A JOINT SYSTEM

TECHNICAL FIELD

The present invention relates to a joint system.

Particularly, although not exclusively, the present invention relates to steel structures which could be the framework of a portal system, rafter system, or any other structural element.

BACKGROUND ART

There are a number of companies in New Zealand and internationally which specialise in manufacturing buildings with a steel sub structure.

These buildings are typically constructed from a light weight "C" section frame which are joined at intersecting points by a range of fasteners and brackets.

United States Patent No. 20050120658 A1 discloses a joint structure for a building using thin and lightweight shaped-steel, and, in particular, provides a joint structure for fastening and fixing frame members made of thin lightweight shaped-steel to steel sills and a bolt joint truss structure for forming a main structure of a roof. This joint structure is also used to fasten a steel frame member to form a wall to a steel floor sill. The joint portions of the respective members are connected together to form a joint and a fastener is inserted into the joint through-hole to fasten and fix the respective members to each other.

JP 2004346614 A2 is a joint structure of steel column or steel pipe column and beam reinforcement. A joint bracket for screw reinforcement is fixed to a reinforcement fixation position on an outer face of a column flange of the crisscross steel frame column, a tip of a beam reinforcement composed of the screw reinforcement is screwed into the joint bracket to join the beam reinforcement with

the crisscross steel frame column.

US 6,920,724 discloses a bracket for a structural panel and a structural panel made with such a bracket. A bracket for use in fabricating steel structural panels has a first passageway for accepting a connecting member secured to a diametrically opposed bracket to introduce tension between opposing brackets in the panel. The brackets each have an additional second passageway to accept a connecting member for securing the brackets to a horizontal structural slab or other floor systems.

US 6,047,513 relates to a construction system for building a steel frame using steel members. Rafters form a roof portion of the steel frame, and a ceiling joist having two ends form a ceiling portion of the steel frame. Compression webs and tension webs, disposed between the rafters and the ceiling joists, distribute the load between the rafters and the ceiling joists. A peak bracket connects two rafters and a compression web together. Eave brackets connect the two unconnected ends of the two connected rafters to the ends of the ceiling joist. Compression brackets connect the pressure webs to the ceiling joist. A centre bracket connects two of the tension webs and one of the compression webs to the ceiling joist. Channel brackets connect one of the tension webs and one of the compression webs to one of the rafters and the ceiling joist.

Although the above existing systems work well from a structural perspective, there are a number of disadvantages associated with the use of brackets and fasteners to join the steel sub structures.

Investment

From an operational perspective, it can be difficult for a business to supply complete building systems.

Currently, the brackets and roll formed steel sections are manufactured by alternative suppliers. This is because the range of machinery required to produce the brackets and sections is vastly different, making the consolidation of supply uneconomic from an investment perspective.

Steel Cost

Conventional engineering design in most cases also calls for the brackets securing the joints to be twice as thick as the base frame material, as steel is sold by weight this equates to higher costs.

Freight

The heavy nature of the conventionally designed brackets also adds additional freight expenses to the overall cost structure.

Galvanising Costs

As the brackets are required to be thicker than the base material and pre- galvanised material can only be purchased up to 3mm thick, the majority of brackets also have to be galvanised separately, also adding additional cost and time delays to the process.

Training

In most cases the design and distribution of light weight steel buildings is limited to a few key wholesalers who distribute their product by way of franchising the rights to smaller locally based individuals. The present number of brackets and the various construction techniques and practises create complexities requiring constructors to undergo specific intensive training to bring them up to standard, again adding additional time and cost to the process.

It is an object of the present invention to provide a joint system which addresses

the problems highlighted herein with the prior art methods or at the very least provide the public and trade with a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is used in relation to one or more steps in a method or process.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF INVENTION

According to one aspect of the present invention there is provided a joint system for structural elements including:

at least two lengths of sheet material,

characterised in that,

one end of each length of sheet material is pre-cut at a predetermined angle

the angle of the pre-cut ends are such that the ends are configured to receive each other to join the sheet material lengths together without the requirement of a bracket to provide a self supporting system capable of forming a sub-structure of a building.

According to a further aspect of the present invention there is provided by a joint system for structural elements including:

at least two lengths of sheet material,

characterised in that,

one end of each length of sheet material is pre-cut at a predetermined angle such that the structural integrity of the materials remains, and

the angle of the pre-cut ends are such that the ends are configured to receive each other to join the sheet material lengths together without the requirement of a bracket.

