Patent Publication Number: US-2012023762-A1

Title: Handle for bladed hand tool and razor

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a handle for a bladed hand tool and a razor. 
     Conventionally, Japanese Laid-Open Patent Publication No. 2010-64170 discloses the structure of a handle for a bladed hand tool. According to the structure disclosed by the document, the surface of the handle includes, in addition to a part formed of hard resin, an exposed part formed of soft resin. When one&#39;s fingers are pressed against the handle surface to hold the handle, the disclosed structure is not likely to provide changes in gripping sensation. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an objective of the present invention to improve the sensation experienced when one&#39;s fingers are pressed against the surface of a handle, such as a handle for bladed hand tool such as razor, to grip the hand tool. 
     To achieve the foregoing objective and in accordance with one aspect of the present invention, a handle for a bladed hand tool is provided that includes a grip portion and a pair of finger rest portions. The grip portion is held by a user and includes two side sections. The finger rest portions are provided on both side sections of the grip portion with respect to a widthwise direction, and extend along a longitudinal direction of the grip portion. Each finger rest portion is divided into a plurality of sections along the thickness direction of the grip portion, and different sections of the finger rest portions are displaced by different amounts when one of the finger rest portions is pressed toward the other to cause the finger rest portions to approach each other. 
     In accordance with another aspect of the present invention, a handle for a bladed hand tool is provided that includes a grip portion. The grip portion is held by a user and includes two end portions. A top portion is provided at one of the two end portions of the grip portion in the longitudinal direction, and a tail portion is provided at the other end portion. The razor head incorporating a blade set is attached to the top portion. The grip portion has a front section located on a side in which the edge of the blade body faces, a back section on a side opposite to the front section, and side sections on both sides in the widthwise direction and between the top portion and the tail portion. The front section has a space that is located between the side sections and extends along the longitudinal direction of the grip portion. Each side section has a finger rest portion. The finger rest portions sandwich the space along the widthwise direction and extending along the longitudinal direction. Each finger rest portion is formed like a cantilever such that one of the end portions in the thickness direction of the grip portion is a free end, and the other end is a fixed end. The space is opened between the free ends of the finger rest portions. The finger rest portions are attached, at the fixed ends, to the base portion of the grip portion. The base portion is formed of a material that is harder than the finger rest portion. The finger rest portions are flexed into the space when pressed toward the space, and at the flex, the amount of flex increases from the fixed end toward the free end. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a front perspective view illustrating a razor according to one embodiment of the present invention; 
         FIG. 1B  is a rear perspective view illustrating the razor; 
         FIG. 2A  is a front view illustrating the handle of the razor; 
         FIG. 2B  is a rear view illustrating the handle of the razor; 
         FIG. 3A  is a side view illustrating the razor; 
         FIG. 3B  is a longitudinal cross-sectional view illustrating the razor; 
         FIG. 4A  is a cross-sectional view taken along line  4 A- 4 A in  FIG. 3A ; and 
         FIG. 4B  is a cross-sectional view taken along line  4 B- 4 B of  FIG. 3A . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, a bladed tool according to one embodiment of the present embodiment will now be described with reference to  FIGS. 1 to 4B . In the present embodiment, the bladed tool is a razor handle. When describing the bladed hand tool according to the present embodiment, the longitudinal direction X of a grip portion of the handle is referred to as an up-down direction. The widthwise direction Y of the grip portion is referred to as a left-right direction. The direction Z along the thickness of the grip portion is referred to as a front rear direction. Further, the direction in which the edge of razor head faces is referred to as a forward direction. 
     As shown in  FIG. 1 , a razor  1  includes a handle  2  and a razor head  4 . The handle  2  includes a grip portion  3 , a top portion  6 , and a tail portion  7 . A blade set  5  is incorporated in the razor head  4 . The top portion  6  is provided at the upper end of the grip portion  3 , and the tail portion  7  is provided at the lower end of the grip portion  3 . The razor head  4  is attached to the handle  2  in the vicinity of the top portion  6 . The razor head  4  cannot be detached from the handle  2  and is supported to be swingable. The grip portion  3  includes a front section  8  facing forward, a back section  9  facing rearward, and a pair of side sections  10  facing leftward and rightward. The side sections  10  are provided between the top portion  6  and the tail portion  7 . The front section  8  has a space  11  defined between the side sections  10 . The space  11  extends along the longitudinal direction X from the top portion  6  to the tail portion  7 . 
