Abstract:
The present application provides an effective cooperation of scaffold planks and ledger members of a scaffold system to provide a work platform that is adaptable to different requirements and configurations. In one embodiment a rail portion of a scaffold plank is received in an upwardly opening U-shaped cavity of a ledger. In this way a portion of the work surface over laps with the ledger.

Description:
FIELD OF THE INVENTION 
       [0001]    The present application relates to scaffolding systems and in particular relates to scaffold planks and providing an effective work platform defined by cooperating scaffold planks. 
       BACKGROUND OF THE INVENTION 
       [0002]    Scaffold systems include vertical upright members with a series of mechanical connections (rosettes, cups or other fixed structures) at selected points along the length of the uprights. These mechanical connections releasably engage ledgers, transoms and bracing members to provide a stable frame type structure. Typically the vertical uprights are spaced according to a predetermined grid pattern. The ledgers, transoms, braces and scaffold planks are of a length and width appropriate to partially define and maintain the predetermined grid and modularity of the system. A typical scaffolding system will include perhaps three different lengths of ledgers allowing vertical uprights to be placed at three different upright locations. This provides grid flexibility for accommodating scaffolding around or adjacent to different existing structures. In many scaffolding systems the transom members and the ledger members are of the same construction thereby reducing the number of separate components of the system. 
         [0003]    Scaffold planks typically include end caps for engaging a ledger member and supporting the scaffold plank between two parallel ledgers by means of end caps or hooks at opposite ends of the scaffold plank. A scaffold plank can include a wood body but more commonly is now manufactured as a roll formed metal body. These roll formed metal bodies include generally flat top surface with downwardly extending rail portions at opposite edges of the plank. The scaffold planks cooperate to form a work platform between the vertical uprights. 
         [0004]    More recently, it is been found desirable to coordinate the scaffold plank such that a more continuous work platform is defined between four uprights of the scaffolding system that define a grid. 
         [0005]    In addition, it is desirable to have scaffold planks within a cell of the grid cooperate to provide a work surface around a structure such as a chimney or pipes extending through the work surface. 
       SUMMARY OF THE INVENTION 
       [0006]    A modular scaffold system, according to the present invention has a series of upright members connected by a series of ledger members to define a rectangular grid having rectangular cells between  4  cooperating upright members. The scaffold system further includes a series of scaffold planks extending between two opposed parallel ledgers to define at least a portion of a work platform covering at least one of said rectangular cells with endcaps of said scaffold planks at the ends thereof including downwardly extending members received in or on one of said ledgers and at least two of said scaffold planks including downwardly extending rail portions received in opposed parallel ledger members of said rectangular cell. 
         [0007]    The present invention provides a scaffold plank system that cooperates with an upwardly opening U-shaped ledger member where a portion of the rail of the scaffold plank can be located within the U-shaped ledger. Essentially, the rail portion will occupy less than 50% of the width of the U-shaped member and it is possible to have two scaffold planks on opposite sides of the ledger with a rail portion of each scaffold plank located in the U-shaped ledger. This arrangement provides flexibility in providing effective coverage of the scaffold planks across a cell of the grid. 
         [0008]    According to an aspect of the invention the scaffold planks having said rail portions received in a ledger member covering less than 50 percent of a width of said ledger members. 
         [0009]    In a further aspect of the invention the ledger members are each capable of receiving two rail portions of adjacent scaffold planks on opposite sides of a centerline of the respective ledger member. 
         [0010]    In yet a further aspect of the invention each scaffold plank at the ends thereof includes notched corners allowing side edges of scaffold planks to be placed near the centerline between connected vertical members where the notched corners accommodate part of the periphery of said upright members. 
         [0011]    According to an aspect of the invention the ledger members have an upwardly opening U shaped body extending between ledger heads adapted to connect with any of a series of connection points provided on each upright. 
         [0012]    In a preferred aspect of the invention each scaffold plank includes a rolled metal body portion extending between endcaps of said scaffold plank. 
         [0013]    In yet a further aspect of the invention the U shaped body of at least some of said ledgers include 3 pairs opposed notches, with each pair of notches adapted to receive a bracket used to connect with ledgers at an intermediate point in the length of the ledger member. 
