MONITORING OF PROFILED SHEETS

TECHNICAL FIELD

The present invention relates to apparatus and methods for monitoring characteristics of profiled sheet, and in particular to monitoring a width measure of the profiled sheet.

The invention has been developed especially for the monitoring of cover widths of profiled sheet and is herein described in that context. However, it is to be appreciated that the invention is not limited to that use as aspects of the invention are applicable to the monitoring of other characteristics of profiled sheet.

BACKGROUND ART

An important measure of profiled sheet is its "cover width". Cover width is usually taken in the art to be the width of the sheet between the crests of the two outermost profiles of the sheet. Cover width, as opposed to actual width, is important because, when laying sheet to cover a surface or structure, the lateral edge of one sheet will overlap the lateral edge of an adjacent sheet. The amount of sheet required to cover a surface or structure is therefore the cover width.

A known issue for the formation of profiled sheet is the accurate control of cover width during formation. Cover width outside manufacturers' tolerances, for example 2-3mm for uniform corrugated metal roll-formed sheet, can have an unacceptable cumulative effect across a wide roof or wall span. Aside from the lateral dimensional consequences, deviations of cover width can imply deviations in corrugation height and can have a significant effect on the load bearing characteristics of a sheet, e.g. the ability of the sheet to withstand people walking on it across a roof without buckling or damage. Such deviations can also affect overlap of longitudinal edges of the sheet, leaving unacceptable gaps between the sheets. With profiled sheets that have been pre-marked or pre-cut bulk to their final shape for a complex roof, for example, the issue is particularly significant.

Current industry practice is to take production samples from stacks to check the cover width. This practice increases safety risk and involves both a degree of waste and a risk of scratching the sheet.

SUMMARY OF THE INVENTION

According to a first aspect, there is provided a device for use in monitoring a width measure for a profiled sheet having longitudinally extending formations, the device incorporating a tracking device operative to monitor a first one of the longitudinal formations so as to establish information indicative of the distance of the first formation relative to a second one of the formations so as to allow for monitoring of the width measure. hi a particular form, the tracking device is operative to monitor the first formation as it moves past the tracking device generally in the longitudinal extending direction, hi accordance with this form, the monitoring device can be used to test whether products, such as profiled roll formed products, are formed within acceptable tolerances. These tests can be performed during roll forming. This means that production does not need to be stopped or reduced to test the width measure such as the cover width and as such overall production of profiled sheet can be increased relative to prior art methods. Also at least some embodiments of the device measure width without contacting the sheet, thus reducing the risk of scratching or otherwise damaging the sheet.

The tracking device used in the monitoring device may take various forms. In one embodiment the tracking device is a transceiver device and more preferably a light transceiver device such as a laser transceiver.

In a particular embodiment, the transceiver device includes a pair of spaced transceivers that are operative to track the first formation using the difference between the respective distances established between each transceiver of the transceiver pair and the first formation. In a particular form the transceivers of the device are located on either side of a desired position of a crest of the first formation.

In an alternative form, the tracking device is in the form of a contact member mounted to a support structure that is configured to engage the first formation, the contact member being mounted to the support structure for lateral movement as it tracks the first formation, hi a particular form the contact member is a rotatable wheel shaped to engage the first formation at a laterally consistent position relative to the formation by conforming at its rim to the cross-sectional shape of the formation.

In one embodiment, the device the first formation is tracked to obtain information of the position of the first formation relative to desired position, hi accordance with that arrangement, the tracking device may be arranged to establish the lateral displacement of the first formation from this desired position. By monitoring this lateral displacement, useful information can be established to monitor the width measure.

In accordance with a second aspect, there is provided a device for use in monitoring a profiled sheet having longitudinally extending formations, the device incorporating a tracking device operative to monitor a first one of the longitudinal formations so as to establish information indicative of the distance of the first formation relative to a reference.

