Hydraulic top link

[rasorbackq]

Looking at getting a hydraulic top link.
Is that a good idea to be used with a farmi logging winch.
Yesterday I was winching and my top link broke launching the winch towards the cable direction. My top link was a square tube steel 1/8 -3/16 wall and 1 1/2 x 1 1/2 x 24 long.
The drilled holes were a bit stretched and it just tore the end off when the tree on winch got hung up.

Can a hydraulic top link handle that amount of weight applied to the hoses / cylinder??

 

[ovrszd]

I'm always wary when I see forces put on a cylinder beyond it's hydraulic capability to create.

But then I don't know the capacity of your winch? And I don't know what size cylinder you are considering?

There are several guys on here using Farmi winches. Maybe one of them will see this thread and chime in their experiences.

 

[rasorbackq]

I'm always wary when I see forces put on a cylinder beyond it's hydraulic capability to create.

But then I don't know the capacity of your winch? And I don't know what size cylinder you are considering?

There are several guys on here using Farmi winches. Maybe one of them will see this thread and chime in their experiences.

7000 lb winch and the 2 .5 " cylinder is 21 long with a 10 stroke Think its a 1 .25 rod

 

[ovrszd]

This gets complicated. And I'm totally not the guy that can properly explain it. But here goes.

To determine what your cylinder can stand as far as extending load we need to figure how many square inches of surface there is on the piston surface, rod side of the piston. So we first calculate the surface area of the face of the piston, (pie x radius squared) 3.14 x 1.25" squared = 4.9 square inches. Then we have to subtract the surface of the end of the 1.25" rod. That is 3.14 x .625" squared = 1.23 square inches. This leaves us with 3.67 square inches of surface area on the rod end of the cylinder.

Now we need to determine hydraulic pressure of your tractor? Not sure what it develops, maybe investigate that in the owners manual or "google" it. Let's assume it develops 2000 psi.

We multiply the 3.67" of piston surface on the rod side times 2000 psi = 7,340 lbs of force. So, in theory, assuming 2000psi hydraulic pressure, your cylinder will produce 7,340 lbs of force.

Not sure where the vertical point of the winch spool is in relationship to the lower 3pt arms and the top link fastening point. For example, if it was centered between those two points you would divide your winch pull strength by 2 and end up with 3,500 lbs of pull on the top link cylinder.

You can adjust these unknowns based on your examining the equipment in question. Confused yet?

 

[motownbrowne]

Cool explanation Richard. I didn't know how that worked. Unfortunately, the top pulley of a skidding winch is above the top link. By several inches. So, the force applied to the top link will be magnified, as if by a lever, if my understanding is correct.

Rasorbackq, I think a hydraulic top link is always an improvement over a regular top link, but you may need to go with a larger cylinder. For my tractor which runs my Farmi 351 I'm going to use a 3x12 cylinder. Also, it's possible that your clutch is out of adjustment. Unless your top link was already weakened, the clutch on the winch should slip before breaking a top link.

 

[rasorbackq]

This gets complicated. And I'm totally not the guy that can properly explain it. But here goes.

To determine what your cylinder can stand as far as extending load we need to figure how many square inches of surface there is on the piston surface, rod side of the piston. So we first calculate the surface area of the face of the piston, (pie x radius squared) 3.14 x 1.25" squared = 4.9 square inches. Then we have to subtract the surface of the end of the 1.25" rod. That is 3.14 x .625" squared = 1.23 square inches. This leaves us with 3.67 square inches of surface area on the rod end of the cylinder.

Now we need to determine hydraulic pressure of your tractor? Not sure what it develops, maybe investigate that in the owners manual or "google" it. Let's assume it develops 2000 psi.

We multiply the 3.67" of piston surface on the rod side times 2000 psi = 7,340 lbs of force. So, in theory, assuming 2000psi hydraulic pressure, your cylinder will produce 7,340 lbs of force.

Not sure where the vertical point of the winch spool is in relationship to the lower 3pt arms and the top link fastening point. For example, if it was centered between those two points you would divide your winch pull strength by 2 and end up with 3,500 lbs of pull on the top link cylinder.

You can adjust these unknowns based on your examining the equipment in question. Confused yet?

Yes I was until after i read it a couple times.

 

[rasorbackq]

Rasorbackq, I think a hydraulic top link is always an improvement over a regular top link, but you may need to go with a larger cylinder. For my tractor which runs my Farmi 351 I'm going to use a 3x12 cylinder. Also, it's possible that your clutch is out of adjustment. Unless your top link was already weakened, the clutch on the winch should slip before breaking a top link.

Morning Motown , The winch was slipping but only because my wife can't pull the rope hard enough. I get there and pulled it and it snapped the top link.
Before I got there the top link hole must have bee stressed because the metal that ripped was only 1/4 left. Might just make up a new top link thicker metal and use the Hydraulic top link for other implements.
and

 

[motownbrowne]

Morning Motown , The winch was slipping but only because my wife can't pull the rope hard enough. I get there and pulled it and it snapped the top link.
Before I got there the top link hole must have bee stressed because the metal that ripped was only 1/4 left. Might just make up a new top link thicker metal and use the Hydraulic top link for other implements.
and

10-4, my friend. Just be careful with that thing. There's a thread on here where a guy was using a three point winch and tore the rear end of his tractor right off. Not a cheap repair. When you hitch onto something you can't pull one of a few things will happen: the clutch will slip, the tractor will slide, or something will break, the top link, cable, choker, or tractor. Just make sure you don't make everything so strong that the tractor is the weakest link.

 

[rasorbackq]

I like that idea Motown. Make sure the tractor is not the weakest link.
All of the above did happen . Tractor was pulled until the legs dug in. winch slipped and then the top link broke.
The top link was used for several hundred pulls over 2-3 years and yes both pin holes were oblonged. Will see if I can get a few pics today.

 

[rasorbackq]