I'm planning to add a thumb to my EX60-2 and need a hydraulic circuit to run it. I'm thinking of using the unused offset boom spool. It'll require me to fab up a pedal and run a cable to the spool since it's not hydraulic. This seems to be the most fool proof way but it will be pedal actuated which isn't the worst. I'm used to that from another machine I run. I'd add a relief valve so I could tailor it to the bucket hydraulics. If I were to go electric over hydraulic and run it off buttons on a joystick what would the options on the control valve be? I would just do a solenoid setup. I don't need proportional control unless it wasn't a big cost difference which it most likely would be. I'm trying to keep the cost down as this is just a machine for around my house. It's hard to justify spending too much on something that doesn't pay me.
It's been a while since I've worked on those and can't say that I ever paid attention to one mounted on an offset boom machine. But on the standard boom EX60- 2&3 models they used a small cylinder mounted inside the right rear door. Using pilot oil and running a DO3 valve which activated the cylinder which, if I remember correctly was just a small Bimba brand air cylinder. Where in Washington are you located?
I'm in Woodland. There is a small clevis pin on the bottom of the control valve that the cable as I can see it hooks up to. It only moves about 3/8" in both direction from it's detent.
Also was that the way the aftermarket added a thumb circuit? I don't see anything in the schematics about that valve being used for anything else.
You'd use a cylinder like this on pilot pressure instead of air? https://www.grainger.com/product/SPEEDAIRE-8-mm-Air-Cylinder-Bore-Dia-5TKW9 When the solenoid is not actuated would the valve on the control block return to detent?
Good day mutti You may find this attchment of interest click on the link its a bit heavy so I cannot post it on the forum. ttps://drive.google.com/file/d/1yMgSzsQFcr4bUY8_sq1lJkqFyfglRNF6/view?usp=sharing Kind regards Uffex
That looks very close to what they used.
I'm up by the Canadian border and know of two or three machines in the area. If you want to take a short drive I can show them to you to give you an idea how it was done.
Your version of a short drive is a bit than mine I understand the theory behind what they are doing. I don’t have a great understanding of hydraulics which makes my head spin more than it should. The pilot pressure on my machine is 485psi as per what I found in the manual. That cylinder is 145psi. To keep the pilot pressure in the rest of the system at spec I’d need to put a check valve and a relief valve in the supply to the new solenoid right? The other question I have is that I understand a directional solenoid will return to center position when not switched. Does that position relieve all pressure in the solenoid? If that’s the case the spring on the spool would return the air cylinder to a neutral position which would allow the thumb to stay fixed. if you can remember were these guys using on/off solenoids or proportional valves? I’m thinking I would control the speed of the thumb with a flow restriction if I used an on/off type.
Thanks for that doc. Looks like some nice light reading this evening.
Good day If your machine is similar to the dash 3 you may be able to "Do it yourself" see attched spool conversion. Kind regards Uffex
That's the exact setup I have. Are those caps available or do they need to be machined like the doc states?
Good day Mutti Im afriad you have to make those yourself it is not so difficult or if you have a friendly guy with a lathe who likes a challange - you need to measure the stroke ect. Be aware that it appears that the Hitachi intention was that this spool was intended to be more of a On-Off than a proportional control like the other spools - converting to pilot may result in a sharp response. Stay safe Uffex
Couldn't the cap that's already there be used? Just weld a fitting to the cap and run a line to it? On the clevis side the cap just needs to allow for travel right? There isn't anything else to worry about with the stroke?
Here's a picture of my control valve. The red cap is the other side of the spool with the clevis. The green is a relief that is in line with the spool. Would this be a relief specifically for that valve? If so that would be great to be able to tune it to the bucket cylinder. I'm going to look through the manual to see if I can find anything about that relief.
I have access to lathes and mills and I'm not scared or a challenge. Thanks for all the help so far. I've been a little unsure which direction is the best to go and you all keep surprising me with options.
