Patent Publication Number: US-2006000674-A1

Title: Fall arrest system with anchorage plate

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This application is a Continuation-In-Part of U.S. application Ser. No. 10/880,347, filed on Jun. 30, 2004, incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD  
      The disclosure relates generally to ladders, such as those ladders used for “posting” or hanging advertisements on outdoor advertising billboards during which a fall arresting device, such as an arrestor hook or lanyard hook, is used as a safety device.  
     BACKGROUND ART  
      When working with relatively long ladders, such as greater than 10 feet in length, certain work safety rules require the use of a ladder fall arrest system, such as a lifebelt, friction brake, and/or sliding attachments in lieu of cage protection. An example of a type of ladder in which a safety device is required is a posting ladder. Conventional posting ladders  10  typically come in either a straight or tapered form, such as shown in  FIGS. 1A-1B , respectively. These ladders  10  are typically hooked over the top of a billboard  20  with hooks  40 , and the bottom end of the ladder is permitted to hang freely without vertical support, such as shown in  FIG. 1C . In certain instances, the bottom end of the ladder  10  is displaced horizontally from the billboard  20  by a catwalk  30 , which projects laterally from the bottom of the billboard  20  generally between about one and four feet.  
      An example of a conventional fall arrest system used with a posting ladder is disclosed by Bell in U.S. Pat. No. 5,219,039. The fall prevention system includes a waist belt/harness worn by the user that is connected to a lanyard. The lanyard is in turn connected to a safety rope via a sliding connector. The safety rope is stretched across the length of a bill board so that the sliding connector can be slid along the rope across the full width of the billboard. This system, however, must first be installed prior to use and will eventually be removed prior to the need for the safety device has ended. The process of installing and removing this system takes time and does not afford a user protection during the installation and removal process.  
      Another type of a conventional fall arrest system is illustrated is  FIG. 2 . This fall arrest system includes an attachment device  16  that is configured to be attached to either the left side rail  12  or right side rail  14  of the ladder  10 . The attachment device  16  is also configured to be connected to a hook (or other connection device) of a lanyard, which is connected to the user. A problem with this particular type of fall arrest system is evident during its actual use when a person falls. As the person falls, the lanyard pulls on the attachment device  16 , which is on one side rail  12  or the other side rail  14  of the ladder  10 . However, since the attachment device  16  is not centered relative to the hooks  40 , the force create by the fall is unevenly distributed to the hooks  40 . This can cause the ladder  10  to jerk sideways, break the side rail to which the attachment device  16  is attached, and/or break the particular hook  40  receiving the greater force. There is, therefore, a need for a fall arrest system that is not required to be installed or removed and does not have the problems attendant with conventional fall arrest systems.  
     SUMMARY OF THE DISCLOSURE  
      This and other needs are met by the present invention, which in accord with one aspect includes a ladder having a pair of opposing side rails and at least one attachment device configured to be attached to a fall arresting device. The opposing side rails have a plurality of steps disposed therebetween along substantially an entire length of the opposing side rails. The attachment device is configured to be attached to a fall arresting device and is substantially centrally disposed between the pair of opposing side rails.  
      In another aspect, the attachment device is a plate, substantially parallel to a plane defined by the opposing side rails, that extends from one of the side rails to the other side rail. The ladder may include a pair of curved members respectively extending from the pair of opposing side rails at an upper distal end of the ladder. One of the attachment devices is positioned substantially centrally along a longitudinal axis of the ladder, and another of the attachment devices is positioned substantially proximate to the upper distal end of the ladder.  
      Other aspects and advantages of the present disclosure will become apparent to those skilled in this art from the following description of preferred aspects taken in conjunction with the accompanying drawings. As will be realized, the disclosed concepts are capable of other and different embodiments, and its details are capable of modifications in various obvious respects, all without departing from the spirit thereof. Accordingly, the drawings, disclosed aspects, and description are to be regarded as illustrative in nature, and not as restrictive. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The foregoing and other features, aspects and advantages of the present concepts are described in the following detailed description which examples are supplemented by the accompanying drawings, in which:  
       FIGS. 1A-1C  are perspective views of a conventional straight posting ladder, a conventional tapered posting ladder, and a conventional straight posting ladder attached to a billboard;  
       FIG. 2  is a perspective view of a straight posting ladder with a conventional attachment device connected to a side rail of the ladder;  
       FIG. 3  is a perspective view of a ladder and fall arresting system, according to the disclosure;  
       FIGS. 4A and 4B  are perspective partial views of the ladder and upper fall arrest system shown in  FIG. 3 ; and  
       FIGS. 5A and 5B  are perspective partial views of the ladder and middle fall arrest system shown in  FIG. 3 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      In accord with the disclosed concepts, there is provided, as shown in  FIGS. 3, 4A ,  4 B, and  5 A,  5 B, a posting ladder  100  including one or more attachment devices  110  configured for attachment to a fall arrest system of a user. The attachment device  110  is not limited in the manner in which the attachment device  110  is configured to attach to the fall arrest system. For example, the attachment device  110  can include a hook or U-bracket to which, for example, a lanyard of the fall arrest system can be attached.  
