Patent Publication Number: US-2012030912-A1

Title: Adjustable buckle for a respriator mask

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an adjustable buckle of the type that can be used with a respirator mask and specifically relates to adjustable buckle members that are integrally molded on a strap on a continuous basis. 
     Adjustable buckles are used as part of a respirator mask to allow the user of the mask to put the mask on and take the mask off in an easy fashion and to adjust the length of the strap for comfort. Part of the difficulty with prior art adjustable buckles is that they are somewhat cumbersome in structure and thereby expensive to manufacture. The present invention relates to an adjustable buckle that is simple in construction and easy to manufacture. 
     SUMMARY OF THE INVENTION 
     In the adjustable buckle of the present invention, the adjustable buckle is formed by two buckle members one of which has multiple elements molded around an elastic band and locked in position onto the elastic band using a novel method of manufacture described in prior U.S. Pat. No. 5,970,585. Specifically, if an adjustable buckle member is merely molded around an elastic band, when the molding process is over and the adjustable buckle member cools, the elastic band would slip within a molded channel formed in the molded adjustable buckle member. This is because the elastic material when stretched tends to reduce in size thereby allowing for slippage of the band inside the adjustable buckle member. 
     The prior invention overcomes this problem by pre-stretching the elastic band prior to the molding of the adjustable buckle members around the elastic band. The adjustable buckle members are actually molded around the elastic band in the stretched condition so that the elastic band within the channel in the molded member is actually stretched to a smaller size. When the molded adjustable buckle members cool, the band portion is already stretched and locked by friction in position within the channel. The stretched band wants to return to its unstretched state and this tends to increase the friction. Further pulling on the elastic band does not produce any significant further stretching of the band within the adjustable buckle members. The adjustable buckle member therefore is held tightly onto the elastic band by friction during use and the elastic band cannot slip out of the adjustable buckle. The present application is an improvement over the prior invention in providing for a simple means of adjustment of the length of the strap to which the buckles are attached by multiplying the number of buckle elements of one or both of the buckle members so that different length straps can be formed by interconnecting different buckle elements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a user of a respiratory mask and showing the adjustable buckles of the present invention at the back of the mask; 
         FIG. 2  is a detailed perspective view of two buckle members one of which includes multiple elements to form the adjustable buckle of the present invention; 
         FIG. 3  illustrates the buckle members one with multiple elements formed on an elastic band before the adjustable buckle members are separated; 
         FIG. 4  is a cross-sectional view taken along lines  4 - 4  of  FIG. 3 , and 
         FIG. 5  illustrates an alternate embodiment of adjustable buckle members of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As can be seen in  FIG. 1 , a user  10  of a respirator mask  12  is operating a piece of machinery. The respirator mask  12  includes a pair of adjustable buckles  14  located at the back of the mask. 
       FIG. 2  illustrates that the adjustable buckle  14  is composed of two component adjustable buckle members  16  and  18  each located at the end of a strap member  20 . The buckle member  16  is formed as a single member and the buckle member  18  is formed as three identical members. As shown in  FIG. 2  the adjustable buckle members  16  and  18  are molded around the strap  20  and form the end portions for the strap  20 . 
       FIGS. 3 and 4  illustrate the adjustable buckle  14  in top and cross-sectional views. As can be seen in  FIGS. 3 and 4 , the strap member  20  runs continuously through adjustable buckle members  16  and  18 . As explained in U.S. Pat. No. 5,970,585, the strap member  20  is parted to form the two separate adjustable buckle end members  16  and  18  shown in  FIG. 2 . As can also be seen in  FIGS. 3 and 4  the end portion of each adjustable buckle member  18  is formed as outwardly extending wing portions  22 . These wing portions  22  fit within the outwardly extending flange members  24  formed at the end of adjustable buckle member  16 . The adjustable buckle  14  is thereby engaged or disengaged easily by merely slipping the wing members  22  of any of the three buckles  18  to interlock with the flange members  24 . This can also be seen in the perspective view of  FIG. 2 . The length of the strap  20  can be adjusted in increments dependant on which on e of the three buckles is engaged with the flange  24 . 
       FIG. 3  also shows broken way portions  25  which illustrate that the strap  20  becomes narrower in a length of the strap  26  that is located within molded channels  27  in the adjustable buckle members  16  and  18  as described in U.S. Pat. No. 5,970,585. Similarly  FIG. 4  shows that the strap portion  26  is also thinner in the channels  27  which are contained within the adjustable buckle members  16  and  18 . The molded channels  27  are the result of stretching the strap member  20  to be narrower and thinner while the adjustable buckle members  16  and  18  are molded around the strap member. This insures that upon cooling the strap portion  26  will be locked within the molded channels  27  formed in the molded adjustable buckle members  16  and  18 . 
       FIG. 5  illustrates an alternate embodiment wherein the multiple buckles  18  are formed as one continuous member without the interconnecting strap portions of the continuous strap  20  as shown in  FIGS. 2 and 3 . The structure of  FIG. 5  is shorter and it would be possible to have a greater number of adjustments in the same length as  FIG. 3  by increasing the number of buckle members  18 . The structure of  FIG. 5  is stiffer and does not lie as comfortably against the back of the head. The structure of  FIGS. 2-4  is preferred for that reason. 
     It will be understood that any number of buckles members  18  may be used to increase the number of adjustments and the invention is not limited to three such members. The buckle member  16  may also be increased in number to provide for additional adjustments and both buckle members  16  and  18  may be multiples so as to further increase the range of adjustments. 
     Although the invention has been described with reference to a particular embodiment, it should be appreciated that various adaptations and modifications may be made and the invention is only to be limited by the appended claims.