Abstract:
The present invention provides a double-blade hair trimming device which comprises a blade body, a blade head, and a driving device disposed inside the blade body, wherein the blade head comprises a thick blade unit and a thin blade unit which are disposed side by side. The present invention is provided with both the thick blade unit which is used to trim hard, thick and long hair and the thin blade unit which is used to trim short and fine hair. Hair on the skin can be tidily trimmed by just one shave or one shave in each of two opposite directions. The length of the hair after shaving is less than 0.1 mm. It is safe and convenient to use.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to the field of electric personal care product, and more specifically relates to a kind of double-blade hair trimming device. 
         [0002]    At present, a hair trimming device comprises a foil in the middle and trimming blades on the two sides. The disadvantage is that after using the trimming blade, it is difficult for a user to align the hair with the meshes of the foil and put the hair through. The user needs to move back and forth repeatedly in order to finish trimming by the foil. Yet, during the reciprocating movement, the trimming blade may trim away the hair that the user may like to keep. In the case of armpit hair-trimming, the trimming blades may cut the skin when using the foil. 
         [0003]    There is another type of hair trimming device, wherein a razor is added onto the trimming device. The razor can be hidden, so in this case the trimming device can be used alone. Alternatively, the razor can be extended. The longer hair can first be trimmed by the trimming device disposed in the front position. After that, the razor disposed in the back position can be used to shave. Another option is that the razor can be extended fully such that it can be used directly. The disadvantage is that this combination of blade heads is difficult to control. One needs to manage the use angles of the trimming device and the razor at the same time. The user may worry that the razor may cut the skin and affect the trimming effects, especially on the sensitive area. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    In view of the aforesaid disadvantages now present in the prior art, the present invention provides a kind of double-blade trimming device which is safer to use. 
         [0005]    The present invention adopts the following technical proposal: 
         [0006]    A double-blade hair trimming device which comprises a blade body, a blade head, and a driving device disposed inside the blade body, wherein the blade head comprises a thick blade unit and a thin blade unit which are disposed side by side. 
         [0007]    The thick blade unit is a thick blade assembly, whereas the thin blade unit is a thin blade assembly. The thick blade assembly and the thin blade assembly are disposed in the same direction. The thin blade assembly is disposed rear to the thick blade assembly. 
         [0008]    The thick blade assembly comprises a thick fixed blade and a first movable blade. The thin blade assembly comprises a thin fixed blade and a second movable blade. The thick fixed blade, the first movable blade, the thin fixed blade and the second movable blade each has an edge which is provided with a teeth section. The first movable blade is sleeved within an inner side of thick fixed blade, and the teeth sections thereof overlap with each other correspondingly. The first movable blade moves reciprocally corresponding to the thick fixed blade; when the teeth sections of the first movable blade and the thick fixed blade engage with each other, a thick blade trimming surface is formed without any gaps therebetween. The second movable blade is sleeved within an inner side of thin fixed blade, and the teeth sections thereof overlap with each other correspondingly. The second movable blade moves reciprocally corresponding to the thin fixed blade; when the teeth sections of the second movable blade and the thin fixed blade engage with each other, a thin blade trimming surface is formed without any gaps therebetween. The thick blade trimming surface and the thin blade trimming surface are disposed side by side and face the same direction. The thin fixed blade has a tooth thickness of less than 0.1 mm. 
         [0009]    The teeth section of the thick fixed blade comprises serrated openings which are evenly arranged on an edge thereof along a lengthwise direction. The teeth section of the first movable blade comprises a plurality of teeth which are evenly arranged on an edge thereof along a lengthwise direction, wherein each of the teeth has a V-shaped pointing end, a V-shaped cross section, and two edges which are both disposed with blades. The teeth section of the thin fixed blade comprises a plurality of teeth which are evenly arranged along an edge thereof along a lengthwise direction, wherein each of the teeth has a V-shaped pointing end and two edges which are both disposed with blades. The teeth section of the second movable blade comprises a plurality of teeth which are evenly arranged along an edge thereof along a lengthwise direction, wherein each of the teeth has a V-shaped pointing end and two edges which are both disposed with blades. 
