Patent Publication Number: US-6986405-B2

Title: Ladder with leg brace

Description:
BACKGROUND 
   The present disclosure relates to ladders. More particularly, the present disclosure relates to stabilization of ladders. 
   Ladders have a frame and one or more steps that people use for elevation when reaching for objects, painting walls, or any everyday task where extra elevation would be helpful. Some ladders can be folded for ease of storage when the ladder is not being used. 
   SUMMARY 
   According to the present disclosure, a ladder is provided. A foldable frame of the ladder includes first and second leg units which can be moved relative to one another between folded and unfolded positions. A leg brace is coupled to the leg units to bias the leg units toward one another to stiffen the frame in response to spreading of the leg units away from one another to the unfolded position by a leg spreader. 
   The leg brace is, for example, X-shaped and includes a pair of cables and a cable connector. One of the cables is coupled to a pair of legs of the first leg unit. The other cable is coupled to a pair of legs of the second leg unit. The cable connector is coupled to a middle portion of each cable and is configured, for example, as a small sleeve surrounding and deformed to grip the cable middle portions. 
   The cable brace is useful with a variety of leg spreaders. For example, in one embodiment, the leg spreader includes an overcenter linkage that locks the leg units in the unfolded position. In other another embodiment, the leg spreader includes a step coupled to one of the leg units for pivotable movement and a link coupled to the step and the other leg unit for relative movement of the leg units upon pivotable movement of the step. 
   Additional features of the apparatus will become apparent to those skilled in the art upon consideration of the following detailed description exemplifying the best mode of the disclosure as presently perceived. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The detailed description particularly refers to the accompanying figures in which: 
       FIG. 1  is a perspective view showing a ladder including a foldable frame and an X-shaped leg brace that is coupled to legs of front and rear leg units of the frame and that is tensioned to bias the leg units toward one another to stiffen the frame in response to spreading of the leg units away from one another to an unfolded position by a leg spreader in the form of, for example, an overcenter linkage; 
       FIG. 2  is a sectional view taken along lines  2 — 2  of  FIG. 1  showing the X-shaped leg brace including a cable connector coupled to a first cable that is coupled to the legs of the front leg unit (on the right) and a second cable that is coupled to the legs of the rear leg unit (on the left); 
       FIG. 3  is a side elevation view showing the ladder in a folded position; 
       FIG. 4  is a side elevation view showing unfolding of the ladder; 
       FIG. 5  is a side elevation view showing the ladder in the unfolded position; 
       FIG. 6  is an enlarged top plan view, with portions broken away, showing the cable connector coupled to middle portions of the first and second cables of the X-shaped leg brace; 
       FIG. 7  is a sectional view taken along lines  7 — 7  of  FIG. 6 ; 
       FIG. 8  is an enlarged perspective view showing an end of one of the cables coupled to one of the legs; 
       FIG. 9  is a perspective view showing a ladder including the X-shaped leg brace used with another type of leg spreader; 
       FIG. 10  is a side elevation view showing the ladder of  FIG. 9  in a folded position; 
       FIG. 11  is a side elevation view showing folding of the ladder of  FIGS. 9 and 10 ; and 
       FIG. 12  is a side elevation view showing the ladder of  FIGS. 9–11  in an unfolded position. 
   

