Hydraulic joystick - would this work?

[jim_wilson]

A friend of mine has a hydraulic joystick that appears to come out of some type of bulldozer or other piece of construction equipment. There are 6 ports on the bottom of the joystick for what appear to be hydraulic connections. I was wondering if this could be used with the hydraulics on my BX23? Does anybody know anything about these types of devices - would they stand up to the pressure of the BX hydraulic system? My idea was to use the joystick to control a top-n-tilt setup for my BX - I managed to score some side link cylinders last year and that would leave just a top cylinder and some hoses and fittings to have a complete setup - if this joystick would work.

 

[Tractors4u]

</font><font color="blue" class="small">( that appears to come out of some type of bulldozer or other piece of construction equipment )</font>

</font><font color="blue" class="small">( would they stand up to the pressure of the BX hydraulic system? )</font>


If it came out of a bulldozer or a piece of construction equipment, I think it could handle a BX.

 

[MadReferee]

Do you have any info as to the type of valve? Open or closed center? Does it have power beyond? Is there a pressure relief on the valve?

It sounds like it's a 3-spool valve but there should be at least 2 or 3 more connections for the pressure inlet, tank output, and possibly power beyond outlet.

Usually dozers have a very high gpm rating, usually around 25 gpm. Your BX has less than 5 gpm so this valve might be a little too big and bulky.

 

[jim_wilson]

I guess what I wasn't sure of was whether a joystick like this was plumbed directly into the hydraulic system in it's original application - and could handle the full hydraulic pressure - or whether there was lower hydraulic pressure at the joystick and it was hooked up remotely somehow to the regular hydraulics.

 

[MadReferee]

Some fender mounted joysticks are cable operated whereby the joystick cables are connected to the actual valve. Kubota cab tractors have these. From your description you have a normal valve that is connected directly to the tractor hydraulics.

 

[jim_wilson]

I will have to see if I can get more info on the valve. I just looked at it really quick. There are only six ports on the bottom that are marked 1,2,3,4 , P and a marking I can't make out.

 

[MadReferee]

You have a 2-spool valve not a 3-spool. 1,2,3,4 are the work ports for the 2 spools (they go to the cylinders). The P port is probably the pressure inlet and the other port is the outlet.

It looks like you do not have power beyond port which would limit the functionality and how you can use it on your BX. That and the fact that it's probably way too big physically would eliminate it from my choices.

 

[moeh1]

I'm a hydraulics idiot, but I keep trying to learn. I've seen some devices similar to what you are descripting which are pilot systems to control actual large hydraulics, and are only rated at 500 psi, so do your homework

 

[jim_wilson]

Actually the size is not too bad - that is what got me thinking about using it in the first place. It would a much better size to fit somewhere on the BX than the typical multiple spools with multiple sticks setup that I have seen for top-n-tilt installs.

Since I am a bit of a hydraulics idiot myself I have a question - do I need to have power beyond? The reason I ask this is because what I was thinking of doing was simply using the hydraulic connections that are already located at the back of my BX23 for the backhoe when it is connected. There are only two connections so my assumption is that these are pressure inlet and pressure outlet (back to tank).
I have the maintainence manual at home - I suppose I could answer my own question by looking up the hydraulics circuits to see what the two connections are. I still don't know if this valve would handle the full hydraulic pressure of the BX system - I will have to do a little more research to figure that one out.

 

[MadReferee]

</font><font color="blue" class="small">( Since I am a bit of a hydraulics idiot myself I have a question - do I need to have power beyond? The reason I ask this is because what I was thinking of doing was simply using the hydraulic connections that are already located at the back of my BX23 for the backhoe when it is connected. There are only two connections so my assumption is that these are pressure inlet and pressure outlet (back to tank).)</font>

When those connectors are connected isn't the 3pt disabled? If so then it would put a damper on you using those connectors to work a TNT setup.

