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Title:
PRODUCTION OF CLADDING SHEETS
Document Type and Number:
WIPO Patent Application WO/2009/012518
Kind Code:
A1
Abstract:
A method and an apparatus for producing a plurality of roll-formed cladding sheets for building a structure, such as a roof, are disclosed. The method includes optimal sequenced production of sheets from strip, with square cuts being made to the strip to form sheets, and then angle cutting of selected square cut sheets that comprise multiple smaller sheets nested together to form smaller sheets, with the smaller sheets having angle cuts at one or both ends of the sheets.

Inventors:
STARK GRAEME (AU)
Application Number:
PCT/AU2008/001048
Publication Date:
January 29, 2009
Filing Date:
July 18, 2008
Export Citation:
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Assignee:
BLUESCOPE STEEL LTD (AU)
STARK GRAEME (AU)
International Classes:
B21B15/00; B21D43/28; B26D5/00
Foreign References:
AU2006202113A12006-12-07
AU2005205780A12006-06-01
Attorney, Agent or Firm:
GRIFFITH HACK (509 St Kilda RoadMelbourne, Victoria 3004, AU)
Download PDF:
Claims:

CLAIMS

1. A method of producing a plurality of roll-formed cladding sheets for building a structure, such as a roof, which includes the steps of:

(a) inputting data relating to a design of the structure into a computer program that translates the design data into designs of a plurality of separate cladding sheets that have the correct size and shape to be placed directly onto a support frame and assembled together to complete the cladding of the structure and produces a schedule for roll-forming strip and thereafter cutting roll formed strip into the sheets , with the schedule being determined in accordance with at least one of the rules described herein;

(b) roll forming the strip,

(c) square cutting the roll formed strip with a cutting assembly into a plurality of separate cladding sheets in accordance with the schedule; and

(d) angle cutting the remaining cladding sheets , i.e. the sheets that include two or more than two cladding sheets nested together, with a cutting assembly and forming a plurality of separate cladding sheets having required final shapes in accordance with the schedule.

2. A method of producing a plurality of roll-formed cladding sheets for building a structure, such as a roof, which includes the steps of:

(a) inputting data relating to a design of the structure into a computer program, such as an Applicad

Roof Wizard program, that translates the design data into designs of a plurality of separate cladding sheets that

have the correct size and shape to be placed directly onto a support frame and assembled together to complete the cladding of the structure and produces a schedule for roll-forming strip and thereafter cutting roll formed strip into the sheets ;

(b) modifying the schedule produced in step (a) in accordance with at least one of the rules described herein ,

(c) roll forming the strip,

(d) square cutting the roll formed strip with a cutting assembly into a plurality of separate cladding sheets in accordance with the modified schedule; and

(e) angle cutting the remaining cladding sheets with a cutting assembly and forming a plurality of separate cladding sheets having required final shapes in accordance with the modified schedule.

3. The method defined in claim 1 or claim 2 wherein the angle cutting step is carried out in the factory in which the strip is roll-formed or at an end-use on-site, such as a building site.

4. The method defined in claim 3 wherein , when carried out in the factory, the angle cutting step is part of or directly linked to a roll-forming line or is separate altogether save for sharing the computer program to cut the sheets properly.

5. The method defined in any one of the preceding claims includes transferring all of the square cut cladding sheets to an angle cutting assembly and selectively angle cutting only those cladding sheets that require angle cutting, in accordance with the rules.

6. The method defined in claim 5 includes packing the cladding sheets after square cutting the strip and angle cutting the sheets .

7. The method defined in any one of claims 1 to 4 includes separating (i) the cladding sheets that have been square cut into the required final shapes, and (ii) the remaining cladding sheets , i.e. the sheets that include two or more than two cladding sheets nested together into two separate groups and angle cutting the sheets in group (ϋ) •

8. The method defined in claim 7 includes packing the cladding sheets in group (i) and packing the cladding sheets in group (ii) after these sheets have been angle cut in separate packs or in mixed packs .

9. The method defined in any one of the preceding claims includes marking the roll formed strip in accordance with the schedule prior to square cutting the strip in locations on the strip that require angle cuts .

