Referring now to
In
The front frame 24 is mounted to a seat frame 26. The front frame 24 is also the attachment point for the upper portion of the passenger restraint 22, preferably a three-point seat belt. The seat frame 26 is mountable to the bus body mounting floor 14 and includes a rear frame 28. As shown in
Referring now to
Both the front frame 24 and the rear frame 28 preferably include cushioning for comfort and safety. In the preferred embodiment, an impact cushion 34 is located at the back side of the rear frame 28, and a middle cushion 36 is located at the front side of the rear frame 28 between the front frame 24 and rear frame.
At least one restraint retractor 38 is preferably attached to a lower portion 40 of the front frame 24 for extending and retracting the three-point belt 22. Preferably, the three-point belt 22 may also be attached to the front frame 24 at two other locations. In the preferred embodiment, the three-point belt 22 is attached at two locations on the lower portion 40 of the front frame 24, and at one location on the upper back resting portion 32 of the front frame. As is known in the art, the three-point belt 22 encircles the passenger 20 and is configured to secure the passenger's torso against the front frame 24.
The front frame 24 is mounted to the seat frame 26 at a guide channel 42. The guide channel 42 is preferably arranged generally horizontally and generally parallel to the mounting surface 14, and is configured to receive a guide member 44 attached to the front frame 24. The guide member 44 is preferably slidably engaged with the guide channel 42 and allows the front frame 24 to translate forward and rearward with respect to the seat frame 26.
An absorption device 46 mounted to the seat frame 26 preferably maintains the front frame 24 in position adjacent the rear frame 28 under normal stationary or driving conditions. In the preferred embodiment, each side of seat assembly 30 has a guide channel 42 with at least one guide member 44 engaged in the guide channel. Further, it is contemplated that the guide channel 42 may be located underneath the lower portion 40 of the front frame 24 on the seat frame 26. It is also contemplated that the front frame 24 may include the guide channel 42, and the seat frame 26 may include the guide member 44.
An upper portion 48 of the seat frame 26 is preferably located above the guide channel 42 and supports the rear frame 28. The rear frame 28 is pivotably mounted to the upper portion 48 at pivot point 50. A lip portion 52 of the rear frame 28 preferably engages a mechanical stop 54 on the seat frame 26 to prevent the pivoting of the rear frame 28 in the rearward direction (counterclockwise in Figures). The rear frame 28 is maintained in the generally upright position by the mechanical stop 54 and by the front frame 24.
As seen in
Under rapid deceleration conditions, the rearward passenger 18 seated behind the seat 16 impacts the rear frame 28 at the impact cushion 34. The force of the impacting passenger 18 causes the rear frame 28 to pivot forward with respect to the seat frame 26 at pivot point 50 (clockwise in the Figures). The amount of loading on the rear frame 28 to permit the rear frame to pivot may be a predetermined load amount. An impact force below the predetermined load amount will not result in pivoting, and an impact force above the predetermined load amount will result in pivoting of the rear frame 28. Under a sufficient loading, the rear frame 28 pivots forward and pushes the front frame 24 to translate forward. When the front frame 24 is translated forward, the rear frame 28 can absorb the impact loading from rear passenger 18 while moving the forward passenger 20 away from the location of impact. In this configuration, the forward passenger 20 is distanced from the location on the rear frame 28 where impact deformation may occur.
It is also contemplated that a sufficient impact loading will cause the front frame 24 to translate forward without the rear frame 28 pushing the front frame 24 forward. For example, the guide member 44 may be locked into position in the guide channel 42 with a lock 56 until the initial impact of the rearward passenger 18 on the rear frame 28 is sensed. This initial impact may be sensed when the lip portion 52 no longer contacts mechanical stop 54. When the initial impact is sensed, unlocking may be triggered by moving the lock 56 out of the path of the guide member 44. In turn, when the lock 56 is out of the path of the guide member 44, movement of the guide member in the guide channel 42 is permitted.
Further, it is contemplated that the front frame 24 may translate forward without being pushed or triggered by the rear frame 28. For example, the front frame 24 may translate solely due to deceleration forces acting on the front frame 24 and the passenger 20, where the deceleration forces overcome the absorption device 46.
The front frame 24 overcomes the absorption device 46 and translates forward in the guide channel 42 during rapid deceleration. The absorption device 46 is attached to the seat frame 26 at an absorption mount 58, and further, the absorption device is also attached to the front frame 24, preferably at the guide member 44. The absorption device, indicated generally at 46, preferably includes an absorption member 60, such as a mechanical spring, an air actuator or an air spring, a hydraulic actuator, a hydraulically linked spring, or any other member that is configured to maintain the front frame 24 in position adjacent the rear frame 28 under normal stationary or driving conditions. Additionally, a mechanism can be used to control the rate of the absorption, such as an air damper, hydraulic damper, or a magnetic damper. The absorption device 46 preferably controls both absorption of the loading and damping simultaneously. The absorption member 60 preferably links the absorption mount 58 to the guide member 44.
Under rapid deceleration conditions, the forces acting on the front frame 24 to translate the front frame in the forward direction overcome the force exerted by the absorption member 60. Under these circumstances, the guide member 44 moves in the forward direction within the guide channel 42, causing the front frame 24 to translate with respect to the seat frame 26, and causing the absorption device 46 to extend.
Referring now to
As seen in
While particular embodiments of the present seat assembly have been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.