      In one aspect of the ladder  100 , the attachment device  110  is a plate  106  having a centrally-disposed hole  108 . The plate  106  may also completely extend from the right side rail  103  to the left side rail  105 . The ladder  100  is not limited as to the orientation or particular location of the plate  106  on the ladder  100 . However, in a current aspect, the plate  106  is substantially parallel to a plane defined by the opposing side rails  103 ,  105 . In this manner, the plate  106  may be positioned so as to not substantially protrude from the ladder  100 . Otherwise, if the plate  106  protruded from the ladder  100 , the plate  106  could catch on objects when the ladder  100  is being positioned or even become an obstacle when the user climbs up and down the ladder  100 .  
      The plate  106  may also be positioned to the rear of the ladder  100 . As defined herein, the rear of the ladder  100  is the side opposite to where the user would climb up and down the ladder  100 . With a posting ladder  100  that includes hooks  120 , the rear of the ladder  100  is in the direction the hooks  120  extend away from the ladder  100 . By positioning the plate  106  to the rear of the ladder  100 , instances in which the plate  106  interferes with the user can be reduced.  
      The attachment device  110  is substantially centrally disposed between a pair of opposing (i.e., right and left) side rails  103 ,  105  of the ladder  100 . By positioning the attachment device  110  in this manner, the attachment device  110  transmits forces evenly to both side rails  103 ,  105 , which tends to center the ladder  100  when the fall arrest system exerts a downward force upon the attachment device  110 .  
      The manner in which the attachment device  110  is connected to the ladder  100  is not limited in any particular manner. Although the attachment device  110  may be detachable from the ladder  100 , in a current aspect of the ladder  100 , the attachment device  110  is permanently attached to the ladder  100 . The attachment device  110  is also not limited in manner in which the attachment device  110  permanently connects to the ladder  100 . For example, the attachment device  110  may be connected to right and left brackets  112 , which are in turn respectively connected to the right and left side rails  103 ,  105 . The attachment device  110  may also be connected to a step  104  of the ladder  100 .  
      The ladder  100  is also not limited as to the number and locations of attachment devices  100 . For example, one attachment device  110  or multiple attachment devices  110   a ,  110   b  may be provided on the ladder  100 . If a single attachment device  110  is provided on the ladder  100 , the attachment device  110 , for example, may be located at an upper distal end of the ladder as shown in  FIGS. 4A, 4B . By positioning the attachment device  110  at the upper-most portion of the ladder  100 , a user connected to the attachment device  110  would always be positioned substantially at or below the position of the attachment device  110 , which decreases the distance the user would fall before the fall arrest system is activated.  
      If, for example, multiple attachment devices  110  are provided on the ladder, one attachment device  110  may be positioned at the upper-most portion of the ladder  100 , and a second attachment device  110  may be positioned substantially centrally along a longitudinal axis of the ladder, as shown in  FIGS. 3 and 5 A,  5 B. By positioning the attachment devices  110 , each attachment device  110  will cover substantially the same length of ladder  100 . Alternatively, the attachment devices  110  may be located on the ladder  100  at predetermined distances. For example, for a 15′ ladder and three attachment devices  110 , the attachment devices  110  may be located every 5′ along the ladder  100 . The predetermined distance the attachment devices  110  are located along the ladder  100  may also be determined by the type of fall arrest system used. For example, if the fall arrest system uses a lanyard, the predetermined distance may increase with longer lanyards and decrease with shorter lanyards.  
      As with other types of ladders, which may also advantageously utilize the hooks  120  disclosed herein, the ladder  100  is typically formed from aluminum, fiberglass, or pultruded or extruded resinous (e.g., thermosetting or thermoplastic) materials. In various aspects, the overall length of the ladder  100 , as measured by the ladder rails  102 ,  103 , is advantageously selected to be between 13′ and 22′, with 14′ and 16′ being preferred lengths and lengths of 18′ and 20′ also being desirable. The present ladder  100 , however, is not limited to a particular length.  
      As with conventional tapered posting ladders  10 , the upper portion of ladder  100  may be inwardly tapered (best shown in  FIG. 3 ). This tapering may occur at the upper  5 ′ feet of the ladder  100  length or at any other arbitrary point. The degree of the taper may be changed depending upon the starting point of the inward taper along the length of the ladder  100  to provide a ladder step of suitable width at the upper extents of the ladder  100 . Additionally, an outward taper may be provided at a bottom portion of the ladder  100 . Again, the outward taper may occur at the lower  5 ′ feet of the ladder length, or at any other arbitrary point, with the degree of the taper selected so as to provide a manageable ladder width and to ensure stability of the base of the ladder  100 .  
      The embodiments described herein can be practiced by employing conventional materials, methodology and equipment. Accordingly, the details of such materials, equipment and methodology are not set forth herein in detail. In the previous descriptions, numerous specific details of one preferred example, such as specific materials, structures, etc., are set forth to provide a grounding in the present invention. However, it should be recognized that the present invention can be practiced without resorting to the details specifically set forth. In other instances, well known processing structures have not been described in detail, in order not to unnecessarily obscure the present invention. It is to be understood that the present invention is capable of use in various other combinations and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein.