Grapple project OPEN SOURCE

[texasranger556]

Wow that is long. Getting pins that long in and out might get challenging especially if anything gets tweaked.

 

[polemidis]

Wow that is long. Getting pins that long in and out might get challenging especially if anything gets tweaked.

You are right. I will do the simple approach then, with one pin/bolt for each side instead of one big one. Maybe The lid sides are 18" apart.

 

[Drewintoledo]

Polemidis - just curious if you've browsed the patent library for ideas also?

For example, here's the first hit I found when googling: Patent US4285628 - Grapple system - Google Patents

This is a fun exercize. I once created a design for a wind turbine which consisted of winding coils and potting magnets around plasma cut hardened steel hubs and such. Parts included bearings, magnets, copper wire, DIY jigs, bolts, etc. Since I don't own the tools to cut the CRS/HRS, I had a machine shop cut out the parts for me. I created a "kit" that included all of the parts from different suppliers. Before ordering, I placeed a feeler for a group buy out on a forum and had extremely positive feedback. I negotiated with the shop and the various suppliers and was able to reduce the kit price down dramatically. It'd be fun to see something similar evolve here. As others stated shipping ins't easy on the wallet but in my case the project was a financial success.

 

[Zebrafive]

Nothing 19" long though. How about to use rod?

Mine uses a rod. One end has large, thick washer welded on the other is cross drilled for lynch pins. Occasionally I would lose a lynch pin (I think brush would unlatch it) so I bought the HD "black" lynch pins from TSC and have not lost any since.
The tube for the claw is drilled in the middle and has grease fitting.

 

[polemidis]

Got you. I am wondering if it makes the lid more stiff, and if that worths the extra weight. Anyway, I just used the simple approach with bolts/ nuts instead of a tube with a greasable pin. If that fails soon or needs too much greasing I will upgrade it with the enclosed pin.

I think the design is almost complete. I just need some bracing on the lid, some expanded metal at the back and some protection below the cylinder. But I am tired, I need a break from CADing. I will start working on the BoM. What I am missing is a easy way to do the nesting for the CNC. Freecad's nesting tool is in development and does not work well yet.

Here is the step file.
Here are the original Freecad files if someone wants to edit them (needs Freecad v0.17)

With these 2.5" cylinders I get 2130lbs at the closed position
or 1360lbs with the 2" cylinders
And thats the geometry. The cylinder at the closed position is not 100% extended, it has a little travel yet thats why the lids look like they are overlaping the tines.


I love the colors! hahaha


I have no opinion on SAE vs NPTF ports. Other than the SAE uses a o-ring that seals easier, but the NPT has more fittings available??? What are the fittings on the 3rd function of a tractor does anyone know plz?, I found similar cylinders with SAE ports I can replace them

 

[LD1]

Need to gusset the lower tines

 

[texasranger556]

IMO go with SAE/ORB fittings. They seal better and are much nicer to work with especially if you have to take then apart in the future. Generally I like ORB male to JIC male 90 (or 45) degree fittings on cylinders then get female JIC hoses which come with swivels.

There is also ORFS (o-ring face seal) which is about the best for sealing and serviceability, but they aren't as common and more expensive.

Also JIC and ORB use the same thread pitch so in a pinch you can add an o-ring to a JIC male fitting and thread it into an ORB port.

 

[polemidis]

Need to gusset the lower tines

Yes, I forgot it, thank you! But vertical or horizontal? Maybe laminate them to make them thicker too?

IMO go with SAE/ORB fittings. They seal better and are much nicer to work with especially if you have to take then apart in the future. Generally I like ORB male to JIC male 90 (or 45) degree fittings on cylinders then get female JIC hoses which come with swivels.

There is also ORFS (o-ring face seal) which is about the best for sealing and serviceability, but they aren't as common and more expensive.

Also JIC and ORB use the same thread pitch so in a pinch you can add an o-ring to a JIC male fitting and thread it into an ORB port.

Thank you. Is something common usually on the tractor side?

 

[farm boy00]

Yes, I forgot it, thank you! But vertical or horizontal? Maybe laminate them to make them thicker too?


Thank you. Is something common usually on the tractor side?

I think the most common would be npt or sae

 

[polemidis]

Polemidis - just curious if you've browsed the patent library for ideas also?

No, I have never seen that! Thank for the info. Maybe on the next tool, it will save me some time.
Which by the way will be a well rig


Another question came up to my mind. What thickness should the tubings be??

The orange square members are 3"
The purple on the lid is 2".

The blu round tubing on the tines.
The purple on the lids

Do you need me to provide some dimensions/blueprint so you have better understanding without having to download the .step file? Any other suggestions/changes? (gusseting the tines is one noted)
Thank you guys!!!!!!