Patent Abstract:
An attachment for a straight ladder that can stabilize the ladder when placed against vertical surfaces that include a flat wall, an inside corner and an outside corner. Adjustments permit use around a window or other such structure within the wall. A tubular framework accepts two support arms. The support arms may be arranged in several different orientations within the framework. Pivotable sleeves attached to the underside of the framework accept the support arms to stabilize the ladder when placed against a tree or column. A tension spring between the sleeves assist the support arms holding the ladder against the tree. A plate affixed to the top of the framework supports a tray with depressions and cutouts so that tools and supplies may be kept close at hand.

Full Description:
This application claims the benefit of provisional application No. 60/374,773 filed Apr. 24, 2002. 
    
    
     FIELD OF THE INVENTION 
     The instant invention relates to a device for attachment to the top rungs of a ladder to stabilize the ladder against a vertical surface and maintain tools and supplies within easy reach of the user. 
     BACKGROUND OF THE INVENTION 
     Ladders placed against a wall have always posed a stability problem. The problem is more serious when the ladder must be used on a corner or near a window where there is often insufficient surface on which to support the rails. A variety of devices have been developed that have attempted to solve this problem. 
     In U.S. Pat. No. 2,327,317 Randall teaches a hollow frame to be attached by means of brackets to the rails of a ladder. An independent arm extends outward from each side of the hollow frame as needed. Angled portions attached to the arms make contact with the wall. A second embodiment provides straight portions extending forward from the arms at right angles. Each of the straight portions can be extended as far as needed and independent of the other so that the ladder can be stabilized against an irregular wall. This same arrangement can be used at the bottom of the ladder to stabilize it on irregular ground. The ends of the contacting parts may be pointed or have rubber feet to prevent slippage. Similar devices are taught by Werner (U.S. Pat. No. 3,568,801), Wing (U.S. Pat. No. 4,502,566) and Southern (U.S. Pat. No. 5,113,973). None of these devices can be used at corners of intersecting walls. 
     In U.S. Pat. No. 6,152,262, Jung discloses stabilizing bars that are stored within one hollow rung of a ladder. The bars can extend from the ladder at an angle and are composed of telescoping segments that can be locked in place to extend as far as needed. Additional supporting members can also be stored within another rung of the ladder. This invention cannot be adapted to surfaces that are not flat. 
     Burk teaches a U-shaped brace that is attached at the top of a ladder. The arms of the U extend forward and make contact with the wall. Rubber grips at the ends of the arms prevent slipping. A cross bar adds strength and a chain extending from the cross bar to another rung provides additional support. Sockets mounted on the inside of each arm at a 45° angle can accept additional extension arms by threading into the sockets. These extensions enable the brace to stabilize the ladder on an outside corner by gripping the wall on each side of the outside corner. (U.S. Pat. No. 2,592,006) Another U-shaped brace for use on a ladder provides additions for insertion at the end of each forward extending arm. The additions have ends that are turned inward at a 45° angle and covered with rubber sleeves for the support of the ladder on an outside corner. (Peters, U.S. Pat. No. 3,072,218) Neither of these devices are horizontally adjustable and therefore are of limited use around windows or other structures within the wall. 
     Brewer et al. in U.S. Pat. No. 4,593,790, disclose a foldable device to be attached to a ladder for stability. The device can be folded into several orientations so the ladder can be stabilized at an outside corner, an inside corner, an overhang and can be set to span a window. Spring loaded hinges enable the various configurations. This device is quite complex and appears cumbersome and heavy. 
     In U.S. Pat. No. 3,693,756, Walker et al. teach a U-shaped brace that can be attached to the top of a ladder with arms extending forward for stability against a wall and to the bottom of a ladder with arms extending downward for stability on the ground. A compartment for holding supplies can be attached to the brace as can hooks for such things as paint cans. The brace is of fixed dimensions and so is of limited use. Terwilliger (U.S. Pat. No. 3,146,854) discloses a ladder positioning attachment that consists of an upper plate and a lower plate with a centralized separator in between. The plates extend forward of and beyond the sides of the ladder. The portion of the attachment that lies between the rails is bolted to a rung. On each side of the device a leg is pivotally attached between the plates. There are several holes through the upper plate and another hole in each leg. The legs can be moved into several positions and set in place by inserting a fastener through the selected hole in the plate and the hole in the leg. As the angle of the legs change, so does the distance of the upper part of the ladder from the wall. Tools or other objects can be set on the flat upper plate. This device is only usable against a flat wall. 
