Patent ID: 7571520

Claim:
A buckle for tightening or loosening two straps joined at the buckle, each strap being extended from either end piece of a mask and having a plurality of equally spaced transverse ratchet teeth formed on an inner surface, comprising: a base including a top column; a rectangular sliding plate including a central hole shaped to slidably put on the column, inclined front and rear ends each falling into a dip between two adjacent teeth in a locked position of the buckle, two inclined sides, and a resilient assembly secured on the sliding plate; and a cover including a top bridge, front and rear openings, two parallel side walls secured to the base and each having an opening, front and rear struts formed across the side walls with the strap being partially wrapped around each strut, and two L-shaped latches each formed at the opening of the side wall between the struts, and the latch including a projecting outer surface wherein an end of each latch is disposed inside the cover and engaged with either side of the sliding plate, and wherein a top of the resilient assembly is biased against an inner surface of the bridge, whereby putting the mask on an object and pressing the outer surfaces of the latches toward each other will lift the sliding plate along the column with the resilient assembly being compressed by biasing against the bridge, cause the front and rear ends to clear the dip between the teeth, and enable the straps to freely slide through the front and rear openings of the cover by pulling free ends of the straps in a first direction, and stopping the pulling by releasing the latches will cause the sliding plate to slide downward by an expansion of the resilient assembly, cause the front and rear ends to fall into the dip between the teeth, and lock the straps; and whereby pulling the free ends of the straps in a second direction opposite the first direction will loosen the buckle and enable a removal of the mask from the object.