loader hydraulics

[heybusdriver]

I am asking for a friend,he has a 8 N with a loader (loader hasn't worked for years). He has it plumbed through the test port, he has no external control handle, he has only the selectrol with the tractor, does he not need a a return route for the hydraulics?
Thanks
Stan
8N179555
8N362039
Vancouver Canada, home of the 2010 winter Olympics
every-one welcome.

 

[JMOR]

No return needed. It is expected to work just like the 3 point lift cylinder, in that the fluid is supplied to the cylinder to lift and then, released to flow back out (return) from the cylinder thru the same pipe to lower the lift. The 3 point lift arms are tied/chained down in this application, so that the flow goes to and from the loader cylinders, via test port, instead of the 3 point cylinder.

 

[JMOR]

A little visual on that fluid flow up/down.
Untitled URL Link

 

[corvetteguy]

My Sauder lift uses the
test port out
and returns through the
test port and another line plumbed into the
top bolt of the plate.

The Lift will not work
WITHOUT THE REAR LIFT ARMS ARE CHAINED DOWN.

 

[TheOldHokie]

(quoted from post at 04:44:22 02/28/08) My Sauder lift uses the
test port out
and returns through the
test port and another line plumbed into the
top bolt of the plate.

The Lift will not work
WITHOUT THE REAR LIFT ARMS ARE CHAINED DOWN.

Ahh - but his will! The two SA cylinders are arranged in parallel with the internal cylinder. As hydraulic pressure output from the pump builds it extends all three cylinders equally until the lift reaches max height and the pump shuts off. Gives him roughly 3X the lifting capacity. This setup is very similar to the way modern Ag tractors are setup - two external cylinders pinned to the rear axle housing.

TOH

 

[souNdguy]

Only caveat being that you may not actually have 3x the lifting capacity, as lift capacity will take into account max pressure and flow pump can produce.. etc.

soundguy

 

[TheOldHokie]

No - the actual multiplier is dependent only on the areas of the rams(assuming a 1:1 mechanical advantage in the linkage). 3X was just a ballpark figure assuming all three rams are of equal area. If the external cylinders are bigger than the internal cylinder the actual multiplier could be well in excess of 3X. Smaller cylinders will produce a smaller multiplier.

Obviously lift time will also go up by the same ratio.

TOH

 

[JMOR]

(quoted from post at 16:46:11 02/28/08)
No - the actual multiplier is dependent only on the areas of the rams(assuming a 1:1 mechanical advantage in the linkage). 3X was just a ballpark figure assuming all three rams are of equal area. If the external cylinders are bigger than the internal cylinder the actual multiplier could be well in excess of 3X. Smaller cylinders will produce a smaller multiplier.

Obviously lift time will also go up by the same ratio.

TOH

Certainly, without all the actual geometry at hand, there is some speculation on my part, BUT having left a hole to slip out of, I would say that the external cylinders dominate, because, the internal cyl is working against about a 3 inch lever onto the lift shaft and coming off the shaft you have about a foot of lift arm, putting that internal cyl at a real disadvantage compared to the external cylinders direct application at the end of lift arms.

 

[TheOldHokie]

(quoted from post at 14:08:22 02/28/08)

(quoted from post at 16:46:11 02/28/08)
No - the actual multiplier is dependent only on the areas of the rams(assuming a 1:1 mechanical advantage in the linkage). 3X was just a ballpark figure assuming all three rams are of equal area. If the external cylinders are bigger than the internal cylinder the actual multiplier could be well in excess of 3X. Smaller cylinders will produce a smaller multiplier.

Obviously lift time will also go up by the same ratio.

TOH

Certainly, without all the actual geometry at hand, there is some speculation on my part, BUT having left a hole to slip out of, I would say that the external cylinders dominate, because, the internal cyl is working against about a 3 inch lever onto the lift shaft and coming off the shaft you have about a foot of lift arm, putting that internal cyl at a real disadvantage compared to the external cylinders direct application at the end of lift arms.

Yes - exactly the reason for my parenthetical slither hole ;-) At one point I toyed with the idea of completely abandoning the internal cylinder in favor of a pair of external ones. May do so yet if I ever get my front pump setup installed.

TOH