     None of the prior art devices provide stability for a ladder at all wall variations and also provide means to hold tools and supplies. None of the prior art provides a means to keep small objects such as nails and screws close at hand and easy to reach. And none of the prior art patents teach the technology that will enable a ladder to be stabilized against a column or tree. There is a need for a device that can be attached to the top of any ladder and accomplish all of these tasks. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a stabilizing means for attachment to a ladder to enable the ladder to be set securely against a variety of vertical surfaces and also provides means to hold numerous tools and supplies within easy reach. 
     It is an object of the present invention to provide a stabilizer that can be easily and securely attached to any straight ladder. 
     It is another object of the present invention to provide a stabilizer for ladders that prevents the ladder from slipping once set in place whether against a flat wall or corner. 
     A further object of the present invention is to provide a stabilizer for ladders that can be used against most vertical surfaces and can span various structural variations such as windows and corners. 
     A still further object of the present invention is to provide a stabilizer for ladders that can hold a ladder securely against a tree or column. 
     Another object of the present invention is to provide a stabilizer that can also hold tools and supplies, including small objects such as screws and nails, so they are within easy reach. 
     A further object of the present invention is to provide a stabilizer that can quickly and easily be adapted from one type of vertical surface to another. 
     A still further object of the present invention is to provide a stabilizer that is inexpensive to manufacture and can be manufactured using readily available materials. 
     Another object of the present invention is to provide a stabilizer that can be quickly fastened securely to the ladder and can easily be removed therefrom 
     A still further object of the present invention is to provide a stabilizer with parts that fit within the framework for compact storage and easy transport. 
     The instant invention is a stabilizer for supporting a ladder of a type having parallel side rails and a series of transverse rungs set at regular intervals therebetween against a substantially vertical surface. The stabilizer comprises a tubular frame comprising a first rearward frame member fixedly attached longitudinally to a second forward frame member, and two angled frame members affixed near the center of the forward frame member at opposing acute angles thereto and lying in the same plane with the first and second frame members. There are two sleeves pivotally attached to the underside of the frame with a tension spring connecting the two sleeves. Two support arms, a rearward support arm and a forward support arm, are dimensioned to fit slidably and reversibly within the first frame member, the second frame member, the angled frame members and the sleeves. Each support arm is bent to form a leg extending at a right angle therefrom. Attachment means are affixed to the tubular frame for reversibly attaching the stabilizer to the ladder. 
    
    
     Other features and advantages of the invention will be seen from the following description and drawings. 
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a perspective view of a ladder with the stabilizer of the instant invention attached to the two top rungs; 
     FIG. 2 is bottom plan view of the stabilizer attached to a ladder and supported against a flat wall; 
     FIG. 3 is a side sectional view of the stabilizer through line  3 — 3  of FIG. 2; 
     FIG. 4 is a close up side plan view of the end of a support arm and the slip resistant contact foot; 
     FIG. 5 is a bottom plan view of the stabilizer with the support arms in opposing extensions to the view shown in FIG. 2; 
     FIG. 6 is a bottom plan view of the stabilizer with the arms in position for support against an outside corner; 
     FIG. 7 is bottom plan view of the stabilizer with the arms in position for support against a tree trunk; 
     FIG. 8 is bottom plan view of the stabilizer with the arms in position for support against an inside corner; 
     FIG. 9 is an exploded view of the stabilizer. 
     FIG. 10 is rear plan view of the first ladder fastener; 
     FIG. 11 is a side perspective view of the first ladder fastener; 
     FIG. 12 is a front perspective view of the first ladder fastener; 
     FIG. 13 is a rear plan view of the second form of the ladder fastener; 
     FIG. 14 is a sectional view through line  14 — 14  of the ladder fastener of FIG. 13; 
     FIG. 15 is a front perspective view of the ladder fastener of FIG. 13; 
     FIG. 16 is an exploded view of the connecting pin and opening in the plate; and 
     FIG. 17 is a side plan view of the connecting pin of FIG. 16 rotated 90°. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The ladder stabilizer  20  of the instant invention may be seen in use in FIGS. 1 and 3. There may be a frame  25  composed of rigid tubular material that may be square or rectangular in cross section and may form the body and main support of the stabilizer  20 . The frame  25  may be composed of four lengths of the tubular material. There may be a rearward frame member  26  and forward frame member  27 , of equal length, which may be joined together longitudinally and extend a substantial distance beyond the rails  22  on each side of the ladder  21 . Two additional short frame members  29  may be affixed to the forward frame member  27  at 45° angles to form a broad V shape. The short frame members  29  may not be centered on the forward frame member  27 . All of the frame members may lie in the same plane. The rearward frame member  26  and the forward frame member  27  may have a series of communicating apertures  28  through their upper and lower surfaces. The apertures  28  may be disposed beginning at one end and continuing to a point beyond the center in the rearward frame member  26  and beginning at the opposing end and continuing to a point beyond the center in the forward frame member  27 . 
