sheet foam shock absorber

im making a trailer for a longboard (skateboard) with a speaker setup on it weighing around 20kg, the speaker im using for it is a fairly durable plastic mobile DJ style speaker but even so i'll be pulling it around over potentially rough tarmac/asphalt surfaces on a trailer made from skateboard parts so could a couple of small sections of foam sheet sandwiched between skateboard truck baseplates and the deck offer adequate shock absorption? i have squishy 1.5cm thick yoga mat foam or firmer 1cm thick sound proofing foam to choose from...

sort by: active | newest | oldest
Downunder35m4 months ago

Try rubber mounts for vibrating machine parts ;)
You know simple stuff like these for example:

http://www.tcbroschoppers.com/media/catalog/produc...

Gives you a sturdy mount on the board while keeping shocks and vibrations low.
Available in many different sizes, lengths and with harder or softer rubber.
If you have any indstrial supply stores around you can check them and get a feel for the rubber before buying.

After looking at some of you "insane" guys on Youtube I think you need something better.
Hoping you have good imagination I go without pics as I am really bad at hand drawings.
Instead of a board mount your (skateboard) trailer axles onto an open frame.
In each corner of said frame you mount strong springs, like those on discarded trampolines.
The springs hold the plate for your equippment.
Tricky part is getting it right in size for your needs and to find strong springs that are short enough.
But this way the tiny surface area where the springs hold the plate will eliminate all high pitched vibrations, the springs must be under enough tension to slightly expand.
Like that the spring takes out lower pitched vibrations and small bumps.
Mount the equippment with soft dampeners as liked above and you should be fine.

ambientvoid (author)  Downunder35m4 months ago

thanks, those are some interesting ideas to think about. i'm curious what videos you were looking at that puts me in the 'insane' category? :D

also while googling trampoline springs and trailer suspension i came across suspension caster wheels, all the ones i've found so far are for industrial type loads far heavier than my setup but the design looks simple enough that i'm wondering if i could duplicate some with one of those soft rubber bushings in place of the heavy duty spring...

Can't find the link anymore was listed on the side when checking other Youtube videos.
The guy was going downhill a 4km long stretch of road, overtaking cars, "undertaking" trucks and powersliding through both lanes to reduce the speed a bit.
Thank god I have never done such dangerous things during my skating years...
Oh, wait, we did not have cameras to record our stunts, maybe that's why noone noticed ROFL

Did you consider the off-road version at one stage at least?
I mean those wider axles that allow you to put air filled tyres on them?
Might even work with normal axles if the frame is made to fit and you misuse some wheels from an old pram.
I used these pram wheels (with metal rims) for my kite buggies.
The tyres don't seem to do anything good for your back until you are dumb enough to try solid wheels one day ;)

ambientvoid (author)  Downunder35m4 months ago

i considered pneumatic tyres at first but after experimenting with attempting to skate my mountain board down the road i decided that hard wheels with some kind of shock absorption would roll better, tyres are great if you have a bike with gears but way too tiring if not.

i found this article about spring loaded caster weight limits where they talk about entry level spring casters supporting a maximum load of 75 pounds but there isn't any mention of minimum load for the spring to compress, at a guess (i need to find some scales) the weight of my trailer would be between 45 and 55 pounds so over a rough road surface at say 8 to 10mph would you say that load would be enough to compress the springs on a pair of casters and have them absorb the shock?

ambientvoid (author)  ambientvoid4 months ago

http://www.douglasequipment.com/casters-1/what-are-the-weight-limits-for-spring-loaded-caster-wheels/