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NOT... HDT related


spindrift

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I thought it would be best to go to the "collective" and seek input. I've tried to find a solution but coming up short. I have three, separate electronic cabinets which are transported to various locations in three, separate wooded crates. The cabinets enclose some fairly sensitive equipment so my utmost concern is the preservation of component integrity. Here is a picture of the caster wheel on one of the cabinets:

 

http://i1250.photobucket.com/albums/hh530/excursionps/Simulator%20cabinet%20caster_zpsk1fxgior.jpg

 

And here is a pic of the base of one of the wooden crates which houses the cabinet:

 

http://i1250.photobucket.com/albums/hh530/excursionps/Simulator%20crate%20base_zps2zhtabpk.jpg

 

I'm trying to isolate the vibration during road travel as much as possible. I thought maybe there was some kind of a caster that had vibration isolation built into the caster. The weight of the cabinets, including the wooden crates are 650#, 750# and 825# respectively. The questions are: isolation on the cabinets or on the crates? Once the cabinets are loaded into the crates, accessibility is limited to only two of the four casters.

 

Thoughts...recommendations? Thank you.

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Just a wild idea. I saw some self made air bags that used 12" water discharge hose, sealed on the ends and then had a tire valve stem installed to be used for leveling RVs, but could be used for all sorts of things. Would an air cushion, perhaps 2, installed after the crate is strapped into its travel location, provide enough isolation from vibration.

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Most of the crates we have sensitive equipment sent to us uses either closed cell foam, or the donuts that Jeff shows for isolation, along with lag bolts to the skid floor. How often does the equipment get crated/un-crated? With a semi-regular shipping schedule, rpsinc waterhose could help speed things up.

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Their are casters available with coil spring suspension. Snap On tools used them on tool boxes for a while. I've also seen palletized crates with an inner floor that was mounted in rubber iso-mounts like used on generator sets, the equipment was secured to the inner floor and the outer crate was then closed for shipping. Also available are shock sensitive labels/stickers that visibly indicate if a given G force has been exceeded so you can tell if something has been mishandled.

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Thanks for all of the replies. I've been skeptical of using something that is spring mounted as I've been told that springs don't absorb, or dampen, the energy created when a transport vehicle runs a rough patch of road.

 

The crates will be transported at least once a month so the method of isolation needs to be convenient. And since you can't get to two of the four casters on the cabinet once they' re loaded into the crates, I'm assuming that whatever method is chosen, it would be a modification/addition to the crate itself.

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You could try mounting a Mason Industries vibration pad or mount between the caster and the crate. They may be able to recommend something base on the weights and the space available. If in the Vancouver Area, we used a company called Vibra Sonic that used the Mason mounts and pads for a project that had specific noise isolation requirements.

 

Dave

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Well...I just received a quote for 12 spring loaded casters; $4,300. I had no idea these things are so expensive. Does anyone have a reputable supplier of this type caster? I'm now thinking that I should have the spring loaded casters on the individual cabinets and some kind of vibration isolation mounted inside the wood crates and under the cabinets.

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Message berzmo, he should be able to design and maybe build you casters.

I'm thinking more like a mini shock set up on them like on your air ride seat, or I just bought a set for a mountain bike that I'm going to use on my grandsons hotrod wagon.

Some of the shocks have adjustable damping.

Would be very easy to design and build.

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Well...I just received a quote for 12 spring loaded casters; $4,300. I had no idea these things are so expensive. Does anyone have a reputable supplier of this type caster? I'm now thinking that I should have the spring loaded casters on the individual cabinets and some kind of vibration isolation mounted inside the wood crates and under the cabinets.

Just kidding......but at $4,300 clams Henry could sell you a ET jr hitch to just mount the crates on...........

 

Long time ago I had a distant relative that drove a Nitro truck all over back roads from a remote plant in the middle of Nowhere N. Dakota to the West Texas oil fields and never drove through any towns of any size..........but as I recall the Nitro vile was suspended inside of a large tank with a jelly of some sort to dampen the road bumps............

 

He did retire with a good pension and.........white hair....

 

Drive on.......,(watch the out for the ......pot holes)

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Just kidding......but at $4,300 clams Henry could sell you a ET jr hitch to just mount the crates on...........

 

Long time ago I had a distant relative that drove a Nitro truck all over back roads from a remote plant in the middle of Nowhere N. Dakota to the West Texas oil fields and never drove through any towns of any size..........but as I recall the Nitro vile was suspended inside of a large tank with a jelly of some sort to dampen the road bumps............

 

He did retire with a good pension and.........white hair....

 

Drive on.......,(watch the out for the ......pot holes)

Probably a big vat of Preparation H from squeezing all day ;) (I know bad optics)

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Probably a big vat of Preparation H from squeezing all day ;) (I know bad optics)

A job like that could cause a rectal/cranial inversion,,,,,,,,when your optic nerve gets crossed with your anal nerves. It can lead to having your head up your posterior, and give you a sh--y outlook on life.

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Probably half of the loads I deal with are show loads, Cirque du Soleil, various Broadway shows, Disney on Ice, etc. All of these productions use beyond expensive electronics and lighting. All of them use road cases, usually on casters.

 

http://www.performanceaudio.com/browse/Road-Cases-Live-Sound-Racks/319/

 

None of them would attempt to use the casters for isolating vibration. The casters they use are nothing special, other than high quality wheels, sized for the load and rolling surface. They protect the contents with the shape and type of foam lining, custom cut to keep the items from moving. Vibration comes from all directions when any item is moved, on the stage, being loaded/unloaded or while in the truck. And the stage hands, while not reckless, are under severe time constraints to get the "show on the road". These things take a beating and still perform, night after night.

 

When I was with northAmerican Van Lines, our Electronics and Exhibits division did much research on shipping stresses of expensive fragile electronics being hauled for our customers in an effort to prevent claims. Those are usually a one time shipping event. The road cases used in stage productions are designed to move items to hundreds of venues over many thousands of miles, and be unloaded/loaded hundreds of times, with no breakage.

That is the direction you need to go.

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I will second Jeff's observation, foam liners are the most practical way to pack sensitive parts. There are some machines that use large vacuum tubes in their power supply, they are shipped in boxes with rubber band suspension and foam. Spring casters are really designed to allow them to roll on uneven ground better. They do absorb some shock but, they are like spring ride trucks bouncy.

 

If the equipment is really sensitive to shock there are foam systems with variable densities, to further dampen air or gel pillows come to mind. Another consideration is how much they weigh and size, a small object with great mass needs a different package than a bulky fragile object. You want anything well constrained, the less free space it has the less acceleration it can achieve.

 

Steve

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I'm learning more about casters than I ever thought I would. It's clear to me that a spring loaded caster is not the way to go with this project. Learning what doesn't work is just as important as learning what does work. I think I now have a good idea of the direction I need to go. Thanks everyone for the input.

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Back in the Stone Age........a few years ago.........aircraft instrument shops used to ship very sensitive gyro attitude and directional gyros in a large crate with a star shaped foam insert that isolated a smaller box that had more star shaped foam that isolated the actual gyro.

 

Even more decades ago I flew in third world locations and often glass vials of medicine had to be dropped from fairly fast airplanes well beyond the range of choppers so we would carve a loaf of French bread open like a hot dog bun and then we would place the vile inside and then close the loaf and wrap in duct tape.........in drops from 200 ft alt at 150 mph I never broke a vile in hundreds of drops......low tech but it worked .........the hard part in getting French bread when little kids were starving........

 

Drive on.......( please pass the French........bread)

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