Abstract:
A ladder having top, bottom, first and second rails and a non-slip portion selectively attached to the ladder for preventing the ladder from slipping when disposed vertically against a wall or other elevated structure. A method of applying a non-stick surface is also disclosed.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates generally to an apparatus and method for introducing a non-slip attachment to ladders.  
         [0003]     2. Description of Related Art  
         [0004]     Ladders are used by a wide variety of people (“users”) for numerous applications. Users include those who use ladders on a daily basis, such as tradesman, skilled and unskilled laborers, as well as those who only use ladders sporadically, such as homeowners. Further, most commonly, ladders are made out of metal, wood and fiberglass, while other ladders are known to be composed of other materials. As typically designed, ladders have a bottom, top, two sets of outside support rails and a series of rungs serially spaced between the two support rails. A common use for ladders is to provide a means for scaling buildings. To scale a building, a user positions a ladder against a building such that the top of the ladder rests on the upper edge of the building and the base is located some distance away from the base of the building. Critical to the stability of the ladder is both the condition of the surface for which the base of the ladder is placed, and the condition of the upper edge of the building on which the upper portion of the ladder rests.  
         [0005]     Unfortunately, the number of choices typically available for placing both the base of the ladder and the location for leaning the ladder against a building are often limited and are often less than optimal. For example, buildings are often known to contain functional or decorative treatments at their top edge including gutters, fascia, copings, or other such features. Such treatments are characterized by their low friction or otherwise relatively slippery surfaces. Such low friction surfaces are generally known to provide little resistance to the lateral shifting of the ladders resting thereon and thus are known to introduce increased physical dangers for those attempting to scale such buildings. To compensate for these greater dangers, ladder users are required to take extra precautions to reduce the chance that the ladder will shift laterally along the building. Such precautions are generally limited to the choosing of the best location to place the ladder, considering the best combination of base locations and building resting locations. Unfortunately, what may first appear to be an ideal surface for placing a base of the ladder, may only later, during actual use, be found to be problematic. Problem base surfaces often result in the unexpected shifting, sinking, or slipping of the base of the ladder, which, in turn, causes the portion of the ladder resting on the slippery low friction surface to shift or slide in a lateral direction across the building. Any such movement is undesirable and represents a threat to the physical well being of the ladder user. Further, the lack of adequate friction between the ladder and the building surface requires that the base of a ladder provide a large portion of the lateral stability of the ladder, as such, any problems with the base surface is amplified when the ladder rests upon a low friction surface on a building.  
         [0006]     In an effort to reduce such dangers, and to reduce damage that occurs to building treatments by the resting of ladders thereupon, new ladder designs have been proposed. One proposal includes the use of load-dispersing bumpers on portions of ladder rails for resting against the top edge of the target buildings. This design includes the use of a bumper having a pair of flexible, resilient, load-dispersing bumpers, affixed to the ladder rails. The bumpers are described as being attached to the ladder by an external means. More specifically, the bumpers are described as being attached to the ladder by any one of the following: application of an external adhesive, double sided tape, hook and loop material, or multiple dome-topped pins dimensioned to fit within holes in the bearing surface. An alternative to this design includes using a strip of bumper material that is attached to the ladder by a large retaining clip. Another alternative design includes a bumper that is designed to clamp around the outside of the rail. Each of the above-described designs either require the use of an additional means to attach the bumpers to the ladder, or require the bumper itself to clamp onto a portion of the ladder. Other non-slip ladder solutions have been proposed, but such designs are generally limited to designs where the non-slip member is attached to the ladder at a location other than the surface of the side rails and/or otherwise attach such non-slip member in some type of clamping or rail-surrounding mechanism. In addition, many existing designs are applicable only to specific ladder designs and, therefore, cannot be used in conjunction with the standard ladders, thus, ignoring the safety threats presented by the vast majority of ladders in use today and which will continue to be used for years into the future.  
