Abstract:
The present invention comprises an apparatus and method for construction of scaffold structures having improved safety characteristics. In various embodiments, the apparatuses of the present invention comprise a set of structures, including connecting rails, fencing, gates, and ladders. The structures are adapted to be used with locking-cup type scaffold designs.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    In various applications, scaffolding is erected in order to give workers access to elevations above ground. For example, in the course of repairs to the outside surface of a building, modifications of the same, window washing, painting, cleaning, or installation of siding on the exterior of a building, scaffolding is commonly used to enable workers to move up and down adjacent the side of the building. Such devices are well known and take a wide variety of forms. One of the more conventional forms of scaffolding ordinarily includes one or more vertical posts that are interconnected by cross-braces and which may be stacked on top of each other to permit workmen to work at high elevations.  
           [0002]    The scaffold platform typically includes a pair of metal side rails held in parallel spaced relation by a series of spaced transverse hollow rungs upon which metal or wooden planks are placed and secured to provide the floor of a work platform. These rungs may be round, or may have a square cross-section to provide flat upper surfaces upon which the wooden planks may rest and be supported. In order to provide workers access to multiple levels of the scaffolding, most scaffold installations incorporate ladders either integrally as part of the scaffold structure, or mounted to the scaffold structure by some form of attachment means.  
           [0003]    Traditional scaffolding has been designed to provide workers with ready access to the surface of a flat wall, or to a right-angle corner of a building. Such scaffolding is useful for more traditional rectangular buildings, but such scaffolding has less utility in conjunction with structures having unconventional shapes. For example, round storage tanks present a unique and potentially dangerous problem for conventional scaffolding systems. Linear sections of conventional scaffolding must be brought together using independent clamps to conform to the surface of the tank. Conventional scaffolding is not designed for curved structures, hence, the clamped joints may become loose and create hazardous conditions for workmen.  
           [0004]    Other hazards associated with scaffolds are well known. These hazards include loss of balance, slippage, and displacement of the scaffold due to movement of workers on the scaffold, wind, or other environmental factors. In order to protect the workers against falls, safety structures including guardrails and guard walls are often erected from the scaffold platform on one or both sides of the work platform. It is important that such safety structures be easy to assemble and attach to the platform and yet be firmly held in place with a minimum risk of failure.  
           [0005]    One of the more popular scaffold construction designs includes a set of vertical columns having dual hemispherical couplers at regular intervals along their lengths. The vertical columns are tied together with horizontal members spanning between the vertical columns. Each end of each horizontal member is designed to mate with one quadrant of a dual hemispherical coupler. With this design, a single coupler can receive up to four horizontal members.  
           [0006]    Although this scaffold design has proven to be useful, it has been found to be useful mostly for building scaffolds disposed against a single wall or against a right-angled structure. There has not been a satisfactory solution to the problem of scaffolding with this type of design against structures having diagonal or curved surfaces. Furthermore, although safety restraints and ladders have been developed that can be used in conjunction with this type of scaffolding, existing designs have been found to be heavy, difficult to assemble, or insufficiently compliant with government safety regulations.  
         SUMMARY OF THE INVENTION  
         [0007]    The following summary of the invention is provided to facilitate an understanding of some of the innovative features unique to the present invention, and is not intended to be a full description. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings, and abstract as a whole.  
           [0008]    The present invention relates generally to the field of construction scaffolding, and in particular to a system of scaffolding incorporating a set of features designed to improve both the functionality of the scaffolding and the safety characteristics thereof. In its various embodiments, the present invention includes a number of novel structures and assemblies to facilitate safe and efficient assembly of scaffolding as well as improve the safety of workers using such scaffolding. In certain embodiments, the present invention facilitates the safe and efficient construction of scaffolding at the corner of structures where two walls meet at an angle greater or less than 90 degrees.  
           [0009]    In one embodiment, the present invention includes a structural brace having a center section with a lengthwise axis, a first end, and a second end. A first mounting flange is attached rigidly to the first end, which includes a mounting surface having a center, an upper tab, and a lower tab. A second mounting flange is attached rigidly to the second end, and includes a mounting surface having a center, an upper tab, and a lower tab. The vector normal to the mounting surface at the center is disposed at an angle of between about 5 degrees and about 89 degrees to the lengthwise axis of the center section.  
