open stacker project

[RainbowrvGreg]

Here is a link to a project I am working on. right now I have a bit of a problem with the side Mirror fit on the pickup so I may need to use my other suv which has an issue with length. the video is on a rented server I use to host how to video's for my website customers and project proposals for landscapes. Please give me input on my plan. Thanks in advance

https://screencast-o-matic.com/watch/cFfefeDmlF

[mbulriss]

Greg,

Love it. Love the simplicity of design with the triangles.

By way of background, I have a Chapparal Aluminum bed trailer with dove tail, large storage box up front, dual tire racks above and wing walls on the sides. I also have a Performax 24’ enclosed with 5’ tongue and 1’ hitch puts me at 30’ behind the 43’ Bird. I mention these because my random comments below will refer to features of them. I really wish I had an enclosed stacker now!

-If drawn to scale, your balance looks pretty good.
-Love the rotating triangle design. Simple & effective. Your single point of failure is the rotating or hinge assembly. As such, the support for that assembly needs to be quite robust. I have some ideas we can discuss. Call me if you want. Remember the pics I sent of my rooftop crane assembly?
-Per you comments, I would not even try to rotate the loaded assembly by hand, nor would I use hydraulics. The stackers tend to use winches. Mount a heavy one on the tongue and let it do the work. Power source from bus plug is readily available. And it’s a safety if something breaks and has to be loaded manually.
-the fancy “arches” can be light framed aluminum sheet attached to the triangles. Just like my wing walls on the Chapparal.
-if you can dove tail that trailer bed far enough that might solve some rear clearance problems and maybe reduce overall load height which is a large problem as you mentioned.
-Highly endorse your rear load ramp and structural support idea. The back door ramp and dove tail on the enclosed trailer is great.
-Suggest drop in wheel chocks on the back of the upper ramp. Kind of like motorcycle chocks. Drop them in a hole in the ramp and insert a lock pin on the bottom side of the stud.
-Good thing that trailer has 7k axles! I assume it’s pretty stoutly cross framed underneath. How close will you be to the 14k limit when fully loaded? Most stackers have triple axles for added safety.
-Does that trailer require 2&5/16” ball and have you upgraded your receiver to 2.5” for 20k+ loads? My LXi has been converted to 2.5” receiver and braced (builder said he wouldn’t blink at 30k load but that’s not happening). On the other hand, an enclosed stacker might approach 20k and I like the safety factor. Loaded with the Hummer, the enclosed trailer pulls as easy as the Chapparal.
-Do you have equal lift load bars and anti sway bar hitch assembly?
-I have to assume that trailer has four wheel brakes!
-Trailer tires rated for the 7k axles?

There may be others I forgot, but that’s my random thoughts for now. You got what you paid for!?

Neat idea. Fully loaded height will make checking your routes ahead of time fairly important.

FWIW.

[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.

[Arcticdude]

I know this is a totally different approach, but with all the work going into the cantilever setup, why not just make the trailer longer, stack the 2 Razors across the front, one on top of the other and then put the truck behind to help balance the tongue weight? That way, if your tow vehicle changes, you've got essentially an open platform to put it in. You'd eliminate all the cantilevering issues, make it easy to enclose the Razors for better protection and be able to load or unload each as an individual item. You only want the top Razor? No problem, unload only it. You would also lower your CG and not have to have any hydraulics or winches unless you just want something as a back up solution. Any ramps needed for the Razors would simply slide in under the truck. It doesn't look like you'd be adding that much to the overall length.

[davidbrady]

Greg,

If you take the axle idea for the pivot point and you make it a drive axle with a differential, then you can rig up a driveshaft, a gear reduction transmission, and a hand crank - no hydraulics, no winch, no electric motors or power source other than you manually spinning a crank. Simple, reliable, and fun.

