter.

For the realisation of this aim it is proposed in accordance with the invention that the axis of rotation of the annular disc is offset relative to the axis of rotation of the drum on the horizontal diameter of the disc in opposition to the incoming direction of the material to be drawn.

In a structurally simple fashion the proposal of the invention provides that the oblique annular disc be offset relative to the drum in such manner that the gap between the annular disc and 3 the drum is kept as narrow as possible in the region where the tube is to be dislocated. The fact that the gap between the drum and the annular disc is thereby increased in size on the opposite side is not disadvantageous because, as stated in the introduction, in any event the tube no longer contacts the annular disc at this point.

It has proved particularly favourable also to offset the annular disc along the diameter about which it is rotated into an oblique position relative to the axis of rotation of the drum in the direction of the meeting point of the drawn material with the drum. As a result of this proposal the narrowest gap is between 90 and 1800 after the point where the drawn material runs on to the drum, so that at 90 and 1800 the gap is approximately equal in size.

In a favourable development of the invention it is provided that the displacements of the axis of rotation of the disc relative to the axis of rotation of the drum and of the diameter of the disc relative to the axis of rotation of the drum are adjustable.

The necessary adjustment is in the region of a 1/10th of a millimetre. For the operation of the drum drawing machine a central positioning of the annular disc relative to the drawing drum is unnecessary. The adjustment of the annular disc can take place using pressure screws, cam- type eccentric pressure components, or wedge-shaped pressure components and is left to the discretion of the constructor.

An exemplary embodiment of the invention will now be described with reference to the accompanying drawing, in which:

Figure 1 is a schematic diagram of a drum drawing machine of the spinnerblock type; Figure 2 is a section through the drawing drum and annular disc. in the plane A-A of Figure 1; Figure 3 illustrates the geometric conditions of the gap between the annular disc and the drum corresponding to the prior art; and

Figure 4 illustrates the geometric conditions of the gap between the annular disc and the drum corresponding to the invention.

4 Figure 1 is a rough simplificatiqn of a drum drawing machine of the type described in the introduction, in the machine frame 1 of which the drum 2 is pivotally mounted. Also mounted in the machine frame 1 at 4 is the annular disc 3 which, as can be seen from the drawing, is inclined relative to the axis of rotation 5 of the drawing drum 2. Adjustment means for the annular disc 3 which will be described later in the description are indicated at 6.

The tube emanating from the drawing tool (not shown) runs on to the drum 2 at 7 and during the rotation of the drum 2 and the annular disc 3 is slipped downwardly by the latter so that in the front part of the drum 2 as seen in the Figure the tube R no longer contacts the annular disc. Instead the tube turn extends horizontally in this region so that above this tube turn a space is available for the incoming tube 7. When the drum 2 has been encircled several times, the tube being retained by pressure rollers 8, the respective lowest turns fall into the container 9 below the drum 2. Thus far the principle of the drum drawing machine corresponds to the spinner block construction mode.

In Figure 2 which is a section A-A of Figure 1, it can be seen that the annular disc 3 is offset relative to the axis of rotation 5 of the drum 2 in accordance with the invention. The axis of rotation of the annular disc is referenced 11.

As a result of the offset of the annular disc 3 relative to the drum 2 in the upper region between the annular disc 3 and the drum 2 as seen in the Figure, a smaller gap occurs than in the lower region. Preferably the narrowest gap occurs at 12. This ensures that the tube running on to the drum at 7 is not drawn into the gap between the drum 2 and the annular disc 3 but is correctly slipped down.

The invention will be explained in the following making reference to Figures 3 and 4.

Figure 3 is a schematic diagram of the previous arrangement in which the inner ring 13 represents the outer diameter of the drum 2 and the outer ring 14 represents the inner diameter of the annular disc. By virtu of the fact that the annular disc 3 is arranged obliquely relative t -1, 1C.Ine. drurti 2, the ring 14 appears ell iptical in projection although the inner periphery of the annular disc 3 is circular. In conventional machines of the type in question the annular disc 3 is inclined about the axis 15 which extends at right angles to the axis 10 which intersects the running-on point 7 and the axis of rotation 5 of the drum 2. In this way the respective narrowest gap occurs in the positions of 00 and 1800, considering the highest point 7 of the annular disc at which the tube R runs on to the drum 2 to be 00. The lowest point of the annular disc is at 1800, from after which the tube R is no longer slipped down.

However it can also be seen from Figure 3 that the respective largest gap is present in the region of 900 and 2700 commencing from the running-on point at 00.

In the case of larger tube diameters the slippage range is between 00 and 1800. whilst in the case of smaller tubes the slippage preferably takes place between 900 and 1800.

Figure 4 is an illustration of the invention. By offsetting the annular disc 3 relative to the drum 2 in an opposite direction to the drawing direction and where appropriate towards the running-on point, the narrowest gap between the annular disc and the drum now ranges between 900 and 1800. In the region of 27100 the gap is the largest bilt this gap is no longer of significance because the tube is no longer in contact with the annular disc at this point. Due to the reduced widths of this gap small tube diameters can no longer enter the space between the annular disc and the drum, whereby the aim of the invention is fulfilled.

As indicated in Figure 2 it is possible to adjust the position of the annular disc 3 relative to the drum 2 for which purpose the adjustment means 6 at the periphery of the annular disc bearing 4 are used. The adjustment can also take place by means of other devices, such as eccentric pressure components, wedges etc.

6

Claims

1. A device for drawing strand-like material, chiefly copper tubing, comprising a drawing drum which applies the necessary drawing force and is rotatable about a vertical axis of rotation, with a clamp which grips the end of the drawn material and is arranged on the outer surface of the drawing drum and with an annular disc which is arranged above the clamp, engages around the drum and is driven in the same direction and at the same speed as the drum and which is obliquely mounted in relation to the drawing plane of the drum for the purpose of dislocating the drawn turns, where the diameter of the annular disc about which the disc is pivoted into an oblique position extends at right angles to the diameter of the drum which itself extends through the meeting point of the tube with the drum and the axis of rotation thereof, characterised in that the axis of rotation (11) of the annular disc (3) is offset in relation to the axis of rotation (5) of,the drum (2) on the horizontal diameter (pivot axis 15) of the annular disc (3) in opposition to the incoming direction of the drawn material (R).

2. A device for drawing strand-like material as claimed in Claim 1, characterised in that the central axis (pivot axis 15) of the annular disc (3), about which the latter is pivoted into- an oblique position, is offset in relation to the axis of rotation (5) of the drum (2) in the direction of the meeting point (7) of the drawn material (R) with the drum (2).

3. A device for drawing strand-like material as claimed in Claims 1 and 21 characterised in that the displacement paths of the axis of rotation (11) of the annular disc (3) relative to the axis of rotation (5) of the drum (2) and of the central axis (15) of the annular disc (3) relative to the axis of rotation (5) of the drum (2) are adjustable.

4. A device for drawing strand-like material sustantially as herein described with reference to Figures 1, 2, or 4 of the accompnaying drawings.

Published 1990atThe PatentOffice. State House.8671 High Holborn. 1Andon WC1R 4TP. PurLher copies maybe obtained from ThePatentoffice 1, r Kwn tgd bv MultiDlex techWoues lt& St Mary Cray, Kent. Con. 1187