Roadway sensor with improved insulated signal carrying wires

• US 6,744,378 B1
• Filed: 09/01/2000
• Issued: 06/01/2004
• Est. Priority Date: 09/01/2000
• Status: Expired due to Fees

• Current Assignee: Polaroid Corporation (PLR IP Holdings LLC)
• Original Assignee: Traffic Monitoring Services Incorporated
• Inventors: Tyburski, Robert
• Primary Examiner(s): TONG, NINA C
• Application Number:
  US09/653,697
• Time in Patent Office: 1,369 Days
• Field of Search: 340/933, 340/937, 340/941, 340/935, 340/936, 340/938, 340/939, 340/940, 200/86.A, 200/85.R, 701/117, 701/118, 701/119, 324/236, 324/238, 324/244, 324/654, 324/655, 738/665
• US Class Current: 340/933
• CPC Class Codes: E01F 11/00 Road engineering aspects of Embedding pads or other sensitive devices in paving or other road surfaces , e.g. traffic detectors, vehicle-operated pressure-sensitive actuators, devices for monitoring atmospheric or road conditionspressure-sensitive elements G01L; traffic control systems G08G
• CPC Class Codes: G08G 1/02 using treadles built into the road pads or other sensitive devices responsive to passage of vehicles E01F11/00

Abstract

A vehicular roadway sensor comprising a conductive elastomeric housing having a sensor wire groove and one or more signal wire in the sensor wire groove, the sensor wire groove comprised of an airgap portion and a sensing wire portion for receiving and maintaining one or more insulated sensing wires in a fixed relation to establish a residual charge relationship with the conductive elastomeric housing so that when the fixed relationship is changed by the wheels of a vehicle on the housing a signal voltage is induced in the sensor, and one or more insulated signal carrying conductors connected to the one or more sensor wires, respectively. The one or more insulated signal carrying conductors are adhesively mounted in the conductive elastomeric housing so that vehicular traffic traversing the conductive elastomeric housing does not induce significant signals in the one or more insulated signal carrying conductors and wherein each insulated signal-carrying wire is covered with a rubber insulation so that minimal signals are generated in the signal-carrying conductors by heavy trucks thereby providing a high margin or tolerance for signal discrimination.

Claims

1. In a vehicular roadway sensor comprising a conductive elastomeric housing having a sensor wire groove and one or more signal wire in said sensor wire groove, said sensor wire groove comprised of an airgap portion and a sensing wire portion for receiving and maintaining one or more insulated sensing wires in a fixed relation to establish a residual charge relationship with said conductive elastomeric housing so that when said fixed relationship is changed by the wheels of a vehicle on said housing a signal voltage is induced in said sensor, and one or more insulated signal carrying conductors connected to said one or more sensor wires, respectively, the improvement comprising, said one or more insulated signal carrying conductors being mounted in said conductive elastomeric housing so that vehicular traffic traversing said conductive elastomeric housing does not induce significant signals in said one or more insulated signal carrying conductors and wherein each insulated signal-carrying wire is covered with a rubber insulation.

2. The roadway sensor defined in claim 1 wherein each said insulated signal-carrying wire is comprised of a stranded tinned wire having a cotton separator wrapping.

3. A multilane vehicular sensor comprising, for each lane, an impact sensing element comprising first unpolarized elongated dielectric, a first elongated conductive member, a second unpolarized elongated dielectric adjacent said first dielectric and a second conductive member adjacent said second dielectric, each said impact sensing element being characterized in that each has a length approximating the width of a lane and in that at least one of said dielectrics has a naturally occurring first residual charge adapted to gravitate toward an interface, said interface being disposed between a surface of one of the conductive members and said first dielectric having the naturally occurring first residual charge to thereby cause an interfacial polarization and a uniform static electric field to be generated between the conductive members, at least one of said conductive members being disposed for movement in said uniform static electric field to thereby cause a disturbance of said uniform static electric field and a signal pulse to be generated in response to movement of said at least one of said conductive members and disturbance of said uniform static electric field, and said impact sensing element having an insulated signal-carrying wire connected to the other one of said conductive members and adhesively mounted such that vehicles traversing said insulated signal-carrying wire does not induce significant signals in said insulated signal-carrying wire and wherein each insulated signal-carrying wire is covered with a rubber insulation.

4. The multilane roadway sensor defined in claim 3 wherein said at least one of said conductive members disposed for movement in said uniform static electric field is a conductive elastomeric extrusion having a passage for fixedly receiving each insulated signal-carrying wire, respectively.

5. The multilane roadway sensor defined in claim 4 wherein each insulated signal-carrying wire is adhesively retained in its respective passage by cyanoacrylate-type adhesive.

6. The multilane roadway sensor defined in claim 3 wherein each insulated signal-carrying wire is comprised of a stranded tinned wire having a cotton separator wrapping.