Patent Abstract:
An outrigger stabilizer combined with a ladder includes a telescoped outer tube and inner elongated member with a one way brake freely allowing telescoping movement of the inner member out of the outer tube to automatically adjust to engage the ground but instantly locking together when any collapsing movement is attempted to brace the ladder in any adjusted position.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of U.S. Ser. No. 10/819,476, filed on Apr. 4, 2004 and also claims the benefit of U.S. provisional Ser. No. 60/461,499, filed Apr. 9, 2003 since it was claimed in the parent application, U.S. Ser. No. 10/819,476. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention concerns ladder stabilizers which act to brace a ladder to prevent falls when a ladder leaned against a wall or other structure slides to either side step ladder also can tip over to either side as when a user shifts his or her weight or leans too far to the side.  
         [0003]     This hazard very commonly causes falls, particularly where a ladder rests on an uneven surface. Numerous ladder stabilizers have been devised to avoid this problem, including mounting telescoping outriggers to each side of a ladder, sloping downwardly from a point of attachment to each ladder stile and having an end engaged with the ground or other supporting surface.  
         [0004]     The problem with these prior outrigger stabilizers is the need to manually carefully adjust the length of each outrigger to securely engage the surface of each situation. This is a time consuming chore and thus is often not done or only done haphazardly.  
         [0005]     Another problem is that the adjusted length is sometimes not well secured or a thumbscrew becomes loose, allowing free telescoping of the outrigger components to occur and this defeats the purpose of the stabilizer. Also, the ladder may shift as the user moves on the ladder which could shift the stabilizer lower end where it may not reach the ground.  
         [0006]     It is important that such a stabilizer be simple, convenient, failsafe, and low in cost to manufacture.  
         [0007]     It is the object of the present invention to provide an outrigger type ladder stabilizer which does not require that manual adjustments be made and is very securely held in each adjusted condition.  
       SUMMARY OF THE INVENTION  
       [0008]     The above object and others which will become apparent upon a reading of the following specification and claims are achieved by an outrigger stabilizer comprised of a pair of telescoped tubes with an inner tube slidable in an outer tube connected at its upper end to one side of the ladder, extending down laterally therefrom. The two tubes are interconnected with a one way acting brake which allows the inner tube to freely telescope out from the outer tube, but instantly locks to the outer tube when any movement to telescope the inner tube back into the outer tube is attempted. This provides an automatic length adjustment and a secure locking of the stabilizer in each adjusted length. The one way brake comprises an arrangement wherein the upper end of the outer lower tube mounts an inclined annular disc having a hole through which the inner tube is loosely fit. A metal strip fixed to the upper end of the outer tube is formed with an inclined reaction tab which engages the bottom of one side of the annular disc so that it assumes a downwardly inclined orientation as the opposite side of the disc tilts down under its own weight.  
         [0009]     The inclined annular disc acts as a one way acting brake while it allows the outer tube to telescope out from the outer tube but instantly wedges to the inner tube and to lock the two tubes together when forces are exerted on the stabilizer tending to telescope the two tubes back together. The friction between the side of the inner tube and one edge of the disc hole causes a wedging action to instantly occur. The length adjustment occurs automatically by gravity when the ladder is placed against a vertical support and the lower tube descends until the ground or other surface is encountered by its bottom end. At the same time, the locking action is very secure and will not loosen.  
         [0010]     The inner tube may be quickly released to allow telescoping back into the outer tube by lifting up on the tilted down side of the disc.  
         [0011]     The strip may also have an upper tab sloping back inwardly which causes the annular disc to tilt in the opposite direction and prevents escape of the inner tube when the stabilizer is inverted. A disc keeper element can also be provided.  
         [0012]     Any tipping action is positively resisted by attaching an outrigger stabilizer on each side of the ladder.  
         [0013]     An outrigger stabilizer according to the invention can be quickly mounted to each side of the ladder by a cross tube passed through a selected rung hole and each end received in a hole on the upper end of the inner tube, retained therein with an end cap.  
         [0014]     The stabilizer may also be secured to a step ladder by an adjustable clamp mounted to the top of each upper tube and gripping a respective step ladder stile. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a pictorial view of an extension ladder having a pair of outrigger stabilizers according to the invention installed thereon and deployed on the adjacent ground surfaces.  