         [0010]    The blade head also comprises a blade head protection line which is disposed between the teeth of the thick fixed blade and the thin fixed blade, and is parallel to the thick blade trimming surface and the thin blade trimming surface. Specifically, it is disposed at a front end of the thin fixed blade. When the present invention is in use, the thick blade assembly is first used to shave the skin, then the blade head protection line will stretch the skin which has been shaved by the thick blade assembly. Afterwards, the thin blade assembly is used to shave. 
         [0011]    The blade head protection line is an independent component, or a protrusion on a surface of the thick fixed blade, or an elongated component of the blade head protection cover which is parallel to both the thick blade trimming surface and the thin blade trimming surface. 
         [0012]    The blade head comprises a blade head cover case which is used to accommodate the thick blade assembly and the thin blade assembly. 
         [0013]    The blade head comprises a blade head protection cover which is engaged with the blade head cover case. The blade head protection cover has a side edge which is provided with a row of openings corresponding to shape, density and size of spacing of the teeth of the thick fixed blade, forming a guiding groove which facilitates entry of hair between the teeth of the first movable blade. 
         [0014]    The teeth of the thick fixed blade are engaged with an end of the row of openings of the blade head protection cover. The teeth of the first movable blade are concealed within a cavity formed by the engagement of the teeth of the thick fixed blade and the row of openings. 
         [0015]    The thick blade unit is a thick blade teeth edge, whereas the thin blade assembly is a thin blade teeth edge. The thick blade teeth edge and the thin blade teeth edge are reversely disposed. 
         [0016]    The blade head comprises a fixed blade and a movable blade. Axes of the fixed blade and the movable blade overlap. The fixed blade and the movable blade are each provided with teeth sections at two opposite edges thereof. The fixed blade is sleeved within an inner side of the movable blade. The teeth sections of the fixed blade and the movable blade overlap with each other correspondingly. The movable blade moves reciprocally corresponding to the fixed blade to trim away hair. One of the edges of the fixed blade is relatively thicker than the edge opposite thereto. The thicker edge of the fixed blade overlaps with one of the edges of the movable blade to form the thick blade teeth edge. The thinner edge of the fixed blade overlaps with the other edge of the movable blade to form the thin blade teeth edge. Inner sides of the teeth sections of the fixed blade of the thick blade teeth edge and the thin blade teeth edge are engaged with outer sides of the teeth sections of the movable blade of the thick blade teeth edge and the thin blade teeth edge without any gaps to form trimming surfaces for hair trimming. The teeth section of the thinner edge of the fixed blade has a tooth thickness of less than 0.1 mm. 
         [0017]    The teeth section of the thicker edge of the fixed blade comprises serrated openings which are evenly arranged along a lengthwise direction of that edge. The teeth section of the thinner edge of the fixed blade comprises a plurality of teeth which are evenly arranged along a lengthwise direction of that edge, wherein each of the teeth has a V-shaped pointing end and two edges which are both disposed with blades. 
         [0018]    The teeth sections of the two edges of the movable blade each comprises a plurality of teeth which are evenly arranged along a lengthwise direction of the edge; each of the teeth has a V-shaped pointing end, a V-shaped cross section, and two edges which are both disposed with blades. 
         [0019]    The blade head also comprises a blade head protection line which is disposed at a side of thin blade teeth edge which is far away from the thick blade teeth edge. It is parallel to both the thin blade teeth edge and the thick blade teeth edge and is located on the same plane as an outer surface of the fixed blade. 
         [0020]    The blade head protection line is an independent component, with its two ends fixed onto a case of a double-sided double-blade hair trimming device. 
         [0021]    The blade head protection line can also be an elongated protrusion on a surface of a case of a double-sided double-blade hair trimming device which is parallel to both the thick blade teeth edge and the thin blade teeth edge. 
         [0022]    Compared with the prior art, the present invention has the following advantages: 
         [0023]    When carrying out a first shave with the double-sided double-blade hair trimming device of the present invention, the thick blade teeth edge can remove the thick and long hair. After that, by shaving in a reverse way, the remaining short and fine hair will be removed by the thin blade teeth edge. The length of the hair of the skin being shaved can be less than 0.1 mm, thus attaining the effect of a razor. The blade head protection line can stretch and flatten the skin which has been shaved by the thick blade teeth edge, hence the rough area of the skin will not be scratched by the thin blade assembly during shaving. Also, the present invention is suitable for shaving twice in opposite directions. This allows the user to shave away all thick and long hair during the first shave, and keep the hair he likes during the second shave. The present invention is simple in structure and convenient to use. 
