GB2126509A

GB2126509A - Drum drawing machine

Info

Publication number: GB2126509A
Application number: GB08323747A
Authority: GB
Inventors: Karl-Heinz Kemmerling
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1982-09-03
Filing date: 1983-09-05
Publication date: 1984-03-28
Also published as: GB2126509B; DE3233237C1; GB8323747D0; JPS5956914A

Abstract

A drum drawing machine has a mechanism for regulating the speed of rotation of a delivery basket 1 from which an elongate workpiece, eg. pipe, is fed to a drawing die 3. The mechanism comprises a pair of guides 6 which engage the leading turn of a coil of workpiece on the delivery basket 1 to define an arc R therebetween. A measuring device 7 locates the position of the workpiece in the arc relative to the axis of the delivery basket 1 and is coupled to a drive for the basket 1 to regulate the rotation thereof and thus the feed of the workpiece to the drawing die. A receiving basket 5 is arranged beneath a drawing drum 4 for receiving the drawn pipe. <IMAGE>

Description

SPECIFICATION A drum drawing machine The invention relates to drum drawing machines, and has particular application in continuous such machines, sometimes known as conti-drum drawing machines. Such machines are used in drawing wire and other elongate workpieces. The machine described herein is especially suited to the drawing of pipes.

In a conti-drum pipe drawing machine, a pipe borne in coil form on a delivery basket is carried through a drawing die, and then wound onto a drum which produces the requisite traction before being subsequently continuously deposited into a receiving basket rotating beneath the drum. The delivery and receiving baskets are driven, like the drum, by a direct current motor in each case, the rotational speeds of which must be coordinated.

The rotational speed of the delivery basket is particularly difficult to regulate, because the individual turns of the coil can have different diameters. The turns of the coils can also lie eccentrically in the delivery basket. This occurs particularly if the machine is charged with coils from outside sources for the first draw, or if the drawing sequence begins with large dimensions, so that owing to their great stability, the pipes do not assume a central position in the vicinity of the outer diameter of the delivery basket. These phenomena make the regulation of the speed of the delivery basket considerably more difficult.

It is known to equip conti-drum drawing machines with a regulating device for the delivery basket, which operates in the manner of a compensating roller. During the drawing process, the pipe presses in front of an arm, which acts upon a rotation potentiometer.

Through spring tension, the arm constantly rests against the pipe. This arrangement creates problems, in particular if very small dimensions are to be accommodated. In addition, with eccentric positioning of the coil, the total eccentric motion is transferred onto the control arm, which in turn releases a control pulse via the rotation potentiometer and thereby can incorrectly raise or lower the rotational speed of the delivery basket.

Control of the rotational speed of the delivery basket can also be carried out manually by an operator, who has therefore to remain constantly at the control desk. The preparation of the pipe for the next traction must be undertaken by a second operator, thus, this mode of operation is likewise considered disadvantageous.

The present invention contemplates a regulating device for the speed of the delivery basket, which only need respond when a turn of the pipe coil in the delivery basket lies at a greater or smaller diameter than the preceding one. In this way, the supply of pipe material to the drawing drum can be maintained accoring to a desired drawing speed. Such a device can also be usable for small pipe diameters.

According to the invention the leading turn of the coil, which is to be fed to the drawing die, is guided at two places, spaced apart from each other and preferably lying diametrically opposed to each other, with the section of pipe situated between the guides in the range of a measuring device for the position of the section of pipe. The measuring device is coupled to the drive for the delivery basket, normally through a calculating unit which converts the measured value of the measuring device into a control impulse for the drive.

According to the above, a drum drawing machine according to the invention comprises a delivery basket for carrying an elongate workpiece in coil form; a drum for rotating the delivery basket to feed such workpiece to a drawing die; and a regulating mechanism coupled to the drive for controlling the rotational speed of the delivery basket, which mechanism comprises a pair of guides for engaging a said workpiece at two spaced positions on an arc thereof on the delivery basket whence such workpiece is fed as aforesaid; and a measuring device for locating the position of a said workpiece between the guides relative to the axis of the delivery basket, the measuring device being coupled to the drive for regulating the rotational speed of the delivery basket in accordance with said relative position.

