Bed rack design/build thread - input wanted

I'm starting a small build on my bed rack system. The premise behind the build is to design brackets similar to L2S (not-available any longer) for our Tacoma bed cleats that will accommodate 48"+ cross bar (Yakima style). The reason for 48" bar is that it will allow you to mount the brackets upside down and the rack will essentially hide inside the bed. Longer crossbars 58"+ can be used as well for typical rack look. This will allow for snowboard/bike/storage mounts in the bed of our Tacos using our cleats and easy removal without any permanent modifications.

What do you all think? Would you be interested in this design? Let me know, any input is appreciated before I take this design to my shop.

 

I'd be interested, but it better be a lot more burley than your sketches. Whether its a cargo rack with gear bags of a couple hundred pounds, or a bike rack standing up a couple feet with some 50# monsters, you are going to be putting a lot of forces on these. Make it strong enough and you'll have a market.

 

I would be interested.

 

Its sort of like this

http://www.kbvoodoo.com/shop/toyota-tacoma-bike-mount-system-2005-2015

 

Sub'd

 

Here is the load simulation displacement drawing. 400 lbf was applied to the center of the bar (based on worst case 200 lb maximum weight allowed on each bed cleat). I don't know where it falls on the burly scale but I would call the deformation minimal considering that 800 lb load will show this behavior with two bars.

 

Here is a side profile of the applied stress. As you can see there is very minimal movement on the brackets themselves. This is using 6061 aluminum. Steel can be used for heavier duty applications if there is enough interest.

 

Kbvoodoo is a very nice design. This one is similar to their design with the exception of the round cross bar that is standard for a variety of bike/ski/storage mounts if needed.

 

The brackets are more narrow than the ones nick found. Did you check for shear yielding at the brackets?

 

Joaquin, I attached the stress analysis chart. As you can see 1/4" aluminum holds up quite well.

 

Im not too familiar with metric units, but Im sure you got a handle on mechanics of materials. Cool design too.

 

Fabricate one and I'll gladly guinea pig it for you, powder coated matte black preferred.

 

Is your bed rack attaching to the center of the pole? I would place the attachment points closer to the bed cleats. This should spread the load better. Run your simulations again but put the load closer to the bed cleats below the edge of the bed rack.

 

I'm not a materials engineer, but if I am reading it correctly, you have a single point load in the middle of the cross tube going straight down. I don't doubt that the brackets could hold the weight statically. I doubt that they could handle the forces of a crash, and keep the gear from impaling my skull. Lock the brackets only where the bolts connect to the siderails and calculate the torsional forces on the brackets in a rapid decelleration from 70 MPH or so.

My apologies if I am mistakenly reading your simulation. Good on you for getting that far.

 

Great input Matt, I'll certainly do that next. I'm actually quite curious how that will turn out. First set of brackets will hopefully be made this weekend and off to real world testing after that.

 

Send me a set. I'll test them with the kind of loads that I'm describing.

What modeling software are you using? Solidworks? I have an engineer that works for me, that might be able to help with the simulations.
I'm a plastics guy, but I use a lot of metal for overload and extreme safety factors. PM me if you want to take the conversation offline. I'll respect your IP. Its cool. I think you have a good concept here.

 

Out of curiosity, why do you have the bracket turning up from the side rail? If it turns down, it will reduce the effective height of the load and that may reduce the ??moment of initeria?? (can't recall the name of what I'm thinking of).

Is it to get as much clearance from the bed as possible to maximize the payload?

FWIW, I have a bunch of Yakima components, as well as, a loadwarrior, bike racks, ski racks, kayak J-hooks, kayak saddles, SUP pads, and a rocket box. I can test a bunch of scenarios. I'm fully committed to the Yakima system.

 

Matt, I should be getting samples made after the holidays due to time constraints and will PM you about a set. I use Solidworks for the simulation and you are exactly right I used up-mount illustrations to maximize clearance underneath. Of course mounting under will reduce the polar moment as you said and I can't wait to test it in the real world. I'm afraid I won't get to test the actual design until after the holidays. I have bike, ski racks accessories as well and should be testing this setup on a ski trip in January. I appreciate your help and I'll keep you in the loop. In the meanwhile I'll post some more simulations with lateral forces and loads on the brackets themselves.

 

Sounds great. I've been cleaning out the garage and found an old set of Yakima cross bars which are perfect for cutting to size.