         [0024]    The single-sided double-blade hair trimming device of the present invention is disposed with a thick blade assembly and a thin blade assembly at the same trimming direction. Thick and long hair can be removed by the thick blade assembly by only one shave without the need for accurate alignment, and the remaining short and fine hair can be removed by the thin blade assembly. The length of the hair of the skin being shaved can be less than 0.1 mm. The blade head protection line can stretch and flatten the skin which has been shaved by the thick blade assembly, hence the rough area of the skin will not be scratched by the thin blade assembly during shaving. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  illustrates a sectional view of the overall structure of the present invention according to Embodiment  1 ; 
           [0026]      FIG. 2  illustrates a structural schematic view of the exposed blade head of  FIG. 1  excluding the blade head cover case; 
           [0027]      FIG. 3  illustrates a structural schematic view of the blade head of  FIG. 2  including the blade cover case; 
           [0028]      FIG. 4  illustrates an exploded schematic view of the blade head of  FIG. 1 ; 
           [0029]      FIG. 5  illustrates a schematic view of the overall structure of the present invention according to Embodiment  2 ; 
           [0030]      FIG. 6  illustrates a structural schematic view of the fixed blade; 
           [0031]      FIG. 7  illustrates a structural schematic view of the movable blade. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiment 1 
       [0032]    As illustrated in  FIGS. 1 to 4 , the single-sided double-blade hair trimming device of the present invention comprises a top case  1  and a bottom case  2  which are engaged with each other to form a case. It further comprises a switch  5 , a battery  3 , a motor  4  and a double eccentric shaft  6  which are disposed inside the case and are connected in sequence from a rear end to a front end of the case. Two shaft ends of the double eccentric shaft  6  are respectively connected to a thin blade rocker arm  7  and a thick blade rocker arm  8 . The thin blade rocker arm  7  and the thick blade rocker arm are connected to a blade head  9 , wherein the switch  5 , the battery  3  and the motor  4  are connected by circuits. The front end of the bottom case  2  is provided with a blade head cover case  29 . 
         [0033]    The blade head  9  comprises a thick blade assembly  91  and a thin blade assembly  92  which are disposed side by side and in the same direction. The thick blade assembly  91  comprises a first movable blade holder  11 , a first movable blade  12  and a thick fixed blade  13 . The thin blade assembly  92  comprises a second movable blade holder  14 , a second blade  15  and a thin fixed blade  16 . The lengths of the first movable blade holder  11  and the first movable blade  12  are shorter than the length of the thick fixed blade  13 , whereas the lengths of the second movable blade holder  14  and the second movable blade  15  are shorter than the length of the thin fixed blade  16 . 
         [0034]    The thick fixed blade  13 , the first movable blade  12 , the thin fixed blade  16  and the second movable blade  15  each has an edge which is provided with a teeth section. The first movable blade  12  is sleeved within an inner side of the thick fixed blade  13 , and the teeth sections thereof overlap with each other correspondingly. The first movable blade  12  moves reciprocally corresponding to the thick fixed blade  13 ; when the teeth sections thereof engage with each other, a thick blade trimming surface  21  is formed without any gaps therebetween. The second movable blade  15  is sleeved within an inner side of the thin fixed blade  16 , and the teeth sections thereof overlap with each other correspondingly. The second movable blade  15  moves reciprocally corresponding to the thin fixed blade  16 ; when the teeth sections thereof engage with each other, a thin blade trimming surface  31  is formed without any gaps therebetween. The thick blade trimming surface  21  and the thin blade trimming surface  31  are disposed side by side and face the same direction. 
         [0035]    The teeth section of the thick fixed blade  13  comprises serrated openings which are evenly arranged on an edge thereof along a lengthwise direction. The teeth section of the first movable blade  12  comprises a plurality of teeth which are evenly arranged on an edge thereof along a lengthwise direction; each of the teeth has a V-shaped pointing end, a V-shaped cross section, and two edges which are both disposed with blades. The teeth section of the thin fixed blade  16  comprises a plurality of teeth which are evenly arranged on an edge thereof along a lengthwise direction; each of the teeth has a V-shaped pointing end and two edges which are both disposed with blades. The teeth section of the second movable blade  15  comprises a plurality of teeth which are evenly arranged on an edge thereof along a lengthwise direction; each of the teeth has a V-shaped pointing end and two edges which are both disposed with blades. 