[RainbowrvGreg]

I am trying to keep the weight off the trailer build. the hand crank sees like a good idea. Semi trailer Landing gear is also an idea. I use them on my equipment trailer with an 18,000 lb excavator sitting between the landing gear and the axles. they sell for 50.00 a set at the salvage yards

Arcticdude the rzr are too long @9 foot. The stack would also be too high, I stacked the trailer with quads and a simple farm jack lift prior. but I now need to race with a full roll cage, no more quads for me. was thinking of a way to load the two rzr's on the short bed truck

[davidbrady]

Greg,

It'd also be fun to play around with shock absorbers mounted on either side of the pivot bolted between the frame and the diagonals. With the correct shock you may be able to crank it just past center and then take your hand off the crank and let gravity pull it down gently onto bump stops. The shocks will limit velocity and also provide safety against a dangerous free fall.

[davidbrady]

Greg,

I don't want to steal all the fun design work away, but if you indulge me for a moment. In the interest of weight savings, the hand crank gear reduction transmission can all be done with chains and sprockets. For example, if the differential is around 4:1 and the worse case torque on the rotating cam is 5000 ft-lbs (just one Razor loaded, so no counterbalance) then a 100:1 gear reduction will bring the force needed on a 2 ft long crank arm down to 25 lbs, and at 100:1 it'll only take 25 cranks to travel the 45 deg or so of full motion. We already have 4:1 at the differential so now we need an additional 25:1. We can use two 5:1 stages. This requires one intermediate shaft. From the crank to the intermediate shaft we'll get 5:1, and from the intermediate shaft to the differential we'll get another 5:1. The first stage chain will have a max tension of around 250 lbs so all of the first stage can be done with bicycle components including a bicycle lower bracket for the crank pivot. In fact, an extended pedal crank arm of a bicycle can be used for the hand crank. The second stage will have a max chain tension of 1250 lbs so a motorcycle chain and sprocket assemblies might be more appropriate. If you want you can include a full bicycle lower bracket assembly with pedals and crank arms and you can crank it with your feet like riding a bike! All of this can be very cheap, compact, and light' plus when you want to get a workout in you can use it as a stationary bicycle! LOL!

Give me a lever long enough and I can move the world...

[RainbowrvGreg]

Thanks for the input. Sorry been away for a while
Power: I first wanted to do hydraulic power and may still go that way to put even force on both sides. The landing gear style jacks with built in reduction gear two speeds are also a option but I am not sure how they handle other direction force .....as with truck camper jacks and semi trailer jacks the load force is one direction. Q? is how will they act bi directional. and there will be a need for two people and active coordination between two people which is not a reliable mechanical action. semi jacks run in pairs have a drive line between them which cause additional design constraints.
Pivot. I think I understand Davids info on twist. two areas of twist are the trailer bed and the platform relative to the triangle sides. I can use an adle as the pivot but then the top deck will not be attached to the suspension so I will need to start out on a level surface and if there is a twist issue, address it with cables or rigid support guides.
Shock Freefall: learned a lesson with this one when I built a single axle pivoting trailer for my towcar. talk about design rebuild.

---

Arcticdude thanks for the input. I did stack the last couple of toys sideways but the rzrs are too long for this. they are lite enough to rid on top of the truck but when I add the rack weight things once again get too heavy . this same trailer had the quad rack prior here is an image of that stack. (sorry cant find one of it loaded this image was taken after I slid in a new radiator via bumper access). the quads entered from the other side of the trailer where I cut the trailer top truss off and installed two 3x3 tubes to hold this top rack up. the pivot of the rack was on top of this side of the trailers top truss tube. the power was a farm jack on the other side. The twist David talked about was non existing because the 3x3 tubes welded vertical held control. there might some use for using a support to work realtime to control the twist with that setup.

[Arcticdude]

I hadn't realized those RZR's were 9' long when I suggested putting them crossways. That does pretty well rule that out, for sure. Even trying to stack them in lengthwise front of the Hummer makes for a long trailer and probably not a viable option for your usage. Nothing is ever easy, is it!