Abstract:
Provided is a plugging device for covering the open ends of the rungs of a ladder. The device includes a pair of plug members and a connection member. The plug members include a plug body to cover the open ends of the rung and sit adjacent to the ladder rail and a gasket configured for insertion into the ladder rung. The gasket is made of a flexible, compressible material to fit snugly within the open end of the ladder rung. The connection member is configured to be passed through the ladder rung and is elastically biased to pull the pair of plug members towards one another, when connected, through the ladder rung and secure them in place in the open ends.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to terminal end plugs for tubular members. In particular, this invention relates to a device and method for covering the terminal, open ends of a ladder rung. Generally, various service vehicles, especially service vans, must carry ladders to worksites. These ladders may be step ladders or extension ladders. While some ladders have platform, open-channel steps, many ladders, especially extension ladders, employ hollow rungs that extend between the ladder rails. The ends of these hollow rungs are generally not capped. Ladders are normally carried in an uncovered state on the roof of such service vehicles, where the ladders are usually oriented such that the rungs lie in a transverse, or perpendicular, nature to the direction of travel of the vehicle. Consequently, the ambient air, as the vehicle is moving forward, passes over the open ends of the ladder rungs. As the air passes over the open ends of the ladder rungs, the open ends act as a pair of embouchures, causing substantial acoustic vibration and noise. The noise is especially noticeable in vans that do not have insulation on the inside of the roof panel, which is usually the case with service vans. 
     Accordingly, there is a need for a system and a method to cover the open ends of the ladder rung for the purpose of substantially quieting the noise produced when air travels across these open ends as the carrying vehicle is in motion, and for otherwise protecting the open channels. 
     SUMMARY OF THE INVENTION 
     The present invention provides such a system and method for substantially quieting the noise produced by the open ends of the ladder rung while in motion. One embodiment according to the present invention includes a pair of plug members that interface to the open ends of a ladder rung throughbore. The plug members include a plug body and a flexible gasket. The plug body may be a convex disk, formed of a hard plastic material. The plastic material of the plug body may have an opening in which to insert a design or logo, serving an aesthetic purpose, or other purposes such as advertisement. 
     Attached to the inner surface of the plug body is the gasket. The gasket may be formed of a soft, flexible material, such as water-resistant foam. The flexible foam gasket is preferred such that it may be inserted and fit snugly into rung openings of various shapes and sizes. 
     Also found on the inner surface of the plug body is an anchor attachment point. The anchor attachment point may attach and anchor, having on its distal end an attachment mechanism, such as a loop to which a corresponding hook on a connection member may be attached. The connection member draws the pair of plugs toward each other within the ladder rung. In a preferred embodiment the connection member is a bungee cord. The connection member may be drawn through the ladder rung by passing a threading mechanism through the rung, attaching it to the free end of the connection member, and pulling the free end back through the rung to attach to the attachment mechanism on the other plug member. 
     At least one end of the connection member must be releasably attached to the corresponding plug body, in order that the cord may be threaded through the ladder rung to connect to the second plug body on the opposing end. In one embodiment, both ends of the connecting member are releasably attached to the plug body by hook and loop configuration. 
     While a single plug may be provided as a stand-alone unit, it is preferred to provide at least two plugs and a connection member in a kit form. Furthermore, it is preferred that a plurality of pairs of plugs be provided in a kit form. Such kits may be provided in, for example, 16-rung kits, 20-rung kits, 24-rung kits, 28-rung kits, etc., which may correspond to the length of the ladder on which the plugs will be used. In a 16-rung kit, at least 32 plugs may be provided, and at least 16 connection members may be provided. Extra units may be provided to accommodate specific ladder types. The kit may further include the threading mechanism to draw the end of the elastic biasing member through the ladder rung and labels to be inserted into the plug body, viewable on the side of the ladder. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a ladder with an embodiment of a plugging device according the present invention. 
         FIG. 2  is a perspective view of a single ladder rung from  FIG. 1  with the embodiment of a plugging device according to the present invention. 
         FIG. 3  is a perspective view of a plug body according to the present invention. 
         FIG. 4  is a cross-sectional view of the plug body of  FIG. 3 . 
         FIG. 5A  is a perspective view of the plug body of  FIG. 3  in cooperation with a connection member according to the present invention. 
         FIG. 5B  is a perspective view of an alternative embodiment of a plug body according to the present invention. 
         FIG. 6  is a side elevation view of a ladder rung open end. 
         FIG. 7  is a side elevation view of the ladder rung open end of  FIG. 6  covered by a plugging device according to the present invention. 
         FIG. 8  is a perspective view of a plugging device according to the present invention being placed in an open end of a ladder rung. 
         FIG. 9  shows an embodiment of a kit according to the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims. 
       FIG. 1  shows a typical utility ladder having a hollow rung  12  and the rung  12  having a pair of open ends  14 .  FIG. 1  also shows some of the hollow rungs  12  having a plugging device  10  according to the present invention covering open ends  14 . 
