L-Track mounted three panel bed?

I use my T1N chiefly for my business and I have L Track mounted all along both sides in order to secure goods. I am thinking of making a three panel bed system that mounts onto the tracks. My tracks are secured with 5mm sheet screws every 10cm.

Would this be sufficiently strong enough to mount the bed and carry two adults or should I look at an alternative? The tracks themselves are rated at 500kgs but I'm uncertain of the strength of the screws..?

TimmyJ said:

I use my T1N chiefly for my business and I have L Track mounted all along both sides in order to secure goods. I am thinking of making a three panel bed system that mounts onto the tracks. My tracks are secured with 5mm sheet screws every 10cm.

Would this be sufficiently strong enough to mount the bed and carry two adults or should I look at an alternative? The tracks themselves are rated at 500kgs but I'm uncertain of the strength of the screws..?

Click to expand...

You don't mention the number of screws, but you should be fine. Our loft bed is supported by a 2x4's on each side. Those boards are fastened with 6 ea. heavy sheet metal screws. Perhaps #14 size or approximately 1/4" thread. I have carried stacks of plywood and even drywall on that platform without issue.

My cross pieces float so there is little pullout force exerted as the van rumbles and flexes down the highway.

Some detail is here.

https://sprinter-source.com/forums/showthread.php?p=38591#post38591

Have fun. vic

It is easy to transfer most of the bed weight to the floor by using a pair of posts on each side to support the typical L-extrusions that bed panels rest on. Simply bolt the posts to the wall track where convenient. This also is a way to decouple bed height from L-track height.

Posts are very strong, particularly when bolted to a sheet metal wall. Hence can be minimal---maybe 1x3 aluminum or steel rectangular cross sections.

Perhaps bolting in the uprights from a post-and-horizontal-run to the track would be simpler than bolting free-floating horizontal runs in many places. (I'm guessing you'd rather not block L-track access for business use with semipermanent horizontal supports installed.)

Transferring the load to the floor is pretty conservative engineering---nobody seems to have reported walls warping from floating bed panel attachment. But simple if you want the supports removable.

Dan

I have panels sitting on top of 6' 3/4" unistrut that is bolted to 1/2" ply every 2' with 1/4" bolts, the ply goes nearly to the floor (not touching, thus no weight supported by floor) and is bolted to frame with 4 8ga self tapping screws under the window, and 2 1/4-20 screws on the bottom. My panels are wood 2x4 on the 2" axis, with 1/2" ply top; making 2" thick panel.

I don't think I exceed the combined rated sheer strength of the screws, but the rule of thumb for wood span is exceeded; I should be using 2x4 on the 4" axis with an 8" nailing schedule (I use screws, nails are for cavemen).

I sleep two normal size people on the panels without much sagging. Probably 300lbs, 320 with the mattress and bedding. The panels span the width of the van. I have made center posts for each panel, but decided I really don't need them for my application. I have used them when I haul 10+ sheets of drywall on top of the panels.

Deflection of itself isn't an indication of imminent failure on a span that short. Especially if you're only talking about a few people on a bed.

I recall one set-up which used 3/4" plywood spanning the width with no additional supports. It must have had a bit of spring, but strong enough overall. Personally I think that a lighter deck material with cross supports is better weight wise. I was using 3/8" plywood for a deck for a time, but it warped during storage in my garage. The decking is now a re-purposed folding table tennis top that is about 7/16" pressed wood. The built in deck of my folding RV mattress feels to be only 1/4". Even that has worked well for my wife and me and, unfortunately, neither of us is as light as we once were.

Support posts can't hurt, but it would take some tremendous downward force to distort the walls of a Sprinter. Fastener failure would likely occur first. I still recommend designing in some sort of float, or give, in the cross braces to assure that the forces do remain predominantly downward.

vic

A comment on shear strength of fasteners and the number needed for supporting a bed.

The cable backstay on my sailboat is held at the top by a single 3/16" pin. I feel this is a good example because it is easy to see that all the force is concentrated on this one pin.

