This invention relates generally to the removal and/or replacement of wooden utility poles, light poles, sign poles or fence posts partially supported below ground level, and in particular, to a device for safely extracting a pole from the earth without damaging the pole or any surrounding structures.
As is known, utility companies supply the public with various products including electrical power, telephone service, and natural gas. Electric utilities are continuously in the process of upgrading their distribution system infrastructure in order to be able handle the increase in electric demand and to improve the reliability of existing services. This upgrade typically involves the replacement of old wooden utility poles (in some cases 80–90 year old poles) with new wooden utility poles that are engineered for the heavier conductor loads and tensions and that provide additional clearance for the higher distribution voltages. Road widening projects may also force the electric utilities to relocate their existing facilities, even though these facilities are not necessarily in need of repair. However, both of these situations usually require the removal of existing wooden utility poles.
On a typical road-widening project, the electric utility will install a plurality of new poles and string a new conductor along the edge of the new road right of way. Once this new line is energized and electric customers are transferred over to the line, the electric utility will remove the old wires from the existing line and cut the tops of the poles off just above the communications circuits (telephone and cable TV). This procedure allows the owners of communications circuits to lift their facilities over the top of the cutoff pole and transfer their facilities to the new poles without cutting and splicing. Once the remaining facilities are relocated, the remaining portions of the poles must be removed.
It has been found that a very high percentage of new utility poles that are installed on an annual basis are actually replacement poles. For a mid-sized electric utility, this can equate to the removal and replacement of over 10,000 poles per year. As such, a safe and economic means for removing the utility poles is a necessity. Heretofore, various types of the pole pulling devices have been utilized by the electric utilities. For example, U.S. Pat. Nos. 3,163,398 and 3,173,658 disclose commercially available pole pulling devices that include hydraulic cylinders and base plate assemblies that are coupled to corresponding poles via chains that cinch the poles.
While functional for their intended purpose, these prior pole pulling devices are cumbersome to operate and have numerous disadvantages. By way of example, for rear lot line applications, prior pole-pulling devices need to be carted by hand over to the pole and then assembled. A portable hydraulic unit also needs to be carted over to the pole. Further, the chain method of cinching the pole is not very effective. The chain tends to roll and not “bite” into the outer periphery of the pole as the cylinder is extended. As a result, a wedge block must be installed (i.e., driven in with a sledge hammer) between the chain and the pole to keep the chain from slipping. Once the hydraulic cylinder is fully extended, the wedge block needs to be driven back out (again, with a sledge hammer) and the cylinder must be retracted and reattached to the pole. Because of the limited stroke of the hydraulic cylinder (typically 18–24-inches), this operation can be time consuming and labor intensive. It is also noted that on soft ground, the base on the hydraulic cylinder of a prior pole pulling device can sink into the ground during extraction, leading to more operational problems. Finally, since the hydraulic cylinder is fixed to the pole, the mechanical forces applied to the pole and to the cylinder tend to tip the pole away from the side of the pole on which the hydraulic cylinder is attached. As a result, the top of the pole may tip in an unwanted direction.
In view of the above-mentioned operational difficulties that utility line mechanics encounter when using these prior pole pulling devices, alternate methods for extracting utility poles from the earth have been developed. A preferred method used by utility line mechanics is to loosen the pole by wiggling it back and forth with a digger derrick truck. Thereafter, a derrick winch line is used to extract the pole. Digger derrick trucks are not designed for this application and this operation can lead to damage to the crane boom and turret assembly of the truck. Safety is a major concern when exceeding the design limits of the boom truck.
