Below: Bird’s eye view of the chassis (grey) showing RHS 150 x 50 2400 mm wide and slightly over 6 metres long, depending on the thickness of the vertical posts (3mm or less, with posts 2, 3, 4 and 5 being back-to-back (3mm x 2 = 6mm). This will mean the rear of the trailer will have a step down (the thickness of the floor plywood) of say 30mm, which is desirable because it allows for a rear door to overlap thus no driving rain would flow into the trailer from below.
The gold colour shows the plywood sheets.
To do: Calculate total weight to determine load capacity of the axles. Trojan sells a 2200 kg Duratorque set for $1,200. If torsion suspension is used, it would be feasible to weld a SHS beneath the spreader (number 4) that would allow the Durotorque to slip in and be held by a pin. If it does not add a lot of cost, two more such sleeves could be welded to both ends… when parked on site, the middle Durotorques could be unpinned, pulled out and inserted at the end corner. With two sets, the unit could then sit on tyres. Alternatively, such slots could be used for solid braces welded at a 90° angle. If this is complicated or adds too much expense, examine alternatives including conventional springs as CC does now.
It is expected the CC design using a removable drawbar provides a security element since it is harder for an opportunist to steal the unit.
Below is is a detail showing how to affix the vertical members (metal posts or studs) to the chassis. In order to work with the 150×50 chassis, the corner posts may have a 26 x 100 profile rather than the midpoint (and short end wall) posts at 26 x 26. This presents a more attractive aesthetic that frames the unit, and it allows for a stronger fixing with a 20 mm access hole in the bottom of the chassis rail whose centre is 63 mm from the end.
If it is not difficult to do, prior to folding the flat steel into the U channel, perhaps have the CAD/CAM machine punch a series of screw holes (4mm) about 13mm from the end at 300 mm centres. Then if plywood or composite glass is inserted, the screws can join each sheet of plywood with the next. Otherwise, the plywood must be trimmed, or the U channels bolted back to back, with say a 5mm gap (1205 mm separation) allowing 2.5mm on each side for the bolts. It is possible to tack weld the U channels back to back, but unless this is something that can be done automatically, it slows down manufacturing and adds another step. In addition to these 4mm holes, there should be a hole for a M10 bolt at the bottom, below the plywood that fixes to the chassis, and an equivalent way to fix the top of the post.
Next:
Top plate: How are the posts connected at the top? One option is to run a 6m steel beam that mechanically fixes to the posts and to 2.4 perpendicular beams. Another may be to join with >1.2 m U channels, perhaps wider so they slip over the posts (for example, inner slot of 26mm, which if 3mm steel, means a 32mm outer web.
Note: The prototype will have solid walls on three sides and a roller door at the end. The second two test units will have one side wall completely open (unless a support post is needed in the middle). These two units will have one with a left side open wall and the other a right side open wall. They will be placed side by side with a crane, and (to ensure they remain as “vehicles”) will then have a series of “G-clamps” that hold the two units together. They may have a rubber strip between them. This makes a 28.8 floor area, which is below the 30m² spec that does not require a building consent. Argument 1: It’s not a building because it is excluded under Section 8 of the Building Act 2004. Argument 2: If it is considered a building, it does not require a consent, provided it complies with the Code.
To do: Design the connections
Roof: It is expected the roof frame will have horizontal beams that match the floor spreaders (joists), every 1.2m on centre. It is possible for a DIY to affix plywood on the top and then a single waterproof membrane (such as pond liner). However, in prototype one, on top of the flat framework, a gable roof (two equal 25 degree angles) will add 1.5m long metal roof rafters, giving a more open cathedral feeling inside and a more attractive aesthetic. Note however, that this may make the mobile unit wider than the permitted 2.55m LTSA width. Thus, it may no qualify for a WOF (best to get a 3-year WOF first) and when relocated on the road would require the extra placards and handling of a Category One oversize. On the second / third units to be clamped together, a skillion (shed) roof would have matching left and right sides to create the appearance of a gable roof.
To do: Design the connections
If it possible to do this in 6.082m length as 3mm thick angle with holes to match
