installing hydraulic thumb

[Uamauka]

Hi,

I am going to install a hydraulic thumb on an Ingersoll Rand backhoe. Hydraulics are open center. I have read several threads and I think I like the idea of using a solenoid diverter off of the bucket section with a momentary switch for the thumb. I am confused about which valve to use, single or double, how to wire the switch if using a double, or how to route the hoses if single. Also where should I install a relief valve for the thumb?

Also are my current hoses and fittings metric? If so what are my simplest cheapest solutions in that regard?

Thanks,

 

[J_J]

Here is a selector/diverter valve you can use.

SAE 8 15 GPM DOUBLE SELECTOR VALVE 12 VDC P15544-1

http://www.surpluscenter.com/_MoreSpecs/i9-5117.pdf

A SPDT-CO (Single Pole Double Throw Center O)
switch can be used to switch the solenoids.

It can be mountrd just about abywhere, even close to the cyl you are diverting.

 

[polarred21]

This looks like a good deal, have you had good luck with this vendor?

 

[Uamauka]

Thanks. Any suggestions as to what I should look for in a relief valve?

 

[J_J]

This should work.

1/2" NPT 30 GPM 1500-3000 PSI RELIEF VALVE RV-H4

http://www.surpluscenter.com/Hydrau...0-3000-PSI-RELIEF-VALVE-RV-H4-9-6135-50-H.axd

 

[Uamauka]

Thanks for the help. OK now it gets a little tricky. I have figured out that my machine's hydraulics are metric DIN. Where can I find adaptors to the SAE ports on the selector valve? Or alternatively selector valve and relief valve that are already metric? And where can I find reasonably priced metric hydraulic hose? I know I can get hoses made locally, but if I have to do a bunch of hose this will get expensive? Any ideas?

 

[J_J]

British (BSP) and Metric Fittings

 

[Uamauka]

hammer hydraulics 101 please



For installing the thumb, I have decided against mounting the valves out on the dipper, so I want to use the existing hoses that are plumbed for an accessory hammer. If I am to use these hoses, then I wonder if I should choose a solenoid control valve and run it to a rocker switch, rather than the selector valve run off the thumb valve as I had planned. Thing is, I don't understand enough about the routing and what is going on with the hammer hydraulics on my machine. So I have drawn a diagram of the routing of the hoses involved. Please school me on what is going on and my best options. I do not have or need a hammer for this machine, so keeping the one way accessory in the system is not required.

Thanks.

 

[J_J]

Re: hammer hydraulics 101 please

Is your hammer flow a steady flow or a pulsating flow?

If it is a steady flow, the just use the solenoid to feed the thumb. It will operate at full force, with no feathering. Just touch a momentary button to move the thumb.

Is the hammer spool the first or last spool in the system.

Do you know if you can use multiple at the same time? If they are in parallel, each spool operated will get part of the flow, making it fast or slow.

 

[Uamauka]

I am afraid I don't know the answer to these questions. I was hoping the diagram would shed light on what I have. I think the hammer is the last spool in the system. The machine's main relief valve is in the loader stack, and the lower of these hoses feeds the lower main valve of the backhoe stack, and the hammer hoses seem to be bypasses of the outlet section with the solenoid in between.

I was under the impression that this is an open center system, though I can operate more than one function at a time, for instance the boom and the dipper- in which case both are very slow.

I have no idea it if the hammer was a pulse or steady flow. I only know that it functions with a pushbutton switch on the joystick which has only 2 wires coming off switch.

 

[J_J]

Just connect the valve to a cyl and test the function.

 

[Uamauka]

Not sure what I would be testing for hooking up a cylinder. I know the hydraulics are one way, and I will need two way for the thumb. I know the existing solenoid is screwed into a block that has only two hoses attached. I don't follow how specifically I would feed off of it to operate the thumb.

 

[J_J]

I did not realize you only had one path for the fluid.

Then what you need is a one spool valve to operate the thumb cyl. Feed the spool valve with the solenoid flow.

One other option is to use a SA cyl with a spring to return the thumb to the rest position. Then you could use the solenoid to feed the thumb . Similar to a hyd press.

 

[Uamauka]

Did you see the diagram attached to post #8? The hoses I want to use to lead out to the thumb are teed into the outlet hose and the hose downstream of the solenoid respectively. So when you say feed the spool valve off of the solenoid flow, it is not clear where to attach which hoses. This is my first time working on hydraulics. I try to figure things out by what I can find on the net and in the service manual, but so far the information I have come across does not make it clear how to proceed with the setup I have. If the diagram I posted is not clear as to what I have, perhaps I should post some photos.

 

[J_J]

How many ports on your solenoid valve.

I am assuming that fluid flows into the solenoid valve and out to the return line until you energise the valve at which time, the flow follows another path.

Is that the one path you want to use.?

In your drawing, it seems you have teed off the pressure line.

You have another acc line that tees into a return line. Is that a line you added

Do you have two acc lines?

 

[Uamauka]

How many ports on your solenoid valve.

---Just 2 large ports.

I am assuming that fluid flows into the solenoid valve and out to the return line until you energise the valve at which time, the flow follows another path.

---That is also what I was guessing after making up the diagram, the other path you refer to, I suppose consists of my two accessory hoses

Is that the one path you want to use.?

---I would use any path but I do need to tap into those accessory hoses somehow, even if it means just disconnecting them and putting plugs where they are teed in. But then I would still need a supply to tap into. I would like to use the following type of valve and not have to tap into any of the existing control valves. I believe that would be easiest with the best outcome. But I have to know how to rearrange the plumbing to hook it up given the existing setup. However, please tell me if you think there is a better way.

12 VDC 10 GPM OC DA SOLENOID VALVE

In your drawing, it seems you have teed off the pressure line.

You have another acc line that tees into a return line. Is that a line you added

Do you have two acc lines?

---I have not added anything. This is the way the machine was when I bought it. No other accessory lines and as far as I know the breaker hydraulics was a factory option. It is these tees and bypasses partly that has me confused in the first place.

thanks

 

[J_J]

Since you want to control a DA cyl, if you don't need the solenoid, then remove it and add a single spool valve to control the thumb.

The PB or OUT from the BH valve will feed the thumb valve.

Tank line goes to tank.

PB from the thumb valve goes to the 3pt.

 

[Uamauka]

first picture shows backhoe valve stack with accessory hoses in foreground

Second picture shows outlet section in foreground; the smaller teed in pipe is one of the accessory hoses. The larger pipe runs to the solenoid

Third picture shows the other side of stack. The main valve of the stack in foreground. The lower hose leads to the respective lower port of the main valve on the loader stack, which is the main relief valve for the machine.

Fourth picture shows solenoid. The second hose on the solenoid leads to the fifth picture.

In the fifth picture, the hose in foreground is the tee that goes over and ties into the main hose going from the main loader valve to the backhoe stack. Also in this picture, the larger and smaller connections lead to the solenoid and the other accessory hose respectively. What doesn't show up in the photo, is that the pipe also runs back to the tank.

All this is what I was trying to show in the diagram.

 

[Uamauka]

Ok it is starting to make sense, except I'm still not sure what to do with all these teed off hoses. Right now all I need to do is figure out exactly what to buy in the manner of valves, hoses, adaptors and plugs, since the metric adaptors are going to have to be ordered. The thumb itself should be arriving any day.

 

[Uamauka]

Since you want to control a DA cyl, if you don't need the solenoid, then remove it and add a single spool valve to control the thumb.

The PB or OUT from the BH valve will feed the thumb valve.

Tank line goes to tank.

PB from the thumb valve goes to the 3pt.

---What is the 3pt?

thanks