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BACKGROUND OF THE INVENTION 
   The present invention relates generally to a safety device for a ladder and, more particularly, to an attachment adapted to be conveniently secured to either or both sides of a ladder for supporting the ladder against slipping and falling. 
   Conventional ladder braces have stabilizing legs fastened to the ladder. The ladder braces are often large, unwieldy, difficult to install, complex to operate, and difficult to fold and retract when storing the ladder. The ladder braces are not effective for securing ladders from slipping or falling on uneven surfaces. 
   One attempt to provide a solution to the above problems is disclosed in U.S. Pat. No. 4,949,809 to Levi, et al. (“Levi”). A locking mechanism for longitudinally fixing a first and a second tubular pole appears to comprise a plurality of spaced, parallel teeth projecting radially outward from the first tubular pole for engagement with an adjacent notch on a locking ring mounted on the second tubular pole. By rotating the locking ring, teeth on the locking ring mesh with teeth on the first tubular pole to prevent longitudinal displacement between the two tubular poles. However, the meshed teeth can wear from frequent use, entailing unsafe conditions where the stabilizer no longer can lock because the teeth no longer mesh securely to prevent longitudinal movement of the tubular poles. The Levi patent does not seem to disclose a compact device to be set up for securing the ladder from lateral movement and to be stowed away when the ladder is not in use. The Levi patent also does not offer a simple mechanism for operating and adjusting the support to accommodate uneven surfaces. 
   U.S. Pat. No. 5,086,876 to Severson (“Severson”) discloses a foot-actuated ladder brace intended for stabilizing ladders. A foot-actuated extending, locking and folding means is provided for extending a foot link from its folded position to its extended position along the ladder base for interlocking the links together, for releasing the interlocked links, and for nesting and folding the links upwardly along a side rail of the ladder. The Severson patent does not seem to disclose a structure that would prevent twisting deflection of the side rails, which could lead to a person at the top of the ladder falling because the ladder, even with the brace, would not provide sufficient support. Additionally, the foot actuation does not seem to provide secure, easily recognizable locking of the ladder brace to prevent inadvertent collapse of the folding ladder brace while a person is at the top of the ladder. For example, a passerby could accidentally kick the foot-actuated ladder brace so that the brace folds up, leading to a hazardous situation for someone on the ladder. 
   As can be seen, there is a need for an improved apparatus and methods for stabilizing a ladder by securely locking the ladder stabilizer in place to prevent movement in lateral, torsional, and other directions to provide safety to persons using the ladder. There also is a need for an improved apparatus and methods for securing the ladder from inadvertent movement during use and for convenient stowage when the ladder is not in use. A simple mechanism for operating and adjusting the support to accommodate uneven surfaces is also needed. 
   SUMMARY OF THE INVENTION 
   In one aspect of the present invention, a ladder stabilizer comprises a main bracket; a lower arm connected to the main bracket; a foot bracket connected to the lower arm; an upper arm connected to the foot bracket; and a slide arm slidably inserted inside the upper arm. 
   In another aspect of the present invention, a ladder system comprises a ladder; a main bracket connected to a side rail of the ladder; a lower arm connected to the main bracket; a foot bracket connected to the lower arm; an upper arm connected to the foot bracket; and a slide arm telescopically slidable within the upper arm. 
   In a further aspect of the present invention, a ladder stabilizer comprises a main bracket; a lower arm connected to the main bracket; a foot bracket connected to the lower arm; an upper arm connected to the foot bracket; a slide arm; the upper arm and the slide arm each comprising a plurality of holes for telescopic adjustment; a first pin passing through one of the plurality of holes in the upper arm and passing through one of the plurality of holes of the slide arm; and a second pin passing through a bracket hole in the main bracket and passing through a slide arm box hole in the slide arm. 
   In a still further aspect of the present invention, a ladder stabilizer comprises a main bracket; a lower arm connected to the main bracket; a foot bracket connected to the lower arm; an upper arm connected to the foot bracket; and a slide arm; the upper arm and the slide arm each longitudinally extensible and contractible relative to each other. 
   In yet another aspect of the present invention, a ladder stabilizer comprises a main bracket; a lower arm connected to the main bracket; a foot bracket connected to the lower arm; an upper arm connected to the foot bracket; a slide arm slidably inserted into the upper arm; a first pin removably inserted through an upper arm hole in the upper arm and through a slide arm hole in the slide arm; and a second pin removably inserted into a bracket hole in the main bracket and through a slide arm box hole in the slide arm. 
   In a still further aspect of the present invention, a method for stabilizing a ladder comprises mounting a ladder stabilizer to a side rail of the ladder; wherein the ladder stabilizer includes; a main bracket connected to the side rail of the ladder; a lower arm connected to the main bracket; a foot bracket connected to the lower arm; an upper arm connected to the foot bracket; and a slide arm inserted into the upper arm. 
