weightlifting--1401d

[tonyw]

I'm still trying to decide on purchasing a 48" flail mower for my 1401d. The mower weighs 463 lbs. ; the YM169d's(closest US model) 3pt. hitch is rated to lift 661 lbs. I added a load of just over 470 lbs to my 3pt just to see if it would lift. The tractor lifted
the load, but I believe a few pounds more would have been a strain--contrary to the 661 lb. limit listed in the 169 manual.
Is there any reason my 1401d wouldn't lift 661lb.? Would it be too much of strain to use an implement of this weight on a regular basis?
Thanks very much! /forums/images/graemlins/crazy.gif

 

[normde2001]

I think their numbers are based on the weight being centered 2' back of the lift arm pivots, or the back of the lower lift arms. Usually that's where your weight begins and the center point is somewhere to the rear of that, so you are, in effect lifting a heavy weight by one end only. Try it yourself with something you can lift easily if the weight were centered, such as lifting a length of pipe by one end.

 

[tonyw]

Thanks, Norm.
I added most of the weight for my experiment as close as possible to the ends of the lift arms. I used 30 gals of water, myself(169 lbs.),and the weight of the carry-all to figure I had around 470-500 lbs.
I'm hoping 463 lbs. won't be an overload ?

 

[shady1701]

I was wondering if engine rpm would play any role in affecting lift if the hydralic pump is a variable pressure or just a simple gear pump? and what rpm would you need for max. fluid pressure if indeed it is a gear pump rated rpm?

 

[tonyw]

shady1701,
You won't believe it, but I asked myself a similar question over lunch.... I tried my lifting test with the engine at a low idle...why didn't I think to rev it up and see the difference?!

Maybe someone with a little more knowledge about hydraulics will help, please? /forums/images/graemlins/crazy.gif

thanks

 

[MichiganBilly]

Howdy,

Engine RPM definitely plays a role here in relation to your hydraulic pump torque. See formula below:

PUMP TORQUE in Inch Lbs = (HORSEPOWER x 63025) / RPM

Your engine reaches max HP somewhere probably around 2500 RPM if it's diesel. Increased RPM also greatly effects your flow rate in Gallons Per Minute GPM:

FLOW GPM = (RPM x PUMP DISPL.Cu. In./Rev.) / 231

I have no clue what the pump displacement is on your tractor, or mine for that matter. But in general by running some test numbers, you'll see that good torque and max flow will occur at higher RPMs. Torque backs off a little, but that's because the RPMs directly effect the demoninator of the equation. This effect is tempered by the increase in HP though. In the flow equation, the denominator is constant, so higher flow is just a matter of higher RPM. Inertia plays a big role here as well, so good flow is certainly desirable.

Ever notice how wrecker, back-hoe, stump grinder or other big hydraulic equipment operators always crank up the RPMs before going to work? I'd perform your tests at the same RPM your manual suggests for running your 540 PTO.

Good Luck!

BillyBob

 

[normde2001]

I'm certainly no hydraulics expert, but I don't think that is a concern because it's either going to lift the load, lift the front end, or break something. I believe the pressure is in the range of 2200-2400 psi, with a relief valve, I don't have my manual handy. In other words, the hydraulics can easily lift the weight of the tractor, and you are only limited by your balance weight and size of mechanical parts. If you had a backhoe and a loader you could probably lift the tractor off the ground with them.

 

[shady1701]

yap most backhoe drives use the back bucket and front to move around trenches and ditches by picking up and shifting ft by ft pretty neat....

 

[clifst2310]

As any backhoe operator can explain, we usually lift the entire machine on the two outriggers and front bucket before any serious rear bucket work. This is a handy jack in case of tire work /forums/images/graemlins/grin.gif

 

[gatractorman]

MichiganBilly explained it very well and I understand it but for the benefit of some that might not I'll try laymans terms, a properly working hydraulic system with a gear pump will have all the pressure its going to have at idle, whats happening when you increase RPM's is that the pump is pumping more oil making the hydraulics work faster giving you the feeling that it has more power when actually it just has more oil to work with.