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DIY LATCH system retrofit

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Cars made after 2002 have a LATCH (Lower Anchors and Tethers for CHildren) system in place from the factory, but there aren't any kits available to retrofit older cars. My car, a 1960 Ford Fairlane 500, didn't even come with seat belts, so I decided to custom fabricate a LATCH system of my own to enable the safe transport of my daughter while avoiding the expense and hassle of getting seatbelts put in.
 
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Step 1: Buy hardware

Purchase:
2 x 1/2" thick, x 6" eye bolt w/nut zinc plated
2 x 1/2" nuts zinc plated
2 x Carabiners (locking ones are probably overkill, but get good quality ones that latch into a hook system when closed)
4 x 1/2" lock washers zinc plated
4 x 1/2" cut washers zinc plated


(image shows disassembled parts on left and assembled version on right. The washers will go on either side of the sheetmetal of the car.

Step 2: Make the holes

Remove the lower seat cushion and check the floorpan for mounting locations. The bolts need to be accessible from between the upper and lower seat cushions. My floopan had a handy design stamped into it, marking a good spot to place the bolts, roughly 1/3 away from each other and the sides of the car.

With the upper seat cushion still in place, position the eyebolts so that they are flush against the bottom of the cushion and mark the area that the base touches.

Once the positions are marked, use a punch or drill to make a pair of holes about 1/2" in diameter. While this shouldn't be a problem in most cars, you should check to make sure there are no fuel lines, brake lines, or electrical wires located on the other side of the sheetmetal where you intend to place the hole.
cyrusz1 year ago
This is really great, I love how they sit down below the seat, can passengers in the rear feel them much when sitting on them? I found this looking for latches for my 2001 ford. I do overhead hoisting and rigging and I have several of those eyes in my tool box at work i will grab, the best part is even the True Value ones are graded so they are approved for a load such as this.

So many of you are just so blindly negative, you dont seem to realize the load characteristics of this situation the system is as strong as the waskist link, a 300# test eyelet x2, but the 1" webbing on the child's seat is only about 125# also keep in mind that in a collision not only will the lets say 50# object not apply 100% force on those connections but the job of the webbing is to deform and absorb the pressure before it even gets to the eyelets. So lets say under speed that 50# becomes 500# (which is double the load of the belts the kid is in already) but the belts dont take 500# they stretch and slow the load.

We can go in to some deep physics here but the point is with auto manufacturers is most of this is a "good enough" approach, do you think they really run load from each angle on each bolt in the car, they just bump it up a grade and good enough, these bolts if anything will be the only thing that hold up in an accident.

This is still better than my original solution, So according to all of the folks who think the OEM components are infallible, I say in the 60's no belts means they designed the car to be safe without them right???
jclements62 years ago
I think a lot of people are forgetting that even if you installed seat belts into a classic car, your options for mounting the seat belts are about the same as what was shown here: Drill through sheet metal and hope for the best. Having said that, I would agree with some of the concern that this isn't as safe as possible. Were it up to me, I would make three considerable modifications to this system.

First, I would install a mounting plate to the underside of the vehicle. This is the same thing that they did on old cars for seats (and later on, seat belts). Get a super heavy gauge piece of steel, and weld it to the spot you're going to anchor the bolts. The piece should be as large as will fit, so that the force of an impact is distributed over a lot of space.

Second, I would use larger washers made of heavier duty steel. The Home Depot specials in this instructable just seem far too small to do any real good in the event of a catastrophic crash.

Lastly, I would use high grade steel eyelets with the eye welded together. This would ensure that the eyelets aren't unbent and release the car seat.

(I would also be sure that my carabiner is the heavy duty climbing grade. The one used in the photos looks more like the keychain grade ones I have lying around the house.)

