Patent Application
20070044424
The present invention relates generally to the field of power poles for the support and travel of electrical conductor cables designed to transmit electrical power.
Electric transmission lines are the life-lines of a country's economy. Transmission lines interconnecting giant load centers with distant generation sources are vital to redistribute electrical power as required.
It is known to use treated wood poles to form transmission poles. However, chemicals used to treat wood poles have been found to contain carcinogens. Environmental and economic concerns stemming from the special disposal of treated wood poles have led to the search for alternatives to wood.
Concrete and steel are also used to form power poles. However, weight of these materials makes cost of transport and installation excessive. Moreover, steel is highly conductive, while concrete structures expand and contract with temperature causing vertical cracking.
Resistance to corrosion is an additional common concern when using power poles. The ground in which the pole is placed, as well as the surrounding environment, can cause the pole to corrode, decreasing pole strength and pole life.
Cost of power pole manufacture is an additional concern. This cost results from materials used, scrap, waste, time of manufacture, and labor. It is therefore desirable to provide a power pole that can be inexpensively manufactured and transported and that is environmentally safe while being resistant to corrosion and environmental factors such as wind, moisture, heat, cold, etc.
In an exemplary embodiment, a composite pole for supporting an electric transmission line is provided. The composite pole includes a plurality of interlocking outer panels forming an outer wall of the pole, and a plurality of interlocking inner panels forming an inner wall of the pole surrounded by the outer wall. The inner wall is interconnected with the outer wall forming the pole for supporting the electric transmission line. In one exemplary embodiment, the outer panels are formed from a first composite material and the inner panels are formed from a second composite material. The first and second composite materials may be the same materials and they may be non-conductive composite materials. In an exemplary embodiment, the composite materials include E-glass and a vinyl ester resin.
In another exemplary embodiment, the plurality of inner panels are identical. In a further exemplary embodiment, the plurality of outer panels are identical.
In yet another exemplary embodiment, the inner wall has a cross-section selected from the group of polygonal and circular cross-sections and the outer wall has a cross-section selected from the group of polygonal and circular cross-sections. In another exemplary embodiment, at least one of the inner and outer walls is tapered along its length.
In yet another exemplary embodiment, each inner wall panel interconnects with two other of the plurality of inner wall panels and with one of the plurality of outer wall panels. In yet a further exemplary embodiment, each outer wall panel interconnects with two other outer wall panels and with one inner wall panel. In one exemplary embodiment, the inner wall is interconnected with the outer wall by a plurality of ribs extending radially outward from the inner wall to the outer wall. In a further exemplary embodiment, each of the plurality of inner panels includes such a rib. In yet a further exemplary embodiment, each of the plurality of outer panels is interconnected with another of the plurality of outer panels via a first interconnection and with one of the plurality of inner panels via a second interconnection, such that the one of the plurality of inner panels is interconnected with another of the plurality of inner panels via a third interconnection, such that each interconnection is formed by one of the plurality of inner and outer panels being received in a slot formed in another of the plurality of inner and outer panels.
In another exemplary embodiment, a composite pole for supporting an electric transmission line is provided. The pole includes a plurality of identical interlocking outer panels forming an outer wall, and a plurality of identical interlocking inner panels forming an inner wall surrounded by the outer wall, such that each of the outer panels is interconnected with another outer panel and an inner panel and such that each of the inner panels is interconnected with an outer panel and another inner panel, and such that a rib extends from either each of the inner panels or each of the outer panels such that the ribs interconnect the inner wall to the outer wall forming the pole for supporting the electric transmission line. In an exemplary embodiment, the inner and outer panels are tapered such that the pole tapers from a base to a top, such that the pole base is wider than the pole top.
In yet another exemplary embodiment a method is provided for forming a composite pole for supporting an electric transmission line. The method includes extruding a first composite material through a first die forming a first extruded composite panel, cutting the first extruded composite panel as it is being extruded forming two identical outer panels, extruding a second composite material including a resin through a second die forming a second extruded composite panel, cutting the second composite panel as it is being extruded forming two identical inner panels, interconnecting the inner panels forming an inner pole wall, interconnecting the outer panels forming an outer pole wall, and interconnecting each of the inner panels to an outer panel. In an exemplary embodiment, cutting the extruded first composite panel includes placing a first blade proximate an exit of the first die such that as the first composite material is being extruded forming the first composite panel it is also cut by the first blade. Cutting the extruded second composite panel includes placing a second blade proximate an exit of the first die such that as the second composite material is being extruded forming the second composite panel it is also cut by the second blade.
In a further exemplary embodiment, the first composite panel exits the first die along a first path and the second composite panel exits the second die along a second path. The first blade travels along a third path generally perpendicular to the first path as the first composite panel is extruded cutting the first composite panel along a path oblique to the first path forming the two identical outer panels each having a tapered edge. The second blade travels along a fourth path generally perpendicular to the second path as the second composite panel is extruded cutting the second composite panel along a path oblique to the second path forming the two identical inner panels each having a tapered edge. In yet another exemplary embodiment, the method further includes routing the tapered edge of each of the outer panels as the outer panels are being extruded and routing the tapered edge of each of the inner panels as the inner panels are being extruded. In one exemplary embodiment, routing the tapered edges of the outer panels includes placing a first routing blade downstream of the first cutting blade such that the first routing blade simultaneously routes the tapered edges of both outer panels. In another exemplary embodiment, routing the tapered edges of the inner panels includes placing a second routing blade downstream of the second cutting blade such the second routing blade simultaneously routes the tapered edges of both inner panels.
Although not limited to a specific range, the height of the exemplary power pole assembly 10 is generally 45 to 120 feet. In one embodiment, the power pole assembly is composed of a non-conducting composite material, such as a composite of E-glass and a vinyl ester resin or other fiber reinforced resin composite materials. Such compositions are resistant to corrosion both from the environment and from the earth. As such, a portion of the base 16 of the power pole assembly 10 may be buried without risk of corrosion or rot.
