Seat belt buckle

A seat belt buckle adapted to releasably engage with a latch plate insertable within a latch passage in the seat belt buckle, said seat belt buckle comprising:

• a rigid frame having an open forward end defining said latch passage, an opposite rearward end adapted to be attached to a seat belt, an apertured rectangular base plate, an upstanding side wall extending from each longitudinal edge of said base plate, and a fixed bar extending across the width of said base plate between the forward and rearward ends thereof, parallel to, and spaced apart from, said base plate, said fixed bar being secured at each end thereof to a respective side wall;
• a locking member pivotally supported by said frame side walls so as to pivot about an axis substantially parallel to, and spaced apart from, said fixed bar of said frame, between a latched position, in which the locking member retains said latch plate within said latch passage in the buckle, and an unlatched position, in which the locking member is held clear of said latch passage, the locking member including a depending lock bar extending therefrom, which lock bar extends across said latch passage and into an aperture of said apertured base plate of the frame when the locking member is in said latched position, there being a predetermined clearance existing between a forward edge of the lock bar and a forward edge of the aperture when the locking member is in said latched position;
• a shaped blocking member slidably mounted upon said pivoted locking member for longitudinal movement relative to said locking member between a first position, where the locking member is in said latched position and the blocking member is interposed between said fixed bar and said locking member to block any pivotal movement of the locking member towards said unlatched position, and a second position, where the locking member is in said unlatched position and the blocking member engages the fixed bar to retain the locking member in said unlatched position;
• a push button slidably mounted on said frame side walls above said latch passage, for longitudinal movement relative to the frame base plate so as to move said blocking member from said first position to said second position;
• and a spring means located between the blocking member and the locking member which biases the blocking member towards said first position;
• and the locking member is pivoted in the frame side walls by elastically-deformable integral wing portions, which wing portions will elastically deform when the buckle in a latched condition is subjected to applied loads beyond a predetermined limit, so as to allow the forward edge of the lock bar to make contact with the forward edge of the aperture in the apertured base plate.