Patent Publication Number: US-7913399-B2

Title: Blade set for hair clipper

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a blade set and more particularly pertains to a blade set for hair clipper which has a movable blade disposed between an upper fixed blade and a lower fixed blade and reciprocating laterally relative to the two fixed blades. 
     Blade sets for hair clippers available in the marketplace generally have a fixed blade and a movable blade. Lateral reciprocation of the movable blade relative to the fixed blade results in a cutting action. Since the movable blade is exposed to users during the cutting action, it is easy for users to get injured by the movable blade. 
     BRIEF SUMMARY OF THE INVENTION 
     In view of the aforesaid disadvantages now present in the prior art, the present invention provides a blade set for hair clipper which has one movable blade assembly disposed between an upper fixed blade and a lower fixed blade and reciprocating laterally relative to the two fixed blades. Since the movable blade assembly is covered by the two fixed blades, users are protected from getting injured by the moving blade assembly during the cutting action. 
     To attain this, the present invention generally comprises a lower fixed blade, an upper fixed blade, a movable blade assembly and a blade holder. The lower fixed blade is provided with a first toothed front edge. The upper fixed blade is provided with a second toothed front edge which is disposed on top of the lower fixed blade and aligned corresponding to the lower fixed blade so that the teeth of the first toothed front edge and the second toothed front edge do not overlap with each other. The movable blade assembly is disposed in between the lower fixed blade and the upper fixed blade and is connected to a driving means driven by a driving unit in the hair clipper to reciprocate laterally relative to the lower fixed blade and the upper fixed blade in an operating condition. A third toothed front edge is provided at a front end of the movable blade assembly. A lower portion of the third toothed front edge cooperates with an upper portion of the first toothed front edge to define a first cutting surface. An upper portion of third toothed front edge cooperates with a lower portion of the second toothed front edge to define a second cutting surface. The blade holder secures the lower fixed blade, the movable blade assembly and the upper fixed blade together to form a blade set and the blade set is connected to the hair clipper. 
     In one preferred embodiment, the movable blade assembly comprises one blade, and the blade is provided with a toothed front edge constituting the third toothed front edge. Each tooth of the toothed front edge of the movable blade assembly has a cross-sectional shape of a rectangle. 
     In another preferred embodiment, the movable blade assembly comprises a lower movable blade provided with a toothed front edge constituting the lower portion of the third toothed front edge, and an upper movable blade disposed fixedly on top of the lower movable blade and provided with a toothed front edge constituting the upper portion of the third toothed front edge, and the toothed front edge of the lower movable blade and the toothed front edge of the upper movable blade overlap with each other. Each tooth of the toothed front edge of the lower movable blade has a cross-sectional shape of an isosceles trapezoid, and each tooth of the toothed front edge of the upper movable blade has a cross-sectional shape of an inverted isosceles trapezoid. 
     In another preferred embodiment, each tooth of the first toothed edge of the lower fixed blade is integrally provided with a first protecting piece extending upward from a front end thereof, and each tooth of the second toothed edge of the upper fixed blade is integrally provided with a second protecting piece extending downward from a front end thereof. The thickness of the first and second protecting pieces is adapted to allow the movable blade assembly to reciprocate laterally. The first and second protecting pieces protect the user&#39;s hand from getting injured by the movable blade assembly. 
     The blade holder comprises a pressing piece and a base secured under the lower fixed blade and connected to the pressing piece, and the pressing piece presses against a top surface of the upper fixed blade. The base is provided with one or more pins which extend upward towards a lower surface of the pressing piece and pass through corresponding openings provided on each of the lower fixed blade, the movable blade assembly and the upper fixed blade, thereby securing the lower fixed blade, the movable blade assembly and the upper fixed blade in an assembled relation. The size of each opening of the movable blade assembly is larger than that of the corresponding pin so as to allow reciprocating actions of the movable blade assembly. 
     In one preferred embodiment, the base and the pressing piece are connected to each other by means of a torsion spring. The torsion spring comprises a coil member and two ends and is connected to the base via a rod. The rod passes through the coil member and is disposed at a rear end of the base. The two ends of the torsion spring are attached to the pressing piece, and the pressure exerted by the pressing piece against the upper fixed blade, the movable blade assembly and the lower fixed blade enables the three blades to be secured in an assembled relation. The rear end of the base is provided with two walls opposite to each other, one on the left side and one on the right side, and each wall is provided with a through hole in the middle for receiving one end of the rod. 
     In another preferred embodiment, a spring plate is disposed on top of the pressing piece to exert pressure against the pressing piece. A rear end of the base is provided with two nuts, one on the left side and one on the right side, for receiving two screws which pass through two corresponding holes on the spring plate. 