10. The method defined in any one of the preceding claims includes cutting the roll-formed strip while the strip is being processed on a roll-forming line.

11. The method defined in any one of the preceding claims includes branding each cut or marked cladding sheet to identify the sheet so that it can be differentiated by the marked identification from the other cladding sheets that are required to build the structure.

12. The method defined in any one of the preceding claims wherein the computer program is capable of generating quotations to supply cladding sheets to build a structure .

13. A method of producing a plurality of roll-formed cladding sheets for building a structure, such as a roof, which includes the steps of optimal sequenced production of sheets from strip, with square cuts being made to the strip to form sheets, and then angle cutting of selected square cut sheets that comprise multiple smaller sheets nested together to form the smaller sheets , with the smaller sheets having angle cuts at one or both ends of the sheets.

14. An apparatus for producing a plurality of cladding sheets for building a structure, which apparatus includes :

(a) a roll-forming line for roll-forming a flat strip, for example wrapped in a coil, into a roll-formed profile ;

(b) a square cutting assembly for cutting the roll-formed strip into a plurality of separate cladding sheets having square cuts on the ends of the sheets ; and

(c) an angle cutting assembly for angle cutting selected square cut cladding sheets into separate cladding sheets .

Description:

PRODUCTION OF CIADDING SHEETS

The present invention relates to cladding for building structures, particularly roofs and walls, using roll-formed metal cladding sheets .

The present invention relates particularly to a method and an apparatus for cutting profiled metal cladding sheets such as roof or wall cladding sheets to their final shape .

The apparatus of the present invention can be part of an existing manufacturing set-up, such as a roll- forming line, or it can be a plurality of separate manufacturing set-ups that operate in accordance with the method of the present invention to produce cladding sheets .

The present invention was made during the course of further research and development work in relation to the inventions that are described and claimed in Australian patent 2004201410 (hereinafter referred to as "the Australian patent") and Australian patent application 2006202113 (hereinafter referred to as "the Australian application") , both in the name of the applicant.

The disclosures in the Australian patent and the Australian application are incorporated herein by cross- reference .

The references herein to the Australian patent and the Australian application are not to be taken as indications that the inventions described and claimed in the Australian patent and the Australian application are part of the common general knowledge in Australia.

Roof and wall cladding sheets for houses, factories and other buildings are often manufactured from profiled sheet metal such as steel strip. The Australian patent and the Australian application describe methods of producing cladding sheets that improve the efficiency of various parts of the manufacture, supply and installation of such cladding sheets , leading to the potential to reduce the total installed cost of the cladding sheets .

The Australian patent describes an invention of a method of producing a plurality of roll-formed cladding sheets that have pre-cut or pre-marked ends .

The invention of the Australian patent includes a method of producing a plurality of roll-formed cladding sheets for building a structure, such as a roof, which includes the steps of:

(a) inputting data relating to a design of the structure, such as a hip, gable or other type of roof of a building, into a computer program that translates the design data into a series of cutting operations of a cutting assembly for cutting strip having a roll-formed profile into a plurality of separate cladding sheets that have the correct size and shape to be placed directly onto an underlying frame and assembled together to form the structure/

(b) roll forming the strip; and

(c) cutting the roll-formed strip with the cutting assembly in accordance with the cutting operations and forming the plurality of separate cladding sheets .

In addition, the invention of the Australian patent includes a method of marking a roll-formed strip to define at least part of the perimeters of a plurality of

cladding sheets for building a structure, such as a roof. The method also includes cutting the roll-formed strip on the marked perimeters to form the plurality of separate cladding sheets.

In one embodiment of the Australian patent, non- squared, i.e. angled, ends of sheets are marked on roll- formed strip on a roll-forming line (with a result that a number of the sheets may include two "sheets" joined by an angled marking) , the strip is then square cut on the line using end shears, and angled cuts are made as required on an installation site (or in a separate operation - could be cut in a factory on a wet day, for example) . This method has been referred to as a λλ pre-marking" method.

