APPARATUS FOR MONITORING TRAFFIC

• US 3,849,784 A
• Filed: 11/14/1973
• Issued: 11/19/1974
• Est. Priority Date: 11/25/1972
• Status: Expired due to Term

• Current Assignee: Jurgen Holzapfel
• Original Assignee: Jurgen Holzapfel
• Inventors: Holzapfel, Jurgen
• Primary Examiner(s): Habecker, Thomas B.
• Application Number:
  US05/415,508
• Time in Patent Office: 370 Days
• Field of Search: 340/38R 346/17VP
• US Class Current: 396/318
• CPC Class Codes: G08G 1/0175 by photographing vehicles, e.g. when violating traffic rules
• CPC Class Codes: H05B 41/32 for single flash operation

Abstract

A traffic monitoring apparatus includes a camera and a photoflash unit to automatically take a picture of a vehicle illegally entering an intersection against a stop light. The camera simultaneously takes a picture of a time display device. One of the times indicated on that device is derived from an electronic digital counter. To ameliorate the problem of false counts in the counter caused by the opening of the switch which initiates the photoflash, a Zener diode and a capacitor are connected in parallel with that switch.

Claims

1. In an apparatus for monitoring the traffic at a road intersection at which there is a control light having a '"'"''"'"''"'"''"'"'stop'"'"''"'"''"'"''"'"' period, which apparatus includes:

a photographic camera actuated when a vehicle enters the intersection during said '"'"''"'"''"'"''"'"'stop'"'"''"'"''"'"''"'"' period, a time meter in the form of an electronic digital counter which receives counting pulses at a given frequency, a register having a control input and connected said digital counter so that the small time units are transferred to said register when a control impulse is applied to said control input at the beginning of the '"'"''"'"''"'"''"'"'stop'"'"''"'"''"'"''"'"' period, and a time display device connected to said register to display the time information stored in said register, said camera taking a photograph of both said road intersection and said time display device, the improvement comprising;

an electronic photoflash device comprising an electronic flash tube having a triggering electrode, A storage capacitor connected across said electronic flash tube for supplying the electric power to said flash tube to cause it to emit light, power supply means connected to said capacitor to charge it to an operating voltage, a triggering transformer having a primary and a secondary winding, the secondary winding being connected to the triggering electrode, triggering circuit means including a triggering capacitor and a triggering switch connected to the primary winding for energizing the transformer to initiate the discharge of the flash tube when said switch is closed, charging means connected to the triggering capacitor for charging the capacitor, and anti-interference means connected to the triggering circuit means for lessening the pulse occurring when said switch is opened to thereby ameliorate the occurrence of false counts in the electronic digital counter due to said pulse.

2. In an apparatus as claimed in claim 1, wherein said anti-interference means comprises voltage limiting means in shunt connection with said triggering switch.

3. In an apparatus as claimed in claim 2, wherein said voltage limiting means includes a Zener diode.

4. In an apparatus as claimed in claim 2, wherein said voltage limiting means includes a Zener diode and an ohmic resistor in series.

5. In an apparatus as claimed in claim 4 and further comprising an anti-interference capacitor also connected in shunt connection to said triggering switch.

6. In an apparatus as claimed in claim 1, and further comprising:

solenoid means for actuating said camera and causing an exposure to be made, film transport motor means automatically energized after each said exposure, and means for inhibiting the charging of said storage capacitor while either of said solenoid means or said film transport motor means are energized.

7. In an apparatus as claimed in claim 6, and further comprising:

a relay having a relay contact connected to said power supply means for disabling the power supply means from supplying power to said storage capacitor when said relay is energized, and means connected to the relay for energizing said relay and connected to said storage capacitor to energize said relay when said voltage exceeds a preselected value, said inhibiting means being connected to said relay energizing means to cause energization of said relay also in response to a signal indicating energization of either said solenoid means or said film transport motor means.

8. In an apparatus as claimed in claim 7, wherein said relay energizing means comprises:

a voltage divider connected across said storage capacitor and having a tap, a first transistor having a base, a Zener diode connected between said tap and said base, a Schmitt-trigger connected to the first transistor to be triggered by said first transistor becoming conductive, and a second transistor having a collector circuit and connected to said Schmitt-trigger to be rendered conductive by the triggering of said Schmitt-trigger, said relay being connected in the collector circuit of said second transistor, and wherein said inhibiting means comprises a third transistor having a base and an emitter-collector junction, said junction being connected in shunt connection to said first transistor and said base being connected to receive said energization indicating signal and rendering said third transistor conductive.