Patent Grant
7246782
A. Field of the Invention
The present invention relates to bases or supports for vertically extending or elevating structures, and, in particular, to portable or temporary footings or bases for the same.
B. Problems in the Art
A wide variety of ways to support vertically extending structures have been developed over time. Special considerations come into play for structures that extend substantial distances vertically, and further, when the structures may experience forces that tend to tip the structures, such as wind.
Structure and stability issues become even more acute in situations where support for the vertical structure is desired to be portable or temporary. If the foundation or base cannot utilize any permanent footings in the ground, a primary source for providing stability to a vertical structure does not exist.
A few specific examples will illustrate this point. Situations exist where it would be desirous to have high-powered, wide area lighting, but on a temporary basis. The practical problems are, first, how does one transport such a system, especially when it is desirable to have the lights elevated to substantial distances vertically in the air; and second, how does one support and keep stable such elevated lighting fixtures through a variety of environmental conditions such as winds?
One situation where wide-area portable lighting is desired is with regard to construction sites. There are existing systems for temporary construction site lighting which tend to be on portable trailers or trucks. Lighting fixtures can be installed on foldable or extendible booms or frames. These types of conventional portable lighting units generally each require a separate vehicle to transport them from location to location. Also, they tend to be able to elevate the lights no more than perhaps 15′ to 35′. This does not allow for large area lighting. Additionally, because the lights are relatively close to the ground, glare problems can exist for workers and for traffic. Still further, many of these lighting systems are limited in height and number of lights, because of limitations of the base. Basically, existing systems tend to be no more than just a few light fixtures on a scaffold or foldable tower that does not extend very far into the air.
Some truck-based systems with larger, extendible booms exist. For example, U.S. Pat. Nos. 4,423,471, 4,712,167, 5,207,747, and 5,313,378 disclose high-powered lighting fixtures which can be extended much higher in the air (much over 30′) and are portable because they are mounted to trucks. However, such systems are expensive, both in original cost and operation, especially for areas such as constructions sites. Also, the trucks on which the fixtures are mounted would be out of use during the time the portable lighting was in use.
Therefore, a system has been developed which essentially consists of a transportable base that can be transported on conventional over-the-road trucks such as semi-trailers, can be manipulated by forklifts, and which can support a substantial sized light pole and array of light fixtures. Such a system is disclosed in commonly owned and co-pending U.S. Ser. No. 08/853,173. This system is relatively low-cost, can support a very tall vertical structure, and is portable. However, it is not adjustable in a variety of situations.
For example, such a base is pre-manufactured and fixed in perimeter size and in weight. It is also fixed in all dimensions and characteristics. If selected for a certain use, it may not be functional for another use. It may support a 50′ pole with five (5) 30″ diameter light fixtures in low-wind or no-wind conditions, but not be able to support the same in substantial winds.
Therefore, with regard to temporary lighting, there is a real need in the art for an improved system which provides more flexibility and adjustability over a wide variety of situations.
Similar problems exist with regard to supporting or elevating other types of structures. For example, there is a need for a more versatile and flexible footing or base-support for vertical towers, scaffolds, and trusses that are not needed on a permanent basis.
It is therefore a principal objective of the present invention to provide an apparatus and method for a temporary spread footing that solves or overcomes the problems or deficiencies in the art. Other objects, features, and advantages of the present invention include an apparatus and method for temporary spread footing that:
These and other objects, features, and advantages of the present invention will become more apparent with reference to the accompanying specification and claims.
The present invention includes an apparatus and method for a portable base or spread footing. The apparatus includes a frame-work that further includes a mount for a weight. The top of the frame-work includes a connection to which a structure can be removably attached. The top and bottom of the frame-work are spaced apart. A space or open area can be intentionally defined by the frame-work between the top and bottom into which can be placed one or more removable devices. The frame-work can also support a plurality of outriggers extendible from the base.
The method of the invention includes constructing a base frame with a substantial opening between top and bottom. The size of the base-frame is such that it can be transported in conventional, over-the-road vehicles. The structure to be elevated and supported is pre-evaluated. From the pre-evaluation, an appropriate amount of weight is added to the base frame-work and outriggers can be utilized to provide needed stability and resistance to overturning moment for the particular structure.
