GB1395927A - Signal generator - Google Patents

Abstract

1395927 Fluid oscillators JOHNSON SERVICE CO 28 July 1972 [29 July 1971] 35471/72 Heading G3H In a pulsating signal generating device, a pressurized fluid stream 4, Fig. 1, e.g. air, issuing from a nozzle 3 is partially impeded by a resilient or resiliently-mounted elongate member 10. The member extends perpendicularly with its axis laterally offset from the path of the stream, whereby the stream causes it to oscillate and generate a pulsating signal which is collected by a nozzle 6. Alternatively, the signal may be collected by detecting the movement of the member 10 by photo-electric means or the like. The member 10 is formed by a resilient tube 11, e.g. of spring stainless steel, and by a resilient rod 17, e.g. of spring steel, axially adjustably mounted within the tube to regulate the frequency of oscillation. Alternatively, the frequency may be varied by adjusting the mounting of the member, or the amplitude may be varied by controlling the supply pressure of the stream. In an alternative embodiment, Fig. 5 (not shown), a stream-impeding vertical rod (19) is hinged at its lower end and is biased into a stream-impeding position by a spring- loaded plunger (22) acting on its upper end. Alternatively, the stream impeding means may be constituted by two contiguous cantilevers slidable longitudinally relatively to each other.