Abstract:
A size-adjustable platform for scaffolding comprises a plurality of overlapping sections extending from a central core, the sections including separate panels reciprocable with respect to the central core whereby the extent of the platform from the central core may be varied in size upon actuation of a ram or equivalent to cater for variable dimensions.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    Benefit of U.S. Provisional Application for Patent Ser. No. 60/929,044 filed on Jun. 8, 2007, is hereby claimed. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to scaffolding, and is more particularly concerned with a size-adjustable platform for use therewith. 
       BACKGROUND OF THE INVENTION 
       [0003]    It is known in the art of scaffolding to have a work platform that is displaceable in a translational manner, towards and away from an adjacent wall surface, as shown in U.S. Pat. No. 6,095,285 of one of the present inventors and granted on Aug. 1, 2000. 
         [0004]    However, this type of displaceable platform leaves an area uncovered when being displaced, which is not well suited for application where the platform needs to be selectively either enlarged or reduced in size to adapt to the varying available space between the supporting tower structure and the adjacent wall surface to be worked on and along which the platform is being displaced. This is especially applicable when the platform is at least partially annular in shape, such as when located inside a furnace tower, chimney, silo or the like with a constantly varying diameter along its axial length, for the cleaning and/or maintenance and/or construction of the inside wall thereof. 
         [0005]    Accordingly, there is a need for an improved work platform for scaffolding and the like. 
       SUMMARY OF THE INVENTION 
       [0006]    It is therefore a general object of the present invention to provide an improved work platform for scaffolding and the like. 
         [0007]    An advantage of the present invention is that the work platform is expandable to follow the contour and/or profile of a surface, including obstacles and/or discontinuities thereof, along which the platform is being rectilinearly displaced. 
         [0008]    Another advantage of the present invention is that the work platform is radially and telescopically expandable with a plurality of radial sections. 
         [0009]    A further advantage of the present invention is that the work platform is made of a plurality of adjacent circumferential sections independently expandable and retractable with respect to one another. 
         [0010]    A further advantage of the present invention is that the work platform is easily and quickly mounted on and dismounted from a site. 
         [0011]    According to a first aspect of the invention there is provided a size-adjustable platform for scaffolding comprising a non-expandable portion securable to a movable part of the scaffolding, an expandable section releasably mounted on the non-expandable portion, and an actuating mechanism adapted selectively to move the said expandable section relative to the non-expandable portion thereby to adjust the size of the platform. 
         [0012]    The size-adjustable platform may be of annular shape for surrounding scaffolding erected vertically at the centre of the platform. 
         [0013]    The size-adjustable platform may in the alternative be of rectilinear shape extending orthogonally from scaffolding erected at a margin of the platform. 
         [0014]    According to a further aspect of the present invention, there is provided a size-adjustable platform for scaffolding, comprising at least a fixed first panel and a movable second panel mounted adjacent one another, and an actuating mechanism connected to the first and second panels and adapted to selectively reciprocate the second panel with respect to the first panel thereby to expand or reduce a size of the platform. 
         [0015]    The platform may include a third panel movably mounted on the second panel opposite the first panel, and a synchronizing mechanism connected to the first, second and third panels to synchronize displacement of the third panel relative to the second panel with the displacement of the second panel relative to the first panel. 
         [0016]    The platform may conveniently be of annular form and each panel may be of segmental shape with the second panel overlying the first and when provided the third panel overlying the second. 
         [0017]    Advantageously the third or outer circumferential panels are arranged in pairs of sections, and each pair includes an upper circumferential section and a lower circumferential section secured one to the other side-by-side. Each circumferential section preferably includes a plurality of radially and telescopically expandable radial sections, each adjacent pair being independently expandable one from the other. 
         [0018]    Adjacent pairs of outer circumferential panels overlap one another in alternating manner with each upper circumferential section being adjacent two lower circumferential sections and vice-versa, the arrangement being such that in either extended or retracted mode a continuity of surface is achieved. 
         [0019]    The actuating mechanism may be hydraulically or pneumatically powered and may thus comprise an actuating ram interconnecting the first and second panels. In an alternative embodiment a screw drive may be provided to effect reciprocating relative movement between the panels. 
