Patent Publication Number: US-2006006024-A1

Title: Step ladder having a top step with magnetic properties

Description:
BACKGROUND OF THE INVENTION  
      The present invention relates generally to ladders and more particularly to step ladders.  
      Step ladders are a well know and widely used type of ladder. Step ladders usually include a pair of rear legs, a plurality of steps, including a top step, attached to the pair of rear legs at different levels, a pair of front legs attached to the top step and a plurality of cross pieces connecting the two front legs at different locations. These ladders may also include a fold out tray as well as brackets for interconnecting the front and rear legs at intermediate locations.  
      It is common practice for carpenters, painters and the like to use a step ladder to accomplish their work. Very often, the user will place his tools, accessories, or work materials on the top step of the ladder. The problem with this practice is that the tool, accessory or work materials will often fall or roll off of the top step, especially when the step ladder is moved from one location to another.  
      In U.S. Pat. No. 6,587,022 to R. M. Devine there is disclosed a foldable, portable, magnetic tool mat which may be mounted on the top step of a collapsible ladder. The tool mat includes generally rectangular obverse and reverse panels each formed of flexible material and connected together along substantially common side and end margins and along evenly spaced apart seam lines extending between said side margins defining elongated magnet bar holding portions. An elongated permanent magnet bar is held within each holding portion each without substantially inhibiting selective tool mat folding for fit and storage. The reverse panel is substantially thicker than the obverse panel for better wear characteristics and maximal magnet attractive forces for tool and hardware retention. An attaching strap holds the tool mat.  
      In U.S. Pat. No. 5,624,093 to R. W. Gemmell there is disclosed a paint tray assembly which includes a ladder clamp to secure the tray to a ladder or scaffold and magnetic holder and swing away rod providing mechanism for retaining paint brushes in the tray. A detachable handle attaches to the tray to permit relocation of the tray from one area to another minimizing the possibility of unwanted spillage of paint from the tray.  
      In U.S. Pat. No. 5,098,052 to D. L. Beck there is disclosed a tray member including at least one pair of opposite side margin depending flanges and a center downwardly recessed portion whose undersurface is co-planar with the lower edges of the depending flanges. The downwardly recessed center portion defines an upwardly opening recess in which to receive the lower end of a paint can and the tray member includes widely spaced apart depending threaded shanks from which a clamp bar is supported through the utilization of wing nuts threadedly engaged on the shanks. The tray member may be slid into position on the horizontal shelf of a step ladder and removably clamp engaged with the shelf by tightening the wing nuts in order to clamp the shelf between the clamp bar and the underside of the tray member. In addition, the upper surface of the downwardly recessed central portion of the tray member as well as the upper surfaces of the tray member disposed about the downwardly recessed central portion of the tray member are covered with magnetized panels, whereby ferris material items placed thereon will be magnetically held-in position on the tray member.  
      In U.S. Publication No. US002/0070137A1 to K. Hedger there is disclosed a tool and material holder fitting to the top of a step ladder which has selectable detachable panels having and presenting an extremely large number of variously selectable pockets, cavities, loops, clips, hanger, hooks and the like which securely hold a great variety of power and hand tools, caulking guns, paint brushed and paint pads. The holder is stiffened by internal tubes and sheet preferably made from strong shape-retentive plastic, and will stand upright upon the floor. A major loop maintained open by an insert with a shape memory holds a large paint pail, bucket or can, and is optionally re-sizable to hold one or two smaller cans. A shallow reservoir on a top panel overlying the top step of the step ladder has a magnetic bottom for conveniently holding small ferrous items. A detachable strap and shoulder harness permits great loaded weight to be conveniently and safely carried.  
      Other patents and patent applications of interest include U.S. Pat. No. 5,301,822 to E. S. Coleman et al; U.S. Pat. No. 5,500,631 to J. A. Negus; U.S. Pat. No. 6,341,666 to B. W. Allen; U.S. Pat. No. 6,614,337 to S. D. Winnad; U.S. Pat. No. 6,637,782 to C. D. McCoy et al; U.S. Pat. No. 6,698,699 to R. B. Bailey; and U.S. Patent Application Pub. No. 2004/0020716 to J. C. Carly.  
