Abstract: A surface tracker includes a tubular marker body having an interior electronic marker and a visual indicator attached to an upper end of the marker body which extends away from the marker body. When deployed, the marker body is mostly underground and the visual indictor extends upwardly from the ground level to provide above-ground visual recognition. The electronic marker may be a passive electronic marker that includes a ferrite core assembly having a longitudinal axis which is generally parallel to a longitudinal axis of the marker body. The visual indicator may be a plurality of resilient filaments which pass through a hole in a tab portion of the marker body at the upper end thereof, the filaments being folded about the tab portion and secured to the tab portion using a heat-shrink tube. In an exemplary embodiment, the filaments extend about six inches from the marker body and are brightly colored. Multiple trackers can be used to mark the path of a buried utility.

Abstract: A method of joining two pipe ends, by forming male threads on an end of a first pipe with a steep taper angle, forming matching female threads on an end of a second pipe, and applying adhesive material to the threads before twisting the pipes to fully engage the male and female threads, thereby spreading the adhesive material across adjacent load-bearing surfaces of the threads. The threads have multiple start locations for thread engagement so that the pipe ends may be twisted to achieve full engagement in less than one full relative rotation. The male and female threads are formed with a squeeze angle between matching surfaces of the threads between 0.5 and 5.0 degrees. The finished joint provides immediate leak-tightness, and immediate tensile, compressive and torsional strength and does not protrude outside of the pipe profile.

Abstract: A surface tracker includes a tubular marker body having an interior electronic marker and a visual indicator attached to an upper end of the marker body which extends away from the marker body. When deployed, the marker body is mostly underground and the visual indictor extends upwardly from the ground level to provide above-ground visual recognition. The visual indicator may be a plurality of resilient filaments which pass through a hole in a tab portion of the marker body at the upper end thereof, the filaments being folded about the tab portion and secured to the tab portion using a heat-shrink tube. The visual indication, along with the ability to electronically detect the marker, provides a tracker with superior locating capability.

Abstract: A method of joining two pipe ends, by forming male threads on an end of a first pipe with a steep taper angle, forming matching female threads on an end of a second pipe, and applying adhesive material to the threads before twisting the pipes to fully engage the male and female threads, thereby spreading the adhesive material across adjacent load-bearing surfaces of the threads. The threads have multiple start locations for thread engagement so that the pipe ends may be twisted to achieve full engagement in less than one full relative rotation. The male and female threads are formed with a squeeze angle between matching surfaces of the threads between 0.5 and 5.0 degrees. The finished joint provides immediate leak-tightness, and immediate tensile, compressive and torsional strength and does not protrude outside of the pipe profile.

Abstract: A buried closure guard has an electronic transponder attached to a flat, perforated carrier sheet constructed of a flexible polymer. Holes in the carrier sheet, which serve to anchor the guard, preferably have an effective diameter of at least about 1½″ to allow typical backfill materials to pass through. By providing a webbed carrier, any protrusion of a digging tool (such as teeth on a backhoe bucket) will catch on one of these holes and pull at the carrier to make it further visible during excavation. The perforated construction of the sheet allows backfill material to settle and pass through the carrier without significantly shifting or bending the carrier. The carrier also makes it easy to manually deploy the transponder, i.e., maintain a proper horizontal orientation of the transponder coil.

Abstract: A buried closure guard has an electronic transponder attached to a flat, perforated carrier sheet constructed of a flexible polymer. Holes in the carrier sheet, which serve to anchor the guard, preferably have an effective diameter of at least about 1½″ to allow typical backfill materials to pass through. By providing a webbed carrier, any protrusion of a digging tool (such as teeth on a backhoe bucket) will catch on one of these holes and pull at the carrier to make it further visible during excavation. The perforated construction of the sheet allows backfill material to settle and pass through the carrier without significantly shifting or bending the carrier. The carrier also makes it easy to manually deploy the transponder, i.e., maintain a proper horizontal orientation of the transponder coil.

Abstract: A device for electronically marking a buried closure has a transponder and a shield or cover affixed to the transponder in such a manner that, when attached to the buried closure, the transponder is positioned at a predetermined location and orientation with respect to the known position and orientation of the buried closure. The shield can have a raised portion housing the transponder, and is preferably elongated with an arcuate cross-section, generally larger than the buried closure.

Abstract: A device for electronically marking a buried object, such as a service drop cable, comprising a reel for retaining the cable in a known position and orientation, and a transponder positioned at a predetermined location and orientation with respect to the cable wound on the reel. A foam shield may be used to provide a visual indication of the presence of the device, and an anchor may be affixed to the reel to secure it more firmly in the ground. The transponder can be located within the hub of the reel. The transponder can be active or passive.