In one form, the reference relates to a desired position of the first formation. In a particular form, the tracking device is arranged to establish the distance in a lateral direction of the first formation from the desired position.

In another form, the reference is a second one of the formations.

In a particular embodiment of a device according to any form described above, a second tracking device is provided that is operative to monitor a second formation. The monitoring of the second formation then provides a reference for monitoring the width measure.

In one form the information indicative of the distance between the first and second formations is provided at least in part from the first and second tracking devices. hi one form, the first and second formations are the outermost profiles on the profiled sheet and in a particular form the distance between the first and second formations is a cover width of a profiled sheet.

In one form, at least one of the tracking devices is able to move laterally on tracking of its formation, and wherein the distance between the tracking devices is indicative of the distance between the first and second formations, and the device further includes means to measure the distance between the tracking devices. In a particular form, a time of flight instrument is used to measure the spacing of the tracking devices. Typically this time of flight device comprises a laser beam generator fixed with respect to one tracking device and a reflector for the laser beam fixed with respect to the other tracking device. hi an alternative arrangement, each tracking device is arranged to establish a lateral displacement of its formation from a desired position and wherein the lateral displacements are indicative of the distance between the first and second formations, hi one form, the desired position of the first formation is at a constant predetermined distance from the desired position of the second formation, hi a particular form, this predetermined distance is the desired width measure of the profiled sheet. The second tracking device may take various forms. In one form the tracking device may merely provide a reference for the first tracking device with the position of the second formation being held constant. Alternatively, the position of the second formation may also vary and therefore the second tracking device is arranged to monitor the second formation so as to be able to provide information on the variation of its position. hi one form, the second tracking device is in the form of a transceiver as described in any form above.

In an alternative form, the second tracking device is in the form of a contact member mounted to a support structure and configured to engage the second formation at a laterally consistent position. This second contact member may be of a similar construction to the first contact member and designed for lateral movement as it tracks the second formation.

The device, in any form described above, may be provided with a feedback loop in which upstream or downstream equipment either adjusts the width measure of the sheet or compensates for detected variations therein.

In a particular form, the profiled sheet comprises a repeated pattern of formations that extend across the sheet and may be in the form of corrugations or in the form of ribs interconnected by pans or any combination thereof.

In a particular form, the profiled sheet is a roll formed metal product. In yet a further aspect, there is provided an apparatus for obtaining a width measure for a roll-formed metal product during or after roll-forming, including: support structure; a pair of spaced contact members mounted to and projecting from the support structure for rotatably engaging respective longitudinally extending formations of the roll-formed metal product as it moves past the support structure generally in the longitudinally extending direction, wherein each of the contact members is configured to engage the respective formation at a laterally consistent position relative to the formation and wherein at least one of the contact members is mounted to the support structure for lateral movement as it tracks its respective formation; and means to measure the spacing of the contact members laterally of said direction, from which may be derived a width measure for the roll-formed metal product.

In yet a further aspect, there is provided a method of monitoring a width measure of a profiled sheet having longitudinally extending formations, the method comprising the steps of: tracking first and second ones of the formations; establishing information indicative of the distance of the first formation relative to the second formation; and using the information to monitor the width measure.

In one form, the method further comprises the steps of providing first and second tracking devices to track the first and second formations, and measuring the distance between the first and second tracking devices to form at least part of the information indicative of the distance of the first formation relative to the second formation. hi an alternative arrangement, the first formation is tracked to obtain information on the position of the first formation relative to a desired position. In one form, the second formation is tracked to obtain information on the position of the