           [0010]    In another embodiment, the present invention also includes a guard rail panel including an upper brace section having a first end and a second end; a lower brace section having a first end and a second end, connected to the upper brace section by a bridging member. A first upper mounting flange, attached to the first end of the upper brace section, includes an upper tab and a lower tab. A second upper mounting flange, attached to the second end of the upper brace section, includes an upper tab and a lower tab. Finally, a first lower mounting flange, attached to the first end of the lower brace section, includes an upper tab and a lower tab and a second lower mounting flange is attached to the second end of the lower brace section, having an upper tab and a lower tab.  
           [0011]    In yet another embodiment, the present invention is directed to a ladder assembly comprising a first vertical member, a second vertical member, one or more horizontal rungs connecting the first vertical member to the second vertical member, and one or more ladder mounting brackets. Each ladder mounting bracket has a first and second end, and is connected to a vertical member at the first end by a mounting clamp. The second end of each ladder mounting bracket has a mounting flange having an upper tab and a lower tab.  
           [0012]    The novel features of the present invention will become apparent to those of skill in the art upon examination of the following detailed description of the invention or can be learned by practice of the present invention. It should be understood, however, that the detailed description of the invention and the specific examples presented, while indicating certain embodiments of the present invention, are provided for illustration purposes only because various changes and modifications within the spirit and scope of the invention will become apparent to those of skill in the art from the detailed description of the invention and claims that follow.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form part of the specification, further illustrate the present invention and, together with the detailed description of the invention, serve to explain the principles of the present invention.  
         [0014]    [0014]FIG. 1 is a plan view of a scaffolding system incorporating certain embodiments of the present invention;  
         [0015]    [0015]FIG. 2 is a perspective view of a scaffolding system incorporating certain embodiments of the present invention;  
         [0016]    [0016]FIG. 3 is a plan view of a joint in a scaffolding system incorporating certain embodiments of the present invention;  
         [0017]    [0017]FIG. 4 is a plan view of a segment of a scaffolding system incorporating certain embodiments of the present invention;  
         [0018]    [0018]FIG. 5 is a perspective view of a coupler in a scaffolding system incorporating certain embodiments of the present invention;  
         [0019]    [0019]FIG. 6 is a perspective view of a coupler in a scaffolding system incorporating certain embodiments of the present invention;  
         [0020]    [0020]FIG. 7 is a perspective view of a coupler in a scaffolding system incorporating certain embodiments of the present invention;  
         [0021]    [0021]FIG. 8 is a perspective view of a scaffolding system incorporating certain embodiments of the present invention;  
         [0022]    [0022]FIG. 9 is a perspective view of a scaffolding system incorporating certain embodiments of the present invention;  
         [0023]    [0023]FIG. 10 is a plan view of a clamp arm of a scaffolding system incorporating certain embodiments of the present invention;  
         [0024]    [0024]FIG. 11 is a plan view of a clamp arm of a scaffolding system incorporating certain embodiments of the present invention;  
         [0025]    [0025]FIG. 12 is a perspective view of a scaffolding system incorporating certain embodiments of the present invention;  
         [0026]    [0026]FIG. 13 is side view of one embodiment of a guard rail panel of the present invention;  
         [0027]    [0027]FIG. 14 is side view of a second embodiment of a guard rail panel of the present invention;  
         [0028]    [0028]FIG. 15 is a side view of a third embodiment of a guard rail panel of the present invention;  
         [0029]    [0029]FIG. 16 is a side view of a safety gate of the present invention;  
         [0030]    [0030]FIG. 17 is a side view of a supplemental vertical strut according to one embodiment of the present invention; and  
         [0031]    [0031]FIG. 18 is a detail view of an angled rail according to one embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0032]    While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention.  
         [0033]    Referring to FIGS. 1 and 2, one configuration of a scaffolding system  10  is depicted. Posts  12  provide vertical support and may be supplied with a base  14 . The base  14  may be a stable platform that is an interface between the post  12  and the ground. The base  14  may have, for example, a screw-type leveling mechanism that allows the scaffolding system  10  to be erected on uneven terrain. Alternatively, the leveling mechanism may also be, for example, hydraulic or have a telescoping section that may be secured by a pin, for example.  
         [0034]    [0034]FIG. 3 depicts an exploded view of a scaffold joint that may be assembled using the coupling  18 . Rails  16  may be connected between the posts  12  with couplings  18 . Rails  16 , as with the other portions of the scaffold, may be made of any one of a variety of materials used in structural applications, including steel, aluminum, and composite materials. The rails  16  may have a cross-sectional shape such as those commonly used in structural applications, including square and round tubes, I-beams, and wide-flange sections. The couplings  18  may be, generally, conical sections that are connected to the posts  12  and serve to secure tabs  20 . The tabs  20  may be rigidly attached to the rails  16 . The tabs  20  may be attached to the ends of the rails  16  by, for example, welding, bolting, or forging the tabs  20  as an integral part of the rails  16 . Other methods of joining the tabs  20  to the rails  16  will be apparent to one of ordinary skill in the art.  
