Car seat without bus seats?

Mr4btTahoe · 11-02-2017, 11:37 AM

Hey guys...

So... now trying to work out where my son's seat will be mounted/restrained. The front passenger seat (not installed yet) I've been told is the only safe spot.. however I don't like the idea of him being up front. I like the idea of more steel and space around him.

What are you guys doing for child seat mounting when not using a factory seat in the rear passenger area of your bus? My shorty doesn't have the space for it.

I was thinking about a forward facing seat that could be mounted in the aisle way and be removable... with mounts and restraints anchored to the frame... or a harness bar under the couch ( again anchored to the frame.. not wood) but have been told by countless people that mounting the seat sideways is a BIG no-no. Not sure how force applied to the seat would be any different mounted that way then mounted facing forward and being hit from the side.. but anyways...

Thanks for the input.

stephenbloxham · 11-02-2017, 11:54 AM

Sideways isn't good for the child in an impact.

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Mr4btTahoe · 11-02-2017, 12:35 PM

Quote:

Originally Posted by stephenbloxham

Sideways isn't good for the child in an impact.

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So I've been told... but no one can tell me how it is any different then a forward facing seat during a side impact collision such as someone running a stop light or sign.

So what are others doing?

stephenbloxham · 11-02-2017, 01:02 PM

I'd say side impact would be less severe to a heavy bus. Severe impact is more likely from a sudden stop. Rear facing is obviously best for the very little ones. Side facing child seats are illegal in my country.

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Mr4btTahoe · 11-02-2017, 01:11 PM

So how to implement a forward facing seat when there isn't room for something permanent.

Twigg · 11-02-2017, 03:39 PM

Some people retain a couple of seats to install a booth-style dinette. The rear-facing seat would be a good place for kids to travel.

wunderhut · 11-02-2017, 06:10 PM

Quote:

Originally Posted by Mr4btTahoe

So I've been told... but no one can tell me how it is any different then a forward facing seat during a side impact collision such as someone running a stop light or sign.

So what are others doing?

Side impacts usually happen at a 35mph impact force or less, where head on collisions frequently happen at 100mph force or greater.

Mr4btTahoe · 11-02-2017, 06:46 PM

I guess so... unless a large truck blows a light or something along those lines.

Well I think I've got a plan in mind. I have a small seat that folds down nice and compact. Its fairly narrow as well (going to test fit his car seat on it tonight to see how well it fits).

Now my thought is basically a sandwich plate setup... Cut a piece of 1/8-1/4" plate say 12x12 or so. Drill 4-6 holes in the plate and either thread the holes or weld/capture some 3/8" nuts to it. Mount the plate under the bus body floor and mark/drill the holes up all the way through the floor. Permanently attach the plate via 4 more holes and bolts. Then a couple long bolts with handles on them that will go through the seat mount.. through the floor.. threading into the large plate under the bus body. Would only take a few minutes time to attach and remove the seat from the center aisle... would fold up and fit under the bed for storage once we reach our destination. Should also be narrow enough to squeak by while in place if we weren't stopping for long. The seat has built in restraints so it should work fairly well. I'll beef them up if they aren't up to the task.

I am also tossing around the idea of doing the same thing.. but using L-Track or "Aircraft Track" instead of the large plate. Either way, I think it would be plenty strong to keep him in place... yet be easy enough to remove and stow away.

Thoughts?

Mr4btTahoe · 11-02-2017, 06:51 PM

Or something like this... He used L track.
Transit ordered, future camper, mtb, family van - Page 3 - Ford Transit USA Forum

miscrms · 11-02-2017, 07:44 PM

Having the seat mounted sideways would make a front/rear collision more like a side impact collision. Most car seats in the US are not tested for or rated for protection in side impact collisions. And even when they are they are typically not as good in side collisions as they are in a frontal or rear crash. Front crashes are the most common type of collision, but side impacts are much more likely to result in fatalities including of children in car seats.

In a front collision the child is restrained by the straps, which distribute the force and prevent excess forward movement. This distributed force and lack of head restraint can still injure / kill very small children which is why they go in rear facing seats. Then the force is distributed more evenly across their entire body by the seat shell and the head is supported. The reclined body angle also helps reduce head movement in a rear collisions. In a side collision the straps are often less effective at preventing movement. And the child is thrown sideways until the less restrained parts of their bodies, often the head, slam into the side of the carseat.

The more improvised your seat and attachment method are, the less confident you can be about the results in a crash. Even if the seat used to mount the car seat into is a tested automotive type seat, if it's not mounted more or less exactly as originally intended all bets may be off with regard to the testing done to ensure safety of the seat design. The whole seat, mount, and attachment to the vehicle works as a system in the event of a crash. In the worst case the whole thing could shear loose and be launched with the car seat still attached.

IMHO this is a place to be very conservative with the creativity. We are going with original bus seats with integrated child restraints that will be mounted essentially as originally intended. If you can't do that I'd say the original front passenger seat is the next best thing. If it has one, the front passenger air bag should probably be disabled.

Rob

Mr4btTahoe · 11-02-2017, 08:37 PM

I dont have the original bus seats nor the space for them.

I'm a certified mechanic and fabricator. I've built roll cages... complete frames... suspension components.. etc. I am very confident in my abilities to design a seat mounting system that will be stronger then a factory installed system. In this case, the factory bus seats were mounted using short strips of L track screwed to plywood. A high potential for failure.

