Abstract:
A fall restraint device for attachment to an extendable or telescoping ladder platform has a safety rope for attaching a slidable lanyard fixed to a climber. The length of the rope lies on tops of the exposed rungs of the ladder and extends with the ladder as the ladder is deployed and wherein upon retraction of the ladder the rope follows the ladder and toward the base or turntable of the ladder. The lanyard for attachment to a climber of the ladder and for slidable attachment to the safety rope has a locking element at the slidable attachment to the rope. The locking element slides freely unloaded, but locks the lanyard to the safety rope when under load of a falling or slipping climber.

Description:
RELATED APPLICATIONS 
       [0001]    The present invention claims benefit of priority to U.S. Provisional Application 61/683,316 entitled “Aerial Ladder Safety Device” filed on Aug. 15, 2012. 
     
    
     TECHNICAL FIELD 
       [0002]    This invention relates to a fall restraint device for attachment to vertically extendible platforms mounted on vehicles, such as an aerial ladder mounted on a fire truck. More particularly, the invention relates to an arrangement for preserving safety in the operation of an aerial ladder or the like while permitting its use while securing a climbing firefighter. 
       BACKGROUND OF THE INVENTION 
       [0003]    Many safety and maintenance vehicles are equipped with vertically extendible devices to permit operation high above the ground. An example is an aerial ladder carried by a fire truck. These vertically extendible devices must be carefully supported and stabilized for the safety of persons using them. An aerial ladder on a fire truck, for example, is typically mounted on a rotatable base or platform which permits the ladder to be positioned at any point on a circular arc. The fire truck and ladder are stabilized by outriggers deployed outwardly on opposite sides of the truck. Such outriggers usually extend about five feet on each side of the fire truck and provide very good stabilization for any rotational position of the aerial ladder. 
         [0004]    The platforms or aerial ladders typically are refracted in stacked sections onto a fire truck such that the length can be reduced while driving. The ladder can have three or more stacked sections that are laid on top of the others. As the ladder is set up vertically, these sections are driven upwardly extending the ladder. When fully extended the ladder can reach 75 to 150 feet or more. The incline of the ladder typically is 60 degrees or more, often almost vertically oriented up to 75 degrees or so. The ladders have rungs onto which the firefighter places his or her feet to upwardly climb. The sides have handrails to help keep the firefighter from falling. 
         [0005]    Often the firefighter is laden with heavy equipment while climbing and has much of this weight on his or her back. This magnifies the risk of losing balance and slipping. Once the start of a fall occurs, if the firefighter cannot catch oneself by grasping a rung or handrail, he or she is likely to fall. Too often this fall is fatal due to the extreme heights. 
         [0006]    To prevent falling, the firefighter can tie himself or herself to the top of the extended ladder once he or she has climbed that far. Unfortunately, the falls often occur as the firefighter is climbing and to date there has been no way to safely secure the climbing firefighter without impeding his or her rapid ascent. 
         [0007]    It is therefore an object of the present invention to provide a safe and simple fall restraint device for use on such aerial ladders that secures the climbing firefighter while not interfering significantly with the climb while allowing safe maneuvering up and down the ladder. 
         [0008]    Another objective is to have the device employable with the extension of the ladder. 
         [0009]    Another objective is to have the device not interfere with the setting up, extension or refraction of the ladder, but rather to coexist with the ladder and the climber without detrimentally getting in the way of or impeding the operation. 
         [0010]    These and other objectives are achieved by the inventive fall restraint device described as follows. 
       SUMMARY OF THE INVENTION 
       [0011]    A fall restraint device for attachment to an extendable or telescoping ladder platform has a safety rope for attaching a slidable lanyard fixed to a climber. The device has a safety rope, having a first end for attachment to an anchor point on a side of the ladder at an end or top of the ladder and a second end located at or near the base of the ladder held on the same side as the first end. The length of the rope lies on tops of the exposed rungs of the ladder and extends with the ladder as the ladder is deployed and wherein upon retraction of the ladder, the weight of the rope follows the ladder and drops toward the base or turntable of the ladder wherein the rope piles at the base of the ladder and is unsecured from the ladder at the first end and placed in a rope bag or storage container after use. 
