Camming device for anchoring to rock protrusions

Abstract

A climbing aid having a rigid frame, two axles supported parallel to each other by the rigid frame, two pairs of cams pivotally mounted one pair per axle, and spring members mounted on the axles, which act to urge each cam into its extended position. The device clamps onto a rock protrusion such that the two pairs of cams are situated on the opposite sides of the protrusion. Initial force holding the device clamped comes from the spring members. Because of the shape of the cams, application of downward pull to the device translates into additional clamping forces applied to the rock protrusion. Application of pull onto a slidably mounted trigger actuates the cams into a retracted position, allowing the device to clamp onto protrusions of a range of sizes.

1 . A climbing aid that engages rock protrusions or other suitably shaped objects, said climbing aid comprising:
 (a) a fork-shaped rigid frame,   (b) two axles supported parallel to each other by said fork-shaped rigid frame, said axles located on the opposite sides of the trough of said fork-shaped rigid frame,   (c) at least one convex cam pivotally mounted on each said axle, said convex cams having their arcuate surfaces facing the trough of said fork-shaped rigid frame,   (d) means to urge said convex cams into extended position,   (e) a trigger,   (f) flexible means connecting said trigger to said convex cams, such that application of force to said trigger results in urging said convex cams towards retracted position.   
   
   
       2 . Invention of  claim 1 , wherein the convex cams have arcuate surfaces in the shape of logarithmic spiral. 
   
   
       3 . Invention of  claim 1 , wherein a flexible cable attached to the fork-shaped rigid frame is provided for attaching a climbing rope. 
   
   
       4 . Invention of  claim 3 , wherein the trigger is slidably mounted on the flexible cable.