Design of occupant arm protection cage
Design of occupant arm protection cage
(OP)
Hi all,
I am working on a job where the client has asked for a protection cage against on-coming traffic. More specifically, the cage is to be mounted to a line marking truck whereby the occupant reaches out from the side of the truck in order to place road markers. The client wants a cage to protect the arm of the occupant in the event of on-coming vehicles passing too close. The maximum speed of all on-coming traffic will be limited to 40 km/hr (25 mph) while the truck will be moving at walking speed.
I was wondering if there are any available standards/guides to design the cage to. I am aware that there are multiple standards for direct impact protection, however, they do not give anything relating to side swipe actions.
Cheers,
I am working on a job where the client has asked for a protection cage against on-coming traffic. More specifically, the cage is to be mounted to a line marking truck whereby the occupant reaches out from the side of the truck in order to place road markers. The client wants a cage to protect the arm of the occupant in the event of on-coming vehicles passing too close. The maximum speed of all on-coming traffic will be limited to 40 km/hr (25 mph) while the truck will be moving at walking speed.
I was wondering if there are any available standards/guides to design the cage to. I am aware that there are multiple standards for direct impact protection, however, they do not give anything relating to side swipe actions.
Cheers,





RE: Design of occupant arm protection cage
-handleman, CSWP (The new, easy test)
RE: Design of occupant arm protection cage
Is that mechanically/electronically limited to 40kph, or politely asked to not exceed 40kph?
--
JHG
RE: Design of occupant arm protection cage
Can you prominently place a couple of day-glo orange steel spikes on handleman's 1" thick gusseted plate? Your worker may be expendable, but there will be concern for the oncoming car's grille and headlights.
--
JHG
RE: Design of occupant arm protection cage
Some possibly useful information on roll cages:
http://www.msauk.org/uploadedfiles/msa_forms/blueb...
Nonetheless, any sort of absolute protection would be essentially impossible. Moreover, building the structure to withstand requirements that exceed crash safety requirements would be difficult to justify.
TTFN

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RE: Design of occupant arm protection cage
No sense reinventing the wheel - with the attending liability.
Alternately, drop your cones from one of these
RE: Design of occupant arm protection cage
Is a lightweight horizontal pole (or poles) with breakaway hinge protruding from the side of the vehicle with appropriate flags or banners, far enough out to encourage oncoming traffic to slow and keep their distance, together with some ordinary, common sense vigilance on the part of the person dropping the cones, not adequate somehow?
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
RE: Design of occupant arm protection cage
RE: Design of occupant arm protection cage
But in all seriousness, my initial thoughts were also more on deterrence than absolute protection. The cage itself has to be able to fold out from the truck so that it doesn't obstruct traffic when the truck is moving to/fro the stretch of road it needs to mark. This means the actual cage can't be solid and energy absorption systems are not economically/practically feasible.
The cage will most likely be there to just appease the client/occupant. I guess the main factor will be painting the cage with warning colours and hope all oncoming traffic is smart enough to steer clear.
Cheers all and thanks again for the the ideas.
RE: Design of occupant arm protection cage
RE: Design of occupant arm protection cage
Or just use an actual wing plow with big diagonal stripes.
Mike Halloran
Pembroke Pines, FL, USA
RE: Design of occupant arm protection cage
Are zombies bad drivers?
Can you place the worker so that they are facing traffic, and can always see what is coming at them? They should be facing forward, and sitting low so that their heads are not down when they are working. Obviously, they need somewhere to dive to when they see something coming at them.
--
JHG
RE: Design of occupant arm protection cage
Caltrans, on the other hand, has at least a few traffic cone placement trucks that use a mechanical placer, so no body parts are at risk:
http://www.dot.ca.gov/research/researchreports/two... which is an option if the cost of infrastructure to protect the worker is too high. I could see possibly only implementing the placement equipment and manually feeding it cones to cut down the cost.
Other:
http://www.centrevilletrailer.com/trailerDetails.c...
http://ahmct.ucdavis.edu/?projects=test-deployment
TTFN

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RE: Design of occupant arm protection cage
It is as drawoh says. The occupant placing the reflector markers are facing the oncoming vehicles. Problem is that they need to look down at where they want to place the reflector marker, eject a glob of glue onto that spot, then place the marker over the glue. This needs to be repeated every few metres over a good 50 km stretch of road.
The truck set up is basically identical to what IRstuff has seen. I'm in Australia and the idea of automating the process is too costly for the state road authority here. As far as I know, the thing with the occupant arm protection cage to be fitted to the side of trucks has never been done before. This is why the client wants to know if the cage can be designed to any relevant standards/codes (regardless of local or international). Does anyone know of any standards to this effect (other than the generic steel design standards - e.g. LRFD, AS4100, AS3990).
Cheers,
RE: Design of occupant arm protection cage
Can the need for the operator to put his arm into traffic be eliminated without automation.
Can some kind of chute or similar be developed that allows the operator to stay within the footprint of the vehicle while allowing the glue and reflector to be deposited?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Design of occupant arm protection cage
One possible approach is to get either a sonar or radar so that the operator can be warned about oncoming traffic. Something with about 50 ft range would give you at least a half-second of warning.
Another option is to put the operator seat and roll cage deflector on a pivot with a breakaway, so that if the roll cage is hit, the breakaway would cause the seat and roll cage to pivot toward the centerline of the truck. The breakaway would also be used to stow the seat closer to the truck centerline for transport.
TTFN

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RE: Design of occupant arm protection cage
-handleman, CSWP (The new, easy test)
RE: Design of occupant arm protection cage
TTFN

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RE: Design of occupant arm protection cage
TTFN

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RE: Design of occupant arm protection cage
I can imagine getting accurate positioning could be a bit trickier but I'm sure someone brighter than me could address that issue.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Design of occupant arm protection cage
How about applying something like Scotch VHB structural tapes to the bottoms of the cones? The worker peels away the backing while looking forwards for oncoming vehicles, and places the cone.
--
JHG
RE: Design of occupant arm protection cage
If the glue could be applied to the bottom of the reflector, the operator could put the reflector onto some sort of gripper or vacuum pad at a comfortable work height, then push the arm out and down to position the reflector on the road.
-handleman, CSWP (The new, easy test)
RE: Design of occupant arm protection cage
Thomas J. Walz
Carbide Processors, Inc.
www.carbideprocessors.com
Good engineering starts with a Grainger Catalog.
RE: Design of occupant arm protection cage
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
RE: Design of occupant arm protection cage
The OP actually outlined the process in question pretty clearly. This is not cones. It's reflectors glued to the road.
-handleman, CSWP (The new, easy test)
RE: Design of occupant arm protection cage
http://www.youtube.com/watch?v=_635Xt3We4E
RE: Design of occupant arm protection cage
Can't see why anyone would attempt to do build a cage when a solution like that is so simple (and safe). Of course now you've just put another person out of a job (but a dangerous job obviously).
One could easily build a system like that for a few thousand dollars.
RE: Design of occupant arm protection cage
RE: Design of occupant arm protection cage
RE: your 4SEP13, 10:52 post.... I like the plows and the big truck. But, there seems to be a bit of a scale problem with the picture. Notice that the circle sawn pine board fence behind the truck must have about 4' +/- wide boards, 20' + high, or there is something fishy about that truck. That’s one hell of a snow fence.
RE: Design of occupant arm protection cage
RE: Design of occupant arm protection cage
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.