Abstract:
A buckle includes a strap slidably looped around a strut proximate a front opening of a housing, a spring-biased, lever-like ratchet having front and rear sections and a front engagement tooth adapted to matingly engage with one of a plurality of rack teeth on an upper surface of the strap, and two opposite pivotal arms extending outside of the housing. Pressing the arms will push down the rear section to lift the front section to disengage the engagement tooth from the rack tooth, thereby adjusting the buckle in discrete increments to tighten the strap.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. A Field of Invention 
         [0002]    The invention relates to ratchet buckles and more particularly to such a ratchet buckle having a strap slidably looped around a strut proximate a front opening of a housing, a spring-biased, lever-like ratchet adapted to engage with one transverse tooth of a rack of teeth on an upper surface of the strap, and two opposite arms such that pressing the arms will adjust the buckle in discrete increments to tighten the strap. 
         [0003]    2. Description of Related Art 
         [0004]    Ratchet buckles are widely used for securing together two objects by cooperating with a strap. One advantageous benefit of the ratchet buckle is its tension adjustability Therefore, ratchet buckles can be found in many applications including masks, swim goggles, etc. 
         [0005]    One type of conventional ratchet buckle includes a housing having two opposite pivotal arms extending outside thereof the arm having a latched end, and a strap having a rack of teeth on its upper surface. An individual may press and pivot the arms to unfasten the strap prior to adjusting the tension of the strap. However the well known adjustable ratchet buckle is not precise in tension adjustment. Further, components are subject to damage after a short period of time of operation. Thus, it is desirable to provide a novel adjustable ratchet buckle in order to overcome the inadequacies of the prior art. 
       SUMMARY OF THE INVENTION 
       [0006]    It is therefore one object of the invention to provide an adjustable ratchet buckle comprising a strap slidably looped around a strut proximate a front opening of a housing, a spring-biased, lever-like ratchet having front and rear sections and a front engagement tooth adapted to lockingly engage with one tooth of a rack of teeth on an upper surface of the strap, and two opposite arms such that pressing the arms will lift the front section to disengage the engagement tooth from the rack tooth, thereby adjusting the buckle in discrete increments to tighten the strap. 
         [0007]    It is another object of the invention to provide an adjustable ratchet buckle having two opposite arms exposed at both sides of a housing, and a ratchet within the housing. Both the arms and the ratchet are durable and can be manipulated precisely, thereby effecting a precise tension adjustment of strap. 
         [0008]    The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view of a preferred embodiment of adjustable ratchet buckle according to the invention; 
           [0010]      FIG. 2  is an exploded view of the ratchet buckle; 
           [0011]      FIG. 3  is a sectional view taken along line A—A of  FIG. 1  where the engagement tooth and the rack teeth are engaged in a fastened position; 
           [0012]      FIG. 4  is a view similar to  FIG. 3  where the engagement tooth and the rack teeth are not engaged so as to adjust the strap tension; 
           [0013]      FIG. 5  is a sectional view taken along line B—B of  FIG. 1  where both arms are not activated in the fastened position; and 
           [0014]      FIG. 6  is a view similar to  FIG. 5  where both arms are pressed toward each other to elastically lower the rear section of the ratchet so as to disengage the engagement tooth from the rack teeth prior to tension adjustment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    Referring to  FIGS. 1 and 2 , an adjustable ratchet buckle in accordance with a preferred embodiment of the invention comprises a cover  10 , a base  20 , two arms  30 , a ratchet  40 , a spring  50 , and a strap  60 . Each component is discussed in detail below. 
         [0016]    A housing is composed of the cover  10  and the base  20 . The ratchet  40  is provided in the housing. A front opening  11  is formed in the cover  10  for permitting the strap  60  to insert thereinto. Two openings  12  are formed on opposite sides of the cover  10  for permitting the arms  30  to dispose therein. The rear end of the cover  10  is secured to an object such as mask, goggles, etc. 
         [0017]    The cover  10  is somewhat curve in shape. Two holes  13  are provided on both sides of the front opening  11 . A strut  61  is secured between the holes  13 . A first stub  14  is formed on the bottom of the top surface of the cover  10 . A plurality of through apertures  15  are formed in the cover  10 . 
         [0018]    The base  20  comprises a plate member  22 , two opposite ears  23  proximate both sides of the plate member  22 , the ear  23  having a through hole  23   a , two pins  24  besides the ears  23  for pivotably mounting the arms  30  thereon, and a plurality of front and rear projections  21 . 
