Abstract: A sheath for housing a retractable knife both in its retracted or unretracted state provided with a pair of pockets, one adapted to receive the knife blade and a second adapted to receive the knife when the blade is housed within its handle, and additionally capable of being folded into a more compact form when housing a retracted knife.

Abstract: A positive lock and quick release knife and sheath wherein an abutment extends from the sheath and through the knife and a spring normally urges the knife against the abutment to positively prevent movement of the knife relative to the sheath, and the front or outer wall of the sheath being shortened to facilitate quick release of the knife from the sheath when the spring is overcome and the knife is moved away from the abutment.

Abstract: A snap lock connector is provided for positively mechanically locking two articles together while enabling their immediate separation responsive to the push of a button. The device comprises a bifurcated locking member extending from a first article and normally urged outwardly into locking position within a chamber in a second article. A push-button surmounts the locking member and projects outwardly from the second article. When the push-button is depressed, it overcomes the spring tendency of the locking member and moves the bifurcated locking portion together enabling to be withdrawn from the second article, whereupon the second article may be separated from the first article. The invention is capable of many uses, including the locking of a knife in its sheath.

Abstract: A positive delivery sheath for a knife of the type having a handle and a blade housed within the handle when not in use, and a flexible strap connected at one end to the sheath and normally encircling the knife within the sheath to protect the knife against accidental removal, and the strap being extensible to positively deliver the knife from the sheath when desired.

Abstract: A concavely ground knife blade has a pair of side faces characterized by oppositely-directed, continuous, slightly concave surfaces. Such surfaces have an arcuate profile approximately fitting a large (e.g., 30 inch) radius circle and follow essentially straight line axes which gradually bend toward one another to form a point. The side faces are first ground widthwise along a diameter of a grinding wheel having an end face beveled at a shallow angle to form a frustoconical grinding surface. The side faces are then polished lengthwise. The resultant blade has a median thickness in its midportion which is nearer the back of the blade than the cutting edge.

Abstract: An adjustable balance knife handle is integrally formed of a handle material (e.g., aluminum) formed in two mirror-image halves. Each half has a plurality of cavities disposed along its inner surface. Selected cavities are filled with a weighting material (e.g., lead) to adjust the balance and heft of the knife. Any remaining cavities are filled with a lightweight filler material (e.g., plastic foam) to exclude water from the handle.

Abstract: A combination of a knife and scabbard is disclosed, the knife having a lateral projection on its handle and the scabbard having a stop on the inner surface of one side edge thereof for engaging the projection when the knife is inserted into the scabbard, preventing accidental release of the knife. A slot opening in the upper part of the scabbard opposite the stop can be widened by forcing the knife handle into it to disengage the projection from the stop, permitting the knife to be withdrawn from the scabbard. A strap and fastener releasably prevent widening of the slot opening to lock the knife in the scabbard.