Seat belt latch plate assembly

In a seat belt system with a continuous length of belt having an upper end mounted adjacent the occupant shoulder and a lower end mounted adjacent the occupant lap, and a latch plate assembly carried by the belt for engagement with a buckle, said latch plate assembly comprising:

• a housing having a tongue projecting from one end thereof for latching engagement by the buckle, a pair of flanges integral with the base wall and extending perpendicularly therefrom at a lateral spacing somewhat greater than the width of the belt, and a molded plastic cover having a depression extending laterally between the flanges;
• a lock bar pivotally mounted on the flanges by pivot pins extending from ends of the lock bar into openings provided in the flanges to define a pivot axis, said lock bar being a one-piece rectangular metal shape and having a clamping surface on one side edge thereof moving toward and away from the depression upon pivoting movement of the lock bar and having the belt wrapped around an opposite side edge opposite the one side edge so that a force applied to the belt pivots the lock bar and the clamping surface of the lock bar clamps the belt into the depression of the housing to lock the belt against movement through the latch plate assembly;
• the lock bar having the pivot axis closer to the one side edge of the lock bar having the clamping surface and further from the opposite side to provide a mechanical advantage which increases the clamping force on the belt;
• the lock bar being deformable and bending under the force applied to the opposite side edge of the lock bar, and the bending permitting the clamping surface of the lock bar to move further into the depression and increase the clamping force on the belt;
• and, a spring acting on the lock bar to pivot the lock bar to a normal position in which the clamping surface is moved away from clamping the belt into the depression so that the belt is allowed to freely transfer through the latch plate assembly when a force is not applied to the lock bar.