Abstract:
A guard for structural members is disclosed. It can reduce worker injury with a thin sheet metal or plastic, broadly U-shaped guard plate attached to a structural support through attachment to a pair of clamps, each with a primary and a secondary threaded clamp jaw. The attachment between the guard plate and pair of clamps may be via a slotted intermediate structure. The primary jaws have a swivel pad end while the secondary clamps have a pointed, cone-shaped end. It is used in wind turbine towers to protect workers on a fixed ladder from hitting interior flanges as they climb up and as they climb down.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of priority from U.S. provisional application 61/361,513 filed Jul. 5, 2010, which is hereby incorporated herein by reference in its entirety. 
     
    
     FIELD 
       [0002]    This disclosure describes a device attachable to a fixed structure for the purpose of protecting personnel working in tight spaces from head and other types of injury. 
       BACKGROUND 
       [0003]    Utility spaces in fixed structures may have a variety of hazards not present in areas designed for general occupancy. However, even in hard-hat areas covered with warning signs it is still prudent to provide for worker protection from hazards such as low beams. Modification of structural members however is generally to be avoided. It can also be important to allow ready visual inspection of such members. 
       SUMMARY 
       [0004]    An angled, flat guard attached to the member via adjustable clamps can solve the problem of bodily protection in areas requiring blind movement relative to structural members. This can be applied to an inside flange in a cylindrical tower with a fixed ladder, as one example application. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  shows a cut-away side view of a worker climbing a ladder in a tower and approaching a protected flange; 
           [0006]      FIG. 2  shows a perspective view of a worker climbing a ladder in a tower; 
           [0007]      FIG. 3  shows an expanded perspective view of the guard of  FIG. 1 ; 
           [0008]      FIG. 4  is a perspective view of the unit of  FIG. 3  from the back; 
           [0009]      FIG. 5  shows one clamp of the unit of  FIG. 3 , in isolation, in a side view in a position clamped to the meeting of two flanges; 
           [0010]      FIG. 6  shows a second embodiment in a hallway. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    The first embodiment presented is an apparatus for use in a wind turbine tower.  FIG. 1  shows a schematic side view of a portion of a tower. The tower  10  is constructed of multiple generally cylindrical hollow tubes connected by inside flanges. In  FIG. 1  the tower walls  11  and flanges  12  of two adjoining sections are shown in cross section. The flanges are shown connected by bolts  14 . A fixed ladder  13  is used by a worker  20  to get to the top of the tower. It is often close to the inner wall of the tower. If the distance from the flange to the ladder is less than about three feet it can present a hazard to workers climbing the ladder. When climbing upward they are facing away from a protrusion that can be almost directly over their head. Whether climbing up or down, the use of “climb assists” can increase the danger to the workers due to the increased speed at which the worker is moving. 
         [0012]    In this embodiment a guard apparatus  100  is used to address this safety issue. The worker&#39;s head is deflected away from the hazard above by a sheet metal guard  101  at a 60-degree angle from the horizontal axis to the wall. Although possibly not as dangerous, a similar hazard is present as the worker descends. Therefore, the embodiment shown has a symmetric design with a second sheet metal portion above the mating of the two flanges. Since the flanges are structural support members they and their mutual connection should preferably not be modified or interfered with in coupling a guard to the structure. In  FIG. 1  a clamp assembly  103  holds mounting bars  102  to the mated flanges. The guard itself  101  is bolted to the mounting bars. 
         [0013]    Also note that the upper portion of the guard plate is similarly bent back away from the ladder. The guard plate in this embodiment can be made of sheet metal or of plastic. This provides an analogous protection for a descending worker. 
         [0014]    Without this guard a worker might injure their back or their coccyx. Additionally, without this guard a worker&#39;s personal fall protection equipment can also become hung up or snagged on the exposed flange bolts and or nuts possibly damaging their personal fall protection equipment and or injuring the worker. 
         [0015]      FIG. 2  shows the scenario of  FIG. 1  from a different perspective. 
         [0016]      FIG. 3  shows an expanded, exploded, perspective view of this first embodiment of a head guard apparatus  100 . There are two clamp assemblies  103 , a left and a right unit. The clamp assemblies each connect to both an upper and a lower mounting bar  102 . The mounting bars shown in this figure each have a left and a right slot  200  running in the direction of the major axis of the bars. The slots, together, take up substantially all of the length of each bar other than a small region in the center of the bar. Each clamp assembly has a U shaped bar  111  supporting two pairs of threaded screws  104   105  for attaching the whole apparatus to a pair of mated flanges.  FIG. 4  shows the example embodiment from the back with the guard plate secured to the mounting bars. The guard plate itself  101  is secured to the upper and lower mounting bars via bolts  15  through six holes  106  in its central portion. As seen in  FIGS. 3 and 4 , bolts between the clamps and mounting bar engage the mounting bars&#39; slots. This inherently provides a maximal degree of horizontal positioning of the guard relative to the clamps&#39; locations. Additionally, it therefore provides horizontal positionability between the shield and the particular locations on the flange at which the clamps may be attached at any particular time. 
         [0017]    The clamping is shown in detail in  FIG. 5 , and expanded view of one of the clamps attached to a pair of flanges. One set of threaded screws  104  are the primary clamping mechanism to attach the guard to the flanges. They are opposing screws with swivel pad feet and locking nuts. The second set of screws  105  are for a secondary clamping for enhanced stability and a “back-up” clamping. A second version for horizontal movement is shown in  FIG. 6  and described below in Operations. 
         [0018]    Operation 
         [0019]    The guard system is installed by first adjusting the clamp screws  104   105  to center the mounting bars relative to the flange. The left and right primary screws  104  are then tightened to a specified torque rating. This is to be adequately secure without harming the flanges in any way—not even cracking any paint. The locking nuts are then tightened to their specified torque. The secondary, pointed screws  105  are then tightened to their specifications. 
         [0020]    After inspection of the clamps, as seen in the various drawings, the mounting bars can be secured to the clamps via the mounting bar slots. As is inherent in a slotted structure, a relative horizontal relationship between clamps and the bars can be determined as suitable for the specific installation and established by tightening of the bolts. Then the guard plate is secured to the upper and lower mounting bars  102  with screws through the six holes  106 . The lower edge  108  and the upper edge  107  of the guard plate are proximate to the inner wall. When installed, the guard provides a surface with an acute angle relative to the motion of the worker&#39;s head as he climbs the ladder. The worker&#39;s head is therefore deflected away from the obstruction and toward the ladder by the slope of the guard. Analogously, the workers backside is urged toward the ladder when descending past this point. 
         [0021]    For inspection of, or other access to, the flange bolts, the screws holding the guard plate to the mounting bars are removed and full access to the flange is obtained. 
         [0022]    A second example is seen in  FIG. 6 . A worker  20  is shown walking towards a low beam cutting across his path. An elongated version of a guard plate is seen secured to the beam by a clamping assembly  103 . If the worker doesn&#39;t notice the beam, his hardhat will be pushed downward by the guard plate  101 . 
         [0023]    Those skilled in the art will be aware of materials, techniques and equipment suitable to produce the example embodiments presented as well as variations on those examples. This teaching is presented for purposes of illustration and description but is not intended to be exhaustive or limiting to the forms disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments and versions help to explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand it. Various embodiments with various modifications as are suited to the particular application contemplated are expected. 
         [0024]    In the following claims, the words “a” and “an” should be taken to mean “at least one” in all cases, even if the wording “at least one” appears in one or more claims explicitly. The scope of the invention is set out in the claims below.