According to another aspect of the present invention there is provided a method of joining structural elements,

characterised by the steps of,

a) pre-cutting one end of each length of sheet material at a pre-determined angle such that the structural integrity of the materials remains.

b) configuring and aligning the pre-cut ends with respect to the pre-determined angles to receive each other, and

c) joining the sheet material lengths together without requiring a bracket.

Throughout the current specification the term structural element should be understood to mean any weight bearing aspect of a structure.

In preferred embodiments of the present invention the structural element is a sub

structure or frame section of a building.

Throughout the current specification the term 'sub-structure' of a building is that which is directly attached to the foundations, and provides the structural integrity of the building. For example, Figure 1 shows a "C" sectional structure of three portal frames connected by steel purlins running elongated between the frames.

Once this structure is physically attached to the foundations, its design is such that it provides all the necessary skeletal strength for the building.

However, this should not be seen as a limitation on the embodiments envisaged for

this invention. Other structural embodiments envisaged include, but are not limited to frames of any structure either commercial or residential, furniture, shelving, trunking and glass houses.

Throughout the body of this specification the term sheet material is defined as material in the form of a sheet, the thickness being between 0.5 mm and 6.0 mm.

In preferred embodiments of the present invention the sheet material is galvanised steel.

The advantages of steel is that it is strong, malleable and readily available.

This should not be seen as a limitation of the present invention however, for other embodiments for the sheet material include aluminium, black steel, tin, or any other such material.

In preferred embodiments receiving ends of the sheet material are configured and formed into a "C" section.

However, this should not be seen as a limitation of the embodiments envisaged for this invention as any alternative configuration of sheet material could conceivably be used with this invention. For example, angle iron, U sections and box sections.

The following description outlines the use of "C" sections, but as mentioned above could easily apply to alternative configurations of sheet material.

A "C" section is a length of sheet material rolled with a cross-section in the form of a block letter "C" and includes a base and two upstanding sides.

The advantages of a "C" section is that it creates structural integrity along the length of the sheet material.

In preferred embodiments the "C" sections are formed by a roll forming machine.

Roll forming machines allow for fast efficient manufacture of large quantities of section with a minimal labour input. The sections can also be formed by using a Press Break.

In a preferred embodiment the "C" section may be pre-cut with a CNC Gantry Plasma Cutter.

In yet another preferred embodiment the "C" section may be pre-cut and gulleted in combination with a software interfaced CNC Gantry Plasma Cutter as it is roll formed.

Throughout the current specification the term gullet or grammatical variations thereof should be understood to mean a shaped cut applied to the material after is has been formed. To clarify the term 'gullet' the word notch or grammatical variations thereof may be used interchangeably with the word notch which should be understood to mean a v-cut or any type of shaped cut or indentation as made to the structural material.

In preferred embodiments the "C" section is gulleted to. retain the structural integrity of the material while allowing to fit in a complementary manner.

The advantages of shaping a cut or gulleting the material in this way is that a sufficient side of the first "C" section is pre-cut to accommodate the base of the second "C" section when in a joint area once formed.

The advantage of this shaped cut is the structural strength of the joint is

maintained.

The same principle is true of all joints. The inherent shape of the cut of the preformed material gives joints with the requisite structural integrity.

The key variables on when deciding where to gullet the material and the size of the gullet, are the width of the section being rolled (can vary from 100 mm to 400 mm) and the angle of the roof.

The size of the intersecting section impacts on the requisite size of the gullet to allow the two sections to intersect and the angle of the roof impacts at which point the gullet will be made on the intersecting section.

In preferred embodiments of the present invention the gullets may be of any angle to allow engagement of the two receiving ends.

The angles of the shaped cuts may vary according to the purpose of the joint system.

In one embodiment of the current invention the angles of the shaped cuts will be adapted to an apex of a building.

However, this should not be seen as a limitation on the embodiments envisaged for this invention. Other embodiments include the angles of shaped cuts adapted to section joints in boundary joists, haunch corners, floor joists, mitred joints or any other structural element.

In preferred embodiments the ends of each length of the "C" sections are pre-cut to fit in a complementary manner.

This allows the strength of the joint to be maintained by overlapping and interlocking of the sheet material.

