Abstract: A manually adjustable apparatus for a zoom lens includes a body, a lens set, a sliding base, a rack sliding base, and a transmission gear. The lens set is installed at the body. There is an outer gear located at the rear end of the lens cone of the lens set. The sliding base is fastened at the body. On the bottom surface of the rack sliding base, there is a rack. The transmission gear is pivoted on the body and is interlocked with the rack and the outer gear. The present invention turns the rack sliding base manually to make the lens cone rotate and move via the rack, the transmission gear, and the outer gear for controlling and zooming the lens set. No power is needed so that the power loading of the still camera is reduced, and the cost of the still camera is reduced.

Abstract: An adjustable chair seat, of which the angle of the back frame, the seat width, and the seat depth may be adjusted; the arm rest assemblies can also be turned backwards at an angle of 120.degree.; the side frames can also be turned outwards at a horizontal position so as to provide a user with comfortable and convenient operation and use.

Abstract: A wheeled-chair chassis with a suspension mechanism which comprises a chassis structure, a suspension system, a transmission system and two front and rear wheels; the chassis structure includes a steel pipe frame similar to an inverse triangular frame. The suspension system includes shock absorbers, rocker arms, and pivot pins; one end of the rocker arm is connected with a pivot base on lower end of the steel pipe frame by means of a pin, while the other end thereof is mounted with a gear rack for mounting a motor of the transmission system, a gear box, and the rear wheels. The shock absorber is fixedly mounted between the steel pipe frame and the rocker arm to provide a retractable movement for absorbing a shake from the rear wheels and the rocker arm caused by a rough road surface in order to provide the chair with a comfortable driving. Since each of the systems is an independent assembly, it is easy to assemble.