The method of the Australian patent makes it possible to reduce the total installed cost of roof and wall claddings . The method includes (a) the use of computer programs, particularly CAD systems, which improve the quoting and ordering of cladding sheets, (b) steps to mark or cut steel strip into sheets of required final shapes as part of a manufacturing process, and (c) steps that produce sheets in an optimal sequence so that the sheets can be stacked easily in a suitable order for use by a roofer to facilitate installation on site.

The Australian application relates to an invention that was made by the applicant during the course of further research and development work in the field of the invention described and claimed in the Australian patent .

The research and development work considered a range of issues, such as computer programs that are available for scheduling roll forming of sheets. These programs include the Applicad Roof Wizard program developed by Applicad Australia.

The Applicad Roof Wizard program and other programs known to the applicant schedule the roll forming of roof cladding sheets on a roll former in an order that aims to reduce wastage. However, the programs do not necessarily schedule roll forming in an order that is easy for a roll former operator or a roofer to deal with the roll formed sheets. Specifically, the programs do not produce roll formed sheets in an order that can be packed in the reverse order required by a roofer. As a consequence, either the roll former operator has to shuffle the sheets at the end of a roll former line into packs, thus slowing and complicating the process and taking up more floor space, or the roll former operator simply packs the sheets in the order produced and the roofer has the time-consuming task of sorting sheets on site. At the moment both the roll former operator and the roofer are dealing with an unnecessary level of complexity.

The invention described and claimed in the Australian application is based on the realisation that there is a better way of scheduling the roll forming of roofing sheets than is possible with current programs such as the Applicad Roof Wizard program.

The Australian application describes a set of rules about roll forming that allows a roll former operator to produce and thereafter pack pre-cut or pre- marked roll-formed sheets after roll forming in the order produced by the roll former without shuffling the sheets . The rules were developed by the applicant. The rules simplify and speed up the process and make it possible to produce and pack sheets in the order that the roofer (or person constructing a wall) might want to use them, thereby speeding up the roofing (or wall construction) process and saving space on site .

The Australian application applies the rules to a roll forming schedule produced by a program, such as the Applicad Roof Wizard program, and produces a modified roll forming schedule that roll forms sheets in an order that minimises or eliminates the need for sorting after roll forming and results in sheets that have square and/or angled cuts being packed in a logical order for the person cladding the structure, such as a roofer.

The Australian application describes that, generally, the logical order includes placing the starting sheets for each roofing plane on top of the relevant packs .

The rules described in the Australian application include the following rules (hereinafter referred to as "the rules") .

1. Look for pairs of structural planes with similar properties , eg similar pitches and similar numbers and lengths of hips in the case of roof structures .

2. Match any sheets on these planes that require angle cutting to minimise wastage - in other words, operate a production sequence so that there is one angle cut common to two successive sheets .

3. Use pairs of planes that have opposing laying directions. If only one such plane has a critical laying direction based on a viewing direction or prevailing winds, for example, use the opposite laying direction on the other plane in the pair .

4. In the case of roof structures, where a plane runs from a hip to a valley, and the sheets are a generally rhomboidal shape, it is usually not necessary to pair it

up with another plane, as it can be produced and packed with little wastage.

5. In the case of roof structures , where a section of a hip roof runs into another (larger) plane of similar pitch, it is normally possible to merge the smaller hip with the plane that it meets to gain greater efficiencies in manufacture .

6. In the case of roof structures, where a gable runs into another roofing plane, the two sides of the gabled roof section can be produced efficiently if they have opposite laying directions . Where a smaller gable section runs into a larger pitched roof to form valleys , it may be possible to merge the valley detail on the smaller gable roof planes with the valley detail on the larger pitched roof for greater efficiencies . Typically this will mean swapping sheets from one side of the gabled roof to the other .

7. Number all sheets produced, normally by branding in some form, and normally on an underlap, to indicate structural plane number and sheets position on the plane.

8. Sheets are ideally packed in the order that they are produced and close to how they will be used on site and to allow individual packs to be located in convenient spots on site.

9. The above sequencing mentioned in item 8 minimises the need to sort packs and lay sheets temporarily on bare ground, thus reducing the possibility of damage.

10. Sheets can be produced and packed in an order that minimises damage from cut edges.

11. Ends of packs can be produced to have mainly square

cuts , with angle cuts generally contained in the middle of packs for safety .