A variety of configurations can be created with the frame-work by interchangeable devices such as weights, on-board power generators, and other equipment. A variety of different structures can be supported and elevated to withstand various environmental factors such as wind.
A. Overview
For a better understanding of the invention, a preferred embodiment will now be described in detail. Frequent reference will be taken to the drawings. References numerals or letters will be used to indicate certain parts or locations in the drawings. The same reference numerals or letters will be used to indicate the same parts and locations throughout the drawings unless otherwise indicated.
B. Environment of the Preferred Embodiment
The Preferred embodiment will be discussed in the context of a portable, temporary base or spread footing to support a substantial length, vertically positioned pole, that supports a plurality of high-intensity, wide-area lighting fixtures. By substantial, it is meant that the poles are much longer than 20′ to 30′. The light fixtures are high-intensity arc lamps placed in bowl-shaped reflectors of approximately 2′ to 3′ in diameter. These types of fixtures are the same or similar to those that are conventionally used for outdoor sports lighting. An example of these lights are Musco Sports Lighting Model Sports Cluster II, Level VIII, or TLC available from Musco Sports Lighting, Inc., Oskaloosa, Iowa.
The environment and context of the preferred embodiment will also be with respect to the use of such lights for a construction site or similar lighting. The lights will therefore be outdoors and subject to the range of environmental conditions that may exist at any location, including winds of substantial velocity and varying ground and terrain topography and make-up.
It is to be understood that other analogous uses of lights of this nature are possible. It is also to be understood that other uses for supporting structures are possible with the base.
C. Apparatus of the Preferred Embodiment
Completing base 10 are two tubes 48 and two tubes 50 (in a cross shape) and side tubes 52 and 54. Each of the foregoing components of frame or base 10 can be welded or otherwise rigidly connected. Pieces 34 and 36 may or may not be tubular and are welded or otherwise attached into cut-out recesses in the tops of tubes 30 and 32. Similarly, cross-shaped tubes 48 and 50 can be welded into position in cut-outs in corner tubes 40, 42, 44, and 46, and converge to a central area at their opposite ends.
Vertical tubes 40, 42, 44, and 46 could be 6″ by 6″ steel tubing or 5″ by 5″.
The frame 10 therefore has outer dimensions that basically define a box. It is primarily made of tubing and has substantial open space between top 14 and bottom 12. Frame 10 is therefore strong but comparatively light. It cam be moved and transported relatively easily. The feet 64 at the ends of outriggers 16 can be positioned substantially away from the frame to greatly increase the overall “foot print” or lateral spread of base 10 on the ground and thus the resistance to overturning moment.
As illustrated in
Pole 20 could have a lower flange 82 which could be bolted to plate 18 by bolts 150 to form a 16″ bolt circle with 8¾″ bolts (See
In the preferred embodiment the following is a table of cross-sectional dimensions and thickness of certain of the parts:
Each of the tubing members of base 10 can be ASTM A500 Grade B steel structural tubing.
Following is a table of some other dimensions as indicated by the corresponding reference letters in the drawings (see particularly
Therefore
The space in base 10 could be used for storage. Examples are tool box(es), job box(es), parts, tools, generators, electrical components, or other components associated with what might be elevated on the pole.
On the other hand, top 14 of base 10 extends a substantial distance above the bottom of base 10 and provides, in perimeter dimensions, a fairly large platform area upon which a structure can be mounted.
Outriggers 16 allow the diameter of base 10 to be almost doubled in size with a corresponding substantial increase in the resistance to overturning moment, as opposed to just base 10 itself. Jacks 60 can be any of a wide variety of devices, but in the preferred embodiment can be trailer jacks manually operated. An example of jack 60 is Bulldog 10,000-lb capacity Top Wind Heavy Duty Trailer Jack. Other types are possible.
