Restraint system for a school bus seat

Details Restraint system for a school bus seat Restraint system for a school bus seat

2000-12-11

2002-11-26

Barfield, Anthony D. (Department: 3636)

Chairs and seats

Crash seat

Force-absorbing means incorporated into back

C297S483000, C297S487000

Reexamination Certificate

active

06485098

ABSTRACT:

FIELD OF THE INVENTION
The present invention is in the field of seat belts used to provide a protective passenger environment.
DESCRIPTION OF THE PRIOR ART
Conventional seat belt systems combining a lap belt and an upper torso belt are well known. These three-point restraint systems are usually used with seats offering rigid support for the belts. As typically used in a vehicle, the three-point restraint system consists of single belt having its opposite ends mounted to a pair of retractors with a seat belt tongue connected to the belt intermediate to the belt ends. The tongue may be swung across the person and engaged with a buckle affixed to the seat thereby positioning one portion of the belt across the lap and another portion of the belt across the upper torso. In some systems, only one end of the belt is mounted to a retractor while the other end is anchored to the seat or vehicle. Seat belts are active restraint devices, requiring a passenger to actively engage the restraints for them to be effective.
School bus passenger seats usually do not employ active restraint safety devices, but instead rely on a passive restraint seat design. School bus passenger seats are built to specifications conforming to the safety standards set by the National Highway Traffic Safety Administration, DOT. These are codified as 49 C.F.R. Ch. V, .sctn. 571.222, Standard No. 222, and require that the seat back bend or deflect forward when a force is applied to the rear of the seat back. The code further specifies that 4000 W inch-pounds of energy must be absorbed within a maximum forward deflection of the seat back of 14 inches and 2800 W inch-pounds be absorbed within a maximum rearward deflection of the seat back of 10 inches where W represents the number of seating positions for which the seat is designed. 49 C.F.R., Ch. V, .sctn. 571.222, S5.1.3-5.1.4. The code specifies a passive restraint system, and does not require any sort of active restraints, such as a two-point passenger restraining lap belt or a three-point passenger restraining lap belt and torso harness combination. Children riding the school bus are protected in head-on collisions by the seat back in front of them deflecting forward and absorbing some of their forward momentum.
Vehicles with deforming or deflecting seats provide special problems regarding the integration of active restraint seat belt systems. Passive restraint systems are designed to protect a passenger who has been thrown forward by having the impacted seat back deflect upon impact of the thrown passenger and absorb some of their momentum. In a school bus seat combining active and passive restraint systems, both of the restraint systems have to be able to perform their functions and the seat must still conform to the regulations set forth in 49 C.F.R.
In U.S. Pat. No. 5,746,476, there is disclosed an automotive seat having a tower frame associated with the harness to transmit impact loads to the floor. Despite the prior devices, there is still a need for increased protection for children riding the school bus in an emergency or crash situation. The addition of an active restraint system, such as a three-point lap belt and torso harness combination, would provide enhanced passenger protection in a head-on crash as well as providing passenger protection in a broadside collision and/or roll situation. Disclosed herein is a three-point lap belt and torso harness passenger restraint system that is compatible with the pivoting and deflecting seats required by 49 C.F.R.
A further need is to provide a restraint system for a school bus seat that is operable to remove slack in the belt during rapid vehicle deceleration. The conventional method is to employ pretensioner devices connected to the belt which rapidly withdraw the belt once a pyrotechnic charge fires upon sensed vehicle deceleration. Such pretensioner devices may be mounted beneath the seat. In the case of a school bus seat, the addition of a pretensioner device reduces storage space beneath the seat. In lieu of a pretensioner device, we have devised a device built into the seat to automatically take up slack in the belt as the restrained passenger moves forward with the tower frame assembly during vehicle deceleration.
SUMMARY OF THE INVENTION
One embodiment of the present invention is a three-point lap belt and torso harness passenger restraint system for a school bus having forward-facing bench seats fastened to the vehicle floor and having forward pivoting and deflecting seat backs, comprising a lap belt and torso harness combination connected to a support structure positioned within the bench seat and coupled to the floor of the vehicle. The support structure includes a connecting member connected to the seat support and a tower member pivotally coupled to the seat support. The tower member includes a vertical slot that accepts one end of the connecting member, and both the tower member and the connecting members have coincident apertures through which a portion of the seat support may extend. The tower member lies in the plane of the seat back and is adapted to pivot through a predetermined angle around the rear of the seat support. The relative dimensions of the intersecting slot and connecting member determine the pivot angle.
In another embodiment of the present invention, a three-point lap belt and torso harness passenger restraint system for use with attached school bus seats having forward deflecting seat backs, comprises a three-point harness combination connected to a support structure coupled to the seat support and the vehicle. The support structure includes a connecting member connected to the seat support, a tower member connected to the connecting member and pivotally coupled to seat support, and a crossbar member connected to the front and rear portions of the seat support. The lower end of the tower member is connected to the connecting member, and the tower member is intermediately pivotally mounted to a seat support member. The tower member extends into the seat back and is adapted to pivot through a predetermined angle in response to a force acting thereon. As in the previous embodiment, a belt or harness system attached to the pivoting support structure allows a passenger to pivot forward sufficiently to allow the seat back to deflect according to specification, while holding the passenger in the seat.
In another embodiment of the present invention a restraint apparatus for a passenger in a vehicle having a seat frame mountable to the vehicle. The frame includes a seat portion and a back portion. The back portion has a bottom end portion, and a top end portion with the back portion pivotable forwardly about the bottom end portion toward the seat portion upon crash force applied to the back portion. A retractor has a web extending therefrom through a web guide. The web has a chest portion and a lap portion positionable across a passenger located on the seat portion. The retractor has an unlocked position and a locked position. A first lock is mounted to the web and a second lock is mounted adjacent to the seat portion and lockingly engaged with the first lock. A tower is mounted to the frame and movable with the back portion. A web tensioning arm is mounted to the frame and is moved by the tower to engage the web to take up slack in the web as the arm moves upon crash of the vehicle.
It is an object of the present invention to provide an active restraint system compatible with existing passive restraint school bus seats and the present Federal safety regulations.
A further object of the present invention is to provide an active restraint system for school bus passengers.


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