Patent Publication Number: US-6902031-B2

Title: Personal safety device for a vertical rope

Description:
FIELD OF THE INVENTION 
   The present invention relates generally to a safety device suitable for interconnection between a person and a substantially vertical rope. 
   BACKGROUND OF THE INVENTION 
   Various types of safety devices are known in the art. One type of device, known as a descender, allows a person to descend along a vertical rope at a selectively variable speed. Another type of device, known as a rope grab, is movably connected to a rope and locks in place in the event that a person falls. The present invention is directed toward a safety device capable of function as both a descender and a rope grab. 
   SUMMARY OF THE INVENTION 
   A preferred embodiment of the present invention may be described as a combination descender and rope grab device. The device includes a base, a handle pivotally mounted on the base, and a cleat pivotally mounted on the base. A rope is routed downward into the device and along a first bearing surface on the base, then horizontally between the cleat and a second bearing surface on the base, then downward between the cleat and a hub on the handle, then around the handle hub and between the handle hub and a third bearing surface on the base, then downward between the cleat and the handle hub again, and then downward out of the device. 
   When a user squeezes the handle toward the base, the rope is compressed between the hub and the third bearing surface on the base. When the handle is released and/or moved to a middle position, the device accommodates downward descent along the rope. When the speed of descent exceeds a threshold amount, the handle is urged further away from the base plate, and the rope is compressed between the cleat and the handle hub and between the cleat and the second bearing surface on the base plate, as well. 
   A torsion spring may be interconnected between the handle and the base to bias the handle toward a desired orientation relative to the base. Also, a cover plate is preferably pivotally mounted on the base and pivotal between a closed position, spanning the portion of the rope routed as described above, and an open position, allowing an intermediate portion of the rope to be routed as described above. Various features and/or advantages of the present invention will become apparent from the more detailed description set forth below. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     With reference to the Drawings, wherein like reference numerals designate like parts and assemblies throughout the several views, 
       FIG. 1  is a perspective view of a preferred embodiment safety device in an open configuration; 
       FIG. 2  is a side view of the safety device of  FIG. 1  with a cover removed to show the safety device in a first locked configuration relative to a rope; and 
       FIG. 3  is a side view of the safety device of  FIG. 1  with a cover removed to show the safety device in a second locked configuration relative to a rope. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   A preferred embodiment safety device constructed according to the principles of the present invention is designated as  100  in  FIGS. 1-4 . The device  100  generally includes a base  110 ; a handle  120  pivotally mounted on the base  110  (by bolt  121 ); a cleat  130  pivotally mounted on the base  110  (by bolt  131 ); and a cover  140  pivotally mounted on the base  110  (by bolt  141 ). 
   The base  110  may be described in terms of a middle portion and opposite side portions. The handle  120  is pivotally mounted on one of the side portions of the base  110 , and a hole  118  extends through the opposite side portion to receive a fastener, such as a carabiner or snap hook. The cleat  130  is pivotally mounted on the middle portion of the base  110 , proximate a lower end thereof, and a boss  119  is mounted on the middle portion proximate an upper end thereof. The boss  119  is configured to provide a first bearing surface which faces generally toward the opening  118 ; a second bearing surface which faces generally toward the cleat  130 ; and a third bearing surface which faces generally toward the handle  120 . Also, a hole  114  extends into the boss  119  to receive the bolt  141  for the cover  140 . 
   The handle  120  may be described in terms of a hub  122  and a lever arm  123 . The hub  122  may be described as a pulley or sheave having a perimeter which is three-fourths round and one-fourth flat. The hub  122  is eccentrically mounted on the bolt  121 , with a central portion of the flat side nearest the bolt  121 . The lever arm  123  extends away from the hub  122  in a direction generally parallel to the flat side of the hub  122 , and then in a generally perpendicular direction toward the middle portion of the base  110 . A distal portion of the lever arm  123  is rolled or folded to provide a comfortable, outwardly facing bearing surface. The lever arm  123  is pivotal to a position wherein a portion of the lever arm  123  parallels a portion of the boss  119  (as shown in FIGS.  2  and  4 ). 