Pole 20 can be of various lengths. One possible range of lengths would be 40′ to 80′. The number of fixtures of the array 80 can vary, but usually would be anywhere from one (1) to twelve (12) fixtures. The object depicted in ghost lines by reference numeral 84, is intended to represent a device that can be placed into the space between top 14 and bottom 12 of base 10. In this example, device 84 could be an electrical power generator (self-contained, diesel powered) that could be removably positioned into base 10 and serve to operate lighting fixture array 80. Ghost lines 86 are intended to represent another device that could be placed into base 10 such as ballasts for the light fixtures or other electronic or electrical components used in the operation of array 80. It is to be noted and understood that such things as an electrical power generator is of substantial weight and could also act as an additional weight to assist in resistance of overturning moment and stability of base 10.
In operation the invention works as follows. Base 10 would be pre-constructed. As mentioned, it is of a size that could be transported to a site by convention over-the-road transportation. Prior consideration would be made of the specific structure with which base 10 will be used. Sufficient weight in the form of, for example, of concrete 22, additional weight 70, or devices 84 and 86 would be sent along with base 10, or available at the site.
Once at the site, base 10 could be manipulated by forklifts and other equipment to be placed in position on the ground or whatever other supporting surface is desired. Pre-determined add-ons such as weight or other devices or components would then be added to and attached to base 10. Outriggers 16 would then be extended and feet 64 brought into contact with the ground. The jacks 60 would be adjusted to bring base 10 off the ground, usually to a level orientation. The base would then finally be configured appropriately based on the device to be supported, and then the device to be supported would be mounted onto the top of base 10. In the foregoing example, a crane or some sort of a lifter device would raise pole 20 and array 80 vertically, move it over to above base 10, and then bring it down and mount it to the top of base 10. Any fine-tuning adjustment could be made, even after the structure to be supported (here pole 20 and array 80) is attached to base 10.
In this example, a generator 84 is added into base 10. The appropriate electric wires (in this example, pre-wired from array 80 down to the bottom of pole 20) could simply be electrically connected accordingly and the lighting array 80 could then be operated. It would be a self-contained lighting unit. The outriggers and weight in base 10 would have a pre-determined level of overturning moment resistance to handle whatever environmental standards exist for the site. This would include for certain configurations, winds on the order of 60 mph, or greater.
The apparatus operates on the physical principle that
Σμ=0 or (static equilibrium)=FL−WX
where μ is the sum of the moments, F represents the forces acting on the pole in a direction, L is the vertical distance from the top of the structure being supported to the ground, W is the total weight of the system, and X is the radius of Circle M, pictured in
The main variable is F, which is primarily wind loading. One can solve for any of the variables. Therefore, for any assumed wind load F, and any assumed outrigger extension X, the weight W needed to prevent overturning can be determined. Or for a given total weight, the length of outrigger can be determined.
The wind moment number is calculated based on standard building and structural codes for a particular configuration. Dividing the wind moment by the base moment arm results in the weight of the unit required to resist overturning. Since the operator or technician knows (a) the weight of his unit, (b) the fixture mounting height, (c) the number of fixtures, and (d) the EPA of the fixtures, he can determine from the charts what wind speed can be sustained based on his minimum moment arm (or outrigger) setting.
A booklet of charts can be produced which provides an operator with the information needed to set up the configuration to withstand certain winds. The charts would allow the operator to set the extension lengths of the outriggers and/or the amount of weight of the whole combination to meet the selected overturning resistance. The total weight would include the weight of everything associated with the base 10, including the pole, the fixtures, the mounts for the fixtures, the fixture control mechanisms, electrical and electronic components, as well as the base 10 itself and anything inserted into the base 10. For example, a 60′ tall pole can weigh 720 lbs., six (6) fixtures can weigh 150 lbs., controls and electrical components add 420 lbs. Base 10 can weigh on the order of 2,000-3,000 lbs. An electrical generator placed in base 10 could weigh on the order of 1,600 lbs. If outriggers are added, they could add 600 lbs. Then, if concrete add-on weights are added, they could add 7,200 lbs. to the total weight. See
The included preferred embodiment is given by way of example only and not limitation. Variations obvious to those skilled in the art are included within the invention which is solely described by the claims herein.