12. Sheets are seguenced in production and packing such that they are in the logical order in packs that a person cladding a structure wants to use them. In the case of roof cladding, on most planes there are one or two preferred sheets that the roofer will want to start with, then roofing proceeds from those sheets .

13. When sheets are paired up with sheets from another plane, to minimise wastage, it is possible to turn these two sheets end-for-end in roll forming where the profile is not totally symmetrical, depending upon which side of the roll former produces the underlap. This will not affect wastage or practical use on site. For example, if sheet 1 from roofing plane 1 is a perfect match for sheet 7 from plane 2, they can be paired up by producing 1-1 then 2-7, or 2-7 followed by 1-1, this means turning the pair of sheets end for end but simply changes which side of the sheets the underlap is on.

The Australian application offers benefits in safety and efficiency both in a manufacturing site and on an installation site.

In summary, the Australian application describes that sequencing the production of sheets correctly makes it possible to minimise material wastage and develop simple and efficient steps for cutting strip with square and angle cuts and stacking sheets produced in the method. The method simplifies materials handling in a factory, leading to gains in both efficiency and safety. Furthermore, the method has the advantage of being be easily retrofitted to an existing processing line such as a roll former. Alternatively, the method can be used as a separate method after the manufacturing of the materials .

The Australian application shows that it is possible to efficiently produce cladding sheets by nesting together sheets of similar or matching shapes, such that there is little or no wastage when producing roofing sheets for a roof containing hips and valleys , for example. By generally ensuring that the nested sheets are based on the pairing of no more than two roofing planes for manufacture, a simple method can be developed to cut and stack these sheets into individual roofing planes.

In general terms , using the methods outlined in the Australian patent and the Australian application makes it possible to stack sheets easily in an order that a roofer needs to use them, thus improving safety and efficiency on site .

As is evident from the above discussion and the documents themselves , both the Australian patent and the Australian application rely on square cutting and angle cutting strip to form cladding sheets having required final shapes .

The term "square cutting" is understood herein to mean cutting strip in a direction that is perpendicular to a manufacturing direction of a manufacturing line, such as a roll forming line.

The term "angle cutting" is understood herein to mean cutting strip in a direction that is at an angle that is between (a) an angle that is perpendicular to a manufacturing direction of a manufacturing line, such as a roll forming line and (b) the manufacturing direction .

The present invention includes making only square cuts with a cutting device such as a shear as the first and in some embodiments the only cuts made to a strip on a

manufacturing set-up, such as a roll-former. This is consistent with conventional practice for standard roll- formers that only produce cladding sheets with square cuts at both ends of the sheets . This reduces the formed sheets to manageable sizes . The square cut sheets include sheets that have square leading and trailing ends and require subsequent angle cutting to separate each sheet into two or more smaller sheets of required shape. The nesting of the smaller sheets having non-square ends into larger sheets that have square cut ends minimises wastage of material . The subsequent angle cutting of these sheets separates the sheets at the interfaces of the nested sheets. The nested sheets include, by way of example, roofing sheets of complex shapes from different roofing planes (or in some very specific cases from the same roofing planes that are generally rhomboidal in shape) .

The present invention also includes separately cutting these sheets that each include nested sheets (i.e. two or more than two sheets each requiring at least one non-square end) so that they can be either installed directly onto a roof (or other structure requiring cladding) or stacked in roofing planes or some other logical grouping for subsequent installation.

The present invention is based on a realisation that marking to final shape for example as proposed in the pre-marking method of the Australian patent might not be needed if nested sheets from different roofing planes are produced by square cutting roll formed strip on a manufacturing line and are subsequently separated by shear cutting or some other process , such as plasma or laser cutting during or after manufacture on the manufacturing line.

More specifically, the present invention is based on a realisation that after any forming (such as roll

forming) and square cutting has been completed, if the nested sheets (i.e. the two or more than two nested sheets) that remain joined are separated on a manufacturing line, such as a roll former, it is then possible to develop a simple stacking process, but only providing that a suitable method has been used to sequence the sheets for nesting and manufacture, as described in the Australian patent.

