I am getting a thumb for my machine and need to set the auxiliary relief to 2200 psi. Is it as simple as installing a gauge on the excavator auxiliary hydraulics (at the quick coupler) and operating the auxiliary valve and adjusting pressure accordingly for each side? My plan was just to put a gauge on the end of a quick coupler to check/adjust pressure. My excavator has a switch to operate between a hammer and other attachments, what does this valve change in the circuitry? Machine is a deere/hitachi 50.
Probably. Is it like a 50C or D? Yup Switch changes from one way flow for the hammer or say a mower or mulcher, to bidirectional flow for things like thumbs with one or more cylinders. YMMV
Which letter/dash number 50? Be advised that on the Deere/Hitachi the usual instructions for mounting a thumb have you plumb the barrel end of the thumb cylinder to the male quick coupler on the left side of the boom. We plumb them to the right side female coupler. The reason is the thumb usually requires the circuit relief to be set lower than what is required for your other attachments. Plumbing to the side I mentioned means you can have a circuit relief setting for your thumb without affecting the circuit relief setting for the other attachments.
Good day The file is a little to heavy to post here but if you visit the web site excatech.org > Library > adapted applications > H2 Thumb questions & answers you can down load or read. It is both safe & free. Kind regards Uffex
Its the zx50-U. (same as Deere 50ZTS) I don't have other attachments, so I was going to set the pressure the same on both circuits. ?
You don't have to plumb into the auxiliary circuit to get pressures. You can plumb into the pump outlet connection and read any pressure on the machine all in one place.
You only have to set the thumb pressure on the circuit relief that will be connected to the barrel end. The other relief should be fine where it is at which is set from the factory at approximately 2800-3000 psi. The reason for the lower pressure on the barrel end is the thumb should collapse if the bucket curl is forced against it to prevent the thumb cylinder rod from bending.
That makes sense. I didn't think about that. This is my first machine (home/hobby use) and while I feel I know my way around most things mechanical, I am definitely weak when it comes to hydraulics
Thank you for this, from what I understand I should not need to add a relief valve to my machine correct? I should be able to just adjust the pressure at the main control valve from what I understand?
Good day psi Our idea's best explained in the attachment whilst not to scale it should enable us to sing the same song, if you need more advice we are happy to help. Kind regards Uffex
I installed a thumb on my 50D. The switch in the dash changes the flow rate only. You still have a manual diverter valve for open tank for a hammer. I wanted to keep my higher pressure for my auger and didn’t want to add any extra crossovers so I just reduced the barrel end of the circuit and keep the rod end the same. Works fine with no additional crossover valves. Have seen menu set up like this.
Thanks! My machine is one model older, so I don't have the switch. I just have a footpedal.
You can adjust the stoppers under the pedal to slow the thumb down if it’s too fast. To lessen the flow
While on the same topic, would it be hard to wire in an electric valve to operate the thumb off of a joystick switch instead of the footpedal? I don't know if it would be worth it, but it would be nice
That's the way I always did them. You need a solenoid valve. I think we called them a D3 valve but it has been a long time since the last one I did. A supplier of hydraulic components can fix you up with what you need and how to plumb it. Your foot and leg will thank you for it.
Good day PSU Full instructions on the website excatech.com there are a number of choices you can operate in combination of bucket movement if that's your preference. Kind regards Uffex