Trailer Design Student Project (6 Viewers)

[mud4fun]

Hey guys, first post here, so go easy on me. I am a senior at the University of Cincinnati for Mechanical Engineering. For my senior design project, I am designing / building a "drop bed" trailer design. What sparked the idea was the trailer from JLG here: http://www.maintenanceplus.biz/mtcplus123003-4_030.htm

I have been thinking that this is an excellent idea. Especialy when loading heavy objects on dollies by yourself, or low ground clearance equipment. Now, this JLG trailer was the only one like it I found, and the cheapest price I found was $8,000. This is way too expensive for the average utility trailer owner.

For my project, I obviously have to do something different than they did. They use a hydraulic pump system to raise and lower the bed. I will need to go another route here. Any suggestions?

Also for the project I have to do a customer survey. If you don't mind, please click on the below link and take my short survey.
http://www.surveymonkey.com/s.aspx?s...GJxalObQ_3d_3d

http://www.surveymonkey.com/s.aspx?s...GJxalObQ_3d_3d


Thanks guys, I appreciate the help.

 

[davegonz]

Welcome to MUD.

Hydraulics maybe the simplest and most cost effective method of doing this, but other methods do come to mind. Maybe with an electric motor and a rack and pinion type of setup. How about using a couple of electric tongue jacks?

4000# ELECTRIC TONGUE JACK

 

[John E Davies]

This sounds like a great project.

I don't know what sort of hydraulic system that commercial trailer uses (none of the tech pages would work for me), but I would stay with fluid power for several reasons.

Reliable.
Lightweight
Minimal maintenance
Compact components so you can route hoses easily (through the frame rails).
Motor only needs to run for raising bed - the system can free fall to lower.

Any purely mechanical drive system will be more troublesome to maintain. Since most buyers pretty much neglect their trailers (I am not counting folks at this forum!) the system needs to be, above all, easy to maintain.

If I were building one of these drop deck things, I would use high quality industrial or marine hydraulic parts, for example the powerpack and actuators for a boat trim tab system. To learn about superior compact design, take a close look at a powerboat trim system.

If you want to learn about mechanical drives, study the electric driven wing flap or landing gear systems for light aircraft. Maybe your local FBO will let you look at some aircraft in for maintenance. These systems are very compact and lightweight, but rather high maintenance. Just ask any A&P mechanic about "lubing actuators"....

Good luck.

John Davies
Spokane WA

 

[mud4fun]

Survey Update

Thanks John, I will look into that. I do agree that this has to have minimal maitenance and minimal "effort" to adjust.

UPDATAE to the survey... It seems I left off a very important costing question. Please follow this link for a costing "choice" survey. Thanks for the responses!!!

Trailer Costing Survey

 

[tltaylor22]

I've used one of the JLG trailers, they are super nicer and super expensive. I thought about building one with some inexpensive bottle jacks as the hydrolic to move the trailer up and down. I had a solidworks drawing of it and everything, but haven't seen the file for years.

 

[mud4fun]

I've used one of the JLG trailers, they are super nicer and super expensive. I thought about building one with some inexpensive bottle jacks as the hydrolic to move the trailer up and down. I had a solidworks drawing of it and everything, but haven't seen the file for years.

Yes, they are super expensive. Someone on another forum said that they are noisy when towing (track for bed has some play in it...). Maybe it was just the one he had.

I have been looking localy to try to find one to see in person. There has to be a cheaper solution.....

 

[kyot4x4]

those trailer are used by equipment rental companies like United Rentals, RSC Equipment rental, Sunbelt, and Herts equipment Rental. Maybe you could find one to look at there. they were originally made by triple L trailers then JLG bought them out. You could probably use a winch as a bed lifting mechanism. Just some info hope it helps. I work in the rental industry Ill try and find out more info.

 

[roscoFJ73]

For my project, I obviously have to do something different than they did. They use a hydraulic pump system to raise and lower the bed. I will need to go another route here. Any suggestions?

Hi M4F
Ideally,the system would need no power source in the form of hydraulic pumps ,compressors or winches.
One way would be to use the movement of the trailer and the tow vehicle.
You could do this with cranked axles and by locking the hubs and driving a few feet ,the forward movement would raise the bed.
Then you could lock the bed into its travelling position and unlock the hubs.
Lowering the bed would be a reversal of procedure.

But there is always a compromise.In tight areas you mightt not be able to move forward and park the vehicle.
It may only work where there is good traction.

It also depends on the height you want to lift it to

 

[John E Davies]

It may only work where there is good traction.

I thought about a simple system that cammed off the rotation of the tires, but came up with this same conclusion.

Imagine a scenario where you were working heavy equipment like a Bobcat in a dry, sloping field. Unloading would not be a problem, assuming the area was level. Then a heavy rainstorm comes along, turning the ground slick. Will you be able to raise the trailer bed so you can get the rig of the field?

I dunno - I think it's too risky design to be a commercial success, especially with the easy availability of compact and efficient hydraulics.

John Davies
Spokane WA

 

[roscoFJ73]

I thought about a simple system that cammed off the rotation of the tires, but came up with this same conclusion.

Imagine a scenario where you were working heavy equipment like a Bobcat in a dry, sloping field. Unloading would not be a problem, assuming the area was level. Then a heavy rainstorm comes along, turning the ground slick. Will you be able to raise the trailer bed so you can get the rig of the field?

I dunno - I think it's too risky design to be a commercial success, especially with the easy availability of compact and efficient hydraulics.

John Davies
Spokane WA

It may suit a use where it is unloaded/loaded in a suitable place like a barn/warehouse.
No system is 100% perfect,they are all a compromise,such as the $8000 cost for the hydraulic model.
Thats not much to a commecial user ,but private owner may want a cheaper option.
The hydraulic option is hard to beat though
You can load bobcats/excavators onto fixed trailers without ramps you know

 

[Awl_TEQ]

You can load bobcats/excavators onto fixed trailers without ramps you know

Yes you can!!

check this out

YouTube - Bobcat Loads Itself onto Truck

 

[Niner]

My tilt deck 18' car trailer uses a simple floor jack from Harbor freight and has a cradle for it to roll back and forth while jacking. simple yet effective. it was manufactured by Kurts 2001 model.

 

[Brian in Oregon]

You might get some ideas here: Trailers + Trailer Parts | Northern Tool + Equipment

For example, they have torsion suspensions that allow a very low trailer. I don't know what weight capacity you're designing for. These are 2000 lb rated per axle.
Rubber Torsion Axle Suspension Units | Rubber Torsion Axle Suspension Units | Northern Tool + Equipment

 

[mud4fun]

Thanks Brian, those are the exact axles I have been looking at. They are perfect for allowing the bed to drop flush to the ground.