In general terms, the present invention provides a method of producing a plurality of roll-formed cladding sheets for building a structure, such as a roof, which includes the steps of optimal sequenced production of sheets from strip, with square cuts being made to the strip to form sheets, and then angle cutting of selected square cut sheets that comprise multiple smaller sheets nested together to form the smaller sheets, with the smaller sheets having angle cuts at one or both ends of the sheets .

The term "optimal sequenced production" is understood herein to mean the preferred production sequence in any given situation having regard to factors such as wastage of material and subsequent handling of cladding sheets in a production factory and on a building site.

The present invention provides a method of producing a plurality of roll-formed cladding sheets for building a structure, such as a roof, which includes the steps of:

(a) inputting data relating to a design of the structure into a computer program that translates the design data into designs of a plurality of separate cladding sheets that have the correct size and shape to be placed directly onto a support frame and assembled

together to complete the cladding of the structure and produces a schedule for roll-forming strip and thereafter cutting roll formed strip into the sheets, with the schedule being determined in accordance with at least one of the above-described rules ;

(b) roll forming the strip,

(c) square cutting the roll formed strip with a cutting assembly into a plurality of separate cladding sheets in accordance with the schedule; and

(d) angle cutting the remaining cladding sheets , i.e. the sheets that include two or more than two cladding sheets nested together, with a cutting assembly and forming a plurality of separate cladding sheets having required final shapes in accordance with the schedule .

The present invention also provides a method of producing a plurality of roll-formed cladding sheets for building a structure, such as a roof, which includes the steps of:

(a) inputting data relating to a design of the structure into a computer program, such as an Applicad

Roof Wizard program, that translates the design data into designs of a plurality of separate cladding sheets that have the correct size and shape to be placed directly onto a support frame and assembled together to complete the cladding of the structure and produces a schedule for roll-forming strip and thereafter cutting roll formed strip into the sheets;

(b) modifying the schedule produced in step (a) in accordance with at least one of the above-described rules ,

(c) roll forming the strip,

(d) square cutting the roll formed strip with a cutting assembly into a plurality of separate cladding sheets in accordance with the modified schedule; and

(e) angle cutting the remaining cladding sheets with a cutting assembly and forming a plurality of separate cladding sheets having required final shapes in accordance with the modified schedule.

The angle cutting step of the above-described methods may be carried out in the factory in which the strip is roll-formed or an end-use on-site, such as a building site.

Moreover, when carried out in the factory, the angle cutting step may form part of or be directly linked to a roll-forming line or be separate altogether save for sharing the computer program to cut the strip and then the sheets properly.

The method may include marking the roll formed strip in accordance with the schedules prior to square cutting the strip in locations on the strip that require angle cuts .

The method may include transferring all of the square cut cladding sheets to an angle cutting assembly and selectively angle cutting only those cladding sheets that require angle cutting, in accordance with the rules. In that event, the method may include packing the cladding sheets after both operations of square cutting the strip and then angle cutting the sheets.

The method may include separating (i) the cladding sheets that have been square cut into the

required final shapes, and (ii) the remaining cladding sheets , i.e. the sheets that include two or more than two cladding sheets nested together into two separate groups and angle cutting the sheets in group (ii) . In that event, the method may include packing the cladding sheets in group (i) and packing the cladding sheets in group (ii) after these sheets have been angle cut in separate packs or in mixed packs .

The method may include cutting the roll-formed strip while the strip is being processed on a roll-forming line.

The method may include branding each cut or marked cladding sheet to identify the sheet so that it can be differentiated by the marked identification from the other cladding sheets that are required to build the structure.

By way of example, the cladding sheets may be branded with consecutive numbers .

By way of further example, the cladding sheets may be branded with a plane number and a laying sequence number for the pack.

The roll-formed strip may be a steel strip.

The roll-formed cladding sheets may be any suitable profile. For example, the cladding sheets may be corrugated sheets having successive crests and troughs when viewed in transverse section and one underlap side edge and one overlap side edge. The cladding sheets may also include one or more ribs separated by pans and one underlap side edge and one overlap side edge.

The computer program may be capable of generating

quotations to supply cladding sheets to build a structure.

