Abstract:
A device for attaching a replacement hook or other fitting to the end of a hoist cable includes a main body with multiple cable-receiving slots formed in the lengthwise edges. An attachment point is formed on one end of the main body, and a switch-engaging member is attached to an opposing end of the main body. A cable is attached to the device by winding the cable around the main body and into the cable-receiving slots. When attached to a cable, the switch-engaging member is positioned to activate a cut-off switch of a hoist when the cable is fully retracted.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to cable fittings for use in airborne search and rescue operations. More particularly, this invention relates to a field cable splice adapted for use in helicopter rescue operations and to a method for attaching a connection fitting to a cable end while a helicopter is in flight.  
         BACKGROUND OF THE INVENTION  
         [0002]    Helicopters are used to great advantage in Search and Rescue (SAR) operations. By conducting SAR operations from the air, greater distances can be searched, and otherwise inaccessible areas reached. Once an accident victim, downed airman or other person in need of assistance is located, the helicopter can then be used to retrieve that person. In many instances, it is not possible or safe for the helicopter to land. For example, the person to be rescued may be in the water and sea conditions may be too rough for the helicopter to land, or the helicopter may simply not be configured for water landing. When the person being rescued is on land, the helicopter may be unable land because of rugged terrain, trees, hostile ground forces, or other reasons. In such cases, a hoist in the helicopter can be used to lower a rescue hook, a harness, a basket or other retrieval device at the end of a cable, and then lift the rescued person up into the helicopter.  
           [0003]    Typically, the hoist is located above a door or other ingress/egress point on the helicopter, and positioned so that the rescued person is at the same level with the door when the cable is completely taken up. So that the hoisting mechanism will not be jammed or damaged, it is necessary to shut off the hoist upon completion of the hoist operation, i.e., when the rescued person is at door level. An automatic limit switch or similar device is generally incorporated into the hoist for this purpose. A large plate, ball or other shape is typically located at the terminal end of the cable (i.e., just above the rescue hook or other mechanism for attachment to the person being rescued, or to the retrieval device). As the cable is hoisted up and the rescued person reaches the level of the helicopter door, the plate, ball or shape engages a contact on the hoist and trips the limit switch, thereby stopping the hoist.  
           [0004]    On occasion, a rescue cable may become frayed or otherwise damaged, and the rescue hook (or other connection fitting) becomes unattached from the cable end. If there are remaining rescue operations to be performed, it is important that a replacement hook (or other connection fitting) be quickly and safely attached to the cable. It is also important that the automatic shut-off mechanism for the hoist remain operational. To date, however, there are no known devices that permit quick and simple attachment of a replacement hook under field conditions, while maintaining the operability of an automatic hoist shut-off.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention addresses many of the problems of prior art devices described above. In particular, the present invention provides a device for attaching a replacement hook or other fitting to the end of a hoist cable, and includes an attached member for activating a switch. In one embodiment, the invention includes a main body that has a distal and a proximal end, with two lengthwise edges between the distal and proximal ends. The main body further has multiple cable-receiving slots formed in the lengthwise edges. Each slot extends from a slot entry located on an edge of the main body to a slot termination that is displaced from the slot entry toward an interior of the main body. Some of the cable-receiving slots having a termination that is closer to the proximal end and an entry that is closer to the distal end. An attachment point is formed on the distal end of the main body, and a switch-engaging member is attached to the proximal end of the main body. The switch-engaging member has an opening for receiving a cable. The opening is positioned to receive the cable from the termination of the cable-receiving slot closest to the proximal end.  
           [0006]    In other aspects of the invention, indicia can be included on one or more portions of the main body, and the indicia can provide instructions for attaching the invention to a cable end. In aspects of the invention, a retainer may be included on a cable-receiving slot and/or on the opening in the switch-engaging member. Still other aspects of the invention include a method for attaching a connection point to a helicopter rescue hoist during airborne rescue operations. These and other aspects of the invention will be readily apparent and fully understood from the following detailed description of the preferred embodiment, taken in connection with the appended drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a front view of a cable splice assembly according to one embodiment of the invention.  