     There may be two support arms, a rearward support arm  30  and a forward support arm  31  which may be composed of rigid tubular material that is dimensioned to fit easily within the frame members. The rearward support arm  30  may be slidably and reversibly disposed within the rearward frame member  26  and the forward support arm  31  may be slidably and reversibly disposed within the forward frame member  27 . Each of the support arms may be bent at a right angle near one end to form a forward extending leg  32 . The length of the leg for each support member may be different to compensate for the different positions of the frame members  26  and  27  and so that the stabilizer is parallel to a wall when properly positioned. (FIGS.  2  and  5 ). Therefore, the leg of the rearward support arm  30  may be longer than the leg of the forward support arm  31 . The off center placement of the short frame members  29  may also accommodate the different lengths of the legs  32 . 
     There may be a spherical foot  33  at the end of each leg. Each foot  33  may be covered with a skid resistant material or may be composed of a skid resistant material to prevent slippage of the stabilizer  20  and in turn the ladder  21  once they are properly positioned. Each foot  33  may have a collar  35  with a protruding button. The foot  33 , collar  35  and button may be composed of the same material and may be of unified construction The material may also be non-marking. The collar  35  may be dimensioned to fit within the end  37  of the leg  32  which may also be curved to receive the spherical foot  33 . There may be an opening  36  near the end  37  of the leg to receive the button and retain the foot  33  securely in place. These structures may be seen in FIG.  4 . There may be an aperture  34  through the opposing end of each support arm  30  and  31 . The support arms  30  and  31  may be inserted into their respective frame members  26  and  27  as far as desired until the apertures  34  in the ends of the support arms  30  and  31  communicate with the apertures  28  in the frame members  26  and  27 . A connecting pin  38  may be inserted through the apertures  28  and  34  to hold each of the support arms  30  and  31  securely place. Adjustments in width of the support base may easily be made by removing a connecting pin  38 , sliding a support arm to a new position and reinserting the connecting pin  38 . 
     There may be two sleeves  39  each attached at one of its ends to the center of the underside of the rearward frame member  26  by pivot pins  41 . A tension spring  40  may connect the two sleeves  39  near the opposing ends. The sleeves  39  may be dimensioned to reversibly contain the support arms  30  and  31 . See FIG.  7 . 
     A substantially rectangular top plate  42  may be affixed to the upper surface of the frame  25  such that the rear edge of the plate  42  may be aligned with the rear edge of the rearward frame member  26  and the plate  42  may be longitudinally centered on the frame  25 . There may be a concavity  43  centered on the forward edge of the plate  42 . Two lines of openings  44  may be disposed along the rear of the plate  42  positioned to communicate with the apertures  28  in the frame members  26  and  27  and dimensioned to receive the connecting pins  38  used to secure the support arms  30  and  31  in place. There may be small cutouts  45  in the surface of the plate  42  where tools such as hammers and pliers may be placed for easy access. Larger cutouts  46  may be used to receive containers for small objects such as screws and nails. These may be seen in FIG.  9 . The cutouts  45  and  46  may be positioned such that they do not lie above any of the frame members. 
     A removable tray  47  may be placed on top of the plate  42  and maybe substantially the same shape as the plate  42  with the same concavity  43  in the front edge. There may be a raised edge  48  about the entire circumference of the tray  47  as well as a full apron  49  which conceals the frame when the stabilizer  20  is viewed from the top or side. There may be two rows of openings  50  along the rear edge of the tray  47  communicating with the openings  44  in the plate  42  and the apertures  28  in the frame  25 . Small cutouts  51  in the tray  47  may communicate with the small cutouts  45  in the plate  42  for placement of tools, and depressions  52  in the surface of the tray  47  may fit into the large cutouts  46  in the plate  42  and may serve as receptacles for small articles such as screws or nails. The raised edge  48  may prevent any objects placed on the tray from rolling off. The connecting pins  38  used to maintain the support arms  30  and  31  in place may be attached to the tray  47  by chains  53  or other type of flexible connectors that may be long enough so the connecting pins  38  may reach all of the openings  44  and may guarantee that the connecting pins  38  cannot be misplaced. 
