Member - Royce posted:

That's what I need. What brand? Where from?

I don't want to do any engineering/welding etc. I'm using a second tray that slides onto the existing one and then hinges at the rear. It will be over the gooseneck [5th wheel] ball in the centre of the tray which I don't want to remove.

So I will make sure that there is a suitable place for the bag and lift from there. A couple of chains so that it doesn't go too far and a couple of props to make sure it doesn't fall down when I least expect it. I'll also have a couple of emergency jacking points to get me out of trouble if needs be.

Then of course I'll have the exhaust jack to use elsewhere!

One of my many plans...

Thanks Royce

Member - Royce posted:

I appreciate the concern. I will hasten slowly, and abandon all plans if the unforseen is seen before the unforseen occurs, which of course is impossible because it's unforseen.... see?

But seriously, thanks for your worries.... I'll be very careful.

Mike Harding posted:

I know you're nobody's mug Royce but exhaust jacks are a bit of a danger even when used for their intended application and reports of them bursting are common. However with a ton or two of sand (whatever) on the back of a truck and a sudden drop from 1.5m? I dread to think of the forces involved when it decelerates rapidly as it hits the truck chassis.

How will you assess the aging process of the bag? Their design is for very occasional use over a period of (what?) five? years but in a tipper application it will be used much more, I assume. Protection from the elements - cold, UV, heat. Nah, don't do it Royce.

How about an electric motor driven screw drive?

Mike Harding

Member - Royce posted:

You are certainly talking sense... I'm slowing down on the idea.

Mind you, I dropped a round bale on the old effie yesterday from the back of a semi.... she survived... but I was a bit worried.

So.. I will need to address the chance of failure and dropping.... hmmm Okay, I have a few ideas.

My current bag has been used many times over 18 years, and still works well.

The bag for this purpose would not remain on the tray but be packed away when not in use.

Still, my resolve is shaken.... I'm easing up on my passion....

I'll sip an ale and walk around the truck and thinks some more....

Ta

Mike Harding posted:

>You are certainly talking sense

Got to be a first time for everything! :)

I'll give it some thought too... it's an interesting mechanical problem - especially for an electronics engineer! :)

Mike Harding

PS. I assume the electric / hydraulic motor option is too expensive?

Member - JohnR (Vic)&Moses posted:

Must be a few spare hoses pepper, I have one too. We could make up a long lead version.....

Member - Royce posted:

Where to mount and lift from... also, lifting a dead weight rather than rolling sliding weight.

Member - JohnR (Vic)&Moses posted:

Pete, sounds interesting to think about the pulleys and sky hooks required to succeed on that one.

Member - Vincent A M (NSW) posted:

Its quite std & many an engineer's sign of on them if they are done the right way, & many councils & electricity suppliers & hire company's use them.
I have made lift bags that are used at airports to lift jumbo jets & for bridge & mine collapses all on exhaust fumes. yes there are some that do shocking work & are unsafe & that happens in all trades i,m sorry to say