second formation relative to a desired position of that second formation. In a particular arrangement, the method further comprises the step of establishing the lateral displacement of the first formation from its desired position, and establishing the lateral displacement of the second formation from its desired position and then using the lateral displacement of the first and second formations to form at least part of the information indicative of the distance of the first formation relative to the second formation. hi yet a further aspect, there is provided a device for use in monitoring a longitudinally extending formation of a profiled sheet, comprising first and second spaced transceivers each arranged to establish the distance of that transceiver from the formation and operative to determine a characteristic of the formation as a function of the respective distance. hi yet a further aspect, there is provided a method of monitoring a profiled sheet having longitudinally extending formations, the method comprising the steps of: tracking a first one of the formations; establishing information indicative of the distance of the first formation relative to a reference; and using the distance to monitor a characteristic of the sheet. hi one form, the characteristic is a width measure of the sheet, hi one form, the reference relates to a desired position of the sheet and the information is indicative of a lateral displacement of the formation from this desired position, hi another form, the reference is a second one of the formations.

Accordingly, monitoring devices and methods of monitoring are disclosed that allow the cover width to be monitored by determining the lateral distance between the outermost two formations of the profiled sheeting. These devices and methods may monitor the distance directly (such as by monitoring the distance between the first or second tracking devices) or by monitoring the position of one or both formations relative to a reference position (such as by monitoring the lateral displacement of a formation from a desired position), hi either case the distance between the two outermost formations is still able to be monitored, hi addition, the absolute position of each formation in space does not need to be calculated; only the distance between the two formations is required.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Fig. 1 is a side elevation of an apparatus for measuring cover width of profiled sheet in accordance with a first embodiment of the present invention;

Fig. 2 is a detailed side elevation of the apparatus illustrated in Fig. 1; Fig. 3 is a side elevational view of a device according to another embodiment of the invention; and

Fig. 4 is an end elevation of the device illustrated in Fig. 3.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Figs. 1 and 2, illustrates a device 15 for monitoring and/or measuring a width measure for a profiled sheet having longitudinally extending formations, or profiles. The profiled sheet of the following described embodiment is in the form of corrugated metal sheet 10, however as will be understood, the embodiment may be adapted for use with any profiled sheet, hi this embodiment, the cover width of the corrugated sheet 10 is determined by determining the distance between the two outermost profiles 12, 14. The device 15 is configured to be used in conjunction with a roll-forming apparatus so that it can determine cover width during roll-forming, for example immediately downstream of a final roll stand or immediately downstream of other equipment such as a pre-marker station. It is preferably positioned over the path of the corrugated metal sheet 10. Alternatively, the device could also be adapted for offline cover width determination.

The device 15 includes a support in the form of a rigid structural beam 16 which is configured to extend laterally across the corrugated sheet 10 and two tracking devices in the form of transceiver devices that are mounted to the beam 16. The transceiver devices may be in the form of sonic, optical, radio frequency, etc, devices, but in this embodiment are in the form of laser devices. A first of the transceiver devices is in the form of a first pair 17 of laser devices 18, 20, and a second of the

transceiver devices is in the form of a second pair 21 of laser devices 22, 24. In this embodiment, the laser devices of each laser device pair 17, 21 lie on a plane substantially parallel with a notional plane on which the corrugated sheet 10 lies. The first 17 and second 21 pairs of laser devices are spaced apart a predetermined distance. The predetermined distance relates to the desired cover width of the sheet being measured, m this embodiment, the desired cover width is 762mm, but may be more or less depending on the profiled sheet being tested. Referring to Fig. 2, the laser devices 22, 24 of the second pair 21 are configured to be positioned in relation to an expected, or theoretically desired position 28 (illustrated in Fig. 2 in dotted outline) of their respective related profile 14. The laser devices 18, 20 of the first pair 17 are similarly positioned in relation to their related profile 12. hi this way, the laser devices 22, 24 are respectively positioned on opposite sides of a crest 30 of the theoretically positioned profile 28 and equispaced from the crest 30. The lasers 18-24 are configured to measure the distance between themselves and the corrugated sheet 10 as a function of the time taken to send and receive a laser signal 32 to the corrugated sheet. The lasers 18, 20, 22, 24 are configured such that their signals are orthogonal to the notional plane of the corrugated sheet 10.