         [0008]    [0008]FIG. 2 is a rear view of a cable splice assembly according to one embodiment of the invention.  
         [0009]    [0009]FIG. 3 is a top view of a cable splice assembly according to one embodiment of the invention.  
         [0010]    [0010]FIGS. 4A-4F are perspective views showing use of the cable splice assembly according of FIGS. 1-3 to attach a rescue hook to a bitter end of a cable. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0011]    [0011]FIG. 1 is a front view of a cable splice assembly  10  according to one embodiment of the invention. Splice assembly  10  includes a main body portion  12  that is generally planar in form. Formed on the distal (or rescue) end of the main body portion  12  is hole  14 . Also formed in main body portion  12  are a series of slots  16 ,  18 ,  20 ,  22  and  24 . Slots  16 - 24  are sized to accommodate a wire rope rescue cable, and are angled toward the proximal (or hoist) end of the main body portion  12 . In other words, the opening of each slot (located on an edge of the main body portion  12 ) is closer to the distal end, while the termination of each slot (located toward the interior of main body portion  12 ) is closer to the proximal end. Formed in the front face  26  of main body portion  12  is groove  28 . Groove  28  extends from the termination of slot  20 , diagonally across face  26 , and toward the hoist end of the splice assembly  10 . Formed near the terminations of slots  16 - 24  are scallop-shaped relief notches  30 ,  32 ,  34 ,  36  and  38 . Also formed at the interior end of slot  24  is slot extension  40  extending toward the hoist end of the splice assembly  10 . Various indicia (“1,” “START,” various arrows, etc.) may also be stamped, engraved, painted or otherwise formed on front face  26 . The function of such indicia is further described herein.  
         [0012]    Attached to the hoist end of main body portion  12  is limit switch-engaging plate  42 . As is more clearly shown in FIGS. 3-4F, switch-engaging plate  42  is also generally planar, and is attached so as to be generally perpendicular to main body portion  12 . In other embodiments, a different shape could be attached to the hoist end of main body portion  12  and configured to engage a hoist limit switch. As but one example, a hemispherical shape having a flat face and a round face could be attached to main body  12  at the flat face, with the round face configured to engage a limit switch.  
         [0013]    [0013]FIG. 2 is a rear view of splice assembly  10 . Scallop-shaped relief notches  44 ,  46 ,  48  and  50  are respectively formed in rear face  54  near the terminations of slots  16 ,  18 ,  20  and  22 . Formed at the termination of slot  24  (i.e., at the end of slot extension  40 ) and extending toward engaging plate  42  is a groove  52 . Various indicia (“2,” “4,” various arrows) are also formed on face rear  54  of main body portion  12 . One end of a flexible cable retainer  56  is fastened along the edge of main body  12  near the opening of slot  24 . Cable retainer  56  may be fastened to an edge of main body portion  12  with screws as shown, or in another convenient manner. Another end of cable retainer  56  extends into slot  24 .  
         [0014]    [0014]FIG. 3 is a top view of splice assembly  10 . Switch-engaging plate  42  is disk shaped and attached to a top edge of main body portion  12  with a pair of countersunk screws  58 . Switch-engaging plate  42  could alternatively be attached to main body  12  with other types of mechanical fasteners, by welding, or in another manner. An opening  60  extends inward from the outer perimeter of switch-engaging plate  42  and terminates near the center of switch-engaging plate  42 . A cable gate  62  is pivotally attached at pin  64  to a point on the mouth of opening  60 . Gate  62  is biased by a spring (not shown) to obstruct the entrance to opening  60  from the edge of switch-engaging plate  42 . Gate  62  is configured such that it is pushed open by a cable pushed into opening  60  past the edge of switch-engaging plate  42 , but such that it will prevent a cable from exiting the opening past the same edge.  
