GB2118084A - Cold roll drive mechanism - Google Patents

Abstract

A rolling mill drive system comprises two distinct belts or chains 6, 7, driven by a common motor 3. As can be seen, each chain drives alternate upper and lower rolls, and each stand is driven by both chains. The arrangement facilitates tool and roll speed changes, and greatly reduces stresses in the mill frame. <IMAGE>

Description

SPECIFICATION Cold roll drive mechanism The present invention relates to cold roll forming machines and in particular to roll driving systems.

A comprehensive background to the invention is provided by two publications and the bibliographies contained in them: "Cold Forming", W. G. Kirkland, Iron and Steel Engineer, November 1959.

"A Survey of Sheet Metal Cold Roll Forming", M. A. Wallis, British Steel Corporation Corporate Laboratories Paper Number Mw/a 6/71.

There are three predominant roll drive systems: 1. Direct drive through gearboxes with fixed ratios between top and bottom rolls.

2. Drive through hydraulic gearboxes, either one per roll or one per roll pair.

3. Single chain drive.

The problem with the first two methods is one of a lack of flexibility. A fixed speed ratio between the rolls in a roll pair is limiting in terms of the size of section which the machine is capable of rolling and also can impose size limitations on the rolls.

The fixed speed ratio also means that a machine which is originally designed to cope with shallow sections could probably not be used with deep sections. Both methods 1. and 2. are also very costly in manufacturing terms.

A single chain does help to overcome the problems referred to in the previous paragraph in that by using a chain drive there is no need to design to a standard speed ratio between rolls on all roll pairs on a machine. However, the single chain does have three disadvantages: a) Because of the sprocket sizes, there is a limit to the minimum distances between the centres of the rolls before the chains touch.

b) The sprockets are not interchangeable so that the speed ratios are fixed once the machine design is finalised.

c) The routing of the chain around the sprockets imposes considerable stresses on the bedframe of the machine.

According to one aspect of the present invention there is provided a rolling mill drive system, suitable for use on a mill comprising at least one rolling stand, said drive system comprising at least two flexible driving members capable of carrying tensile loads and adapted to transmit torque from a powered rotating drive member to power absorbing rotating driven members, each driven member being associated with a mill roll, the drive member being adapted to drive the two flexible driving members, one flexible driving member driving the first driven member and the other flexible member driving the second driven member.

Equally, the drive is applicable to a mill comprising a plurality of stands. Thus, in accordance with a further aspect of the present invention, there is provided a rolling mill drive system, suitable for use on a mill comprising a plurality of rolling stands, said drive system comprising at least two flexible driving members capable of carrying tensile loads and adapted to transmit torque from a powered rotating drive member to power absorbing rotating driven niembers, each driven member being associated with a mill roll, the drive member being adapted to drive the two flexible driving members, one flexible driving member driving the alternate upper driven members of successive stands and the lower driven members of the next adjacent stands, the other flexible member driving alternate lower driven members of successive stands and the upper driven members of the next adjacent stands.

The flexible driving members may each comprise an endless chain, in which case the rotating driven and driving members are sprockets; the chain may be of the simplex or duplex type.

Alternatively, the flexible driving member comprises an endless toothed belt, and the rotating driven and driving members are toothed wheels. The toothed belt will need to be of the type having teeth on both belt faces, unless there is room to introduce a twist in the belt between adjacent engagements.

It may be desirable that the flexible driving members engage rotating idlers so arranged as to achieve satisfactory routes for said flexible driving rnembers and to ensure arcs of contact with the driven and driving members which are adequate to transmit torque without slipping or jumping.

Conveniently, the drive member comprises two sprockets on a common drive shaft, one driving each of the two chains.

Since chains and toothed belts have limited flexibility in one plane, it is desirable that the two flexible driving members each lie in one of two parallel planes, the planes being perpendicular to the axes of the rolls and spaced apart, in which case the driven members of a given roll stand will lie in different planes.

Embodiments of the present invention will now be described with reference to the accompanying drawings, in which: Fig. 1 shows a diagrammatic side elevation of a five stand cold rolling mill.

Fig. 2 shows an end view of part of the machine Fig. 3 shows an alternative arrangement to that in fig. 2.

Referring to figure 1, the machine frame 1 of a cold rolling mill includes five two-roll stands 2, for example of the type described in more detail in our co-pending application.

A motor (not shown) drives a pair of main driving sprockets 3. At each end of the frame 1 is a pair of idler sprockets 4.

Each roll 5 carries at one end thereof a roll drive sprocket 2 engaged by one or other of two drive chains 6, 7.