The distance difference between the lasers of each laser pair is an indication of whether there is a displacement in the position of the formation to its desired position. This in turn can be used to monitor the cover width of the corrugated sheet 10. Each laser pair is positioned with respect to its relative profile such that there is a zero displacement from a desired cover width of the corrugated sheet 10 when

O = D1 -D2 and

0 - D3 - D4, where Dl is the distance between laser 18 and the corrugated sheet,

D2 is the distance between laser 20 and profile the corrugated sheet,

D3 is the distance between laser 22 and the corrugated sheet, and

D4 is the distance between laser 24 and the corrugated sheet.

Given that the corrugations of the sheet 10 are regular and their desired amplitude and pitch are known, it is possible to determine the actual cover width of

the corrugated sheet 10 being tested. This may be represented by the following equation:

Actual cover width = desired cover width + ((D2 - Dl) + (D3 - D4))/c (Eq. 1) where c is a derived constant which will be different depending on the amplitude, shape and pitch of the profiled sheet being measured.

For example, typical corrugated sheet, such as the corrugated sheet 10 illustrated in the Figures, ideally tends to have a lateral cross-section of a regular sinusoidal wave. Using as an example corrugated sheet typically used in Australia for roofing, a lmm increase in cover width leads to the following result: (D2 - Dl) + (D3 - D4) = approximately 1.46 mm

Therefore, for Equation 1 above when determining the actual cover width of typical Australian roofing corrugated sheet, c = 1.46. As will be appreciated, c can be calculated for different types of profiled sheet in alternative embodiments, including for profiled sheet having regular profiling which is not sinusoidal, but step-like, having angled sloped faces between steps.

It is preferred that the lasers of each laser pair, such as lasers 18 and 20 or lasers 22 and 24 of the illustrated embodiment, are projected at the slope of the theoretical profile 28 on either side of the theoretical crest 30.

In use, a just roll-formed corrugated metal sheet passes rapidly below the lasers 18, 20, 22, 24, travelling in a longitudinal direction with respect to its corrugations. Each laser pair 17, 21, in conjunction with a controller, is aligned with a respective on of the two outermost profiles 12, 14. This desired position will be different depending on the type of profiled sheet being measured. The positions of the two profiles 12, 14 are determined as described above and the cover width, or variation thereof, determined.

In this embodiment, variation of cover width beyond pre-determined tolerances may trigger an alarm at a display station or be part of a feedback loop with the corrugated sheet manufacturing apparatus to adjust its settings to correct the cover width, or an upstream pre-marker station may compensate for the detected undesired variation.

Thus, the above described embodiment has the advantage of having no moving parts and no contact with the corrugated sheet 10. The set up, such as determining "c" is also relatively simple in its calculation.

The preferred embodiments have been described with respect to the use of laser pairs. In an alternative embodiment, single lasers are used to determine deviation from a desired cover width, hi this embodiment, a first single laser is projected at the first outermost profile 12 and a second single laser is projected at the second outermost profile 14. In this embodiment, each laser is positioned in relation to the theoretical crest 30 of its respective outermost profile. The distance of each single laser is predetermined, such that if the actual position of the related profile is laterally shifted, the measure of lateral shift can be determined as a function of the predetermined distance, the actual measured distance between laser and profile, and the shape of the profile. This deviation can then be used to determine the cover width, given that the distance between each laser can be measured or predetermined. As will be understood, this embodiment is more complicated in determining the actual cover width compared with the first described embodiment, meaning the first described embodiment has advantages of simplicity over this alternative embodiment. For example, the differencing of measurements made by the lasers of each pair negates the need to know or have a predetermined or determined theoretical distance between the lasers and the theoretically positioned profile. Nevertheless, this alternative embodiment may still be useful in determining cover width.