     The connecting pins  38  may have rings  72  attached to their top ends to which the chains  53  or other such flexible connectors may be attached and there may also be threads  73  at their bottom ends. The tray  47 , plate  42 , rearward frame member  26  and forward frame member  27  may all have communicating openings to receive the connecting pins  38 , as noted above. However, there may be specially shaped openings  74  in the bottom walls  75  of the rearward frame member  26  and forward frame member  27 . These shaped openings  74  may be sized and dimensioned to receive the threaded ends  73  of the connecting pins  38  so that when a connecting pin  38  is given a turn, it may become locked in place. This may also insure that once a connecting pin  38  is placed into the openings through the tray  47 , the plate  42  and the rearward frame member  26  or the forward frame member  27 , and the support arms  30  and  31  and locked into the openings  74  in the bottom walls  75  of the frames, the support arms  30  and  31  cannot become dislodged. The ring  72  at the top of each connecting pin  38  may be used to attach the chains  53  to the connecting pins  38  and may also act as a handle to assist in locking the connecting pins  38  securely in the shaped openings  74 . These features may be seen in FIGS. 16 and 17. 
     The stabilizer  20  may be attached to the ladder  21  by a first ladder fastener  54  which may be composed of two inverted U-shaped clips, an upper clip  55  and a lower clip  56 , which are spaced apart to fit over any two consecutive rungs  23  of the ladder  21 . The upper clip  55  may be substantially the width of the rungs  23  while the lower clip  56  may be considerably narrower. The clips  55  and  56  may be connected to each other by two struts  57  which are angled to form a “V”. The fastener  54  may be attached to the stabilizer frame  25  by permanently affixing the forward surface of the upper clip  55  to the center of the rear face of the rearward frame member  26 . The clips  55  and  56  may each have one vertical side  58 , the front of the clip, and one stepped side  59 , the rear of the clip, and a flat top portion  60 . The stepped side  59  may protrude outward in graduated steps so that the first ladder fastener  54  may be securely seated over rungs of different shapes and diameters, thus permitting the stabilizer to be used with many different ladders. 
     A spring loaded catch  61  may be pivotally attached to the center near the bottom edge of the stepped side  59  of the upper fastening clip  55 . There may also be an opening  62  above the catch  61  to provide room for the catch  61  to pivot upward and make contact with the rung  23  of the ladder  21 . The first ladder fastener  54  may be attached to any two consecutive rungs of the ladder  21 . See FIGS. 10,  11  and  12 . 
     There may be a second ladder fastener  66  that may be used for all straight ladders regardless of the spacing between the rungs. The second ladder fastener  66  may be used with ladders built to metric standards as well as U.S. standards. There may be two U-shaped clips, an upper clip  67  and a lower clip  68  having the same configurations and relative sizes as in the first ladder fastener  54  described above and which may also be used with rungs of varying shapes and diameters. However, in the second ladder fastener  66  the upper clip  67  may be inverted and the lower clip  68  may not be inverted such that the openings  69  in the two clips are facing each other. The forward surface of the upper clip  67  may be permanently attached to the stabilizer frame  25  at the center of the rear face of the rearward frame member  26  in the same manner as the first ladder fastener  54 . The upper clip  67  and lower clip  68  may be connected to each other by two struts  70  that may be parallel to each other. Each strut  70  may be composed of two tubular sections that slidably fit one within the other. There may be a tension spring  71  within the two sections that may enable the second ladder fastener  66  to be tightly seated around any two consecutive rungs of the ladder. See FIGS. 13,  14 , and  15 . In use the two clips  67  and  68  may be manually pulled apart expanding the struts  70  so that the clips  67  and  68  may be seated about the two consecutive rungs. Thereafter, the tension on the clips  67  and  68  may be released so that the struts  70  contract and hold the rungs securely. 
     The stabilizer  20  of the instant invention may be easily adapted to stabilize a ladder against a variety of vertical surfaces. When used against a flat wall  24  the support arms  30  and  31  may be inserted into the rearward frame member  26  and forward frame member  27  respectively as far as necessary and retained in place using the connecting pins  38 . The stabilizer  20  may be adjusted for use near or around a window or other structure within a flat wall  24  by extending the support arms  30  and  31  outwardly or inserting the support arms  30  and  31  further into the frame members  26  and  27 . FIG. 2 may show the stabilizer  20  against a flat wall  24  with the forward support arm  31  in an extended orientation and the rearward support arm  30  in its fully inserted orientation while FIG. 5 may show the support arms  30  and  31  in the opposite orientations. Such selections may be determined by the surface on which the ladder  21  is placed or structures on or within the wall  24 . 
