Abstract: A buckle system and mechanism for use in a seat belt vehicle restraint system which provides an interlock for ensuring that the occupant has the correct web position for the lap and shoulder belt portions of a three-point seat belt system. This buckle system permits only one tongue to be inserted in the interlock at a time. Moreover, the insertion of one tongue causes the ejection of the other tongue. Once placed into use, this invention ensures that one of the tongues is latched.

Abstract: A buckle (20) comprises a base (80) which defines a cavity (88) for receiving first and second tongues (62, 64) of a vehicle seat belt system. A latch plate (102) is supported by the base (80) and is movable between a latched position connecting the first and second tongues (62, 64) with the base and a release position in which the first and second tongues are disconnected from the base. A pushbutton (222) is movable to an actuated position to move the latch plate (102) from the latched position to the release position. A spring (260) is located in the cavity (82) and is connected to the latch plate (102). The spring (260) has a portion (262) which urges the latch plate (102) toward the latched position. The spring (260) has another portion (264) which extends between the first and second tongues (62, 64) to urge the pushbutton (222) away from the actuated position.