The driver's seat was flat bolted through sheet metal with no real form of reinforcement to the floor pan.

Now.. if I go with the plate, it is not only going to be sandwiching 2 sheets of 5/8 plywood but also 3/4 high density foam and the steel framework for the bus body (far stronger then just screwing down L track as the coach builder did). If I go the L track route, it will be secured through the steel framework of the bus body as well and secured every 4-5" based on how it is pre-drilled. Each single mounting stud used with L track has a working load of over 1k lbs and a breaking strength of 4k lbs EACH.

Double Stud Fitting w/ Bolt Thread for L-track - Occupant Restraint Components

Most fall protection designed to catch a man in free fall is rated for 5k lbs. A body during a crash can create upwards of ~3k lbs of force. With only 4 mounts, it would take 16k+ lbs of force for the track system to fail. The plate system would take substantially more as the body and frame of the bus would have to fail completely or the force would have to exceed the shear strength of the bolts holding it together. Keep in mind that most automotive seats are held in place with 4 studs that are typically under 3/8" diameter through single or double layer sheet metal.

With all that said.. I am by no means trying to get creative. I simply want a strong mounting system that will work and fit in the space I have to work with... yet be easily removable as it will be located in the front aisle-way just behind the driver/passenger seat (which is the strongest point I can see in the structure of this bus as it is where the van body meets the bus body. Several large steel hoops go over the drivers head in this area and I'd say are designed to take the stress of a roll-over).

I was just looking for ideas on what others had done when they didn't have the bus seats or space for them. The front passenger seat (which the bus doesn't have) will also be relying on a non-factory mounting system... and will be a last resort.

family wagon · 11-02-2017, 08:39 PM

Quote:

Originally Posted by wunderhut

Side impacts usually happen at a 35mph impact force or less, where head on collisions frequently happen at 100mph force or greater.

eek! I don't know anybody who drives 100 MPH routinely, and certainly not in a bus.

I understand probably what was meant is a head-on collision where the two vehicles are each going 50+ MPH. But as luck (and physics) would have it, a head-on of this sort isn't the same as a single vehicle hitting an ideal brick wall at twice the speed. See physics.stackexchange.com, for example.

Still, the points about child seats being designed for on-axis collision rather than side collision are well made.

golfersmurf57 · 11-03-2017, 01:22 AM

Quote:

Originally Posted by family wagon

eek! I don't know anybody who drives 100 MPH routinely, and certainly not in a bus.

I understand probably what was meant is a head-on collision where the two vehicles are each going 50+ MPH. But as luck (and physics) would have it, a head-on of this sort isn't the same as a single vehicle hitting an ideal brick wall at twice the speed. See physics.stackexchange.com, for example.

Still, the points about child seats being designed for on-axis collision rather than side collision are well made.

I'd drive 100 just tell me how to get this battleship to go that fast I'm lucky to get 70 down hill with a tailwind.

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Tango · 11-03-2017, 10:14 AM

The easiest way to get a Skoolie up to (and over) 100 mph...is to use the Thelma and Louise method.

Chess · 08-02-2018, 06:51 AM

So for someone with minimal welding experience and no desire to use an oxy acetylene torch near a diesel tank, would using bus seats for a dinette from a different school bus be the simplest way to get seatbelts in to hit the road quick?

o1marc · 08-02-2018, 11:06 AM

You all missed it with the 100mph impact. Neither vehicle was doing 100. but if both are doing 50mph and hit head on, it's a 100mph impact.

magnakansas · 08-02-2018, 11:45 AM

look at seats online with integrated seat belts, that should give you some ideas. I am using seat from 2015-2018 ford transit vans. not transit connect. go to a ford dealer with a transit 12 or 15 seater van and look. look online. I think you see what I mean. I have cloth, integrated belts, and recline. the doubles have latch points for baby seats.

william

ennonne · 08-02-2018, 12:55 PM

You can find some guidance in the FMVSS.

Like:

"S4.2.2 Except as provided in S4.2.5, the anchorages, attachment hardware, and attachment bolts for any of the following seat belt assemblies shall withstand a 3,000 pound force applied to the lap belt portion of the seat belt assembly simultaneously with a 3,000 pound force applied to the shoulder belt portion of the seat belt assembly, when tested in accordance with S5.2 of this standard:"

Just an excerpt for one type of belt anchoring. Without the shoulder belt it's a 5000 pound force that's used.

From here: FMVSS search

If you do the math, even 5000 pounds doesn't require very much structure (A single grade 5 5/16" bolt will hold over 5000 pounds along it's axis). It's allowed to deform, just has to hold for the specified time. Myself, I'd consider the FMVSS a bare minimum. Good to be sure it's exceeded when you do some math on you setup.

(I think this is why you see a lot of pretty cheesy seat belts mounts in RVs. Mounted to plywood and stuff. Even if the mount has to meet FMVSS, it doesn't have to be very strong.)

family wagon · 08-02-2018, 01:20 PM

Quote:

Originally Posted by o1marc

You all missed it with the 100mph impact. Neither vehicle was doing 100. but if both are doing 50mph and hit head on, it's a 100mph impact.

That's not correct. Cars crashing into each other head-on each doing X speed is the same as one car crashing into the face of a cliff at X speed (not 2X speed).

Math:
Head-on collision math
newtonian mechanics - Is two cars colliding at 50mph the same as one car colliding into a wall at 100 mph?
Mythbusters on Head-on Collisions

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