Child Car Seat Question, Please ?

Hello,
A bit OT, but you folks seem to know just about "everything", so let me please ask:
Son has a Subaru Outback, and a car child seat.
The strap that is meant, apparently, to secure the very top of the seat (from rotating forward) extends from the roof right behind the seat.
Has a simple hook on the end to latch onto the top of the child seat.
It seems to work on a "retractor" principle, the same way the normal car seat belts function.
Question: there is considerable (actually quite a lot) of play in this strap.
Presumably, if it ever senses a forward de-acceleration, it would "latch".
But hard to believe that it would latch before there is a lot of forward movement of the child seat's top.
Is this the way these things are meant to operate ?
Am I missing something ?
Thanks,appreciate your thoughts on,
Bob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

What you're describing is called inertia belts, or reels maybe, if you want to look on the web. They were meant to make people freer to move around when the belt was on.

Probably, but I can see why you think it would need to be different for a baby.

Yes, what year is the car? For some or all the belts on some or all cars, especially I would think more recent ones, BUT PROBABLY ONLY ON THE FRONT SEATS, there are electrically triggered explosions in the retractors, specifically pretensioners, that I think are supposed to lock them, the ones I guess that aren't fully retracted, even faster than the inertia gizmo. Hard to believe. The explosive has to be replaced afterwards.
https://en.wikipedia.org/wiki/Seat_belt http://www.seatbeltsplus.com/Retractor.html http://auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/seatbelt-pretensioner.htm
The pretensioner mechanism uses an explosive charge to drive a concealed piston when sensors detect the signature abrupt deceleration of an accident. The piston, in turn, rapidly drives the spool around which the fabric strap of a seatbelt is wrapped. That incredibly fast retraction of the belt fabric removes the slack from the belt instantly. This extra seatbelt "pre-" tension, moments prior to the full force of impact, pulls the bodies of the driver and front-seat passenger firmly into their seats. This positions them so as to receive the maximum protection benefit of the front airbags

I hit a curb once going about 40mph, and indeed the seatbelt locked as it was supposed to and I only went forward about an inch. The pretensioner didn't go off, and my car has them. The air bag didn't go off either, and maybe that was because when I was working on the dash I separated an electric connector. I didn't mean to do that but it might have saved me from buying a new airbag. The airbag connectors are yellow! I think all of them are.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thursday, July 7, 2016 at 4:02:57 PM UTC-4, Bob wrote:

When my kids were young, we used these clips to "lock" the shoulder strap to the seat strap, eliminating all movement and the need for the shoulder belt to "latch" with hard braking.
https://goo.gl/images/51ekvN
Not sure how it would apply in your situation, but I figured I'd toss it out anyway.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 7/7/2016 4:02 PM, Bob wrote:

I've got them in the back seat of my '08 and '16 Subaru's. Does not take more than a little tug to lock otherwise it lets you slowly move like all other belts in the car. Only in back seat from the roof because it allows three people to belt up there. In front with bucket seats, you only seat two. I don't think my wife used the roof strap but seats grandchildren on one side or the other.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

DO NOT trust any advice except that which comes directly from the owner's manuals for the car and the safety seat.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.