Steering logic.

[Spiffy]

You're putting in a larger pump? Awesome!! /forums/images/graemlins/cool.gif I have to hear how that works out.

I have to wonder (though on the 2445, I don't see room) if you'd have room to run a separate pump for steering; now that'd be really sweet.

 

[J_J]

The pump that I have for steering and lift, is a very small pump. It's about 4x4 in , and driven by a belt on the front of the gas engine. The larger pump will go through a flow divider , and should give the action that I want.

 

[BobRip]

Sorry JJ, I did not mean to offend. The larger pump should do the trick. I will say no more.

Bob Rip

 

[toy]

JJ yeaterday while I was using my pt I remembered this post so I tried turning the steering to lock and as I already knew the lift and tilt stoped moved it back and it picked up again. Moved the steering back to lock and turned loose of the steering wheel to see if it would pick back up just by turning loose of the steering wheel and it never picked back up the tilt, turned the steering wheel back a little and the lift and tilt picked back up again. While I was doing this with the steering wheel locked I could hear the hissing sound of a bypass but instead of it coming from the releive valve in the back it sounded like it was coming from the steeering valve[motor] . I beleive that valve has a bypass port in it when it has reached its max to keep it form building up undue pressure in the steering system. You mentioned that your pump ran off of a fan belt to the motor. Is there enough room for you to add a seperate pump just for the lift and tilt and of course withe its own releive valve. If there is that would be nice, in my 425 I think there is some unused ports on the oil tank if Im not mistaken. If you could do that you would still have the power beyond on the steering circuit to supply oil for another seperate auxillary valve since you wouldn't be using that part of the circuit for lift and tilt any more. I got a message when I started to send this message stating the rules for the forum I hope I haven't offended anyone I hope it was something that was sent to alll users. But if that is not the case and someone is offended at my posts I am sorry and I didn't mean to offend.

 

[J_J]

Thanks for the info. No, I don't have room for another pump, but I have seen pumps with 2 or 3 sections on them.

I think every one is getting that message about rules. Number 8 was in bold print.

 

[MossRoad]

TO: All users of the PT forums...

As to the rules appearing at the start of every post... that has been added to all users of TBN just as a reminder for those that have never taken the time to read them. No one in the PT forum has anything to worry about(except me). This is one of the cleanest, best mannered, best intentioned group of people I've ever dealt with. I'm probably the black sheep here as far as following the rules go and appreciate being kept in line via PM once in a while. /forums/images/graemlins/wink.gif Thanks to all for contributing to many people's enjoyment of this forum and TBN, overall.

J_J... As to multi-section pumps, our PT425 has three pumps. One in front of the engine for drive, and two behind the engine. One is piggybacked onto the next. Not sure if that is actually a multi-section pump or just two pumps running off the same shaft. They have seperate intakes, so I guess that makes them seperate pumps?

 

[J_J]

On two of my pumps, the variable speed pump for the wheel motors, and the PTO pump, which is a fixed displacement pump are bolted together, and run at the same speed. They are two different pumps. The third pump is the lift and steering pump. The multistage pump is like the pump in the attachment. They could all be the same or have different displacements. You see these a lot on golf course machines that use hydraulic gang mowers.

 

[MossRoad]

I found an old post of mine that explained the pumps pretty well. Here's a link to it. There are a couple of pictures of my pumps there, too.

 

[J_J]

This is a picture of my lift and steering pump.

 

[ol'George]

You fellers talk of tamping a fence post,
don't think I ever did that, I dig a hole by what ever means available, auger or shovel, then drop in the post, add a 5 gallon pail of water give er take, then kick in the previously removed dirt, wiggle the post some to distribute the dirt maybe poke a branch or stick in there to make a good sloppy mess and walk away.
Tomorrow it will be as hard as if yall used cement. been doing it that way for 50+ years.

 

[ponytug]

Most of us don't have soil like that...

You fellers talk of tamping a fence post,
don't think I ever did that, I dig a hole by what ever means available, auger or shovel, then drop in the post, add a 5 gallon pail of water give er take, then kick in the previously removed dirt, wiggle the post some to distribute the dirt maybe poke a branch or stick in there to make a good sloppy mess and walk away.
Tomorrow it will be as hard as if yall used cement. been doing it that way for 50+ years.

 

[MossRoad]

You fellers talk of tamping a fence post,
don't think I ever did that, I dig a hole by what ever means available, auger or shovel, then drop in the post, add a 5 gallon pail of water give er take, then kick in the previously removed dirt, wiggle the post some to distribute the dirt maybe poke a branch or stick in there to make a good sloppy mess and walk away.
Tomorrow it will be as hard as if yall used cement. been doing it that way for 50+ years.