Other attempts have been developed to address some of the issues heretofore described. U.S. Pat. No. 4,822,006 is directed to mechanism for reducing the slippage of the chain used to pull the pole from the earth. The mechanism utilizes mechanical fingers that dig into the pole as the hydraulic cylinders are extended. However, the design of the mechanism in the '006 patent raises a number of issues. For example, the variations in pole diameters and lack of concentricity can lead to gripping problems. Further, any side load on the mechanical fingers due to the cylinder not being centered can lead to bending of the cylinder rod resulting in an expensive repair. In addition, the mechanical fingers exert substantial inward pressure on the pole prior to extraction, thereby leading to the possible crushing of the wood without ever extracting the pole. Finally, the limited stroke of the hydraulic cylinder requires multiple strokes of the cylinder to fully extract a pole, thereby requiring a substantial amount of time.
U.S. Pat. No. 4,327,534 addresses the issue of extracting the pole in a single stroke by extending the length of the hydraulic cylinder. Although this approach will work, there are still chain gripping issues and longer hydraulic cylinder rods are susceptible to damage. There are also ergonomic issues associated with installing the device next to the pole.
U.S. Pat. No. 6,641,347 utilizes a design that is mounted to a piece of mobile construction equipment. While adequate for accessible locations, the design is not well suited for rear lot line applications. One positive feature is that the large surface area of the base plate keeps the design from sinking into soft ground. Further, the design places the mechanical forces to the ground rather than the piece of construction equipment. However, since the design is mounted in a bucket, it does not allow for the bucket to be utilized to fill the hole left by the extracted pole. In addition, other problems associated with the design disclosed in the '347 patent include ergonomic issues with having to physically rotate the hydraulic cylinder into position, the limited stroke capability of the hydraulic cylinder, chain slippage issues and the fact that the utility pole has a tendency to tip away as the pole is extracted.
Therefore, it is a primary object and feature of the present invention to provide a pole pulling device that will safely and efficiently extract a utility pole from the earth.
It is a further object and feature of the present invention to provide a pole pulling device that minimizes the ergonomic impact to the machine operator.
It is a still further object and feature of the present invention to provide a pole pulling device that has the ability to be mounted on a small compact utility tractor that can be used to transport the pole pulling apparatus and that utilizes the tractor as a hydraulic power source.
It is a still further object and feature of the present invention to provide a pole pulling device that incorporates a means to lay the utility pole down on the ground after extraction without the use of a digger derrick truck.
It is a still further object and feature of the present invention to provide a pole pulling device that is simple to operate and inexpensive to manufacture.
The drawings furnished herewith illustrate a preferred construction of the present invention in which the above advantages and features are clearly disclosed as well as others which will be readily understood from the following description of the illustrated embodiment.
In the drawings:
a is a cross-sectional view of the pole pulling device of the present invention taken along line 7a—7a of
Referring to
Referring to
Angled support member 40 extends between upper surface 18 of base 16 and outer wall 26b of support 26. In addition, angled support member 42 extends between upper surface 18 of base 16 and outer wall 28b of support 28. As best seen in
