PT425 Grapple Build Project

[PTRich]

Gosh, one of these days I have to learn to work these computers!!

 

[hazmat]

Moss Road,

You should mount the cylinder pivot above the axis of rotation of the grapple. Then as the cylinder gets longer, the grapple will close & vice versa.

You will have to do some trigonometry to figure out exaclty how far away the pivot should be. Also what length cylinder & the amount of travel that you need so that you are using all the travel & not overextending past your intended stop point.

Unfortunatley I'm a bit busy at work right now, otherwise I'd say send me some dimensions & I'll try to work out a solution for you on ProEnginneer (3d CAD program).

 

[MossRoad]

Thanks! I was watching that thing move and I noticed the same thing. If I attach the bucket end of the lift cylinder in the same axis as where the arms attach to the bucket it won't work. I'll try moving it above the arm rotation axis a few inches. I'll have to experiment once I get the grapple built by using some tubes, one sliding inside the other, to determine the length of travel, mounting locations, etc. Then I'll purchase a clinder to fit.

I saw a grapple on a skidsteer on the way to work today. I wanted to stop and look at it, but had the wife with me and she didn't look like she was in the mood to stop in a bad neighborhood to look at stuff /w3tcompact/icons/laugh.gif

 

[davesisk]

Hey MR, just a thought here, but you might not even need a cylinder to make this work pretty well (although "really well" would probably need a cylinder). You could make the grapple fingers such that they are in a fixed position (or, perhaps, mounted in such a way that you can change their position by pulling some pins, rotating them up or down, and re-inserting the pins). Since the bucket has quite a bit of tilt movement, you could then simply close the bucket against the grapple fingers in their fixed position to pick up branches, etc. Instead of attaching the grapple fingers to the bucket, you'd attach them to the lift arms so they stay in a fixed position and the bucket can close against them.

I don't know if you're looking for slick and fancy, or simple and cheap. If simple and cheap is what you're after, the fixed approach might suffice. Anyway, just a thought...

Regards,
Dave

 

[davesisk]

MR, now ya got me thinking about this for my old tractor! I'm seeing a few heavy duty pitch-forks (or something very similar) as a key component (at least for mine). Cut off the handle, and weld 2-4 of these onto a section of angle stock or square tubing, then weld or bolt a plate onto each side that can be attached to the two lift arms, with pins to set the pivot angle so that the bucket just about closes against them. Hmmm...

Dave

 

[Sedgewood]

I too have been thinking a grapple bucket would be the cat's meow. I picked up an old cultivator for this kind of project a month or so ago. It has half circle "teeth" with about a 24 inch dia, mounted on a shaft that happens to be the length of the bucket width. I think I can mount the shaft just above the top lip of the bucket and the teeth will curve round and just touch the front lip of the bucket when closed.

 

[bubenberg]

mr. m.r. here i found a drawing of a grappler very similar to the pt designe:http://www.jrbco.com/products/specs/wla_spec/sp_gb.html.
hope that will help?!?!?!?!?

good luck

hrl

 

[bubenberg]

here is another one with two independent sides as i whis the pt one would be. http://www.rankineqco.com/products/ati/gb4ctl.html

 

[Sedgewood]

<font color=red>I think I can mount the shaft just above the top lip of the bucket and the teeth will curve round and just touch the front lip of the bucket when closed.</font color=red>

Here's a picture. I have 5 of the cultivator tines to mount on the shaft but will probably use 4. The two cylinder split shaft idea sounds really good but I'll probably forego that at least for now. Also there's a fitting that goes on the square shaft to add a lever arm to attach a cylinder to. Now to find a block of time....

 

[MossRoad]

Like a "fixed" thumb on a backhoe. Sounds like it might work. I want a hydraulic ram to open mine a little more and I also want to use it as a first experiment with hydraulics.