Now, given those changes, I would be more than comfortable with having this system in my own 1960 vehicle. Why? Because first, it's as safe as you can get in that kind of car. Even seatbelts would have to be a custom install like that. Also, if there's a wreck big enough to dismount that system and mom and dad were in the car, that kid's an orphan anyways. The cars of that era were tanks. Sheet metal was several times thicker than what you might have on your 2012 Kia. There are no crumple zones or collapsing steering columns. My point is that in an accident, if you're hitting a newer car, they're going to take the brunt of the impact as your sturdy heavy steel on a boilerplate thick frame vehicle plows through their tissue thin steel and plastic unibody car. Any accident resulting in enough force applied to dislodge this system had at least one fatality associated with it. I'd just about guarantee it.

Over all though, this is a decent idea. With a little reworking, it could provide something that would at least allow the use of this car. I'm not saying that I'd drive the kids everywhere, every day in it, but it's a classic car. They get driven on Sunny Sundays and in parades.
An interesting video of just the type of thing you mention in your post: a collision of a 1959 Chevy Bel Air into a 2009 Chevy Malibu. The Bel Air takes a bigger beating than I would have ever guessed:

http://www.youtube.com/watch?v=cJrXViFfMGk
Non Rated Carabiner Caution:

I must confess that I clicked on this instructable just to read the snarky comments. However, I feel compelled to contribute to the discussion.

I have been a more or less active climber for the last 13 years and have to do quite a bit of on-site engineering for my job. I have witnessed materials failing under various conditions. I have been accused of over-engineering and probably rightly so. However, if the risk is low, I tend to give other's designs the benefit of the doubt.

My primary concern is the carabiners used. I agree with jclements6 that the ones in the picture are certainly keychain grade. They were probably just for show until proper load-bearing ones could be installed, and the child in question has outgrown the seat by now anyway. I just want to comment in case others want to duplicate. Any climbing/load-bearing grade biner will have either a pin or other mating surface that will allow the gate (part that swings open) to be held in tension when the body of the carabiner deflects under load and pulls on it. This actually makes it impossible to open the gate under load because the pressure against the mating surfaces effectively 'locks' the biner. They will also have a load rating stamped on the side, usually over 18kN or 2,000lbs (some steel hardware is marked in lbs for the static load, not kilonewtons for force). Also, I agree with mackamitsu that aluminum carabiners should be checked periodically under any circumstances, but especially if used in conjunction with steel. They will wear even from repeated low-force wiggling, ie. child in a car seat, cornering, etc. Steel-on-steel is always better.

On the anchor itself, I guess it all depends on the quality of the metal in the car. This one looks well cared for and not too rusty, but I would second (or maybe third) the recommendation of bigger washers. Lots of extra strength and peace-of-mind for $1 worth of hardware. Backer plates are probably overkill, depending on the thickness of the metal, but I would probably do it anyway. Also, the anchor would be stronger if a bigger bolt were used or the nuts were threaded as far up to the eye as possible to reduce deflection under load, but it too would probably be overkill. It is not fun to think about, but derek244 makes a good point; if you think about the shock load required to make that eye bolt elongate enough to fail being applied to the rest of the car and it's occupants, the picture isn't pretty.
mackamitsu5 years ago
torklugnutz, Brilliant, all the materials you used are more then adequate. The only thing I can think of to reinforce the base would be to use 10G plates approx 4"x4" between the body steel and the fender washers. This will give you better spread of force on impact if you were ever in an accident. It will also distribute the load shift much better and put less stress on the body steel. Don't forget to check the biners for wear every couple of weeks, so they are always in good repair. You could put some teflon spacers in to minimize the contact points. Thats my 2 cents.
thinking of adding some latch points to the cargo area of my wagon. this is good info. def want to be safe, also want to be legal. thanks for the pointers.
before I forget, truck supply stores have better anchor eyebolts that would be the only thing I'd do different.
danlyc2 years ago
Hi All,

Appreciate any comments using the setup below.

I have read thru most of the comments beside the point about this is not tested by professional and also metal fatigue at the point of drilling.

What if I do the following?

Instead of drilling an addition hole to the car chassis, I will reuse the car seat bolt itself. I am driving a mini MPV. the middle row car seat is fasten to a rail and in turn the rail is fasten to the body using bolt and nut.

