Grapple fixed grapple for bucket?

[hz293]

I know that there are fixed thumbs for backhoes. Has anyone seen info on one that would work for a tractor bucket or one that uses other than hydraulics? What was used for this function before hydraulic grapples became popular? Is there more than one way to do this? I did a search but couldn't find anything.

Harris

 

[schmism]

its the same setup as a hydrolic grapple.. but instead of all the hoses, diverter, cylinder, just put a toplink type bar in were the cylinder would go.

add the hydrolics as $$ allowed.

 

[IslandTractor]

I like Schism's idea. You'd have to measure to see what size toplink so that you could have the grapple in a mid closed position so by curling the bucket you'd get decent compression of your load. It would limit you to a certain size load (not bigger not smaller) but would be better than no grapple at all.

 

[3RRL]

When you think about it, this principle is the same as using a diverter valve to operate the grapple except in reverse. After positioning the bucket, the curl function is disconnected and the grapple works down to the stationary bucket. On this method, the bucket curls up to a stationary grapple jaw. Only difference you'd have to turnbuckle the jaws to position them in this case, whereas you can position the bucket curl hydraulically which is much easier...and switch back and forth of course. That's why I like the true third function solenoid diverter valve where you can move grapple and bucket simultaneously.

 

[hz293]

I love it. Just ask on TBN and you shall recieve.

Harris

 

[DJLX]

What a minute here-if it is the same as a standard grapple with a fixed toplink or turnbuckel replacing the cylinder then the bucket and grapple/ thumb would never come in contact with each other since the grapple is mounted to the top of the bucket. The grapple/thumb would have to be tied to the loader arms somehow so the grapple/thumb and bucket would be closed in the full curl position. Unless I don't understand, I don't see how having a bucket and grapple/thumb that doesn't come together would be worth anything.

 

[bucmeister]

Bingo, in order for it to work as a stationary grapple then it will have to be mounted to the arm of the loader not the bucket assembly which is where a hydraulic grapple would go. You are essentially trying to pinch the load with the bucket just like on an excavator does with a thumb on the dipper arm.

At least that is my $0.02 worth.

 

[bcarwell]

I like this idea. I have a Kubota 7500 compact with FEL and can't yet justify all the hydraulics, etc. Yet I have piles of cedar limbs/brush I need to move. Pushing it or even FEL forks won't cut it. I'd like to be able to grasp a pile with the bucket up against a thumb of some sort. Why don't they make them ?

Could somebody provide a very simple sketch of what one of these things would look like and how it would attach or describe it a little better ? I'm having trouble visualizing what one might look like, where the toplink would go, etc.

Bob

 

[bucmeister]

In thinking about how to do this the thought occurred to put the thumb below the bucket almost like a rigid rake then uncurl (dump) the bucket to hold the load against the rake. Just the reverse of the way we usually think to use it. Otherwise the mechanism would have to stick out over the top of the bucket like the horns on a Triceritops dinosaur.

 

[IslandTractor]

Maybe we need Rube Goldberg to figure this out. Or perhaps just consign the idea to the round file of half baked bad ideas. To do it (and I am not sure it would be practical with all loaders) you'd have to rig a way to attach either a long toplink or just a thick dowel or 2x4 from the distal grapple arm to the FEL torque tube so it was fixed. As I imagine it the grapple base itself would still be fixed to the bucket as usual. That would need to be the fixed point on the FEL to which the grapple arm would be fixed so when you curled the bucket the load would be trapped by the grapple. Obviously there are some potential problems you could cause if you didn't think through how to distribute the load on the torque tube. Maybe I am missing something obvious but it seems possible so long as you can 1) get the base of the fixed "top link" attached to the torque tube safely and 2) work out the right length of "top link" or thick dowel so the grapple arm is held in a roughly half open position that allows the bucket to curl against it.

What I invision would be useful for carrying light brush, I would not want to use it as agressively as a properly mounted grapple. And I imagine it would work better with the smaller FELs where you are not going to be putting something like 4000lbs of curl pressure on the grapple to be transmitted directly to the torque tube. You really would need to be careful to distribute any force being placed on the torque tube, perhaps by clamping a 4x4 as a mounting base all the way across the torque tube or something like that. It also might make sense to try just a long 2 inch dowel as the "top link" so if something has to break it would be the sacrificial element rather than the torque tube.

I would imagine that bucket geometry would be important too. All buckets rotate back when curled so that would move the base of the grapple and I guess would tend to force the grapple closed given the fixed base and fixed "top link". Not sure about that.

I don't have a fancy drawing program or any drawing ability but I used my mouse to sketch out what I mean in the attached jpg. Again, this would take some experimenting to see if it could work.

I would imagine someone really clever could build a scissoring grapple device that opened and closed just by curling the bucket. I may have actually seen something like that described here once upon a time.