Parties, presents, food, drink, sleep, books, toys etc. etc. etc..
As if there aren't enough distractions already.
A few hours were found if not a great amount of energy and enthusiasm.
The lifting legs are now high priority. They need to be able to lift the "cabin" at least high enough to drive the truck "out from under" but also, because this thing is so damn high to begin with, to lower it down to a more stable and reasonable height where it can be used safely and comfortably.
Screw mechanisms, hydraulics, levers and all manner of different ways were considered to try and find an economical, simple, reliable method of actuation. Finally I realised that half of the items needed were already in use with the air supports on the chassis. These items are not needed when the cabin is taken off so can be utilised as actuators (with the addition of two more to make one ) at each corner.
There are always problems getting one piece of pipe to fit nicely inside another especially when they have a weld seam inside but 65 x 65 x 3 SHS isn't a bad fit inside 75 x 75 x 3 SHS so that's what I've chosen for this. These sizes are a little loose but it is difficult to remove the seam so it's not advisable to choose a closer fit even though different wall thicknesses are available. They work better in longer lengths as shorter ones have a tendency to tilt and "jam".
Having decided it's "air" I need to make a prototype to see if it actually works OK. The air-bags are rated at 1000kg each so they will be close to their limits and they have an extension range of 100mm. so multiple short lifts will be required. Test setup looks like this:
The lower sleeve I decided to completely fabricate from 100 x 5 flat bar and 65 x 5 flat bar as I could make it a closer fit on the lower section which dictates just how low to the ground I can get. With this setup it can be lowered to 125mm which is OK as I would block it up rather than have it sit directly on the ground (drainage) and is about the floor height of a container for loading. It raises better than it lowers but I think the addition of a shim strip would solve that.
Also it requires the welding of an extension on the back to slide into the support beams under the cabin which will help to hold the sleeve more upright and hopefully prevent the jamming.
With additional bracing gussets the final version looks like this:
No holes have been drilled at this point however a number of holes and slots need to be made for each step up, about 100mm as mentioned earlier. Also it is important NOT to allow the full weight of the load to bear on the airbag NOR to allow the airbag to stretch more than the recommended maximum so there will need to be limit stops provided as well.
Setting up the legs, which need holes at 100mm intervals, in the mill is quite simple and ensures the holes will be accurate in shape, size and position which is important for ease and security of operation apart from one small problem. The leg is too long to fit in the mill!!
A minor adjustment to the splash guards disposes of that problem!
Now all I need is a bit more enthusiasm.
Maybe if I stopped eating quite so much I might feel a little more like doing something.
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