Dual action grapple

[IslandTractor]

"There is little if any benefit to dual grapple arms and it would be much simpler, less costly and less weight penalty to just build one 24-30 inch wide grapple arm"... I don't think so Island..I don't have a huge tractor,,and would like to be able to pull my fel up to a rock sitting on the ground,, and have the abillity to nug it into the bucket,,,not have to come down from above and squeeze the daylights out of it trying to pick it up...along with the ability to carry brush out of the woods..
Great Stuff JJ... I'm going to see if I can figure out the geomerty this weekend...

HR3, either you misunderstood my comment or I am not sure you understand how grapples work. I'm not trying to be confrontational I just feel from your statements that you have a false notion of what is involved. Take your example of picking up the rock. It does not involve "sqeezing the daylights" out of anything. One would simply place the grapple over the rock, close the grapple so it cupped the rock and then curl or lift. While the upper grapple arm can be used to crush brush etc it is mostly there simply to hold the load in place. If you are concerned about manuvering a large grapple in confined spaces then you and I share that concern. A narrow grapple, like JJ's, is much more versatile than a wide one. JJ's fabricated grapple would be excellent for getting such a rock as would almost any standard grapple. JJ can get that grapple anyplace he can drive his skidsteer. I can get my 48 inch grapple anywhere I can drive my tractor.

My point was simply that a basic "root" grapple, preferably about 48 inches wide with a single upper arm and weighing in at less than 400lbs about the most efficient type of grapple and best value in terms of bang for the buck. They can be purchased for around $900 delivered. JJ's homemade grapple would fit in this catagory as does my Millonzi and the Markham 48 light duty grapple. My first tractor was a 21hp Kioti CK20 (that is in my avatar) and when I added a QA adapter and a grapple I could still lift substantial loads. See photos below. You really don't need to try to invent a new "mousetrap" to get at rocks, stumps, brush, logs or just about anything else that you can touch with the grapple.

 

[hr3]

Island.. No I don't take it as confrontational at all.. everyones ideas are important,, I see from your pictures that you have nice wide open areas.. I on the other hand live in Maine and my property is very tight..and being a "Maineack" love to build new things that not everybody else has...just because I can... I do understand how a grapple works,,, I'm not trying to reinvent the wheel...just make it work better for me,,

I've finely worked out how it should go together..what do you think...?? just cardboard for now...

 

[IslandTractor]

How do you intend to rig the hydraulics? Will they be two stage or is the first part of the grapple (the part attached to the bucket) stationary?

 

[hr3]

Both half's pivot and there will be 2 pistons run off my front remote,, I plan on a rocker switch to choose between the two to be able to control each one or to float between the 2 in the center position,,,kinda like what someone here is doing with their thumb on a backhoe...

 

[IslandTractor]

I'd just be concerned about the complexity and potential vulnerability of all those joints and the second ram hanging out in space. Grapples do twist to some extent when clamping on asymmetrical loads so take that into consideration. Good luck.

 

[alchemysa]

You dont need something that complicated to pick up big rocks. And for small rocks its usually just easier and faster to get out of the seat and load the bucket by hand.

 

[hr3]

I don't understand what is so complicated about it,,It's no more complicated than the thumb on my backhoe.. I'v been getting off the tractor all my life loading and unloading.. now I would like more seat time,,I'm stopping by the steel shop today to see how much to cut up the pieces..we will see how this all works out,,, It might not work...but now I am more determaned to make ti work,,,

 

[IslandTractor]

I think what we are saying is that you don't need the double action engineering to accomplish your basic mission. A standard grapple would do fine. I know you are concerned about operating in the woods, many of us do that with 48 inch grapples and have no trouble. Unless you are planning on building a 36 inch bucket to go with the dual action grapple you will still be basically limited by the width of your bucket anyway. Your design will get you about an extra six to twelve inches of reach at considerable complexity mechanically and leave you with what might be a relatively delicate piece of equipment compared to a grapple. On the other hand, I admire the resourcefulness and independence you are showing so maybe you will teach us all something new.

 

[J_J]

hr3,

Do you plan to pull the grapple into the bucket or just to the front lip? If you grab a log, and close the grapple, and it touches the lip before it closes on the log, the log will still be loose, whereby, if the tip of the grapple continues into the bucket, it will tighten up on the log, etc.

