North Country
Gold Member
Your linked page doesn't have a drawing that represents the stuck tractor. The above described scenario will get you 2:1 on your pull force.
Stuck tractor - ways to lift?
- Thread starter MNBobcat
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Your linked page doesn't have a drawing that represents the stuck tractor. The above described scenario will get you 2:1 on your pull force.
Mechanical advantage using pulleys with various rigging. The diagram is for lifting, with the hook being the moving load.
"Gun tackle" does not require the top pulley as part of the mechanical advantage. It only reverses the direction of the pull to make it more convenient for lifting.
"Gun tackle" does not require the top pulley as part of the mechanical advantage. It only reverses the direction of the pull to make it more convenient for lifting.
The easiest way to understand the pulley thing is: Disregarding friction, the force in the cable to the tree equals the force in the cable to the tow vehicle, since it is all the same cable. If you look at the single pulley, which has the cable running though it to the tree and tow vehicle on one side, and a single chain to the stuck vehicle on the other, you will see that the force on the chain to the stuck vehicle must be double that to the tow vehicle. A big advantage of this method over a come-a-long or winch is you can use the momentum of your tow vehicle (which should be on dry ground) to really nudge the stuck vehicle along. Just remember that the force is much higher (2x) in the single connection between the stuck vehicle and the pulley. I have broken a few mighty strong looking chains compared to the 1/2" cable that I usually use. Another advantage here is that the tow vehicle can be kept safely out of the line of recoil when and if that chain to the stuck vehicle snaps. The operator of the stuck vehicle is at risk however and I prefer to leave that vehicle unocupied with the transmission in neutral.
tree
pulley ---- stuck vehicle
tow vehicle
tree
pulley ---- stuck vehicle
tow vehicle
This diagram...
...is not really accurate. The principle is there, but the angles of the lines of force decrease the sum of effective force on the load.
The easiest way to understand the pulley thing is: Disregarding friction, the force in the cable to the tree equals the force in the cable to the tow vehicle, since it is all the same cable. If you look at the single pulley, which has the cable running though it to the tree and tow vehicle on one side, and a single chain to the stuck vehicle on the other, you will see that the force on the chain to the stuck vehicle must be double that on the cable to the tow vehicle. A big advantage of this method over a come-a-long or winch is you can use the momentum of your tow vehicle (which should be on dry ground) to really nudge the stuck vehicle along. Just remember that the force is much higher (2x) in the single connection between the stuck vehicle and the pulley. I have broken a few mighty strong looking chains compared to the 1/2" cable that I usually use. Another advantage here is that the tow vehicle can be kept safely out of the line of recoil when and if that chain to the stuck vehicle snaps. The operator of the stuck vehicle is at risk however and I prefer to leave that vehicle unoccupied with the transmission in neutral.
Stargazer
Gold Member
Hi Why not use the skidsteer to dig behind or if only forward the rear wheels then planks brush what not to get out agree use the skid to move mower out of way. again depends on weight of mower/ will skidsteer get stuck. Glad bucket lifted rear enough to get planks in.
pat32rf
Veteran Member
I assume we are talking about a skidsteer on tracks? I've never used one on wheels that had enough clearance or traction to do much....
I've found that it can be a lot easier to chain one timber to the outside of each wheel, like a big paddle, than one accross them both.
When lifting from the rear, never try to lift from the 3pth ARMS. The linkage tends to buckle and that gets REAL expensive....(seen it happen) Dig down to the draw bar if you must lift this way, but even so, most drawbars are not designed to withstand an UPWARDS force....
I prefer a winch and enough pulleys to do the job....
I've found that it can be a lot easier to chain one timber to the outside of each wheel, like a big paddle, than one accross them both.
When lifting from the rear, never try to lift from the 3pth ARMS. The linkage tends to buckle and that gets REAL expensive....(seen it happen) Dig down to the draw bar if you must lift this way, but even so, most drawbars are not designed to withstand an UPWARDS force....
I prefer a winch and enough pulleys to do the job....
TripleR
Super Star Member
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- Mar 5, 2009
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- Missouri
- Tractor
- Kubota M8540HDC, L5740HSTC, BX2200, BX2660, John Deere 425&1025R, Case, Massey Ferguson, Ford
Had it been a John Deere tho it would have bent or broken the axles.
larry
I "think" the height of the big Case helped as it was pulling in an upward angle. that or we were just lucky. Of course Vincent has been doing this sort of thing for 60-70 years too.
I think the time has come to call a WRECKER. A wrecker can hook to the draw bar and the tractor can be pulled from the field. No damage to the tractor, less damage to the field. The area where the tractor is stuck will harden and be like cement when it does dry out. Mother Earth does not like to be churned, driven on, plowed or stirred when wet.