       BRIEF DESCRIPTION OF THE DRAWINGS 
       [0014]    Preferred embodiments of the invention are shown in the drawings, wherein: 
         [0015]      FIG. 1  is a partial perspective view showing a series of uprights and scaffold planks secured to ledger members connecting the vertical members; 
         [0016]      FIG. 2  is a prospective view of a single ledger member and a scaffold plank about to be attached to the ledger; 
         [0017]      FIG. 3  is a partial perspective view of a U-shaped ledger having a rail of a scaffold plank located within the ledger and an end cap of an adjacent scaffold plank being attached to the opposite side of the U-shaped ledger; 
         [0018]      FIG. 4  is a partial perspective view of a U-shaped ledger having rails of two adjacent scaffold planks located in the ledger; and 
         [0019]      FIG. 5  is a perspective view of a modified scaffold plank having a projecting flange on one side of the scaffold plank. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    The scaffold system  2  shown in  FIG. 1  includes a series of uprights  4  having a spaced rosettes  5  or other connection nodes at predetermined positions in the length of the upright. These spaced rosettes are positioned on the vertical upright to define a particular vertical modularity of the scaffold system. Adjustable feet typically have a screw type adjustment and are received in the bottom of the upright to appropriate position each upright. 
         [0021]    The uprights  4  are interconnected by ledgers  6  with some of these ledgers being parallel and other ledgers being perpendicular. In this case releasable ledger heads  8  connect with the rosettes  5  of the uprights. The ledgers  6  are designed act as ledgers and transoms and can extend in any direction based on the rosette. The preferred ledger  6  is shown in  FIGS. 2 and 3  and has a U-shaped elongate body portion which is open upwardly and is designed to engage with the end caps of the scaffold planks  12  or to receive a rail portion  26  of a scaffold plank  12  as shown in  FIG. 3 . 
         [0022]    Each of the scaffold planks  12  include an end cap  20  having a downwardly extending flange  21  for providing a hook type engagement with an edge of a ledger member. It can be seen that the end caps also include notched corners  18  which allow the end cap to be placed in close engagement with a side of the upright as clearly shown in  FIG. 1 . In this way a scaffold plank extending between two uprights can have the longitudinal side edge of the scaffold plank at approximately the centerline passing through the uprights. In some scaffold systems the scaffold planks can merely come to the outer edge of the uprights however the notched corners  18  allow positioning of a portion of the scaffold plank between the uprights such that a portion of the top surface of the scaffold plank is above and partially covers the ledger. 
         [0023]      FIG. 1  shows a series of scaffold planks  12  forming a work surface covering a cell of the grid between vertical uprights of the scaffold system with three vertical uprights shown. The scaffold planks  12  essentially provide full coverage of the individual cell and four such planks are shown with the two outside planks having rail portions received in the underlying ledger and the intermediate two planks in close proximity to the other scaffold planks to effectively define a non-interrupted work surface. There may be a slight gap shown as  28  between vertical uprights and this gap is typically the size of a wedged member used to secure a ledger head of the ledger to the rosette. It is also possible for the scaffold planks to cover such wedges shown as  29  in  FIG. 2  or have the top surface of the wedge of the ledger head to be flush with the level of the work surface. The principle is to have a work platform that is less prone to small parts falling through the work platform and to avoid trip hazards associated with the work surface. Some small gaps (less than half of an inch) between planks may be acceptable. The present design essentially provides a continuous work surface without trip hazards. 
         [0024]    It is also desirable in modular scaffolding systems to allow planks to be installed in different orientations. The scaffold plank  12 a is shown engaging the adjacent cell and is in a perpendicular orientation relative to the initial planks  12 . A large open cavity  31  is shown which is partially bordered by the scaffold planks  12   d  and  12   c.  These scaffold planks are supported by the ledger  6   a  as well as an intermediate ledger  6   b  which is supported by the ledgers extending between uprights. Thus the ledger  6   b  is supported by and extends between two opposed ledgers at a position intermediate the length of the opposed ledgers. As shown in  FIG. 2 , the ledger  6  includes three pairs of notches  7  on opposite sides of the ledger which receive a saddle type bracket that allows for securement of a cross ledger at positions intermediate the length of the ledger. These saddle type brackets form a rosette like connection at positions intermediate the ends of the ledger. In this way any ledger can be used to provide an intermediate support for engaging an end of a ledger. 
