</font><font color="blue" class="small">( Guys,
there are a couple of recent threads going about the same subject.
This inquiry is aimed at no one in particular.
I just grabbed the most recent post out of convienience.
I have a question concerning the actual use of a hydraulic thumb.
I understand the thumb cylinder is used to actuate and retract the thumb. What happens when the "grip" is closed? Will the bucket curl cylinder fight the thumb cylinder and force the fluid against and past the valve spool? How is this compensated for? Doesn't this have a profoundly diminishing effect on the "grip" pressure.
Answers please.)</font>No expert here but from what I have seen druing use. The hydraulic pump only has so much to offer so when that is at or over it's capacity the implements start to lose pressure and push/pull force so it is a balancing act with these smaller tractors. There are also pressure relief valves on most of the spools that allow the pressure to by pass the spool before damage can be done. At least thats my understanding although I may be wrong.
</font><font color="blue" class="small">( Shouldn't the thumb travel "over center" into a mechanically locking position instead of relying solely on the cylinder pressure applied?
Answers please.)</font>No reason to. Once the cylinder is in the position you want, you release the lever and the spool locks the fluid in place which holds the cylinder with out having to feed any more form the pump.
</font><font color="blue" class="small">( So, from the above you can see that I'm a bit of a fibber, I did say I had A question. Sorry. I was thinking about this during the ride in and I'm not sure the traffic lights I crossed were actually green, and I ramble.
Thanks for your patience and answers,
Martin
)</font>No problem. Like I said this is all from what I know which is by all accounts, not much. /forums/images/graemlins/grin.gif
there are a couple of recent threads going about the same subject.
This inquiry is aimed at no one in particular.
I just grabbed the most recent post out of convienience.
I have a question concerning the actual use of a hydraulic thumb.
I understand the thumb cylinder is used to actuate and retract the thumb. What happens when the "grip" is closed? Will the bucket curl cylinder fight the thumb cylinder and force the fluid against and past the valve spool? How is this compensated for? Doesn't this have a profoundly diminishing effect on the "grip" pressure.
Answers please.)</font>No expert here but from what I have seen druing use. The hydraulic pump only has so much to offer so when that is at or over it's capacity the implements start to lose pressure and push/pull force so it is a balancing act with these smaller tractors. There are also pressure relief valves on most of the spools that allow the pressure to by pass the spool before damage can be done. At least thats my understanding although I may be wrong.
</font><font color="blue" class="small">( Shouldn't the thumb travel "over center" into a mechanically locking position instead of relying solely on the cylinder pressure applied?
Answers please.)</font>No reason to. Once the cylinder is in the position you want, you release the lever and the spool locks the fluid in place which holds the cylinder with out having to feed any more form the pump.
</font><font color="blue" class="small">( So, from the above you can see that I'm a bit of a fibber, I did say I had A question. Sorry. I was thinking about this during the ride in and I'm not sure the traffic lights I crossed were actually green, and I ramble.
Thanks for your patience and answers,
Martin
)</font>No problem. Like I said this is all from what I know which is by all accounts, not much. /forums/images/graemlins/grin.gif
