This invention relates to a rolling device for trimming the edge or edges of a cut or slit steel strip. It relates also to the use of such a rolling device.

Instead of rolling beams in a profile rolling mill, it is possible to slit a hot rolled wide band into strips that are coiled and to bend in a roll-forming machine such a strip into a beam for example into a U-beam for making up a frame for a truck or the like. The strip is usually straightened in a tension leveller before being introduced in the roll-forming machine. The strips will get sharp corners with burrs when slit. The sharp corners may cause injuries when handled and will not be properly covered when painted, particularly when painted with powder paint.

The present invention concerns a rolling device for trimming the edge of a metal strip. It comprises a pair of rollers arranged at an angle to each other for rolling the two cor¬ ners of an edge of the strip. Such a machine is known from GB 2145958 A.

There will be a considerable wear on the rollers and the invention seeks to provide a device of this kind which need to be regrinded only at long intervals and that will use the material efficiently, that is, more material can be used for the rolling and less mate¬ rial has to be ground off.

In accordance with the invention, this object is accomplished in a rolling device of this kind in that the rollers have hard metal rings that have working surfaces directed at an angle to each other and surfaces that are at an angle to the respective working surface and are adjacent each other with a slot in between them.

The invention will be described with reference to the accompanying drawings which, by way of example, show an embodiment of the invention.

CONFIRMATION COW

Fig 1 is a horizontal view of a rolling device. Fig 2 is a top plan view of the device shown in Fig 1. Fig 3 is an end view seen as indicated by the arrows 3-3 in Fig 1. Fig 4 is a sectional view at a larger scale of a pair of rollers shown in Fig 1.

The rolling equipment shown in the figures comprises a frame with four guides 10 - 13. Two carriers 14, 15 are movable along the guides and they are mechanically intercon¬ nected by means of a linkage 16, 17, 18. The link 17 is pivotably mounted on a journal 19 in the frame and the linkage will force the two carriers 14, 15 always to be sym¬ metrically located on each side of the journal 19.

Two hydraulic cylinders 21, 22 are coupled between the frame 9 and the respective carrier 14, 15 for moving the carriers along the guides. Each carrier has two free-rolling rollers 24, 25; 26, 27 and the rollers are arranged to trim one corner each of the edges of a steel strip 28 between the roller pairs. The steel strip 28 is shown in Fig 1 and Fig 4 only. During the rolling operation, the carriers are forced together by means of the hydraulic cylinders and the symmetry makes a force balance. Eight deflection restrainers 31 - 34, 45, 46 (seven of which can be seen on the figures only) are mounted on the guides to keep the strip 28 almost plane. They have a slight gap to the strip in order to reduce the friction and they are circular so that they can be turned and locked in a new position when they have been worn down in one position. They can be mounted off-set or have a slightly varying radius so that they can be adapted to various strip thicknes¬ ses.

In Fig 4, a part of the carrier 14 is shown in a view as in Fig 1, but its working rollers 24, 25 are shown in section. The rollers 24, 25 are mounted on roller bearings 35, 36 and 37, 38 on journals 39, 40 that are fixed to the carriers 14, 15. The inner rings 35, 37 of the bearings are fixed to the journals by means of nuts 41, 42 and roller units 55,

56, 57 and 58, 59, 60 are clamped against shoulders 53, 54 by means of nuts 51, 52. Each roller unit comprises two rings 55, 56 and 58, 59 respectively that clamp a ring

57, 60 between them. The rings 57, 60 are made of so called hard metal, for example tungsten carbide in a metal matrix.

The roller and their hard metal rings 57, 60 have working surfaces 61 , 62 that are per¬ pendicular to the bisectors of the corners of the strip 28. These surfaces 61, 62 meet surfaces 63, 64 that are parallell to each other in the section of Fig 4 and directed towards each other with a small gap in between them. The working surfaces 61, 62 are at right angles in the section shown and the angle between the surfaces 61 and 63 is dull, namely 135°, as is the angle between the surfaces 62 and 64.

When the working surfaces 61, 62 become worn, one screws off the nuts 51 , 52, remo¬ ves the roller units 55, 56, 57 and 58, 59, 60, grinds the working surfaces 61 , 62 and remounts the roller units. The working surfaces 61, 62 can be ground many times until most part of the hard metal rings 57, 60 have been ground off. For one and the same thickness of the steel strip 28, the corners of the steel strip 28 will all the time be on the lines 70, 71 irrespective of the number of regrinding. The lines 70, 71 are parallell with the surfaces 63, 64.

There will be burr when trimming a corner with a flat working surface of a working roll. The burr disappears usually when the strip is blasted before being painted. How¬ ever, it may be advantageous to roll the corners of the steel strip with grooves in the working surfaces 61, 62 and such a groove may be semi-circular and have a radius of 0,2 - 2 mm. For one and the same thickness of the steel strip 28, the groove will always be on the line 70 or 71, that is, at the same distance from the corner between the sur¬ faces 61 and 63 or 62 and 64, which will simplify the grinding. In order to permit for an adaption of the distance between the grooves to the thickness of the steel strip 28, the carriers 14, 15 may include means for adjusting the axial positions of the journals 39, 40 so that the width of the gap 65 can be varied. These adjusting means could be power actuated and should be movable together so that there will always be a symmetry.

The rolling device described and illustrated can be mounted between a tension leveller and a roll-forming line. It will then be used as an inlet guiding device for the roll- forming line. Such an integral line will be suitable for roll-forming a steel strip to a beam, for example a U-beam that can be used for making up the frame of a truck or the like.