BH65 Thumb Conversion Help

[J_J]

Assuming the hyd system is open center,

If the first valve uses all the fluid flow, then the next valve will not work.

If you only use, say, half flow for the BH, the other half is available for the thumb valve.

If the BH should be closed center, then each valve will have flow since they are all in parrallel.

 

[numerobis]

Assuming the hyd system is open center,

If the first valve uses all the fluid flow, then the next valve will not work.

If you only use, say, half flow for the BH, the other half is available for the thumb valve.

If the BH should be closed center, then each valve will have flow since they are all in parrallel.

exactly if the valve body is after the thumb couldnt not work if any bh function is fully activated...
if thumb use half flow... backhoe could still work...
if thumb is at full flow... the rest wont work... exactly as the backhoe...
if you have to ajust the spools continously to keep 2 functions working

there is no variable displacement pump or any load sensing + pressure compensation systems on thoses small machines
only the big backhoe and excavator have theses expensives systems...

i know somewhere i have the hydraulic shematic of the bh65 backhoe i will try to post it...



http://fr.scribd.com/doc/82938260/18/HYDRAULIC-HOSE-STABILIZER here is something that i found... if someone wants to add sandwitch to the bh65 valve body for a thumb

 

[J_J]

If you install the thumb valve first and reduce the PRV setting say, 2200 psi, so the BH does not over power, you limit your BH to the PRV 2200 psi setting on the thumb.

If the thumb valve is after the BH valve and the thumb setting is set 2200 psi, , there is no degradation to the BH, which could be set to 2750 and if the BH pushes on the thumb, the pressure on the thumb will relieve if you have work port reliefs.

It is also a simple thing to work the bucket and then the thumb , or set the thumb and then use the bucket .