This invention relates generally to power seat adjusters and more specifically to power seat adjusters with an integral horizontal interlock system.
To maximize vehicle seat occupant comfort, it has been known in the art to provide power seat adjusters capable of adjustment in six directions. Typically the adjusters have a floor or lower channel fixably connected to the vehicle and an upper channel slideably mounted to the lower channel. An excellent example of a six way power seat adjuster can be found in U.S. Pat. No. 4,664,351 issued to Hans Borlinghaus and assigned to General Motors, the disclosure of which is incorporated by reference. Usually, the channels of a power seat adjuster are fabricated from extruded aluminum in an interlocking design. The fore and aft horizontal actuator of the seat adjuster is designed to withstand the normal loading imposed upon the seat due to sudden decelerations of the vehicle. However, the seat adjuster normally is not designed to withstand the loading of an occupant restraint belt system which can commonly be in the range of 6000 pounds of force. Therefore, the occupant restraint belt system is usually anchored directly to the vehicle floor.
When the vehicle seat belt is anchored directly to the vehicle floor, movement of the seat by the horizontal actuator can often require readjustment of the seat belt. It is desirable to provide a power seat adjuster and slide wherein the occupant seat restraint belt system may be anchored to the seat adjuster directly thereby deleting the requirement of the vehicle seat occupant having to adjust his vehicle seat restraint belt system every time he utilizes the seat adjuster. Examples of this can be found in U.S. Pat. No. 4,832,409 and U.S. Pat. No. 4,881,781 both issued to Hans Borlinghaus and commonly assigned to General Motors, the disclosures of which are incorporated by reference. These devices, though, have the difficulty of being complicated and expensive to manufacture.
Another example of the above described type of system can be found in U.S. Pat. No. 4,729,602 issued to Osamu Tokugawa. The Tokugawa device has the normal interlocking channels for normal fore and aft movement of the seat assembly. This device also has a occupant restraint belt system which is attached to a base plate. An anchor stay is fixedly attached to the body of the vehicle. A portion of the anchor stay contains a plurality of teeth, which in turn are covered by a resin cover. The base plate is positioned so that if a vertical force is applied to the occupant restraint belt system, the base plate will engage the teeth of the anchor stay. A pair of rivets hold the base plate in position so that the base plate does not engage the anchor stay prematurely.
One problem with the Tokugawa device is that it needs a vertical force to make it work properly. If the force of the occupant restraint belt system has no vertical component, or if the vertical component of the force is too small, the base plate will not engage the teeth of the anchor stay. For most sudden deceleration situations this will not be a problem. But some sudden deceleration situations could involve most of the force being directed in a horizontal direction, and the occupant restraint belt system may not have the necessary vertical force. Also, this device does not lock up immediately, but the base plate must travel to the next gap in the teeth of the anchor stay, adding to the time before the interlocking occurs. This design also necessitates adding extra pieces to the seat assembly, which adds cost and manufacturing difficulty.