Abstract:
A descent control device to facilitate rapid descent and abseil (rappelling) maneuvers, including a body, a handle integrally affixed to the body to define a longitudinal axis for the device, an attachment lug disposed on the body, and a combination of through holes through the body through which a safety line is threadably inserted in a specific pattern, and shallow channels between the through holes, thereby giving rise to configurations that allow the safety line to payout freely through the descent device, to be locked in relation to the descent device, or to payout in a controlled pace, all configurations depending on the orientation of the longitudinal axis of the device to the anchored upper portion of the safety line.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/310,580 filed Mar. 18, 2016, which is incorporated in its entirety by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present relates most generally to a descent control device to facilitate rapid descent and abseil (rappelling) maneuvers, and more particularly to a descent control device for use in either recreational or emergency abseil use, and still more particularly to a descent device specifically adapted for emergency rapid escape from a dangerous environment encountered by emergency first responders, firefighters, and military or law enforcement personnel. 
       BACKGROUND DISCUSSION 
       [0003]    Emergency rescue personnel (principally firefighters, and military and law enforcement personnel) may encounter conditions requiring a very rapid egress from a building or other structure at height. When trapped in a structure above ground level and in urgent need of getting to ground, but when having no reasonable means to descend to ground level in a customary manner (stairs, elevators, and the like), it is desirable to have equipment that provides for a safe descent in a non-customary manner- 13  such as by jumping from a window. To be able to do so safely in urgent circumstances is an answer to prayer; to have those prayers answered in advance is the object of the present invention. 
         [0004]    In principle, all descent control devices (aka “descenders”) use friction in one or another manner to control the rate of descent when using a rope to lower equipment or people. Broadly, there are two categories of descenders, namely variable friction and fixed friction, and three types: (1) figure eights, a fixed friction device commonly used for short drops and use in bottom belays, but prone to put kinks and twists in rope; (2) racks, which are variable friction devices which resemble a miniature ladder, most useful for very long descents but significantly bulkier and heavier than figure eights and thus not well suited for emergency use by first responders; and (3) bobbins, almost universally associated with popularized by its French caving gear producer, Petzl. Bobbins are constant friction descenders using bollards over which rope is threaded in a sinuous pattern to create a friction angle of about 480° . Newer models may include a rope brake that can be actuated to apply stopping force friction during a descent. Belay plates and Munter hitches are also popular. There are basically three types of descent devices: 
         [0005]    Type 1—Hand Brake/Hand Control Descent: User must hold onto the rope with this device to brake and to control their decent. If not, they will fall to the ground. 
         [0006]    Type 2—Auto Brake/Hand Control Descent: User does not need to hold onto the device when exiting a window, the device will auto brake for them. When the device is manipulated in some fashion via a lever or motion, the rope will be free to move depending on the user controlling the rope release. 
         [0007]    Type 3—Auto Brake/Auto Control Descent: User does not need to hold onto device when exiting a window, the device will break for them. The device can be also set to descend at a set rate of speed, no need for the user to control the rope. 
         [0008]    The present invention (which bears the proprietary name of the “Core”) is a Type 2 Auto Brake/Hand Control Device. It is an auto braking descent device that brakes without any help from the user. The unique feature of the Core is that it does not use any moving parts to make the auto breaking work. The absence of moving parts prevents damage and operational failure in the presence of debris, dirt, sand, or other potential impediments are present, such as are commonly found in firefighter and military activities and environments. It is the first to use gravity alone—i.e., the user&#39;s weight and threading of the rope into the device—to accomplish the auto breaking. 
         [0009]    Auto Brake/Hand Control Devices are popular among firefighters because firefighters were heavy protective firefighter gloves and are often unable to feel and locate the free end of the rope during an emergency exit. This is because firefighter gloves are bulky and lack flexibility, and dramatically decrease tactile awareness. Also, the inability to see clearly through a safety facemask, such as those worn by firefighters, limits the ability the see and to easily find and use the free end of the rope. Time is short in emergency situations, and just getting an anchor established is the only action one can accomplish prior to making an emergency jump from a window or roof. The Core catches the firefighter (stops freefall) once out the window, and the firefighter can then locate the handle and control the descent. Once out of the hazardous environment, the firefighter can locate the free end of the rope and manipulate the Core to complete a descent. 
         [0010]    Military personnel encounter similar problems, particularly when lowering from a helicopter and under fire. The Core will not allow a user to fall to the ground if wounded and disabled, and the user can thus be flown to a safer location. Again, the absence of failure-prone moving parts allows for a higher degree of safety. In contrast, when using a Type 1 descent device, the user would simply fall to the ground. And Type 3 devices are simply large, costly, and have several failure-prone moving parts that jam with debris. 