The present invention also provides a method of producing a plurality of roll-formed cladding sheets for building a structure, such as a roof, which includes the steps of:

(a) inputting data relating to a design of the structure into a computer program that translates the design data into designs of a plurality of separate cladding sheets that have the correct size and shape to be placed directly onto a support frame and assembled together to complete the cladding of the structure and produces a schedule for roll-forming strip and thereafter cutting roll formed strip into the sheets, with the shedule being determined in accordance with at least one of the rules described herein ;

(b) roll forming the strip,

(c) square cutting the roll formed strip with a cutting assembly into a plurality of separate cladding sheets in accordance with the schedule ;

(d) packing the cladding sheets that have required final shapes /

(e) angle cutting the remaining cladding sheets , i.e. the sheets that include two or more than two cladding sheets nested together, with a cutting assembly into a plurality of separate cladding sheets having required final shapes in accordance with the schedule; and

(f) packing the cladding sheets produced in step (e) .

According to the present invention there is also

provided an apparatus for producing a plurality of cladding sheets for building a structure, which apparatus includes :

(a) a roll-forming line for roll-forming a flat strip, for example wrapped in a coil, into a roll-formed profile ;

(b) a square cutting assembly for cutting the roll-formed strip into a plurality of separate cladding sheets having square cuts on the ends of the sheets; and

(c) an angle cutting assembly for angle cutting selected square cut cladding sheets into separate cladding sheets.

The cladding sheets may be any suitable profile .

For example, the cladding sheets may be corrugated sheets having successive crests and troughs when viewed in transverse section and one underlap side edge and one overlap side edge . The cladding sheets may also include one or more ribs separated by pans and one underlap side edge and one overlap side edge .

The roll-forming line may include an uncoiler for a coil of strip and a series of roll-forming stands for successively roll-forming strip unwound from the uncoiler into a roll-formed profile .

The cutting assemblies may be any suitable cutting assembly, such as a shear cutter, a plasma cutter, a laser cutter, or a water-jet cutter.

The cutting assemblies may include two or more cutters positioned in relation to the roll-forming line and selectively operable depending on the type of cuts

required .

The present invention provides opportunities for optimal nesting and sequencing of production so that it is possible to develop a simple method for sorting and stacking of sheets after the method such that they are easy to use on site .

The following general discussion highlights important points in relation to the present invention.

The method of the present invention includes optimal sequenced production of sheets from strip, with square cuts made to the strip to form sheets , and then separate cutting of selected square cut sheets, such via a mechanical shear, plasma cutter, laser cutter or water jet cutter, at any required angle to separate the nested sheets into smaller sheets having angle cuts at one or both ends of the sheets for stacking and transport.

With optimal sequencing of the sheets and then cutting as described above, sheet stacking can be performed in a simple way such any there is little or no sorting required and the sheets can be stacked in an order that an installer wants to use them. This reduces the space required in a factory and on a site, as well as improving efficiency and safety.

If the method used to separate any nested sheets requires a mechanical shear, the shear can make cuts at any angle provided that the shear is able to rotate in the plane of the manufactured material . The combination of such a shear and an optimal sequencing method to allow for simple and efficient stacking of sheets is described in the Australian patent. Other cutting processes such as plasma or laser cutting are also described in the Australian patent. One advantage of plasma, laser or

water jet cutting is that they can be used to separate nested sheets even if the shape of these sheets is complex. Mechanical shears generally cannot be used for complex cuts . Plasma cutting is generally more cost effective than laser cutting, but laser cutting often provides better cut quality.

In the method of the present invention, where the square and angle cutting of strip to form sheets is carried out as separate operations, with one operation confined to square cuts and a later operation making angled cuts of nested sheets, then the information required to perform these separate operations needs to be transferred to the operations . This can be done in a number of ways, for example in ways that are similar to the methods used to transfer information to the roll forming or other manufacturing line whereby everything is done in one processing line described in the Australian application. As described in the Australian application, the calculations of final sheet shapes are performed using a computer-aided design package, such as Applicad' s Roof Wizard program. Information from a program is transferred to a control system of a manufacturing facility, such as a roll forming line, to convey information such as the length of each required sheet for manufacturing and cutting. Along with this, information is available to determine where the sheets need to be cut to separate sheets that have been nested together for efficiency. These cuts will often be angled cuts .