         [0016]      FIG. 1A  is a pictorial exploded view of the outrigger stabilizers shown in  FIG. 1 , with the extension ladder on which they are installed.  
         [0017]      FIG. 2  is an enlarged partially sectional fragmentary view of the upper end of the telescoped tubes included in the stabilizer shown in  FIGS. 1 and 1 A and a one way brake associated therewith.  
         [0018]      FIG. 3  is a pictorial view of the upper end of the telescoped tubes and a second form of the one way brake shown in  FIG. 2 , shown rotated towards the viewer.  
         [0019]      FIG. 4  is a pictorial view of the upper end of the outer tube with phantom lines showing a section to be removed in manufacturing an integral reaction tab included in an alternate embodiment of the one way brake.  
         [0020]      FIG. 5  is a pictorial view of a step ladder having an outrigger stabilizer according to another embodiment of the invention installed thereon.  
         [0021]      FIG. 6  is an enlarged exploded pictorial view of the upper end of the outrigger stabilizer and adjacent portions of the stepladder shown in phantom lines.  
         [0022]      FIG. 7  is a sectional view of portions of another embodiment of the invention.  
         [0023]      FIG. 8  is a pictorial view of the upper end of the outer tube shown in  FIG. 7 .  
         [0024]      FIG. 9  is a partially sectional and pictorial view of portions of yet another embodiment of the invention.  
         [0025]      FIG. 10  is a sectional view through the lower tube shown in  FIG. 9 .  
     
    
     DETAILED DESCRIPTION  
       [0026]     In the following detailed description, certain specific terminology will be employed for the sake of clarity and a particular embodiment described in accordance with the requirements of  35  USC 112, but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims.  
         [0027]     Referring to the drawings, and  FIGS. 1-4 , an extension ladder  10  is shown leaning against a building wall  12 , the ladder  10  resting on the adjacent ground surface. A pair of outrigger stabilizers  14  according to the invention each have an attachment at their upper end to the side of a respective ladder stile  16 .  
         [0028]     This attachment is preferably accomplished by installing a cross tube  18  through one of the normally hollow rungs  20  of the ladder  10  at an intermediate height thereon.  
         [0029]     Each outrigger stabilizer  14  extends at an outward angle and rests on the adjacent ground surface so as to provide a bracing of the ladder  10 , resisting any tendency to slide or tip sideways.  
         [0030]     Each outrigger stabilizer  14  automatically adjusts in length to have its lower end brought into secure contact with the ground surface regardless of the unevenness of the ground surface adjacent the ladder  10 .  
         [0031]     This is accomplished by the telescoping out of an inner elongated member comprised of an inner tube  22  slidably received in an outer tube  24  ( FIG. 1A ) thickness as the outer tube  24  drops down from its own weight. These 22, 24 tubes are constructed of metal, such as of steel or aluminum and have a sufficiently heavy wall to provide a sturdy support, able when extended to resist the force exerted by the ladder  10  and if any tendency to tip sideways occurs.  
         [0032]     The inner tube  22  has a flattened tip  25  which has a hole  23  formed therein sized to receive the cross tube  18 . A pair of retainer end caps  19  are installed to keep the same on a respective tube end. The lower end of each outer tube  24  has a nonskid tip  27  installed thereon.  
         [0033]     A one way acting brake  26  is installed on the upper end of the outer tube  24  which allows the inner tube  22  to freely telescope out of the outer tube  24 , as the outer tube  24  drops away under the influence of gravity but instantly engages to rigidly connect together the tubes  24 ,  26  to resist any telescoping together of these tubes  22 ,  24  if a pushing force is exerted on the upper tube  22  after the outer tube  24  contacts the supporting surface.  
         [0034]     Each one way acting brake  26  comprises an annular disc  28 , preferably of steel which is held at an inclined angle on the upper end of the outer tube by an upwardly and outwardly angled reaction tab  30  formed in a metal strip  32  affixed as by welding or by other means to one side of the upper end of the outer tube  24 . The reaction tab  30  contacts the bottom surface of the left side of the disc  28  when the stabilizer  14  is upright.  
         [0035]     An upwardly and inwardly angled tab  34  may also be formed at the end of the strip  32 , contacting the left side of the disc  28  when the stabilizer  14  is inverted to prevent escape of the inner tube  22 .  
         [0036]     As noted, the hole  29  in the annular disc  28  is sufficiently larger than the inner tube  22  to allow the same to assume the tilted downward orientation shown in  FIG. 2 .  
