Anyone have kids driving? I do. Wondering if an how to install 3 point belts in back seat. I would like two in front and two in back. Anyone got a suggestion?
67 Installing 3 point seat belts in back seat
Paul Hogan
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Anyone have kids driving? I do. Wondering if an how to install 3 point belts in back seat. I would like two in front and two in back. Anyone got a suggestion?
I want to do this too. I spoke with billy from morris classic concepts and he didn't have anything yet, and don't know if he is working on it, but when I forwarded the pics of the original mounting (3rd) location on the package tray shelf, he said he had seen the pics but didn't know if that would be a strong enough/suitable location for them to anchor. I am hoping it is, but I think bugging him again about this couldn't hurt! So send him an email, or call and see if they have anything in the works! I think they would sell extremely well.
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Installing 3 point seat belts for back seat
We are working on a set up now. There will be extra bracing added, as GM
didn't make the panel double thickness as the drawings reflect. The system will be very easy to install. Keep in touch. Billy
We are working on a set up now. There will be extra bracing added, as GM
didn't make the panel double thickness as the drawings reflect. The system will be very easy to install. Keep in touch. Billy
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516 Posts
Installing 3 point seat belts in back seat
We are having mounting systems fabricated now. As with any project we
have to keep fitting and adjusting the template until we get the correct fit
and a safe product. The bracket will have three mounting points,4 bolts and will require the installer to drill a 1/2" hole.Then we will have a laser file made to cut the bracket. Then a metal fab shop to bend offsets in the bracket to fit properly. Billy
We are having mounting systems fabricated now. As with any project we
have to keep fitting and adjusting the template until we get the correct fit
and a safe product. The bracket will have three mounting points,4 bolts and will require the installer to drill a 1/2" hole.Then we will have a laser file made to cut the bracket. Then a metal fab shop to bend offsets in the bracket to fit properly. Billy
I started researching this last year and talked to one of the board members CarlC about it. Here is some info he passed me:
Carl, thanks for the pictures and information. I am going to try and
install them in the next month or two. I will probably email for more info
then. One question about putting the seat belt "loop" on the package tray.
Do you think it was necessary to strengthen the area up (where it bots to
the tray) or would a fender washer on both sides of the tray have been
enough?
Chris,
The loop attachment point has a much higher loading than the mechanism. Since the belt is pulling both forward and down the actual load is higher than the belt tension by a factor of 1.4 and pointing forward and down at a 45* angle. It might be fine with just washers but since there is no practical way to non-destructively test it I decided to be cautious and install the plate.
Here are some pictures he sent me:
I haven't started this but it is on my list of to do stuff (since I take my small children for rides in my car). BTW, I am currently using lap belts in the back seat.
Carl, thanks for the pictures and information. I am going to try and
install them in the next month or two. I will probably email for more info
then. One question about putting the seat belt "loop" on the package tray.
Do you think it was necessary to strengthen the area up (where it bots to
the tray) or would a fender washer on both sides of the tray have been
enough?
Chris,
The loop attachment point has a much higher loading than the mechanism. Since the belt is pulling both forward and down the actual load is higher than the belt tension by a factor of 1.4 and pointing forward and down at a 45* angle. It might be fine with just washers but since there is no practical way to non-destructively test it I decided to be cautious and install the plate.
Here are some pictures he sent me:
I haven't started this but it is on my list of to do stuff (since I take my small children for rides in my car). BTW, I am currently using lap belts in the back seat.
interesting pics...
and wouldn't the load on the upper mounting point be sqrt2/2, not just sqrt2? as in .714, basically taking 71% of the load assuming a 45* angle? I don't think the mounting point load would be more than the actual load due to any angle for that matter? Does that make sense? The load would be distributed between the mounting points, but not necessarily evenly (all depends on relative angles with one another right). Also, there is actual torque force applied to the mounting stud or w/e that is on the package tray vs. if it was say hanging on the ceiling (not as much anyways).
All that asside it has to be strong. But, those belts look decent, although I would go for black!
and wouldn't the load on the upper mounting point be sqrt2/2, not just sqrt2? as in .714, basically taking 71% of the load assuming a 45* angle? I don't think the mounting point load would be more than the actual load due to any angle for that matter? Does that make sense? The load would be distributed between the mounting points, but not necessarily evenly (all depends on relative angles with one another right). Also, there is actual torque force applied to the mounting stud or w/e that is on the package tray vs. if it was say hanging on the ceiling (not as much anyways).
