TRANSIT VEHICLE DOOR SIGNAL APPARATUS

• US 3,744,022 A
• Filed: 12/30/1971
• Issued: 07/03/1973
• Est. Priority Date: 12/30/1971
• Status: Expired due to Term

• Current Assignee: Robert M. Olsen
• Original Assignee: Robert M. Olsen
• Inventors: Olsen, Robert M.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Swann, III, Glen R.
• Application Number:
  US05/214,273
• Time in Patent Office: 551 Days
• Field of Search: 340/52R,384E,274 180/111
• US Class Current: 340/425.5
• CPC Class Codes: B61D 19/026 Safety devices for preventing passengers from being injured by movements of doors or variations in air pressure safety devices in passenger lifts for preventing trapping of passengers between closing doors B66B13/26; acting on power-operated mechanisms for wings E05F15/00
• CPC Class Codes: G08B 3/10 using electric transmission; using electromagnetic transmission

Abstract

A signal apparatus for use with the moving doors of transit vehicles or the like and which preferably takes the form of an electronic door chime means simulating the tonal quality of electromechanical chimes by using an arrangement of solid state components and thereby eliminating the use of moving parts. The door chime means includes first and second switching means, first and second decaying network responding to the switching means and driving first and second tone generators, and a time delay means between the first and second switching means to sequentially trigger the tone generators.

Claims

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.

2. An apparatus according to claim 1 which further includes clamping means coupled to said input terminals of said first switching means for providing a DC voltage to said switching means input terminal after the cessation of said intermittent DC voltage, until said second audible tone has been completed.

3. An apparatus according to claim 1 wherein said first and second switching means comprises a transistorized monostable multivibrator.

4. An apparatus according to claim 1 wherein said first and second tone generator means comprises a transistorized phase shift oscillator.

5. An apparatus according to claim 1 wherein said first and second means for providing a decaying DC voltage comprises first, second and third resistors connected in series and a capacitor connected in parallel with one of said resistors.

6. An apparatus according to claim 1 wherein said time delay means comprises a unijunction transistor and resistor-capacitor timing circuit.

7. An apparatus according to claim 1 wherein said utilization means comprises a transistorized audio amplifier and loudspeaker system.

8. An apparatus according to claim 1 wherein said intermittent DC voltage is coupled to said first switching means input terminal in response to activation by a door closing means.

9. 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.