I see this is your first post. Welcome to TBN!

 

[ol'George]

Thank you!!
I thought I would try to give back a little after all the "taking" of knowlege I have done here on TBN.

 

[J_J]

ol'George ,

On the subject of post. Maybe you are young or old, but whatever the case, old people don't like to physically work more than they have to, and therefore, when there is an easier way of doing things, they will. I don't particular like to dig holes, but have dug a few in the past. Of course you can dig or auger a hole, but the post pounder, and the vibratory units will sink them in short time. If setting post is your business, time is money, and whatever will do it the fastest is the way to go. No backfilling, no nothing, just go to the next one. Although they are expensive, they will pay off in the long run

 

[ol'George]

posts.--
well lets just say I'm old enough for social security Ha,LOL
and I've sunk a few holes
I have a 12" Hyd. auger I built to put on my hoe, in place of the bucket.
in normal ground, it takes longer to position it, then does to screw a hole in the ground, I timed it once, 4 seconds, now that was in clay, not rock
if I want to just drive in steel posts, I use the fel bucket to push them in,
or the hoe bucket, but when I'm sinking utility poles, I use the auger. then do the water trick.
In my younger days I didn't have power equipment,
I had more time than money & I did everything by hand.
but now it is just a hobby keeping me busy so the devil don't take me.

 

[ol'George]

I'm not trying to hyjack your discussion & I'm not familar with your machines at all, but thinking
does the steering circuit have a fixed priority valve for the steering with relief,
and the excess go to the lift, if so
I'm just wondering maybe a high hour machine might have excess by pass on the spool in the priority valve giving some lost gpm's to tank?.---
or the priority orfice is allowing more Gpm's than needed to the steering circuit and the steering relief is dumping those Gpm's it to tank when turning the gear to lock, starving the lift circuit.
forgive me if I mis understand the lengthy discussion. just trying to learn
are you using a ross steering valve?(pump they call it) .

 

[J_J]

Yes, the steering does have a priority valve. Only the fluid from the steering cylinders goes back to tank. When you are not steering, or steering slightly, the rest of the fluid flows through the steering valve and on to the lift and tilt valve, and then back to tank. So even if the steering was bypassing, the fluid would go downstream. If the priority valve was not working, the cylinders would creep. The steering and lift on my PT-1445, is powered by a .194 cu in pump, providing 1.5 - 3 GPM, driven off the fan belt. This gives me the ability to lift about 1200 lbs.

A hard turn either way, will use just about all the fluid and the lift and tilt will barely move. So sometimes you have to coordinate total steering verses something you are trying to lift or tilt.

That pump is just one of three that the PT uses.

 

[ol'George]

ok, that is what I was thinking. they been doing it that way for many years
I looked up a pix your unit so I now know what you have.
I'm thinking the other pumps are for the hydro units??
just the rambling of an old man, but that pump is on the small side, to do both jobs together, as you have found.
I'm sure you have it in your mind what you want to do by now, if anything.
If it were me I would entertain the idea of going a bit larger on the pump,-- or divorce the steering, adding a separate dedicated pump, possibly of the auto industry design.
They are a dime a dozen & easy to obtain @ salvage
they put out #900-1400 .
Although I don't know what is required for your articulating cyl's I'm assuming you have 1,-- or 2 in a cross over design, either way they require about the same flow. unless I forgot something.
the other side of the coin is you already have lotsa pumps in there!!
---trying to think like a liability scared safety engineer, they don't want the operator turning and lifting @ the same time.
Geo.

 

[ol'George]

Moving along so as to keep the posts small.
I understood a priority valve to split the flow into 2 distinct flows:
One metered either through fixed or adjustable orifice,
the other is excess flow. to do other work or dumped--RTT

so the steering valve gets for example, a dedicated 1 gpm.
( we understand there is a relief valve in that circuit with RTT on excess pressure rise)
it is directed through the steering valve to do work (turn cyl's) or it is RTT.

The excess flow goes to a spool valve to do other work,-- in this example tilt & lift
if the pumps output is 3 gpm's, 2 gpm's are left to do this other work.
( again just for example)

If the priority valve is leaking somewhere it will not cause any cyl's to creep as they are down stream from the tilt/raise spools ( and usually they have load check valves)
Disclaimer:
I'm not always right and by discussion I learn.

 

[J_J]

My PT's pumps are sized for the HP available. I could go a little larger on the lift pump, but not much. The pump size is also related to the safe operation of the machine, meaning that although the lift cylinders have more potential, is does no good if the back end comes off the ground. Actually larger cylinders will increase the lifting power, but again, there is a lift weight ratio that has to be considered.