     When a ladder  21  must be supported against a corner the support arms  30  and  31  may be removed from the rearward frame member  26  and forward frame member  27  by removing the connecting pins  38  and sliding the support arms  30  and  31  outward. The support arms  30  and  31  may then be positioned within the short frame members  29 . When the ladder is to be set against an outside corner  63  the support arms  30  and  31  may be positioned within the short frame members  29  so that the legs  32  may be turned inward and the feet  33  rest against the walls as shown in FIG.  6 . When the ladder is to be set against an inside corner  64  the support arms  30  and  31  may be positioned within the short frame members  29  so the legs  32  may be turned inward and the sides of the legs  32  may rest against the walls as seen in FIG.  8 . 
     A unique feature of the stabilizer  20  enables a ladder  21  to be stabilized when it must be supported against a tree, structural column, or utility pole. For this use the support arms may be positioned within the two sleeves  39  with the legs  32  turned outward. The stabilizer  20  may rest directly against a tree  65  which may fit within the concavities  43  in the front edges of the plate  42  and in the tray  47 . The support arms  30  and  31  may grip the tree  65  because of the pivotability of the sleeves  39  and the tension exerted by the tension spring  40  connecting them. This may be seen in FIG.  7 . 
     The various parts of the instant invention may be made of aluminum which may provide strength while minimizing weight. Other strong rigid materials may also be used. Square tubing is preferable for the frame, sleeves and support arms, though tubing that is rectangular in cross section or otherwise shaped may be acceptable. The tray may be made of a moldable plastic or other polymeric material for ease of manufacture. The feet may be made of a form of rubber or other polymeric material that is non-marking. 
     The tray of the preferred embodiment may be 90 cm wide and 16 cm deep. The support arms may be 50 cm long and the leg of the rearward support arm may extend forward 30 cm and the leg of the forward support arm may extend forward 23 cm. Depending on the position of the support arms, the support base of the stabilizer may extend from 90 cm to 150 cm and so may be able to span obstacles of considerable width. 
     While one embodiment of the present invention has been illustrated and described in detail, it is to be understood that this invention is not limited thereto and may be otherwise practiced within the scope of the following claims. 
     HAIG PARTS LIST 
       20  LADDER STABILIZER 
       21  LADDER 
       22  SIDE RAIL OF LADDER 
       23  RUNG OF LADDER 
       24  WALL 
       25  FRAME 
       26  REARWARD FRAME MEMBER 
       27  FORWARD FRAME MEMBER 
       28  APERTURES IN FRAME 
       29  SHORT FRAME MEMBERS 
       30  REARWARD SUPPORT ARM 
       31  FORWARD SUPPORT ARM 
       32  LEG 
       33  FOOT 
       34  APERTURE IN SUPPORT ARM 
       35  COLLAR 
       36  CUTOUT 
       37  CURVED END OF FOOT 
       38  CONNECTING PIN 
       39  SLEEVE 
       40  TENSION SPRING 
       41  PIVOT PINS 
       42  PLATE 
       43  CONCAVITY IN PLATE EDGE 
       44  OPENINGS IN PLATE FOR PINS 
       45  SMALL CUT OUT FOR TOOL 
       46  LARGE CUT OUT FOR DISH 
       47  TRAY 
       48  RAISED EDGE ON TRAY 
       49  APRON ON TRAY 
       50  OPENINGS IN TRAY FOR DOWELS 
       51  CUTOUT 
       52  DEPRESSION 
       53  CHAINS TO HOLD DOWELS 
       54  LADDER FASTENER 
       55  FASTENING CLIP UPPER 
       56  FASTENING CLIP LOWER 
       57  STRUT 
       58  VERTICAL SIDE 
       59  STEPPED SIDE 
       60  FLAT TOP 
       61  SPRING LOADED CATCH 
       62  OPENING FOR CATCH 
       63  OUTSIDE CORNER 
       64  INSIDE CORNER 
       65  TREE 
       66  SECOND LADDER FASTENER 
       67  UPPER CLIP 
       68  LOWER CLIP 
       69  OPENING IN CLIP 
       70  STRUTS 
       71  SPRING 
       72  RING ON CONNECTING PIN 
       73  THREADED END OF PIN 
       74  SHAPED OPENING FOR PIN 
       75  BOTTOM WALL OF FRAME

Technology Classification (CPC): 4