Referring to Figs 3 and 4, an alternative embodiment of a device 100 includes a support structure generally indicated at 200 and, mounted atop and projecting from the support structure, a pair of spaced contact members in the form of solid moulded wheels 300, 320. The apparatus is provided in situ in a roll-forming line, for example immediately downstream of the final roll stand or immediately downstream of other equipment such a pre-marker station. It is positioned immediately under the path of the roll-formed metal product, in this case corrugated steel sheet indicated at 10.

The main component of support structure 200 is a rigid steel beam 220, of box or other suitable cross section, that extends laterally of the steel sheet path and has respective projecting end tabs 240 by which the beam 220 is fixed to a pair of

upstanding threaded studs, 260, 270. Studs 260, 270 are in turn rigidly fastened to respective uprights 650 of the machine frame by angle brackets 280, employing bolts and vertical slots 290 to permit vertical adjustment.

A helical compression spring 250 is provided on each of studs 260, 270 between bracket 280 and beam tab 240. These springs bring the wheels 300, 320 into firm contact with the corrugated steel sheet 10 passing overhead up to a limit set by nuts 420 on studs 260, 270.

Tracking devices in the form of wheels 300, 320 are concavely shaped at their rim to conform closely to the transverse cross section of the recess formations in the steel sheet 10 defined by the undersides of the crests of respective outermost profiles 12, 14. This conformity may be built into the original moulded shape or may arise through wear of the wheels by the passing sheet.

Each wheel 300, 320 is rotatably mounted on axle 340 in upstanding pair of brackets 350 on a respective saddle 360, 370 that is slideable longitudinally of beam 220 and laterally of the longitudinally travel direction of sheet 10 on a respective linear bearing 380, 390. The limits of travel are defined by studs 440 on a side of beam 220.

Saddles 360, 370 have overhanging side plates 500, 510 that cooperatively carry a time-of-light measuring instrument 600 consisting of a laser generator 520 on side plate 510 and a complementary reflector 540 on the remote end 550a of a square section beam 550. Beam 550 projects cantilever-fashion from side plate 550 parallel to beam 220 to its remote end 550a near, but not too near, the laser beam output window of laser beam generator 520.

During operation of the illustrated apparatus, a just roll- formed corrugated steel sheet 10 passes rapidly overhead, travelling in the longitudinal direction of its corrugations. Wheels 300, 320 rotatably engage the respective recess formations defined by crests adjacent the side edges of the sheet. The time-of-flight instrument 600, in conjunction with an associated controller, accurately determines the centre-to- centre spacing of wheels 300, 320 and therefore of the crests of profiles 12, 14, which is the cover width of the sheet. Because saddles 360, 370 are laterally moveable along

beam 220, wheels 300, 320 can move as they track their respective profiles 12, 14. In this way, variations in the cover width can be detected.

It will be appreciated that the vertical spring loading of beam 220 by springs 250 ensures good contact is made between the wheels 300, 320 and the respective recesses of the profiles 12, 14 and also allows for compensation for the gradual wear of the wheels 300, 320 until they are eventually replaced. hi other alternative embodiments, profiles other than, or in addition to the outermost profiles are measured. Also, as will be understood, while the above embodiments have been described, if indirectly in reference to measuring cover width in relation to crests of profiles, other embodiments may be configured for measuring cover width in relation to troughs of profiles. Also, while the laser positions are fixed on the beam 160 at predetermined distances apart with respect to the type of profile sheet they are measuring, in alternative embodiments, the lasers may be laterally movable on the beam 160 such that they could track any change to lateral displacement of the profile they are measuring. hi any embodiment described above, variation of cover width beyond predetermined acceptable limits may trigger an alarm at a display station, or the apparatus and controller may be in a feedback loop by which an upstream roll stand responds to cover width variation by adjusting its setting to correct the cover width, or an upstream pre-marker station compensates for to the detected variation.

While the invention has been described in reference to its preferred embodiments, it is to be understood that the words which have been used are words of description rather than limitation and that changes may be made to the invention without departing from its scope as defined by the appended claims. hi the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.