HYDRAULIC CHAIN SAW

J_J · Mar 16, 2006

Has anyone ever used a hydraulic chain saw with the PT?. The chain saw is a closed loop system. I am thinking that a closed loop system uses a variable displacement pump. What would happen if I locked the trigger down and used the aux hyd for the supply. which is a gear pump and always pumping. Aux lever up for cutting, and back to neutral for stop. I could probably get this saw about 20 to 30 ft in the air for trimming.

Spiffy · Mar 16, 2006

I saw a skidsteer attachment mfg advertising one a while back and was drooling until I saw the price! Since you have the saw, and we all know about your fab skills, you're set. /forums/images/graemlins/cool.gif

I always thought open/closed loop only referred to the valve [trigger]; closed requires a variable pump, but I don't think affects the motor. If you are wiring the trigger ON it shouldn't matter. The motor type won't matter either, but [you've probably already ran the figures] you might want to double check the motor's volume/rev and figure it against your flow rate to make sure you don't over rev it.

edit <font color="red"> I'm thinking "Closed Center"; perhaps "closed loop" is referring to something different </font>

pajoube · Mar 16, 2006

I have been looking for something like that for a long time. Also have need for a hydrulic hedge trimmer and I would be all set.
PJ

Spiffy · Mar 16, 2006

How about this one? Tele Saw

I don't remember the price; just that it was expensive.

J_J · Mar 17, 2006

I should have said closed center, which stops the fluid at the valve. I am not sure of how much it takes to run the hyd motor, so I will start with the aux circuit. Small hyd notors usually run very fast. If that doesn't run fast enough, I will go with the PTO circuit. My PTO circuit has a lever to control speed. The chain saw is a Fairmont.

MossRoad · Mar 17, 2006

The thought of cutting that far overhead scares me. I see plenty of potential for dropping branches onto myself. /forums/images/graemlins/tongue.gif

pajoube · Mar 17, 2006

My main needs are for a hydraulic hedge trimmer. That way I can use my manlift with the forks and trim the hedges.
PJ

J_J · Mar 17, 2006

I have never seen a hyd hedge trimmer. but I have used my Echo 4 ft hedge trimmer while standing on the ROPS. Those 2 stroke hedge trimmers come in different lengths, The long ones will give your arms a good workout. I finally found my hyd pole pruner, but I am not sure what type valve it takes, open center or closed center. The only writing visible is 3.8 gpm at 2000 psi. Any of you guys ever worked a bucket truck, and used the hyd system?

Gravy · Mar 17, 2006

JJ,

I'm just learning about hydraulic valves, but if I'm not mistaken (and I very well may be), the distinction between open and closed center is really only of importance to the hydraulic pressure supply side, not to the implement. AFAIK, the implement only cares whether the work ports are blocked (as for a double acting cylinder)or drain to the tank(as for a motor) in neutral.

Gravy

Spiffy · Mar 17, 2006

You bring up an interesting point Gravy. The auxillary lever on my PT [and I presume all of them] is a cylinder spool (which won't shock the motor if slowly returned to center instead of letting it snap back)

The electric PTO valve actually just blocks a "dump" line, so the system behaves more like a motor spool (although with a little residual pressure).

Anyway, JJ if you're planning to wire the trigger open on it like you were the chainsaw, it shouldn't matter. For a wild guess, I'd say your auxillary port @ half throttle might keep the flow around the rated mark; the reliefs might be a little higher than that 2ksi, but I wouldn't sweat too much unless it's near priceless to you.