Passive seat belt system

A passive seat belt system for automatic fastening or unfastening of a seat belt in response to the boarding or alighting of a vehicle occupant, comprising:

• overload detecting means for detecting the presence of an overload in the movement of a movable anchor of said seat belt, and
• control means for stopping a drive motor for said movable anchor in response to the detection of an overload in the movement of said movable anchor by said overload detecting means,
• said overload detecting means including rotation detecting means adapted to detect voltage changes generated at the change-over of connections of rotor coils of said motor between a commutator and brushes thereof for detecting rotation of said motor, and to identify an overload state when the frequency of said voltage changes becomes lower than a set value.

A passive seat belt system for automatic fastening or unfastening of a seat belt in response to the boarding or alighting of a vehicle occupant, comprising:

• overload detecting means for detecting the presence of an overload in the movement of a movable anchor of said seat belt, and
• control means for stopping a drive motor for said movable anchor in response to the detection of an overload in the movement of said movable anchor by said overload detecting means,
• said overload detecting means including rotation detecting means adapted to detect the rotation of said motor from one of an output shaft of said motor and a pulley for a drive member for said anchor of said seat belt, and to identify an overload state when the rotation of said motor becomes lower than a set value.

A passive seat belt system for automatic fastening or unfastening of a seat belt in response to the boarding or alighting of a vehicle occupant, comprising:

• overload detecting means for detecting the presence of an overload in the movement of a movable anchor of said seat belt, and
• control means for stopping a drive motor for said movable anchor in response to the detection of an overload in the movement of said movable anchor by said overload detecting means,
• said overload detecting means including torque detecting means for detecting the rotary torque of a pulley or said motor and identifying an overload state when said torque exceeds a set value.

A passive seat belt system for automatic fastening or unfastening of a seat belt in response to the boarding or alighting of a vehicle occupant, comprising:

• overload detecting means for detecting the presence of an overload in the movement of a movable anchor of said seat belt, and
• control means for stopping a drive motor for said movable anchor in response to the detection of an overload in the movement of said movable anchor by said overload detecting means,
• said overload detecting means including means for detecting one of movement and speed of a drive member for said movable anchor and identifying an overload state when said one of movement and speed of said drive member is less than a set value.

A passive seat belt system for automatic fastening or unfastening of a seat belt in response to the boarding or alighting of a vehicle occupant, comprising:

• overload detecting means for detecting the presence of an overload in the movement of a movable anchor of said seat belt, and
• control means for reversing and then stopping a drive motor for said movable anchor in response to the detection of an overload in the movement of said movable anchor by said overload detecting means,
• said overload detecting means comprising overcurrent detecting means, including converter means for converting the current in said motor into a voltage, set value determining means for determining a set value in dependence upon a power supply voltage, and comparator means for comparing the voltage from said converter means with a set voltage from said set value determining means and producing an overload signal when the voltage from said converter means exceeds said set voltage.