   These and other aspects, objects, features and advantages of the present invention, are specifically set forth in, or will become apparent from, the following detailed description of an exemplary embodiment of the invention when read in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front view of a ladder system, according to an embodiment of the present invention; 
       FIG. 2A  is a front view of ladder stabilizer, according to an embodiment of the present invention; 
       FIG. 2B  is a front view of ladder stabilizer, according to another embodiment of the present invention; 
       FIG. 2C  is a front view of a ladder stabilizer, according to yet another embodiment of the present invention; 
       FIG. 2D  is a front view of a ladder stabilizer, according to still another embodiment of the present invention; 
       FIG. 3  is a side view of a ladder system, according to yet another embodiment of the present invention; 
       FIG. 4  is a schematic of the main bracket of  FIGS. 2A and 2B ; 
       FIG. 5  is a side view of the main bracket of  FIG. 4 ; 
       FIG. 6  is an isometric view of the upper arm of  FIGS. 2A and 2B ; 
       FIG. 7  is an isometric view of the lower arm of  FIGS. 2A and 2B ; 
       FIG. 8  is an isometric view of the slide arm of  FIGS. 2A and 2B ; 
       FIG. 9  is a top view of the slide arm of  FIG. 8 ; 
       FIG. 10  is a rear view of the foot bracket of  FIGS. 2A and 2B ; 
       FIG. 11  is an interior view of the foot bracket of  FIG. 10 ; 
       FIG. 12  is a front view of the foot bracket of  FIG. 10 ; 
       FIG. 13  is an exterior view of the foot bracket of  FIG. 10 ; 
       FIG. 14  is an isometric view of the adjustment plate of  FIG. 2B ; and 
       FIG. 15  is a flow diagram of a method for stabilizing a ladder, according to an embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The following detailed description is of the best currently contemplated modes of carrying out the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims. 
   The present invention is useful for stabilizing and supporting ladders of various types to improve safety. When a person ascends the rungs of a ladder, the center of gravity rises with each step. To counteract the tendency for the ladder to fall, slip, flex near a bottom portion of a side rail, or otherwise fail to adequately support a person&#39;s weight, the present invention may serve to widely spread the weight at the ladder bottom to enhance safety. The present invention may be used wherever ladders can be used, such as for construction activities, building maintenance activities, repair activities or practically anywhere where activities must be performed at heights above ground level. 
   Conventional ladder stabilizers lack structure to support the side rails of a ladder. When a side rail of a ladder flexes, twists, or otherwise deflects, a ladder may fall, slip, or otherwise fail when a person or object is on the ladder. The present invention uses a main bracket, adjacent and parallel to a side rail of a ladder. The main bracket restrains the ladder side rail from flexing, twisting, or otherwise deflecting. The main bracket may also serve to guide the folding, storing, and movement of the components of the ladder stabilizer. 
   Conventional ladder stabilizers lack a foot bracket or a curved foot plate. The present invention may comprise a foot bracket for securing the ladder, even on uneven surfaces. The curved foot plate may serve to enhance stability on uneven or slippery surfaces. To adapt to various spaces and surfaces, a portion of the ladder stabilizer may be adjusted relative to other portions of the ladder stabilizer. 
   In more specifically describing the present invention, and as can be appreciated from  FIG. 1 , the present invention provides a ladder system  10  for safely supporting a ladder  12  when resting on a flat surface  30  or an uneven surface  32  by using a ladder stabilizer  14 . The ladder stabilizer  14  may comprise a main bracket  18 , which may be situated adjacent and parallel to a side rail  16  of the ladder  12 . The main bracket  18  may be connected to a lower arm  20  and a slide arm  26 . The slide arm  26  may be inserted, telescopically and slidably, into an upper arm  24 . A foot bracket  22  may be connected to the lower arm  20  and the upper arm  24 . A foot plate  28  may be connected to the foot bracket  22 . 
   As shown in  FIG. 2A , the ladder stabilizer  14  may be fastened to the ladder  12  along the side rail  16  by bolts  42 . A bracket hinge  38  may serve for rotating the lower arm  20  in relation to the main bracket  18 . One or more foot bracket bolts  50  may be used to connect the lower arm  20  to the foot bracket  22 . An arm hinge  40  may be used for rotating the upper arm  24  in relation to the foot bracket  22 . A first pin  34  may be inserted through one of a plurality of upper arm holes  44 , which may be aligned with one of a plurality of slide arm holes  46  for locking the slide arm  26  in place in relation to the upper arm  24 . Aligning at least one of the plurality of upper arm holes  44  with at least one of the plurality of slide arm holes  46  enables using the ladder stabilizer  14  on a variety of surfaces (for example, as shown in  FIG. 1 , a flat surface  30 , a sloping downward surface  92 , a sloping upward surface  90 , or an uneven surface  32 ). A second pin  36  may be inserted through a bracket hole  48  to lock the slide arm  26  in place in relation to the main bracket  18 . 
