1. Field of the Invention
The present invention relates to manual seat adjusters for use in a motor vehicle or the like, and more particularly to manual seat adjusters of a type which is equipped with seat sliding, lifting and reclining mechanisms.
2. Description of the Prior Art
Hitherto, various types of manual seat adjusters have been proposed and put into practical use particularly in the field of wheeled motor vehicles. Some of them are of a type which is equipped with seat sliding, lifting and reclining mechanisms. The seat sliding mechanism is for adjusting a fore-and-aft position of the seat, the seat lifting mechanism is for adjusting the height of the seat, and the seat reclining mechansim is for adjusting the inclination angle of a seatback of the seat. However, due to their inherent constructions, some of the seat adjusters of such type fail to exhibit satisfactory performance. In fact, some of them suffer from the drawback that a very large driving force is needed to operate the seat lifting mechanism. Others suffer from the drawback that a considerable amount of play between parts tends to occur during operation of the seat reclining mechanism.