Single acting cylinder (w/spring) extend and hold position under load

[J_J]

Makes sense.

Ok, how about this then:
Same wiring as above, but use a single acting solenoid valve on the "winch in" side and put a tee between the solenoid and the cylinder. On the 3rd port of the tee, put a N/O hydraulic solenoid (such as HYDRA FORCE 12 VDC N.O. SOLENOID VALVE ) and run that line into the tank line of your power beyond (or directly into the tank).

When you tap Button 1, that activates the electric solenoid valve (turns on a latching relay, the output from the latching relay goes through a N/O pressure switch and into the solenoid). Once the cylinder hits the end of its travel, it builds pressure until it trips the pressure switch (which de-activates the solenoid).

Button 2 runs a N/O SPST relay, the relay feeds the power side of the latching relay for Button 1 (so that you can only start retracting the cable if Button 2 is held down) and the N/O hydraulic solenoid linked to above.

So, when you let go of the deadman switch, it de-activates the winch and opens the valve to "dump" the fluid from the cylinder into the tank (that way even if the "retract" solenoid fails open, you wont pull the cable in).
I can probably draw something up tonight if you want.



Now you have me curious, what tractor comes with 125PSI air onboard (or did you add it?)

Aaron Z

Maybe something like this.

12 Volt Compressor Operating Instructions

They also make pneumatic controlled hyd valves.

 

[bulldogshotgun]

Makes sense.

Ok, how about this then:
Same wiring as above, but use a single acting solenoid valve on the "winch in" side and put a tee between the solenoid and the cylinder. On the 3rd port of the tee, put a N/O hydraulic solenoid (such as HYDRA FORCE 12 VDC N.O. SOLENOID VALVE ) and run that line into the tank line of your power beyond (or directly into the tank).

When you tap Button 1, that activates the electric solenoid valve (turns on a latching relay, the output from the latching relay goes through a N/O pressure switch and into the solenoid). Once the cylinder hits the end of its travel, it builds pressure until it trips the pressure switch (which de-activates the solenoid).

Button 2 runs a N/O SPST relay, the relay feeds the power side of the latching relay for Button 1 (so that you can only start retracting the cable if Button 2 is held down) and the N/O hydraulic solenoid linked to above.

So, when you let go of the deadman switch, it de-activates the winch and opens the valve to "dump" the fluid from the cylinder into the tank (that way even if the "retract" solenoid fails open, you wont pull the cable in).
I can probably draw something up tonight if you want.



Now you have me curious, what tractor comes with 125PSI air onboard (or did you add it?)

Aaron Z

if i was doing it and wanted a deadman i would use a tee and NO valve as aczlan states. but i wouldn't use the latching relay on the second valve just a NC valve, probably with a flow limiting orifice, so that i could feather the clutch in easier. hold button 1 to close dump valve, hold button 2 to start winch, when full speed on cable is reached release button 2. if i needed to feather button 2 to start a load slowly i could.

 

[aczlan]

Here is a drawing of the hydrualic and electrical connections as I see them. Orange is to extend the cylinder and Blue is to allow it to retract. The thick lines are hoses and the thin lines are wires
R1 is a SPST relay that is turned on by Button 1 and it will be held on by R2 as long as R2 is engaged. R1 turns on the solenoid valve to extend the cylinder (as long as Button 2 is being held down). The solenoid will extend the cylinder until the N/C pressure switch opens. At that point, the solenoid will return to neutral and the cylinder will remain extended as long as Button 2 is held down.
R2 is a DPST relay which when engaged keeps R1 engaged and closes the N/O solenoid that vents to the tank
When Button 2 is released, R2 opens. This will open R1 and the N/O solenoid which will vent the base of the cylinder to the tank and allow it to retract.

If you push Button 1 without pushing Button 2, the cylinder should stay retracted as the fluid should go directly into the tank.



Aaron Z

 

[BWSwede]

This is incredible. I really appreciate all the ideas and help. I need to spend time in front of the computer with my friend Google to understand what you guys are suggesting.

Now you have me curious, what tractor comes with 125PSI air onboard (or did you add it?) Aaron Z

Diesel Unimog. They all have an air compressor that runs off the cam.

Set time delay just long enough for full stroke.

I am not sure this would work. The time it takes to complete a stroke varies with my engine speed. Sometimes the engine is at idle when I am working and other times it is at a moderate speed.


I need to carefully read the descriptions of the systems described but from my very basic understanding of what I think I am reading it seems like the controls in a couple of the solutions need to be sequenced in order to properly work. Since I am the guy running the winch, and I know myself pretty well, the controls need to be fool-proof. It is not atypical that when pulling in a hitch the action is like this: pull cable, stop, pull cable, stop, set brake brake, release brake, pull cable, set brake, pull cable, set brake. Rarely ever do I set chokers and then simply pull cable until the logs are up against the tractor.

Aaron, thanks for the diagram. I really appreciate the time it took to design and draw the system. I am going to print it out and dissect it to understand how it works (along with your description of course). Right off the bat though, I do have a question. In this system would I have to press Button 1 each time after I let off Button 2 in order to use Button 2 again?

Thanks again guys for all the suggestions. I really appreciate it.

Blane