Weldless pole mounting structure and method of providing same

Abstract

A hollow pole having a flared lower end is matingly mounted in a base flange fitted over, and in facing contact with, the flared end portion of the pole and having a tubular wedge matingly fitted in the flared end of the pole so that the pole is bonded to the tubular wedge and the base flange solely by galling action. The assembly is effected by using relatively soft aluminum alloy from which the components are made but which is heat treated prior to assembly to increase hardness and tensile strength so that assembly of the pole, tubular wedge and base flange results in a galling action providing the sole bonding of the pole to the other parts.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to the field of supports for vertically extending poles such as flag poles, light poles, signal poles, sign poles, antenna poles and the like, too numerous to list. More specifically, the invention relates to a new and unique apparatus and method which provide a stronger and more reliable structure at a reduced cost as compared to the prior art structures.

[0003] 2. Background of the Invention

[0004] Prior known pole mounting structures have employed a cast aluminum base provided by conventional casting procedures which initially produced a base having a conical shaped interior opening which is necessary in order to permit removal of the base from the mold. Since the bore of the base is intended to receive the end of a straight cylindrical tubing member, it has consequently been necessary to machine the conically shaped opening in the cast base into a straight cylindrical bore for permitting mating receipt of the end of the cylindrical tubing pole member which is then welded to the cast base. One of the advantages of the present invention is that it enables avoidance of both the machining of the conical shaped opening and the welding of the pole to the cast base so as to eliminate the cost of the machining and welding operations.

[0005] As was noted above, prior known aluminum pole mounting structures have employed welds for connecting and retaining the cylindrical aluminum end of the pole in the supporting cast aluminum base which had been previously machined to provide a cylindrical opening to receive the pole end. Unfortunately, use of welds to attach the pole member to the base dramatically decreases the allowable stress that may be imposed upon the pole and base assembly. A 1994 specification published by the American Association of State Highway and Transportation Officials entitled Standard Specifications for Structural Supports for Highway Signs, Luminaries and Traffic Signals recognizes the problems resultant from welded aluminum pole-to-base connections and indicates that the allowable stresses for welded connections is only 44% of the allowable stress for non-welded connections. It is therefore necessary for welded constructions to use larger and consequently more expensive pole and base members than would be necessary if welding was not employed.

[0006] More specifically, welding decreases the yield strength of the aluminum in the vicinity of the weld dramatically as evidenced by the fact that the tensile yield strength of aluminum alloy 6063-T6 is 25 kips per square inch for a non-welded connection and 11 kips per square inch for a welded connection which amounts to a 56% reduction in the yield strength when a welded connection is employed. However, it has been the practice in the industry to employ conventional tempering heat treatment of the welded pole and base after welding, which results in a weld connection in which the allowable stresses at best 15% less than the allowable stress for non-welded aluminum. The aforementioned heat treatment procedure for the welded base/pole assembly involves substantial time and expense which is greatly reduced by the present invention which eliminates welding altogether and which is of maximum strength (i.e., 15% greater than the welded structure which has been heat treated).

[0007] 3. Related Art

[0008] Other pole mounting assemblies have employed a variety of complicated structures which are expensive to fabricate and/or assemble and which in many instances fail to gain acceptance for a variety of reasons. Examples of prior art devices include: 1 Patent No. Granted Name Inventor(s) 43,998 30 Aug. 1864 Pipe Coupling S. C. Ketchum 187,394 13 Feb. 1877 Pipe-Couplings E. A. Leland 762,807 14 Jun. 1904 Ferrule for Boiler A. Cruise Tubes 764,088 5 Jul. 1904 Boiler Tube G, Wettels Fastening 969,216 6 Sep. 1910 Hose Coupling J. H. Stephens 1,388,657 23 Aug. 1921 Art of Joining H. P. MacDonald et al. Metal Parts 1,488,128 25 Mar. 1924 Junction of Metal H. P. MacDonald Parts and the Art of Joining Such Parts

[0009] Therefore, it is a primary object of the present invention to provide a new and improved pole support structure which is economical to fabricate and maintain.

[0010] Yet another object of the present invention is the provision of a new and improved aluminum pole and support structure which does not employ any welded connections.

[0011] Another object of the present invention is to provide a new, improved and simplified method of assembling and constructing a non-welded pole and base assembly of maximum strength.

[0012] Other objects, features and advantages of the present invention will be apparent to those skilled in the art upon a reading of this specification with reference to the accompanying drawings.

