I'm working on a new product idea, and I need what might be considered Jolly Green Giant size (and strength) rubber bands--although they are almost certainly not called rubber bands. These would be about 12-15" in length when stretched, and would exert perhaps 30-50 pounds of force. (Think of these as the rubber bands the Jolly Green Giant's orthodontist probably uses.) These should be able to tolerate pretty temperatures down to -10 deg. F. Any suggestions?
UPDATE: There are what are called "pallet bands" but those are even a bit larger than what I need. This company, Aero Rubber, seems to make stuff in about the right size range. I will probably have to call them and see how much force the 9" x 1/4" bands generate when stretched to 14".
Alternatively: something with a lot of elastic force and hooks at both ends--like a bungee cord, but perhaps more durable and with smaller hooks. It might even be a bungee cord, but perhaps one intended for an extreme environment application, such as the stainless steel hook variant for marine use. But contracted, it probably needs to be 8" or less, so that it produces sufficient force at 14". McMaster-Carr stocks an 8" bungee cord (with some pretty impressive hook options) that has a maximum stretch of 14". I'm not sure what the force exerted at 14" is, but these seem to be standard size of other bungee cords, and Hooke's Law would probably apply roughly the same for all these bungee cords that are made of essentially the same material.
Check out aircraft landing system bungees. Older, small aircraft like the Piper Cub used these as the shock absorbers between the main (front) landing gear....
ReplyDeleteOn the off chance there's still a rubber band or bungee manufacturer left in the United States, you should give them a call and tell them what you need.
ReplyDeleteThey might have an old die lying around that, when combined with the right material choice, will give you what you need.
If they don't have to retool and you might buy a few thousand, it could work.
For prototypes you could just gang up large elastic bands on clamps until you get what you need.
If I remember correctly, when you place springs in series the math is the same as circuit resistance in parrallel, and when springs are parrallel, the math is the same as circuit resistance in series.
(Forgive me if I've stated things you already know)
Have you considered the black rubber tarp straps used by OTR truckers? They come in various sizes. We found them very useful aboard our sail boat. The 10" size will stretch to 14" with substantial holding force.
ReplyDeletehttp://www.etarp.com/accessories/98-1-0n.html
Very useful suggestions! The rubber tarp straps--do you know what the force the 10" size exerts when fully stretched?
ReplyDeleteI haven't done the math on the tarp straps but they are very cheap at most any hardware or truck stop. A trial and error experiment could very well fulfill your needs.
ReplyDeleteAny suggestion where I might find these tarp straps locally? A trucking supply firm? Or would a hardware store have them?
ReplyDeletehttp://www.mcmaster.com/#tarp-straps/=a0u0cz
ReplyDeleteI can order them from McMaster-Carr, but I was hoping to find some tomorrow on my way home. Ace Hardware shows them online, so perhaps the Ace Hardware in Eagle will have them in stock.
ReplyDeleteI've just used inner-tubes from an appropriate tire size, chopped with the paper-guillotine when the secretaries are off on lunch break.
ReplyDelete