Preliminary Grapple Rake Design for 422

[Charlie_Iliff]

<font color="red"> 2,900 pounds of force. Does anyone know the actual breakout force of a 422? </font>
Steve: I'm not sure that a theoretical breakout force gives quite enough information. Essentially, that could be derived from the various lever arms and hydraulic cylinder capability. If the grapple is used as a root rake, however, the procedure would be to wedge the tine(s) under a root, lift the front of the pt, and then lower and maybe bounce the machine while curling the rake. I've seen that process described using the fork attachment, resulting in some bent forks that had to be straightened. I have no suggestion how to put a factor in for the inertia/shock load that can be applied, but I'd be concerned that those of us adept at breaking things may be able to concentrate more than 2900# on a tine. That being said, it may be that occasional bending, or even fracture requiring repair, is preferable to an increase in weight of the assembly.
An aside: Are you using an integrated CAD/engineering package that allows you to do a finite element analysis based on your drawing?

 

[Rip]

The weight you show sounds good at this point... adding in the PT plate and cylinder & hoses, etc should still be in the 300 range. Ten degrees is better than vertical for the QA plate, but if you could space the bottom out a bit to get closer to 25 or 30 you'll like it better. Should be able to keep it plenty strong and no appreciable extra weight.

Be sure to work out all the motion details for mounting the hyd cyl.... measure 5 times and cut once!! Looking Good.

 

[scarg]

We ordered a grapple bucket from PT last week to have a live specimen for review at the factory. I have been on the road for the last week and plan to begin moving forward shortly after the bucket arrives.

Regarding breakout force for root extraction.

If only the outside tines are typically used for this we can make these out of thicker plate.

Steve

 

[Phils]

Can I have the old PT grapple bucket after you have finished looking at it?!?!? I'd gladly give you half of what you paid, less shipping to California! Easy way for you to recoup some of your expenses.

Phil