         [0025]      FIG. 3  shows a particular cooperation of the scaffold plank  12   d  with the ledger  6   c.  The side rail  26  is received within the ledger  6   c  and the scaffold plank  12   d  covers a portion of the ledger. The wedge  29  is below the top surface of the scaffold plank and is visible between two the planks. The downwardly projecting flange  21  of scaffold plank end cap  20   a  is received in the U-shaped ledger  6   c.  Therefore  FIG. 3  shows scaffold plank  12   d  extending in one direction with its rail portion  26  received within the U-shaped ledger  6   c  and the endcap  20   a  of a second scaffold plank, extending in a perpendicular direction, is also received within the U-shaped ledger. 
         [0026]    The particular structure of the ledger and the cooperation of the ledger with the scaffold plank, allows the scaffold planks to be secured across a scaffold grid cell with each end caps effectively covering the ledger to the approximate centerline of the U-shaped cavity. Opposed endcaps of scaffold planks supported to the opposite side of the ledger to cover the opposite side of the U shaped cavity. It is also possible to have a scaffold plank with a rail portion received within the U-shaped ledger covering the opposite side of the U shaped cavity as shown in  FIG. 3 . Therefore endcaps and rail portions individually or in combination can cooperate to cover the U shaped cavity. This arrangement allows the installer to selectively orientate the scaffold planks to define the work area and provide coverage of at least intermediate ledgers having scaffold planks either side thereof. The orientation of the scaffold planks is variable and the ledgers and scaffold planks can be provided in different modular lengths. 
         [0027]    The partial perspective view of  FIG. 4  shows the ledger  6   d  secured to the upright  4  by means of the ledger head  8  engaging the rosette  5  and secured thereto by the wedge  19 . The endcap  20   e  of scaffold plank  12   e  engages a ledger (not visible) extending to one side of the upright  4  with endcap  20   f  of scaffold plank  12   f  engaging a further ledger (not visible) on the opposite side of the upright  4 . The side rail portions  26   e  and  26   f  are received within the U-shaped ledger and can generally be close to the centerline between uprights due to the notched corners  18  accommodating the upright  4 . The planks  12   e  and  12   f  are primarily or sufficiently supported by the endcaps at opposite ends of the planks and are not relying on support by the ledger  6   d . The modified ledger  6   d  also includes opposed pairs of notches  7  (only one shown) that allow a saddle bracket to be placed on a ledger as previously described for providing a ledger to ledger connection as may be required to provide provide scaffold planks bordering an opening within a grid cell or to selectively locate planks within a grid cell as may be required to address an onsite condition or structure. 
         [0028]    As shown in  FIG. 4  the endcaps  20   e  and  20   f  cooperate to partially cover supporting ledgers and scaffold planks  12   e  and  12   f  have their rail portions received in ledger  6   d  to partially cover the open cavity of the ledger. This arrangement is helpful in reducing the likelihood of small parts falling through a gap in the work platform surface and in providing flexibility in configuring work platforms. 
         [0029]    The upwardly opening U-shaped ledger also tends to capture small parts from passing through the work surface. 
         [0030]    The scaffold plank as shown in  FIG. 5  is a modified arrangement and is shown as  54 . In this scaffold plank, one side edge of the scaffold plank has a projecting flange  52 . The endcaps can also include cooperating portions such that the projecting flange extends along the length of the scaffold plank. The opposite edge  58  of the scaffold plank is generally perpendicular. This plank can be used with one edge received within a U shaped cavity of a ledger. In some cases it may be desirable to have the rail portion with the projecting flange received within a ledger member to more fully cover the U-shaped opening. All planks could be of this modified structure or combinations of the different scaffold plank structures can be used. 
         [0031]    With the embodiments shown in  FIGS. 1 through 3  the scaffold plank will typically have both sides of the plank extending downwardly in a generally perpendicular manner. With roll formed structures corners are typically rounded. It is very common to have a small projecting bead and a small projecting bead at the base of the rail portion to provide additional strength to the roll formed body portion. With the present system and the ability of the rail to be received within the U-shaped channel, it is desirable to keep the width of the rail portion relatively narrow while still providing the necessary strength. The narrow rail portion is received within the U-shaped channel and in a preferred structure the width of the U-shaped ledger is less than about 3 inches. 
         [0032]    It can be appreciated that variations can be made to this design that allow the rail portion of the scaffold plank to be received within a U-shaped channel and this arrangement can provide direct support for the scaffold plank along that edge but it need not do so. The scaffold planks are designed for end cap support and do not require indirect support by the rail portion within the U-shaped ledger. 
         [0033]    Preferred embodiments of the present invention have been described herein in detail, it will be appreciated that variations may be made thereto while still operating in the manner of the disclosed invention.