Abstract: A seat belt buckle (100) operable with a pretensioner (330) connected thereto for moving the buckle a determinable distance to remove slack of the seat belt about an occupant, the buckle comprising: a frame (102), adapted to be connected to the pretensioner (330), defining a tongue receiving opening (170) to receive a tongue (173) as the tongue is moved in a first direction, the frame having a first opening (126a) therein, and opposing frame sides (108a,b), each side including a latch plate slot (110) arranged generally perpendicular to the first direction and an arcuate slot (112), the arcuate slot (112) including a first portion (112a) generally parallel to the latch plate slots (110) and a second portion (113b) angled thereto, a latch plate (180), having end portions (186) movable within the latch plate slots between a locked position in engagement with an opening within the tongue and with the first opening (136a), a weight assembly pivotally connected to the end portions of the latch plate to generate a