         [0035]    In one embodiment of the present invention, the tabs  20  may be a part of a flange that is attached to the rail  16 . The tabs  20  are portions of the flange that extend radially beyond the circumference of the rail  16 . Alternatively, the tabs  20  may be, for example, individual pieces of metal or other materials, such as composites, that are formed from, or attached to, the end of the rail  16 . The tabs  20  may be formed from the end section of a metal rail  16 , welded, screwed, or assembled in manners known to those of skill in the metalworking art. The tabs  20  may also be designed to conform to the radius of the post  12 , which results in a more stable interface between the post  12  and the tabs  20 .  
         [0036]    The tabs  20  may be fixed to the rails  16  at a variety of different angles so that the scaffolding system  10  may be built to accommodate structures having irregular shapes. For example, as depicted in FIGS. 1 and 2, one section of the scaffolding system  10  may be oriented at an angle greater or less than ninety degrees to the adjoining section. Varying the angles that the tabs  20  are formed or fixed to the rails  16  and varying the lengths of the rails  16  allows the scaffolding system  10  to be assembled to conform to different buildings that have a variety of shapes. As another example, various lengths of rails  16  have angled tabs  20  that allow the scaffolding system  10  to be assembled to conform to round structures, such as storage tanks.  
         [0037]    The tabs  20  that are formed or attached to the ends of the rails  16  may be disposed around the circumference of the post  12 . Portions of each tab  20  are captured and secured between cups of the coupler  18 . The tab  20  on a first end  24  of angled rail  16   a  may be attached at a first angle  22 . The first angle  22  may range from between approximately five and eighty-nine degrees, for example.  
         [0038]    [0038]FIG. 4 depicts the angled rail  16   a  connected between two couplings  18 . The tab  20  on a second end  26  of the angled rail  16   a  may be secured to the angled rail  16   a  at a second angle  28  that may be approximately similar to the first angle  22 . If the first angle  22  is the same as the second angle  28 , the rails  16  of other scaffold sections will remain generally parallel or perpendicular to each other. As a result, the angled rail  16   a  allows square or rectangular sections of scaffolding to be safely joined together at angles other than ninety degrees. Additionally, the tabs  20  and the lengths of angled rails  16   a  may be designed to build the scaffolding system  10  to conform to the contours of many different structures.  
         [0039]    FIGS.  5 - 7  depict the operation of the coupling  18 . FIG. 5 depicts four rails  16  that intersect at the post  12 . The tabs  20  of the rails  16  may be evenly disposed around the circumference of post  12 . The coupling  18  may have an upper section  18   a  and a lower section  18   b , which are generally, for example, conical collars that are disposed around the post  12 . The tabs  20  of the rails  16  may fit into the lower section  18   b  and be held against the post  12 , as depicted in FIG. 6. Then, as depicted in FIG. 7, the upper section  18   a  may be secured over the tops of the tabs  20 . The upper section  18   a  may have a locking mechanism that rotates to lock the tabs  20  against the post  12 , which stabilizes the scaffold system  10 . In this particular embodiment, the tabs  20  are more securely held in place by friction between the tabs  20  and the post  12 . Other methods and systems of securing the rails  16  to the post  12  using the coupling  18  will be apparent to those having ordinary skill in the art of scaffolding.  
         [0040]    [0040]FIG. 8 depicts a scaffold system  10  having a guard rail panel  30 . The guard rail panel  30  may have an upper brace  32  and a lower brace  34 , which span between two posts  12 . A bridging member  36  may connect between the upper brace  32  and the lower brace  34 . The upper brace  32  and lower brace  34  may serve to provide extra safety to workers on the scaffold system  10 . The bridging member  36  adds rigidity to the guard rail panel  30  and also may prevent workers and equipment from falling through the upper brace  32  and the lower brace  34 .  
         [0041]    The upper brace  32  and the lower brace  34  may be connected to the posts  12  by the same method used to connect the rails  16  to the posts  12 . Tabs  20  may be attached to the ends of the upper brace  32  and the lower brace  34 . The upper brace  32  and the lower brace  34  may then be attached to the posts  12  by the couplings  18 . The height of the guard rail panel  30  may be adjusted relative to a platform  38 . Different heights may be required according to the type of work, the dimensions of the structure or the height of the workers.  
