Grable Opinions Needed

[NCMau]

I would recommend the tip of the scarifiers line up where the arrow is in this picture. That would allow you to pick up a small branch or a 2x4.

View attachment 320325

Xfaxman, thanks for the reply but I am not sure exactly sure what you mean by the "lining with the arrows". Are you saying that when fully retracted the the claws tips should be curling inside the bucket or under? For me it is one of the sticky points right now and I am just to digest the options.

 

[Xfaxman]

Xfaxman, thanks for the reply but I am not sure exactly sure what you mean by the "lining with the arrows". Are you saying that when fully retracted the the claws tips should be curling inside the bucket or under? For me it is one of the sticky points right now and I am just to digest the options.

When the grapple cylinder is fully retracted, the claw is up, open all the way. When fully extended, the claw is down, clamping the load.

I mean the claw tips should be where the point of the arrow is in relation to the bucket teeth, so you can pick up small objects. The claw tips do not have to touch anything, movement will stop when the cylinder is fully extended. That is how you determine the cylinder mounting position.

Notice where the tips are on these:

 

[NCMau]

Thanks. That makes sense.

 

[ovrszd]

I don't like the cylinder to be the restricting part of the setup. I welded stops on mine to come against when fully open, just before the cylinders are fully retracted and my claw tips hit the bucket lip just before the cylinders are fully extended. This takes that slamming effect off the cylinders and allows me to exert pressure on the smallest object when trying clamp onto something.

Iused two 2"cylinders and mine opens and shuts very quickly and almost violently. With just one cylinder yours will move twice as fast. I didn't add restrictor fittings to my hoses because I wanted quick movement. But you may have to with just one cylinder to make it easier on the moving parts over time.

 

[Xfaxman]

I don't like the cylinder to be the restricting part of the setup. I welded stops on mine to come against when fully open, just before the cylinders are fully retracted and my claw tips hit the bucket lip just before the cylinders are fully extended. This takes that slamming effect off the cylinders and allows me to exert pressure on the smallest object when trying clamp onto something.

Why? The cylinder physically can handle the pressure. That is why they make "stroke stoppers"


I agree with being able to pick up small objects, but in this project the claw tips will be between the bucket teeth and not touching anything when fully extended.

I used two 2"cylinders and mine opens and shuts very quickly and almost violently. With just one cylinder yours will move twice as fast. I didn't add restrictor fittings to my hoses because I wanted quick movement. But you may have to with just one cylinder to make it easier on the moving parts over time.

It may not be too fast , since he is using a 7 gpm PTO pump.

 

[ovrszd]

Why? The cylinder physically can handle the pressure. That is why they make "stroke stoppers"
View attachment 320791

I agree with being able to pick up small objects, but in this project the claw tips will be between the bucket teeth and not touching anything when fully extended.



It may not be too fast , since he is using a 7 gpm PTO pump.

I have no technically qualified answer as to why. I just think there is no need to put that function on the cylinder when design can do it. I guess if the cylinder can handle it without affect then you are relieving the mechanism hinge points from that stress. In my design the cylinder hinge pins and claw hinge pins are constantly against pressure when fully open and fully closed. Again, I have no technical answer as to which would be better when building.

I agree with you about the speed using a 7 gpm pump. May even find himself waiting on the closure just a little.

 

[Xfaxman]

I have no technically qualified answer as to why. I just think there is no need to put that function on the cylinder when design can do it. I guess if the cylinder can handle it without affect then you are relieving the mechanism hinge points from that stress. In my design the cylinder hinge pins and claw hinge pins are constantly against pressure when fully open and fully closed. Again, I have no technical answer as to which would be better when building.

I agree with you about the speed using a 7 gpm pump. May even find himself waiting on the closure just a little.

Right, that is the key issue in this build of a "light duty grapple". Your build is "heavy duty" and you designed it to handle that stress. :thumbsup: