Abstract:
A modular, prefabricated stair tower comprising a plurality of stairs, landings, handrails and hangers pre-assembled into a module configured such that it might be shipped and installed into a wind power tower tube section, with installation preferably occurring prior to shipment to the wind farm jobsite so that, when the tube section is erected vertically, authorized personnel gain immediate, efficient and economical access for ascending and descending large land based and offshore wind power turbine towers.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a divisional application of U.S. patent application Ser. No. 13/068,289 filed May 7, 2011, currently pending which claims the benefit of U.S. Provisional Application Ser. No. 61/395,211 filed on May 10, 2010. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to an improved stair tower module and more particularly a stair tower module and system developed for the wind power industry to make wind towers more accessible and improve the efficiency of ingress and egress for authorized personnel. 
         [0003]    Existing ingress and egress options available for large wind power tube towers include the open ladder system with fall arrest and the electric lift system. Both of these systems have significant drawbacks because of their significant requirements including, but not limited to, extensive personnel training and certification, special safety equipment such as fall arrest devices, special physical capabilities for personnel, scheduled maintenance requirements and access to electricity. The existing systems limit travel to one person at a time traveling in only one direction at a time making ingress and egress time consuming and inefficient. Those system limitations make emergency response difficult and does not provide for practical emergency exit in case of fire in the top of the wind tower structure. 
         [0004]    It is impractical to assemble a conventional stair system inside a horizontal tube; it is also inefficient and expensive to erect stairs inside a vertical tube. The present invention and system allows the stairs to be pre-fabricated into shippable modules at the fabrication plant. The modules are then shipped to the tube manufacture or the jobsite location where they are installed into the tube tower sections while the tube sections are in their horizontal position. Once installed, the tube section can be placed in its vertical position, at the jobsite, giving the workers immediate efficient stair access to accomplish their work in a fraction of the time currently required of the existing system options. 
         [0005]    The stair tower module system addresses all the problems associated with the currently available ingress and egress options. No special training or certification is required to access the stair system. As long as authorized personnel stay on the walking surface they are within the guardrails and no special fall arrest devises are required. Further, no special physical capabilities are required of personnel opening up the demographic of people able to access the nacelle (the enclosed top of the wind tower where the majority of the work is performed). Stairs furnished as either hot dipped galvanized steel or a mill finished aluminum, require very little scheduled maintenance throughout the life of the wind tower structure. Unlike an electric lift, the present system does not require electricity making the system available to construction workers as soon as the tube sections are stood up vertically facilitating the installation of the next tower section, nacelle, tower blades and accompanying equipment. 
         [0006]    Probably the greatest advantage to the existing stair tower module system is that numerous authorized personnel can utilize the system at the same time, moving in both directions at the same time. Accessible and efficient ingress and egress is absolutely crucial to economically and safely support erection, set-up, maintenance and most importantly emergency response. Stair towers provide the only reasonable way to evacuate workers from the top of tall structures such as wind towers in the case of fire or other emergency exit situations. Cost benefit analysis suggests that the present system could pay for itself much faster than other existing wind tower access systems by reducing the cost of tower installation and future farm operations. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    This invention relates to a unique stair tower module, its fabrication, assembly and integration into wind power tube tower sections for primary tower ingress and egress. 
         [0008]    It is an object of the present invention to provide stair ingress and egress to allow authorized personnel to efficiently ascend and descend wind tower structures and the like. 
         [0009]    Another object of the present invention is to pre-assemble stairs, landings, handrails and hangers into a stair tower module at a shop facility designed to fit inside wind power tower tubes and allow at least two modules to be shipped per truckload. 
         [0010]    A still further object of the present invention is to provide a stair tower module where a limited number of structural members serve as the module framing, the intermediate landing handrail corner post and the support hangers for the stair tower module system. 
         [0011]    A still further object of the present invention is to provide a stair tower module that is installed into a wind tower tube section by affixing a rubber wheeled dolly to the front leading edge of the module and rolling it inside a tube section with a forklift or crane. 
         [0012]    A still further object of the present invention is to provide a stair tower module with intermediate landings that might allow construction workers and other authorized personnel to pass while traveling in both directions inside the wind tower. 
         [0013]    A still further object of the present invention is to provide a stair tower module where a minimal number of support members are required to fasten the module to the inside of the tower tube wall. 
         [0014]    A still further object of the present invention is to provide a stair tower module that will allow immediate ingress and egress for construction workers as soon as the tower tube section is erected vertically at the wind farm jobsite. 
         [0015]    A still further object of the present invention is to provide a stair tower module that improves labor cost to erect and maintain a wind tower by significantly reducing the time required for personnel to travel through the wind tower. 
         [0016]    A still further object of the present invention is to provide a stair tower module that expands the demographic of individuals who might be capable of accessing the wind tower including improving access for emergency responders. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is an isometric view of a preferred embodiment of a stair tower module in accordance with the present invention. 
           [0018]      FIG. 2  is a plan view of a stair tower module mounted inside a wind tower tube section. 
           [0019]      FIG. 3  is a hidden side elevation view of a typical stair tower module of the present invention mounted inside a wind tower tube section. 
           [0020]      FIG. 4  is a hidden end elevation view of a typical stair tower module mounted inside a wind tower tube section. 
           [0021]      FIG. 5  is side sectional elevation view of the stair tower module slice detail connecting adjacent modules together vertically. 
           [0022]      FIG. 6  is a top sectional view of the end of a channel support header connection to the inside a wind tower tube. 
           [0023]      FIG. 7  is a partial elevation view of the stair tower module hanger serving as module perimeter, handrail post and stair framing hanger support. 
           [0024]      FIG. 8  is a side elevation view illustrating two stair tower modules loaded on a truck. 
           [0025]      FIG. 9  is a side partially hidden elevation view illustrating the stair tower module being slipped inside a wind tower tube section. 
           [0026]      FIG. 10  is a side hidden elevation view illustrating a wind power tower tube section being shipped to the wind farm jobsite with the stair tower module mounted inside. 
           [0027]      FIG. 11  is a side hidden elevation view illustrating a wind power tower tube being set at the project site with the stair tower module mounted inside available for immediate use. 
           [0028]      FIG. 12  is a hidden elevation view of a wind power tower with a nacelle and rotating blades mounted on top consisting of numerous tube sections each with a stair tower module mounted inside. 
           [0029]      FIG. 13  illustrates a perspective view of a second embodiment of the present invention. 
           [0030]      FIG. 14  is a top view of the embodiment shown in  FIG. 13 . 
           [0031]      FIG. 15  is a right side view of the embodiment shown in  FIG. 13 , the left side view being a mirror image thereof. 
           [0032]      FIG. 16  is an end view of the embodiment shown in  FIG. 13 . 
           [0033]      FIG. 17  illustrates a perspective view of a third embodiment of the present invention. 
           [0034]      FIG. 18  is a top view of the embodiment shown in  FIG. 17 . 
           [0035]      FIG. 19  is a right side view of the embodiment shown in  FIG. 17 , the left side view being a mirror image thereof. 
           [0036]      FIG. 20  is an end view of the embodiment shown in  FIG. 17 . 
           [0037]      FIG. 21  illustrates a perspective view of a fourth embodiment of the present invention. 
           [0038]      FIG. 22  is a top view of the embodiment shown in  FIG. 21 . 
           [0039]      FIG. 23  is a right side view of the embodiment shown in  FIG. 21 , the left side view being a mirror image thereof. 
           [0040]      FIG. 24  is an end view of the embodiment shown in  FIG. 21 . 
           [0041]      FIG. 25  is a perspective view of a portion of the stair tower shown in  FIG. 21  to show more detail of the boxed spiral stair configuration. 
           [0042]      FIG. 26  illustrates a perspective view of a fifth embodiment of the present invention. 
           [0043]      FIG. 27  is a top view of the embodiment shown in  FIG. 26 . 
           [0044]      FIG. 28  is a right side view of the embodiment shown in  FIG. 26 , the left side view being a mirror image thereof. 
           [0045]      FIG. 29  is an end view of the embodiment shown in  FIG. 26 . 
           [0046]      FIG. 30  is a perspective view of a portion of the stair tower shown in  FIG. 26  to show more detail of the spiral stair configuration. 
           [0047]      FIG. 31  illustrates a perspective view of a fifth embodiment of the present invention. 
           [0048]      FIG. 32  is a top view of the embodiment shown in  FIG. 31 . 
           [0049]      FIG. 33  is a right side view of the embodiment shown in  FIG. 31 , the left side view being a mirror image thereof. 
           [0050]      FIG. 34  is an end view of the embodiment shown in  FIG. 31 . 
       
    
    
     BRIEF DESCRIPTION OF THE PARTS 
     First Embodiment 
       [0051]      13 —stair,  14 —stair stringer,  15 —stair tread,  16 —handrail,  17 —intermediate landing,  18 —corner hanger,  19 —intermediate landing support plate,  20 —module support member,  21 —wind power tower tube section,  22 —work platform,  23 —support framing,  24 —checkered floor plate,  25 —module attachment channel,  26 —fastening plate,  27 —splice plate,  28 —rubber wheeled dolly,  29 —mobile crane,  30 —track crane,  31 —wind tower,  32 —nacelle,  33 —blades. 
       Second Embodiment 
       [0052]      113 —stair,  114 —stair stringer,  115 —stair tread,  116 —handrail,  117 —intermediate landing,  118 —corner hanger,  119 —intermediate landing support plate,  120 —module support member,  121 —wind power tower tube section,  122 —work platform,  123 —support framing,  124 —checkered floor plate,  125 —module attachment channel. 
       Third Embodiment 
       [0053]      213 —stair,  214 —stair stringer,  215 —stair tread,  216 —handrail,  217 —intermediate landing,  218 —corner hanger,  219 —intermediate landing support plate,  220 —module support member,  221 —wind power tower tube section,  222 —work platform,  223 —support framing,  224 —checkered floor plate,  225 —module attachment channel. 
       Fourth Embodiment 
       [0054]      313 —stair,  314 —stair stringer,  315 —stair tread,  316 —handrail,  317 —intermediate landing,  318 —corner hanger,  320 —module support member,  321 —wind power tower tube section,  322 —work platform,  323 —support framing,  324 —checkered floor plate,  325 —module attachment channel,  334 —Center Support Member. 
       Fifth Embodiment 
       [0055]      413 —stair,  414 —stair stringer,  415 —stair tread,  416 —handrail,  417 —intermediate landing,  418 —corner hanger,  420 —module support member,  421 —wind power tower tube section,  422 —work platform,  423 —support framing,  424 —checkered floor plate,  425 —module attachment channel,  434 —Center Support Member,  435 —Baluster. 
         [0056]    Sixth Embodiment 
         [0057]      513 —ladder,  514  —cage,  516 —handrail,  517 —intermediate landing,  518 —corner hanger,  521 —wind power tower tube section. 
       DETAILED DESCRIPTION 
       [0058]    The present invention relates to a stair tower module, it&#39;s design, fabrication, assembly, integration and installation into wind power tower tube sections prior to erection at the wind farm jobsite so that when the tube sections are erected and connected vertically workers are offered immediate efficient ingress and egress for ascending and descending the wind tower to support construction, set-up, maintenance and emergency response. 
         [0059]      FIG. 1  shows one embodiment of the present invention, a ship&#39;s ladder style stair tower module. A stair tower module  FIG. 1  may comprise one or more stairs  13 . A stair  13  may comprise one or more stringers  14 ; one or more stair treads  15  and one or more handrails  16 . An intermediate landing  17  is preferably positioned between each stair  13 . 
         [0060]    A stair tower module  FIG. 1  corner hanger  18  serves several functions; it provides the framing to encapsulate the stairs  13 , handrails  16  and intermediate landings  17  into a shippable assembly, it serves as an intermediate landing handrail post and it also supports the stair system in it&#39;s final vertical position inside the tower. The corner hanger  18  may be an angle or other structural support member that is capable of carrying the required design loads 
         [0061]    The stair stringers  14  are continuous members from one corner hanger  18  to the opposing corner hanger  18  providing support for the stair treads  15 , intermediate landings  17  and handrails  16 . Outside stair stringers  14  preferably are processed from plate in a continuous double dogleg configuration including a lower landing, stringer and upper landing also serving as side kick plates at the intermediate landings  17 . Inside stair stringers  14  are processed from plate similar to the outside except the lower and upper landing supports are omitted. Stair stringer  14  processing would be performed utilizing computer automated multi-head CNC cutting equipment. Holes necessary for the attachment of stair treads  15 ; handrails  16  and intermediate landing  17  are cut in during processing utilizing CNC data imported from the shop fabrication drawings. 
         [0062]    The stairs&#39;  13  angle of slope or bevel can vary dramatically. Typical ranges are from 52 degrees to 68 degrees on a ship&#39;s ladder style stair allowing for a step height or rise of 12 inches making for the fewest allowable number of steps from the top to the bottom of the wind tower. 