All that asside it has to be strong. But, those belts look decent, although I would go for black!
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Whos seat belt is it in picture? For the rear belts? Wes
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Billy,
I'm down for a set for 69 when they are ready. I think you will sell those new kits like hotcakes.
I'm down for a set for 69 when they are ready. I think you will sell those new kits like hotcakes.
My thoughts too.... I would feel much better having a set of them in the car when I take my Godson out for a cruise around town.
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Installing 3 point seat belts in back seat
Wendall,Thank You and Everyone for buying our products. Our goal is to make a Safe and Quality product. We make our products from quality materials and we have craftsman making our products that is some of the reasons our products are priced higher than other companies but we won't and can't compromise Safety and Quality. I'll keep everyone updated on the rear seat belts. Thank You, Billy
Wendall,Thank You and Everyone for buying our products. Our goal is to make a Safe and Quality product. We make our products from quality materials and we have craftsman making our products that is some of the reasons our products are priced higher than other companies but we won't and can't compromise Safety and Quality. I'll keep everyone updated on the rear seat belts. Thank You, Billy
There is the forward force component (shoulder belt load) and a similar downward component (to the retractor mechanism) in my setup. Since the loadings are similar (assume them to be 1), then the resultant at the package tray belt guide mounting point will be the belt load * sqrt2 at a 45* downward angle.
The actual loading during an accident at the belt guide attachment point will be approximately the belt tension * sqrt2 as long as the right triangle arrangement remains in place. If the angle decreases, the loading increases. If the angle increases, the loading decreases.
The sqrt2/2 cannot be used to determine the loading at the belt guide point. The loading at the belt guide point can only be determined by the belt tension. The belt tension (under load) is calculated by figuring out what belt tension would be required to restrain a mass of X accelerated at Y with the belt at an angle Z (simple case). The sqrt2/2 cannot be assumed since the belt angles used to restrain the load are not usually 90*, and there may be more than 2, usually 3, and could be as many as 5 or more mounting points to share the load.
I bought the belts from seatbeltpros.com years ago, long before Billy came up with the kit. Given the amount of fabrication and welding I did, I'd go with his.
The actual loading during an accident at the belt guide attachment point will be approximately the belt tension * sqrt2 as long as the right triangle arrangement remains in place. If the angle decreases, the loading increases. If the angle increases, the loading decreases.
The sqrt2/2 cannot be used to determine the loading at the belt guide point. The loading at the belt guide point can only be determined by the belt tension. The belt tension (under load) is calculated by figuring out what belt tension would be required to restrain a mass of X accelerated at Y with the belt at an angle Z (simple case). The sqrt2/2 cannot be assumed since the belt angles used to restrain the load are not usually 90*, and there may be more than 2, usually 3, and could be as many as 5 or more mounting points to share the load.
I bought the belts from seatbeltpros.com years ago, long before Billy came up with the kit. Given the amount of fabrication and welding I did, I'd go with his.
ha ha ha, I was waiting for someone to chime in here!
I still think I am right about this, and I know it would technically vary with the more mounting points and disperse more and more. But, your force vector is the body moving in basically a straight line forward... but because of the shoulder strap etc, the force gets absorbed at multiple points, and thus the force at any one point cannot exceed the total force in the system... it just can't. At least that makes perfect sense in my head!
I am not trying to give you a hard time, I was just trying to set up a basic force vector drawing and it wasn't clicking for me.
Bottom line is that the mounting points will need to be strong, which I think we are all in agreement.
The belt load is created by the body moving forward. No argument there.
So, instead of using 1 for a belt load, let's call it L. L is the same along the length of the belt during tension.
The load L of the belt goes up the shoulder and turns horizontally. The load L has not changed in scale, only direction. Now the belt load must turn downward through the guide. Assume the belt guide is a pulley (zero friction.) So now there is a horizontal and vertical belt load of L acting on the pulley. Draw a FBD of a right triangle with equal legs of L. The hypotenuse is R.
