Need some design help

[Gary_in_Indiana]

Harv, my very first thought on this was very similar to your U-bolt idea. I was going to use a single piece of 1/2"-5/8" plate slightly wider than the frame rails to accomodate two U-bolts on either rail. The length of the sides under the rails would be such as to accomodate one U-bolt at the rear on the angles section of the frame rail and another forward enough to be on the flat. The front side of the plate would be cut 90 degrees from the sides. The back, however, would come to a point so the plate took on the appearance of home plate. At the back point would go my trailer ball (or receiver). In the middle of the (home) plate would be a loop, hook or eye-bolt.

The driver could toss this on the ground, place a bar with an attached ratchet across the frame rails, run the ratchet strap to the center of the plate and crank it up. Then the U-bolts could be attached without having to hold and balance the plate. When that's done just unhook the ratchet strap and toss it and the pipe in the trunk, put the dolly on the ball, load your car and go.

Why didn't I go with this plan? Well, to get the U-bolts far enough forward to get the front U-bolts on the flat part of the frame rail moved it dangerously close to the tandem air bags and, even without that problem, I wasn't sure if the tension on the two U-bolts on the flat of the frame rails would be sufficient to keep the assembly from sliding back.

I know U-bolts are all that hold cargo boxes, etc., on straight trucks but also know they have the downforce of the box working for them, too.

 

[shade2u2]

Gary,
This beyond what you're looking for, but a guy has picked up trucks from us before with a "hydraulic-trailer/hitch/connector contraption" that he had custom made in Indiana - I think... Basically, he pulled in with his pick up towing this heavy-duty "trailer" full of hydraulic thingies.
He hooked up one end of the trailer to the 5th wheel of one truck. Then he tilted the trailer & drove his pick up on the trailer. He then jacked up the other end and hooked it up to the other trucks 5th wheel. He then jacked up the trailer further against the trailer axle so that the 2nd truck's drive tires were off the ground -> ready to be towed...
It was all pretty slick.
My detailed, sophisticated, diagram /w3tcompact/icons/laugh.gif /w3tcompact/icons/laugh.gif may (or may not) help to visualize...

 

[hazmat]

Gary,

If you go for the swinging tongue, you would only have to pull one pin, and then rotate the tongue. No need to assemble/disassemble the fifth wheel tongue.

If you go with a car trailer instead of the dolley, you can beef up the tongue as much as you see fit, IE build it more like a frame, than a single tube.

 

[hazmat]

Here is the beginning of a the "framed tongue"

You could add diagonal bracing and additional members as needed.

I would put a flat plate on the bottom of the rotating post to give it a bearing surface you could grease to make the rotating easy.

I think the trailer would give you better "tongue weight" on the fifth wheel, I don't know how much it takes to keep the things together. You won't have to worry about overloading the big truck.

 

[Gary_in_Indiana]

Shade,

I actually have a car trailer that works very much like that. It has an electric hydraulic tilt bed. I tilt it down, load one on the bed. So far it's the same deal.

Whereas you describe the second semi being lifted by it's fifthe wheel, I then drive one axle of my second vehicle being transported onto a platform on the rear of the trailer and secure the wheels on that axle to that platform. I then lower the bed which lifts the one end of the second vehicle and off I go with one carried on the trailer and another towed (dolly'ed?) behind it.

That concept would be slick even for the semis IF I were typically buying more than one at a time at the same place (or even reasonably on the same route). /w3tcompact/icons/smile.gif

 

[hazmat]

Gary,

Option 3. Custom built "car trailer" that attaches to semi truck fifth wheel. Custom semi truck fifth wheel in bed of pickup truck chase vehicle.

Unhitch from pickup, back the semi under, load and go!

 

[Gary_in_Indiana]

I definitely like the idea of the swinging (or at least reversable) fifth wheel tongue extension. I assume I should still be using tubing and not pipe for each of those pieces for strength, right?

The only other thing I'd want to add would be a similar connection in the horizontal piece so the length of it could be adjusted for varying distances between the fifth wheel and the rear of the frame rails and so that when the dolly isn't being used as a fifth wheel option the tongue extension could be removed in smaller, lighter sections.

Would it be reasonable to attach a tube sleeve atop the vertical piece (making it something between a 'T' and an 'inverted L') through which the horizontal piece could be moved then pinned?

 

[Gary_in_Indiana]

Stephen,

Option three (already suggested by one of the guys here who's been campaigning for a company four door dually 4x4) changes the concerns from "fabricating and framing" to "funding" this plan. /w3tcompact/icons/smile.gif

 

[Anonymous Poster]

Gary, since yer havin so much fun with the CAD program, here's option Q.1.2
Tubular member from 5th wheel to double channel (similar to meat rail hanger) across frame rails at tail end of truck. {may have to sit foreward to accomodate beavertail rails, so this cross member would slide on tube like Reese}.
Drop leg from tubular assembly to 18" ball height for dolly.
Cross member could be U bolted to frame rails.
Make in 3 pieces, and pin together so it could ride in chase car trunk, and easily assemble by driver.
Blue piece (5th-rear could be telescopic to accomodate different 5th locations) Red piece (teletoung assembly to ball dropleg, inserts into teletoung) Green piece Cross member with sleeve for teletoung)
[censored], this is almost as much fun as Christmas assembly directions.

 

[Gary_in_Indiana]

Was there an attachment that was supposed to go with this showing all the colors you described?

Actually, it sounds like kind of a hybrid of the two styles. the fifth wheel connection provides the actual connection point to the truck and the cross member eliminates lateral movement and the pivot at the fifth wheel. It sounds like a workable plan. /w3tcompact/icons/smile.gif