Abstract: A ball joint including a socket defining a chamber and having an opening. The ball joint also includes a ball stud having a ball portion and a shank portion. The ball portion is located in the chamber of the socket. The shank portion of the ball stud projects through the opening in the socket. The chamber has a shape generally conforming to the shape of the ball portion of the ball stud. Electrorheological fluid is interposed between the ball portion of the ball stud and the socket for resisting relative movement between the ball stud and socket. The viscosity of the electrorheological fluid is variable as a function of the magnitude of an electric field applied thereto to vary the resistance to relative movement between the ball stud and the socket. The electric field applied to the electrorheological fluid is controlled to control the viscosity of the electrorheological fluid and thereby control the relative movement between the ball stud and the socket.

Abstract: A method and apparatus is disclosed for nullifying electrical offsets present in an output signal from a torsion sensing device. The apparatus includes a detection circuit for outputting an electrical signal when a change between a no applied torque condition and an applied torque condition occurs in a member whose torsion is being monitored. A sample and hold circuit measures the output signal from the torsion sensing device, the sample and hold circuit being triggered in response to the detection circuit. A differencing circuit subtracts the output of the sample and hold circuit from a "zero torque" reference value and outputs an electrical signal having a value indicative of the difference therebetween. An offset compensating circuit is electrically connected to the output of the differencing circuit and to the torsion sensing device and outputs a modified torsion sensing signal having a value that varies as a function of the applied torque offset by the value of the output of the differencing circuit.

Abstract: An auxiliary drive circuit is disclosed for an electric, power assist steering system including an actuatable switching device which, when actuated, provides an auxiliary electrical path between a source of electrical energy and a mechanically actuatable reversing switch assembly for applying electrical power to energize an electric assist motor. The actuatable switching device in the auxiliary drive circuit is electrically connected in parallel to an actuatable switching device in a main drive circuit. A detector circuit monitors the operation of the main drive circuit and the output signal from a torque sensor. Upon detection of applied steering torque greater than a predetermined value and that the main drive circuit is not operating, the detector circuit outputs an electrical signal indicative thereof. A latching element latches the output of the detector circuit to actuate the actuatable switching device in the auxiliary drive circuit.

Abstract: An apparatus for connection between relatively movable parts. The apparatus includes a variable volume chamber having a first portion for connection with one of the parts and a second portion for connection with another of the parts. The chamber has fluid therein for resisting movement of the parts relative to each other. A valve controls the fluid flow from the chamber to a location at which the fluid does not resist relative movement of the parts. The valve includes a valve member movable from a first position to provide fluid communication between the chamber and the location. An electroviscous fluid control device resists movement of the valve member form the first position.

Abstract: A power assist steering system in which electrical power to drive the electric assist motor is selectively provided from either the alternator or the battery depending upon the vehicle speed and applied steering torque. An electronic control unit controls the output voltage from the alternator by controlling current through the alternator field coil.