High Strength Seat Back

The field of the present invention is that of vehicle seats, particularly for vehicle seats in the forward row seating of a multiple-seating-row vehicle.

Most of the design restraints associated with vehicle seating are primarily concerned with preventing the vehicle seat from going forward in a frontal impact crash. However, sometimes it is desirable to prevent the front row seat back from possibly going rearwardly. Presently, the main factor which prevents rearward movement of the seat back is the structural integrity of the seat. Preventing possible rearward motion of a seat is harder to obtain when utilizing a reclining seat wherein the seat back in normal operation is allowed to recline rearwardly.

To meet the above-noted challenge, the present invention in a preferred embodiment brings forth a vehicle seat with an auxiliary strut having a fixed pivotal connection with either the seat back or the seat bun and a lost motion pivotal connection with the other frame member. In situations where the vehicle encounters a rear impact, the lost motion pivotal attachment is latched, thereby causing both ends of the strut to have fixed pivotal axes with the seat back and the seat bun, thereby hindering any further rearward motion of the seat back. However, in normal operation, the strut allows movement of the seat back rearwardly with respect to the seat bun with virtually no interference.

FIG. 1 is a perspective view of a preferred embodiment of the present invention.

FIG. 2 is an enlarged view of the seat shown in FIG. 1 with a portion of the seat being removed for clarity of illustration.

FIG. 3 is a side perspective view of an alternative strut than that shown in FIG. 2.

Referring to FIGS. 1, 2 and 3, a preferred embodiment seat 7 according to the present invention is shown. The seat 7 has a second member seat back 2 which includes a generally inverted U-shaped seat back frame 4. The seat back frame 4 is pivotally connected with respect to a first member seat bun 6 frame 8 along a fixed pivotal axis by pins 10. To adjustably set the inclination of the seat back frame 4 with respect to the seat bun frame 8, there is a linear adjuster actuator 48 having an actuator 50 which is manually or power actuated and an end 62 which is pivotally connected by a pin 52 with the seat back frame 4.

A strut 12 is provided having a first upper rigid link 14 and a second rigid lower link 16. The strut 12 is typically hidden from view by cushion material also covering the seat back frames 4 and 8. In many instances, the strut 12 will be located on the inboard side of tile seat 7. Link 14 at its upper end is pivotally attached along a fixed pivotal axis with the seat back frame 4 by a pin 18. The upper link 14 is pivotally connected by a pin 20 with the lower link 16. A spring member 22 held in grips 24 of the upper and lower links and pressing against the pin 20 biases the links 14 and 16 into a bent position.

The lower link 16 has at its lower end fixably joined thereto a cross pin 26. The cross pin 26 rides in a linear groove 30 provided in a C-channel 28 and in a groove 64 provided within the bun frame 8. Underneath the cross pin 26 is a latch plate 32 having serrated recesses or indentions 38. The latch plate 32 has studs 34 (only one shown) which allow it to be pivotally mounted in apertures 36 (only one shown) in the C-channel 28. Underneath the latch 32 is a pendulum 42 of approximately 10 grams having a stem 44 connected with a button 46. The pendulum button 46 is supported on a platform 40 which is, in turn, suspended from the lower side of the C-channel 28.

During normal operation, a seat occupant via an actuator 50 will either extend or retract the actuator 48 to adjustably set the inclination of the seat back frame 4. During normal operation, the pin in the lower strut link 16 will freely slide within the oblong grooves 64 and 30. There will be virtually no effect upon the operation of the recliner mechanism by the strut 12.

In instances of a rapid forward acceleration of the vehicle in the range of 64 ft/sec.sup.2 (typically exceeded in a rear impact), the pendulum 42 will swing to the position shown in phantom. The pivoting of the pendulum 42 causes the button 46 to tilt and thereby lift up the bottom of the latch 32. Latch 32 will be actuated to pivot upwardly to the position shown in phantom until one of the indentions 38 surrounds the pin 26. At this point, the bottom link 16 will now have a fixed pivotal connection with the bun frame 8. Continued rearward motion of the seat back will be limited at the point where the upper link 14 and the lower link 16 are aligned straight with one another, making a three-sided truss with respect to pins 26, 18 and 10. When this point is reached, further rearward motion of the seat back frame 4 is greatly hindered and can only occur by elastic deformation of the strut 12 and/or the seat back frame 4 or the bun frame 8. The forward acceleration of the vehicle, which determines the actuation of the latch 32, can be set by setting the weight associated with the pendulum 42.

Referring to FIG. 3, an alternative preferred embodiment is shown wherein the strut 11 is a single curved member, rather than two separate links. This configuration may be found to be preferable since it is easy to hide the single strut member within the seat cushioning.

While this invention has been described in terms of a preferred embodiment thereof, it will be appreciated that other forms could readily be adapted by one skilled in the art. Accordingly, the scope of this invention is to be considered limited only by the following claims.