BRIEF SUMMARY OF THE INVENTION

[0013] A weldless pole assembly as provided in the first embodiment of this invention comprises an aluminum alloy pole having an outwardly flared lower end section of conical configuration which has been previously tempered following its machining to increase its strength. The inner surface that is flared outwardly downwardly is of conical configuration. The lower end of the pole member rests on an aluminum keeper plate which is supported by a foundation or footing or other conventional support such as a bridge component. An aluminum alloy tubular wedge, which has also been previously tempered following its fabrication by machining to increase its strength is of conical upwardly and outwardly flaring configuration and is matingly fitted within the confines of the flared lower end portion of the pole in face-to-face contact with the inner surface of the flared lower end portion of the pole. It should be understood that the directional words “downwardly” and “upwardly” are used in a relative sense with respect to the parts as shown in FIG. 1. The lower end of the tubular wedge is coplanar with the lower end of the pole and rests on the aluminum or steel keeper plate which in turn rests on a supporting foundation or the like.

[0014] A cast aluminum alloy base flange is formed of cast aluminum alloy 356-T6 by conventional casting procedures. The base flange includes a conical tube portion that is downwardly flared outwardly and a horizontal connector plate extending radially outward of the conical tube and which is matingly fitted about the exterior of the flared lower end surface of the pole with the inner surface of the conical tube facing and matingly contacting the outside surface of the flared lower end portion of the pole. The base flange and the tubular wedge also rest on the keeper plate, which is supported by a foundation or footing providing support for the entire assembly. The parts are arranged so that the lower end surface of the pole, the lower surface of the tubular wedge and the lower surface of the base flange all engage a planar upper surface of the keeper plate.

[0015] The first step in assembling the components consists of aligning the flared pole end with the wedge which is then matingly forced into the flared pole end. The base flange conical tube is then fitted over the pole shaft above the outwardly flared lower end portion of the pole and moved downwardly to snugly engage the outer surface of the flared pole end. The aforementioned downward movement of the base flange causes the flared pole end to be compressed between the inner surface of the conical tube of the base flange and the outer surface of the tubular wedge. A tight frictional bond between the inner surface of the base flange and the outwardly flaring pole portion is consequently effected, while simultaneously effecting substantial bonding between the outer surface of the tubular wedge and the inner surface of the outwardly flared pole portion. The pressure exerted by the tubular wedge and the base flange on the outwardly flaring lower end of the pole is substantial and causes galling which results in the bonding of the flared end of the pole with the base flange and the tubular wedge to provide a rigid pole assembly construction which can be attached to a foundation, footing or the like. The construction has greater strength than would be the case with a conventional welded construction.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The invention is better understood by reading the following Detailed Description of the Invention with reference to the accompanying drawing figures, in which like reference numerals refer to like elements throughout, and in which:

[0017] FIG. 1 illustrates a front elevation view of the preferred embodiment of the invention;

[0018] FIG. 2 illustrates a bisecting vertical section view of the preferred embodiment; and

[0019] FIG. 3 illustrates an exploded perspective view of the preferred embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0020] In describing preferred embodiments of the present invention illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.

[0021] The preferred embodiment of the present invention, which is generally designated 6, comprises an aluminum alloy pole 10, and an aluminum alloy base flange 12, an aluminum tubular wedge 14 of conical configuration and an aluminum or steel keeper plate 16. It should be understood that pole 10 can be used to support a variety of devices and is not limited to any particular type of support activity. For example, pole 10 can be a flag pole, a light support pole, an antenna support pole, a traffic light support pole or a pole supporting a multitude of other different types of devices.

[0022] Pole 10 and tubular wedge 14 are initially formed of relatively soft and easily worked aluminum alloy 6063 of T4 temper, which is purchased directly from the extrusion mill and worked as soon as possible since this alloy tends to harden with the passage of time. The aforementioned alloy is commonly referred to as 6063-T4 and has the mechanical and other properties as described on page 33 of the Aluminum Standards and Data 1990 (hereinafter “ASD”) published by the Aluminum Association, Inc. Pole 10 and tubular wedge 14 are tapered and flared by conventional equipment. Pole 10 and tubular wedge 14 are then subjected to heat treatment in conformity with page 56, ASD that converts them to higher strength tempered structure formed of aluminum alloy 6063-T6 in conformity with page 33, ASD. Base flange 12 is formed by casting aluminum alloy 356 and heat treating it to T6 temper. Keeper plate 16 is made of 6061-T6 aluminum alloy or steel such as ASTM A36.

[0023] Tempered pole 10 has an axis 11 and the lower end of the downwardly outwardly flared end portion 17 is concentric to axis 11 beginning in area 18 of the tempered pole and flares downwardly to the lower end surface 20 of tempered pole 10. Tempered pole 10 also has a downwardly outwardly flared inner surface 22 and an outer surface 24 which is also outwardly flared.

[0024] The tempered tubular wedge 14 has an upper end surface 26 which in the finished assembly is adjacent the upper end area 18 of flared portion 17 of tempered pole 10. Additionally, tempered tubular wedge 14 has a lower end surface 28 and an outer downwardly flared conical surface 30 of essentially the same shape and dimension as the downwardly outwardly flared inner surface 22 of the downwardly outwardly flared end portion 17 of tempered pole 10.