I have check that the similar model that come with ISOFIX is actually fixing to the car seat instead of the car body. Even the current car seat bucket is also fix to the car seat.

I managed to find carabiners that are certified up to 2000lbs.

Assuming if I can find equal strength material to strap it around the rail or somehow secure this to the car seat system, how different is this compare to the the isofix.

I have try using the seat belt to fasten the baby seat, I am a bit concern as it still move around due to the way the car seat is design. A latch or something that can help to fasten it tightly will be excellent.

Appreciate all comments. If the car seat existing bolt is not strong enough to hold the force during accident, it doesn't matter whether the "new" latch is strong, it will still break, right?

I scout few cars with isofix, the hook that are used are so thin so I am really confused if it can actually even take a 1000lbs force.

Thanks.
I did something similar to this on our Volvo 9 years ago. It came out a year or two before the latch system and I liked the idea of easy access. I used something like this - 1/2" Quick Link Chain Repair Link (see http://ep.yimg.com/ca/I/cvfsupplyco-store_2106_15067902) to attach a short lenght of chain, about 3 or 4 links, just enough to come out of the seat. I attached the repair link to the two inside seatbelt attachment points and then secured the seat to the chain. Once you ratchet the seat down, it did not move. I liked having my son in the center of the car, too.
derek2443 years ago
I commend the author of this subject for doing this. Many of you are under the impression that car makers use some type of special metal in their brackets that withstand a million pounds of force. Others bash the author for putting his childs life in danger. Interesting. Do you all have your children riding in the absolute safest car? Are your car seats made out of some type of industructable material? Do you really think the amount of force required to completely sever the eyebolts will not have an effect on the other components in the car seat? I have made my own latch and tether brackets for my daughters Recaro child seat out of 1/4 inch steel and used the factory mounting points and grade 8 bolts in my 1970 Buick. There is no aftermarket kit available for us classic car owners, so we must use our common sense to make the trip safer for our loved ones. The forces required to cause thick metal brackets and high strength hardware to fail would mean the actual accident is extremely severe and not survivable regardless of safety equipment used. I drive a 2009 Honda Civic and have inspected the LATCH system on this car. It is much thinner and less substantial than this authors design. Now, I would reinforce the bolt mounting point a little more, but do you really know what it would require to rip the bolts, nuts, and washers completely through the floor?
 
The amount of technology in todays cars (crumple zones, SRS's, belt pretensioners, ABS systems, VSC systems, etc.) cannot be replicated and are much more of an issue in survivablity in a crash than this set-up will ever be. Loose and improperly installed car seats by parents far out weighs this type of modification. In 20 years we will wonder how we ever transported our loved ones in todays unsafe high tech cars and equipment.
It's not a matter of the car seat failing or the hardware used to mount it failing. It's a matter of whether or not the points where the anchors are installed are fully reinforced metal, that will prevent the washer from deforming the metal and pulling right through the drilled hole.

I would recommend more than just heavy duty washers. A 3" square of 1/8" thickness steel plate welded to the underside of the bodywork would be at least adequate to distribute the forces and prevent deformation of the anchor point holes in the event of a collision.

(I'd consider it to be over-engineered, but my child's safety is worth over-engineering.)
I like this project, I even thought of doing myself. But I have some concerns. I get the feeling that "curtisjoewalker.com" is single! LOL Is this Mom approved?

Here are my concerns:
1. Latch systems are tested. Is this? Any part of it?
2. Look at those "eye bolts" notice how it is essentially a piece of metal bent to a circle. On impact would they bend out and release the car seat? How about at least getting them welded shut. Tie a cider block to it and drop it off a parking garage. Where does it fail?
3. They make "body washers" for the bolts of the seat belt. They are huge washers meant to distribute force so the bolts won't rip out of the body of the car.
4. It's just hard for me to take this seriously when you say something like this: "safe transport of my daughter while avoiding the expense and hassle of getting seatbelts put in." Seatbelts might be more expensive than your lag bolts, but they go in *just as easy* as the work you put in for this.
5. Did you consider actually buying a *real* latch anchor and putting that in? At least that way you get a tested product, some some hardware store mish-mash.
Sorry to sound harsh, as I said I thought about doing this myself. My wife, rightly, thought I was a moron. It's our kid we are talking about here.