Good day Mutti Yes if I may suggest in your shoes - remove that cap - I believe you will find it is the same hole spacing as the opposing end - that helps as you have a pattern - measure the stroke and make the cap long enough to clear the spool - I not sure about using the exsisting cap with a fitting but to run up two while you are at it seems a fair bet - a quarter inch pipe thread in each end plus an Oring ledge in the face and you should be ready to go. Another possibity if you have a dismantler near by you could check out if there is any suitable caps.Sorry yes stroke and travel are the same diamension According to our information that option sppool is devoid of port / overload / shock relief valves If I can help some more please come back. kind regards Uffex
Perfect. Thanks for the information. I will be working with my friend this week re-boring and bushing my bucket and I'll bring that cap with me and see what we can make up. Is that cap any more complicated than a dust cap? On the schematic cross section I see the spring and it looks like there might be more going on but hard to tell. Either way I'll pull the cap and go from there.
Hi Mutti The spring is attached to the spool it has a collar and slide so the spring returns the spool from both directions - the spring will stay attched when you take the cap off, no its not complicated so dont be worried. Take out the two screws it should just come away, you can lodge the spool in the housing just to stop it creeping out while you make up the caps, provided the cable is attched the spool will not move. The spool has seals so leakage should not be a problem. KR Uffex
I will look tomorrow for a good illustration
Good day Mutti We have assembled some information taht may help. Kind regards Uffex
That is fantastic. I will get back to you with some information from my end. As far as the solenoid goes. Is there any reason to have to use a 24v solenoid or can I just use a 12v as there are more options? Do all the electronics operate on the machine operate on 24v? This seems like it would be the ticket for 24v. https://www.surpluscenter.com/New-A...ctional-Hydraulic-Solenoid-Valve-9-220233.axd Along with this sub plate https://www.surpluscenter.com/Hydra...3-Parallel-CC-Subplate-SFP-10101-9-4070-1.axd A couple relays and diodes along with control buttons and I should be good to go right?
I ordered everything up and I'll keep you all in the loop. Uffex has been really helpful as well.
Does anybody know what the threads on the control valve are? I’m getting an O.D. of .810 and it’s not lining up with any charts I’ve seen. It’s straight thread with an o-ring.
Good day Mutti I have some information from later Hitachi could be the same. KR Uffex
I brought a plug into a hydraulic shop and the best we could come up with was an SAE #10. It's a bit loose on the threads but the o-ring will seal nicely.
I'm going to be using a needle valve to adjust thumb speed. Should I put that before or after the relief valve?
Good day Mutti Not sure regarding the plug but you can improve On/Off operation by using one direction chokes at the solenoid valve pilots not so expensive, i would suggest rig it first and try to see what needs doing and take it from that point. As always we can make an illustration to help. Kind regards Uffex
So I thought I'd follow up and report back on which route I went and how it works. Uffex was really helpful through this project. Much thanks to him. Parts List starting at the stick. Rocker Switch 24v Relay Terminal Blocks Wire Plug Connectors Solenoid - A & B ports vent to tank when centered. Sub Plate Needle Valve Cushion/Relief Valve Hoses/Fittings out to the end of the boom 3D printed switch housing. Looks a bit 80's but so does the rest of the machine. I decided to use a screw terminal block for easier fixes in the future. Wire from relay are coming in with water proof plugs on the right. Pilot pressure is coming from a T on the upper right. The solenoid is mounted with welded nuts to the back of the hydraulic tank. Tank drain T from the solenoid.
Continued... Machined caps that replaced the dust cover. Sealed to the block with a O-ring. Pilot pressure from the solenoid moves the spool. There is one on the bottom of the block as well. Long 1/2" BSPP to 5/8" JIC. JIC was used wherever possible. Needle valve is upside down to stay out of the way. Relief valve is mounted to a bracked I welded up. Notice the welded NPT fitting. I couldn't get that thing to stop leaking. Disregard the booger welds. It was dark and I didn't care anymore
Continued... Mocking up and welding up the thumb. Hoses and clamps. Another boom/stick shot. Notice the gray clamps on the boom. I modeled these up and printed them with PETG. It's a decently strong plastic and durable for outdoor use. The small bore clamps to the hard lines and the large bore grips the hose.
Final "Glamour" shot. She still needs some love.