 

[jim_wilson]

The BX23 has two quick connects located on the back that the backhoe hydraulics hook up to - I assume that one of them is the pressure feed and the other is the pressure return. When the backhoe unit is removed from the tractor you take the hose that hangs out and plug it into the other QD to form a loop and the 3pt works properly in this configuration. I am not sure if the 3pt works when the backhoe is hooked up to the tractor and plugged in - I never tried playing with it to see if the arms move or not. If I get a chance this weekend I will hook up the backhoe and see what happens. I have the service manual - that might have some insight too.
I guess I need some insight into how hydraulics function - I understand that "power beyond" is high pressure that feeds thru the valve in question to power other hydraulics down the line - I get sort of lost though trying to figure out where the "low pressure return" comes from. Does hydraulic pressure always go down after you push it thru a valve? In other words when the backhoe is hooked up to the back of the BX is the return hose a low pressure hose - and if the backhoe is not hooked up and the loop is connected I get high pressure to power hydraulics down the line - like the 3pt?

 

[aardvark]

The 3pt works when the backhoe is connected. The 3pt hitch operates the mid mower deck linkages, and it also operates when the hoe is attached.

 

[MadReferee]

</font><font color="blue" class="small">( I guess I need some insight into how hydraulics function - I understand that "power beyond" is high pressure that feeds thru the valve in question to power other hydraulics down the line - I get sort of lost though trying to figure out where the "low pressure return" comes from. Does hydraulic pressure always go down after you push it thru a valve? In other words when the backhoe is hooked up to the back of the BX is the return hose a low pressure hose - and if the backhoe is not hooked up and the loop is connected I get high pressure to power hydraulics down the line - like the 3pt? )</font>

A simple explanation:

A low pressure return line is used to carry exhaust fluid from the cylinder that is moving. This line typically goes directly to the tank/sump and not back into the high pressure flow path. It is not good practice to attempt to force this exhaust fluid back into the high pressure flow, thus the need for a power beyond outlet.

A valve with power beyond passes high pressure thru the valve when spools are in neutral and has an additional outlet for the low pressure exhaust from the cylinders.

A valve without power beyond has the low pressure return and the high pressure pass thru tied together in the valve. This setup is used when there is no other valve after this one, meaning the outlet goes directly to the tank.

I am not familiar with the hydraulic circuit for the BX23 which is why I asked the question. Typically the 3pt is the last valve in the circuit. Some configurations have the 3pt disabled, usually with a break in the circuit via a hose being connected or not, whenever the backhoe is connected.

 

[jim_wilson]

I had a chance to get into my tractor storage shed and move the implements around this weekend so I could get to the backhoe. The backhoe is now hooked up to the tractor and the 3pt arms do move when the backhoe is attached. So apparently the 3pt is not disabled when the backhoe is attached. I also dug out the shop manual and found a hydraulics schematic for the tractor - if I can get it scanned in I will post it - it didn't quite make sense to me.

 

[davesisk]

Hi...just a thought here, but you might want to look at selector valves as an alternative. I wanted to add a third hydraulic circuit to my PT to curl/uncurl a front hoe attachment, but the existing joystick valve only had two spools (raise/lower front lift arms, curl/uncurl large bucket). I added a boom and the hoe bucket was on the end of that, so the curl/uncurl large bucket now curled/uncurled the boom arm, if this makes sense. So I needed a third control to curl/uncurl the hoe bucket at the end of the boom (the third hydraulic cylinder). So, I installed a solenoid-operated selector valve between the boom curl circuit and the spool for that circuit. I move the joystick left or right to curl/uncurl the boom, and move the joystick left or right while pressing a thumb button to curl/uncurl the hoe bucket. This might work for you...there's no question about whether a selector valve will work problem free without physics getting in the way! /forums/images/graemlins/cool.gif Hit the URL in my sig...there's a hydraulic schematic showing what I did...pretty simple.

HTH,
Dave