     As shown in  FIGS. 2 to 4 , the grip portion  3  includes an annular support frame  12  and a wall  16  integrated with the support frame  12 . The support frame  12  is formed by a pair of side frame sections  13  (base portions) forming the side sections  10 , an end frame section  14  connecting the upper ends of the side frame sections  13 , and an end frame section  15  connecting the lower ends of the side frame sections  13 . The wall  16  has a peripheral wall section  17  and a back wall section  18  located inside the peripheral wall section  17 . The peripheral wall section  17  substantially extends as a loop along the side frame sections  13  and the end frame sections  14 ,  15 . The back wall section  18  is formed to be continuous to the peripheral wall section  17 . The space  11  is surrounded by the peripheral wall section  17  and the back wall section  18 . The space  11  is substantially closed by the back section  9  and opens forward. The support frame  12  is formed of a hard resin such as an ABS resin and a polypropylene resin. The wall  16  is formed of a soft resin such as an elastomer resin and a silicone resin. The hardness of the wall  16  is less than that of the support frame  12 . The hardness of the wall  16  is preferably shore A30 to shore D60. 
     The peripheral wall section  17  includes a pair of side walls  19 . The side walls  19  project forward from parts of the support frame  12  in the vicinity of the side frame sections  13 . The side walls  19  each have a finger rest wall  20  serving as a finger rest portion. A pair of the finger rest walls  20  is provided to sandwich the space  11  from left and right. The finger rest walls  20  extend from the top portion  6  to the tail portion  7  along the longitudinal direction X. A single finger rest recess  21  and a plurality of through holes  22  are formed on the back wall section  18 . The through holes  22  include larger holes and smaller holes. The finger rest recess  21  is formed adjacent to the frame end section  14  of the support frame  12 , and the through holes  22  are formed adjacent to the finger rest recess  21 . The larger holes and the smaller holes of the through holes  22  are arranged alternately. The through holes  22  remind the user of an image of bubbles in water. The side walls  19  each have a step  19   a  at the joint between the side wall  19  and the support frame  12  of the corresponding side frame section  13 . The steps  19   a  of the side walls  19  are heat welded to end faces  13   a  of the side frame sections  13 . 
     Each finger rest wall  20  is formed like a cantilever. The front end of each finger rest wall  20  is a free end  20   a , and the rear end of each finger rest wall  20  is a fixed end  20   b.  The finger rest walls  20  are attached to the side frame sections  13  at the fixed ends  20   b.  The space  11  is open between the free ends  20   a  of the finger rest walls  20 . Each finger rest wall  20  has an inner surface facing the space  11  and an outer surface  23  on the opposite side to the space  11 . The outer surfaces  23  of the finger rest walls  20  approach each other from the fixed ends  20   b  toward the free ends  20   a . Also, the free ends  20   a  of the finger rest walls  20  approach each other from the top portion  6  toward the tail portion  7 . Nonslip sections  23   a,  which are formed by an uneven surface, are arranged along the longitudinal direction X on the outer surface  23  of each finger rest wall  20 . Between the finger rest walls  20 , the through holes  22  are located at positions corresponding to the nonslip sections  23   a  (in range E shown in  FIG. 2A ). Each outer surface  23  has an apex  24  in an intermediate portion between the top portion  6  and the tail portion  7 . At the apex  24 , the distance between the fixed end  20   b  and the free end  20   a  on the outer surface  23 , that is, the measurement H 1  of the outer surface  23  along the direction Z of the thickness is the maximum, which is approximately 7 mm. The measurement H 1  of the outer surface  23  along the thickness direction Z gently changes toward the apex  24  from the top portion  6  and the tail portion  7 . The finger rest walls  20  are flexed by being pushed toward the space  11 . The amount of flex of the finger rest walls  20  increases from the fixed end  20   b  toward the free end  20   a.    
