Tree Puller for hard to get at trees

[Wall Road]

Any ideas about keeping the chain from riding up on the tree trunk?

 

[radioman]

you need to wrap the chain around the tree once and then the second wrap goes under the first row. Sometimes with a small tree that has bark stripping and sap oozing acting like oil, you need to wrap the chain around a few times. It's MUCH easier to use a choker chain instead of a regular chain. The choker chain has a large hook that allows the chain to slip to tighten up like a noose.

 

[CWL]

I like to use a chain that has a clevis on one end instead of a hook. That allows the chain to cinch down really tight.

 

[MikeD74T]

Any ideas about keeping the chain from riding up on the tree trunk?

Get a 6" piece of 2" pipe. Weld a 3 link piece of chain on the outside. Put the pulling chain thru the pipe, around the tree, & hook to the third link of the short chain. When pulling chain tightens the noose the end of the pipe bites into the tree & won't slip. MikeD74T

 

[alltoys]

MikeD that should work better or just as good a tree grubber!!!

 

[jcaron2]

hi, just adding another visual aid to this awesome idea. Good Luck and be safe.

Rhett

Being the geek that I am, I did the exact calculation. The mechanical advantage is actually

F2/F1 = sin a/sin b,

where a is the angle between the post and the ground (75.5 degrees in Rhett's drawing of an 8' post leaned over 2' against the tree), and b is the angle between the post and the chain down to the tree (14.5 degrees in Rhett's drawing). This formula assumes that you're pulling in a perfectly horizontal direction (i.e. your tractor hitch is as high as the top of the post, or you're pulling with a really long chain so that it's essentially parallel to the ground).

Note that it's not the length of the post per se, but rather the angles that determine the mechanical advantage. (Just like with a normal lever the mechanical advantage isn't dependent on the absolute lenght of the lever, but rather on the ratio of the lengths on either side of the fulcrum). However, for a given distance from the base of the tree, a longer post will give you a steeper angle and therefore more mechanical advantage. And more importantly a longer post means that the mechanical advantage is maintained longer (i.e. you can pull the chain a lot further before the post tips over).

For what it's worth, as the angle b gets really, really small, Rhett's simplified formula gets closer and closer to being exact. In his example, the actual mechanical advantage is 3.873:1, which is within about 3% of his back-of-the-envelope calculation of 4:1. If the post was 10x closer to the tree, the angle b would be 1.43 degrees, and the mechanical advantage would be 39.987:1, which is within 0.03% of the 40:1 ratio his formula would predict.

 

[Treemonkey1000]

Being the geek that I am, I did the exact calculation. The mechanical advantage is actually

F2/F1 = sin a/sin b,

where a is the angle between the post and the ground (75.5 degrees in Rhett's drawing of an 8' post leaned over 2' against the tree), and b is the angle between the post and the chain down to the tree (14.5 degrees in Rhett's drawing). This formula assumes that you're pulling in a perfectly horizontal direction (i.e. your tractor hitch is as high as the top of the post, or you're pulling with a really long chain so that it's essentially parallel to the ground).

Note that it's not the length of the post per se, but rather the angles that determine the mechanical advantage. (Just like with a normal lever the mechanical advantage isn't dependent on the absolute lenght of the lever, but rather on the ratio of the lengths on either side of the fulcrum). However, for a given distance from the base of the tree, a longer post will give you a steeper angle and therefore more mechanical advantage. And more importantly a longer post means that the mechanical advantage is maintained longer (i.e. you can pull the chain a lot further before the post tips over).

For what it's worth, as the angle b gets really, really small, Rhett's simplified formula gets closer and closer to being exact. In his example, the actual mechanical advantage is 3.873:1, which is within about 3% of his back-of-the-envelope calculation of 4:1. If the post was 10x closer to the tree, the angle b would be 1.43 degrees, and the mechanical advantage would be 39.987:1, which is within 0.03% of the 40:1 ratio his formula would predict.

OUCH OUCH OUCH Math my brain is going to explode! Actually I am kidding. Thanks for the explanation.. I have used leverage techniques for pulling fence post and stuff before..

 

[WH401]

Another option for attaching to the tree is to use steel cable, wrapped around the tree a time or two. That's what I've used with my puller and it grips very well.

 

[GE222]

jcaron2,
Nice job with the calcs, being an engineer, I agree. With that in mind, the person using this method must absolutely take into consideration the added mechanical advantage on the cable or chain used from the top of the pole to the tree trunk. I would strongly recommend using a chain as they typically wont whip around as a cable does when it breaks.

 

[WH401]

jcaron2,
Nice job with the calcs, being an engineer, I agree. With that in mind, the person using this method must absolutely take into consideration the added mechanical advantage on the cable or chain used from the top of the pole to the tree trunk. I would strongly recommend using a chain as they typically wont whip around as a cable does when it breaks.

If this is directed towards me, I meant a short piece of steel cable with loops in the end that can be hooked to a chain. Using a steel cable by itself wouldn't work because you have no anchoring point for the puller to stay in place on the cable, unlike with the links on a chain. And as you said, not to mention whip-lash effect that a cable can give if it breaks.