Ok OK that said I take my dog on my motorcycle. See, I *am* am moron, don't listen to me.
torklugnutz (author)  swissarmychainsaw4 years ago
1. No. The products all have a certain load rating on their packaging, but I didn't do any math or computer modeling to figure out the failure points.
2. The eye bolts are quite thick, and while they aren't welded, I think the amount of force to distort them would probably turn a human baby into jello.
3. Washers are a good point. I think mine are good enough and that's what they had on the shelf at Home Depot. Bigger wouldn't hurt.
4. Hassle = damaging the period accuracy of the car interior. Expense is about $25 per seat plus installation. There are no such things as accurate rear belts for my car. They simply did not exist.
5. I did look at getting a factory LATCH kit, but the dealers don't sell them. The best I got was the top latch anchor point retrofit kit, which isn't useful.

PS. yes, it's mom approved, though she's not an engineer either.

Bottom line, it's an antique car and this is the best way to put a car seat in it. Aftermarket seat belt kits would bolt in in virtually the same way and be ugly.
Its not so much the child becoming jello as much as the child being the force that will make the eye bolts jello. Your talking the child's weight multiplying by powers depending on the impact.  example: a child at 10lbs would require 300lbs of force to restrain the child at 30 mph. So how heavy is your child and how sure are you about the strength of the eye bolt.
You need to know more than the speed of the car and weight of a child to measure the force. You need to know the deceleration and what distance the deceleration it is over OR you need to know the number of Gs. Looks like you are assuming 30Gs which is probably about right for most accidents but they certainly get worse that 30Gs.
Yes, but I am generalizing a point. The other thing one should note is that the bolts are in the sheet metal not the frame. Another factor for fail. Sorry, neat Idea but not worth the risk of my or anyones progeny.
classtopher3 years ago
This is clearly a controversial topic and the standard disclaimer which applies to many instructables should apply here "dont try this at home". However, human progress has been due to people who "try things". I am not an expert in the physics of automobile crashes, but I do have a decent physics background. I think this is a very interesting instructable and thought I would take a swag at some of the basic physics involved. The previous disclaimer should apply to this analysis too. Aside from the question whether not to try such a thing, the controversy seems to surround the strength of the eyebolts and other hardware and if they would be strong enough to hold up in an accident. Many people have given their thoughts but not too many calculations in the comments, just gut feelings.

The human body can only withstand amount of G's (which are multiples of the acceleration due to gravity on Earth which is 9.81m/s2). The accident that killed Princess Dianna subjected her chest to 70Gs (according to PBS). Her car was going 80mph and essentially slammed into a concrete wall. Anything above 30 Gs is a VERY serious accident. Assume a head on collision in which the passengers are subjected to 50Gs. 50Gs (490m/s2) would be a passenger strapped into a car going 50mph hitting a concrete wall and the car and the car going from 50mph to 0 mph over approximately 3 feet (3.2 feet = one meter). That assumes the front of the car would crush 3 feet which is less true for older cars that do not collapse and absorb as much energy as newer cars) on impact. It also assumes the deceleration is constant over the 3 feet of deceleration. If a 40lb (18kg) human was strapped to a carseat and was subjected to 50Gs the resulting force on the human is 8899 Newtons (F=MA). Fasteners are rated according to mass (lbs) not force, however, to compute the force it is assumed that the "A" (acceleration) in "F=MA" is 9.81m/s2. So if a fastener is rated at 1000 lbs (453.6kg) the equivalent force would be 4449 Newtons. Assuming the force is distributed equally between the two anchor points, each anchor could be subjected to 4449 Newtons and combined 8899 Newtons and therefore the 50Gs. So one might decide to go with fasteners rated to 2000lbs for 100% margin. This is just a swag at the kind of calculations that one can make in convincing themselves that they should or should not do something like this. Or perhaps might influence your choice of fasteners. You should consider the same physics in deciding how the fasteners could be anchored to the car itself.