       FIG. 2  shows a plugging device  10  having a pair of plug members  20 , coupled together by a connection member  30 , being used to plug the open ends  14  of the ladder rung  12 . 
       FIG. 3  shows a plug member  20  according to the present invention. The plug member  20  has a plug body  22  and a gasket  24 . The plug body  22  is preferably formed of a molded thermoplastic material, but may otherwise be any material suitable for covering the open ends  14  of the ladder rung  12 , and strong enough to maintain its shape when the force of the connection member  30  is applied. In the preferred embodiment, the plug body  22 , or at least the outer portion thereof, is generally convex. The convex nature of the plug body  22  allows for reduced air resistance and aids in reducing wind noise. The plug body  22  may be disc-like in shape, but it may also be a square, rectangle, or any other shape that is desired by the manufacturer or user. The plug body  22  is configured to be positioned adjacent to the outer rail  15  of the ladder, as shown in  FIGS. 1 and 2 . The plug body  22  is preferably sized and configured to at least substantially (&gt;50%), but preferably completely cover the rung opening  14  (illustrated in  FIG. 7 ). The plug body  22  forms an outer edge  21 . As shown in  FIG. 4 , the plug body  22  may be configured in layers  22   a ,  22   b  with an opening  23  in which to slide a label  60  or other decorative object, which provides an aesthetically pleasing and uniform look, as well as provides advertisement opportunities or serves other purposes. The opening  23  may extend through the body  22  from one portion of the outer edge  21  to an opposing side of the outer edge  21 , with closed areas therebetween. Alternatively, up to half of the outer edge may provide access to opening  23  with the other at least half of outer edge  21  having layers  22   a ,  22   b  connected and closed.  FIGS. 2-4  show this preferred embodiment where only a portion of outer edge  21  provides access to opening  23 . The opening  23  is at least large enough to accommodate sliding a label  60  or other decorative object within the opening. The body  22  may or may not have the opening  23 , and the opening  23  may or may not contain a label  60  or other decorative object. 
     The opening  23  may be sealed in a water-tight fashion in order to prevent the access of moisture, such as rain or other precipitation, or moisture in the air from entering the opening  23 . Such water-tight sealing may be provided by a plug body case  16  that covers the outer layer  22   a , the outer edge  21 , and at least a portion of the bottom layer  22   b , as shown in  FIG. 4 . The plug body case  16  may be constructed of a flexible, elastic material such as silicone rubber. The opening  23  may also be sealed via a cover tab  17  that is hingedly connected to the plug body  22 , such as to the outer edge  21  as shown in  FIG. 5A . The cover tab  17  preferably comprises a cover portion  17   a  and an insertion portion  17   b , such that that cover portion  17   a  covers the opening  23  and at least a portion of the surrounding area, and the insertion portion  17   a  can be partially inserted into the opening  23 . The cover tab  17  is preferably made of a flexible material, such as silicone, but may also be constructed of a hard plastic material. The water-tight sealing may also be provided by an o-ring configuration, as shown in  FIG. 5B . In this embodiment, the plug body  23  may have a groove  18  formed in the outer edge  21  about the circumference of the plug body  23 . The groove  18  is configured to receive an o-ring  19 , or rubber band type device, to at least partially extend about the perimeter of the outer edge  21  and cover the opening  23 . In addition to these embodiments of water-tight sealing, other means may be used to close off the opening  23  and prevent moisture from entering. 
     In an alternative embodiment, the plug body  22  may have a logo or other decorative element printed or stamped directly on or formed in the thermoplastic material of the outer layer  22   a  of the plug body  22 , or it may be printed or stamped on a sticker or a plug body cover, such as the flexible plug body cover  16  discussed above, which covers the outer layer  22   a  of the plug body  22  to provide the aesthetic or advertisement feature of the plug body  22 . 
     The gasket  24  of the plug member  20  is affixed to the inner surface  27  of the plug body  22 . The gasket  24  is configured to fit into the opening  14  of the ladder rung  12 . The gasket  24  is preferably formed of a soft, flexible material so it may be fit into rungs  12  of various shapes and sizes. The material is preferably water resistant to maintain the integrity of the gasket  24  in all weather conditions. The gasket  24  is preferably sized and configured for the broadest portion of the gasket  24  to be substantially the same shape and dimension as the ladder rung opening  14 , or slightly larger than the opening  14  such that a tight fit is created when the flexible gasket material is inserted and compressed within the ladder rung opening  14 . The gasket  24  may also be frustoconical in shape, with the broadest portion of the gasket  24  being situated adjacent to the inner surface  27  of the plug body  22  and the narrowest portion disposed at a distal end opposite of the broad portion. This accommodates insertion into the ladder rung, allowing for the narrow side to be inserted easily into the open end  14  and becoming increasingly tight as the gasket  24  is inserted fully into the open end  14 , creating a secure fit. 
