1. Field of Invention
The invention relates to buckles and more particularly to an adjustable buckle for tightening or loosening two straps joined thereat, each strap being extended from either end piece of a mask (e.g., one used for swimming or diving, one worn by an athlete, or a safety mask).
2. Description of Related Art
A conventional mask (e.g., one used for swimming or diving, one worn by an athlete, or a safety mask) has one or two head straps. For a mask having a single strap, a strap tensioner is mounted at either end piece of the mask. For a mask having two straps each extended from either end piece of the mask, a buckle is generally disposed at a rear central portion of the brain when a person wears the mask. As comparing the buckle with the strap tensioners, the buckle is more advantageous because it is simple in construction and can simplify the mask component.
However, the construction of the well known buckle is complicated and its use is not unreliable. Thus, the need for improvement still exists.
It is therefore one object of the invention to provide 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.
In one aspect of the invention the resilient assembly comprises four resilient members arranged as four corners of a rectangle around the hole.
In another aspect of the invention the resilient assembly is a coil spring.
In a further aspect of the invention the end of each latch is shaped as a hook.
The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings.
Referring to
Both the mask 10 and the straps 30 are well known devices except that the strap 30 comprises a plurality of equally spaced transverse ratchet teeth 31 formed on an inner surface. Thus, a detailed description thereof is therefore deemed unnecessary.
The buckle 20 as the subject of the invention comprises a rigid rectangular base 21 having a slightly curved bottom and including an upright column 22 of I-section on a top. Preferably, a pad is formed under the base 21 so as to provide a wearer with a degree of comfort while wearing the buckle 20 on the head.
The buckle 20 further comprises a rectangular sliding plate 23 including a central hole 231 shaped to slidably put on the column 22 (i.e., the sliding plate 23 adapted to slide upward or downward along the column 22 in operation as detailed later), inclined front and rear ends 232 (i.e., having a pointed edge) each falling into a dip between two adjacent teeth 31 in a locked position of the buckle 20, two inclined sides 233 (i.e., having a pointed edge), and four resilient members 234 arranged at four corners of a rectangular flange (not numbered) around the hole 231.
The buckle 20 further comprises a cover 40 including two parallel side walls 241 secured to the top of the base 21, front and rear struts 242 formed across the side walls 241, the strap 30 being partially wrapped around each strut 242, and two L-shaped latches 243 each formed at an opening of the side wall 241 between the struts 242, the latch 243 including an outer projecting surface for ease of pushing operation as detailed later, and a hook end 246 disposed inside the cover 40 and engaged with the side 233. An inner surface of the cover 40 under a top bridge 245 thereof is biased by the resilient members 234.
An operation of tightening the buckle 20 of the invention after putting the buckle 20 on the head will be described in detailed below. First, a wearer may press the outer surfaces of the latches 243 toward each other to lift the sides 233 (i.e., the sliding plate 23) along the column 22 with the resilient members 234 being compressed by biasing against the underside of the bridge 245 for storing elastic energy therein as indicated from the position of
To the contrary, the wearer may pull the free ends of the straps 30 in a direction opposite to that indicated by arrows of
Referring to
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While the invention herein disclosed has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.