Improving Seat Belt Comfort on Off-Highway Vehicles

Occupant restraint system design for off-highway vehicles is examined from the standpoint of occupant comfort. Typical conditions of use for this class of vehicle subject the occupant, seat and restraint system to a wide range of occupant- and vehicle-induced movements both into and away from the seat belt. These types of movements in both static and retractable systems can create high seat belt loading and loss of comfort for the occupant. This loss of comfort may reduce the likelihood of seat belt use which will, in turn, reduce the overall effectiveness of the restraint system in the event of a collision or rollover. Solutions to this problem involve eliminating or counteracting the spring force of the retractor to reduce peak belt loads on the occupant. Several design solutions are examined for effectiveness in reducing occupant belt loads while maintaining overall safety.