         [0063]    The stair treads  15  are preferably provided as bent checkered plate, grip strut, bar grating with abrasive nosing or bent plate abrasive surface all fastened, preferably by bolting, to the stair stringer  14  with two bolts at each end with a minimum tread length (stair width) of 24 inches and a tread depth of 6 to 10 inches depending on the project requirements. 
         [0064]    The handrails  16  can be fabricated from any suitable material such as standard pipe, square or rectangular tubing, or hot rolled angle depending on the customer&#39;s preference. The perimeter handrails  16  are typically fabricated in one piece spanning from corner hanger  18  to the opposing corner hanger  18 , bolted to the stair stringer  15  and the intermediate landing support plate  19  allowing for a rigid handrail that braces the stair and provides lateral support to the stair module  FIG. 1 . 
         [0065]    The intermediate landing support plate  19  spans between and is bolted to opposing corner hangers  18  serving to support the checkered floor plate  24  and also serving as the rear kick plate for the intermediate landing  17 . 
         [0066]    A module support member  20  may be utilized where necessary to stiffen the stair tower module  FIG. 1  for shipping and to align module corner hangers  18  for field splicing. 
         [0067]    Typically one module  FIG. 1  is installed inside each tower tube section  21 . Tower tube sections  21  can be of any length but typically range from approx. 20-feet to 80-feet or more with 60 feet being the most common length. When the tower tube sections  21  exceed 60-feet long two stair tower modules  FIG. 1  may be utilized to make up the entire length of the tube section  21 . For example, an 80-foot long tower tube section  21  might have two 40-foot long stair tower modules  FIG. 1  mounted inside. 
         [0068]    The stair tower module  FIG. 1  components can be manufactured utilizing several different materials. The preferred materials of construction include hot dipped galvanized steel, mill-finished aluminum or mill-finished stainless steel depending on project conditions. These materials offer low maintenance and should be considered when specifying for off shore or land based wind farms. However, there are many other suitable materials that are well known in the art that may suffice for materials of construction. 
         [0069]      FIG. 2  shows a plan view of a permanent work platform  22  located just below the tower tube section&#39;s  21  top splice joint allowing workers a level landing from which they can attach the next tube section  21  vertically. The work platforms  22  are also utilized for joint inspection, rest platforms, equipment and work stations. 
         [0070]      FIG. 3  shows the approximate location of the work platform  22  with its channel support framing  23  that is shipped loose with the stair tower module  FIG. 1  to be installed into the wind power tower tube section  21  along with the checkered floor plate  24  that make up the work platform  22 . The checkered floor plate  24  at the work platform  22  is commonly provided in aluminum to reduce weight and make installation inside the tower tube section easier. 
         [0071]      FIG. 4  shows the approximate location of the module attachment channels  25 . The module attachment channels  25  are shipped loose for attaching the stair tower module  FIG. 1  to the inside of the tower tube section  21  by fastening, preferably by bolting, to the corner hangers  18  then fastening to the tower wall through a fastening plates  26  at each end. Any changes in tube diameter as the system travels higher in the tower would be addressed by shortening the module attachment channels  25  to accommodate the transition. The stair tower module system requires significantly fewer attachment locations than the open ladder with a fall arrest or electric lift systems. 
         [0072]      FIG. 5  shows how the angle corner hangers  18  of stacked stair tower modules  FIG. 1  are preferably bolted together utilizing a splice plate  27  on both outstanding legs with structural grade bolts. 
         [0073]      FIG. 6  illustrates a preferred method of connecting a module attachment channel  25  to the inside of the tower tube section  21  utilizing a fastening plate  26  welded to the inside face of the tower wall. 
         [0074]      FIG. 7  illustrates a corner hanger  18  serving as the perimeter module framing, intermediate landing handrail post and stair framing support. 
         [0075]      FIG. 8  is a side elevation view illustrating multiple modules of the present invention loaded on a truck for delivery to the wind tower tube location. 
         [0076]      FIG. 9  is a partially hidden elevation showing that the present invention can be inserted inside a wind tower tube section  21  utilizing a rubber wheeled dolly  28  mounted to the front leading edge of the stair tower module  FIG. 1  supported by an appropriately suited mobile crane  29 . Once the module  FIG. 1  is in the correct location the module attachment channels  25  are fastened to the corner hangers  18  locating the fastening plates  26  at each end so that they can be attached to the face of the tube wall preferably as shown in  FIG. 6 . 