In preferred embodiments the "C" section may contain a perforation. The perforation may be a hole of any shape or configuration and provide a fixing point

for the "C" section.

In preferred embodiments the perforations may be automatically inserted into the joint area of each end of the "C" section.

However, this should not be seen as a limitation on the number of perforations to be used in the current invention. There may be multiple perforations providing multiple fixing points.

In preferred embodiments a fixing means may be inserted into the perforations of overlapping lengths "C" sections to secure them in place.

In preferred embodiments the fixing means will be at least one nut and bolt.

However, this should not be seen as a limitation on the current invention. Further embodiments envisaged to secure the overlapping "C" sections include a Ramset ™ bolts, Rivets, Welding

This technology has a number of advantages over conventional construction methods used in the steel building industry.

The use of a Roll Forming machine in combination with a software interfaced robot makes it possible to cut and gullet the sections once formed. Providing a preformed joint from the original "C" section.

Consolidation of Supply

The pre-cutting (gulleting) and perforating of steel sections as they are roll formed enables the manufacturer to effectively incorporate the bracket at manufacture thus eliminating the need for a secondary supplier simplifying the process and eliminating additional costs.

Bracket Material

The use of thinner parent material to form the joints eliminates the need for separate brackets which are thicker than the parent material. Less steel simply equates to less cost.

Galvanizing

Because the joints are made from the pre-galvanized parent material there is no need for individual galvanizing, also a substantial cost and time saving.

Freight

The new joint design is substantially lighter than the use of conventional brackets and as such is much cheaper to freight.

Construction Efficiency and Training

The new system will also include ink marking which will allow each section to be individually marked allowing it to be easily matched to the corresponding section, again saving construction time, training and labour costs.

BRIEF DESCRIPTION OF DRAWINGS

Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1 : shows a diagrammatic representation of the overall assembly of one preferred embodiment of the present invention;

Figure 2: shows a diagrammatic representation of the "C" section side apex detail before assembly of one preferred embodiment of the present

invention;

Figure 3: shows a diagrammatic representation of the "C" section side apex detail of one preferred embodiment of the present invention;

Figure 4: shows a diagrammatic representation of the "C" section side mezzanine floor before assembly for the boundary joist of one preferred embodiment of the present invention;

Figure 5: shows a diagrammatic representation of the "C" section side mezzanine floor section for the boundary joist of one preferred embodiment of the present invention;

Figure 6: shows a diagrammatic representation of the "C" section side of the haunch corner detail before assembly of one preferred embodiment of the present invention; and

Figure 7: shows a diagrammatic representation of the "C" section side of the haunch corner detail of one preferred embodiment of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

With reference to the figures, there is provided a building with a steel structure and framework as indicated by arrow 1.

The building (1) consists of a side wall column (2), a portal frame (3) with two upper rafters (4) and (5), an apex (6) a haunch (7) and a mezzanine floor connection (8).

Manufacture

The steel section is manufactured from feeding a flat steel sheet into the Roll

Forming machine which gradually forms the desired shape as the material passes through a progressive set of internal rollers. Once the section is formed, the interfaced CNC Gantry Plasma Cutter ignites to cut and gullet the section to the desired shape.

Figures 2 and 3 show the "C" sections of the apex joints in more detail and is manufactured from 250 mm sheet material.

As detailed there is a large proportion of the original "C" section that has been maintained along the bottom edge to provide structural strength, but removed from the top edge to accommodate the intersection of the two sections.

In this case the strength of the joint is maintained by the residual section running through the bottom of the joint. As the pressure on the apex is downward from the roof, to fail the pressure would have to essentially push the sections through each other.

As also shown on figures 4 to 7, the same principle is true of all the joints. The method uses the inherent shape of the preformed material to form the joints with the requisite structural integrity.

The receiving ends of the two joints are cut at the required angles which are complementary to each other. For example, an apex that has an external 22° pitch has an internal angle of 158° and a haunch with an external angle of 79° has an internal angle of 101 °.

During this process the receiving ends are also perforated providing the fixing points for the joints. The holes are profiled by the CNC Gantry Plasma Cutter at the same time the material is being cut and gulleted to form the various joints. A typical distance apart between hole spaces is 160 mm.

Installation

The receiving ends are engaged by overlapping the "C" sections, aligning and inserting bolts into the perforations. The bolts are tightened with nuts securing the joints together.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope of the appended claims.