Abstract: A dual-face, internally-mounted cooling fan is provided in a dynamoelectric machine, e.g. an alternating current generator. The generator includes a ventilated housing supporting a stator assembly and a rotor assembly. The fan includes a divider disk having a plurality of blades provided on each surface and is mounted to rotate with the rotor assembly. As the fan is rotated, a plurality of separate air currents are drawn axially into the housing for cooling. The divider disk prohibits substantial mixing of currents drawn from opposite ends before they are radially expelled from the housing.

Abstract: A vacuum actuator, suitable for use in an automatic belt tensioning system, oscillates automatically when connected to a source of constant vacuum.

Abstract: A broadly tuned self resonant knock sensor includes a piezoelectric element mounted on a central mounting stud. The element includes a generally annular vibratable portion having a variable radial dimension so as to exhibit resonant vibrations at a plurality of relatively closely spaced resonant frequencies essentially spanning an engine determined knock frequency band. In its preferred embodiment the element comprises a circular plate having piezoelectric generating means and an axis offset from the axis of the mounting stud.

Abstract: A belt tension controlling mechanism has a spring member which operates on a pulley support bracket to establish a tension in a belt trained on the pulley. The spring member surrounds a threaded sleeve which is rotated by a pair of selectively operable one-way ratcheting clutches which are simultaneously driven in opposite directions by a vacuum motor. The rotation of the sleeve results in linear meovement of a shaft connected to the pulley support bracket to thereby increase or decrease the belt tension, depending upon which clutch is operable.

Abstract: A belt tensioner has a pair of pivotally mounted cam members which engage a stationary mounting strap. One cam is pivotally mounted on a block which is drivingly connected through a pivotal lever to a linear motor. The one cam is operative to engage a stationary strap when the motor is operated to urge the belt sheave bracket to pivot in a direction to increase the tension in the belt. When the one cam and block are moved by the return stroke of the motor, the other cam, which is mounted on the belt sheave bracket, engages the stationary strap to prevent movement of the belt sheave bracket relative to the strap.