Safety belt clamp apparatus, occupant restraint system and method

A force limiting safety restraint system for a seated occupant in a vehicle, said system having a safety belt passing over a shoulder of said occupant, said system comprising:

• a belt clamp apparatus wherein said safety belt is movable through said clamp apparatus in a first direction and in an opposite second direction, said clamp apparatus resisting movement of said belt in said first direction when a force above a first predetermined amount is applied to said belt in said first direction, said clamp apparatus including a lever pivotable on a first shaft, said lever having a clamping position and a non-clamping position, and a first biasing means biasing said lever to its non-clamping position, a clamp bar having a first surface for contacting a portion of said belt, a mounting means on said lever for movably mounting said bar on said lever, said mounting means comprising a channel in said lever, means for retaining said bar in said mounting means of said lever, said retaining means comprising lip means associated with said channel, said clamp bar being freely movable within said channel, and pivot means on a second surface of said clamp bar opposite from said first surface, said clamp bar being movable on said pivot means with respect to said lever for applying a substantially uniform force over an area of contact of said belt;
• and
• said belt clamp apparatus having controlled slippage means responsive to an unwinding force on said belt above a second predetermined amount resulting from a pull on said belt, said second predetermined amount being greater than said first predetermined amount, said controlled slippage means in response to said second predetermined amount of force allowing controlled slippage of said belt through said belt clamp apparatus;
• and
• a retractor mounted in said vehicle below said belt clamp apparatus, said retractor having belt-sensitive means responsive to movement of said belt in an unwinding direction above a third predetermined value resulting from a pull on said belt and preventing further unwinding of said belt means from said retractor, said third predetermined value being greater than said second predetermined value.

In a belt clamp apparatus wherein a safety belt is movable through said clamp apparatus in a first direction and in an opposite second direction, said clamp apparatus resisting movement of said belt in said first direction when a force above a first predetermined amount is applied to said belt in said first direction, said clamp apparatus including a lever pivotable on a first shaft, said lever having a clamping position and a non-clamping position, and a first biasing means biasing said lever to its non-clamping position, the improvement comprising:

• a clamp bar having a first surface for contacting a portion of said belt;
• a mounting means on said lever for movably mounting said bar on said lever, said mounting means comprising a channel in said lever;
• means for retaining said bar in said mounting means of said lever, said retaining means comprising lip means associated with said channel, said clamp bar being freely movable within said channel;
• and
• pivot means on a second surface of said clamp bar opposite from said first surface, said clamp bar being movable on said pivot means with respect to said lever for applying a substantially uniform force oveer an area of contact of said belt.

In a belt clamp apparatus wherein a safety belt is movable through said clamp apparatus in a first direction and in an opposite second direction, said clamp apparatus resisting movement of said belt in said first direction when a force above a first predetermined amount is applied to said belt in said first direction, said clamp apparatus including a lever pivotable on a first shaft, said lever having a clamping position and a non-clamping position, and a first biasing means biasing said lever to its non-clamping position, the improvement comprising:

• a clamp bar having a first surface for contacting a portion of said belt;
• a mounting means on said lever for movably mounting said bar on said lever;
• means for retaining said bar in said mounting means of said lever;
• said mounting means comprising a channel in said lever and said means for retaining said bar in said mounting means comprising a first lip on a first side of said channel and a second lip on a second side of said channel;
• and
• a crest on a second surface of said clamp bar opposite from said first surface, said clamp bar movable on said crest with respect to said lever for applying a substantially uniform force over an area of contact on said belt.

In a belt clamp apparatus for a vehicle occupant restraint system wherein a safety belt is movable through said clamp apparatus in an unwinding direction and in an opposite winding direction, said clamp apparatus resisting movement of said belt in said unwinding direction when a force above a predetermined magnitude is applied to said safety belt in said unwinding direction, said clamp apparatus including a lever pivotable on a first shaft, said lever having a clamping position and non-clamping position, and a biasing means biasing said lever in its non-clamping position, the improvement comprising:

• a resilient bushing means disposed around said first shaft;
• a clamp bar having a first surface for contacting a portion of said belt;
• a mounting means adjacent one end of said lever for movably mounting said bar on said lever, said mounting means comprising a channel in said lever, said bar disposed in said channel, a first lip on a first side of said channel and a second lip on a second side of said channel for retaining said bar is said channel;
• a crest on a second surface of said bar opposite from said first surface, said bar movable on said crest in said channel for applying a substantially uniform force over an area of contact on said belt;
• and
• a recess in said bar adjacent to said first lip;
• and a spring disposed in said recess between said bar and said first lip of said lever.