Releasable lock

A releasable lock for securing together two parts of a wearable device comprising first and second parts, aligned through passages in said parts for receiving a locking pin, a pin in said passages maintaining said parts in coupled relation, one of said parts being equipped with an exterior surface, a bore in said one part communicating with said exterior surface and extending inwardly therefrom transversely to and communicating with the passage in said one part, said pin having a transverse bore alignable with said one part bore when said pin is maintaining said parts in coupled relation, and a ductile, elongated rivet mounted in said bores having inner and outer ends, the inner end of said rivet being the end first introduced into said bores, one of said pin and said one part being equipped with a counter bore receiving said rivet inner end and adapted to accommodate deformation of said rivet inner end resulting from force applied to said outer end, said rivet being more ductile than said pin whereby an axial force applied to said pin preferentially shears said rivet, said rivet prior to deformation having a length greater than the sum of the lengths of said bores whereby said rivet outer end, prior to inner end deformation, protrudes outwardly of said exterior surface.