     The base is provided with a recess at its front end for receiving the lower fixed blade, and the shape of the recess corresponds to that of the lower fixed blade. 
     A guarding piece is disposed on top of each opening of the movable blade assembly for protecting the movable blade assembly from wear and tear during reciprocation. 
     The driving means is provided with one or more connecting pieces, and the movable blade assembly is provided with one or more notches corresponding to the connecting pieces for receiving the connecting pieces. 
     The connecting pieces pass through corresponding notches provided on each of the upper fixed blade, the movable blade assembly and the lower fixed blade, and the size of each notch of the upper fixed blade and the lower fixed blade is larger than that of the corresponding connecting piece so as to allow reciprocating action of the connecting piece. 
     The base is provided with one or more two protrusions, one on left side and one on right side, for connecting the blade set to the hair clipper. 
     It is an object of the present invention to provide a new blade set which allows safer hair cutting operation by placing the movable blade assembly in between the upper fixed blade and the lower fixed blade, thus overcoming the disadvantages of the prior art. 
     It is another object of the present invention to provide a new blade set which is of simple and reliable construction. 
     It is a further object of the present invention to provide a new blade set which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such blade set economically available to the buying public. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows the perspective view of the blade set of the first embodiment as connected to a hair clipper. 
         FIG. 2  shows the exploded view of the blade set of the first embodiment. 
         FIG. 3  shows the perspective view of the assembled blade set of the first embodiment. 
         FIG. 4  shows the enlarged view of the portion A of  FIG. 3 . 
         FIG. 5  shows the perspective view of the semi-assembled blade set of the first embodiment. 
         FIG. 6  shows the perspective view of the assembled blade set of the second embodiment. 
         FIG. 7  shows the enlarged view of the portion A of  FIG. 6 . 
         FIG. 8  shows the perspective view of the assembled blade set of the third embodiment. 
         FIG. 9  shows the exploded view of the blade set of the fourth embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is further described in detail with the following embodiments and the accompanying drawings.  FIGS. 1 to 5  illustrate the first embodiment of the present invention. As illustrated in  FIGS. 1 and 2 , the present invention comprises a lower fixed blade  1 , an upper fixed blade  2 , a movable blade assembly  3  and a blade holder  71 . The lower fixed blade  1  is provided with a first toothed front edge  11 . The upper fixed blade  2  is provided with a second toothed front edge  21  which is disposed on top of the lower fixed blade  1  and aligned corresponding to the lower fixed blade  1  so that the teeth  12 ,  22  of the first toothed front edge  11  and the second toothed front edge  12  do not overlap with each other. The movable blade assembly  3  is disposed in between the lower fixed blade  1  and the upper fixed blade  2  and is connected to a driving means  4  driven by a driving unit (not shown) in the hair clipper  6  to reciprocate laterally relative to the lower fixed blade  1  and the upper fixed blade  2  in an operating condition. The blade holder  71  secures the lower fixed blade  1 , the movable blade assembly  3  and the upper fixed blade  2  together to form a blade set and the blade set is connected to the hair clipper  6 . The blade holder  71  comprises a pressing piece  7  and a base  8  secured under the lower fixed blade  1  and connected to the pressing piece  7 . The pressing piece  7  presses against a top surface of the upper fixed blade  2 . The base  8  is provided with a recess  84  at its front end for receiving the lower fixed blade  1 , and the shape of the recess  84  corresponds to that of the lower fixed blade. 
     The movable blade assembly  3  in this embodiment comprises one blade with a third toothed front edge  31  and each tooth thereof has a cross-sectional shape of a rectangle. The third toothed front edge  31  is provided at a front end of the movable blade assembly  3 . A lower portion  32  of the third toothed front edge  31  cooperates with an upper portion  13  of the first toothed front edge  11  to define a first cutting surface. An upper portion  33  of third toothed front edge cooperates with a lower portion  23  of the second toothed front edge  21  to define a second cutting surface. 
     In this embodiment, the base  8  is provided with two pins  81  which extend upward towards a lower surface of the pressing piece  7  and pass through corresponding openings  15 ,  35 ,  25  provided on each of the lower fixed blade  1 , the movable blade assembly  3  and the upper fixed blade  2 , thereby securing the lower fixed blade  1 , the movable blade assembly  3  and the upper fixed blade  2  in an assembled relation. The size of each opening  35  of the movable blade assembly  3  is larger than that of the corresponding pin  81  so as to allow reciprocating actions of the movable blade assembly  3 . A guarding piece  37  is disposed on top of each opening  35  of the movable blade assembly  3  for protecting the movable blade assembly  3  from wear and tear during reciprocation. 