         [0011]    Existing descenders work sufficiently well in most commercial and recreational applications. But for the emergency first responder, an extremely high quality descent control device is required. This is particularly true because when intended for use by firefighters, descent control devices must meet extremely stringent standards set by the National Fire Protection Association (“NFPA”). Specifically, the NFPA 1983 (amended 2012) Escape “E” standards for Descent Control Device Performance Requirements of 3 σ MBS of not less than 13.5 kN (3,034 lbf). Under a load test, the descent control device must not allow rope to slide through the device when locked off under a load of 300+lbs. However, when the user wishes for rope to be paid out, when rope is released for free payout, the payout must occur at less than 20 lbs of applied force. NFPA 1983 standards also require that ropes must have strength, static, and stretch characteristics that will not allow them to break under a tensile load of 3,000 lbs, and many descent control devices will actually cause rope failure under such tensile loads. 
         [0012]    The present invention is a descent control device that meets and exceeds all NFPA 1983 standards for descent control hardware. It is lightweight, simple to use, self-righting, absolutely reliable, and perfectly adapted for firefighters, rescuers, and military and law enforcement personnel. Importantly, the descender is exceedingly simple to use, intuitive in every respect, and as a critical safety component is configured to immediately lock upon release when under load. When not under load, rope properly threaded through the hole configuration easily pays out horizontally, when, for instance, a firefighter is mapping a path through a smoke-filled structure using a tethered safety line. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is an upper perspective view showing the descent control device of the present invention; 
           [0014]      FIG. 2  is a lower perspective view thereof; 
           [0015]      FIG. 3  is a top plan view thereof (showing the outer side of the descender body); 
           [0016]      FIG. 4  is a side view in elevation thereof; 
           [0017]      FIG. 5  is a bottom plan view thereof (showing the inner side of the descender body); 
           [0018]      FIG. 6  is a side view in elevation showing the inventive descent control device installed on a climbing rope with a lanyard attached on one end to the attachment ring of the descender and a carabiner on the other end for attachment to a climbing belt D-ring, the rope and descender shown here in a payout configuration; 
           [0019]      FIG. 7  is a perspective view of the underside (also user-facing side) of the descender showing the hole configuration; 
           [0020]      FIG. 8  is an upper perspective side views showing details of the rope wrapping/threading pattern used for controlled descents; 
           [0021]      FIG. 9  is a lower perspective view showing details of the same rope threading pattern as seen from the underside (user-facing side) of the device; and 
           [0022]      FIG. 10  shows the descender device in use in a braking configuration. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    The descent device (descender) of the present invention  10  includes a body  12  having an outer side  14  (which faces away from user when in use, meaning when bearing a load) and an inner side  16  (which faces a user when in use). The body further includes an upper (superior) side  18  (generally oriented in a superior position when in use), a lower (inferior) side  20  (generally oriented in an inferior position when in use), a left side  22 , and a right side  24 . 
         [0024]    Integrally affixed to and extending from an inner portion  26  of the upper side  18  of the body  12  is a handle (or bar)  28  for gripping by a user. A rope clearance space for creating a gap or clearance between a climbing rope and the handle when a load is suspended is created by the distance D from the upper edge  30  of the upper portion  32  of the body  12  to the outer side  34  of the handle. The inner side  36  of the handle may be flat and is generally coplanar with the surface  14   a  of the inner side  14  of the body  12 . 
         [0025]    The body next includes an attachment lug  40  integral with an outer portion of the lower side  20  of the body  12 . The upper surface  42  of the attachment lug may be coplanar with the outer surface  14   a  of the outer side  14  of the body  12 . The attachment lug  42  includes a slot or hole  44  for passing a rope or lanyard, which is then employed to couple the descender to a user&#39;s climbing harness or belt. 
         [0026]    The body next includes a set of through holes, each passing from the upper side to the lower side of the descender body with the respective axes of the holes each oriented generally normal to the inner and outer sides, and thus parallel to one another. The holes include a payout hole  50  having a diameter  52  and a central axis  54  located on the longitudinal axis  56  of the descender. Conjoined to an upper portion  58  of the payout hole is an anchor hole  60  having a diameter  62  smaller than that of the payout hole and a central axis  64  also located on the longitudinal axis of the descender. Looked at from the top and bottom plan views ( FIGS. 3 and 5  respectively), wherein the broken circumference of each of the payout and anchor hole in the descender body side can be seen, the conjunction or intersection of the payout hole and the anchor hole comprises roughly 90(+/−30 degrees) of arc of the payout hole and 150(+/−30) degrees of arc of the anchor hole. The central axis of the anchor hole is oriented parallel to the central axis  54  of the payout hole  50 . 
