Benefits

1. Cost benefit over flanged joins

Flange joins are a common form of prefabricated joining.

Mass production savings typically come from reducing materials input, reducing energy inputs, and reducing the number and complexity of required production and assembly operations including reducing machine time and labour input. Joinlox can deliver cost savings in all these areas when compared to a bolted flange.

In the case of a bolted flanged joint replacement like a pipe, cooling tower or pressure vessel the savings via a Joinlox join can be determined using the formula:

The cost of flange joins includes cost of: flange materials; moulding/pressing/cutting flange; punching/drilling/moulding bolt holes; machining/moulding grooves; welding/moulding/flaring attachments; bolts/washers/nuts/seals; time to fit seal and align, fit and tension bolts.

The cost of a Joinlox join includes cost of: Joinlox materials (slightly less expensive than for flanges), moulding/machining/pressing/punching castellations (similar or less expensive than flanges), moulding/extruding/pressing/punching the Joinlox key (significantly less expensive than cost of bolts); seal (same cost as for flanges); time to assemble join (90% plus time saving over flange assembly).

Joinlox joins are considerably less expensive than flanged joins. The labour time reduction in providing the designed joint tension and the reduction in the number and complexity of parts represent the main savings.

Miniaturization is a continuing trend in most industries because of the materials cost savings it brings. Joinlox joins can also be made more compact and aesthetically appealing than a flanged join. In some cases this will be more important than cost savings.

2. Input cost benefits for vehicle shells

Joinlox offers considerable savings when constructing joins for aircraft, road vehicles or water crafts. This is because the Joinlox key can form a significant part of the joint strength and substantially overcomes the slight material inefficiencies involved in lapping the castellations of the joints.

For instance, in constructing the fuselage of an aircraft, a series of curved plates may be joined to a series of annular stiffening ribs to create a ribbed cylindrical shell. Joinlox makes very efficient use of the hoop bracing value of a bonded Joinlox key. In effect, the Joinlox key that holds the joints together also forms the stiffening rib. With a Joinlox join, the thickening of the keyway hooks is not wasted material.

The hook support column passes in each direction under the key and the only ‘missing’ material is the clearance between these castellated hook shanks. If designed with the correct geometry these surfaces are totally backed by the underlying joint material. And if an appropriate adhesive is applied, the entire joint becomes both mechanically rigid and chemically bonded. Both mechanical Joinlox attachment and adhesive bonding should be used in mission critical aerospace and vehicle shell applications.

The stresses in the keyway hooks are concentrated in the ‘hook to shank’ and ‘part to shank’ attachment regions, so the hook shape and size can be designed to totally overcome the applied stresses as well as provide lateral support for the locking annular key. In this way a rigid joint which can resist vibrational and micro-movement wear and flexural fatigue stresses can be made at a lower cost using Joinlox.

We estimate that if only half of the approximately one million screws in a typical passenger aircraft were replaced by Joinlox joins the estimated saving would be $500,000 per aircraft.

3. Transport cost savings

Joinlox technology allows for the flatpacking of items, so they can be constructed simply at point of delivery. For instance, rather than transport water and wastewater tanks as finished products, they can be nested into each other, transported, and constructed at the destination, reducing transport costs considerably. The ability to flatpack, then transport, such tanks, can give a net return on Joinlox technology of between $680 or more per unit or more for export markets.

In a typical cylindrical pressure vessel with a welded torrispherical end cap, wall thickness in the Heat Affected Zone (HAZ) on either side of the weld determines the pressure rating of the vessel. The weld is typically thicker and stronger than the adjacent connection to the wall.

Traditionally, the stress on this wall section is predominantly resolved as a tensile stress because of the shape of the end cap. If the weld is replaced by a flanged joint welded onto both the cap and the wall, then bolted together, a bending moment is introduced which is significantly weaker than the tensile strength of the weld. The flange must be made thicker to provide the required bracing.

Further, the bolts are necessarily spaced apart and so must have a higher tensile rating than the parent material. The joint flange ends up being more than three times as thick as the wall section to provide an equivalent strength joint to a weld and annular depth of the flange can be 5-6 times the wall thickness. This sets a benchmark for the Joinlox pressure joint.

With a Joinlox join the design of the castellated hooks, and in particular the attachment region to their supporting shanks, is critical for a pressure vessel. They can be designed to produce a joint that is stronger than the parent material of the pressure vessel wall.

If the cylindrical pressure vessel’s cap is connected via a Joinlox join, and the cap and the cylinder walls are the same thickness, the join will be stronger than the wall. This takes into account the clearance gaps between the hook support columns. Since almost all the pressure forces are resolved as tensile forces and compressive forces, the load can easily be supported, provided the keyway hooks have sufficient backing to prevent bending.

Since the underside of the hooks can be backed by the underlying material, the pressure forces on the joint can be resolved with minimal deformation of the hooks to create a very rigid joint, with less material required than a bolted flange.

The joint pretension is set not by the deformation of the hooks, but by the flexural modulus and stress vector direction thickness (the ‘spring’) of the key material.

It should also be noted that rigidity is not always a desirable joint property. In some cases – for example with roads and bridges – it is desirable to have joints that will ‘give’ slightly on impact loads. Both very stiff and very springy joins can be made using Joinlox.

Joinlox technology greatly assists with making compact products. In particular, parts can be designed for nested or flatpack storage and transport.
Benefits include:

• Up to 80% lower investment in warehousing space
• Greatly improved transport efficiency
• Lower greenhouse gas emissions
• Lower embodied greenhouse gasses
• Easier handling
• Reduced mould costs because large parts can be made as composite parts
• Composite part segments can be made on smaller cheaper moulding machines

Joinlox greatly reduces the environmental impact of products. It reduces the materials needed in part joints, as well as the energy, and greenhouse gases, required to make, freight and dispose of Joinlox products.

Joinlox products can be easily disassembled and reused/recycled. Joinlox technology enables the servicing of previously discarded parts like fridge compressors and electrical solenoids, saving millions of tons of raw materials and greenhouse gases. Longer-lasting products means less landfill waste.

Joinlox technology enables stronger joins with significantly less materials. Forces applied in a Joinlox join are distributed evenly along the joint faces, eliminating high stress-point loads and enabling lighter-weight shell structures.

Joinlox can simultaneously reduce failure risks and costs. Joinlox enables the easier adoption of high-strength state-of-the-art composite materials. Fibre-reinforced plastics can be used to replace steel parts, removing the need for expensive long-term cathodic protection. Materials can be mixed and matched, such as glass-to-metal, elastomers-to-ceramics and plastics-to-rubber.

Joinlox technology means easier assembly and servicing, both in the factory and in the field.

In the factory:

• Positive self alignment of parts, largely eliminating assembly errors
• Faster construction and less energy required than welding or gluing
• Full strength achieved immediately
• No requirement for fiddly screws and fasteners, or complex jigs and robotics
• Stripping and over-tightening of screws and bolts no longer a concern
• Joint torque pressures automatically achieved with simple manual assembly or high speed robots
• Reduces factory overheads for quality assurance testing such as x-ray weld inspections

In the field:

• Easy and simple assembly and disassembly without need for welders and fitters
• Simple self-alignment of joint components
• Joins cannot be under- or over-tightened
• Design torque is automatic, even in the dirtiest field conditions
• Corrosion of bolts eliminated
• More robust and reliable than most traditional methods of field assembly and joining
• Reduced quality assurance testing of equipment ie. x-ray weld integrity testing of pipes
• Easier disassembly