Alcohol detection device

• US 4,607,719 A
• Filed: 12/19/1984
• Issued: 08/26/1986
• Est. Priority Date: 12/21/1983
• Status: Expired due to Fees

• Current Assignee: Drummond and Relph Limited
• Original Assignee: Drummond and Relph Limited
• Inventors: Drummond, Graham J., Rugis, John W.
• Primary Examiner(s): Love, John J.
• Assistant Examiner(s): Culbreth, Eric
• Application Number:
  US06/683,670
• Time in Patent Office: 615 Days
• Field of Search: 180/272, 180/271, 340/53, 340/576, 128/719, 128/724
• US Class Current: 180/272
• CPC Class Codes: B60K 28/063 preventing starting of vehicles

Abstract

An alcohol detection device for controlling the ignition circuit of a vehicle. The device incorporates an alcohol sensor (10) within an open ended body (21) to enhance evaporation of condensation within the body (21). Also mounted in the body (21) is a breath pressure operative switch (25) to operate in conjunction with the sensor (10). The outputs from the sensor (10) and the switch (25) are fed to an electronic latching circuit (19) controlling a short provided on a vehicle'"'"'s ignition circuit. An intending driver exhales into the body (21) a sufficient amount to activate the pressure switch (25) and in so doing provide a breath sample for the sensor (10). A time delay circuit (16) is preferably provided whereby the pressure switch (25) must be closed for a time period commensurate to that of the timer (16) to provide an output signal to the latching circuit (19).

Claims

1. A breath sample alcohol detection device comprising a body having openings at each of two opposite ends thereof and forming an interior chamber disposed between and terminating with the end openings, the portion of said body associated with a first of the end openings forming a mouthpiece and that opening conjoining directly with an inlet section of the interior chamber, the inlet section having a cross-sectional area substantially larger than the cross-sectional area of an output section of the interior chamber with the output section directly joining with the second end opening whereby an exhalation breath applied to the mouthpiece can create an increase in the fluid pressure within the inlet section of the interior chamber, a fluid pressure operative electrical switch mounted in an ante-chamber of the inlet section of the interior chamber and being sealiningly separated therefrom by a diaphragm, the pressure operative switch being set to actuate at a fluid pressure predetermined to be a pressure creatable by exhalation into the mouthpiece and an alcohol sensor having an electrically compatible output and being mounted in the inlet section of the interior chamber with the mounting suspending the sensor clear of the surrounding body.

2. A breath sample alcohol detection device and associated circuit comprising a body having openings at each of two opposite ends thereof and forming an interior chamber disposed between and terminating with the end openings, the portion of said body associated with a first of the end openings forming a mounthpiece and that opening conjoining directly with an inlet section of the interior chamber, the inlet section having a cross-sectional area substantially larger than the cross-sectional area of an output section of the interior chamber with the output section directly joining with the second end opening whereby an exhalation breath applied to the mouthpiece can create an increase in the fluid pressure within the inlet section of the interior chamber, a fluid pressure operative electrical switch mounted in an ante-chamber of the inlet section of the interior chamber and being sealingly separated therefrom by a diaphragm, the pressure operative switch being set to actuate at a fluid pressure predetermined to be a pressure creatable by exhalation into the mouthpiece and an alcohol sensor having an electrically compatible output and being mounted in the inlet section of the interior chamber with the mounting suspending the sensor clear of the surrounding body, the output of the sensor and the pressure operative switch providing separate inputs to comparator means, each input being coupled to a comparator associated therewith and each comparator also having an input at a pre-set level to thus provide a so referenced output, the comparator outputs being connected to from a control input to latching means adapted for connection into a vehicle ignition circuit, a time delay circuit connected to the control input to provide a delay between when a control signal, sufficient to activate the latching means or not, is first received by the latching means and the latching means response thereto thereby providing that the level of the output from the comparator coupled to the sensor existing at the end of the delay period is the output thereof that together with the output of the comparator associated with the pressure switch determines the control signal provided to the latching means, the circuit providing that if the sensor detects alcohol then the control signal will not effect operation of the latching means.

3. A breath sample alcohol detection device and associated circuit as claimed in claim 2 wherein a timer is incorporated into the circuit, an output of the timer and the common output of the comparators being connected as inputs to a third comparator forming the control input to the latching means whereby a time determined output of the timer will create a circuit operating state whereby the third comparator will maintain an operating signal to the latching means, the latching means comprising an SCR in series with a coil of a relay with the gate of the SCR forming the control input.

4. A vehicle ignition control circuit comprising an alcohol sensor and a fluid pressure operative switch providing separate inputs to comparator means, the sensor and pressure switch being mounted in a device providing a breath exhalation receiving chamber common to each whereby a breath sample monitored by the sensor must also generate sufficient pressure to operate the pressure switch to achieve the respective inputs, each input being coupled to a comparator associated therewith and each comparator also having an input at a pre-set level to thus provide a so referenced output, the comparator outputs being connected to form a control input to latching means connectable into a vehicle ignition circuit, a time delay circuit connected to the control input to provide a delay between when a control signal, sufficient to activate the latching means or not, is first received by the latching means and the latching means response thereto thereby providing that the level of the output from the comparator coupled to the sensor existing at the end of the delay period is the output thereof that together with the output of the comparator associated with the pressure switch determines the control signal provided to the latching means, the circuit providing that if the sensor detects alcohol then the control signal will not effect operation of the latching means.

5. A vehicle ignition control circuit as claimed in claim 4 wherein a timer is incorporated into the circuit, the output of the timer and the common output of the comparator being connected as inputs to a third comparator forming the control input to the latching means whereby a time determined output of the timer will create a circuit operating state whereby the third comparator will maintain an operating signal to the latching means, the latching means comprising an SCR in series with a coil of a relay with the gate of the SCR forming the control input.