Patent Publication Number: US-2009218166-A1

Title: Scaffold auxiliary shelf

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This patent application is related to and claims priority from U.S. Provisional Patent Application Ser. No. 61/032,098 filed Feb. 28, 2008. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates, in general, to accessories for scaffolds and, more particularly, this invention relates to a removable and adjustable-height work shelf for mobile scaffolds. 
     BACKGROUND OF THE INVENTION 
     Prior to the conception and development of the present invention, construction workers, such as ceiling installers, have used portable scaffolds with wheels to elevate them as needed to reach where they were working. For the case of ceiling installation, the installer must pick a tile off a pile then lift it overhead to put into place while standing on the platform of a mobile scaffold. As the pile is depleted, the installer must reach down further and further to grasp the next tile to be installed. One example of the type of scaffold can be found in U.S. Pat. No. 6,863,155, which discloses a remote braking system for such a scaffold. As shown, there are four vertically extending corner posts with castors on the floor and an elevated platform for the user to stand on to reach where necessary. Apertures in the corner posts are axially spaced and accept pins or rods that secure the platform level and at a desired height. This common type used in the construction trades is what is typically called a “Baker”, or baker-type and it has four vertical corner posts with a multitude of slots or apertures in each. Other designs have rungs from which the platform is hung. Still others have angle irons for corner posts with slots spaced up and down the length. 
     Testa in U.S. Pat. No. 5,622,463 disclosed a cutting table for a scaffold, wherein the table is sloped and extends away from one end of the scaffold. Similarly, Allen in U.S. Pat. No. 5,158,023 disclosed a scaffold table that extends outward from one end with adjustable legs that extend at an angle back to the scaffold frame. The top edge of the Allen table attaches only to horizontal rungs on the scaffold, which severely limits the number of heights that are achievable while maintaining a horizontal table surface. U.S. Pat. No. 7,353,911 also discloses a scaffold shelf that attaches to the horizontal crossbars and extends away from the user. Two-legged portable tables for attachment to automobile trunks were disclosed in U.S. Pat. Nos. 4,452,151 and 5,730,066. Both of these tables attach to the lower horizontal edge of a car trunk opening. 
     Markovich in U.S. Pat. No. 6,955,242 discloses a retractable scaffold support bracket that is triangular shaped and meant to be mounted on a concrete wall form. In addition, Mitchell is U.S. Pat. No. 6,116,163 discloses an adjustable work table for scaffolding that includes triangular support members. None of the latter three tables or shelves transfer any of the load weight to the main platform of the scaffold; therefore, a thicker and heavier construction is likely for support of the same amount of load weight. 
     SUMMARY OF THE INVENTION 
     The present invention provides an auxiliary shelf attachment for mobile scaffolds having a platform member and at least two vertically extending posts with multiple axially spaced apertures, wherein the shelf attachment includes a substantially planar shelf member having a proximal edge, two side edges, and a distal edge adjacent which two hinged legs are secured. Also included is an attachment means disposed adjacent corners of each of the two side edges and the proximal edge for removable attachment of the planar shelf member to two of the elongated posts. 
     OBJECTS OF THE INVENTION 
     It is, therefore, one of the primary objects of the present invention to provide a support shelf to make items conveniently available to users of mobile scaffolds. 
     Another object of the present invention is to provide a horizontal support shelf for scaffolds that can be adjusted in height relative to the scaffold platform. 
     Still another object of the present invention is to provide a lightweight support shelf that can support a sizeable load at an elevated position above the standing platform of a scaffold. 
     Yet another object of the present invention is to provide a lightweight convenient support shelf for scaffolds that can fold away when not needed. 
     An additional object of the present invention is to provide a convenient and time-saving device for ceiling installers, painters, plumbers and other construction workers. 
     In addition to the various objects and advantages of the present invention described with some degree of specificity above, it should be obvious that additional objects and advantages of the present invention will become more readily apparent to those persons who are skilled in the relevant art from the following more detailed description of the invention, particularly, when such description is taken in conjunction with the attached drawing figures and with the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the present invention attached to a mobile scaffold. 
         FIG. 2  provides a perspective view of a preferred embodiment of the present invention. 
         FIG. 3  presents a bottom perspective view of a preferred embodiment of the present invention. 
         FIG. 4  provides a partial perspective detail view of an alternative embodiment of the present invention. 
         FIG. 5  is a perspective view of a frame member portion of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF A PRESENTLY PREFERRED AND VARIOUS ALTERNATIVE EMBODIMENTS OF THE INVENTION 
     Prior to proceeding to the more detailed description of the present invention it should be noted that, for the sake of clarity and understanding, identical components which have identical functions have been identified with identical reference numerals throughout the several views illustrated in the drawing figures. 