   Another embodiment of the present invention may be seen in  FIG. 2B . The ladder stabilizer  14 ′ may be the same as the ladder stabilizer in  FIG. 2A  but a partially covered ladder  12 ′ is used. The partially covered ladder may have a side rail boot  94  that covers at least a portion of the side rail  16  of the partially covered ladder  12 ′. The side rail boot  94  may be made out of a sturdy, resilient material, such as vinyl, nylon, rubber, high-strength polymers, and the like. The side rail boot  94  may be used to protect the side rail  16  from slipping along surfaces. The side rail boot  94  may also serve to protect a lower portion of the side rail  16  (such as the portion near where the ladder  12 ′ contacts a surface) from environmental damage, such as corrosion. When the side rail boot  94  is used, a top portion of main bracket  18  may not be vertically aligned evenly with a bottom portion of the main bracket  18 . To keep the top portion of the main bracket  18  aligned evenly with the bottom portion of the main bracket  18 , an adjustment plate  86  may be inserted between the side rail  16  and the top portion of the main bracket  18  to keep the main bracket  18  at an even distance from the side rail  16  when necessary. The adjustment plate may be made of any sturdy material, such as aluminum, steel, or high-strength plastic. With the adjustment plate  86 ′ in place, the ladder stabilizer  14 ′ may be securely attached to the ladder  12 ′ with the bolts  42 ′ that connect the main bracket  18 ′ to the tapered side rail  16 ′. 
   With reference to  FIG. 2C , there is shown an initial step in storing the ladder stabilizer  14  when not in use. The second pin  36  may be removed from the bracket hole  48  and the slide arm  26  to release the slide arm from the main bracket  18 . The first pin  34  may be removed from one of the plurality of upper arm holes  44  and one of the plurality of slide arm holes  46  (shown in  FIGS. 2A and 2B ) to allow the slide arm  26  to slide telescopically inside the upper arm  24 . The slide arm  26  may be inserted into the upper arm  24  until only a slide arm box  70  may be visible from the outside of the upper arm  24 . The upper arm  24  and the slide arm  26  may be rotated (along arm hinge  40 ) downward in relation to a surface  30 . The lower arm  20  may be rotated upward, in relation to the surface  30  along the bracket hinge  38 . 
   In  FIG. 2D , a next step in storing the ladder stabilizer  14  may be seen. The foot bracket  22 , along with the upper arm  24 , the slide arm  26 , and the lower arm  20  may be rotated away from the surface  30  and toward the main bracket  18 . The first pin  34  may be inserted through one of the plurality of upper arm holes  44  and one of the plurality of slide arm holes  46  (shown in  FIGS. 2A and 2B ). The second pin  36  may be inserted through the bracket hole  48  and an upper arm pin hole  52  (shown in  FIG. 2C ). In this manner, the ladder stabilizer  14  may be compactly stored when not in use. 
     FIG. 3  shows a side view of a ladder system  10 . The foot plate  28  may be curved in an upward direction to accommodate uneven surfaces, such as a sloping upward surface  90 . 
     FIG. 4  shows a front view of the main bracket  18 . The main bracket  18  may be comprised of any sturdy material, such as aluminum or steel. The bracket hole  48  may be used for inserting the second pin  36  for securing the slide arm  26  when using the ladder stabilizer  14  (as shown in  FIGS. 2A and 2B ) or for securing the upper arm  24  with the slide arm  26  when stowing the ladder stabilizer  14  (as shown in  FIG. 2D ). A bracket hinge hole  56  may be used for forming the bracket hinge  38  (shown in  FIG. 2D ). 
     FIG. 5  shows a side view of the main bracket  18  with bracket holes  58  for connecting the main bracket  18  to the side rail  16  of the ladder  12  (shown in  FIG. 2C ). 
     FIG. 6  shows the upper arm  24  of  FIGS. 2A and 2B . The upper arm  24  may be made of any sturdy material, such as aluminum or steel. A plurality of upper arm holes  44  may be used for inserting the first pin  34  to secure the upper arm  24  with the slide arm  26  of the ladder stabilizer  14  (shown in  FIGS. 2C and 2D ). The upper arm pin hole  52  may be used for inserting the second pin  36  when storing the ladder stabilizer  14  (as shown in  FIG. 2C ). An arm hinge hole  60  may be used for forming the arm hinge  40  (shown in  FIGS. 2A ,  2 B, and  2 C). 