     In this embodiment, the base  8  and the pressing piece  7  are connected to each other by means of a torsion spring  9 . The torsion spring  9  comprises a coil member  91  and two ends  92 ,  93  and is connected to the base  8  via a rod  94 . The rod  94  passes through the coil member  91  and is disposed at a rear end of the base  8 . The two ends  92 ,  93  of the torsion spring  9  are attached to the pressing piece  7 , and the pressure exerted by the pressing piece  7  against the upper fixed blade  2 , the movable blade assembly  3  and the lower fixed blade  1  enables the three blades to be secured in an assembled relation. The rear end of the base  8  is provided with two walls  82 A,  82 B opposite to each other, one on the left side and one on the right side, and each wall  82 A,  82 B is provided with a through hole  83 A,  83 B in the middle for receiving one end of the rod  94 . 
     In this embodiment, the driving means  4  is provided with a connecting piece  41 , and the upper fixed blade  2 , the lower fixed blade  1  and the movable blade assembly  3  are each provided with a notch  26 ,  16 ,  36  corresponding to the connecting piece  41  for receiving the connecting piece  41 . The connecting piece  41  passes through corresponding notches  26 ,  36 ,  16  provided on each of the upper fixed blade  2 , the movable blade assembly  3  and the lower fixed blade  1 . The size of each notch  26 ,  16  of the upper fixed blade  2  and the lower fixed blade  1  is larger than that of the corresponding connecting piece  41  so as to allow reciprocating action of the connecting piece  41 . In other embodiments, it is possible for the connecting piece to pass through the corresponding notch in the movable blade assembly only. The base  8  is provided with two protrusions  87 , one on left side and one on right side, for connecting the blade set to the hair clipper  6 . 
       FIGS. 6 and 7  illustrate the second embodiment of the present invention. The second embodiment is similar to the first embodiment except for the following. In this embodiment, the movable blade assembly comprises a lower movable blade  3 A provided with a toothed front edge constituting the lower portion  32  of the third toothed front edge  31  in the first embodiment, and an upper movable blade  3 B disposed fixedly on top of the lower movable blade  3 A and provided with a toothed front edge constituting the upper portion  33  of the third toothed front edge  31  in the first embodiment. The toothed front edge of the lower movable blade  3 A and the toothed front edge of the upper movable blade  3 B overlap with each other. Each tooth of the toothed front edge of the lower movable blade  3 A has a cross-sectional shape of an isosceles trapezoid, and each tooth of the toothed front edge of the upper movable blade  3 B has a cross-sectional shape of an inverted isosceles trapezoid. Other structures of this embodiment are similar to those of the first embodiment and are therefore not described in detail. 
       FIG. 8  illustrates the third embodiment of the present invention. The third embodiment is similar to the first embodiment except for the following. In this embodiment, each tooth  12  of the first toothed edge  11  of the lower fixed blade  1  is integrally provided with a first protecting piece  14  extending upward from a front end thereof, and each tooth  22  of the second toothed  21  edge of the upper fixed blade  2  is integrally provided with a second protecting piece  24  extending downward from a front end thereof. The thickness of the first and second protecting pieces  14 ,  24  is adapted to allow the movable blade assembly  3  to reciprocate laterally. The first and second protecting pieces  14 ,  24  protect the user&#39;s hand from getting injured by the movable blade assembly. Other structures of this embodiment are similar to those of the first embodiment and are therefore not described in detail. 
       FIG. 9  illustrates the fourth embodiment of the present invention. The fourth embodiment is similar to the first embodiment except for the following. In this embodiment, a spring plate  10  is disposed on top of the pressing piece  7  to exert pressure against the pressing piece  7 . A rear end of the base  8  is provided with two nuts  85 A,  85 B, one on the left side and one on the right side, for receiving two screws  86 A,  86 B which pass through two corresponding holes  101 ,  102  on the spring plate  10 . Other structures of this embodiment are similar to those of the first embodiment and are therefore not described in detail. 
     As to a further discussion of the manner of usage and operation of the present invention, the same should be apparent from the above description. Accordingly, no further discussion relating to the manner of usage and operation is provided. 
     With respect to the above description, it is to be realized that the optimum relationships for the parts of the invention in regard to size, shape, form, materials, function and manner of operation, assembly and use are deemed readily apparent and obvious to those skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. 
     The present invention is capable of other embodiments and of being practiced and carried out in various ways. It is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. 
     Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to falling within the scope of the invention.