open stacker project

[davidbrady]

Hi Greg,

Good to hear from you. Glad all is well.

I think it's feasible. Just a couple of points:

1) Depending upon the trailer weight, width, and axle track width you may want to consider outriggers. You have a loaded upside down pendulum and you need to watch eccentricities. Ideally you'd be loading and unloading on a perfectly flat and level surface but that's never going to happen in the real world. You have suspension deflection, side support arm deflection, bearing free play at the rotating pins, and all the other environmental concerns from soft soil to wind to tire air pressure to contend with. If the pendulum articulates outside the normal plane you can have some fairly large bending moment forces on the booms and on the pins. There's considerable weight up there with the two Razors plus the supporting platform and tracks. I can see a several thousand ft-lb bending moment to contend with. This can all be much better controlled if you have outriggers to shore up the trailer platform.

2) The bending moment will always be there so you have to deal with it. You'll need a pivoting system at the trailer that spreads the forces across the trailer longitudinal beams. Something like a third trailer axle. Imagine another axle that lies across the frame longitudinals and u-bolted into place. Alternatively a subframe can be constructed to span the width of the trailer longitudinals. This way we've eliminated the twisting forces that you'd see be simply connecting the rotating pin to one frame member - now it's a force couple spread over two frame rails.

3) Once the pendulum is fully loaded and rotated into it's final resting place I'd like to see it firmly pinned to the trailer frame rails. My preferred point of attachment is up at the tongue by the steer wheels of the leading razor. This makes a secure attachment point pinned to the trailer in double shear without any intervening links; likewise, when you're loading I'd like to see it pinned back by the dovetail, and

4) I'd use hydraulics. The winch system is simple but I want better control. With the winch there's always the possibility of cable slack, and I know the pendulum is just waiting for any screwup to make fools of us. I'd put the hydraulic rams between the two trailer axles with the piston attached to the highest apex where the two triangles meet.

Just my opinion, hope this helps.