Abstract:
The rung-extension consists of frame having a pair of vertically extending supports and a number of vertically spaced treads which extend between the two supports. Hooks are provided for attaching the frame to a ladder such that the upper wall of each tread is at the same level a separate rung of the ladder.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to an extension for the rungs of a ladder and more particularly to an extension having treads for increasing the area of the upper surface of the rungs of the ladder. The term “rung” is intended to refer to the horizontal support of any ladder and to include not only what is commonly referred to as a “rung” but also a solid bar and a step of a stepladder.  
       BACKGROUND OF THE INVENTION  
       [0002]     The rungs of most conventional ladders provide a relatively small area of contact for the feet of persons who are using the ladders. By reason of the small area, the feet of persons who spend relatively long periods of time on ladders such as painters and electricians become very painful over time. Such persons usually experience little relief from pain if they wear boots having stiff soles. While such boots may help to reduce or even eliminate pain in their feet and ankles, they will provide little if any relief to the lower and upper parts of their legs as well as their backs and as a result, the legs of persons wearing such boots may become very painful over time.  
         [0003]     The rung-extension of the subject invention has a number of treads which enlarge the upper areas of the rungs of a ladder. The feet of a person using a ladder to which the rung-extension is attached contact not only the rungs but also the treads of the rung-extension. The rung-extension provides foot-support which is substantially greater than the rungs and act to reduce or eliminate the pain which is experienced in the feet and legs of a person on a ladder which lacks such an extension.  
         [0004]     Stepladders often provide inadequate support for the feet of persons on such ladders and the attachment of the subject invention is also useful for increasing the upper area of the steps of such ladders with resulting benefit to such persons.  
         [0005]     The rung-extension of the invention has means for adjusting the device to fit onto both non-extendible and extendible ladders.  
         [0006]     Briefly, the rung-extension of the subject invention comprises a frame provided with a tread having an upper wall for supporting a user&#39;s foot; and means for removably attaching the frame to the ladder such that the upper wall is in position to support the same said foot as is supported by a rung of the ladder. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0007]     The rung-extension of the invention is described with reference to the accompanying drawings in which:  
         [0008]      FIG. 1  is a perspective view of a first embodiment of the rung-extension in conjunction with a conventional extendible ladder made up of two ladder-components;  
         [0009]      FIG. 2  is a perspective view of a non-extendible ladder and the rung-extension separated from the ladder;  
         [0010]      FIG. 3  is a perspective view of a the rung-extension attached to a non-extendible ladder;  
         [0011]      FIG. 4  is a side elevation of the rung-extension attached to a non-extendible ladder;  
         [0012]      FIG. 5  is a side elevation of the rung-extension attached to an extendible ladder having two ladder components;  
         [0013]      FIG. 6  is an elevation of a second embodiment of the rung-extension;  
         [0014]      FIG. 7  is a front elevation of a third embodiment the rung-extension attached to a conventional non-extendible ladder having non-parallel side supports;  
         [0015]      FIG. 8  is an enlarged perspective view of the tread of the rung-extension of  FIG. 7 ;  
         [0016]      FIG. 9  is a perspective view, in smaller scale, of a the rung-extension of  FIG. 7  having a number of treads;  
         [0017]      FIG. 10  is a perspective view of a fourth embodiment of the rung-extension in conjunction with a conventional non-extendible ladder; and  
         [0018]      FIG. 11  is an elevation and partly in section on line  11 - 11  of  FIG. 10 . 
     
    
       [0019]     Like reference characters refer to like parts throughout the description of the drawings.  
       DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0020]     With reference of  FIG. 1 , the rung-extension of the invention, generally  10 , is shown in conjunction with a conventional extendible ladder, generally  12  having two ladder-components  12   a,b.  The two ladder-components slide relative to one another to lengthen or shorten the effective length of the ladder and each has a number of vertically spaced rungs, bars or steps  14  (referred to below simply as “rungs”) fixed between two horizontally spaced supports  16 ,  18 . As is conventional, the rungs are spaced approximately one foot apart.  
         [0021]     With reference to  FIG. 2 , the rung-extension has a pair of vertically extending stationary panels  20  and a pair of sliding panels  22  located outside the stationary panels. A number of vertically spaced treads  24  are fixed between the two stationary panels by means of bolts or rivets.  
         [0022]     The treads are spaced apart approximately the same distance as the rungs of the ladder. That spacing will be one foot except in very unusual circumstances.  
         [0023]     The treads can be connected to the stationary panels by means other than bolts or rivets. In  FIG. 3 , they are shown as being connected by hinges. In that case, one hinge is attached to the upper surface of each tread on the same side as hinge  25  while a second hinge is attached to the lower surface of each tread on the opposite side. The rung-extension can then be collapsed for storage when not in use by folding the two stationary panels together.  
         [0024]     The two panels  20 ,  22  are interconnected by bolts  26 , each of which extends through an aperture in the stationary panel and through a slot  28  in the sliding panel. Heads  30  and wing nuts  32  at opposite ends of the bolts secure the bolts to the panels. By means of grooves  28 , the elevation of the sliding panel can be adjusted relative to the stationary panel.  