     A constricted part  25  exists between a part of each side section  10  that forms the finger rest wall  20  and a part of the side section  10  that forms the tail portion  7 . At the constricted parts  25 , the measurement W 1  in the widthwise direction Y of the handle  2 , that is, the distance between the side sections  10 , is the minimum, which is approximately 9 mm. The tail portion  7  is formed to be continuous to the constricted parts  25 . The tail portion  7  has a swell portion  7   a  that bulges in each of the forward, rearward, leftward, and rightward directions. The measurement W 2  of the swell portion  7   a  in the widthwise direction Y is approximately 22 mm. The tail portion  7  has a projection  7   b,  which slightly bulges in the direction Z of thickness of the back wall section  18 . The constricted parts  25  allow the grip portion  3  to be elastically deformed. Specifically, the constricted parts  25  allow the grip portion  3  to be flexed in a first direction, or along a line connecting the front section  8  and the back section  9  to each other, and in a second direction, or along a line connecting the side sections  10  to each other. The constricted parts  25  also allow the grip portion  3  to be twisted along a circumferential direction including the front section  8 , the back section  9 , and the side sections  10 . In other words, the grip portion  3  is flexed in the thickness direction Z, which corresponds to the first direction, and the widthwise direction Y, which corresponds to the second direction, and twisted about an axis extending along the longitudinal direction X. 
     The measurement of the outer surfaces  23  along the thickness direction Z decreases from the apexes  24  toward the constricted parts  25 . At the constricted parts  25 , the outer surfaces  23  of the finger rest walls  20  are gently continuous to the outer surfaces of the side walls  19 . At the constricted parts  25 , the measurement H 2  of the outer surface of each side wall  19  along the thickness direction Z is the minimum, which is approximately 2 mm. The measurement H 3  of the outer surface of each side wall  19  along the thickness direction Z gradually increases from the constricted part  25  toward the tail portion  7  and reaches approximately 3.5 mm. The lower end of the space  11  extends to the swell portion  7   a  of the tail portion  7 . A finger catch  17   a,  on which a finger can be placed, is formed at the lower end of the peripheral wall section  17 . The lower end of the peripheral wall section  17  forms the lower end of the space  11 . 
     The frame end section  14  of the support frame  12  is used as a support portion that supports the razor head  4  to the handle  2 . At the frame end section  14 , the measurement W 3  of the handle  2  in the widthwise direction Y is the maximum, which is approximately 23 mm. A support arm  26  is provided at each of the left and right ends of the frame end section  14 . The razor head  4  is pivotably supported at the upper end of the handle  2  with the pair of support arms  26 . A leaf spring  27  is provided at the center in the end frame section  14  in the widthwise direction Y. The razor head  4  is elastically urged by the leaf spring  27 . Specifically, the razor head  4  can be tilted rearward against the elastic force of the leaf spring  27  from a stationary position, in which the razor head  4  is urged forward by the elastic force of the leaf spring  27 . The space  11  is opened toward the end frame section  14 . The space  11  opens toward the razor head  4  through left and right sides of a small projection  14   a  of the frame end section  14 . The total length L of the razor  1  is approximately 130 mm. 
     When the handle  2  is held, the pulp of a user&#39;s thumb and the pulp of the user&#39;s index finger are pressed against the finger rest walls  20 . Alternatively, the pulp of the index finger is pressed against the finger rest recess  21  of the back section  9 , and the pulps of the thumb and middle finger are pressed against the finger rest walls  20 . In this state, the projection  7   b  of the tail portion  7  is pressed against the palm, and the swell portion  7   a  of the tail portion  7  is wrapped with the palm. Further, in this state, the little finger or ring finger is pressed against the finger catch  17   a  of the tail portion  7  via the space  11 . In this manner, by wrapping the swell portion  7   a  of the tail portion  7  with the palm, the tail portion  7  is stably held. Also, if the handle  2  is held with the thumb, index finger, or middle finger, the top portion  6  can be displaced by flexing the constricted parts  25 . 
     The present embodiment provides the following advantages. 
