grapple

[Mith]

Been planning a grapple for the loader now that the forks are underway.
However, I cant say I have had much experience when it comes to grapples.
Anyone car to share thoughts on the geometry of this design?
I'll post pics from the front when I have finished drawing it.
Thanks

Pic shows it both open and closed.

 

[Doc]

Impressive Mith.
No engineering details from me, but I sure look forward to watching this project progress.

 

[joncowcare]

Hi Mith, [we've got to stop meeting like this . . .]
From the design and size of the side-arms [I assume it's to scale ?] I suppose it's going to be used for big bales, round silage bales, etc ?
If that's the case the rams you've got look a bit on the large size, for clamping bales etc, you'll only need inch and half rams to hold them in place and if you put on some back-facing tines for extra grip you'll be fine.
I take it you'll run them off the tractors hydraulics ? No big deal there, the flow will be negligable unless of course you're running some sort of back-hoe at the same time.
I take it you've got any stress points [round the rams] with extra plate welded on ? It's amazing how much power is in a small ram, be quite easy to burst it out.
Good luck and I too will be watching with interest !
Jon

 

[Mith]

Jon, the ram is 40mm bore, its a small grapple. Planning on using it to pick up logs and brush.
The ram is on the large size for the grapple, but its actually cheaper to get a larger ram with 3/8 ports, rather than get a smaller ram with 1/4 ports and use adaptors to make the lines larger. I also am running the hydraulic pressure very low, so I need larger rams that would be used on a normal system.
I haven't really got the design of the rest sorted out, just wanted to know if the opening/closing was enough.
Cheers

 

[joncowcare]

Hi Mith,
So, if it's going to be used for logs and brush you'll have problems with your current design, give me a day or two and I'll post a grab I used with the FC many years ago.
The rams sound fine now you've explained.
Jon

 

[Mith]

Jon, thanks, this is the kind of help I was hoping for.

 

[joncowcare]

Hi Mith,
Hope the enclosed picture shows why this design will cause problems.
Because of the angle of the top arm as the grab closes any logs will be forced out and you'll lose your load.
If you make the top arm rounder that won't happen, I'm doing a design so give me a day or two ok ?!
Jon

 

[Mith]

I hadnt thought about it pushing stuff out, I see what you mean now.
The angled top arm is purely that way because it would be easier to make. I could make a curved top arm, need to make a ring roller, but that is doable.
Thanks.

 

[joncowcare]

Here's the sort of design you might be better with, the shape of actual grabs/tines being like this, about 6-10mm plate will do.
You'll need to put the rams [I assume you'll have 2 ?] further back as a result.
If you need more detail let me know ok ?
I think you know what to do though, so good luck, I'll be watching !

 

[Mith]

I'll probably only use 1 ram. The attachment will only be about 1m wide.

I'll have a play on the drawing program some time with your suggestions and see where I get to and post back.

Thanks

 

[joncowcare]

Hi Mith,
I see what you're after now, yes 1 ram will be enough I'd think.
Sorry for my rubbish drawing, I must admit you're quite a draftsman !
Have you had training or have you got a CAD software programme ?
I tried that Auto-CAD programme and just could'nt use it, bit too complex for me.
Have fun,
Jon

 

[Mith]

My loader is only small (there are pics on this forum somewhere), so the attachments need to be small and light (but not weak....).

Your drawing got the point across thats for sure. I have a qualification in AutoCAD, but not for the program I used to draw the grapple.
Cheers, next rainy day I'll get drawing, shouldnt be too long

 

[Mith]

Ok, how about this one. I cant make a smooth curve easily, but I think this isnt too far removed from what you suggested. The trouble is getting it to work geometry wise, open fully and close fully.
There are a few problems, the ram going below the arm for one, and the overlap between the grapple arm and the bucket forks.

 

[joncowcare]

Grapple

Hi Mith,
That design should be fine but you'll need to bring the ram right back.
I wish I had your skills at drawing, this design is the best I could come up with. Hopefully you'll get the idea ?
If you have your two tines on a movable length of thick MS rod and then have your ram on a bracket so that it moves the tines up or down.
It'll need a fixed point on the base of the grab and then measure it's fullest extension so that at the top of it's stretch the grab is closed.
I'll try and find some way to show it better if it's not clear.
Good luck.
Jon

 

[Mith]

I cant sit the ram behind as you are suggesting because of the quick attach and the single bucket ram. The QA is the black bit that you can see against the back of the bucket in this picture.
I'm stuck with having the ram on the top really.

 

[joncowcare]

How's this ?

Hi Mith,
How's this for a lousy diagram ?! Whatever, does it convey what the frame set-up is ?
It looks like the top of the frame has lugs and the bottom has hydro fixing pins with the whole lot pivoting on the bottom as the ram is in or out ?
There are ways round it, it just depends how competant a welder you are ?
Back soon . . .
Jon

 

[Mith]

Maybe this pic will show how it works. The quaick attach bracket is pinned to the curl ram at the top in the middle, and to the 2 arms at the bottom. The attachments hooks over it, and pins in at the bottom.

 

[Mark777]

Hey Mith....did you happen to see these drawings from a fellow fabricator?

Thought I'd add a little fuel for your mechanical talents to digest

Mark

 

[joncowcare]

Now that looks like a good solution !
Only thing is your limited to the length of logs you can lift, if you retain the bucket but if you use the ram and top grab with your current design it'll work a treat.
I look forwards to the end result !
Jon

 

[Mith]

Mark, I keep a good eye on what Larry and Rob get up to There is alot to be learnt from those 2.