         [0015]    [0015]FIGS. 4A-4F show use of splice assembly  10  to attach a rescue hook  100  to the bitter end of a cable  102 . One example of a suitable rescue hook that can be used with the splice assembly of the invention is described in U.S. Pat. N 0 . 6,363,589, assigned to the assignee of the present invention, Other types of rescue hooks and connection fittings could also be used with the splice assembly of the invention. Rescue hook  100  is attached to splice assembly  10  with a shackle  104 . As shown in FIG. 4A, an operator first positions splice assembly  10  such that cable  102  is resting in groove  28 . Cable  102  is positioned with the bitter end  106  at the hoist end of splice assembly  10 , and with approximately  3  inches of cable overhanging beyond the hoist end of splice  10 . Instructions are placed on the front face  26  of main body  12  that guide the operator in placing the cable. Holding the cable in slot  28  with a thumb or finger, the operator then winds the cable  102  around an edge of main body portion  12  and into slot  20 . A “1” and “START” on the front face  26  inform the operator to wind the cable in this manner. As shown in FIG. 4B, the operator next winds the cable across rear face  54 , over the opposing edge of main body portion  12  and into slot  18 . An arrow pointing from slot  20  to slot  18  and/or a “2” may be placed on the rear face  54  to inform the operator to proceed in this manner. Next, as shown in FIG. 4C, the operator winds the cable back across front face  26 , over the first edge of main body portion  12 , and into slot  22 . An arrow pointing from slot  18  to slot  22  and/or a “3” may be placed on the front face  26  to further inform the operator to proceed in this manner.  
         [0016]    After winding the cable  102  around main body  12  through slot  22 , the operator next winds the cable  102  across rear face  54 , around the opposing edge of main body portion  12 , and into slot  16 , as shown in FIG. 4D. An arrow from slot  22  to slot  16  and/or a “4” near slot  16  further instruct the operator in this regard. Next, as shown in FIG. 4E, the operator winds the cable  102  from slot  16  back across front face  26  (over the portion of cable  102  lying in groove  28 ), around the first edge of main body portion  12 , and into slot  24 . An arrow pointing from slot  16  to slot  24  and/or a “5” near slot  24  provide instructions to the operator on this step of the procedure. Upon moving the cable  102  into slot  24  and past retainer  56 , retainer  56  prevents cable  102  from exiting slot  24  by moving past the edge of main body portion  12 . The end of retainer  56  inside of slot  24  is biased to a position that closes the entry into slot  24  from the edge of main body  12 . As cable  102  moves past retainer  56 , retainer  56  bends to allow passage of cable  102  into slot  24 , and then returns to a position closing slot  24 . Although a single strip of flexible metal (such as, e.g., stainless steel) is shown, other types of retainers could be utilized. For example, a gate similar to gate  62  could be placed near the entrance to slot  24 . As but one other possible example, a close-fitting plastic insert could be fitted at the entrance of slot  24 . Other components and/or mechanisms configured to allow passage of a cable into slot  24  from the edge of main body portion  12 , but to prevent exit past the same edge, could alternatively be used.  
         [0017]    [0017]FIG. 4F shows the final step in attachment. After passing into slot  24 , the cable  102  is pulled up into extension  40 . Cable  102  is then pulled into opening  60  of switch activating plate  42 , past gate  62 , and into position generally near the center of plate  42 . Cable  102  rests in groove  52  (extending from extension  40  to plate  42 ) and generally lies along the longitudinal centerline of the splice assembly  10 . Cable  102 , with attached splice assembly and hook  100 , can now be used in rescue operations. Friction between cable  102  and the main body  12  prevent cable  102  from pulling out of splice assembly  10 . Retainer  56  and gate  62  prevent cable  102  from unwinding from splice assembly  10 .  
         [0018]    In one preferred embodiment, main body portion  12  and switch activation disk  42  are machined from 6061-T6 aircraft grade aluminum. Other materials can be used, including but not limited to stainless steel. When sized for a 0.19 inch cable, slots  16 - 24  are nominally 0.26 inches wide and main body  12  is 0.5 inches thick.  
         [0019]    Although specific examples of carrying out the invention have been described, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques that fall within the spirit and scope of the invention as set forth in the appended claims. In addition to examples provided above, various other materials may be used and dimensions varied. The indicia shown on the front and rear faces of main body portion  12  are merely examples of possible instructions that could be placed on a splice assembly according to the invention. Other indicia could be provided in addition to, or as an alternative to, the information shown. These and other modifications are within the scope of the invention as defined by the attached claims.