GB2346104A - Rigidised material - Google Patents

Abstract

A method of producing an elongate profile in which plain strip is initially corrugated to provide therein a plurality of longitudinal corrugations, but the corrugations are omitted in those regions of the width of the strip at which, subsequently, longitudinal bends are produced to convert the corrugated strip into a selected profile. The invention further resides in apparatus for use in the manufacture of elongate profile including a first roll pair for roll forming plain strip to produce therein a plurality of parallel longitudinally extending corrugations, said rolls of said pair having coacting circumferential grooves and ribs to form said corrugations and at least one of said rolls having at least one region with at least one rib omitted, whereby a band of said strip corresponding to said region is left free of corrugation, and, at least one subsequent roll station arranged to bend the corrugated strip along its length to form an elongate profile, the position, across the width of the strip, of said band being selected to coincide with a longitudinal bend produced by said at least one subsequent roll station.

Description

RIGIDISED MATERIAL This invention relates to a method of producing an elongate profile from the metal strip.

We have previously proposed methods of manufacturing rigidised metal strip, apparatus for manufacturing such strip, metal strip manufactured in accordance with the method, and elongate profile produced from the strip.

In these proposas the strip produced by the method is suitable for subsequent col roll forming into an elongate profile and the method inclues the steps of stretch forming plain metal strip to produce therein a plurality of longitudinally extending corrugations. There is a subsequent step of deforming the crests of the corrugations at one face of the strip, at spaced points along the length of the corrugations, to provided therein indentations. The strip is then subsequently cold roll formed to produce longitudinally extending bends in the strip which convert the strip from a generally planar configuration into a formed profile, for example a channel section or a box section.

It is found that where strip material is formed with longitudinally extending corrugations, then there can be difficulties in subsequent longitudinal bending of the corrugated strip to produce the desired profile, if the longitudinal bend necessary to produce the profile conflits with a longitudinal corrugation in the strip.

In accordance with the present invention therefore there is provided a method of producing an elongate profile in which plain strip is initially corrugated to provide therein a plurality of longitudinal corrugations, but the corrugations are omitted in those regions of the width of the strip at which, subsequently, longitudinal bends will be produced to convert the corrugated strip into a selected profile.

The invention further resides in apparatus for use in the manufacture of elongate profile including a first roll pair for roll forming plain strip to produce therein a plurality of parallel longitudinally extending corrugations, said rolls of said pair having coacting circumferential grooves and ribs to form said corrugations and at least one of said rolls having at least one region with at least one rib omitted, whereby a band of said strip corresponding to said region is left free of corrugation, and, at least one subsequent roll station arranged to bend the corrugated strip along its length to form an elongate profile, the position, across the width of the strip, of said band being selected to coincide with a longitudinal bend produced by said at least one subsequent roll station.

Desirably both of said rolls have at least one region with at least one rib omitted, said regions being arranged so as to produce a single band free of corrugation.

Preferably the or each region of the or each roll is a plain cylindrical region.

Preferably the diameter of the or each plain cylindrical region is such that the band free of corrugation is not displaced relative to the median plane of the strip.

In accordance with one example of the present invention elongate galvanised mild steel strip is passed through the nip of a pair of rolls which stretch the material in its width to produce therein a plurality of parallel, longitudinally extending corrugations. The stretch forming operation ensures that the overall width of the corrugated strip is substantially equal to the overall width of the plain strip prior to corrugation.

Selected elongate, longitudinally extending bands of the strip are left free of corrugations, the bands being selected in accordance with the profile which is to be produced from the strip such that the bands free of corrugations are the regions at which longitudinal bends are subsequently produced in the strip by the cold roll forming operation which converts the strip into a particular profile.

The rolls which perform the corrugating operation have a plurality of circumferentially extending ribs spaced apart by circumferentially extending grooves the ribs being equally spaced along the axis of the rolls.