         [0037]     Since the inner tube  22  is held on the cross tube  18 , the outer tube  24  will freely drop down, sliding along the inner tube  22  which is thereby telescoped out of the outer tube  24 . The annular disc  28  assumes a downwardly angled orientation, tilting down to the right as viewed in  FIG. 2 , under the influence of gravity and the left side is held up by engagement with the reaction tab  30 . Thus, the friction between the edge of the hole  29  in the annular disc  28  tends to lift and straighten the disc  28 , increasing the clearance between the upper tube  22  and the disc  28  when the inner tube  22  is telescoping out of the outer tube  24 .  
         [0038]     On the other hand, when the inner tube  22  starts to move relatively towards the outer tube  24  to be telescoped thereinto, friction between the inner tube  22  and the edge of the hole in the disc  28  immediately drives the right side of the disc  28  further down to increase the inclination thereof to eliminate the clearance between the hole  29  in the annular disc  28  and create a wedging between inner tube  22  and the disc  28  since the disc  28  is restrained by the reaction tab  30 . This positively prevents the inner tube  22  from moving into the outer tube  24 .  
         [0039]     The reversely angled reaction tab  34  creates the same action if the ladder  10  is angled down as during handling so that the inner tube  22  will be locked and not fall out of the outer tube  24  inadvertently.  
         [0040]      FIG. 3  shows another form of the one way acting brake  26 A. In this version, the strip  32 A is formed only with the outwardly and upwardly angled tab  30 A. A cotter pin  36  is installed in holes through the disc perimeter and the tab  36  to retain the disc  28 . The fit thereon is loose enough to allow reversing of the inclination of the annular disc  28  to capture the inner tube  22  when inverted.  
         [0041]      FIGS. 4A and 4B  show an alternate construction in which the upper end of the outer tube  24  has a portion  38  cut away to leave a segment  40 . That segment is formed to create an integral strip  32 B and tabs  30 B and  34 B.  
         [0042]      FIGS. 5 and 6  show the mounting of an outrigger stabilizer  14  mounted to a stepladder  42  by a stile clamp  48 . The clamp  44  comprises a pair of U-shaped pieces  46 ,  48  fit together to be slidably adjustable to various sized stiles.  
         [0043]     A slot  50  and a hole  52  receive a screw  54  which also passes through a drilled hole in the ladder stile  56 , with a nut  58  tightened to secure the same in any adjusted position to fit the same to stiles of various widths.  
         [0044]     Thus, a simple but very convenient to use outrigger stabilizer has been provided which is also very reliable in preventing sideways tipping of a ladder to alleviate a major source of ladder accidents.  
         [0045]     In one successful design, the tabs  30  and  34  were about three quarters of an inch long, with about a 20° angle there between. The lower side of the inclined annular disc  28  was located to have about one quarter of an inch clearance with the top edge of the outer tube  24  to insure that contact would not occur and wedging engagement with the inner tube  22  was assured. The outer tube  24  was 57.5 inches long and the inner tube  22  was 60 inches in length to insure that an upper end protruded therefrom when the two tubes were collapsed together.  
         [0046]      FIGS. 7 and 8  show a simplified form of the invention in which an annular disc  60  is not mounted to either outer tube  62  or inner tube  64 . Rather, the annular disc  60  is simply slidably held on the inner tube  64 , with the inside diameter of the annular disc  60  being larger than the outside diameter of the inner tube  64  to allow it to incline as shown sufficiently to create a wedging action to the inner tube  64  when restrained on one side by an elevated crest  66  on the outer tube  62 .  
         [0047]     This crest  66  is created by cutting off the outer tube at an angle as shown. The annular disc  60  thus drivingly engages the lower tube  62  by contact with the crest and is wedged to the inner tube  64  when the inner tube  64  is slid into the outer tube  62 . When the inner tube  62  slides out, no engagement of the disc  60  occurs, with either tube. Thus, a one way brake is provided.  
         [0048]     The crest  66  is preferably formed over and outwardly to create a larger dimension across the outer tube  62 . This prevents the outer tube  62  from entering the inside diameter of the annular disc  60 .  
         [0049]      FIGS. 9 and 10  shows a variation in which the lower tube  62 A is extruded with a series of outside ribs  68  which create a larger dimension across the lower tube  62 A.

Technology Classification (CPC): 4