Referring briefly to figure 2, it will be noted that the upper and lower roll drive sprockets of a given roll stand are displaced axially. This is of course necessary in order to avoid the two drive chains engaging each other where their paths cross, and this displacement will of course correspond to the axial displacement between the sprockets forming the pairs already referred to as the drive pair 3 and the two idler pairs 4. Note also from figure 2 that this means that the roll centres in a stand can approach each other more closely than would be the case with gear drive or the use of a single drive chain.

Reverting to figure 1, it will be seen that the inner drive chain drives successively the lower roll of the first stand, the upper roll of the second stand and the lower roll of the third stand, and so on. The outer drive chain conversely drives the upper roll of the first stand, the lower roll of the second stand, and so on.

The drive sequence in the preceding paragraph could equally well be reversed of course, whilst still retaining the requirement that each of the chains drives successively the opposite roll of the next stand.

Although not illustrated, it may be desirable in certain circumstances to increase the engagement sectors between the chains and sprockets, particularly the main drive sprockets 3.

To this end, chain guides or idlers may be used as necessary.

Referring now to figure 2, roll support shafts 10 are carried in roll support blocks 11 which are in turn held in the machine frame 1, for example as described in our co-pending application. Note that, in figure 2 the rolls are to the left, and therefore it can be seen that the drive sprockets are carried inwardly of the roll support blocks.

Spacers 12 incorporate turned recesses in order to increase the range of sprocket sizes which can be used; also, this of course enables the rolls of a given stand to be placed closer together than would otherwise be possible.

Drive from the sprockets 2 to the rolls as such may be for example via keyways or splines, or any convenient method. However, when the present invention is used in conjunction with the inventions described in our co-pending applications, a preferred form of drive transmission is used, as will now be described.

In figure 2, shaft 10 does not rotate, and therefore bearings 13 are positioned as shown to allow for rotation of sprockets 2. The sprockets 2 and spacers 12 may be integral or separate pieces mounted on a common sleeve to form an integral unit.

Drive from the sprocket/spacer assembly is transmitted to rolls 5 by suitable means such as face to face shear pin, driving key, or the like.

A modification is shown in figure 3, from which it will be seen that the bearings 1 3 are mounted in support blocks 11 to support a rotating sleeve 14 upon which are mounted the sprockets 2 and spacers 12.

Reverting now to more general aspects of the present invention, although a five stand mill has been described, it will be appreciated that the invention is applicable to a mill of any number of stands, from one upwards.

Although chain and sprocket drive has been illustrated, it is clear that the invention can equally well make use of a toothed belt drive, or V-belt, provided that the torque required is within the scope of the drive system adopted. These and other modifications falling within the scope of the present invention will be apparent to those skilled in the art.

Claims (12)

Claims

1. A rolling mill drive system, suitable for use on a mill comprising at least one rolling stand, said drive system comprising at least two flexible driving members capable of carrying tensile loads and adapted to transmit torque from a powered rotating drive member to power absorbing rotating driven members, each driven member being associated with a mill roll, the drive member being adapted to drive the two flexible driving members, one flexible driving member driving the first driven member and the other flexible member driving the second driven member.

2. A rolling mill drive system, suitable for use on a mill comprising a plurality of rolling stands, said drive system comprising at least two flexible driving members capable of carrying tensile loads and adapted to transmit torque from a powered rotating drive member to power absorbing rotating driven members, each driven member being associated with a mill roll, the drive member being adapted to drive the two flexible driving members, one flexible driving member driving the alternate upper driven members of successive stands and the lower driven members of the next adjacent stands, the other flexible member driving alternate lower driven members of successive stands and the upper driven members of the next adjacent stands.

3. A rolling mill drive system in accordance with claims 1 or 2 in which the flexible driving member comprises an endless chain, and the rotating driven members and the rotating drive member are sprockets.

4. A rolling mill drive system in accordance with claims 1 or 2, in which the flexible driving member comprises an endless toothed belt, and the rotating driven members and the rotating drive member are toothed wheels.

5. A rolling mill drive system in accordance with any of the preceding claims, in which the flexible driving members engage rotating idlers so arranged as to achieve satisfactory routes for said flexible driving members and to ensure arcs of contact with the driven and driving members which are adequate to transmit torque without slipping or jumping.

6. A rolling mill drive system in accordance with claim 3, in which the drive member comprises two sprockets on a common drive shaft.

7. A rolling mill drive system in accordance with claims 1 or 2, in which the at least two flexible driving members each lie in one of at least two parallel planes, the planes being perpendicular to the axes of the rolls and spaced apart.

8. A rolling mill drive system in accordance with claim 7, in which the driven members of a given roll stand lie in different planes.

9. A rolling mill incorporating a drive system in accordance with any preceding claim.

10. A rolling mill driving system substantially as described in the accompanying specification.

11. A rolling mill substantially as described in the accompanying specification.

12. Any major component knowingly manufactured with the intention of it being used in conjunction with a rolling mill drive system in accordance with any preceding claim.