POP-2 papers. By R. M. Burstall. J. S. Collins and R. J. Popplestone. Pp. 61. 21s. 1968. (Oliver and Boyd.)

TLDR: In this article, a safety belt retractor assembly adapted for use in connection with automobile seat or shoulder belts providing normally desired freedom of movement to a wearer during normal driving with the belt snagged into a locked passenger retaining position upon a rapid change of speed or direction of the vehicle.

Abstract: A safety belt retractor assembly adapted for use in connection with automobile seat or shoulder belts providing normally desired freedom of movement to a wearer during normal driving with the belt snagged into a locked passenger retaining position upon a rapid change of speed or direction of the vehicle. A belt is wound on a spring biased rotatable drum, the spring tending to rotate the drum to wind the belt thereon. At relatively constant speed and direction, the belt may readily be unwound from the drum. However, upon a rapid change of direction or speed, ratchet teeth associated with the drum are engaged by a pawl preventing drum rotation and holding the belt tightly. A spring normally biases the pawl to a position out of engagement with the ratchet teeth. However, the spring biasing is overcome and the pawl is actuated to a ratchet engaging drum locking position by a sudden pull on the belt when a wearer is suddenly moved as a result of a rapid speed and direction changes.