This information transfer can be done directly to the separate operations or by capturing the relevant information on the sheets at the time of manufacture in one operation and using this information at a downstream operation. This could be done by placing a bar code with the relevant information on the sheets at the time of manufacture to indicate where any subsequent cutting has

to take place. Alternatively, an appropriate mark could be placed on an underlap of a sheet during the manufacturing process. In such cases, it is preferable that the information be captured in machine-readable form for use on the subsequent cutting process .

Mien cladding a building with sheets that are not rectangular in shape, any edges that are not parallel or perpendicular to the production direction of the cladding material are often hidden from view, with the exception of valleys. Where edges are hidden, it is possible that they do not require the same cut quality as those sheets edges that are exposed to view and exposed to the external environment. However, all edges must be of reasonable quality to ensure safety for factory workers, installers and others and to ensure adequate durability in the case of steel sheeting, for example.

Preferably the most suitable cutting technology for separating nested sheets will be chosen based on a combination of the complexity of the shapes of the nested pieces and the quality required on the edges of the cut sheets, as well as other factors such as cost and speed of cut.

Once nested sheets have been separated into their final sheet shapes, the separated sheets can be either used immediately or stacked into packs in a logical order such as into packs for separate roofing planes, for example. One practice is to install roofing or wall cladding sheets one plane at a time, and therefore stacking the sheets into roofing planes simplifies practices on site. By integrating this method with optimal sequencing of the sheets through the manufacturing process, the individual sheets can not only be stacked in logical groupings such as into roofing planes , but they can also be stacked such that they are in the order that

the roofer wants to use them. This can reduce or eliminate further sorting in the factory or on the job site, thus improving both efficiency and safety.

The method of stacking the individual sheets after nested sheets have been separated from one another can be completed manually or can be automated. A simple form of automation would involve the use of two or more drop-stackers . Individual drop stackers are often used at the end of processes such as the roll forming of metal claddings .

A pair of drop stackers may not be sufficient to allow all sheets to be stacked into separate roofing planes and may not allow all sheets to be stacked in the correct order for the roofer . However, a method based on a pair of drop stackers, combined with some other simple mechanical handling equipment, allows all sheets to be stacked in the correct order for subsequent installation. This additional equipment would need to allow a group of sheets , such as those required to make up the triangular portion of one plane adjacent to a hip on a roof, to be produced and stacked while other material is produced, then subsequently moved and stacked with other material from the same plane.

An alternate process to drop stackers could use air handling or other equipment to move each sheet once nested sheets have been separated. One such process involves sheets being manufactured, any square cutting being completed, then any nested pairs of sheets that remain connected travelling along a run-out table for subsequent processing and/or stacking. These nested pairs of sheets could then be moved offline to be separated at an independent station or could be separated on line.

Once this separation has been completed, air handling or other suitable processes can be used to move sheets to any

necessary location for subsequent stacking and/or use.

The present invention makes it possible to significantly simplify processes such as ordering, manufacturing and installing roll formed roofing and wall cladding sheets manufactured from sheet steel or other materials. This can save labour, reduce material wastage, and increase safety. These benefits can lead to a reduction in the total installed cost of a building or can make the processes of manufacturing and supply of materials more attractive , or both of the above .

Another key advantage of the method of the present invention described here over other methods of cutting sheets to their final shape is that the method described herein offers the ability to perform most or all cutting of sheets in a factory, without having to reduce the speed of the manufacturing process to perform complex cutting and stacking operations. This leads to efficiencies in the factory and, by using simple sequencing and stacking techniques, this also means that it is possible to achieve efficiency on the job site. This combination can further increase the opportunities available to reduce the total installed cost of metal cladding systems that include sheets other than rectangular in shape .

Many methods that have been considered previously to achieve the benefits identified here have' a difficulty that small sheets cannot be easily removed from the process . This can slow down the operation and introduce safety concerns . The present invention does not suffer from these problems. By leaving nested sheets joined together in the initial square cutting process and then subsequently separating these nested sheets in a separate cutting process, it is possible to incorporate sufficient room and suitable techniques to safely remove and pack

small pieces .