         [0036]    The first movable blade holder  11  has a top side which is disposed with two protrusions  111  for clamping an end of the thick blade rocker arm  8 , so as to fix the first movable blade holder  11  with the thick blade rocker arm  8 . The top side and a bottom side of the first movable blade holder  11  are each disposed with two cylindrical positioning protrusions  112  at two ends thereof. The first movable blade  12  is disposed with two mounting holes  121  which fit with the two positioning protrusions  112  of the bottom side of the first movable blade holder  11 . The first movable blade holder  11  and the first movable blade  12  are fixed with each other by engaging the two positioning protrusions  112  with the mounting holes  121 . Two springs  33  are provided, with one end of each pressing against the blade head cover case  29  and the other end of each sleeved within each of the two positioning protrusions  112  disposed on the top side of the first movable blade holder  11 ; the first movable blade  12  is pressed by pressing the first movable blade holder  11 . Two ends of the thick fixed blade  13  are each disposed with a screw hole  131 . The thick fixed blade  13  is mounted on the blade head cover case  29  by engaging the blade locking screws  44  and the blade locking nuts  55 . Specifically, the blade locking nuts  55  are first securely mounted into the blade head cover case  29 ; the thick fixed blade  13  is then placed thereon, and lastly the blade locking screws  44  are mounted. The first movable blade  12  and the first movable blade holder  11  are disposed between the thick fixed blade  13  and the blade head cover case  29 . The teeth of the first movable blade  12  and the thick fixed blade  13  face the same direction. 
         [0037]    The blade head  9  also comprises a blade head protection cover  18 , which is engaged with the blade head cover case  29 . The blade head protection cover  18  has a side edge which is provided with a row of openings  181  corresponding to density and size of the teeth of the thick fixed blade  13 . The teeth of the thick fixed blade  13  are engaged with an end of the row of openings  181 . The teeth of the first movable blade  12  are concealed within a cavity formed by the engagement of the teeth of the thick fixed blade  13  and the row of openings  181 . 
         [0038]    The second movable blade holder  14  has a top side which is disposed with two protrusions  141  for clamping an end of the thin blade rocker arm  7 , so as to fix the second movable blade holder  14  and the thin blade rocker arm  7 . The top side and a bottom side of the second movable blade holder  14  are each disposed with two cylindrical positioning protrusions  142  at two ends thereof. The second movable blade  15  comprises two mounting holes  151  which fit with the two positioning protrusions  142  of the bottom side of the second movable blade holder  14 . The second movable blade holder  14  and the second movable blade  15  are fixed with each other by engaging the two positioning protrusions  142  with the mounting holes  151 . Two springs  33  are provided, with one end of each pressing against the blade head cover case  29  and the other end of each sleeved within each of the two positioning protrusions  142  disposed on the top side of the second movable blade holder; the second movable blade  15  is pressed by pressing the second movable blade holder  14 . Two ends of the thin fixed blade  16  are each disposed with a screw hole  161 . The thin fixed blade  16  is mounted on the blade head cover case  29  by engaging the blade locking screws  44  and the blade locking nuts  55 . Specifically, the blade locking nuts  55  are first securely mounted into the blade head cover case  29 ; the thin fixed blade  16  is then placed thereon, and lastly the blade locking screws  44  are mounted. The second movable blade  15  and the second movable blade holder  14  are disposed between the thin fixed blade  16  and the blade head cover case  29 . The teeth of the second movable blade  15  and the thin fixed blade  16  face the same direction. 
         [0039]    The blade head  9  also comprises a blade head protection line  17  which is disposed between the thick fixed blade  13  and the thin fixed blade  16 , and is parallel to the edges of the thick fixed blade  13  and the thin fixed blade  16  which are disposed with teeth sections, wherein the two ends thereof are fixed onto an inner side surface of the blade head cover case  29  so as to stretch the skin which has been shaved by the first movable blade  12 , thereby preventing the skin from bulging and being cut by the second movable blade  15 . 
         [0040]    The blade head protection line  17  can be an elongated component of the blade head cover case  29  which is disposed between the thick blade assembly  91  and the thin blade assembly  92 . 
         [0041]    The blade head protection line can be a wall-like elongated protrusion protruded from a surface of the thick fixed blade  13 . 