[0025] Tempered base flange 12 is a unitary cast structure comprising an outwardly extending conical tube 32, which flares downwardly and which has an inner surface 33 engaging the outer surface 24 of the flared portion of tempered pole 10. A connector plate 34 of thicker construction than tube 32 extends radially outward from the lower end of tube 32. Base flange 12 also has a lower surface 36 which is co-planar with the lower end surface 20 of tempered pole 10 and the lower end surface 28 of tempered tubular wedge 14.

[0026] The inner surface 33 of conical tube 32 is of essentially the same shape as the outer surface 24 of the flared lower portion 17 of tempered pole 10 so that surfaces 24 and 33 are in face-to-face contact. Four apertures 38 extend through connector plate 34 to permit the positioning of tie rods 40 or other conventional retainers which extend downwardly into a supporting foundation or footing 42. The threaded upper ends of tie rods 40 have washers 43 and nuts 44 for retaining the assembly in position on supporting foundation or footing 42. The exact nature and dimensions of the retainer will depend upon the nature of the particular pole and the supporting structure to or in which it is connected.

[0027] The structure is assembled by initially positioning and press fitting the tempered tubular wedge 14 in the flared portion 17 of tempered pole 10 following which the base flange is moved downwardly along pole 10 to press fit it on the pole in the position shown in FIGS. 1 and 2. The movement of the base flange into the FIG. 2 position causes the outer surface 30 of tempered tubular wedge 14 to forcefully engage the inner surface 22 of the flared tube portion while the outer surface 24 of the flared tube portion 17 is forcefully engaged with the inner surface 33 of conical tube 32. The downwardly outwardly flared lower end portion 17 of tempered pole 10 is consequently compressed between the surface 33 of conical tube component 32 and the outer surface 30 of tempered tubular wedge 14 with the pressure being sufficient to result in galling between the surfaces 22 and 30 and the surfaces 24 and 33. The galling of the face-to-face surfaces effects a strong bonding of the flared portion 17 to tempered tubular wedge 14 and tempered base flange 12. The fabrication of the pole assembly is consequently completed.

[0028] It should be understood that the above-discussed assembly procedures are not essential in order to provide a completed assembly. For example, the tempered base flange could be positioned over the flared portion 17 prior to insertion of tubular wedge 14 into the flared portion 17. Moreover, another option would be to position and press fit the tempered base flange and tubular wedge 14 in the pole simultaneously.

[0029] The completed pole assembly is mounted on footing 42 by aligning apertures 38 with apertures 39 of keeper plate 16 to permit positioning of the upper end of threaded tie rods or the like 40 in aligned apertures 38 and 39, which in turn permits positioning of washers 43 and nuts 44 on the threads of each rod. While not normally recommended, it is possible to eliminate usage of the keeper plate.

[0030] Modifications and variations of the above-described embodiments of the present invention are possible, as appreciated by those skilled in the art in light of the above teachings. For example, the cast components may in some instances be formed by machining, and machined components could in some instances be formed by casting. Also, some of the aluminum components could be formed of other metals, alloys or materials. It is therefore to be understood that, within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described.

Claims

1. A pole assembly comprising:

a hollow pole having a main axis, an inner surface, and an outer surface, and an outwardly flared hollow mounting portion concentric to the main axis, and having a lower end surface defining the lower extent of the pole member;

a tubular wedge positioned in the outwardly flared mounting portion and having a lower end surface, and an outer flared surface concentric to the main axis and in mating facing contact with the inner surface of the pole;

a base flange having an inner flared surface matingly fitted over and in facing contact with the outwardly flared mounting portion of the pole and having a lower end surface; and

wherein the lower end surface of the pole member, the lower end surface of the tubular wedge and the lower end surface of the base flange are coplanar surfaces.

2. A pole assembly as recited in claim 1, wherein the inner surface and the outer surface of the outwardly flared hollow mounting portion of the pole, the outwardly flared surface of the tubular wedge and the inner flared surface of the base flange are all conical surfaces.

3. A pole assembly as recited in claim 1, wherein said base flange comprises a unitary structure formed of a conical tube in which the inner flared surface of the base flange is provided, and a connector plate extending outwardly radially of the conical tube.

4. A pole assembly as recited in claim 3, wherein said base flange includes plural attachment permitting apertures in the connector plate for receiving retainers for connecting the pole assembly to a supporting foundation or footing.

5. A pole assembly as recited in claim 1, additionally including a keeper plate having an upper surface engaging the lower end surface of the pole, the tubular wedge and the base flange for permitting support of pole assembly by the keeper plate.