Upper ends 44 and 46 of supports 26 and 28, respectively, are interconnected by a generally tubular cross frame member 48. Guide wings 50 and 52 project laterally from corresponding ends 48a and 48b, respectively, of cross frame member 48 and define a recess therebetween for receiving pole 12, as hereinafter described. Pole pulling device 10 further includes first and second guide tracks 54 and 56, respectively, extending along inner walls 26a and 28a, respectively, of supports 26 and 28, respectively. Guide track 54 includes upper end 54a that abuts lower surface 58 of cross frame member 48 and lower end 54b vertically spaced from upper surface 18 of base 16. Guide track 54 is defined by generally flat inner guide wall 60 that lies in a plane generally parallel to inner wall 26a of support 26. Inner guide wall 60 of guide track 54 is spaced from and interconnected to inner wall 26a of support 26 by first and second sidewalls 62 and 64, respectively. Guide track 56 is defined by a generally flat inner guide wall 66 that lies in a plane generally parallel to inner wall 28a of support 28. Inner guide wall 66 of guide track 56 is interconnected to and spaced from inner wall 28a of support 28 by first and second sidewalls 68 and 70, respectively. As best seen in
As best seen in
Slider block 74 further includes recess 84 in upper end 86 thereof. Recess 84 is defined by recessed surface 88 spaced from upper end 86 of slider block 74 by sidewalls 90 and 92. Rotatable cable sheave 94 is mounted on an axle extending between sidewalls 90 and 92 of slider block 74 along an axis generally perpendicular to guide tracks 54 and 56. As is conventional, cable sheave 94 includes a circumferentially extending groove therein for accommodating cable choker 178 to travel thereon. Lower end 98 of slider block 74 includes a recess for accommodating terminal end of piston 102 of conventional hydraulic cylinder 104. It is contemplated to interconnect housing 106 of hydraulic cylinder 104 to the hydraulic power source of a utility tractor through line 49. As is known, piston 102 is movable between a retracted position,
Pole pulling device 10 further includes lower alignment mechanism 118 defined by central portion 120 having first and second alignment arms 122 and 124, respectively, diverging therefrom. Outer surface 122b of alignment arm 122 is affixed to lower end 126 of support 26. Similarly, outer surface 124 is interconnected to lower end 128 of support 28. As best seen in
Referring to
As described, with piston 138 of hydraulic cylinder 136 in its retracted position, first ends 132a and 134a of grappling arms 132 and 134, respectively, are separated so as to define passageway for pole 12 to be inserted between or removed from between grappling arms 132 and 134. As piston 138 of hydraulic cylinder 136 is extended, first ends 132a and 134a of grappling arms 132 and 134, respectively, move towards each other, and eventually overlap, so as to capture pole 12 therebetween. With piston 138 of hydraulic cylinder 138 of hydraulic 136 in its fully extended position,
In operation, pole pulling device 10 is interconnected to a compact utility tractor or other vehicle such as a pull behind trailer, skid loader or the like having an adaptable mount. Mounting point 41 is pivotably connected to the vehicle by hydraulic cylinder 170 and mounting points 43 and 45 are pivotably connected the vehicle by three point arms 172. With piston 138 in its retracted position,
With cable choker 178 interconnected to pole 12, piston 102 of hydraulic cylinder 104 is extended to its extended position,
With pole 12 fully extracted from ground 14, piston 138 of hydraulic cylinder 134 is moved to its fully extended position,
Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter that applicant regards as the invention.
Number | Name | Date | Kind |
---|---|---|---|
953234 | Rountree | Mar 1910 | A |
975832 | Clore | Nov 1910 | A |
2484400 | Brown | Oct 1949 | A |
2654630 | Renfroe | Oct 1953 | A |
3163398 | Eckels | Dec 1964 | A |
3173658 | Verrell et al. | Mar 1965 | A |
3233968 | Harvey et al. | Feb 1966 | A |
3239263 | Farmer et al. | Mar 1966 | A |
3647185 | Phibbs | Mar 1972 | A |
4082192 | Cox | Apr 1978 | A |
4256286 | Hudgins | Mar 1981 | A |
4327534 | Mastalski et al. | May 1982 | A |
4706935 | Thompson | Nov 1987 | A |
4822006 | McIntire | Apr 1989 | A |
4846445 | Pfeffer | Jul 1989 | A |
5195726 | Kaner | Mar 1993 | A |
5211374 | Head et al. | May 1993 | A |
5366338 | Mortensen | Nov 1994 | A |
5975826 | Scholder | Nov 1999 | A |
6056271 | Riojas | May 2000 | A |
6302380 | Ultimo, Sr. et al. | Oct 2001 | B1 |
6367779 | Martin et al. | Apr 2002 | B1 |
6382594 | Ransom | May 2002 | B1 |
6398188 | Salman | Jun 2002 | B1 |
6527250 | Tyson | Mar 2003 | B1 |
6598856 | Puff et al. | Jul 2003 | B1 |
6641347 | Ewington | Nov 2003 | B1 |
6669172 | Bearden | Dec 2003 | B1 |
20060027793 | Kysely | Feb 2006 | A1 |
Number | Date | Country | |
---|---|---|---|
20060027793 A1 | Feb 2006 | US |