Pivot dumper forwarder

[andy cobb]

I've just bought a 5 ton thwaites dumper with the hope of mounting a hiab 650 on it and making a timber bunk on the front.

Wondering if anybody here had done similar or could think of a better way than the 1 I've got planned.

Was thinking of removing the steering column and mounting the hiab at the front of the rear unit, leaving the entire front unit to be a bunk, hoping I can work it so that the skip can also be swapped for the bunk easily so I can fit a clam shell and use it for on the construction side as well . Would remount the steering column on the hiab base somewhere as its only hydraulics and electrics.

Sorry it's so long winded but as its pissing it down I'm hoping there's a few on here who can offer some advice.

[Breezeblock]

to put a hiab on where the steering column goes would need a fair bit of strengthening I would think also if you have the hiab over the bunks when your travelling the swing circuit would need to be free flow in neutral which would then be a pain when you are loading on a camber I think you would be better with an extended front body and mount the hiab on that what lengths are you planning on carrying

[andy cobb]

Never considered the hiab following the bunk!

Was hoping to get 12 foot lengths on so would need a 8 foot bunk I guess.

Wonder if hiab could rest with grab on something at rear of machine or would that leave hiab joint too high for travel in woods?

[aspenarb]

I have done this on a forward control thwaites goliath, the hiab is the problem when unloaded. Its so top heavy that it tips the frame onto the stops on anything other than level ground. The only way around this would be to ballast that part of the chassis. The bit with the engine,steering and seat is ok and firmly on the ground but the bit past the swivel is too floppy. I was going to try some springs and shocks between the lateral swivel points to try and control it before I throw the towel in. Nothing wrong with this arrangement if you want a forwarder thats runs around a flat even woodland track.

 

 

Bob

[andy cobb]

Another option could be to mount it at the rear end, the hiab would still have enough reach I think and the engineering would be simpler but it still doesn't solve the problem of where to put the grab when moving.

[andy cobb]

I have done this on a forward control thwaites goliath, the hiab is the problem when unloaded. Its so top heavy that it tips the frame onto the stops on anything other than level ground. The only way around this would be to ballast that part of the chassis. The bit with the engine,steering and seat is ok and firmly on the ground but the bit past the swivel is too floppy. I was going to try some springs and shocks between the lateral swivel points to try and control it before I throw the towel in. Nothing wrong with this arrangement if you want a forwarder thats runs around a flat even woodland track.

 

 

Bob

 

Had never considered that either.

Machine will have to operate on some slopes but nothing too steep.

Do you think the hiab is better on the rear unit for stability?

[aspenarb]

Had never considered that either.

Machine will have to operate on some slopes but nothing too steep.

Do you think the hiab is better on the rear unit for stability?

 

 

It really needs to go on the ballasted bit where the engine and gearbox is. That would solve all the problems and make a decent little mini forwarder. The only issue to overcome on a pivot steer is where the hiab will rest when on the turn.

 

Bob

 

Edit: if you are cutting it about it may be worth extending the chassis and prop on the load area , this will move the axle further back and make it more stable when loaded with the longer lengths. Keep us posted on progress.

Edited February 12, 2017 by aspenarb

[andy cobb]

After listening to the help from here I'm thinking now of mounting it at the very rear of the machine and removing the legs so I can lower the hiab as much as possible to keep cog down then fitting pivoting legs just behind the wheels and lowering the roll frame as much as possible. Does anybody know if a valve of some sort exists that would allow the grab to follow when in transport but could then be closed to stop free flow for loading. Could a pair of pressure relief valves be piped into the slew circuit that could then be locked out?

[dent]

After listening to the help from here I'm thinking now of mounting it at the very rear of the machine and removing the legs so I can lower the hiab as much as possible to keep cog down then fitting pivoting legs just behind the wheels and lowering the roll frame as much as possible. Does anybody know if a valve of some sort exists that would allow the grab to follow when in transport but could then be closed to stop free flow for loading. Could a pair of pressure relief valves be piped into the slew circuit that could then be locked out?

 

Surely just a tap between the two sides of the slew control closed when in work open when in transport

[Breezeblock]

Surely just a tap between the two sides of the slew control closed when in work open when in transport

yep that would work