L^2 + L^2 = R^2.
sqrt(L^2 + L^2) = R
sqrt(2L^2) = R
L*sqrt(2) = R
Assume the load = 1
R = sqrt2, or approximately 1.414 at a 45* downward angle.
So, whatever the belt load is, the belt guide in my example/car sees a loading of 1.4L @ 45* down. I think what you are thinking are the loads at the belt ends. I wish it was easier to draw triangles on these reply sections....
So, instead of using 1 for a belt load, let's call it L. L is the same along the length of the belt during tension.
The load L of the belt goes up the shoulder and turns horizontally. The load L has not changed in scale, only direction. Now the belt load must turn downward through the guide. Assume the belt guide is a pulley (zero friction.) So now there is a horizontal and vertical belt load of L acting on the pulley. Draw a FBD of a right triangle with equal legs of L. The hypotenuse is R.
L^2 + L^2 = R^2.
sqrt(L^2 + L^2) = R
sqrt(2L^2) = R
L*sqrt(2) = R
Assume the load = 1
R = sqrt2, or approximately 1.414 at a 45* downward angle.
So, whatever the belt load is, the belt guide in my example/car sees a loading of 1.4L @ 45* down. I think what you are thinking are the loads at the belt ends. I wish it was easier to draw triangles on these reply sections....
ah, but you see that when you apply the load to the shoulder strap (ie person going forward in a crash), you don't have an equal load "L" applied both downward and forward as you mention. If that were the case, then yes you would be right. But, as you mention, I speak about the dispersing of the load somewhat via the mounting bolt locations (in this case on the floor or w/e), which DO play a part in the equation. You can think of the shoulder point as a pulley, which is great because then you can visualize the load being transfered around the pulley down to the other 2 mounting bolts. But, in a crash, the retractor doesn't extend belt webbing, it is still and the "pulley" acts as a fixed point essentially, which really doesn't matter in this case, but stay with me!
Let me try to simplify my reasoning here... If you had one teather to the shoulder mounting location (in a one mount system), and applied a force of L to the teather say forward, then you would have a load of L on the shoulder loop location right?
So, adding 2 more mounting points down low just helps distribute the load which is a combined load (not necessarily evenly) of "L" between the multiple locations.
I am just saying that you can't gain force in a closed setup. if the force on the belt at one point is "L", then the force on any one mounting location on a multiple mounting location setup is going to be less than L.
Wouldn't you agree that if you had a 10 point harness, that if a load L is applied anywhere in the system that at any given point the load on any one mounting point or loop/pulley is not greater than the initial applied force?
It is also like picking up an engine with a chain that has 2 mounting locations. If your example were true, then you would be better with 1 mounting location, because in a 1 mount system the load would only be the total load, and not 1.414 times the original load. We both know that is not the case as 2 mounting locations are better and stronger than one mounting location of equal material composition, because the force on each mount is less than the original force or in this case weight of a motor.
Ok, I'll stop hijacking this thread for now! If you still don't agree with me, then we can agree to disagree! (even though I am right! aha hahha ahaha)-sorry, I had to!
Let me try to simplify my reasoning here... If you had one teather to the shoulder mounting location (in a one mount system), and applied a force of L to the teather say forward, then you would have a load of L on the shoulder loop location right?
So, adding 2 more mounting points down low just helps distribute the load which is a combined load (not necessarily evenly) of "L" between the multiple locations.
I am just saying that you can't gain force in a closed setup. if the force on the belt at one point is "L", then the force on any one mounting location on a multiple mounting location setup is going to be less than L.
Wouldn't you agree that if you had a 10 point harness, that if a load L is applied anywhere in the system that at any given point the load on any one mounting point or loop/pulley is not greater than the initial applied force?
It is also like picking up an engine with a chain that has 2 mounting locations. If your example were true, then you would be better with 1 mounting location, because in a 1 mount system the load would only be the total load, and not 1.414 times the original load. We both know that is not the case as 2 mounting locations are better and stronger than one mounting location of equal material composition, because the force on each mount is less than the original force or in this case weight of a motor.
Ok, I'll stop hijacking this thread for now! If you still don't agree with me, then we can agree to disagree! (even though I am right! aha hahha ahaha)-sorry, I had to!
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