I have a customer that purchased a new Cat 305.5E2CR excavator a while back along with a tilt bucket. He called me to come and check the pressure on the thumb, it was set at 3500psi so I backed it off to 2300psi. Now his tilt bucket will not hold a grade on a hard dig unless I turn up the pressure to 3500psi again. I'm thinking of putting a solenoid operated pressure relief block, set at 2300 psi, in the thumb closed line so when he is using the thumb he just has to flip a switch to drop the pressure. He never uses the thumb and tilt bucket together. I'm thinking the thumb cylinder is cushioned so the thumb open should be OK. Any thoughts on doing this or other ideas? TIA
So I assume that the current setup requires switching something to go from tilt to thumb function? I personally would incorporate whatever you are switching currently to go from tilt to thumb, in the same switch. This would assume the current switch is electric. Wire the solenoid to activate when you flip it to thumb function. Having a separate switch to lower the pressure would be something that gets forgotten and would be inconvenient when remembered. I am sure someone on here will have a more elegant solution!
Tilt bucket hoses get connected to thumb circuit at end of stick and a ball valve is turned.
If it were mine I would remove the manual valve and replace it with a solenoid valve, probably back under the hood-where the rest of the hydraulics reside. Then add the relief to the side going to the thumb, and a new set of hoses going out to the thumb. Bit of work, but at least it would be easy to use. The way it’s being used now would last about an hour n I would be in the shop replumbing it! That would drive me nuts to get out of the machine and do all that every time I wanted the thumb!
Good day Please see attached I hope it is of help. Kind regards Uffex
The good part about it is that there is no way of using the thumb and the tilt bucket at the same time. Tilt buckets are not made for thumbs.
Yes, I bet that could create some big messes if used at the same time!
Unless you have a kubota...i use my wrist and thumb all the time to place stackable limestone
Just put a pressure reducing valve on closing side of thumb cylinder...that way wrist can still get max pressue