         [0042]    The thick fixed blade  13  forms a certain angle with the thin fixed blade  16 , or the two are on the same plane. 
         [0043]    The teeth of thin fixed blade  16  are ultrathin with a thickness of less than 0.1 mm, preferably 0.07 mm. 
         [0044]    The teeth of thick fixed blade  13  can be separated from the end of the row of openings  181  of the blade head protection cover  18 , and thus leaving a gap therebetween. This allows the hair inside the blade head cover case  29  to be washed away from the gap. 
       Embodiment 2 
       [0045]    As illustrated in  FIGS. 5 to 7 , the double-sided double-blade trimming device of the present embodiment comprises a blade body  20  and a blade head  10 . The blade body  20  is disposed with a driving device therein. The blade head  10  comprises a thick blade teeth edge  110  and a thin blade teeth edge  120 . 
         [0046]    Specifically, the blade head  10  comprises a fixed blade  30  and a movable blade  40 . Axes of the fixed blade  30  and the movable blade  40  overlap. The fixed blade  30  and the movable blade  40  are each provided with teeth sections  310 ,  320 ,  410 ,  420  at two opposite edges thereof. The fixed blade  30  is sleeved within an inner side of the movable blade  40 . The teeth sections  310 ,  410  of the fixed blade  30  and the movable blade  40  overlap with each other correspondingly; the teeth sections  320 ,  420  overlap with each other correspondingly. The movable blade  40  moves reciprocally corresponding to the fixed blade  30  to trim away the hair. One of the edges of the fixed blade  30  is relatively thicker than the edge opposite thereto. One of the edges of the movable blade  40  is relatively thicker than the edge opposite thereto. The thicker edge of the fixed blade  30  overlaps with one of the edges of the movable blade  40  to form the thick blade teeth edge  110 . The thinner edge of the fixed blade  30  overlaps with the other edge of the movable blade  40  to form the thin blade teeth edge  120 . Inner sides of the teeth sections  310 ,  320  of the fixed blade of the fixed blade teeth edge  110  and the thin blade teeth edge  120  are engaged with outer sides of the teeth sections  410 ,  420  of the movable blade without any gaps to form trimming surfaces for hair trimming. 
         [0047]    The teeth section  310  of the thicker edge of the fixed blade  30  comprises serrated openings which are evenly arranged along a lengthwise direction of that edge. The teeth section  320  of the thinner edge of the fixed blade  30  comprises a plurality of teeth which are evenly arranged along a lengthwise direction of that edge; each of the teeth has a V-shaped pointing end, and two edges which are both disposed with blades. 
         [0048]    The teeth section  410  of the thicker edge of the movable blade  40  comprises a plurality of teeth which are evenly arranged along a lengthwise direction of that edge; each of the teeth has a V-shaped pointing end, a V-shaped cross section, and two edges which are both disposed with blades. The teeth section  420  of the thinner edge of the movable blade  40  comprises a plurality of teeth which are evenly arranged along a lengthwise direction of that edge; each of the teeth has a V-shaped pointing end and two edges which are both disposed with blades. 
         [0049]    The blade head  10  also comprises a blade head protection line  130  which is disposed at a side of the thin blade teeth edge  120  which is far away from the thick blade teeth edge  110 . 
         [0050]    The blade head protection line  130  is an independent component, with its two ends fixed onto a case of the double-sided double-blade hair trimming device. 
         [0051]    The blade head protection line  130  can also be an elongated protrusion on a surface of the case of the double-sided double-blade hair trimming device. It is parallel to both the thick blade teeth edge  110  and the thin blade teeth edge  120 . 
         [0052]    The teeth section  320  of the thinner edge of the fixed blade  30  has a tooth thickness of less than 0.1 mm. 
         [0053]    The tooth thickness of the teeth sections of the two opposite edges of the movable blade  40  can be the same. After trimming, the length of the hair is determined by the tooth thickness of the teeth section of the fixed blade  30 , therefore the present embodiment does not set limits to the relative thickness and absolute thickness of the teeth sections of the two opposite edges of the movable blade  40 . 
         [0054]    The above embodiments described in greater detail are only a few embodiments of the present invention and should not limit the scope of the present invention. To any person skilled in this field of art, any change and modification without deviating from the concept of the present invention should also fall within the scope of protection of the present invention. The scope of protection of the present invention should be limited by the claims.