The present invention is described further by way of example with reference to the accompanying Figure which is a diagram that illustrates one embodiment of an apparatus for producing a plurality of cladding sheets in accordance with the present invention .

The apparatus shown in the Figure comprises a roll-forming line that includes marking and cutting assemblies for marking and cutting a roll-formed cladding sheet to any required shape for subsequent installation.

With reference to the Figure, flat steel strip is unwound from a coil 5 and passed successively through a series of roll-formers 7 that progressively roll a required profile in the strip. By way of example, the profile may comprise a series of lengthwise extending flat pans separated by upstanding ribs with side edge formations to allow adjacent subsequently formed cladding sheets to be positioned in side by side overlapping relationship .

The roll-formed strip emerging from the last of the roll-formers is moved past a position sensor 17 for sensing the position of the strip, a marking assembly 9 that marks locations on the strip that require angle cuts and/or marks sheet numbers on the strip, a first cutting assembly 11 in the form of an exit shear which square cuts the strip, i.e. cuts the strip in a direction perpendicular to the direction of movement of the strip, at required positions and forms cladding sheets . Some of these cladding sheets are marked at selected locations to show where angle cuts are required to separate each sheet into two (or more than two) angle cut sheets.

The cladding sheets emerging from the exit shear

11 are passed to a sheet handling station 25.

The cladding sheets that do not require any further cutting, i.e. those sheets that are intended for use as square cut sheets, are sorted and packed as required at the sheet handling station 25.

The cladding sheets that require further cutting, specifically angle-cutting, are passed through the sheet handling station 25 to a second cutting assembly 13. The assembly 13 is shown as a part of the roll forming line. In other embodiments, the assembly 13 is in a separate part of the factory in which the roll forming line is located. In still further embodiments the assembly 13 is on a building site. In any event, the assembly 13 is selectively operable to cut the sheets to produce cladding sheets having required angle cuts. Specifically, where the assembly 13 angle cuts each sheet into two sheets, at least one end of each cut sheet is an angle cut end.

The cladding sheets emerging from the second cutting assembly 13 are passed to a sheet handling station 15 and are sorted and packed as required. For example, the cladding sheets may be separated and packed with other sheets from their respective roofing planes in separate packs , i.e. each pack comprising sheets of one plane .

The above-described apparatus is controlled by a computer program that includes appropriate rules that:

(a) translate design data for a structure, such as a roof of a house, into a series of cutting operations of the cutting assemblies 11, 13 for cutting roll-formed strip to form the cladding sheets ;

(b) in part controls the roll-forming line; and

(c) in part controls the cutting assemblies 11, 13 and cuts the roll-formed strip to form cladding sheets having the required shapes.

The operation of the cutting assemblies 11, 13 is responsive to the requirements of the programmed series of cutting operations and the actual operation of the roll forming line at any given point in time, as monitored by the sensor 17. It is noted that the present invention also extends to arrangements in which these operations are separate .

It is evident from the above that, depending on the type of end profile required for a cladding sheet, one or both of the cutting assemblies 11, 13 may be operated. For example, in a number of situations it may only be necessary to square cut the ends of the roll-formed strip. In these situations, operation of the exit shear 11 only is required. In other situations it may be necessary to form angled straight cuts on one or both of the ends of the roll-formed sheets . In these situations operation of the cutting assembly 13 is appropriate, for example as described above.

The cutting assembly 13 may be a shear cutter that is operable to move along the length of the roll- former line with each roll-formed sheet that requires angle cutting and form the angled cut or cuts on the eheet during the course of such movement.

In other situations it may be necessary to form more complex cuts on the ends of the roll-formed sheets . In such situations, operation of both cutting assemblies 11, 13 may be appropriate to complete the cuts.

Alternatively, a cutting assembly capable of cutting complex shapes such as a plasma cutter or water

jet cutter may be used at station 13.

Many modifications may be made to the present invention described above without departing from the spirit and scope of the invention .




 
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