         [0020]    The synchronizing mechanism is associated with the actuating mechanism and comprises for example chains interconnecting the first and third panels, the chains being reeved over appropriate sprockets associated with the second panels. 
         [0021]    The synchronizing mechanism may further incorporate telescoping beams which slide within one another and are mounted beneath respective panels, whereby upon actuation of the actuating mechanism relative movement is achieved in synchrony such that relative movement is smooth with the outer panel moving twice as fast as the middle panel in relation to the first fixed panel. 
         [0022]    A controller for the actuating mechanism is advantageously provided on the non-extendable part of the platform. 
         [0023]    It will be understood that whilst the specific embodiment of the invention has been defined in terms of an annular platform, a rectilinearly-shaped platform also falls within the scope of the present invention. Other objects and advantages of the present invention will become apparent from a careful reading of the detailed description provided herein, with appropriate reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    Further aspects and advantages of the present invention will become better understood with reference to the description in association with the following Figures, in which similar references used in different Figures denote similar components, wherein: 
           [0025]      FIG. 1  is a top perspective view of a scaffolding assembly having a work platform in accordance with an embodiment of the present invention; 
           [0026]      FIG. 2  is an enlarged perspective view taken along line  2  of  FIG. 1 , showing a pair of platform circumferential sections with their respective three radial sections in a fully extended configuration; 
           [0027]      FIG. 3  is a top plan view of the pair of platform circumferential sections of  FIG. 2 ; 
           [0028]      FIG. 4  is a view similar to  FIG. 3 , showing the pair of platform circumferential sections with their respective three radial sections in a fully retracted configuration; and 
           [0029]      FIG. 5  is a schematic section view taken along line  5 - 5  of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0030]    With reference to the annexed drawings the preferred embodiments of the present invention will be herein described for indicative purpose and by no means as of limitation. 
         [0031]    Reference is now made to  FIG. 1 , there is shown a scaffolding assembly  10  typically centrally and axially mounted inside a large chimney  12  for cleaning or maintenance of the internal wall surface thereof. The scaffolding assembly  10  includes a main tower  14  supported at its base by a structure  16  mounted at the bottom of the chimney  12 , the assembly being typically further secured at its top portion to the chimney structure generally extending through the top opening of the chimney  12 . A main sleeve structure  18  surrounds the main tower  14  and is displaceable therealong and secured thereto at any selected location. A work platform, shown generally as  20 , in accordance with an embodiment of the present invention is releasably mounted onto the sleeve structure  18 , and defines an access opening  22  therethrough to allow for the passage of a secondary sleeve structure  24  with its secondary platform  26  attached thereto being displaceable along a secondary tower  28 , typically secured adjacent to the main tower  14 , via its displacement mechanism  30  (motor cage thereof shown) carried thereby. Both the main and secondary sleeve structures  18 ,  24  have a respective axial slit opening therealong to allow for the passage of the tower-to-tower attachments (not shown) during displacement along their respective towers  14 ,  28 . 
         [0032]    The secondary sleeve structure  24  and platform  26  are generally used as an elevator to carry workers and/or materials to and from the work platform  20 . Similarly, the main sleeve structure  18  carries its own displacement mechanism (not shown). Alternatively, the secondary sleeve structure  24  and platform  26  could also be used as a freight elevator, to carry and displace the main sleeve structure  18  with the work platform  20  to different locations along the main tower  14  where it is secured thereto. In such a case, before displacement of the main sleeve structure  18 , the latter is connected to the secondary sleeve structure  24  before it is disconnected from the main tower  14 , and in reverse when the desired location is reached. 
         [0033]    The access opening  22  extends through a non-expandable portion  32  of the work platform  20  releasably secured to the main sleeve  18 . The work platform  20  includes an expandable section  34  thereof and is releasably mounted onto the non-expandable portion  32 . The expandable portion  34  includes a plurality of adjacent circumferential platform sections  38  oriented towards a wall surface to be worked on such as the chimney internal wall. Each circumferential section  38  is radially expandable in order to allow adjustment of the work platform  20  to the varying section of the chimney  12 . Each circumferential section  38  covers an angular portion of an annular section of the work platform  20 , such that all circumferential sections  38  form an annular shaped outer portion of the platform  20 . 