         [0042]    [0042]FIG. 9 is a perspective view of the scaffolding system incorporating certain embodiments of the present invention. In addition to guardrails  30  and platform  38  shown in FIG. 8, this embodiment incorporates a spring-loaded safety gate  34  and safety ladder  36  to facilitate safe movement of workers from platform  38  to other portions of the scaffold. In contrast to the method of attachment of rails  16  and guard rail panel  30  described above, safety gate  34  and safety ladder  36  are attached to posts  12  using, for example, mounting clamps  35  and  39 , respectively.  
         [0043]    [0043]FIGS. 10 and 11 are detail views of a mounting clamp  39  of the scaffolding system incorporating certain embodiments of the present invention. Mounting clamp  39  includes strut  40 , inner jaw  42 , outer jaw  44 , threaded shank  46 , and nut  48 . In FIG. 10, clamp  39  is shown fastened to post  12 . In various embodiments, clamp  39  may be fastened to ladder  36  or other portions of the scaffold, depending on the application. In FIG. 11, mounting clamp  39  is shown in its open condition, ready to receive post  12  and be fastened to it.  
         [0044]    In order for mounting clamp  39  to be secured to post  12 , mounting clamp  39  must first be disposed in the open position shown in FIG. 11. Once mounting clamp  39  is placed in the open position, the inner jaw  42 , which is sized to receive post  12 , can be moved into position around post  12 . After inner jaw  42  is placed around post  12 , outer jaw  44  is moved into position on the other side of post  12 , thereby completely capturing post  12  between inner jaw  42  and outer jaw  44 . The final steps in securing mounting clamp  39  to post  12  are to swing threaded shank  46  into position and to tighten nut  48 , thereby securely fastening mounting clamp  39  around post  12 . The process is the same for fastening ladder  36 .  
         [0045]    [0045]FIG. 12 is a perspective view of a scaffold  60  incorporating certain embodiments of the present invention. As with the above-described scaffolds, scaffold  60  of FIG. 12 comprises a series of vertical posts  12  rising from base levelers  14  tied together with horizontal rails  16  at couplers  18 . In contrast to the above-described scaffolds, however, scaffold  60  is constructed in such a manner that it changes angular direction. Scaffold  60  would be useful, for example, where it is desirable to access two faces of a building at their intersection corner. Traditional scaffolding is designed for traditional building shapes, which generally incorporate right angles at the intersection of walls. Modern building designs, however, commonly make use of odd angles and curves, necessitating creative scaffolding solutions such as the present invention.  
         [0046]    Certain prior designs have been developed which allow for construction of scaffolds having turns and intersections of greater than or less than 90 degrees, but such designs generally make use of adjustable sliding or rotating joints, or a combination of both, to allow for angles other than 90 degrees. Although these designs are adequate in certain situations, it is known that the adjustable joints can be a safety hazard, as they are a weak point in the design.  
         [0047]    The present invention does not use pivoting or sliding joints. The present invention uses rails  64  having fixed lengths and mounting faces disposed at predetermined, fixed angles. The use of rails  64  having fixed, rather than adjustable, angles allows the construction of rails  64  to be much stronger, and therefore safer, than prior designs.  
         [0048]    The use of rails  64  in the construction of an angled scaffold such as scaffold  60  can be clearly seen in FIG. 12. The portions of scaffold  60  to the right and left of rails  64  make use of rails  16  in a conventional box arrangement, such as is suitable for building along a flat, straight wall. In contrast, the center section of scaffold  60  makes use of angled rails  64  and shortened rails  62  in order to effectuate an angle difference between the left and right sides of scaffold  60 .  
         [0049]    A side view of one embodiment of a guard rail panel  30  of the present invention is shown in FIG. 13. Guard rail panel  30  includes upper brace  32  and lower brace  34 . In the embodiment shown in FIG. 13, bridging members  36  connect the upper brace  32  to the lower brace  34 . In the embodiment shown in FIG. 13, each of upper and lower braces  32  and  34  includes a mounting flange  72  comprising upper and lower tabs  20 , to facilitate coupling to posts  12  at couplings  18 .  
         [0050]    The upper brace  32  and lower brace  34  may serve to provide extra safety to workers on the scaffold system  10 . The bridging members  36  add rigidity to the guard rail panel  30  and also may prevent workers and equipment from falling through the space between upper brace  32  and lower brace  34 .  