6. A pole assembly as recited in claim 5, wherein the inner surface and the outer surface of the outwardly flared hollow mounting portion of the pole, the outwardly flared surface of the tubular wedge and the inner flared surface of the base flange are all conical surfaces.

7. A pole assembly as recited in claim 6, wherein the base flange comprises a unitary structure including a conical tube in which the inner flared surface of the base flange is provided and a connector plate extending outwardly radially of the conical tube.

8. A pole assembly as recited in claim 7, wherein the base flange includes plural attachment permitting apertures in the connector plate for receiving retainers for connecting the pole assembly to a supporting foundation or footing.

9. A pole assembly as recited in claim 1, wherein the inner surface and the outer surface of the outwardly flared hollow mounting portion of the pole, the outwardly flared surface of the tubular wedge and the inner flared surface of the base flange are all conical surfaces; and

wherein the base flange comprises a unitary structure formed of a conical tube in which the inner flared surface of the base flange is provided and a connector plate extending outwardly radially of the conical tube and includes plural attachment permitting apertures for receiving retainers for connecting the pole assembly to a supporting foundation or footing.

10. A pole assembly as recited in claim 1, wherein the hollow pole is bonded to the tubular wedge and the base flange by galling contact with the tubular wedge and the base flange.

11. A pole assembly as recited in claim 10, wherein the inner surface and the outer surface of the outwardly flared hollow mounting portion of the pole, the outwardly flared surface of the tubular wedge and the inner flared surface of the base flange are all conical surfaces.

12. A pole assembly as recited in claim 10, wherein said base flange comprises a unitary structure formed of a conical tube in which the inner flared surface of the base flange is provided and a connector plate extending outwardly radially of the conical tube.

13. A pole assembly as recited in claim 12, wherein said base flange includes plural attachment permitting apertures in the connector plate for receiving retainers for connecting the pole assembly to a supporting foundation or footing.

14. A pole assembly as recited in claim 10, additionally including a keeper plate having an upper surface engaging the lower end surface of the pole, the tubular wedge and the base flange for permitting support of pole assembly by said keeper plate.

15. A pole assembly as recited in claim 14, wherein the inner surface and the outer surface of the outwardly flared hollow mounting portion of the pole, the outwardly flared surface of the tubular wedge and the inner flared surface of the base flange are all conical surfaces.

16. A pole assembly as recited in claim 1, wherein the hollow pole, tubular wedge and base flange are formed of aluminum alloy.

17. A pole assembly as recited in claim 16, wherein the inner surface and the outer surface of the outwardly flared hollow mounting portion of the pole, the outwardly flared surface of the tubular wedge and the inner flared surface of the base flange are all conical surfaces.

18. A pole assembly as recited in claim 16, wherein said base flange comprises a unitary structure formed of a conical tube in which the inner flared surface of the base flange is provided, and a connector plate extending outwardly radially of the conical tube.

19. A pole assembly as recited in claim 18, wherein said base flange includes plural attachment permitting apertures in the connector plate for receiving retainers for connecting the pole assembly to a supporting foundation or footing.

20. A pole assembly as recited in claim 19, additionally including a keeper plate having an upper surface engaging the lower end surface of the pole, the tubular wedge and the base flange for permitting support of pole assembly by the keeper plate.

21. A pole assembly as recited in claim 16, wherein the hollow pole, tubular wedge and base flange are formed of aluminum alloy 6063-T6.

22. A method of making a pole assembly comprising the steps of:

a) providing a tube, a tubular wedge and a base flange all of which are made of relatively soft aluminum machinable alloy having a relatively low tensile strength;

b) providing a flared end on the tube by machining one end of the tube to provide an outwardly flared end portion on the tube;

c) subjecting the flared tube, the tubular wedge and the base flange to heat to increase the tensile strength and hardness thereof;

d) matingly positioning the flared end portion of the tube over the tubular wedge with sufficient force to bond the tube to the wedge by galling; and

e) matingly positioning the base flange over the outer surface of the flared end portion of the tube with sufficient force to bond the tube to the base flange by galling.

23. The method of claim 22, wherein step d) is effected by contacting an inner conical surface of the outwardly flared end portion of the tube in face-to-face contact with a conical outer surface of the tubular wedge.

24. The method of claim 23, wherein step e) is effected by contacting an outer conical surface of the outwardly flared end portion of the tube in face-to-face relation with a conical inner surface of the base flange.

25. The method of claim 22, wherein the relatively soft aluminum alloy of step a) is 6063-T4 alloy and wherein the alloy resultant from step c) is 6063-T6 alloy.

26. The method of claim 25, wherein step d) is effected by contacting an inner conical surface of the outwardly flared end portion of the tube in face-to-face contact with a conical outer surface of the tubular wedge.

27. The method of claim 26, wherein step e) is effected by contacting an outer conical surface of the outwardly flared end portion of the tube in face-to-face relation with a conical inner surface of the base flange.