Hi Bill,

 

I believe the tension in the belt itself is not effected by the mere existence of the pivot, but rather, by the angle between the pivot point and the CG of the torso and relative position of the shoulder, torso weight and the peak deceleration (in your case, 6Gs). The pivot anchor, on the other hand, would be subjected to nearly twice the tension in the belt since it is effectively acted upon by two belts pulling on the pivot simultaneously at a very acute angle.

 

 If I remember my mechanics and trig, the problem is similar to that of a suspension bridge. The tension in the cables is much greater than merely the weight supported by the main cables. Similarly, the compression load of the support towers, as in the Golden Gate Bridge, is more than twice that of the weight supported (2 x sin(angle) x tension), but not so nearly as much as twice the tension, due to the rather large angle of the cables as they cross over the towers.

 

Lastly, when I diagram the force vectors, it appears that the lap belt contributes a much greater proportion of the total belt tension than the shoulder belt. Then again, what do I know? I’m not a real engineer, just a wannabe.

 

Best Regards,

Mike