A buckle for imparting a tensile force between an elongated flexible strap and a buckle hinge pin means, said buckle comprising:
- a main buckle member adapted to be coupled by said buckle hinge pin means for transferring force from said main buckle member in a direction normal to an axis of said buckle hinge pin means, said main buckle member being elongated along an axis of elongation from a plane orthogonal to said axis of said buckle hinge pin means, and defining first and second ends therein, said buckle hinge pin means being coupled to said first end of said main buckle member for rotation about said axis of said buckle hinge pin means, said main buckle member further defining elongated first and second load bearing portions, each of said elongated first and second load bearing portions extending parallel with said axis of said buckle hinge pin means fixed locations on said main buckle member lying between said first and second ends of said main buckle member, both said elongated first and second load bearing portions lying in a second plane generally transverse to said axis of elongation of said main buckle member, said main buckle member further defining an elongated third load bearing portion extending parallel with said axis of said buckle hinge pin means, and lying in a third plane which is generally transverse to said axis of elongation, said third plane being at a location lying between said second plane and said second end of said main buckle member, said main buckle member further including second hinge coupling means defining a second hinge axis parallel with said axis of said buckle hinge pin means, said second hinge axis lying between said second plane and said third plane;
- a cam member defining a first load bearing portion near a first end thereof and a second load bearing portion near a second end thereof, said cam member including second hinge coupling means lying between said first and second ends of said cam member, said second hinge coupling means being adapted for hinged coupling of said cam means to said second hinge coupling means of said main buckle member, for rotation of said cam member relative to said main buckle member between a closed position and an open position, whereby in said closed position said first load bearing portion of said cam member is juxtaposed with said second load bearing portion of said main buckle member and said second load bearing portion of said cam member is juxtaposed with said third load bearing portion of said main buckle member, and whereby in said open position of said cam member relative to said main buckle member said cam member is rotated so that said first bearing portion of said cam member is separated from said second bearing portion of said main buckle member by an amount greater than in said closed position, and in which said second bearing portion of said cam member is separated from said third bearing portion of said main buckle member by an amount greater than in said closed position, whereby a strap is adapted to extend past said buckle hinge pin means, partially around said second load bearing portion of said main buckle member, between said first bearing portion of said cam means and said second bearing portion of said main buckle member, and between said second bearing portion of said cam member and said third bearing portion of said main buckle member, is simultaneously pinched between said first bearing portion of said cam means and said second bearing portion of said main buckle member, and said second bearing portion of said cam member and said third bearing portion of said main buckle member, in said closed position of said cam member, in a manner such that tensile forces applied to said strap relative to said buckle tend to increase said pinch, thereby tending to grip said strap more firmly with increasing tensile forces, and whereby, in said open position of said cam member, said strap is substantially free to slip without being pinched past said first bearing portion of said cam means and said second bearing portion of said main buckle member, and said second bearing portion of said cam member and said third bearing portion of said main buckle member.