Abstract: A transponder conduit end cap includes a transponder housing having two flat, generally parallel walls defining a cavity, a transponder located in the housing, and a fitting which attaches the transponder housing to the end of a conduit, to thereby seal the conduit. The transponder axis is maintained in a predetermined orientation (e.g., vertical), such as by partially filling the cavity with a liquid, and using a buoyant envelope to contain the transponder. Alternatively, the vertical orientation may be maintained by pivotally supporting the transponder from a trunnion attached to an interior of the housing. The transponder can be supported by the trunnion using a loop attached to an end of the transponder, the loop being placed about an annular chamfer of the trunnion to allow spherical articulation. The transponder can be active or passive.

Abstract: An article such as a conduit or cable, or a splice closure for a cable, is provided with improved resistance to animal damage by applying a layer of abrasive material to the article. The abrasive material is not only sufficiently hard and thick to act as a physical barrier, but its abrasive nature creates such a harsh, unpleasant grating effect that the animal tends to not attack it at all. The preferred embodiments of the article use either a plurality of granules to form the abrasive material, or a mesh substrate having an abrasive coating thereon. The material should have an effective grit value of no more than 325, and preferably no more than 100. The abrasive material may be applied using an adhesive or, where the conduit/closure is a thermoplastic polymer, various methods are provided for embedding the abrasive material in the polymeric wall.

Abstract: A marker tape for location of a buried conduit, having a plurality of electronic markers spaced thereon at predetermined intervals. The distance between the markers encodes information about the buried conduit. The tape may be a nonconductive ribbon or cord, and the markers are preferably passive circuits tuned to a specific frequency. The tape ribbon embodiment may include slots therein for receiving the markers. The markers may be oriented in a predetermined pattern to encode additional information.

Abstract: A marked conduit allowing electronic location of the conduit after burial, having a plurality of electronic markers spaced thereon at predetermined intervals. The distance between the markers encodes information about the buried conduit. The markers are preferably passive circuits tuned to a specific frequency. The markers may be oriented in a predetermined pattern to encode additional information, and may be attached to the outer or inner surface of the conduit, or imbedded in the wall of the conduit.

Abstract: A marker tape for location of a buried conduit, having a plurality of electronic markers spaced thereon at predetermined intervals. The distance between the markers encodes information about the buried conduit. The tape may be a nonconductive ribbon or cord, and the markers are preferably passive circuits tuned to a specific frequency. The tape ribbon embodiment may include slots therein for receiving the markers. The markers may be oriented in a predetermined pattern to encode additional information.

Abstract: An electrofusion marker which fuses two pipe sections together and acts as a passive electronic marker. The electrofusion marker includes a tubular thermoplastic fitting having a coil therein, which is temporarily energized by a power supply. This heats the fitting, causing it to fuse with the pipe sections. The coil doubles as an inductor, and a capacitor connected in parallel with the coil creates a resonant LC circuit. After the pipe sections have been fused together and buried the joint may be thereafter located by emitting a signal into the ground, which is picked up by the resonant circuit and re-radiated. The radiated signal is detected by a receiver, indicating location of the electrofusion marker and joint.

Abstract: A method and system for determining the location of a first insulated conductor and a plurality of similar branch conductors that are branches of the first conductor, but without ohmic contact being made with the first conductors. A passive marker having a resonant circuit that includes an inductor and capacitor is provided for each of the branch conductors and is positioned to be inductively coupled to the first conductor and the associated branch conductor. The first conductor is a part of a closed loop circuit and each branch conductor is a part of separate closed loop circuits. An alternating signal applied to any one of the closed loop circuits is inductively transmitted to each of the other closed loops that is inductively coupled to a passive marker having a resonant frequency equal to the frequency of the alternating signal.

Abstract: A marking tape that is positioned underground above utility lines wherein the marking tape carries a pair of closely spaced, parallel, insulated conductors that extend the length of the tape and at least one other insulated conductor extending the length of the tape which is separated from the pair of conductors at a distance that is greater than the distance between the conductors of the pair of conductors. Passive markers having a resonant circuit can be selectively placed along the tape wherein the resonant circuit is electromagnetically coupled to the pair of conductors and the other conductor. The other insulated conductor can be one of a pair of conductors similar to the other pair of conductors. A method is disclosed whereby the making tape can be electromagnetically traced with the position of the passive markers established. A method is also disclosed for determining the distance to a break in the tape which causes the pair of conductors to be severed.