         [0019]    The arm  30  comprises a toothed trigger  31  on an outer surface, a rear protrusion  33  on an inner surface, the protrusion  33  having an inclined bottom plane  33   a , and a front protuberance  32  on the inner surface, the protuberance  32  having a longitudinal hole  32   a  rotatably put on the pin  24 . Hence, the arms  30  are adapted to pivot about the pins  24 . The rear end of the trigger  31  will be stopped by the rear end of the side opening  12  when the arms  30  pivot outwardly (i.e., releasing the arms  30 ). Hence, the arms  30  are allowed to pivot in a limited angle as detailed later The ratchet  40  is somewhat curve at both ends. The ratchet  40  is provided in the housing consisting of the cover  10  and the base  20 . The ratchet  40  comprises two pins  41  in the midpoints of both sides, the pins  41  being rotatably inserted into the through holes  23   a  (i.e., the pins  41  being served as fulcrum), a front section  42 , an engagement tooth  44  on the front end of the front section  42 , the engagement tooth  44  having an inclined plane (or a curved plane in other embodiments)  44   a , a rear section  43  having two rounded top corners (or inclined planes in other embodiments)  43   a  on both sides, and a second stub  45  on the top of the engagement tooth  42  aligned with the first stub  14 . The spring  50  has both ends put on the stubs  14 ,  45 . That is, the spring  50  is biased between the ratchet  40  and the bottom of the top of the cover  10 . 
         [0020]    After mounting the ratchet  40  in the cover  10  by assembling with the base  20 , and mounting the arms  30  on the pins  24 , the projections  21  are matingly inserted into the through apertures  15  for assemble the cover  10  and the base  20  as a complete housing. Note that the fastening of the cover  10  and the base  20  may be implemented in a fashion different from the one described above. Hence, a lever-like ratchet  40  is mounted. Note that the engagement tooth  44  may be replaced by a detent member having the same function as the engagement tooth  44  as detailed later. 
         [0021]    Referring to  FIG. 3 , the strap  60  has a plurality of parallel rack teeth  62  on a portion of an upper surface, Referring to  FIGS. 3 to 6 , an operation of the invention will be described in detail below. In an inoperative position (see  FIGS. 3 and 5 ), the arms  30  are not pressed with the inclined bottom planes  33   a  of the protrusions  33  being disengaged from the rounded top corners  43   a  of the rear section  43 , the front section  42  being biased downward by the expanding spring  50 , and the engagement tooth  44  being lockingly engaged with one of the rack teeth  62  (i.e., the strap  60  being prevented from moving in a direction as indicated by arrow in  FIG. 3 ). Hence, the strap  60  is fastened. 
         [0022]    As shown in  FIGS. 4 and 6 , an individual may press the arms  30  toward each other to lower the inclined bottom planes  33   a  of the protrusions  33 . Hence, the rounded top corners  43   a  of the rear section  43  are pressed down by the inclined bottom planes  33   a  of the protrusions  33 . And in turn, the front section  42  pivots upward about the pins  41 . Also, the ratchet  44  moves upward. Hence, a gap between the ratchet  44  and the strut  61  increases to permit the strap  60  including its rack teeth  62  to freely pass (i.e., the strap  60  being unfastened for being ready to adjust its tension by pulling in a direction as indicated by the arrow shown in  FIG. 4 ). At the same time, the spring  50  is compressed to store elastic energy. 
         [0023]    The spring  50  will immediately release its stored energy to push the front section  42  downward after releasing the arms  30  after adjusting strap tension. As a result, the buckle returns to its inoperative position as shown in  FIGS. 3 and 5 . At this position, the strap  60  is lockingly engaged with the ratchet  40 . In other words, it is possible of adjusting the buckle in discrete increments to tighten the strap  60 . 
         [0024]    As shown in  FIGS. 3 and 4 , the rack teeth  62  are of triangular in cross-section (i.e., any tooth having an inclined plane and a flat shoulder abutting an immediately adjacent tooth) and the engagement tooth  44  is shaped to complement any one of the rack teeth  62 . A pulling of the strap  60  is thus made possible with the engagement tooth  44  being disengaged from one of the rack teeth  62  after pressing the arms  30  (see  FIG. 4 ). Hence, an adjustment of the tension of the strap  60  can be made in discrete increments in order to tighten the strap  50 . To the contrary, the engagement tooth  44  engages with one of the rack teeth  62  due to the lowering of the front section  42  after releasing the arms  30  after adjusting strap tension. As an end, the strap  60  is locked in this position. 
         [0025]    In brief, pressing the arms  30  will unfasten the strap  60  for adjusting strap tension. Releasing the arms  30  will fasten the strap  60  in its tightened, locked position. Moreover, the lever-like ratchet  40  makes the strap tension adjustment operation more precise and reliable. 
         [0026]    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.