Other

James L Dennison

Douglas B MacDonald

An induction loop and a method of making an induction loop having conduit sections connected by a coupling assembly. The coupling assembly includes a passageway-defining body having ends for receiving sections of conduit. An intermediate body portion includes an opening exposing an intermediate passageway exteriorly. A lid for sealingly covering the opening includes an extension placeable into the opening for mating engagement with corresponding wall portions of the coupling body. The body and lid provide lateral external-pressure-withstanding structure to prevent damage to the assembled loop by absorbing regional pressures. This structure also provides for internal-pressure-withstanding sealing between the two so that, after completion of insertion of conductor in the conduit loop, the conduit may be injected under increased pressure with a heated rubberized asphalt sealant which is flexible at ambient conditions. Flexible joints in the form of short flexible conduit portions are inserted between the coupling body and the relatively rigid conduit section to permit angular displacement of the body relative to the section.

Conduit-enclosed induction loop for a vehicle detector

An induction loop vehicle detection system and method of making and installing such a system are disclosed wherein the conduit sections containing the induction loop are preformed and prewired integrally with all interconnects by using removable expansion joints to assemble sections of prewired and sealed conduit in any desired configuration. The expansion joints can be removed after assembly to enable the induction loop to be folded down for shipment. The expansion joints also enable longitudinal displacement of the induction loop conduit due to thermal differential expansion during installation and during extreme changes in temperature over the lifetime of the system, thereby preserving the integrity of the roadway and fault free operation of the induction loop. The wires forming the induction loop are completely sealed within the conduit with an asphalt rubber material thereby precluding any moisture penetration. The induction loop vehicle detector is installed by a method of dry routing of pavement which eliminates labor intensive slurry clean-up. The conduit is sealed in the routed slot in a roadway with a pressure withstanding asphalt rubber material which tenaciously adheres to the side surfaces of the routed slot.

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Los Gatos, CA, United States of America

James L Dennison