Abstract: A leaf spring for suspension of a rigid axle of a vehicle. The spring is joined at its first and second ends to a frame of a vehicle. The spring has a first portion extending from a first end to the junction with the axle in which the thickness of the spring increases along a parabolic curve from a first starting value at the first end to a first maximum value at the juncture with the axle, and a second portion which has a thickness which increases along a parabolic curve from the same first starting value at the second end to a second maximum value at the junction with the axle, the second maximum value being less than the first maximum value so that the stiffness of the first portion is greater than the stiffness of the second portion to such an extent that the radius of curvature of a path along which the axle is moving during flexing of the spring is increased by at least 5% compared to a corresponding spring having substantially the same first and second maximum values.

Abstract: A transport system installed in a cleanroom where clean air is caused to flow from a ceiling toward a floor. The transport system includes a vehicle for transporting loads, and a guide rail suspended from the ceiling to guide the vehicle. The vehicle has a main body for running along the guide rail, a load supporting deck disposed over the main body, and connecting members for interconnecting the main body and load supporting deck. The guide rail is enclosed in a tubular cover defining an opening extending longitudinally of the guide rail for receiving the connecting members. The cover has a substantially streamline configuration with respect to the direction of clean air flows.