The inner support ring 24 adds mechanical strength and assists in preventing local buckling of the power pole assembly 10. The inner support ring 24 defines a central opening into which additional hardware can be inserted and through which electrical and fiber optic cables can pass.
Each side wall panel 12 includes a side wall arm 25, a center panel connector 26 and a side wall connector 27 (see also detail A.) Each center panel connector 26 extends inwardly toward the inner support ring 24 of the power pole assembly 10, and includes two fingers having a gap therebetween for receiving the third arm 23 of one of the center panels 14 to form an interlocking connection therewith. In an exemplary embodiment, each side wall connector 27 includes two fingers having a gap therebetween and at least one ramp 28a on an inner surface thereof. Each ramp 28a receives a corresponding ramp 28b on an end of an adjacent side wall arm 25 to form a snap fit connection therewith. The snap fit connection is formed as the corresponding ramp 28b of the adjacent side wall arm 25 pushes outwardly on the fingers of the side wall connector 27. Once the corresponding ramp 28b of the adjacent side wall arm 25 advances into the gap a predetermined distance, i.e. when aligned with ramp 28a, the fingers of the side wall connector 27 have nothing pressing them outwardly. The fingers then snap inwardly and the ramp 28a on the inner surface of the side wall connector snaps over and mates with the corresponding ramp 28b of the adjacent side wall arm 25. In the exemplary embodiment of
When each of the plurality of side wall panels 12 is connected, the plurality of side wall arms 25 form an outer support polygon 29 of the power pole assembly 10. The side wall panels 12 are disposed in surrounding relation to the center panels 14. Such an arrangement allows for snap fit connections between the side wall panels 12 and/or the center panels 14. In an alternative exemplary embodiment, the outer support polygon 29 can have a circular structure wherein the side wall arm 25 of each side panel 12 is substantially curved. A top plate can be snapped onto a top surface of the power pole assembly 10 to prevent moisture from entering.
The structure of the power pole assembly 10 is relatively lightweight. Shipping weight of the power pole assembly 10 is 30 percent of that of traditional wood poles, and much less than steel or concrete poles. The inner support ring 24 increases the moment of inertia of the power pole assembly, which stiffens the pole and allows for better (less) deflection properties. In the shown exemplary embodiment, the outer support polygon 29 is formed of six side wall panels 12 and has six sides. In an alternative exemplary embodiment, the power pole assembly 10 may be formed of eight side wall panels 12 to form an outer support polygon 29 having eight sides. In other exemplary embodiments, the power pole assembly may be formed with more or less than six sides.
In an exemplary embodiment, the side wall panels 12 and the center panels 14 are manufactured via a pultrusion process, where the panels are extruded through a die assembly. With reference to
The cured panels exit the pultrusion machine at a speed which is measured by a wheel traveling with the pultruded panels. The cutting blade operates in conjunction with the traveling wheel, either mechanically or by computer program, to travel along the track to cut laterally across the moving pultruded member at a speed proportional to that of the pultruded member. Changes in pultrusion speed are detected directly or indirectly by the traveling wheel, and corresponding changes are made to the speed at which the cutting blade travels across the track to ensure a straight line cut.
The shape of the end of the side wall arm 25 can be formed on the tapered edge 30 by a high speed router, such that the two pieces formed from the cut can be assembled into one another as the tapered edge 30 of one of the cut side wall panels 25 fits into the side wall connector 27 of the other cut side wall panel 25. A routing blade, as for example a double sided routing blade, is placed in line with the cutting blade such that the two pultruded, cut members are routed by the routing blade along the tapered edge 30 to form the shape of the end of the side wall arm 25. In an exemplary embodiment, the routing blade sits six inches from the cutting blade, and is coupled to the cutting blade. The routing blade travels with the cutting blade laterally across the moving pultruded member(s).
In an alternative exemplary embodiment, the two side wall panels 12 are not cut at an angle from one another, and when assembled with other similarly shaped panels, form a power pole assembly that is substantially straight.
To form the tapered exemplary embodiment shown in
In an alternative exemplary embodiment, the two center panels are not cut at an angle to one another, and fit to form the inner support ring having a substantially straight shape. Any cutting and routing of the center panels 14 can be performed according to the exemplary embodiment outlined above.
The modular shape of the side wall panels 12 and the center panels 14 allow the panels to be stacked for ease of storage and transport.
In an alternative exemplary embodiment, at least one of the arms 21, 22, 23 of the center panel 14 can be formed as a separate member and assembled into the center panel 14. The connection can be achieved by the snap fit connection outlined above, or may also include an adhesive bond. In another alternative exemplary embodiment, the third arm 23 of the center panel 14 can be formed integral with the side panel 12, and may snap into the center panel 14, according to the snap fit connection outlined above, or may also include an adhesive bond.
In still another exemplary embodiment, a center panel 14 can be formed having two first arms 21, one being in place of the second arm 22. Center panels can be also be formed having two second arms 22, one being in place of the first arm 21. A center panel having two first arms can be connected to a center panel having two second arms, and the inner support ring can be formed by alternating the center panels having two first arms and the center panels having two second arms, the connections between the first and second arms being the same as described herein.
Although specific embodiments of the invention have been described above, the invention may have other variations as well. The present invention has only been described by way of exemplary embodiments. Specific descriptions are not intended as limitations of the invention. The current invention also covers other embodiments within the scope of the invention but not specifically described herein.
This application is based upon and claims priority on U.S. Provisional Application No. 60/705,522 filed on Aug. 3, 2005, the contents of which are fully incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60705522 | Aug 2005 | US |