         [0012]    The second or bottom end of said rope is held taut or otherwise affixed at or near the bottom or base of the extended ladder. In an alternative embodiment, the second or bottom end of the rope is affixed to a windable spool. The spool can be manually wound having a wind up reel for manual winding of the rope back onto the spool. The spool can further include a spring loaded retractable rope spool. The spring tension provides continuous tension or tautness on the rope. Alternatively, the spool can have a spring loaded retractor reel for automatically winding the rope. Preferably, the spool is removably attached to the bottom of the ladder. This allows the spool with the wound rope to be detached from the ladder for stowing. 
         [0013]    The fall restraint device further has a lanyard for attachment to a climber of the ladder and for slidable attachment to the safety rope. The lanyard has a locking element at the slidable attachment to the rope. The locking element slides freely unloaded, but locks the lanyard to the safety rope when under load of a falling or slipping climber. The locking element can be a PRUSIK device. The PRUSIK device is a PRUSIK knot in the lanyard. Preferably, the PRUSIK knot is triple wrapped. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The invention will be described by way of example and with reference to the accompanying drawings in which: 
           [0015]      FIG. 1  is a view of an aerial or platform ladder vehicle with the ladder in a stowed transportable condition. 
           [0016]      FIG. 2  is a view of the aerial or platform ladder vehicle with the vehicle shown stabilized with outriggers and the ladder fully extended. 
           [0017]      FIG. 3  is a top view of the horizontally stowed ladder showing the fall restraint safety rope attached to an end of the ladder and lying above or on the outer exposed rungs. 
           [0018]      FIGS. 4   a,    4   b  and  4   c  show the ladder inclined vertically as the sections are extended, 
           [0019]      FIG. 4   a  shows the first section upright,  FIG. 4   b  shows the first and second sections extended, 
           [0020]      FIG. 4   c  shows the first, second and third sections extended. 
           [0021]      FIG. 5  is an enlarged partial view showing the safety rope having a clasped end fixed to the top end of the ladder. 
           [0022]      FIGS. 6   a,    6   b  and  6   c  show the retraction sequence of the ladder with the safety rope affixed showing the rope piling at the base of the ladder. 
           [0023]      FIG. 7  is a view of a lanyard harness for attachment to the safety rope and the ladder climber. 
           [0024]      FIG. 7   a  shows the climber of the ladder secured to the safety rope by the lanyard. 
           [0025]      FIG. 8  is an enlarged view of the lanyard locking element. 
           [0026]      FIG. 8   a  is a climber shown suspended by the ladder after falling. 
           [0027]      FIG. 9  is a view showing a manual spool with the safety rope for affixing to the base of the ladder. 
           [0028]      FIG. 10   a  shows the safety rope wound separately stowed in a bag when removed from the ladder ready for storing. 
           [0029]      FIG. 10   b  is a view showing the spool with an automatic retractor feature for mounting to a ladder frame or base. 
           [0030]      FIG. 11  shows the ladder with a spool mounted to the base. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]    With reference to  FIG. 1  an aerial or platform ladder vehicle  2  is shown with the ladder  4  in the stowed or transportable condition. The vehicle  2  has the platform ladder  4  with three or more sections shown stacked on top of the vehicle  2  to which a platform  3  is attached at an end  7  of the ladder  4 . This stacked orientation of the ladder  4  enables the ladder  4  to shorten its length so that it can easily be transported to the site where the ladder  4  is needed. In the exemplary vehicle  2  of  FIG. 1 , the vehicle  2  is a fire truck having an aerial or platform ladder  4  that is used in the fighting of fires. 
         [0032]    With reference to  FIG. 2 , the aerial or platform ladder  4  vehicle  2  is shown with stabilized outriggers  9  to stabilize the vehicle  2  with the ladder  4  shown in the fully extended position. As shown when the sections of the ladder  4  are extended, the ladder  4  can reach vertical heights of 75 to 100 feet or more. As shown the ladder  4  has rungs  6  upon which a firefighter can climb up the ladder  4 . On each side of the ladder  4  are handrails  5  that help secure the climber and help him or her in the event of a fall. These side handrails  5  extend outwardly from the ladder  4  a sufficient distance such that they provide some protection for the climber. This protection assists the climber in the event that debris or other falling matter should hit the side of the ladder to protect the climber  1  in his vertical ascent. 