         [0051]    The upper brace  32  and the lower brace  34  may be connected to the posts  12  by the same method used to connect the rails  16  to the posts  12 . The upper brace  32  and the lower brace  34  may then be attached to the posts  12  by couplings  18 . In certain embodiments, the height of the guard rail panel  30  may be adjusted relative to a platform  38 . Different heights may be required according to the type of work, the dimensions of the structure or the height of the workers.  
         [0052]    A side view of a second embodiment of a guard rail panel of the present invention is shown in FIG. 14 and generally designated  80 . Guard rail panel  80  has the same basic structure as guard rail panel  30  described above. In contrast to guard rail panel  30 , however, guard rail panel  80  incorporates a set of diagonal bridging members  82  in addition to vertical bridging members  36 . Diagonal bridging members  82  serve to strengthen and stiffen guard rail panel  80 . In the embodiment shown in FIG. 13, diagonal bridging members  82  are disposed to carry vertical loads applied in the center region of guard rail panel  80  to the outside corners of the structure, where guard rail panel  80  is stronger.  
         [0053]    A side view of a third embodiment of a guard rail panel of the present invention is shown in FIG. 15 and generally designated  90 . Guard rail panel  90  incorporates the basic structure of guard rail panels  30  and  80 , with additional structural reinforcement to facilitate use in applications requiring longer unsupported spans or higher load-carrying capacity. As seen in FIG. 15, guard rail panel  90  incorporates a reinforcing rail  92  and reinforcing column  94  attached to the top of upper brace  32 . The additional strength and stiffness provided by reinforcing rail  92  and reinforcing column  94  allow guard rail panel  90  to be used in more demanding applications than guard rail panels  30  and  80 .  
         [0054]    A side view of a safety gate of the present invention is shown in FIG. 16 generally designated  100 . Safety gate  100  includes hinge  102  and gate frame  104 . Gate frame  104  is mounted to, and swings around, hinge pivot rod  106 . Safety gate  100  can be mounted to scaffolding in any of a manner of methods and structures known to those of skill in the art of mechanical structures. The embodiment shown in FIG. 16 is designed to be mounted to a vertical member of a scaffold by means of mounting clamp  108 . The embodiment shown in FIG. 16 is designed to be self-closing due to the action of closing spring  110  on hinge  102 , which acts to swing gate frame  104  closed in the absence of an opening force.  
         [0055]    [0055]FIG. 17 is a side view of a supplemental vertical strut, generally designated  120 , according to one embodiment of the present invention. Supplemental vertical strut  120  includes post  122 , one or more cup-type couplings  124 , and one or more mounting clamps  126 . Suuplemental vertical strut  120  can be used to provide a vertical structural member when needed at a point along a rail  16  in between posts  12 . Supplemental vertical strut  120  can be used, for example, to create a “doorway” opening with guard rail panel on either side. Such a doorway could be left open, or could be provided with a safety gate such as safety gate  100 , for example. Supplemental vertical strut  120  is shown with a single mounting clamp  126  installed, but most embodiments will incorporate one mounting clamp at each end, so as to be secured to an upper and lower horizontal rail.  
         [0056]    A detail view of an angled rail  64  can be seen in FIG. 18. As shown in FIG. 18, angled rail  64  has a center section  132  having a length L, and end sections  134  and  136 , each disposed at an angle A from the principal axis of center section  132 . Each of end sections  134  and  136  incorporates upper and lower tabs, as described elsewhere for connection to cup-type locking couplers. The length L of the center section  132  and angle A of end sections  134  and  136  will vary depending upon the application. One embodiment of the present invention incorporates angled rails  64  having a length L of 28.5 inches and angle A of 22.5 degrees to accommodate, for example, a 45-degree angle in the scaffold structure.  
         [0057]    The embodiments and examples set forth herein are presented to best explain the present invention and its practical application and to thereby enable those skilled in the art to make and utilize the invention. Those skilled in the art, however, will recognize that the foregoing description and examples have been presented for the purpose of illustration and example only. Other variations and modifications of the present invention will be apparent to those of skill in the art, and it is the intent of the appended claims that such variations and modifications be covered. The description as set forth is not intended to be exhaustive or to limit the scope of the invention. Many modifications and variations are possible in light of the above teaching without departing from the spirit and scope of the following claims. It is contemplated that the use of the present invention can involve components having different characteristics. It is intended that the scope of the present invention be defined by the claims appended hereto, giving full cognizance to equivalents in all respects.