         [0077]      FIG. 10  illustrates a wind tower tube section  21  ready for shipment to the wind farm site with the stair tower module  FIG. 1  of the present invention mounted inside. Because the stair tower module  FIG. 1  is contained within the tower tube section  21  additional freight cost for the stair tower module  FIG. 1  is minimized. Wind tower tube sections  21  are typically shipped via tractor-trailer truck, railcar or ocean going barges. 
         [0078]      FIG. 11  illustrates a wind tower tube section being set at the jobsite by an appropriately suited track crane  30  with the stair tower module  FIG. 1  mounted inside ready for immediate access to construction crews and other authorized personnel. Additional tube sections can be made available to the erection crew to facilitate the attachment of the next tower tube section  21  as well as other equipment that is attached to the top tube section. 
         [0079]      FIG. 12  shows a hidden elevation view of a wind tower  31  with a nacelle  32  and its rotating blades  33  mounted on top. In this illustration a complete preferred embodiment of the present invention Comprising a plurality of stair tower modules  FIG. 1  connected end to end and stacked vertically through the entire length of the wind tower  31  providing contiguous stair ingress and egress for construction crews and technical personnel to enhance the efficiency of tower erection, equipment installation, monitoring, system modification, repair and maintenance through the entire service life of the tower. 
         [0080]    While a ship&#39;s ladder style stair is depicted in  FIG. 12  as traveling all the way to the top platform level of the tower, a number of different configurations of stairs or ladders can be utilized to accomplish the same objectives of the present invention. 
         [0081]    In  FIGS. 13-15 , alternating treads  115  are illustrated. As the name implies the treads alternate to accommodate the actual motion of climbing steps. In this alternate embodiment, the treads  115  are supported by outside, central and inside stringers  114 . The handrails  116 , intermediate landings  117 , corner hangers  118 , intermediate landing support plate  119 , module support member  120 , work platform  122 , support framing  123 , checkered floor plate  124  and module attachment channel  125  are identical in description to the like-named elements in the first described embodiment. 
         [0082]    In  FIGS. 17-20 , a box stair style is shown. Basically, this style of stair takes right angle turns at the landings instead of 180 degree turns. In this alternate embodiment, the treads  215  are supported by and outside and inside stringers  214 . The handrails  216 , intermediate landings  217 , corner hangers  218 , intermediate landing support plate  219 , module support member  220 , work platform  222 , support framing  223 , checkered floor plate  224  and module attachment channel  225  are identical in description to the like-named elements in the first described embodiment. As shown in  FIG. 18 , the advantage of a box stair is that the central portion of the wind tower remains open to accommodate a lift or other similar device. 
         [0083]    In  FIGS. 21-25 , a box spiral stair style is shown. Like the name this style of stair spirals upwards supported by a corner members  318  and central support member  334 . The central support member  334  serves as the inner “stringer” for all the treads  315 . The outer stringer  314  spans between and is attached to the corner members  318  to support the treads  315 . Rather than the outer edge of each tread  315  being rounded, it is typically fabricated with a straight edge to attach to the stringer  314 . Intermediate landings  317  can be positioned at various elevations along the stair case. The handrails  316  are fastened to the corner support members  318 . Module support member  320 , work platform  322 , support framing  223 , checkered floor plate  224  and module attachment channel  225  are identical in description to the like-named elements in the first described embodiment. 
         [0084]    In  FIGS. 26-30  a typical spiral stair style is shown. Like the name this style of stair spirals upwards supported by a corner members  418  and central support member  434 . The central support member  434  serves as the inner “stringer” for all the treads  415 . The handrails  416  are fastened to the corner support members  418  usually that the location of intermediate landings  417 . Rather than an outer stringer to support the treads  415 , balusters  435  extend from the handrails  416  and are attached to the treads  415 . Module support member  420 , work platform  422 , support framing  423 , checkered floor plate  424  and module attachment channel  425  are identical in description to the like-named elements in the first described embodiment. 
         [0085]    As illustrated in  FIGS. 31-34 , the stair tower of the present invention allows a ladder type climbing system to be installed. Ladders  513  extend to intermediate platforms  517 . Cages  514  surround a portion of the ladder  513  to accommodate safety codes. 
         [0086]    Although specific configurations of the stair tower module have been depicted herein, the geometric orientation, materials of construction, methods of fastening, stair type, slope, number of stairs, treads, landings or hangers may vary to meet project requirements. 
         [0087]    As the present invention may be embodied in several different forms without departing from the essential characteristics or benefits thereof and the illustrations and descriptions are therefore illustrative and not restrictive.