         [0027]    Surrounding the payout hole on the outer side  14  of the descender body  12  is a chamfered opening  66  that provides a surface for inducing a gentle bend in rope disposed through the payout hole. Similarly, the upper end of the anchor hole includes a chamfered opening  68  that terminates in an arcuate shelf  70  formed at a depth from the surface  14   a  of the outer side  14  of the descender body  12 , such that rope sized for use in the descender will bend proud across the shelf in relation to the surface  14   a  of the outer side  14 . These features are described in more detail below and may be appreciated by reference also to  FIGS. 8-10 . 
         [0028]    Right and left holes  80 ,  90 , respectively, are disposed through the descender body, each having a central axis  82 ,  92  normal to the longitudinal axis  56  of the body. Right and left holes each include a chamfered upper opening  84 ,  94  to induce gentle bends in rope. 
         [0029]    Right and left holes  80 ,  90 , have chamfered lower openings  86 ,  96 , at the outer side  16  of the descender body  12 . Disposed between each of the left and right holes and the anchor hole  60  on the inner side of the descender body are shallow channels  88 ,  98  to accept and constrain a rope segment bent proud between one or the other side holes and the anchor/payout hole. The shallow channels are, respectively, longitudinally aligned with a line  80   d,    90   d,  drawn between the center of the right and left holes  80   c,    90   c,  and the center of the anchor hole  60   c.  Payout hole  50  and anchor hole  60  each have chamfered outer openings,  100 ,  102 , respectively. 
         [0030]    Referring next at  FIG. 6 , the descender device is shown set up for use in a rappel/descent operation. In such use, an attachment lanyard (a loop of Kevlar strap)  110  is attached at one end to lug  40  using a cow (or Larks foot or Girth) hitch  112 . A carabiner  114  is attached to another end. A climbing belay/rappelling rope  120  is connected at an upper end  122  to an anchoring device  124 . The free end  126  is threaded through the through-holes in the descender body in a specific pattern, described below. The carabiner is attached to the user&#39;s climbing harness or belt at a tie in loop or D-ring. 
         [0031]    Referring now to  FIGS. 7-9 , there is shown the threading pattern for passing a safety line or rope through the through-holes that enables a user to selectively lock or pay out safety line in a controlled manner when executing a descent. Before attachment to an anchoring device, the rope upper (anchoring) end is passed from the inner side  16  of the descender body through either right or left hole  80  or  90  (either work equally well) to the outer side  14 . Using right hole  80  as the illustrative example, a segment of the free end of the rope is then pulled through the right hole to provide a sufficient length for free end  126 . The upper end is then inserted into left hole  90  and passed back from the outer side  14  through the left hole  90  to the inner side, and a length of rope is pulled until a bend  130  is brought into engagement with shelf  70 , such that the outer surface of the rope at bend  130  is proud as to the descender body upper side  14  (i.e., disposed above it). The anchor line, comprising the upper end of the anchoring portion of the rope  120 , is then passed through payout hole  50  and pulled until a second bend  140  is brought into engagement with channel  98  extending from left hole  90  to the payout hole  50 . The upper end is then tied to an anchor device  124 . 
         [0032]    When so configured, (see  FIGS. 6, 8, 10 ), when under a load, the safety line pays out controllably and increasingly freely when the user pulls the handle bar down into a generally horizontally orientation, and the safety line is brought into increasing alignment with the central axis of the payout hole  50 . When under a load, if handle  28  is not pulled downwardly by the user, the device will remain in a generally vertical orientation (vertical as to its longitudinal axis  56 ), and bend  130  is thereby automatically brought into contact with anchor line  120 , thus causing the device to automatically brake. The anchor hole  60  is sized very slightly smaller than the selected rope diameter, thus in this vertical orientation, the safety line is prevented from free pay out and maintains alinement of the anchor portion of the line onto bend  130 , allowing a slow pay out under anticipated loads (comprising typical body weight with gear) simply by pulling down on the handle. Then, if and as the user wishes to slow, he controls the angle of the handle and tips it up accordingly. If he then wishes to come to a complete stop in the descent, he/she simply allows the handle bar  28  to tip freely up, which is accomplished using the force of the load only. This brings the safety line fully into the anchor hole and further brings the anchor line  120  into engagement with bend  130  to prevent further rope pay out, automatically.