In full disclosure, I did something similar to my car. My child weighs 20lbs and all of the fasteners have 100% margin at 70Gs and I ran the normal lapbelt through the carseat too just to be safe.

As others have said, operating a vehicle alongside other vehicles is inherently dangerous and we take risks in most things we do. Slow down and drive defensively.
This looks like a great idea and it retains the original look of the car. People don't understand what it's like to own a classic car like that. They just think you care more for the car than your daughter. But I know you wouldn't have bothered figuring out how to install her seat if that were true. I don't know why people are upset. Looking at what you've done and looking up the shear strength on the parts you've used I'd say you have more than covered your daughter's safety. From what I see the car seat or the car seats belts would fail before your eye bolts and carabiners would. Kudos to you and boo to the naysayers.
iamflashman3 years ago
First of all, nice article. I would just suggest that instead of regular eye bolts, you can purchase fully closed eye bolts at a tractor supply or fastenal. They support in excess of 1000 lbs depending on the size. They also are shouldered so they bolt directly to the floor and do not allow for the torque effect that you would have just bolting regular eye bolts down. Secondly, I have been reading the comments and find it amazing how all of these self professed experts have no idea what they are talking about. They talk about seat belt anchors like they are some magical thing that automobile manufacturers invented. I recently ordered a seat belt kit and the hardware provided for the anchors (and these are for an adult mind you) were grade 5 bolt 7/16" bolts. The anchor was merely a 3" grade 8 fender washer on the bottom of the floor pan. These kits meet all federal regulations and are no where near as strong as a good grade 8 closed eye bolt with a proper washer on the back side. I can promise you, none of the people commenting against your idea of ever worked on or installed any type of seat belts or bothered to do any research for themselves. Race car drivers count on the eye bolts I descrive above to save their life in a 100+ mph crash. These are full grown adults travelling at speeds you should never go with a child in the car!
hammer98764 years ago
Just curious. Is this still "Mom approved" after she reads the comments here?

I suppose this is better than no car seat - or seat belt - at all, but there are good carabiners used by climbers who bet their lives on the things and there are cheap carabines sold at big box stores which are to be used on nothing heavier than keys. 
Amir4 years ago
I feel the need to come to the author's defense after some of the comments I've read voicing concerns over the latest safety requirements issued by the Ministry of Truth.

I'm  not an engineer. But I do have some recent experience with 1/2 eye bolts.

I don't believe that any survivable vehicular crash could exert enough force to cause those bolts to fail, regardless of whether or not they're intended for such an application.

I'm flagging this one.  This is a horrible idea.  Drive your child in another car instead of taking the risk. 
Lower anchors that come with vehicles are tested to withstand a certain amount of weight. Some comments from auto manufacturers have indicated that the anchor itself is more likely to deform in a crash than the lower LATCH anchor, but in this case, you could be looking at carseat failure at an incredibly low weight.

Carabiners aren't designed to withstand thousands of pounds of force, and when you consider that this setup would be the only thing holding the carseat in the vehicle, failure most likely = ejection of the child and carseat.

I'm a child restraint systems technician and could never condone anything like this. If I was at a roadside check and a vehicle came through like this, the parents would be held until a vehicle with an appropriate belt system could come and provide transportation for the child.

Putting the extra money into seatbelts is the only way to make an older car safe for a child restraint, as well as the adults in the vehicle.

It's also worth saying that attaching a carseat by a method not approved by the manufacturer would completely void carseat warranty in the event of a crash, and you wouldn't know how the rigged system would even work until a crash - so your child would be the very first crash test dummy.

Lower anchors aren't any safer than a vehicle seatbelt, so there is no advantage to putting them in.