     (1) Each finger rest wall  20  is divided into sections along the thickness direction Z of the grip portion  3 , and the amount of displacement of the finger rest wall  20  varies depending on which section of the section  20  is pressed. That is, when a finger is pressed against the finger rest walls  20  while the handle  2  is held, the amount of displacement (the amount of flex) increases from the fixed end  20   b  toward the free end  20   a.  This allows the handle  2  to fit a user&#39;s hand or fingers. Accordingly, sensation experienced when the grip portion  3  is held and fingers are pressed against the finger rest walls  20  is improved. Particularly, if the razor  1  is a wet type, the handle  2  is stably held even when the handle  2  is wet and slippery. Also, since the handle  2  has the space  11  in the front section  8 , the finger rest walls  20  are easily deformed. Therefore, the fitting when the fingers are pressed against the finger rest walls  20  is further improved, and the feel is improved. 
     (2) The grip portion  3  can be elastically deformed at the constricted parts  25 . Specifically, the constricted parts  25  allow the grip portion  3  to be flexed in a first direction, or along a line connecting the front section  8  and the back section  9  to each other, and in a second direction, or along a line connecting the side sections  10  to each other. The constricted parts  25  also allow the grip portion  3  to be twisted along a circumferential direction including the front section  8 , the back section  9 , and the side sections  10 . Therefore, when being held, the handle  2  can be deformed in accordance with the force applied thereto. This allows the handle  2  to be comfortably fit with a user&#39;s hand and fingers, thereby further improving sensation experienced when fingers are pressed against the finger rest walls  20 . 
     (3) The side frame sections  13  are made of hard material. The side frame sections  13  therefore have rigidity. However, if the thickness is reduced, the side frame sections  13  are allowed to be flexed by external force. The side frame sections  13  can be flexed by pinching the back wall section  18 , particularly, to cause the finger rest walls  20  to approach each other. At this, the rigidity of the handle  2  is maintained by the rigidity of the side frame sections  13 . Since the finger rest walls  20  are more easily flexed than the side frame sections  13 , the handle  2  can fit fingers of the user. The constricted parts  25  are made of hard material and soft material. Also, the distance between the side frame sections  13  is reduced at the constricted parts  25 . Thus, the constricted parts  25  can be twisted or bent while maintaining certain rigidity. 
     (4) The through holes  22  are formed in the back wall section  18 . Between the finger rest walls  20 , the through holes  22  are located at positions corresponding to the nonslip sections  23   a  (in range E shown in  FIG. 2A ). Therefore, the through holes  22  allow the finger rest walls  20  to be easily flexed, so that the nonslip sections  23   a  can be held by fingertips. The handle  2  of the razor  1  is therefore easy to use. 
     The present embodiment may be modified as follows. 
     The back wall section  18  may be omitted from the wall  16 . In this case, the space  11  may be opened forward and backward inside the peripheral wall section  17 . 
     The space  11  may be omitted from the grip portion  3 . In this case, to allow the finger rest walls  20  to be elastically deformable, the section in the grip portion  3  that corresponds to the space  11  may be filled with flexible material such as cotton or sponge. 
     When the front section  8 , the back section  9 , and the side sections  10  do not need to be distinguished from one another, the finger rest walls  20  and the space  11  may be provided in at least one of the back section  9  and the side sections  10 , in addition to in the front section  8 . 
     The amount of displacement when the finger rest walls  20  are pressed and deformed may be greater in a middle portion of the finger rest walls  20  with respect to the thickness direction Z than in the remainder. 
     The steps  19   a  of the side walls  19  are heat welded to the end faces  13   a  of the side frame sections  13 . However, the steps  19   a  may be unstickable from the end face  13   a  of the side frame sections  13 . In this case, using, as an index, unsticking of the side walls  19  from the side frame sections  13  due to frequent use of the razor, the handle  2  can be replaced at an appropriate time. 
     The razor head  4  may be fixed to the handle  2 . Alternatively, the razor head  4  may be detachable from the handle  2 , so that the razor head  4  is replaceable. Further, the razor head  4  does not necessarily need to be supported swingable relative to the handle  2 . 
     Other than the razor  1 , the present invention may be applied to the handle of any type of bladed hand tool, such as a graver, a cutter, scissors, nail clippers, a kitchen knife, a medical instrument (such as, a surgical knife).