         [0033]    With reference to  FIG. 3 , a top view of a horizontally stowed platform ladder  4  is shown. In this view, a fall restraint safety rope  10  is shown attached to an end  7  of the ladder  4  and is lying above or on the outer exposed rungs  6  of the ladder  4  when the ladder  4  is in its refracted condition. 
         [0034]    With reference to  FIGS. 4A ,  4 B and  4 C, the ladder  4  is shown sequentially being extended. Initially, the ladder  4  is oriented vertically or almost vertically with all the sections stacked. As shown in  FIG. 5 , the rope  10  is attached using a carabiner  12  or other clasp mechanism to the top of the ladder  4  preferably along one of the handrail  5  sides or the other. The rope  10  lies on the exposed rungs  6  and has a sufficient amount of length L to allow the ladder  4  to extend as the first section extends outwardly, the second underlying section of the ladder  4  is exposed. The rope  10  has a sufficient supply of length L to extend with the ladder as it is being extended upwardly with the rope  10  attached to the top end  7  of the first section  4   a  of ladder  4 .  FIG. 4B  shows the second section  4   b  in the extended condition. After this section  4   b  is extended, the third section  4   c  extends upwardly and the rope  10  is shown extending from the top end  7  all the way to the base  8  of the ladder  4 . Preferably, the rope  10  is held in such a condition that in the fully upright position it is taut. The rope  10  is preferably held with some resistance between the top end  7  and the bottom or base  8  along the entire extension of the rope  10 . At this point, the safety rope  10  is in orientation to facilitate a climber  1 . To facilitate the climber  1 , the climber  1  will wear a lanyard  30  around his waist or harness belt  18  such that the lanyard  30  can be connected to the safety rope  10 . Preferably the connection of the lanyard  30  is done using a locking device  20  that is normally held in an open unlocked position such that it can move freely up and down the safety rope  10  as the climber climbs the ladder  4 . As the climber  1  approaches the extended vertical ladder  4 , he must attach his lanyard  30  about the safety rope  10  and secure it to his waist belt  18 , preferably with a clasp  17  as shown in  FIGS. 7A and 8A . Upon doing so, the climber  1  is now safely secured to the safety rope  10  and can climb the ladder  4  rapidly as he ascends to the top. Once the climber  1  is climbing, should he slip or fall in any fashion, the end  31  of the lanyard  30  with the locking device  20  attached to the safety rope  10  will stop his descent shown in  FIG. 8A . This stopping of a climber  1  from falling is provided by a locking element  20  attached to the end  31  of a lanyard  30 . 
         [0035]    As shown in  FIG. 7 , and more particularly,  FIG. 8 , an enlarged view of the lanyard  30  is shown wherein the locking element  20  is shown as a PRUSIK device  20 . A PRUSIK device  20  is a locking element  20  that is formed by a specific wrapping of the lanyard  30  about the safety rope  10  forming a knot  22  in the lanyard  30 . This PRUSIK knot  22  as shown is a triple wrap knot  22  which enables the lanyard  30  to slide freely up and down the rope  10 , however, in the event of a load being applied to the lanyard  30  such as in a fall condition, the PRUSIK knot  22  will collapse upon itself creating a locking resistance from further movement upon the rope  10 . This provides the needed safety feature that will protect a firefighter  1  climbing the ladder  4  in an event he should slip or fall whether climbing up or coming down the ladder  4 . This is extremely important because the firefighter  1 , who has now lost his balance going up or coming down the ladder  4  can fall, but be safely assured that the lanyard  30  and rope  10  will secure him and prevent further slipping as shown in  FIG. 8A . The firefighter  1  may fall approximately a foot or slightly more dependent on the length of the lanyard  30  attached to the ladder  4  prior to the locking element  20  activating. The locking element activates automatically upon a load or force being applied to the lanyard  30 . This enables the firefighter  1  to move freely up or down the ladder  4  without impeding his ascent or descent. His hands are free and he can safely climb the ladder  4  without any interference from the safety rope  10  device. 
