CA Pipe Frame Loader

Anyone modify the lift cylinders for the CA -8 Pipe Frame Loader to High Volume Low pressure as opposed to the original lift cylinders that were low volume high pressure.  Am looking into a design change and too add a PTO driven hydraulic pump.  

Converting from one hydraulic pressure/volume range to another, seems like it'd involve lots of complicated math, but it is simply a matter of determining displacement.

If the current system is operating at 3gpm and 4000psi with a pair of 1" bore cylinders having 30" stroke, and you switch both to a 2" cylinder, you'll be dealing with

1" cylinder has 0.5" radius... multiply 0.5 * 0.5 * pi (3.1415) = 0.785 square inches of piston area... multiply that by 40" stroke, and you'll have a total displacement for one cylinder of 31.415 cubic inches... divide that by 231 (cubic inches per gallon) and you'll have 0.135 gallons required to make the entire stroke for that cylinder.

Same math on a 2" diameter cylinder, with a 3.14 square inch piston surface, it takes 125.66 cubic inches (just under half a gallon) to extend a 2 x 40 cylinder... so going from a 1" to a 2" cylinder requires about 3x the fluid.

If you've got 3gpm available at 4500psi running the stock cylinders, and you're changing to cylinders that use 3x the fluid, you'll need to go to a pump that has 3x the VOLUME output... so 9gpm... to get the same extension velocity.  You MIGHT need to go up a hose size so that you won't have flow restriction.

Now, as far as pressure is concerned, you'll be going from a 4500psi system down to around 1500psi... there's really no NEED to do the math for this (because you'll have substantially more surface area), but the concept is simple... known pressure against a known surface area results in a calculatable force.

If you have 100 psi acting upon 1 square inch of surface area, you'll have 100 lbs of thrust.

If you have 4500psi acting on 0.785 square inches of surface on the existing system, you'll be seeing 4500 * 0.785 = 3532 pounds of thrust.

If you have 1500psi acting on 125 square inches, you'll see 4710 pounds of force.  Clearly enough, if not excessive, in comparison to the older system.  The best way to solve the situation (prevent breaking something) would be to dial down the pressure relief valve so you're down around 1100psi.  The pump, valve, cylinders, and loader will be happy there.

Now to add the hydraulic curl function, it's just a matter of fabrication, adding a second valve section, and doing some simple math.  If you use the same BORE of cylinder as the mains, your extension/retraction velocity will be same as the main lift rams... but the curl rams will obviously take less time simply because they're shorter.

The only 'gotcha' is that the piston ROD occupies the RETURN side (retract) of the cylinder, and it has much less surface, hence volume, due to the presence of the rod.

Even though you've got some semblance of "live hydraulics" with use of the hand clutch, I'd still go with a crankshaft driven pump like I did on my "B".

A 12V electric pump could also work. They are available in single acting and double acting versions and come with their own resevoir and controls. The ones I have have about a 1 1/2 gallon resevoir. Have not tried it out on the loader, but they pick up the wheel disk and raise my tilt bed trailer (3" piston) just fine. I got mine off Ebay. Easy to install.

Steve's point about getting 'full live' off the front of the crankshaft is a very good one. 

I haven't looked at a CA up close, but if it's same as my '48B, I would probably find a way to put a second pulley-belt on the front of the engine and put the hydraulic pump on one side somewhere.

Using an electric pump seems like a clever idea, but when operating a loader, you'd be operating the pump ALOT, which chews up lots of battery power.  You'd need to come up with a WHOLE LOT MORE charging capacity, and battery... in order to work for any long length of time... and most battery-electric hydropower packs aren't in the 9gpm range... they're more like 2....

The rams... if they're corroded, scrub 'em with some brass wool and see if they clean up... they're probably chrome plated, and if so, might not be as bad as you think.

Hey Guys: Wonderful information you have shared.  Really appreciate all the input.  I can see now why Allis came up with the I 40 and I400, with the deeper/heavier grill section with the pump on the front makes for a real nice setup for the hydraulics.