         [0007]     As demonstrated above, a need exists for a simple, universal, non-slip, easy to apply, ladder attachment that provides lateral slip resistance between the ladder and the target building and that can be affixed to a wide variety of existing ladders. Desirably, the new attachment is capable of being easily installed by layman or persons otherwise without significant mechanical experience. Further, it would be desirable if the new attachment had the capability of being reapplied in response to an earlier applied attachment having experienced heavy wear and tear.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     A method and apparatus attaching a non-slip tape portion to a rail of a ladder. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0009]      FIG. 1  is a side elevational view of a ladder having non-slip tape attached to its upper portion and representing one embodiment of the invention;  
         [0010]      FIG. 2  is a side perspective view of a ladder having non-slip tape attached to its upper portion and representing one embodiment of the invention;  
         [0011]      FIG. 3  is a side elevational view of the non-slip tape extending along a linear path from one of the embodiments of the invention;  
         [0012]      FIG. 4  is a side elevational view of the non-slip tape extending along a curved path from one of the embodiments of the invention;  
         [0013]      FIG. 5  is a side elevational view of an extension ladder having non-slip tape attached to an upper portion of its upper extension and representing an embodiment of the invention;  
         [0014]      FIG. 6  is a side perspective view of an extension ladder having non-slip tape attached to an upper portion of its upper extension and representing an embodiment of the invention;  
         [0015]      FIG. 7  is a side elevational view of an extension ladder having non-slip tape attached to the upper portions of its upper and lower extensions and representing an embodiment of the invention; and  
         [0016]      FIG. 8  is a side perspective view of an extension ladder having non-slip tape attached to the upper portions of its upper and lower extensions and representing an embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]     The embodiment shown in  FIG. 1  includes a ladder  100  having a fixed height H, a top portion  120 , a bottom portion  122 , a first rail  102  having a first side  106  (building side) and a second side  104  (user side). Further attached to the first side  106  of the first rail  102  is a non-slip tape segment  110  having a length L. The non-slip tape segment  110  is located at a position along the first side  106  of first rail  102  such that when the ladder  100  is resting against a building, the ladder  100  rests against such building along its non-slip tape segment  110 . Further,  FIG. 2  shows the additional components, including a second rail  202  with a first side  206  and a second side  204 . Attached to the first side  206  of the second rail  202  is a non-slip tape segment  210  having a similar length L to that of the corresponding non-slip tape segment  110 . Although  FIG. 2  indicates a second non-slip tape segment  210 , other embodiments require only the first non-slip tape segment  110 .  
         [0018]     The non-slip tape segment  110  is further described in  FIGS. 3 and 4 . Further, the non-slip tape segments  210 ,  710 ,  810 ,  912  and  1012 , described herein, if used, are known to have similar properties as those associated with the non-slip tape segment  110 , although such properties may vary among the different non-slip tape segments  110 ,  210 ,  710  and  810  included on any one embodiment. The non-slip tape segment  110  has a thickness of T and is made up of a material side  502  (“material layer”) and an adhesive side  504  (“adhesive layer”). Further, the material side  502  has a non-slip outer surface  506 . Because the non-slip tape segment  110  comes with an adhesive side or layer  504 , i.e., the adhesive layer is pre-applied, no additional securing means outside of the tape itself is required to secure the non-slip tape segment  110  to the ladder  100 . In one embodiment, the adhesive side  504  is originally covered by a tape cover or backing (not shown) which is peeled off before such non-slip tape segment  110  is applied to the first side  106 . In another embodiment, the non-slip tape segment  110  is originally wound upon a tape roll as part of a larger accumulation of non-slip tape (not shown) such that the adhesive side  504  of one portion of the non-slip tape segment  110  adheres to the material side  502  of another portion of the non-slip tape segment  110 . In one embodiment, the non-slip tape segment  110  is semi-rigid. In another embodiment, the non-slip tape segment  110  is pliable.  
