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 valve assembly having normally opened and normally closed valves controlled by solenoids to provide various connected and disconnected arrangements in a fluid system. It is particularly useful in a wheel lock control or anti-skid brake system (ABS).

Abstract: A knock sensor includes a circular mounting surface with a flat, self-resonant vibration element and piezoelectric disk coaxially mounted thereon. The vibration element comprises a central circular portion and a pair of outer semicircular portions of larger radius, the outer semicircular portions being shifted in opposite direction along their common border from the axis by an equal distances and each being divided into an equal number of sectors by radial slots centered on the axis and extending outward from the first radius with equal angles therebetween to from diametrically opposed pairs of similarly shaped and sized vibrating sectors. The pairs of sectors have resonant frequencies together forming a sensor passband wider than the individual passbands of the pairs taken separately. In addition, differences in resonant frequency between members of a pair due to misalignment of the axes of the vibration element and mounting surface do not significantly affect the sensor passband.

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.