The present invention relates to an arrangement for mounting a restraint belt mounted vehicle seat to a vehicle floor and more particularly, to an arrangement for mounting a restraint belt mounted vehicle seat in an automotive vehicle that has an air bag system with multiple modes of inflation.
A typical automotive vehicle seat has a seat bun or cushion that supports the buttocks and upper thigh region of a seated occupant. Adjustably and pivotally connected to the seat cushion is a seat back. The seat back supports the back region of a seated occupant. The seat cushion is connected to a seat riser. To allow the seat to have fore and aft adjustment, a seat adjuster is provided. The seat adjuster includes a seat channel, also referred to as a seat rail. The seat rail is slidably mounted on a lower rail, often referred to as a floor rail. The floor rail is typically connected to the floor pan of the vehicle. Typically, the seat rail is interlocked along its length with the floor rail to prevent vertical separation. To ease the sliding movement between the seat rail and the floor rail, ball bearings or rollers spaced between the seat rail and floor rail are provided. The seat rail has a spring-biased locking mechanism that engages with a connected or integral rack provided on the floor rail to lock the relative fore and aft position between the seat rail and floor rail. Typically, the vehicle seat will have two parallel sets of floor rails and seat rails. A master floor rail and seat rail combination will have a master latch which manipulates a slave latch unit on a parallel spaced slave floor and seat rail assembly.
In the most recent quarter-century, to facilitate vehicle safety, seatbelts have been added to vehicles. As a further enhancement of vehicle safety, three-point seatbelts have been provided which include shoulder restraints. Most front seatbelts have one end anchored to a B-pillar of the vehicle. The belt extends downward across the torso of a seated occupant through a loop. From the loop, the belt is routed across the seat occupant""s lap and is then anchored to the vehicle floor. In a frontal crash, the load placed on the belt by a front seat occupant is mainly taken up by the B-pillar and/or the floor pan which the belt is anchored to.
In the most recent decade, a new type of anchoring system has been developed, commonly referred to as a belt-to-seat anchor restraint system. In the belt-to-seat anchor restraint system, one end of the belt is anchored to the B-pillar or to an upper region of the vehicle seat. The opposite extreme end of the belt is anchored to the upper portion of the seat riser which is fixably connected to the seat rail. The inner connection between the seat rail and the floor rail is strengthened to withstand the forces applied during a frontal crash situation.
Many vehicles on the road today have airbags installed in steering wheels, dashboards, and more recently, doors. These airbags are designed to protect a vehicle occupant against both front and side impact collisions by rapidly inflating the airbag to absorb much of the collision energy that would otherwise be transferred to the occupant.
Such conventional airbags are inflated based on a single threshold test: if a predetermined vehicle deceleration occurs in a collision, airbag inflation is triggered. Thereafter, airbag deployment occurs at a predetermined inflation rate. Both the triggering threshold and the inflation rate are typically not modified based on the type of vehicle collision, or the many different occupant variables, such as occupant weight, occupant position at the moment of impact, etc.
There has been a desire to modify air bag deployment based upon occupant weight and position. Typically, the larger the occupant, the greater the desired inflative force. For smaller occupants, a lowered inflative force response is desired.
There are two major approaches to determine occupant weight on a vehicle seat. One approach is to have a pressure sensitive pad or bladder mounted somewhere within the seat cushion. Another approach is to place weight sensors between the floor pan and floor rail to sense the weight distribution on the vehicle seat and at a predetermined time sequence, inform the seatbelt inflater controller of the weight placed upon the vehicle seat. When using the weight sensor system, a new problem has occurred. The weight sensor typically adds a fixed link between the vehicle floor pan and the floor rail. Although this link is typically very strong in compression, there are limitations of this link in tension. Some vehicle occupant weight sensor systems rely upon a cantilevered support arrangement between the floor rail and floor pan of the vehicle. Cantilevered support arrangement weight sensors are typically very weak in tension.
It is desirable to provide a seat mounting system which allows for the utilization of a weight sensor element spaced between the floor rail of the vehicle seat and the floor pan of the vehicle, while at the same time allowing the vehicle to utilize a belt restraint seat anchoring system that anchors the restraint belt to the seat.
In a preferred embodiment, the present invention brings forth an arrangement for mounting a restraint belt mounted vehicle seat to a floor of an automotive vehicle. The arrangement includes a floor rail that supports the vehicle seat typically by a fore and aft seat adjuster that includes an interlocking seat rail. A load cell provides a supporting platform for the floor rail above the vehicle floor. Connected to the floor rail is a force transmittal member.
In a preferred embodiment of the present invention, the force transmittal member has an aperture. Inserted through the aperture is a headed fastener that is connected to the vehicle floor. Additionally, a lower riser is provided which is connected to the floor rail via the load cell. The lower riser is connected to and held in position on the vehicle floor by the aforementioned fastener. The head of the fastener restrains a capture member and connects the capture member to the vehicle floor. In a preferred embodiment the capture member has a generally U-shaped cross-section with extending flanges. The capture member is positioned adjacent the aperture in the force transmittal member.
During normal operation, the compressive load of the vehicle seat is transmitted from the floor rail via the load cell to the lower riser and then to the vehicle floor. Upon a frontal crash situation, the floor rail will displace in an upward vertical motion and cause the force transmittal member to come into an interference situation with the capture member and thereby be retained to the vehicle floor. The floor rail will not be dependent upon the tensile strength of the load cell to return the vehicle seat to its position. The vehicle seat designer is now free to provide a load cell arrangement which can give sensory data to an air bag deployment system, while at the same time allow the vehicle seat to have a belt-to-seat mounting arrangement.
It is a feature of the present invention to provide an arrangement for mounting a restraint belt mounted vehicle seat to a floor of an automotive vehicle.
It is also a feature of the present invention to provide a method of retaining a vehicle seat to the floor of an automotive vehicle in a frontal crash situation wherein the vehicle seat utilizes load cells to sense the weight distribution upon the vehicle seat to inform a dual mode airbag inflation system.
Other features of the invention will become more apparent to those skilled in the art upon a reading of the following detailed description and upon reference to the drawings.