         [0019]     The non-slip tape segment  110  is located and/or applied to a location determined to represent that portion of the first side  106  of the first rail  102  such that when the ladder  100  is placed up against a target building, the non-slip tape segment  110  rests upon the edge of that building. More specifically, one particular method for applying the non-slip tape segment  110  to a ladder  100  includes the steps of identifying a building contact portion of the first rail  102  and applying the non-slip tape segment  110  to the building contact portion of the first rail. With the tape securely fastened to the first side  106  and with the ladder  100  leaning against the top edge of a building where the non-slip tape segment  110  is between the building edge and the first side  106 , the non-slip outer surface  506  maintains a lateral frictional force with the building edge such that the non-slip tape segment  110  resists the ladder  100  from moving in a lateral direction along the building edge. As such, the ladder  100  tends to maintain its location on the top edge of the building in comparison to other ladders absent such non-slip structures that would tend to experience lateral movement under similar loads and forces. Further, a exemplary method for using the ladder  100  includes resting the ladder against a building, such that the anti-slip tape is located between the first side of the first rail of the ladder and the building, and then placing weight on a rung of the ladder  100 , including a user stepping on the first rung and subsequently scaling a length of the ladder  100 .  
         [0020]     Although the embodiments shown in  FIGS. 1 and 2  use a non-slip tape segment  110  having a thickness T of less than {fraction (1/16)} of an inch, other embodiments use the non-slip tape segments  110  having a thickness T of greater than {fraction (1/16)} of an inch. In one embodiment, the specific non-slip tape segment  110  is chosen from the 3M™, Safety-Walk™, Medium Resilient Tapes and Treads 300 Series known to have a dynamic coefficient of friction for a dry rubber surface of approximately 1.06, plus or minus 25%, and a static coefficient of friction of approximately 1.06, plus or minus 25%. In another embodiment, the specific non-slip tape segment  110  is chosen from the 3M™, Safety-Walk™, Fine Resilient Tapes and Treads 200 Series known to have a dynamic coefficient of friction for a dry rubber surface of approximately 1.29, plus or minus 25%, and a static coefficient of friction of approximately 1.38, plus or minus 25%. Another embodiment uses a non-slip tape segment  110  having foam rubber type qualities. Generally, although a number of embodiments use different types of non-slip tape segments  110 , such embodiments each have a non-slip tape segment  110  that provides, when attached to a ladder  100 , additional lateral friction between such first rail  102  and the building on which it leans, in comparison to those ladders without tape segment  110  attached thereto.  
         [0021]     In one embodiment, the ladder  100  has a height H such that the first side  106  of the top portion  120  rests upon an upper edge of a building when placed there against. Further, the portion of the first side  106  that rests upon the building edge is that part of the first side  106  that is shown in  FIG. 1  as being covered by the non-slip tape segment  110 . In addition, and as shown in  FIG. 2 , the non-slip tape segment  210  is shown located on the second rail  202 , and having substantially the same length as the non-slip tape segment  110 , and located in substantially the same location along its corresponding second rail  202 , such that when the ladder  100  is rested against the target building that its non-slip tape segment  210  on its first side  206 , also rests upon the upper edge of the building. Although two non-slip tape segments  110  and  210  are shown attached to the ladder  100  in the embodiments shown in  FIGS. 1 and 2 , other embodiments use only a single non-slip tape segment  110  on one of the ladder  100  rails  102  and  202 .  
         [0022]     In operation, a ladder user would identify a target building that the ladder user wants to scale. Then, the ladder user would place the ladder  100  such that its bottom portion  122  would be located on a firm, flat, relatively non-slippery surface, and its top portion  120  would be rested against the top of such building where the non-slip tape segment  110  would be in contact with such top building edge. Once so placed, the user would ascend up the ladder, rung by rung, until the user reached their desired height. Throughout this procedure, and in contrast to standard ladders not having the non-slip tape segment  110  or other similar attachment, the non-slip tape segment  110  provides a gripping function that prevents the ladder  100  from moving in a lateral direction in comparison to the target building. As such, any conditions, (e.g., an unstable ladder footing, the shifting of weight moving up the ladder, etc.), that would otherwise urge a standard ladder to move laterally in relation to a building on which it rests, is countered to some degree by the non-slip tape segment  110  attached to the ladder  100 .  
