Abstract: A power steering system having two or “dual” steering ratios is provided. The power steering system includes a transmission having first and second gear ratios, a steering gear coupled to the transmission, and a power assist coupled to the steering gear for providing power assist to the steering system. In one embodiment, the power steering system is configured to operate with a first steering ratio, such as a “fast” ratio, during normal operating conditions of the steering system (e.g., when power-assist is functional), and is configured to operate with a second steering ratio, such as a “slow” ratio, during abnormal operating conditions of the steering system (e.g., power-assist is non-functional, partially functional, etc.). The second steering ratio of the steering system can provide a fail safe mode for the vehicle operator so that the vehicle can be safely steered to a suitable location (e.g., side of the road, etc.) during abnormal operations conditions of the steering system.

Abstract: A diaphragm tensioning arrangement for a Sell-type ultrasonic transducer assembly is disclosed. The transducer includes a fixed backplate having a substantially planar electrically conductive front surface and a diaphragm having a front surface and back surface, the back surface of the diaphragm overlying the substantially planar surface of the backplate. The diaphragm includes an insulating layer adapted to contact the backplate and a conducting layer electrically isolated therefrom. The diaphragm tensioning arrangement includes means for applying a load to the front surface of the diaphragm in order to maintain diaphragm tension. A groove disposed in the backplate extension or base has at least one groove opening into its front surface. A tension element engages the front surface of the diaphragm pressing a portion thereof into the groove in order to maintain diaphragm tension.