GB1464371A - Coin operated apparatus - Google Patents

Abstract

1464371 Coin operated apparatus R VERRILL and B M J VERRILL [trading as VERITRONICS] 29 Jan 1974 [29 Jan 1973] 4449/73 Heading G4U Coin-operated apparatus comprises a pair of parallel plates forming an electrical capacitance 4 through which a coin passes in use, means for measuring the change in capacitance caused by the coin and means for releasing a mechanism to enable it to operate if the change of capacitance falls with a predetermined range. A signal generator 2 generates a 100 Hz waveform which is applied to one plate of capacitor 4. A coin switches on the power supply by means of a micro-switch (not shown). A current amplifier 6 amplifies the square wave of current induced by the triangular voltage waveform. Rectifier 8 converts this signal to a D.C. proportioned to the capacitance 4 at its output. Output from the rectifier is fed to "upper limit" level detector 10 and "lower level limit" level detector 12. If these give a satisfactory signal, AND gate 14 is activated to transmit a signal to 10 ms. delay device 16 which gives an output only if the capacitance remains in the limits for 10 ms. This output is fed to a monostable 18 which gives a delay of 100 ms. when triggered. During the delay the circuitry is primed by causing diodes D1 and D2 to conduct and at the same time applying a fixed voltage to D1. At the end of the delay switch 20 is operated, which stays on for 30 ms. allowing a controlled amount of charge to flow into a 1 ÁF. timing capacitor 22 via diode D1. Thus each time a coin is detected the voltage on the capacitor is raised. A low frequency square wave oscillator 24 drives a 30 Ás. switch 26 which removes a controlled amount of charge from the timing capacitor once every 1À5 seconds. A meter 30 gives an indication of time left. Zero level detector 32 gives an output which switches off equipment such as tennis post solenoids at the end of the timed period. A 10 ms. delay 34 indicates an object has been present in the coin shoot for too long and operates a 60 s. switch 36 to discharge timing capacitor 22 and hold it "off" for one minute. The apparatus may be adapted to take coins of different denominations. Another application of the apparatus, apart from coin operated games, is in a parking meter.