This is the specs of the cable that is used.

1/8" SS Aircraft Cable

Breaking Strength:1760 lb
Diameter:1/8"
Finish:PlainGrade:304
Material:Stainless Steel
Specification:MIL-DTL-83420M
Strand Core:7 x 19
Type:Aircraft Cable
Work Load Limit:350 lbs.

As an aside, 1/8" galvanized steel aircraft cable has a Breaking Strength of 2000 lb and Working Load of 400 lb. The same size pin is used. Contrary to what some may think, ss is not generally stronger than plain steel. SS resists corrosion and may be harder.
http://machinedesign.com/materials/comparing-stainless-steel-and-other-metals

This is the pin shown relative to the size of a dime.



The pin is not the weak link as to the 1760 lb breaking strength above. I have seen rigging cables break as a result of collisions. The pins used in the cable assemblies are not a typical failure point.


So even if your fasteners aren't equal to the pin design/material in my example, it is easy to see that it won't take too many properly installed fasteners to support a couple people on a bed platform. This example relates to shear strength, not pullout. Pullout is another discussion.

vic

Thanks Aqua Puttana, there is a 5mm screw every 10cm on both sides so I would say that there would be around 20 screws on each side which would be more than sufficient.

I just have to find a way to bolt the bed brackets on the L-track now.. RB Components make a nice fastener but the cost and the shipping to South Africa makes it prohibitive..

I'll update this post when I've found something..

TimmyJ said:

...

I just have to find a way to bolt the bed brackets on the L-track now..
...

I'll update this post when I've found something..

Click to expand...

I've considered that too. I love my L-track, but I've not found receiving brackets like the ones available for E-track. It's too bad because those E-track fittings are nice.



I find that Unistrut offers brackets which I've been able to adapt to many structural uses.



http://www.unistrut.us/index.php?WP=show&GRP=13/16 General Fittings

Those brackets work well with the L-track seat studs, but that doesn't give you snap-in, snap-out ability.



I've also considered using a Unistrut channel open face down over the ring with a bolt/pin at each end as a stud to fit into the snap-in lifting rings.





That would give easy in and out installation, but the rattling might drive you crazy. Some bungee cords wrapped in the correct places or foam rings cut from slip on pipe insulation might stop that.

There's certainly more design considerations than I mention. Just thinking out loud.

vic

The E-track 2 x 4 bracket shown above is one of the reasons for me installing e-track over l-track. If my bed components were stored just feet from van I could install < 5 minutes. My storage location now takes <12 minutes taking my time. I like the look of l-track and the stud attachment is versatile but I solved that problem by having a threaded attachment/mounting point made for E-track. Now I can bolt cabinets, fire extinguisher and tv mount to the e-track without drilling any more holes in the van walls. At the beginning of my conversion if I was going to leave the bed installed full time I would have probably bought the l-track.

Here's a hare brained scheme for you.

How about using the tie down rings with a pipe cut to close to the exact width of the span?



Clip in the one side snap-in ring and insert the pipe into the ring. Next slide the opposite end ring over the pipe, and then attach the snap-in ring to the L-track. The pipe would be hanging in the rings like a sling.

Schedule 40 pipe should be fine. EMT might even work at less weight if you increase the number of cross supports.

The platform could be tied to the pipe at various locations by using 2 holes drilled through the platform with short pieces of line strung and tightened around the pipe.

This fitting may work even better with the pipe idea.



The diagram dimensions are a bit fuzzy, but it appears the pear ring is 1.56" inside diameter. That means that a 3/4" pipe or maybe a 1" EMT conduit will slide into it.

vic

I'm looking at fabricating something like this http://www.rbcomponents.com/components/hardware-1/l-track-fitting-double-threaded-stud-5000.html , I figure if I can have three of these per side bolting the angle-iron bed supports it would work well.. I don't mind having to bolt and unbolt them - my main concern is that when I remove them I'll go back to just having the l-track which is what I need 95% of the time for work..