Grapple cylinder placement

[MrZukerman]

Just built a grapple to bolt to the top of my bucket but not sure how to determine were to mount the cylinder as far as angles and distances from the pivot points of the arms, any help would be appreciated.

 

[welderboy14]

Just built a grapple to bolt to the top of my bucket but not sure how to determine were to mount the cylinder as far as angles and distances from the pivot points of the arms, any help would be appreciated.

do you have a picture?

 

[Scotty370]

Mr"Z" I can't tell you the placement, but, I can share the way Willl and I arrived at it for the Willl Da Beast. You have to sketch up your cylinder, closed and open. I used Sketch-Up. Don't believe any of these measurements! This is for conceptual use only! I will say, the placement is critical! I'd advise card-board mock-ups, before the welding sparks fly! ~Scotty

 

[3RRL]

Scotty has shown the two most important positions.
The first is when the grapple is fully closed against your bucket lip or toothbar. That's when the cylinder is fully extended.
-Pick a point above the grapple jaws which represent your cylinder attachment (pivot) on the grapple jaws.
-Draw a radius using your fully extended cylinder dimension from the center of that point.
-See where that arc goes when it goes above your top bucket lip.
-You can then pick a spot on that arc (above your bucket top lip) that will be the position of the bucket pivot.

The second is when the cylinder is fully retracted. After you've picked those two pivots, see where that first pivot (the one on the grapple jaws) ends up with the clinder fully retracted.
-You can do that by drawing a radius from that bucket top lip pivot using the fully retracted cylinder dimension.
-Rotate the grapple jaws up until the grapple jaw pivot intersects that radius.
-That's where the jaw will be (fully open) when the cylinder is fully retracted.

You may have to repeat the first two steps if you don't like where your grapple ends up when the cylinder is fully retracted. You may need to pick another first pivot spot on the grapple jaws to get a desirable condition when the grapple is fully opened. Here is an example of the bucket grapple I designed for my buddies. They wanted as much opening as possible. So I had to move the first (and consequently the second) pivot point until I got what I wanted.
Hope that helps and is not confusing.
Rob-

 

[GE222]

In a case like this, I will most often seek out what has already been designed, and go from there. Most often, someone has already found out how NOT to build something. Also keep in mind, that mass production has found the cheapest way to design something which may not always be the best.

Nice reply, 3RRL!

 

[3RRL]

Thank you.
One thing I forgot to add when picking the location of the pivots.
Make them tall enough off the grapple jaws so that when the grapple is fully closed against the bucket lip, the cylinder rod does not hit the cross tube stabilizers. In my drawings (all side views) you can see the little squares on the jaws. Those represent cross tubes that run from one jaw to the other to give the grapple strength from tweaking. I have 2 drawn on the jaws. I later added a thin plate to protect the cylinder rod from rocks.
Here is what the grapple looks like with that protector plate.
Rob-

 

[radman1]

3RRL

I always love seeing your completed DIY projects. Way over the top and beautifully machined. Nice job on a "simple" grapple.

 

[p38]

3RRL,
Very nice looking Grapple. Do you happen to have a drawing or materials list you would be willing to share?

Thanks,

g

p38@fcs.net

 

[3RRL]

Thanks guys, but I don't want to deviate from MrZuckerman's thread nor steal it.
Please send me a PM and I will gladly help you out with what I've learned. I am at a different computer but will be on my personal one in a couple days. Again, just trying to help the OP with placement and some tips regarding that. The original thread on the grapple build was done by my wife, Loretta. You can go here to read about it:
My Very Own Grapples
Rob-

 

[PineRidge]

Mine isn't as pretty as 3RRLs (that really looks nice Rob! do you use that thing ) But I can tell you that if I had mounted mine the same way my bucket would now be "toast"

If you build a grapple you NEED to be sure that you reinforce the top of the bucket to withstand the hydraulic forces that will be put to the top of the bucket by the grapple cylinder.

I know a guy who put one on a New Holland and a day later he was cussing and straightening his bucket.

Anyway maybe you can get a few ideas from the grapple that I added to our New Holland. It has worked well for our needs. Our Grapple

Good luck with your build

 

[Knight]

I figured out by taking two plastic pipes. One fit inside the other.
I had the stroke marked on the pipe. I slide the pipe back and forth until I found out my stroke and my locations. Crude, but worked.

 

[countrybumpkin]

I figured out by taking two plastic pipes. One fit inside the other.
I had the stroke marked on the pipe. I slide the pipe back and forth until I found out my stroke and my locations. Crude, but worked.

A very good yet simple metiod.