         [0023]      FIGS. 5-8  show embodiments that utilize an extendible ladder design. Here, rather than the simple two-rail design as shown in  FIGS. 1-2 , an inter-sliding four rail design is used. As shown in  FIGS. 5 and 6 , such extendable ladder  700  designs include a ladder having an upper first rail  702  and a lower first rail  704 . Upper first rail  702  having upper and lower portions  750  and  752 . Lower first rail  704  having upper and lower portions  756  and  758 . The upper first rail  702  has a first side  708 . The lower first rail  704  has a first side  709  and a second side  705 . Further, attached to the first side  708  of the upper portion  750  of the upper first rail  702  is the non-slip tape segment  710 . As with the other embodiments described above, such non-slip tape segment  710  is positioned to rest against a target building top edge. Further, as the upper first rail  702  moves in one direction P 2  in relation to the lower first rail  704 , and the lower first rail  704  moves in another direction P 1  in relation to the upper first rail  704 , the non-slip tape segment  710  does not prevent or impede the movement of such rails. Further, each of the paths followed by upper and lower first rails  702  and  704  in the respective directions P 1  and P 2  are parallel to one another.  
         [0024]      FIG. 6  shows a perspective view that reveals additional components including upper second rail  802  and a lower second rail  804 . The upper second rail  802  has a first side  808 . The lower second rail  804  has a first side  809  and a second side  805 . Upper second rail  802  having upper and lower portions  750  and  752 . Lower first rail  804  having upper and lower portions  756  and  758 . Further, attached to the first side  808  of the upper portion  750  of the upper first rail  802  is the non-slip tape segment  810 . As with the other embodiments described above, such non-slip tape segment  810  is positioned to rest against a target building top edge. As the upper second rail  802  moves in relation to lower second rail  804 , the non-slip tape segment  810  does not prevent or impede the movement of such rails,  802  and  804 , in relation to one another.  
         [0025]     Although embodiments utilizing an extendable ladder design have been described in correlation with  FIGS. 5 and 6 , and such embodiments have been described as using two pairs of sliding rails, other embodiments (not shown) that are extendable, use a plurality of pairs of sliding rails rather than just two, while yet other embodiments (not shown) use three or more rails associated with any particular rung rather than to two rails shown. In all such embodiments, at least one of the rails therein which is intended to rest on the edge of a building has located thereon a non-slip tape segment for providing the lateral stability described above.  
         [0026]     As shown in  FIGS. 7 and 8 , additional non-slip tape segments  912  and/or  1012  can be added to achieve a ladder  900  with additional non-slip tape segments  912  and  1012  attached to the upper portions  756  of rails  704  and  804  on their respective first sides  709  and  809 .  
         [0027]     In operation, a user operates the extendable ladders  700  and  900  similarly to that of single piece ladders  100 . However, as extendable ladders, such ladders  700  and  900  operate like any standard extendable ladders, with the only exception being the placement of the non-slip tape segments located thereon and where such non-slip tape segments are meant to rest against the top edge of a target building. Further, ladder  900 , having additional non-slip tape segments  912  and  1012  located near the upper portions  756  of rails  704  and  804 , is further designed to be used on smaller buildings and structures where such non-slip tape segments  912  and  1012  can be used to rest against such target buildings and structures, rather than the non-slip tape segments  710  and  810 , for example, where the upper first and second rails  702  and  802  are substantially retracted in relation to the lower first and second rails  704  and  804 .  
         [0028]     While only a few embodiments and aspects of the invention have been described above, including the preferred embodiment, those of ordinary skill in the art will recognize that these embodiments and aspects may be modified and altered without departing from the central spirit and scope of the invention. Thus, the embodiments and aspects described above are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced herein.