   The cleat  130  may be described in terms of three portions which interface with the rope  99 . A first, flat portion faces generally toward the hub  122 ; a second, flat portion faces generally toward the boss  119 , and a third, rounded portion is disposed between the two flat portions. 
   The cover  140  may be described in terms similar to the base  110 . In particular, a middle portion of the cover  140  is pivotally connected to the base  110  (by bolt  141 ); one side of the cover  140  is provided with a hook  142  sized and configured to fit about the shaft of the hub bolt  121  and to fit beneath the head of the hub bolt  121 ; and a hole  148  extends through an opposite side of the cover  140  and aligns with the hole in the base  110  when the hook  142  is engaged with hub bolt  121 . A fastener, such as a carabiner or snap hook may be inserted through the aligned holes  148  and  118  to lock the device  100  in a closed position. As shown in  FIG. 1 , the fastener may be removed to facilitate attachment to or removal from the rope  99 . 
   As shown in  FIGS. 2-3 , the rope  99  extends downward into the device  100 ; along the first bearing surface on the boss  199 ; horizontally between the cleat  130  and the second bearing surface on the boss  119 ; downward between the cleat  130  and a hub  122  on the handle  120 ; around the handle hub  122  and between the handle hub  122  and the third bearing surface on the boss  119 ; downward between the cleat  130  and the handle hub  122  again; and finally, downward out of the device  100 . 
     FIG. 2  shows the handle  120  in an extreme counter-clockwise orientation relative to the base  110 . The device  100  assumes this configuration and locks onto the rope  100  in response to excessively fast descent along the rope  99  and the absence of user applied force against the handle  120 . Under such circumstances, the opposing bearing surfaces on the hub  122  and the cleat  130  are encouraged to rotate in opposite directions and toward one another. The rope  99  is compressed or pinched between the hub  122  and the cleat  130  and between the cleat  130  and the second bearing surface on the boss  119 . 
     FIG. 3  shows the handle  120  in an extreme clockwise orientation relative to the base  110 . The device  100  assumes this configuration and locks onto the rope  100  in response to user applied force against the handle  120 . Under such circumstances, the bearing surface on the hub  122  is rotated toward the opposing bearing surface on the boss  119 . The rope  99  is compressed or pinched between the hub  122  and the boss  119 . 
   When the handle  120  occupies an intermediate orientation relative to the base  110 , the rope  99  is no longer compressed at any point, and thus, the device  110  is relatively free to move along the rope  99 . Among other things, a torsional spring may be interconnected between the handle  120  and the base  110  to bias the handle toward this intermediate orientation, or any other desired orientation, relative to the base  110 . 
   The present invention may also be described in terms of methods. For example, the present invention provides a method of securing a safety device relative to a rope, comprising the steps of: providing a base  110  with a bearing member  119 ; pivotally mounting a first member  130  on the base  110  in such a manner that the first member  130  and the bearing member  119  define a first gap therebetween (see  151  in FIG.  3 ); pivotally mounting a second member  120  on the base  110  in such a manner that the second member  120  and the first member  130  define a second gap therebetween (see  152  in FIG.  3 ), and the second member  120  and the bearing member  119  define a third gap therebetween (see  153  in FIG.  2 ); routing the rope  99  through the first gap  151 , then through the second gap  152 , then about the second member  120  and through the third gap  153 , then through the second gap  152  again. The first member  130  is preferably pivotally mounted in eccentric fashion on the base  110 , so the first gap  151  has a width that varies as a function of orientation of the first member  130  relative to the base  110 ; and the second member  120  is also preferably pivotally mounted in eccentric fashion on the base  110 , so the third gap  153  has a width that varies as a function of orientation of the second member  120  relative to the base  110 , and the second gap has a width that varies as a function of orientation of the first member relative to the base and/or orientation of the second member relative to the base. 
   The present invention has been described with reference to a preferred embodiment and a specific method. Recognizing that various alternatives, modifications, and/or applications are possible, and that this disclosure will enable persons skilled in the art to derive other embodiments and/or applications, the scope of the present invention is limited only to the extent of the claims that follow.