EX60-2 Thumb Circuit

[mutti_wilson]

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.

 

[excavator]

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?

 

[mutti_wilson]

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.

 

[mutti_wilson]

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.

 

[mutti_wilson]

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?

 

[uffex]

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

 

[excavator]

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?

That looks very close to what they used.

 

[excavator]

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.

 

[mutti_wilson]

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.

 

[mutti_wilson]

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

Thanks for that doc. Looks like some nice light reading this evening.

 

[uffex]

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

 

[mutti_wilson]

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
View attachment 225004

That's the exact setup I have. Are those caps available or do they need to be machined like the doc states?

 

[uffex]

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

 

[mutti_wilson]

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?

 

[mutti_wilson]

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.

 

[mutti_wilson]

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.

 

[uffex]

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

 

[mutti_wilson]

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.

 

[uffex]

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

 

[uffex]

I will look tomorrow for a good illustration