Thwaites Dumper?

[Howburn]

Hi I am looking for advice on this Dumper, can anyone tell me what it is, I think it is a Thwaites.

And does anyone have experience of the hydraulic steering; I am having trouble getting my head around it.

I have also posted on the Classic Machinery Network, if anyone else would like to follow it.
Thanks.

 

[cazl1994]

its artic steer isn't it same as all the dumpers
not a clue about the make tho!

 

[Howburn]

Yes it is arctic steer, but what confuses me is how the valve operates. It has been connected to a steering box with a rod and couple of ball joints and you would expect that the further you rotate the rod on the valve it would progressively steer more one way to the other.

The rod that has the spines on that sticks out of the valve is only supported on the outside face, the inner end that operates the spool valves is unsupported and has some sideways movement. For a long time I thought I was missing something I thought there may have been a cam or such to work on each spool and the opposite one would return due to spring pressure. It seems to me that this small amount o sideways movement may be what controls the ram, not rotational as you would expect.