I understand that this is an idea meant to help parents, but if a parent were to do this and use a carseat this way, they would be putting their child's life in danger.

Maybe you could make a how-to about how to install seatbelts in older cars? Many of them have pre-designated locations and you can buy seatbelts and the assembly online.
Here are some links on tensile stregth of I-bolts and carabiners.
http://www.patrollersupply.com/equipment/item_2604.asp
http://www.boltdepot.com/fastener-information/Eye-Bolts/Machinery-Eye-Bolt-Working-Load-Limits.aspx
What kind of force are you expecting to sustain? I can't believe the suggestion that a DIY steel kit would not be more than adequate, if not stronger. I am a helicopter mechanic and I am going to do this to my Cherokee. I have no qualms about it, fellow Marine's lives are in my hands everyday. Grade 8 steel hardware, what's the problem? Do you have stock in the manufacturers?
Carabiners aren't designed to withstand thousands of pounds of force

To be certified by the UIAA, the minimum shear strength for a Type K carabiner is 25 kN, about 5600 pounds. See pages 5 and 6 of that PDF.

I'd worry a lot more about the eyebolt than the biner.
Thanks, that's really interesting to know about the strength of this type carabiner. So you are probably right about the eyebolt being most likely to be the point of failure. For comparison, the entire LATCH system is tested at a minimum 15kN, the LATCH system is comprised of both the lower anchors and the top tether anchor. - which is yet another problem with this setup...
torklugnutz (author)  snowbird25ca6 years ago
I'm curious about the roadside check comment too. They don't do those where I'm from, but I would have to imagine that I'd cruise right through due to the age of my car. This instructable isn't for people with cars made after 1965, or whenever lap belts became standard and it would be a lot of hassle for someone with a newer car to go to for a minor convenience. Doing an instructable on installing seat belts would be more or less the same as this, but with lower mounting holes and the ease of using hardware included in the seatbelt kit. I appreciate what you're saying and I think you're coming from the right place, but I also think you're looking at it as someone who owns a newer car and you might be overthinking things a bit.
torklugnutz (author)  snowbird25ca6 years ago
Climbing carabiners are designed with shock loads in mind, as they are the only thing keeping a climber from falling to his death from a cliff face. As for voiding the carseat warranty in the event of a crash, that's gonna be the least of my problems. The advantage of using lower anchors is two fold: First, they're easier to use. Second, it keeps my backseat from having lap belts lying all over it. If you have a new-fangled car built after 1965, or so, you probably already have them. When my car was built, there were no automotive seatbelt rules or guidelines. As an added option, they (2) were available for the front seat for $20.60 and "so well constructed that they exceed Civil Aeronautics Administration requirements" There are no approved methods of putting a car seat into an antique car, just as there are no regulatory bodies requiring a manufacturer funded retrofit recall. We're on our own to find solutions for these old timers. In the same breath, I hope to be able to use these LATCH points in the future with an aircraft-style removable lap belt.
Your child's safety really needs to be more of a consideration than how the lap belt is going to look laying across the back seat. If there isn't a safe place to install seatbelts in the car, then the car cannot be used to transport children. It's not a matter of "well, I hope this works because I don't have any other options." When the other lapbelts aren't in use, buckling them and tightening them will remove the risk of the latchplate becoming a projectile in a collision. If you read your carseat manual it talks about approved belt systems. Rigging up anchors so you can use LATCH, and attaching carabiners to alter the LATCH belt itself isn't one of them. ;-) And you're right, voiding the warranty is the least of your problems if you have a carseat flying around your car with your child's life at risk as well as your own... Lower anchors did not become mandatory until Sept 2002. Vehicle manufacturers also impose a maximum weight limit for using their anchors, so even in vehicles with lower anchors, there almost always comes a point where the vehicle seatbelt will have to be used for the installation unless you have a lightweight child or graduate said child to a booster prematurely. LATCH isn't safer, and it's not always more convenient. It was designed to be easier to use, but in some instances it's harder. I believe that there are car restoration forums that do have information on how to safely retrofit seatbelts into antique cars. I know for a fact that it is possible. What you have right now just isn't safe. Period. (As an afterthought, lower anchors are also regulated in terms of the distance they must be. Not that eyebolts are even comparable to lower anchors, but there are a lot more problems here than just the strength of the attachment points.)
