Abstract:
An anchoring device for use in a rock-crevice defined by a first rock wall and an opposing second rock wall. The anchoring device comprises an axle member having a longitudinal axis. A first cam is rotatable about the longitudinal axis of the axle member and contactable with the first rock wall with the first cam having a first side wall and a second side wall. A second cam is rotatable about the longitudinal axis of the axle member and contactable with the second rock wall with the second cam having a first side wall and a second side wall. The first side wall of the first cam is aligned with the first side wall of the second cam and the second side wall of the first cam is aligned with the second side wall of the second cam. Upon a first force being applied to the first cam by the first rock wall and a second force being applied to the second cam by the second rock wall in a direction generally toward the longitudinal axis, the axle member is free from any created moment.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to an anchoring device for use in rock crevices and the like during rock climbing activities and, more particularly, it relates to an anchoring device for use in rock crevices and the like which utilizes an overlapping dual cam supported on an axle thereby inhibiting any induced moment on the axle while supporting a climber during rock climbing activities. 
     2. Description of the Prior Art 
     When two or more climbers move over difficult or dangerous ground, it is highly advisable and common practice to utilize a rope to secure the climbers together and to anchor the rope in slidable manner to the face being climbed. Furthermore, it is prudent to obtain a firm anchor to which the rope can be suitably secured. 
     In the past, numerous devices have been devised to assist climbers in securing ropes to cracks or crevices in rock walls for the purpose of climbing safety. Such anchors can be natural, i.e. rock spikes, flakes, chockstones jammed in cracks, natural rock threads, and the like. With such anchors, a separate loop of rope or webbing is attached to the natural anchor and to which the climbing rope is slidably secured. As an alternative to natural anchors, artificial anchors can be utilized. Thus, artificial chockstones or nuts are known of a variety of shapes and sizes and which are inserted into cracks or holes in the face being climbed where they can be made to jam. Pitons, also known, are steel spike-like members of various shapes and sizes which can be hammered into cracks or crevices in the rock face. Yet again, it is known to provide bolts, a modified form of piton and which are designed to be hammered into drilled holes in solid rock. 
     So far as natural anchors are concerned, these have no inherent disadvantage so long as the rock of the face being climbed is firm and not smooth. However, at the start of a climb it is often apparent that there are an insufficient number of natural anchors existing over the whole face. Artificial chockstones provide an efficient anchor especially when placed in an uneven (ragged) crack, but placing the artificial chockstone in place tends to be somewhat difficult and/or time consuming, and even good placements can be dislodged by movement of the climbing rope. When all that is available, where an anchor is needed, is a smooth-sided, parallel-sided crack, placement of the chockstones is difficult both to make and to ensure it is secured. 
     Both pitons and bolts again provide extremely efficient anchors, but with pitons being made from steel they tend to be heavy and can be difficult to place. Also, removal of pitons can be extremely difficult and as they tend to scar the rock surface, many climbers are unwilling to use them. Similarly, bolts take an appreciable length of time to place and cause a permanent disfiguration of the rock face. Due to these problems, there is an unwillingness among the climbers to employ bolts, except as a last resort. 
     More recently, spring loaded camming devices are used incorporating multiple pivoting cams which are spring-biased toward an open position to allow placement of these devices securely into rock cracks and rock crevices of varying sizes. To position the camming devices, the climber simply pulls a trigger closing the cams until the cams fit within the rock crack or crevice. The climber then releases the trigger and the spring or springs expand forcing the cams against the rock surface. Once a load is placed on the camming device, the cams expand and secure the climber to the rock face. An induced static friction force between the camming device and the rock face counteracts the applied load. Because such devices can be subject to substantial loads in holding a falling climber, it is desirable to construct such anchors in a manner which provides the greatest possible structural integrity of the device. 
     Spring loaded camming devices revolutionized climbing by allowing climbers to protect parallel-sided cracks in a variety of sizes. Conventionally shaped pivoting cam devices utilizing offset cams are constructed such that if only two conventionally shaped cams were used, the reaction forces caused by the supported weight of the climber create a moment on the axle connecting the offset cams. If sufficient force is applied, the pivoting cam device will begin rotating and release its hold on the rock. Other pivoting cam devices are too large for many piton scars and rock crevices and are, therefore, either not usable in many situations or cause the climber to use only a portion of the device thereby creating an unstable, and potentially dangerous, situation. 