   DETAILED DESCRIPTION 
   A ladder  10  includes a foldable frame  12 , a leg spreader  18 , and a leg brace  20  as shown in  FIGS. 1 and 2 . Front and rear leg units  14 ,  16  of the frame  12  are arranged for movement between a folded position shown in  FIG. 3  and an unfolded position shown in  FIGS. 1 ,  2 , and  5 . Leg brace  20  is used to bias leg units  14 ,  16  toward one another to stiffen frame  12  in response to spreading of leg units  14 ,  16  away from one another to the unfolded position by leg spreader  18 . Stiffening frame  12  promotes overall stability of ladder  10 . 
   Each leg unit  14 ,  16  includes a pair of legs  24 . Front leg unit  14  includes a number of steps  25  extending between legs  24  of front leg unit  14 . A number of cross members  27  extend between legs  24  of rear leg unit  16 . A pivot joint  26  is coupled to leg units  14 ,  16  for relative pivotable movement of leg units  14 ,  16  between the folded and unfolded positions. 
   Leg spreader  18  is arranged to pivot leg units  14 ,  16  away from one another to the unfolded position, as suggested in  FIGS. 3–5 . Leg spreader  18  thus provides means for spreading leg units  14 ,  16  away from one another to the unfolded position. Leg spreader  18  includes a pair of overcenter linkages  19  on opposite sides of frame  12 . Linkages  19  are similar to one another in structure and function so that the description of one linkage  19  applies to the other linkage  19  as well. 
   Linkage  19  is coupled to a leg  24  of each leg unit  14 ,  16 , as shown in  FIG. 2 . Linkage  19  includes a pair of links  29  and a connecting bracket  38 . Each link  29  is pivoted to one of legs  24  and connecting bracket  38 . A downward force  33  shown in  FIG. 5  and applied to connecting bracket  38  is transmitted through links  29  to leg units  14 ,  16  to cause relative pivotable movement of leg units  14 ,  16  away from one another until bracket  38  engages links  29  in an “overcenter,” locking position so as to lock leg units  14 ,  16  in the unfolded position. 
   Spreading of leg units  14 ,  16  to the unfolded position tensions leg brace  20 . When leg brace  20  is tensioned, it exerts an inward force on leg units  14 ,  16  so as to bias them toward one another. Leg spreader  18  resists relative inward movement of leg units  14 ,  16  toward one another when linkages  19  are deployed to their overcenter, locking position. Such operation of leg brace  20  and leg spreader  18  stiffens frame to promote stability of ladder  10 . 
   An embodiment of leg brace  20  is shown throughout the drawings. The illustrated leg brace  20  is X-shaped and includes a flexible tether such as a first cable  22  and a second cable  23  coupled to each leg unit  14 ,  16 , as shown in  FIG. 2 . First cable  22  is coupled to legs  24  of front leg unit  14 . Second cable  23  is coupled to legs  24  of rear leg unit  14 . A cable connector  28  included in leg brace  20  is coupled to a middle portion  36  of first cable  22  and middle portion  37  of second cable  23 , as shown in  FIGS. 6 and 7 , to establish the X shape of leg brace  20 . 
   A first end portion  30  and a second end portion  31  of cable  22  is coupled to each leg  24  of front leg unit  14  and a first end portion  40  and a second end portion  41  of cable  23  is coupled to each leg  24  of rear leg unit  16 , as shown with respect to one of end portions  30  in  FIG. 8 . End portion  30  extends through an aperture  32  formed in leg  24 . A blocker  34  is coupled to end portion  30  to block withdrawal thereof from aperture  32  to prevent detachment of end portion from leg  24 . 
   Each cable  22 ,  23  is relatively flexible and strong and includes a plurality of strands  33  of material made of, for example, steel or other metal material, as shown in  FIG. 7 . The flexibility of cables  22 ,  23  allows folding of leg brace  20  upon folding of frame  12 , as suggested in  FIG. 3 , for ease of storage of ladder  10 . The strength of cables  22 ,  23  facilitates tensioning of cables  22 ,  23 . Each cable  22 ,  23  is arranged to be tensioned to bias legs  24  toward a central portion of leg brace  20  (defined by connector  28  and middle portions  36 ) to stiffen frame  12  to promote overall stability of ladder  10  upon pivotable movement of leg units  14 ,  16  to the unfolded position by leg spreader  18 . In other embodiments, the flexible tethers may be cords, chains, lines, ropes, or the like. 
   The illustrated cable connector  28  is configured as a sleeve, as shown in  FIG. 7 . Middle portion  36  of cable  22  and middle portion  37  of cable  23  extend through sleeve  28 . Sleeve  28  is crimped or otherwise deformed to grip middle portions  36 . 
   Leg brace  20  is useful with another ladder  110  shown  FIGS. 9–12 . Ladder  110  includes a frame  112  and a leg spreader  118 . Frame  112  includes front and rear leg units  114 ,  116  which are coupled to one another for pivotable movement between folded and unfolded positions, as suggested in  FIGS. 10–12 . One of cables  22  is coupled to legs  124  of front leg unit  114  and the other cable  23  is coupled to legs  124  of rear leg unit  116 . Cables  22 ,  23  are arranged to be tensioned to bias leg units  114 ,  116  toward one another to stiffen frame  112  in response to spreading of leg units  114 ,  116  away from one another to the unfolded position by leg spreader  118 . 
   Leg spreader  118  is arranged to pivot leg units  114 ,  116  away from one another to the unfolded position, as suggested in  FIGS. 10–12 . Leg spreader  18  thus provides means for spreading leg units  14 ,  16  away from one another to the unfolded position. 
   Leg spreader  118  includes a step  140  and at least one link  142 , as shown in  FIGS. 11 and 12 . Step  140  is pivoted to front leg unit  114 . Link  142  is pivoted to step  140  and to a cross member  144  mounted to legs  124  of rear leg unit  116 . Step  140  and link  142  cooperate to cause relative pivotable movement of leg units  114 ,  116  between the folded and unfolded positions upon pivotable movement of step  140 . When step  140  is pivoted to a horizontal, use position onto cross member  114 , as shown in  FIGS. 9 and 12 , leg units  114 ,  116  are spread away from one another to the unfolded position. In this way, cables  22 ,  23  are tensioned to bias leg units  114 ,  116  toward one another to stiffen frame  112  to promote stability of ladder  110 . A latch  146  is mounted to step  140  for engagement with cross member  144  to lock step  140  in its horizontal, use position and thereby lock frame  112  in its unfolded position. 
   Leg brace  20  is useful with a wide variety of ladders in addition to ladders  10  and  110 . Leg brace  20  is useful with the structure disclosed in U.S. Pat. No. 6,427,805, the disclosure of which is hereby incorporated by reference herein. 
   With respect to ladder  10 , leg brace  20  provides means for biasing leg units  14 ,  16  toward one another to stiffen frame  12  in response to spreading of leg units  14 ,  16  away from one another to the unfolded position by spreading means  18 . With respect to ladder  110 , leg brace provides means for biasing leg units  114 ,  116  toward one another to stiffen frame  112  in response to spreading of leg units  114 ,  116  away from one another to the unfolded position by spreading means  118 . 
   An optional X-shaped leg brace (not shown) for use with ladders  10 ,  110  or other ladders includes a pair of cables that crisscross one another and a cable connector coupled to middle portions of the cables. Each cable is coupled to a leg of one leg unit and to a diagonally opposite leg of the other leg unit.