If you are going to build this, and I believe you can, then the geometry of the Cat-Claw grapple would work. In the open mode, you might need a stop point on the back leg for the grapple to raise correctly.

 

[hr3]

JJ yes the bottom claw will fit eather all the way into the bucket or could be curled under the bucket... when in the bucket there is only a 4" opening so i should be able to grab most anything..

Island.. yes I know you love your grapple... and that extra 6 to 12 inches might come in handy,, I'm thinking the whole thing will only be 2' wide so I might be able to reach between the trees...

 

[IslandTractor]

What? Me? Love grapples? I don't know what you are talking about.

I have an idea for you. Consider rigging a grapple arm to join with a quick spade or set of forks. It would be narrow and have a four or five foot reach. Here is a photo of a quickspade on forks. You'd just need to rig the grapple part to the forks.

 

[J_J]

Here is the idea I am thinking about. The cylinder would push on the front claw and curl down as far as you design. When you open, the claw will open part way and contact the wedge and cause the back arm to raise.

 

[alchemysa]

Island.. No I don't take it as confrontational at all.. everyones ideas are important,, I see from your pictures that you have nice wide open areas.. I on the other hand live in Maine and my property is very tight..and being a "Maineack" love to build new things that not everybody else has...just because I can... I do understand how a grapple works,,, I'm not trying to reinvent the wheel...just make it work better for me,,

I've finely worked out how it should go together..what do you think...?? just cardboard for now...

I hate to keep sounding like a killjoy but this looks like a it could be quite difficult to operate. The double arm design will require good vision, but I presume its attached to a standard bucket so, unless its a huge rock, how are you going to see what you are trying to load into the bucket? And how will you see if the front tooth is coming down above, below, or in line with the bucket edge? Before you start building I suggest you sit in the tractor seat and take some 'line of sight' measurements.

And although this may help you pick rocks out from under trees I can possibly see that a simple job like securely carrying a six inch diameter log with this could be a little tricky.

 

[hr3]

alchemysa,,, It shouldn't be too much of a problem seeing over the bucket,,good point though..I just went out and sat in the seat,,,had the wife put a piece of firewood in front of the bucket,,and about a foot out i could see it... as for the 6" log..the grapple will close down on 2.5" buy the templet that i mocked up...and NO your not a killjoy,,,that is why i'm here asking and taking in all the good infomation...I just wish someone else had done this first to iron out the bugs,,,

Then there is always plan "B"....

 

[Iplayfarmer]

I just wish someone else had done this first to iron out the bugs...

That's why I'm so supportive and excited to see you get working on this. I'm a big fan of pure research. Building stuff purely for the fun and experience of building it is where the great ideas come about, and I'm eager to see where this little journey takes you and all of us watching this thread. Here's hoping all of the bugs are obvious and easy to work out.

 

[Ductape]

I hate to keep sounding like a killjoy but this looks like a it could be quite difficult to operate. The double arm design will require good vision, but I presume its attached to a standard bucket so, unless its a huge rock, how are you going to see what you are trying to load into the bucket?

Bucket / grapple camera?

 

[Berniep]

Here is a quick paint drawing that I made to show the basic idea of something I have been thinking of building to get a bigger bite on loose light material.
Your cardboard cutouts reminded me.
You would only use one cylinder and use a connecting link to actuate the tip of the grapple. The Red spots represent pivot points.
When it is open you can see where it would have a wider opening and as it is closed it would tend to pull in toward the bucket. The link would have to be as strong at the grapple itself because it is exposed to the material being picked up.

 

[IslandTractor]

Man, Rube Goldberg had nothin' on you guys.

 

[hr3]

Not too sure about the camera idea... But Berniep... that is something to think about... I'm dropping of the templates today to be cut out,,I'm thinking 3/8" flat stock.. not sure yet about the pivot points but I'm thinking 1.5" tube stock.. "outside dem.".. ?? What do you think?? I'll do a search for pictures of others to see if this is close...

 

[Berniep]

Not too sure about the camera idea... But Berniep... that is something to think about... I'm dropping of the templates today to be cut out,,I'm thinking 3/8" flat stock.. not sure yet about the pivot points but I'm thinking 1.5" tube stock.. "outside dem.".. ?? What do you think?? I'll do a search for pictures of others to see if this is close...

I would think 1/2 inch unless you are doing a whole bunch of gusseting, Even 1/2 will require some. I don't know about you but I found that I tend to pull a lot on stuff and that really stresses the grapple.