     As shown in  FIG. 4 , there may be an anchor attachment point  26  generally centrally located on the plug body  22 . An anchor  25  may extend from the anchor attachment point  26  to a distal end. Between the attachment point  26  and the distal end, the anchor  25  is at least partially surrounded by the flexible gasket  24 . The distal end of the anchor  25  may contain an attachment mechanism  28 . In a preferred embodiment, the attachment mechanism  28  is a loop or hook, but may be any attachment device to which a counterpart end  36 , such as a hook, of the connection member  30  can releasably attach. Alternatively, in the plugging device  10  having a pair of plug members  20 , the attachment mechanism  28  on one of the pair of plug members  20  may be substantially permanently attached to a counterpart end  36  on the connection member  30  while the other plug member  20  provides an attachment mechanism  28  that is releasably attachable to the connection member  30 . 
     The connection member  30  preferably comprises an elastic biasing means. In the embodiments shown, the connection member  30  is a bungee cord  34  with the elastic biasing means being provided by the elastic nature of the bungee cord. The elastic biasing means may also be an elastic mechanism, such as a spring (not shown), that connects a non-elastic cord (not shown) to the attachment mechanism  28 . In another alternative, the anchor  25  may be attached to the plug body  22  in a biased relationship, such as via a spring, to provide the biased force when two plug members  20  are connected via the connection member  30 . As shown, the connection member  30  is preferably threaded through the ladder rung  12  and utilizes the elastic bias to draw the pair of plug members  20  towards each other and hold the plug members  20  securely in the ladder rung openings  14 . 
     The connection member  30 , including the elastic biasing means, may be tailored to correlate to the length of the ladder rung  12  such that the force created by the biasing connection member can maintain the pair of plug members  20  in the ladder rungs  12 , but not so great so as to prevent connection of the two plug members  20  to one another. 
     It may be advantageous for there to be uniformity in plug orientation, when multiple plugging devices  10  are used. For this, and any other reason that rotation of plug member  20  is undesirable, the plug member  20  may further include a rotation prevention member  50 , as shown in  FIG. 5B . This may be particularly useful when the ladder has D-shaped rungs. The rotation prevention member  50 , such as a longitudinal rib member  52 , is affixed to the inner surface  27  of the plug body  22  and is configured to be positioned in relative position to a flat surface of the D-shaped rung. When inserted into the ladder rung  12 , the rib member  52  may prevent the plug member  20  from turning while the gasket portion  24  is inserted into the rung  12 . Additionally or alternatively, the gasket  24 , itself, may serve as an anti-rotation member by imparting a sufficient friction force against the open end  14  of the rung  12  so as to prevent rotation by normal use or even wind during ladder transport. 
     An embodiment of the present invention may also be provided as a kit  70 , such as the kit shown in  FIG. 9 . Each kit  70  may include a plurality of plugging devices  10 . The kit  70  may include a predetermined number of plugging devices  10  made up of pair of plug members  20 , and connection mechanisms  30 , corresponding to the size of the ladder. For example, the device may be provided in 16-rung, 20-rung, 24-rung, 28-rung kits, corresponding to common ladder sizes, or may be provided with any number of plugging devices  10 , with additional, individual plugging devices  10  being available to accommodate other ladder sizes. As an example, a 16-rung kit may include 32 plug members  20 , 16 connecting mechanisms  30 , a threading device  40  to thread the connection member  30  through the rung  12 , and a page  62  of labels  60  that are either pre-printed or may be printed on by the user to be inserted into or applied to the plug body  22 , if desired. Additional, individual components may be provided separately for when an extra is desired or an element has been lost, damaged, or is otherwise unavailable. 
     Also according to the present invention, a method of using a plugging device  10  wherein at least one plugging device  10  is provided, the connection member  30 , such as a bungee cord  34 , may be positioned through the ladder rung  12 , and the plug members  20  are placed in and over the ladder open ends  14 . A threading device  40 , such as a coiled wire may be provided that may be inserted through the ladder rung  12 . The threading device  40  may be greater in length than the ladder rung  12 , such that at least a portion thereof extends on each side of the ladder rung  12  when threaded therethrough. Once threaded through the ladder rung  12 , the threading device  40  may be attached to an attachment end  36  on connection member  30 . The connection member  30 , by way of threading device  40  may then be pulled back through the ladder rung  12  thereby exposing the attachment ends  36  of the elastic mechanism  30  on the opposing open ends  14  of the ladder rung  12 . The elastic mechanism  30  may then attach to the attachment mechanism  28  on each of the plug members  20 . When the connection member  30  is attached, each of the plug member gaskets  24  may be inserted into the open end  14  of the ladder rung. The elastic or other biasing means in the connection member  30  keeps the plug body  20  over the open ends  14  of the ladder rung  12 . Additionally or alternatively, each connection member  30  may be sized and configured so as to pass through a rung  12  with little friction, which may eliminate any need or desirability of such threading device  40 . 
     The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.