Respirator
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a respirator. More particularly, this invention pertains to a respirator having a pair of air filter sets assembled at respective sides of the respirator to block dirty particles and to permit air to pass therethrough which provides clean and fresh air to the wearer. 
     2. Prior Art 
     Respirators of various types are sold in the market. The prior art respiration mouthpieces are generally formed having a filter fastened at a front end, or at respective sides thereof by means of elastic cord. Such prior art respirators are deficient in filtering out dirty particles and tend to shift from one side to the other causing the wearer discomfort. 
     In view of this, the inventor has developed the present respirator which obviates the above mentioned shortcomings. 
     SUMMARY OF THE INVENTION 
     It is the primary object of the present invention to provide a respirator which isolates dirty particles from the wearer&#39;s respiratory system and permits fresh air to flow into the respirator. 
     It is another object of the present invention to provide a respirator where replacement of filters is simple. 
     It is a further object of the present invention to provide a respirator where filter sets will not randomly shift their positions. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the respirator of the present invention showing an air filter set disengaged from the respirator; 
     FIG. 2 is an exploded view of the filter set of FIG. 1; 
     FIG. 3 is a perspective view of FIG. 1; 
     FIG. 4 is a perspective view similar to FIG. 3, partially sectioned; 
     FIG. 5 is a sectional view taken along line A--A of FIG. 4; 
     FIG. 6 is another sectional view taken along line B--B of FIG. 4; 
     FIG. 7 is a plan view of the air filter set of a second embodiment; and 
     FIG. 8 is a plan view of the air filter set of a third embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, in particular to FIGS. 1 and 3, a respirator 1 formed of appropriate plastic material is shown. Respirator 1 includes a respirator casing having a pair of rectangular apertures 11 having a pair of integrally formed rectangular frames 12, each of which has a groove 13 on the inner center portion, respectively, adapted to receive an air filter set 2 therein. 
     Each air filter set 2 includes an inner filter 21 and an outer filter 22. The inner filter 21, as shown in FIG. 2, is composed of a receiving frame 213 having a continuous peripheral wall integrally formed to one side of the receiving frame 213 and having formed a flange 212 thereon. Each receiving frame 213 has an inner filter wall member having a plurality of triangle blocks 216 defining the wall member. A longitudinal trough or opening 211 is formed at one side of the wall member which is adapted to expel air breathed out by a wearer for forcing the air external the respirator. The opening or trough 211 is located at an innermost position of the respiration 1 after assembly. A dust protective layer 214 is detachably attached to the receiving frame 213 by means of a cover 215 pressing the dust protective layer 214 against the receiving frame 213. The cover 215 has the same shape or contour as the receiving frame 213 but is smaller in size than the receiving frame 213 and includes a plurality of 25 longitudinally directed apertures 217 adapted for the triangular blocks to extend therein. The triangular blocks 216 extending from the apertures 217 are adapted to force some portions of the dust protective layer 214 to extend through and outwardly of the cover 215 for the purpose of blocking any dirty particles from entering the respiratory 1 and being inhaled by the wearer as shown in FIG. 6. 
     The outer filter 22 is identical to the inner filter 21 with one exception that a trough 221 which is formed at one side of the peripheral wall of the receiving frame 223 for fresh air to flow into the respirator 1 is located at the outmost position when assembled to the respirator 1. Thus, the outer filter 22 includes a flange 222 corresponding to flange 212 of the inner filter 21, a cover 225 with apertures 227 and a dust protective layer 224 corresponding to dust protective layer 214. 
     In order to assemble the filter set 2, a user inserts the inner and outer filters 21, 22 into the rectangular frames 12 with the receiving flanges 212, 222 inserted into the grooves 13, respectively as shown in FIG. 4. A passage 23 is formed in between the inner and the outer filters 21, 22, as shown in FIG. 5, which is adapted for air to flow along the passage. 
     While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. For example, the shape of the filters 21, 22 can be changed from a curve to a wave shape, as shown in FIG. 7 or to a square shape, as shown in FIG. 8.