     Referring initially to  FIG. 1 , the adjustable shelf of the present invention, generally indicated by  10 , is shown deployed on a mobile scaffold, generally indicated by  30 . The scaffold has a platform member or walkboard  32 , elongated corner posts  34 , and castors  36  at the bottom of each post  34 . The two or four posts  34  will typically have multiple spaced-apart slots or apertures  38  that facilitate securing the platform member to the posts  34  at the desired height. The present invention adds the improvement of a support shelf  10  consisting of a substantially planar and substantially rectangular top panel  12  having a proximal edge that attaches to the posts  34  with the deck substantially horizontal, and a distal edge  24  that is connected, preferably hingedly, to two adjacent legs  14  with feet resting on the walkboard or platform  32 . The legs  14  may be telescopically adjustable in length so that the panel  12  can be maintained essentially horizontal for use when installed into any two of a range of slots or apertures  38  in the posts  34 . It may be one inverted U-shaped member, as shown, or two independent legs as shown in  FIG. 2  and  FIG. 3 . A typical use for the present invention  10  is with a mobile scaffold  30  that is used by an installer of items such as ceiling tiles. Tiles can be stacked on the shelf top panel  12  at an adjustable height convenient to the user. 
     Referring next to  FIG. 2 , the shelf member  10  is shown alone in more detail. The planar top panel  12  has a proximal edge  22  and a distal edge  24  that is connected to adjacent legs  14 . The legs  14  have a length-adjustment means  16  that enables the top panel  12  to be maintained in a substantially horizontal disposition when connected for use at the proximal edge to the posts of the scaffold. Near the corners of the proximal edge  22  and the side edges  17  are extensions or hooks  18  that engage with the slots or apertures at the desired position on the vertical posts as shown in  FIG. 1 . The hooks  18  may be extensions of side rails  17  as shown secured to the side edges with fasteners  28 , or alternatively integral with the side rails  17 . The hooks may instead be fastened directly to the planar top panel  12 . The legs  14  are connected to or support the shelf member  12  adjacent the distal edge  24  with an optional hinge mechanism  26  so that the shelf unit  10  can be folded to a more compact arrangement when not in use. Optionally, the legs may be removable by sliding into slightly wider sleeves. The lower part of the legs  19  telescopically extend out, within a practical range, to permit the height of the shelf  12  to be adjusted, and a locking mechanism  16  maintains the overall length of leg sections  14  plus  19 . For added utility, apertures  20  in the shelf  12  may be added for the holding of tools when desired. 
       FIG. 3  provides a perspective view from the underside of a preferred embodiment of the present invention with the non-adjusting legs  14  alternative. The shelf top panel  12  is supported on L-shaped frame members  17 ,  22 , and  24 . The rear frame member  24  also attaches to the leg hinges  27  that also are fastened to the legs  14  near the top end of each. The legs  14  are connected in the lower zone to a brace  29 . Protruding from the side members  17  adjacent the corners with the frame member  22  are attachment hooks or rods  18 . These slide into notches or round holes in the vertical posts of the companion scaffold with witch it will be used, as shown in  FIG. 1 . 
       FIG. 4  is a perspective detail view of a corner portion of the present invention with an alternative embodiment of the means for attaching to the vertical posts. The edge frame members  17  and  22  support the planar shelf member  12  as shown elsewhere. On one corner, an attachment rod  42  is secured perpendicular to a sliding bar  40  which is loosely engaged in the slot  43  in sidewall frame member  17 . Adjacent an end opposite the rod  42  is a pin or bolt  46  which can slide in slot  45  in the proximal frame member  22 . The rod  42  additionally has a notch  48  and/or an aperture  49  through which a holding pin can be inserted once the rod  42  is in place through the vertical scaffold member. 
       FIG. 5  is a perspective view of a frame member portion of the present invention. There are two L-shaped sidewalls  17  with end attachment extensions  18 . Typically, an extension  18  will be a hook, or a notched pin or bar that fits into and removably hook into notches or apertures on vertical corner posts of a mobile or rolling scaffold. The proximal edge  22  member is also an L-shaped elongated fixedly attached to the sidewalls  17  adjacent the extensions  18 . The distal frame member  24  is also L-shaped but with a wider horizontal flange portion. An optional handle  50  may be attached to the distal frame member  24 . 
     While a presently preferred embodiment and alternative embodiments of the present invention have been described in sufficient detail above to enable a person skilled in the relevant art to make and use the same, it should be obvious that various other adaptations and modifications can be envisioned by those persons skilled in such art without departing from either the spirit of the invention or the scope of the appended claims.