Transit vehicle door signal apparatus

Claim 1

An electronic signal apparatus for use in conjunction with the doors of transit vehicles to announce the door closings, comprising: a. a first and second switching means having input and output terminals, each adapted to be connected to a source of operating DC potential and each providing a DC voltage at each said output terminals for first and second periods of time respectively, in response to an intermittent DC voltage being coupled to said input terminals; b. first and second tone generator means each having input and output terminals for providing a first and second voltage at a predetermined frequency, respectively, at said output terminals; c. first and second means for providing a decaying DC voltage for said first and second periods of time respectively, said first means being coupled between said first switching means output terminal and said first tone generator means input terminal, said second means being coupled between said second switching means output terminal and said second tone generator means input terminal, d. time delay means having input and output terminals for providing a delayed DC voltage at said output terminal in response to a DC voltage at said input terminal, said time delay means input terminal being coupled to said first switching means output terminal and said time delay means output terminal being coupled to said second switching means input terminal; and e. utilization means coupled to the output terminals of said first and second tone generator means for providing a first and second audible tone for said first and second periods of time, respectively, said firSt and second audible tones being separated by a time interval equivalent to the time delay of said delayed DC voltage and said tone having a volume substantially decreasing in accordance with the amplitude of said decaying DC voltage.

Claim 10

The method of simulating an electro-mechanical chime for use in conjunction with the doors of transit vehicles to announce the door closing, comprising: a. providing first and second electronic tone generators capable of generating a fixed predetermined frequency output voltage through a change in operating voltage; b. activating a first switching means which couples said operating voltage to said first tone generator through a voltage decaying means; c. energizing a time delay means from said switching means; d. activating a second switching means which couples said operating voltage to said second tone generator, through a voltage decaying means from said time delay means; and e. combining said predetermined frequency output voltages in an audio amplifier and speaker means for providing first and second spaced audible tones decreasing in volume.

Claim 11

The method of simulating an electro-mechanical chime for use in conjunction with the doors of transit vehicles to announce the door closing, comprising: a. providing first and second electronic tone generators capable of generating a fixed predetermined frequency output voltage through a change in operating voltage; b. activating a first switching means which couples said operating voltage to said first tone generator through a voltage decaying means; c. energizing a time delay means from said switching means; d. activating a second switching means which couples said operating voltage to said second tone generator, through a voltage decaying means from said time delay means; and e. combining said predetermined frequency output voltages in an audio amplifier and speaker means for providing first and second spaced audible tones decreasing in volume.