         [0036]    Importantly, when the safety rope  10  is fixed to the top end  7  of the ladder  4  adjacent the platform  3 , it preferably should also be secured somewhere along the bottom of the ladder  4 . This can be done, as shown in  FIG. 8A , by a clamping of a bottom end  11  of the rope  10  such that it has a proper length to allow for the full extension of the ladder  4  and yet will remain tightly secured to the ladder  4 . This facilitates the climbing as the lanyard  30  slides on the rope  10  to enable the locking end knot  22  to freely move. When the ladder  4  is needed to be refracted as the climbers  1  are off the ladder  4 , it is important that the safety rope  10  follows the refraction of the ladder sections  4   a,    4   b  and  4   c  in such a way that the rope  10  does not get entangled in the ladder sections  4   a,    4   b  and  4   c.  To accomplish this, the weight of the rope  10  is sufficient that the rope will lie against the exposed outer rungs  6  of the ladder  4  as it is being refracted. As the safety rope  10  falls it piles at the base  8  of the ladder  4 . Once fully refracted, and the ladder  4  is ready to be loaded in the horizontal position, the firefighters  1  can detach the top end of the rope  10  at the carabiner  12  and at the bottom end  11  of the rope  10  and stow the entire safety rope  10  in a bag  13  for later storage, see  FIG. 10A . 
         [0037]    More preferably, as shown in  FIGS. 9 and 11 , at the base  8  of the ladder  4  it is preferable that the entire safety rope be placed upon a manual spool  40 . This manual spool  40  preferably has a winding wheel  42  that allows the rope  10  to be rewound onto the spool  40  as the ladder  4  is being retracted. Under normal conditions, the rope  10  will feed from the spool  40  as the ladder  4  extends upwardly. Preferably, the spool  40  has a spring tension mechanism that provides a sufficient tautness on the rope  10  such that when attached to the bottom of the ladder, as the ladder extends, the rope  10  remains taut through the extension of each of the sections  4   a,    4   b  and  4   c  until the rope  10  and ladder  4  reach full extension. In this way, the climber  1  is safely secured to the rope  10  which is affixed at one end  7  by the carabiner  12  at the top and at the lower end  11  by the spool  40  at the bottom or base  8 . As shown, the spool  40  preferably can be detached from the ladder  4  upon full retraction of the ladder  4  such that the spool  40  with the wound safety rope  10  upon it can be stowed in the vehicle  2 . 
         [0038]    In an alternative embodiment shown in  FIG. 10B , a spool  50  has an automatic refractor  51 . In this fashion, the rope  10  may be automatically wound back onto the spool  50 , and will feed automatically onto the spool reel as a spring loaded retractor  51  pulls on the rope  10  constantly as the ladder sections  4   a,    4   b  and  4   c  are being retracted. In this embodiment, the spool  50  preferably is also detachable from the base  8  of the ladder  4  for storage. 
         [0039]    As shown, it is believed important that the safety rope  10  be a static kernmantle rope preferably having a diameter of ½″/12.5 mm or greater and breaking strength of at least 9,000 lbs, a length of 75 to 150 feet or whatever length is needed for the full extension of the ladder  4 . Typically these ladders  4  extend 75 to 100 feet or more, sometimes 130 to 150 feet in length. It is preferred that the rope  10  be of sufficient length that it is able to accommodate whatever length of ladder  4  is required. As shown, the end of the rope  10  has a carabiner  12  or quick release mechanism  12  or other attachment clasp or fastener  12  attached so that the rope  10  can be attached to a top end  7  of the ladder  4  and be allowed to be affixed there. Once the ladder  4  is refracted, this attachment or fastener can be unfastened in order to stow the safety rope  10  and spool  40 ,  50  if used. 
         [0040]    Furthermore, as shown, the locking device  20  used on the lanyard  30  tying the climber  1  to the safety rope  10  and attached to the climber  1  through his waist belt  18  or other harness can be any locking mechanism  20  that allows free movement of the climber  1 , but will lock onto the rope  10  in the event he should fall and a force be applied to the lanyard  30  such that it triggers the locking element  20  to clamp or clinch onto the rope  10  preventing further sliding downwardly. 
         [0041]    Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described, which will be within the full intended scope of the invention as defined by the following appended claims.