      Accordingly, it is an object of this invention to provide a step ladder having a top step which is adapted to prevent metallic tools or materials from sliding or rolling off of the top step.  
      It is another object of the invention to provide a step ladder having a top step wherein various ferrous material objects may be removably and stationarily supported thereon against accidental dislodgement therefrom.  
      Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, embodiments of this invention.  
     SUMMARY OF THE INVENTION  
      A step ladder constructed according to the teachings of this invention comprises a pair of rear legs, a pair of front legs, a plurality of steps attached to said rear legs and a plurality of cross-pieces attached to the front legs. The plurality of steps includes a top step, which is also attached to said pair of front legs, some intermediate steps and a bottom step. The top step includes a plate made of plastic, the plate having a top surface and a bottom surface. The top step also includes magnetic means for magnetically holding ferrous objects which may be placed on the top surface of the plastic plate. The magnetic means is permanently fixed to the plastic plate.  
      The magnetic means may either comprise one or more permanent bar magnets or a plurality of magnetic particles or one or more panels of magnetic sheeting. The magnetic means may either be imbedded into the plastic plate, attached to the bottom surface of the plastic plate or attached to the top surface of the plastic plate.  
      Various other features and advantages will appear from the description to follow. In the description, reference is made to the accompanying drawings which form a part thereof, and in which is shown by way of illustration, various embodiments for practicing the invention. The embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. The following detailed description is therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      In the drawings wherein like reference numerals represent like parts:  
       FIG. 1  is a fragmentary pictorial perspective view of one embodiment of a step ladder constructed according to this invention, one of the rear legs in the step ladder being broken away at the bottom for convenience;  
       FIG. 2  is an enlarged plan view taken from the top and partly broken away of the top step in the folding step ladder shown in  FIG. 1 ;  
       FIG. 3  is an enlarged sectional view taken substantially upon the plane indicated by section line  3 - 3  of  FIG. 2 ;  
       FIG. 4  is a perspective view partly broken away of a modification of the top step in the step ladder in  FIG. 1 ;  
       FIG. 5  is a perspective view of another modification of the top step in the step ladder in  FIG. 1 ;  
       FIG. 6  is a bottom view of the top step shown in  FIG. 5 ;  
       FIG. 7  is a front view partly broken away of the top step shown in  FIG. 6 ;  
       FIG. 8  is a perspective view of another modification of the top step shown in  FIG. 1 ;  
       FIG. 9  is a plan view taken from the top of the top step shown in  FIG. 8 ;  
       FIG. 10  is a section view taken along lines  10 - 10  in  FIG. 9 ;  
       FIG. 11  is a perspective view of another modification of the top step shown in  FIG. 1 ; and  
       FIG. 12  is a plan view taken from the bottom of the top step shown in  FIG. 11 ;  
       FIG. 13  is a section view taken along lines  13  in  FIG. 12 .  
       FIG. 14  is a perspective view of another modification of the top step in the step ladder in  FIG. 1 ;  
       FIG. 15  is a top view of the top step shown in  FIG. 5 ;  
       FIG. 16  is a section view taken along lines  16 - 16  of the top step shown in  FIG. 15 ;  
       FIG. 17  is a perspective view of another modification of the top step shown in  FIG. 1 ;  
       FIG. 18  is a plan view taken from the top of the top step shown in  FIG. 17 ;  
       FIG. 19  is a section view taken along lines  19 - 19  in  FIG. 18 .  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Referring now to the drawings, there is shown in  FIG. 1 a  step ladder  11  constructed according to this invention.  