     FIG. 7  shows the lower arm  20  of  FIGS. 2A and 2B . The lower arm  20  may be made of any sturdy material, such as aluminum or steel. One or more bracket holes  62  may be used for securing the foot bracket bolts  50  (shown in  FIGS. 2A ,  2 B, and  2 C). 
   The slide arm  26  of  FIGS. 2A and 2B  is shown in  FIG. 8 . The slide arm  26  may be made of any sturdy material, such as aluminum or steel. A plurality of slide arm holes  46  may be used for aligning with upper arm holes  44  (shown in  FIGS. 2A and 2B ). Insertion of the first pin  34  through the aligned upper arm holes  44  (shown in  FIGS. 2A and 2B ) and through the slide arm holes  46  may secure the upper arm  24  to the slide arm  26  when setting up the ladder stabilizer  14  (shown in  FIGS. 2A and 2B ). A slide arm box hole  54  may be aligned with the bracket hole  48  (shown in  FIGS. 2A and 2B ) when setting up the ladder stabilizer  14  (shown in  FIGS. 2A and 2B ) for insertion of the second pin  34 .  FIG. 9  shows a top view of the slide arm  26  of  FIG. 8 . A slide arm shank  68  may be located within the slide arm box  70  such that the slide arm  26  is hollow with an inner surface  74 . The slide arm box  70  may be welded to the slide arm shank  68 , for example, along an interface  72  between the slide arm shank  68  and the slide arm box  70 . 
     FIG. 10  shows a rear view of the foot bracket  22  of  FIGS. 2A and 2B . The foot bracket  22  may be made of any sturdy material, such as aluminum or steel. The foot plate  28 , connected to the foot bracket  22 , may be comprised of rubber or another polymer. The foot plate  28  may be secured to the foot bracket  22  by a rivet  82 , a screw, a bolt, or other fasteners. One or more foot bracket holes  84  may be used for inserting the foot bracket bolts  50  (shown in  FIGS. 2A and 2B ) to secure the foot bracket  22  to the lower arm  20  (shown in  FIGS. 2A and 2B ). An arm hinge hole  78  may be used for forming the arm hinge  40  (shown in  FIGS. 2A and 2B ) to secure the foot bracket  22  to the upper arm  24  (shown in  FIGS. 2A and 2B ). 
     FIG. 11  shows an interior view of the foot bracket  22  of  FIG. 10 . As can be seen, the foot bracket  22  may be nearly hollow. The foot plate  28  may be curved in an upward direction (as shown in  FIG. 11 ) to accommodate uneven surfaces. More than one rivet  82  may be used to secure the foot plate  28  to the foot bracket  22 . 
     FIG. 12  is a front view of the foot bracket  22  of  FIG. 10 . 
     FIG. 13  is an exterior view of the foot bracket  22  of  FIG. 10 . 
     FIG. 14  is an isometric view of the adjustment plate  86 . Plate holes  88  may be used for insertion of at least one bolt  42  when the adjustment plate  86  is used to align the main bracket  18  and the side rail  16  (as shown in  FIG. 2B ). 
     FIG. 15  shows a flow diagram of a method  200  for stabilizing a ladder. A step  210  may comprise mounting a ladder stabilizer to a side rail of the ladder wherein the ladder stabilizer includes a main bracket connected to the side rail of the ladder; a lower arm connected to the main bracket; a foot bracket connected to the lower arm; an upper arm connected to the foot bracket; and a slide arm inserted into the upper arm. Next, a step  220  may comprise placing the foot bracket onto a surface. Next, a step  230  may comprise connecting the slide arm to the main bracket. The method  200  may include a step  240  of inserting a first pin through the upper arm and through the slide arm. Likewise, a step  250  may include inserting a second pin through the main bracket and through a slide arm box on the slide arm. A further step  260  may comprise connecting a foot plate to the foot bracket. For tapered ladders, a step  270  may comprise inserting an adjustment plate between the main bracket and a side rail of a ladder. A step  280  may comprise connecting the slide arm to the main bracket and a step  290  may comprise securing the lower arm to the foot bracket with a foot bracket bolt. 
   It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.

Summary:
The present invention provides a method and apparatus for stabilizing a ladder for minimizing accidents. For example, a main bracket may be connected to a lower arm, a foot bracket may be connected to the lower arm, an upper arm may be connected to the foot bracket and a slide arm may be telescopically slidable inserted inside the upper arm. Pins may be inserted into holes within the main bracket, upper arm, lower arm, and slide arm to secure the ladder stabilizer. The main bracket may be attached to most ladders regardless of side rail thickness. The ladder stabilizer may accommodate varying surfaces, flat and uneven, with the ability to fold up against the vertical sides of the ladder in a small compact unit when not in use.