D. Options, Features and Alternatives
Another method of use of bases 10 would be a plurality of bases 10 to support a larger structure such as shown in
As has previously been discussed, the intentional creation of openings or space between the top and bottom of the base 10 allows for any variety of interchangeable and removable inserts. They can be functioning components or simply weight.
With regard to weights 22 and 70, it has been shown that a concrete block having steel facings on edges could be used. Alternatively, concrete with internal steel reinforcement like re-bar or re-rod could be used.
It could also be appreciated that weights such as weight 22 and weight 70 are inserted or recessed inside the perimeter of frame 10 so that they are inside the boundary of the overturning moment resistance. It also makes the weight closer to the center of the structure to make it easier for a forklift to lift and move the entire unit. This could occur with weights 22 and 70 attached to base 10 and even when a structure, such as a pole and light arrays is attached to base 10.
Another option would be to add a running gear to base 10 so that it could be pulled like a trailer. On the other hand, as discussed, bases 10 can be placed in conventional over-the-road transportation and could even be stacked on one another or nested somehow. Slots such as slots 25 or hooks (see 71 in
Dog 160 and slots 164 and 166 cooperate to require that arm 56 be pulled out into and inserted from tube 48 or 50 first, that is relative to arm 58. When arms 56 and 58 are fully extended, as shown in
Conversely, when arms 56 and 58 are retracted into tube 48, because dog 160 extends through slots 164 and 166, it requires that both arms 58 and 56 move out from tube 48 if either are pulled in that direction, until dog 160 clears tube 48, at which point dog 160 would pivot up and allow arm 58 to retract from arm 56.
Set-screws 172 and 174 in the side of arm 56 mate into cut-outs 176 and 178 in tube 48 when arm 56 is fully retracted into tube 48 and serve to disallow further inward movement of arm 56. Set-screws 176 and 178 are also used to deter rattles between tubes 48/50 and arms 56 and 58 once positioned in place. Set-screws 180 and 182 in tube 48 also serve to deter arms 56 or 58 from moving once positioned. Arms 56 and 58 are disallowed from being completely pulled out and separating from its succeeding part by set-screws, but can be pulled completely out if needed for maintenance or replacement.
Further, a pre-determined system for installing base 10 relative to different structures it supports and environmental conditions could optionally be created. For example, through empirical testing, a chart could be created for poles of varying heights with varying numbers of light fixtures. The chart would indicate how much weight should be contained on base 10 and how far outriggers 16 should be extended to provide the appropriate resistance to overturning moment. It would also include the amount of necessary resistance to overturning moment based on an anticipated range of wind velocities. With this chart it would allow the installer and user of the system to configure base 10 to meet or exceed the needs for a particular use without having to do independent testing and without substantial over-compensating with regard to weight and extension of outriggers.
A leveling device or devices could be added to base 10. In one simplistic form, level bubbles such as are used with carpenters' levels could be placed around the perimeter of base 10. The operator could visually see when base 10 is leveled.
Operation of adjustable jacks 59 could enable the leveling. Note that jacks 59 could be manually vertically adjustable. Alternatively, as shown in
Foot 64 could be 2′ by 2′ to diminish soil compaction.
For example, a chart (e.g.
There are times when the desired placement of the invention does not allow full extension of the outriggers. An example would be if the invention needed to be positioned next to a fence or building. Even if only one outrigger can not be extended to the length of the others, the resistance to overturning is decreased to that of the shortest extended outrigger. In this situation, more weight could be added to the invention to compensate for the restriction on outrigger extension.
On the other hand, the more the outriggers can be extended, the less total weight is needed. Therefore, there are times when less weight needs to be transported and manipulated to achieve the desired resistance to overturning.
Different charts can be created for different configurations (e.g. for different pole type/heights, difference fixture types/numbers, different EPAS, etc.).
Markings could be placed on the outrigger arms 56, and 58 (see
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| Number | Date | Country | |
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| Number | Date | Country | |
|---|---|---|---|
| Parent | 10157062 | May 2002 | US |
| Child | 10845007 | US | |
| Parent | 09217975 | Dec 1998 | US |
| Child | 10157062 | US |