     Accordingly, there exists a need for an anchoring device for use in rock crevices and the like which sufficiently supports a climber during rock climbing activities. Additionally, a need exists for a an anchoring device for use in rock crevices and the like which inhibits the creation of an induced moment by the reaction forces from the supported weight of the climber. Furthermore, there exists a need for an anchoring device for use in rock crevices and the like during rock climbing activities which utilizes an overlapping dual cam supported on an axle thereby inhibiting any induced moment on the axle while supporting a climber during rock climbing activities. 
     SUMMARY 
     The present invention is an anchoring device for use in a rock crevice. The rock crevice is defined by a first rock wall and an opposing second rock wall. The anchoring device comprises an axle member having a longitudinal axis. A first cam is rotatable about the longitudinal axis of the axle member and contactable with the first rock wall with the first cam having a first side wall and a second side wall. A second cam is rotatable about the longitudinal axis of the axle member and contactable with the second rock wall with the second cam having a first side wall and a second side wall. The first side wall of the first cam is aligned with the first side wall of the second cam and the second side wall of the first cam is aligned with the second side wall of the second cam. Upon a first force being applied to the first cam by the first rock wall and a second force being applied to the second cam by the second rock wall in a direction generally toward the longitudinal axis, the axle member is free from any created moment. 
     The present invention additionally includes an anchoring system for releasably securing a climber to a rock face with the rock face having a rock crevice. The anchoring system comprises an axle member, a first cam member having a first supporting surface and a first contact surface with the first cam member rotatable about the axle member, and a second cam member having a second supporting surface and a second contact surface with the second cam member rotatable about the axle member. Upon a force being applied to the first supporting surface of the first cam member and the first supporting surface of the second cam member in a direction generally toward the axle member, the first cam member contacts the second contact surface of the second cam member and the second cam member contacts the first contact surface of the first cam member. 
     The present invention further includes a method for securing a climber to a rock face. The method comprises providing a first cam and a second cam, rotatably securing the first cam and the second cam to an axle member, aligning the first cam with the second cam, applying a force to the first cam and the second cam in a general direction toward the axle member, contacting the first cam with the second cam, and inhibiting any created moment on the axle member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view illustrating an anchoring device for use in rock crevices and the like during rock climbing activities, constructed in accordance with the present invention; 
     FIG. 2 is an elevational side view illustrating the anchoring device for use in rock crevices and the like during rock climbing activities of FIG. 1, constructed in accordance with the present invention; 
     FIG. 3 is a perspective view illustrating a cam member of the anchoring device for use in rock crevices and the like during rock climbing activities of FIG. 1, constructed in accordance with the present invention; 
     FIG. 4 is a perspective view illustrating a combined axle and shaft member of the anchoring device for use in rock crevices and the like during rock climbing activities of FIG. 1, constructed in accordance with the present invention; 
     FIG. 5 an elevational side view illustrating the combined axle and shaft member of the anchoring device for use in rock crevices and the like during rock climbing activities of FIG. 4, constructed in accordance with the present invention; 
     FIG. 6 is a perspective view illustrating a cable of the anchoring device for use in rock crevices and the like during rock climbing activities of FIG. 1, constructed in accordance with the present invention; 
     FIG. 7 is a perspective, view illustrating a trigger of the anchoring device for use in rock crevices and like during rock climbing activities of FIG. 1, constructed in accordance with the present invention; and 
     FIG. 8 is a top view illustrating the anchoring device for use in rock crevices and the like during rock climbing activities of FIG. 1, constructed in accordance with the present invention, with the anchoring device being releasably secured within the rock crevice. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As illustrated in FIGS. 1 and 2, the present invention is an anchoring device, indicated generally at  10 , for use in rock crevices and the like for supporting a climber during rock climbing activities (see FIG.  8 ). In the present application, each element of the anchoring device  10  of the present invention will be described first. 
     As illustrated in FIGS. 4 and 5, the anchoring device  10  of the present invention includes a combined axle and shaft member  12  for rotatably supporting a first cam member  14  and a second cam member  16  (as illustrated in FIG.  1 ). Preferably, the first cam member  14  is substantially identical to the second cam member  16 . 
     The combined axle and shaft member  12  is preferably constructed from a 17-4 PH stainless steel material. It is within the scope of the present invention, however, to construct the combined axle and shaft member  12  from a different material so long as the combined axle and shaft member  12  is capable of supporting a predetermined force, i.e., two thousand (2000 lbs.) pounds, greater than the weight of the climber or climbers. 
     The combined axle and shaft member  12  preferably has a length of approximately 0.87 inch and a diameter of approximately 0.25 inch. It should be noted, however, that a combined axle and shaft member  12  having a length greater than or less than 0.87 inch and a diameter greater than or less than 0.25 inch is within the scope of the present invention. 