I remember our comet didn't have seatbelts. That thing was great. We were the second owners when the people traded it in the early 1990's. My dad was driving it and was at a stop sign and this old woman gets out of her car and tells my dad she had bought that car brand new with her husband.
canmom4 years ago
OMG I seriously hope this is a joke. This is NOT safe at all in ANY way shape or form. You can't retrofit the lower anchors into a vehicle and there is a reason why (there is more to the system BTW). If you have to have LATCH... get a newer car. Furthermore, you can't use a beaner clip to make shift your own LATCH connectors. Seatbelts and LATCH are equally safe... there is no reason to do something like this. Please, no one due this... it is NOT tested and NOT safe!
Are you serious? This is NOT safe. I have an idea, why don't you call your car seat manufacturer and ask them if it's ok to use the seat in this manner. Be sure to tell them all about your handy little project. I'd bet you the world that they would tell you NO WAY. How can you put a price tag on your child's safety? Geez, if you don't want to mess with your beloved "classic" car... maybe you should park it while you have your child with you. Buy a different vechile to transport your child in. You are a moron, not to mention a horrible parent for thinking this is safe, and I hope to God your child is not riding with you when you get in an accident. Your poor child is at major risk over your stupidity.
joker4025 years ago
My truck is grandfathered in with regards to having the kids in a booster (since in the back i only have lap belts). Might be a similar situation. FYI, this type of thing is often done in ORV's so kids can ride in them.
al65 years ago
I don't know why people think rigging their own inventions is safe, if if were you'd be a rich person right now. Using you own child as a crash test dummy, what a shame. Not to mention that the lower anchors do not make the seat safer, just more convenient to use. The seatbelt is the safest and has not weight restrictions. This is why we have Child Protective Services.
torklugnutz (author)  al65 years ago
How are seatbelts fastened to a car's chassis? They are fastened with bolts. It is the same basic thing as I have done here.
al6 torklugnutz5 years ago
(removed by author or community request)
torklugnutz (author)  al65 years ago
Rear facing vs. forward facing: Moot point. The carseat is forward facing. There is no other way to install it. The old infant seat was rear facing. In any case, it is outside the scope of this instructable to debate the merits of carseat design. I did install 2 sets of seatbelts in the front as originally available as options from Ford. They cost, I think, about $20. Installation was identical to this latch system and involved punching holes in the chassis to mount them to. Mounting to the car's frame would not be possible, because the frame does not cross at any point that would be practical to mount to, and punching holes into the frame would be quite difficult. To install the carseat, I used the included LATCH belt included with the seat. The infant seat, when I used it, I had in the front passenger seat, but because of the lack of shade and the inconvenience of blocking passenger access on that side of the car. A major hassle with a two door car.
ajmcc5 years ago
Congratulations - having a latch connector is much safer than just using the lap belt system. I wish my older honda had that option. One question. Did you give any thought to using larger fender washers to back up the nuts? I am not so worried about the force during a collision. But the fatigue of the metal around the washers due to all the flexing of the long eyebolts. Thats alot of torque that could be translated through a small washer in to soft steel. PS - the upholestery in the car looks great and congrats looking out so well for your kids.
Number 1, the latch is NOT safer than the seatbelt and it has a 40-48lb limit in most cars, the seatbelt does not. The latch was not designed to be safer than the seatbelt, it was designed to be easier to use (which IMO it is not). Not to mention that this rig up is not a latch system.
drsteevo5 years ago
This seems like a really bad idea, please reconsider your engineering. A washer and bolt through sheet metal seems to be your weakest point and it may not be as strong as you need -- why take a chance with your daughters life? How much trouble could it be to fabricate a backing bar? And why not use a locking carabiner?
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