         [0034]    As shown more specifically in  FIGS. 2 ,  3  and  5 , circumferential sections  38  are typically arranged in pairs  40  for easy assembly of the platform  20 . Each pair  40  includes an upper circumferential section  38   u  and a lower circumferential section  38   l  secured to one another side-by-side. Each circumferential section  38  includes a plurality of radially and telescopically expandable radial sections  42 . Although each circumferential section  38  is independently expandable from each other, the two sections  38   u ,  38   l  of the same pair  40  are arranged and connected to simultaneously expand or retract, independently of any other pair  40 , in order to allow for local discontinuities or non-uniformity of the surrounding section wall of the chimney  12 . 
         [0035]    For each circumferential section  38 , the radial sections  42  thereof (three of which are shown in the figures) are movable relative to each other in a radial direction, with the innermost radial section  42   i  being fixed relative to the adjacent structure  32 . As shown in  FIGS. 2 ,  3  and  5 , the two circumferential sections  38   u ,  38   l  of the pair  40  are shown in a fully extended configuration, with the middle panels  44   m  of the middle radial section  42   m  partially overlapping the corresponding inner panel  44   i , and partially overlapped by the outer panel  44   o  of the corresponding outermost radial section  42   o  (the covered outlines being shown in dotted lines in  FIG. 3 ). Similarly, middle and outer panels  44   m ,  44   o  of the upper circumferential section  38   u  partially overlap the corresponding panels of the adjacent lower circumferential sections  38   l , the one of the same pair  40  as well as the one of the adjacent pair  40 , such that the circumferential sections  38  alternate as upper and lower sections when assembled, as in  FIG. 1  (with each upper circumferential section  38   u  adjacent two lower circumferential sections  38   l , and vice-versa). 
         [0036]      FIG. 4  shows the two circumferential sections  38   u ,  38   l  of the pair  40  in a fully retracted configuration, with most of the inner panels  44   i  being covered by the corresponding middle panels  44   m , which are themselves mostly covered by the corresponding outer panels  44   o , as highlighted by the dotted outlines. 
         [0037]    The expansion actuating mechanism  46  of each circumferential section  38  is conveniently a hydraulic ram (although other mechanisms could be considered without deviating from the scope of the present invention) with the cylinder section  48  pivotally connected to a hollow inner beam  52   i  mounted under the inner panel  44   i , and the piston section  50  connected to an inverted U-shaped middle beam  52   m  mounted under the middle panel  44   m . An inverted U-shaped outer beam  52   o , typically mounted under the outer panel  44   o , is movably connected to the middle beam  52   m  typically via a synchronizing mechanism  54  such as two chains  56  or the like, connected to the inner and outer beams  52   i ,  52   o  at points  54   i  and  54   o  respectively, and respective sprockets  58  or the like mounted on longitudinal ends of the middle beam  52   m  to allow for simultaneous radial displacements of the outer beam  52   o  relative to the middle beam  52   m  and of the middle beam  52   m  relative to the inner beam  52   i  via the radial actuation of the hydraulic ram  46 . Typically, the outer beam  52   o  axially slides inside the middle beam  52   m  which axially slides inside the inner beam  52   i , in the radial direction of the work platform  20 . Accordingly, the outer panel  44   o  moves twice as fast as the corresponding middle panel  44   m  in relation to the corresponding inner panel  44   i.    
         [0038]    The controller  33  (schematically shown) of all the expansion actuating mechanisms  46  is conveniently located on the non-expandable portion  32  of the work platform  20  adjacent the main sleeve structure  18 . 
         [0039]    Although not shown herein, it would be obvious to one skilled in the art that a similar size-expandable platform  20  could be arranged in a rectilinear manner instead of a curved and arcuate manner to allow accommodation within a chimney structure of different cross-sectional shape, without deviating from the scope of the present invention. 
         [0040]    Although the present invention has been described with a certain degree of particularity, it is to be understood that the disclosure has been made by way of example only and is not limited to the features of the embodiments described and illustrated herein, but includes all variations and modifications within the scope and spirit of the invention as hereinafter claimed.