     Furthermore, the combined axle and shaft member  12  of the anchoring device  10  of the present invention includes a shaft portion  13 , a first axle portion  21  connected to the shaft portion  13 , and a second axle portion  23  connected to the shaft portion  13  substantially opposite the first axle portion  21 . Preferably, the first axle portion  21  has a length greater than the length of the second axle portion  23 . Both the first axle portion  21  and the second axle portion  23  have a groove  18  having a depth of approximately 0.031 inch. Once again, it should be noted that grooves  18  having a depth of greater than and less than approximately 0.036 inch is within the scope of the present invention. 
     Preferably, the combined axle and shaft member  12  is constructed from a PH stainless steel material to inhibit corrosion, although constructing the combined axle and shaft member  12  from other materials including, but not limited to, other types of steel material, ceramic, plastic, etc., is within the scope of the present invention. 
     As illustrated in FIG. 8, and as briefly mentioned above, the anchoring device  10  of the present invention additionally includes the first cam member  14  and the second cam member  16  which redirects force and applies the force to the rock face within the rock crevice. Preferably, the first cam member  14  and the second cam member  16  are identical in size and shape and are constructed from 7075-T6 aluminum providing high strength, durability, corrosion resistance, and ease of manufacture. Other materials for constructing the first cam member  14  and the second cam member  16  are within the scope of the present invention. 
     As illustrated in FIG. 3, both the first cam member  14  and the second cam member  16  have a first side  15 , a second side  17  substantially opposite the first side  15 , a curved supporting surface  22  between the first side  15  and the second side  17 , a substantially planar bottom surface  24 , a curved bearing surface  26 , and a substantially planar contact surface  28 . The supporting surface  22  of each cam member  14 ,  16  is preferably a logarithmic spiral shape which engages the rock surfaces of the rock crevice and crack. The logarithmic spiral shape of the supporting surface  22  allows the angle between the line of force and the rock face to remain the same regardless of which portion of the supporting surface  22  is contacting the rock face. Therefore, the force diagram for the anchoring device  10  will always yield the same results. 
     The first cam member  14  and the second cam member  16  of the anchoring device  10  further include a flange  30  extending from the curved bearing surface  26  in a general direction substantially opposite the supporting surface  22 . Each flange  30  has an axle-receiving aperture  32  formed therethrough for slidably receiving either the first axle portion  21  or the second axle portion  23  of the combined axle and shaft member  12 . 
     As illustrated in FIGS. 1 and 2, the first cam member  14  and the second cam member  16  are positioned about the combined axle and shaft member  12  by inserting the first axle portion  21  into the axle-receiving aperture  32  of the flange  30  of the first cam member  14  and the second axle portion  23  into the axle-receiving aperture  32  of the flange  30  of the second cam member  16  such that the first side  15  of the first cam member  14  is aligned with the first side  15  of the second cam member  16 , the second side  17  of the first cam member  14  is aligned with the second side  17  of the second cam member  16 , and the supporting surface  22  of the first cam member  14  is facing in an opposing direction as the supporting surface  22  of the second cam member  16 . At least one clip  34  or other attachment means are then positioned within each groove  18  of the combined axle and shaft member  12  for releasably maintaining the first cam member  14  and second cam member  16  in aligned rotatable fashion about the combined axle and shaft member  12 . 
     A torsion spring  36  is mounted about the first axle portion of the combined axle and shaft member  12  and attached to the first cam member  14  and the second cam member  16  to bias the first cam member  14  and the second cam member  16  together. Preferably, a first end of the spring  36  is inserted into aperture  37  of the first cam member  14  and a second end of the spring  36  is inserted into aperture  39  of the second cam member  16  or by screws  38 . The torsion spring  36  biases the first cam member  14  and the second cam member  16  in a general direction toward each other until the contact surface  28  of the first cam member  14  contacts the contact surface  28  of the second cam member  16 . The torsion spring  36  maintains tension on the first cam member  14  and the second cam member  16  such that the anchoring device  10  remains stationary subsequent to placement within the rock crack or crevice. While the inventors of the anchoring device  10  of the present invention have determined that a spring  36  having a spring constant of 0.173 in-lb./rad is sufficient for maintaining the appropriate tension between the first cam member  14  and the second cam member  16 , other spring constants are within the scope of the present invention depending on the size of the first cam member  14  and the second cam member  16 . Actual operation of the first cam member  14  and the second cam member  16  together with the entire anchoring device  10  will be described in further detail below. 
     Referring now to FIG. 5, the combined axle and shaft member  12  includes an cable-receiving aperture  48  is formed in the shaft portion of the combined axle and shaft member for receiving a cable  52 . The diameter of the cable-receiving aperture  48  is sized and shaped for receiving and the securing the cable  52  therein. 
