Patent Publication Number: US-2011061241-A1

Title: Pressure adjustable knife set for electromotive hair cutter

Description:
FIELD OF THE INVENTION 
     The present invention relates to hair cutters, and particularly to a pressure adjustable knife set for an electromotive hair cutter 
     BACKGROUND OF THE INVENTION 
     The prior art electromotive hair cutter has a fixed knife and a movable knife. The movable knife moves reciprocally along the fixed knife for cutting hairs. The fixed knife has V shape cuts so that only little hairs are cut. Furthermore, the tightness between the fixed knife and the movable knife is related to the smooth of the cutting. If the pressure is too light, the knife is not sharp enough to cut the hair effectively. If the applied pressure is too great, the friction will be too large so that the knife will heat to burn the skin and thus the hair cutter must be shut down for cooling. The cutter is not useful and the knife is worn quickly and thus the lifetime is short. The motor of the cutter has a great burden and thus has a short lifetime. 
     SUMMARY OF THE INVENTION 
     Accordingly, the object of the present invention is to provide a pressure adjustable knife set for an electromotive hair cutter comprising: a fixed knife, a movable knife, and a pressure adjust unit for adjusting pressures between the two knives; a front edge of the fixed knife having a cutting edge; the fixed knife being formed with a penetrating hole for passing through the adjustable screw of the pressure adjusting unit; a front edge of the movable knife being formed with a cutting edge; a lower side of the movable knife being formed with a supporting leg; the supporting leg being formed with a plurality of heat dissipating holes with the functions of heat dissipation and reduction of the friction area of the supporting legs; the movable knife being formed with a long penetrating trench; and a fixing plate being installed between the fixed knife and the pressure adjusting unit; an adjustable screw passing through a penetrating hole of the fixed knife, the movable knife and the pressure adjusting unit. A front edge of the fixed knife  1  has a cutting edge with a plurality of U shape recesses. Each of two ends at a bottom of the long penetrating trench is formed with a heat dissipating notch which is opened at lateral side of the movable knife. A spring circles the adjustable screw between the movable knife and the pressure adjusting unit for tightening the adjustable screw; and the adjustable screw serves to adjust the pressing force of the pressure adjusting unit. 
     The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an embodiment of the present invention. 
         FIG. 2  is an assembled perspective view of the present invention. 
         FIG. 3  is a cross sectional view along line  3 - 3  of  FIG. 2 . 
         FIG. 4  is a cross sectional view along line  4 - 4  of  FIG. 2 . 
         FIG. 5  is a schematic view about the pressure adjustment of the present invention (reduction of pressure between knives). 
         FIG. 6  is a schematic view about the pressure adjustment of the present invention (increasing of pressure between knives). 
         FIG. 7  is an elevational view of the present invention. 
         FIG. 8  is a lateral view of  FIG. 7 . 
         FIG. 9  is an upper view of the present invention. 
         FIG. 10  is an elevational view of the movable knife of the present invention. 
         FIG. 11  is a right side view of  FIG. 10 . 
         FIG. 12  is an elevational view of  FIG. 10 . 
         FIG. 13  is an elevational view of second embodiment about the movable knife. 
         FIG. 14  is a right side view of  FIG. 13 . 
         FIG. 15  is an upper view of  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In order that those skilled in the art can further understand the present invention, a description will be provided in the following in details. However, these descriptions and the appended drawings are only used to cause those skilled in the art to understand the objects, features, and characteristics of the present invention, but not to be used to confine the scope and spirit of the present invention defined in the appended claims. 
     Referring to  FIGS. 1 to 4 , the pressure adjustable knife set for an electromotive hair cutter according to the present invention is illustrated. The knife set includes a fixed knife  1 , a movable knife  2 , and a pressure adjust unit  3  for adjusting pressures between the two knives. 
     With referring to  FIGS. 7 to 9 , a front edge of the fixed knife  1  has a cutting edge  11  with a plurality of U shape recesses. The fixed knife  1  is formed with a penetrating hole  12  for passing through the screw  31  of the pressure adjusting unit  3  and two penetrating holes  13  for passing the screws  41  for fixing the fixed knife  1  to a fixing portion of an electromotive hair cutter. An upper side of the fixed knife  1  has a protruding strip  14  for installing the supporting leg  20  of the movable knife  2 . 
     With referring to  FIGS. 10 to 12 , a front edge of the movable knife  2  is formed with a cutting edge  21  with a plurality of V shape recesses  21  and a plurality of V shape cutting tips. A rear edge of the movable knife  2  is formed with a notch  22 . A lower side of the movable knife  2  is formed with supporting leg  20  which can be installed upon the protruding strip  14  of the fixed knife  1 . The supporting leg  20  is formed with a plurality of heat dissipating holes  23  with the functions of heat dissipation and reduction of the friction area of the supporting legs  20 . The movable knife  2  is formed with a long penetrating trench  24 . A rectangular positioning trench  25  is formed between the cutting edge  21  of the movable knife  2  and the long penetrating trench  24  for movably receiving a pressing portion  33  at a front edge of the pressure adjusting unit  3 . Each of two ends at a bottom of the long penetrating trench  24  is formed with a heat dissipating notch  26  which is opened at lateral side of the movable knife  2 .  FIGS. 13 to 15  show the second embodiment of the moveable knife  2  of the present invention. It is illustrated that no notch  26  at two ends of the long penetrating trench  24 . 
     With referring to  FIGS. 1 to 4 , a fixing plate  4  is installed between the fixed knife  1  and the pressure adjusting unit  3  by using a screw  41  to pass through the pressure adjusting unit  3  and the fixed knife  1  and another screw  41  to pass through the fixing plate  4  and the fixed knife  1 . An adjustable screw  31  passes through a penetrating hole  12  of the fixed knife  1 , the notch  22  of the movable knife  2  and a screw hole  30  of the pressure adjusting unit  3 . A spring  32  circles the adjustable screw  31  between the movable knife  2  and the pressure adjusting unit  3  for tightening the adjustable screw  31 . The adjustable screw  31  serves to adjust the pressing force of the pressure adjusting unit  3 . 
     With referring to  FIGS. 5 and 6 , the adjustment of the adjustable screw  31  will adjust the tighten state between the fixed knife  1  and the movable knife  2 . Furthermore, with the U shape cutting edge  11  of the fixed knife  11 , a preferably cutting effect is achieved with more hairs entering into the cutting edge. 
     The present invention is thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.