         [0025]     With reference to  FIGS. 2 and 4 , each stationary panel has a number of horizontally extending grooves  34  which are spaced vertically along the length of the panel for receipt of the rungs  36  of the ladder  38 . A hook  40  extends downwardly into the mouth  34   a  of each groove for contacting the front face  36   a  of the rung and preventing the rung-extension from sliding backward and separating from the ladder when the rung-extension is in contact with the ladder.  
         [0026]     The sliding panel  22  has a front edge  42  which is spaced apart from each hook by a gap  44  of sufficient width to receive the rungs of the ladder when the extension is the position relative to the ladder illustrated in  FIG. 4 . In that position the front edge  42  of the sliding panel contacts the rear face  36   b  of each rung and prevents the rung-extension from sliding forward relative to the rung. Accordingly, the hook and the front edge of the sliding panel cooperate with one another to minimize relative movement between the rung-extension and the rungs of the ladder when the ladder is in position for use.  
         [0027]     With reference to  FIG. 5 , the ladder, generally  50  is extendible and has forward and rear ladder-components,  52 ,  54  each having a number of rungs,  52   a,    54   a,  respectively. As is conventional, the ladder is designed such that at each point at which the movement of one ladder-component is checked relative to the other, the rungs in each ladder-component are at approximately the same elevation as those of the other component.  
         [0028]     In  FIG. 4 , the gap  44  between the hook and forward edge of the sliding panel is only sufficient to accommodate one rung. In  FIG. 5 , two rungs are accommodated in the gap and the space must be enlarged to accommodate them. The space may be enlarged by adjusting the position of the sliding panel relative to the stationary pane. In order to do so, wing nuts  60  are loosened to allow the sliding panel  62  to move downward relative to the stationary panel  64 . It will be noted that the width  66  of the sliding panel, measured normally from its rear edge  68  to its forward edge  70  varies from a maximum in segment  70   a  of the edge to a minimum in segment  70   b.  As the panel moves downward, the segment of the forward edge which faces hook  72  changes from its maximum as illustrated in  FIG. 4 , to its minimum as illustrated in  FIG. 5 . When segment  70   b  faces hook  72 , there is sufficient space to accommodate two rungs however the space is such that only minimal movement of the two rungs in the space is possible.  
         [0029]     With reference to  FIG. 6 , a second embodiment of the rung-extension of the invention includes a pair of spaced panels  80 ,  82  between which treads  84  extend. A groove  88  is formed in each panel for removable receipt of any one of the rungs of a ladder. The grooves are horizontally spaced apart when the rung-extension is upright in position for use as illustrated in the drawing. A hook  86  extends downwardly into each groove and engages and prevents unintended removal of the rung from the groove.  
         [0030]     In  FIGS. 7 and 9 , the illustrated ladder, generally  90  has a pair of converging supports  92  to which a number of vertically spaced rungs  94  are affixed. The ladder is shown in conjunction with a third embodiment of the rung-extension of the invention, indicated generally  96 . The latter extension has a pair of stationary panels  98  but lacks the sliding panels of the rung-extension described previously.  
         [0031]     A number of vertically spaced treads  100  are attached to stationary panels  98 . The treads are shown in detail in  FIG. 8 . With reference to that Figure and to  FIG. 9 , the treads each have a central channel-shaped portion  102  which opens downwardly and defines a recess  104  for receipt of a plate  106  in each end. The plates slide in and out of the recesses in the direction of arrow  108 . A pair of parallel slots  110  is formed in the plates for receipt of bolts  112  which pass through openings in the central portion  102 . Wing nuts  114  are threadably attached to the bolts in order to tighten the plate to the central portion. The plate may accordingly be selectively prevented or allowed to slide relative to the central portion.  
         [0032]     The ends of the central portion extend into elongated openings  116  formed in each stationary panel and are accordingly supported by the panels. With reference to  FIG. 7 , the plates can be selectively extended to the converging supports  92  of the ladder in order to provide continuous treads for the user of the ladder to step on. It will be observed that the treads extend across the entire space between the two converging supports whether the treads are near the bottom of the ladder where the supports are relatively far apart or near the top where the supports are relatively close.  
         [0033]     With reference to  FIGS. 10 and 11 , the fourth embodiment of the rung-extension of the invention has a pair of spaced panels  120  between which treads  122  extends. A connector  124  is attached to each panel and each connector is in the shape of a channel having a web  126  and a pair of flanges  128  at opposite side edges of the web. Each connector extends around three walls of a separate support  130  of a conventional ladder, generally  132 .  
         [0034]     A collar  134  is fastened to each connector and each collar ends at an aperture formed in the web of the connector. The collars are both at the same elevation when the rung-extension is in position for use as illustrated in  FIG. 10 .  
         [0035]     A pin  136  is removably received in each collar. When the pin is inserted into the collar, it will pass through the opening in the web and through the hollow opening  138  of each rung of the ladder.  
         [0036]     The pin in each connector serves to attach the connector to the ladder with resulting attachment of the rung-extension to the ladder. When the pins are removed, the connectors of the rung-extension can be slid up and down the ladder in order to alter the position of the rung-extension on the ladder.  
         [0037]     It will be understood, of course, that modification can be made in the embodiments of the rung-extension of the subject invention without departing from the scope and purview of the invention as defined in the appended claims.