The forms on the two rol Is are substantially identical except that the rol Is co-act with one another such that a rib on one roll overlies a groove of the other roll. However, in those regions where it is desired to leave the strip free of longitudinally extending corrugations then a rib or ribs of at least one of the two rolls are omitted so that no corrugations are stretched into the material in the corresponding band or bands of the strip material.

Naturally, if desired, both rolls can be free of ribs and grooves at the point where un-corrugated bands are required. In such an arrangement the rolls would have plain cylindrical regions so dimensioned that the strip material is not distorted relative to its median plane in those regions. However, it is to be understood that the provision of such plain cylindrical sections is not essential, and a similar effect can be achieved by simply omitting the rib or ribs on one of the two rolls, in the appropriate region of the roll, so that the strip is left with a longitudinal band or bands, which do not have corrugations formed therein, but the median plane of which need not be the median plane of the strip entering the corrugating rolls.

Desirably where a subsequent operation in the formation of the strip involves passage of the strip through the nip of a pair of rolls the upper one of which has axially extending ribs which serve to indent the upper surface of the corrugated strip to provide cross-grooves regularly spaced along the length of the upwardly extending corrugations, then the roll of the first pair from which the ribs are omitted is the lower roll so that the bands of the corrugated strip which are free of corrugations are not subjected to the cross grooving operation in the second roll pair.

Where the lower roll of the second pair of rolls has a plurality of shallow circumferential grooves to correspond with corrugations then it will be recognised that a wide shallow groove or grooves will be needed to accommodate each region where there is a band of uncorrugated material, although this will not be necessary if the band of uncorrugated material is left by the action of plain cylindrical regions on both rolls of the first roll pair.

The accompanying drawing is a composite drawing and illustrates, in axial cross-section, a first roll pair 11,12 in which, at the left hand side of the drawing, ribs of only the lower roll 12 are omitted, whereas at the right hand side of the drawing ribs and grooves of both rolls 11,12 are omitted, being replace by plain cylindrical regions 14 of a diameter such that strip 13 in the nip of the rolls is not displaced thereby.

It will be recognised that the concept of leaving bands of strip uncorrugated to facilitate subsequent forming into a profile can be applied to strip corrugated in other ways, for example corrugated by a press forming operation.

Claims (9)

1. CLAIMS : 1. A method of producing an elongate profile in which plain strip is initially corrugated to provide therein a plurality of longitudinal corrugations, but the corrugations are omitted in those regions of the width of the strip at which, subsequently, longitudinal bends are produced to convert the corrugated strip into a selected profile.
2. 2. Apparatus for use in the manufacture of elongate profile including a first roll pair for roll forming plain strip to produce therein a plurality of parallel longitudinally extending corrugations, said rolls of said pair having coacting circumferential grooves and ribs to form said corrugations and at least one of said rolls having at least one region with at least one rib omitted, whereby a band of said strip corresponding to said region is left free of corrugation, and, at least one subsequent roll station arranged to bend the corrugated strip along its length to form an elongate profile, the position, across the width of the strip, of said band being selected to coincide with a longitudinal bend produced by said at least one subsequent roll station.
3. 3. Apparatus as claimed in claim 2 wherein both of said rolls have at least one region with at least one rib omitted, said regions being arranged so as to produce a single band free of corrugation.
4. 4. Apparatus as claimed in claim 2 or claim 3 wherein the or each region of the or each roll is a plain cylindrical region.
5. 5. Apparatus as claimed in claim 4 wherein the diameter of the or each plain cylindrical region is such that the band free of corrugation is not displaced relative to the median plane of the strip.
6. 6. Apparatus for producing an elongate profile substantially as hereinbefore described with reference to the accompanying drawing.
7. 7. A method of producing an elongate profile substantially as hereinbefore described with reference to the accompanying drawing.
8. 8. Elongate profile produced by the method of claim 1 or claim 7.
9. 9. Elongate profile produced by the apparatus of any one of claims 2 to 6.