By adopting the present invention, regulation of the speed of the delivery basket can be fully automated, without the disadvantageous installation of compensating rollers affecting materials with small dimensions. In the proposed device it is of no account whether the coil lies centrally or eccentrically in the delivery basket.

The measuring device is preferably a noncontact device, typically a light barrier arrangement operating on the basis of proximity indicators. This enables in a simple manner, a non-contact detection of the position of the pipe within the light barriers. The measuring device conveniently has a forked shape, and/ or can be pivoted out of, and back into, the region of the delivery basket, which facilitates the filling or charging of the delivery basket.

While the light barrier technique is preferred, the measuring device may alternatively be provided with electric and/or pneumatic switches to measure the position of the pipe.

The invention will now be described by way of example and with reference to the accompanying schematic drawing in which: Figure 1 is a diagrammatic representation of a conti-drum drawing machine; and Figure 2 shows a measuring device according to the invention.

The machine shown in Fig. 1 has a delivery basket from which a pipe 2, is fed to a drawing die support 3 and then to a drawing drum 4. Beneath the drawing drum 4, a receiving basket 5 is arranged, which receives the finished drawn pipe.

On commencement of the drawing process, the leading turn on the pipe coil is raised by the operator out of the delivery basket and is placed into the guide arrangement 6. As shown in the drawing each guide has a set of guide rollers and the guides are disposed diametrically opposite to each other. Each guide has four rollers which hold the coil in position. After threading the start of the pipe into the drawing die of the drawing die support 3 in the known manner, the measuring device 7 according to the invention is pivoted inward such that the section of pipe R lying between the sets of guide rollers 6 comes to lie in the range of the light barrier arrangement. This arrangement is constructed as light strip device 8, as represented diagrammatically in Fig. 2 on an enlarged scale. The light strip device 8 has a plurality of light barriers lying opposite each other, which are interrupted according to the position of the pipe 2 within the fork-shaped light barrier arrangement. The interruption of the light barrier is converted in a calculating unit (not shown) into a regulating impulse for the drive of the delivery basket 1, so that the delivery of the pipe 2 from the coil can take place largely free from traction.

Claims

1. A drum drawing machine comprising a delivery basket for carrying an elongate workpiece in coil form; a drive for rotating the delivery basket to feed such workpiece to a drawing die; and a regulating mechanism coupled to the drive for controlling the rotational speed of the delivery basket, which mechanism comprises a pair of guides for engaging a said workpiece at two spaced positions on an arc thereof on the delivery basket whence such workpiece is fed as aforesaid; and a measuring device for locating the position of a said workpiece between the guides relative to the axis of the delivery basket, the measuring device being coupled to the drive for regulating the rotational speed of the delivery basket in accordance with said relative position.

2. A machine according to Claiml wherein the guides are located diametrically opposite on either side of the delivery basket, whereby said arc is semi-circular.

3. A machine according to Claim 1 or Claim 2 wherein each guide comprises a set of rollers for engaging a said workpiece.

4. A machine according to any preceding Claim wherein the measuring device is coupled to the drive through a calculating unit for converting signals from the measuring device into regulating impulses for the drive.

5. A machine according to any preceding Claim wherein the measuring device is a noncontact device.

6. A machine according to Claim 5 wherein the measuring device comprises a light barrier arrangement operable on the basis of proximity indicators.

7. A machine according to any preceding Claim wherein the measuring device is forkshaped and mounted for pivotal movement over a said workpiece between the guides.

8. A machine according to any of Claims 1 to 5 wherein the measuring device has at least one of electric and pneumatic switches for locating a said workpiece between the guides.

9. A drum drawing machine substantially as described herein with reference to the accompanying drawing.