      Step step ladder  11  includes a pair of rear legs  13  and  15  and a pair of front legs  17  and  19 . A plurality of steps are fixedly attached to rear legs  13  and  15 , at different levels, the plurality of steps including a bottom step  21 , a plurality of intermediate steps  23 ,  25 ,  27  and  29  and a top step  31 . Rear legs  13  and  15  are fixedly secured to top step  31  by fasteners  34 . A plurality of cross pieces  35 ,  37  and  39  are fixedly attached to front legs  17  and  19  at different levels. Front legs  17  and  19  are pivotally mounted onto top step  31  by pivot fasteners  41 , one on each side of top step  31 . Front legs  17 ,  19  and rear legs  13 ,  15  are interconnected by hinge brackets  43  and  45 .  
      As described thus far, ladder  11  is a conventional step ladder.  
      Referring now also to  FIG. 2  and  3 , top step  31  includes a generally rectangular plate  47  mad of a molded rigid plastic. Plate  47  has a top surface  49 , a bottom surface  51 , a front surface  53 , a back surface  55  and side surfaces  57  and  59 . A plurality of permanent unipolar bar magnets  61 ,  63 ,  65  and  67  of appropriate strength are imbedded in plate  47  between top surface  49  and bottom surface  51  for magnetically holding magnetically attractable objects such as metal screws or metal tools which may be placed on top surface  49  of plate  47 . The number, size and exact location of magnets  61 ,  63 ,  65  and  67  within plate  47  are for illustrative purposes only.  
      In  FIG. 4  is shown a modification of top step  31 , the modification of top step  31 , the modification being identified by reference numeral  69 . Instead of bar magnets as in top step  31 , top step  69  includes a generally rectangular plate  71  made of a molded rigid plastic which is similar in overall shape to top step  31  but which is imbedded with a plurality of magnetic particles  73  in the portion of top step  69  between its top surface and its bottom surface.  
      In  FIGS. 5-7  is shown another modification of top step  31 , the modification being identified by reference numeral  75 . Top step  75  includes a generally rectangular plate  77  of a molded rigid plastic. Plate  77  includes a top surface  79  and a bottom surface  81 . A plurality of permanent unipolar bar magnets  83 ,  85 ,  87  and  89  are fixedly secured by a suitable adhesive  91  to bottom surface  81  of top step  79 .  
      In  FIGS. 8-10  is shown another modification of top step  31 , the modification being identified by reference numeral  93 . Top step  93  includes a generally rectangular plate  95  of a molded rigid plastic. Plate  95  includes a top surface  97  and a bottom surface  99 . A plurality of permanent unipolar bar magnets  101 ,  103 ,  105  and  107  are fixedly secured by a suitable adhesive  109  to recesses  111 ,  113 ,  115  and  117  in top surface  97 , the recesses and bar magnets being sized such that the top surfaces for the bar magnets are flush with top surface  97 .  
      In  FIGS. 11-13  is shown another modification of top step  31 , the modification being identified by reference numeral  119 . Top step  119  includes a generally rectangular plate  121  of a molded rigid plastic. Plate  121  includes a top surface  123  and a bottom surface  125 . A panel of magnetized material  127  fixedly secured by a suitable adhesive  129  to bottom surface  125  of top step  119 .  
      In  FIGS. 14-15  is shown another modification of top step  31 , the modification being identified by reference numeral  131 . Top step  131  includes a generally rectangular plate  133  of a molded rigid plastic. Plate  133  includes a top surface  135  and a bottom surface  137 . A panel of magnetized material  138  is imbedded in plate  135  between top surface  135  and bottom surface  137 .  
      In  FIGS. 17-19  is shown another modification of top step  31 , the modification being identified by reference numeral  141 . Top step  141  includes a generally rectangular plate  143  of a molded rigid plastic. Plate  143  includes a top surface  145  and a bottom surface  147 . A panel of magnetized material  149  is fixedly secured by a suitable adhesive  151  to top surface  145  of top step  141 .  
      Examples of panels of magnetized material may be found in U.S. Pat. Nos. 5,098,052; 6,614,337 and 6,637,792, which patents are incorporated herein by reference.  
      The embodiments shown in the present invention are intended to be merely exemplary and those skilled in the art shall be able to make numerous variations and modifications to it without departing from the spirit of the present invention. All such variations and modifications are intended to be within the scope of the present invention as defined in the appended claims.