JLwoodworks
Silver Member
Thank you. I modeled it after a couple of commercially available ones. With the exception of my movable hook instead of one permanently welded to the end. I think the tractor will give up before the boom pole does.
SSQA multi use base
- Thread starter Stomper
- Start date
goeduck
Super Star Member
You could set a few trusses with that setup.
Rustyiron
Super Member
Just for ideas, here's one I built about 12 years ago, only because I found a looong cyl. for cheap and had to find a home for it.
Makes a good artificial tree for a rope swing also. :laughing:
Makes a good artificial tree for a rope swing also. :laughing:
Peter 315
Super Member
Just for ideas, here's one I built about 12 years ago, only because I found a looong cyl. for cheap and had to find a home for it.
View attachment 535161
Makes a good artificial tree for a rope swing also. :laughing:
View attachment 535162
That's a redneck swing:thumbsup:
JLwoodworks
Silver Member
Certainly. It's 7 feet long. 1 1/2 x 3 I believe for the pole.
1 1/2 sq tubing for the braces. I'm going from memory of a couple years ago. I can get more definite measurements if you would like.
Jay
I did some figuring today and come to the conclusion that I am going to go with a 2 inch bore x 8 inch stroke cylinder for the grapple on my bucket. This will give me a 36 inch opening when the cylinder is completely retracted. According to the manual my tractors hydraulic system has 2200 psi pressure. This gives me 6908 pound force That the cylinder is putting out. Now that I know the force the cylinder is putting out, How do I figure out what my clamping force is at the end of the bucket. Is there some sort of formula for mechanical advantage for this
Last edited:
wuntun
Bronze Member
- Joined
- Jan 19, 2011
- Messages
- 60
- Location
- Sandhill, Ga.
- Tractor
- JD 4310 JD 790 Allis Chalmers 5030 Husqvarna 2654
Stomper, there is a formula, and the result is a variable graph, but it won't be necessary to do that for approximate force calculations. What your designing is considered a third class lever, with a velocity ratio. For a somewhat accurate force applied after the mechanical disadvantage, use distance from *grapple pivot pin* to the *hyd. cyl. pin* that pushes on the grapple. (let's say 6" for this example) You state to expect 6908# push at that pin, so, at same distance (6") measured from grapple pivot pin toward end of grapple, that force would be the SAME (excluding frictional losses). Now, (assume grapple is 24"), measuring out 6" = 6908#, 12" out = 3454#, 18" out = 1727#, and lastly at 24" at the tip of grapple = 863#. Your definitely not going to be "pinching" stumps in two, or cracking rocks with 863#'s of force, lol, but sure enough will crush old limbs and branches in two if they are caught nearer the middle of grapple at 3454#'s. Think the best analogy (albeit reversed) to lever vs. force is picture torque wrench, one foot long, would take 100# pull on the handle to get 100# torque. Likewise, a TWO foot torque wrench would only need 50# pull on the handle to get the *same* 100# torque on bolt, and so on and on with 3' wrench etc. Torque wrench GAINS power with length, but grapple LOSES power the further away from pivot pin. I have designed and built several hydraulic excavator thumbs, bucket grapples, and dump gate latches over the years. It can be very disappointing to build something without a solid design, only to find your efforts wasted because it is not strong enough, or worst yet, TOO strong and breaks equipment. I commend your undertaking the task to research it fully, you won't regret it!