     The anchoring device  10  of the present invention additionally includes the cable  52  having a first cable end  54  and a second cable end  56 . The first cable end  54  of the cable  52  extends into the cable-receiving aperture  48  of the combined axle and shaft member  12  and secured therein. The second end  56  of the cable  52  is looped around and swaged to itself to create a loop  58 . The loop  58  allows the climber to easily attach a carabiner (not shown) or the like to the anchoring device  10 . 
     Preferably, the cable  52  is a type  304 , stainless steel, 1×7 cable with a {fraction (1/8 )} inch diameter to support 2,100 pounds. Other types of cables  52  for use with the anchoring device  10  of the present invention are within the scope of the present invention. A sheath  59  can be positioned about the cable  52  for protecting the cable  52  from wear and damage during climbing activities. 
     The anchoring device  10  further still includes a trigger device  60 . A cable-receiving aperture  66  is formed in the substantial center of the trigger device  60  for receiving the cable  52  and to slidably position the trigger device  60  along the cable  52 . The trigger device  60  preferably has a substantially rectangular cross-sectional configuration and is constructed from an aluminum material. 
     A first wire  68  extends from the trigger device  60  and connects to a first wire-receiving aperture  72  in the first cam member  14 . A second wire  74  extends from the trigger device  60  and connects to a second wire-receiving aperture  78  of the second cam member  16 . Preferably, the first wire  70  and the second wire  76  are constructed from a stainless steel material, although other types of materials are within the scope of the present invention. 
     The operation of the anchor device  10  of the present invention will now be described. A person skilled in the art will understand that the anchor device  10  can be operated in numerous manners and that the description set forth below is merely one manner of operation. 
     As a climber climbs a rock face, the climber positions the anchoring device  10  into a rock crevice or crack formed in a rock face. First, the climber opens the first cam member  14  and the second cam member  16  by urging the trigger device  60  in a direction generally away from the first cam member  14  and the second cam member  16 . The action of the trigger device  60  overcomes the bias of the torsion spring  36  and causes the bottom surface  24  of the first cam member  14  and the bottom surface  24  of the second cam member  16  to move toward each other. A cable-receiving groove  80  can be formed in the bottom surface for receiving the cable  52  when the anchoring device  10  is in the retracted position. 
     The first cam member  14  and the second cam member  16  are then positioned within the rock crevice or crack formed in the rock face with the spring  36  facing toward the climber. With the spring  36  being positioned about the first axle portion of the combined axle and shaft member  12 , the climber can insert the anchoring device  10  further into the rock crack or crevice. The climber then releases the trigger device  60  causing the torsion spring  36  to bias the supporting surface  22  of the first cam member  14  and the supporting surface  22  of the second cam member  16  against opposed rock surfaces within the rock crevice or crack. 
     When a load is applied to the anchoring device  10 , the reaction force on the first cam member  14  and the second cam member  16  causes the flange  30  of the first cam member  14  to contact the curved bearing surface  26  of the second cam member  16  and the flange  30  of the second cam member  16  to contact the curved bearing surface  26  of the first cam member  14 . Since the first cam member  14  and the second cam member  16  rotate about the axle member  12  in the same plane, the anchoring device  10  of the present invention allows the first cam member  14  and the second cam member  16  to rotate and remain at equilibrium thereby inhibiting any induced moment on the axle member  12 . 
     While the anchoring device  10  of the present invention has been described as having one set of cam members, namely a first cam member  14  and a second cam member  16 , it is within the scope of the present invention to have multiple sets of cam members with each set of cam members including two cam members. 
     The anchoring device  10  of the present invention offers numerous advantages over conventional rock climbing devices. The anchoring device  10  is easily manufactured with identical first cam member  14  and second cam member  16 . The anchoring device  10  is significantly narrower in width than conventional devices with the same or more camming or supporting surface  22 . The anchoring device  10  can withstand the same applied force as conventional devices with the addition of the flexible cable  52  that allows the anchoring device  10  to bend over the rock, when necessary. 
     The foregoing exemplary descriptions and the illustrative preferred embodiments of the present invention have been explained in the drawings and described in detail, with varying modifications and alternative embodiments being taught. While the invention has been so shown, described and illustrated, it should be understood by those skilled in the art that equivalent changes in form and detail may be made therein without departing from the true spirit and scope of the invention, and that the scope of the present invention is to be limited only to the claims except as precluded by the prior art. Moreover, the invention as disclosed herein, may be suitably practiced in the absence of the specific elements which are disclosed herein.