Abstract:
A reciprocating shaver including an inner cutter upwardly pushing spring for pressing the inner cutter against the inner surface of the outer cutter; slide members held on the outer cutter frame so as to be able to slide; outer cutter elastically supporting members which are for elastically supporting the outer cutter and mounted in the outer cutter frame with one end of each one of them engaging one of the slide members, and another end thereof engaging the outer cutter; and float setting members which are provided in the shaver main body and respectively engage the slide members, in linkage with the mounting motion of the outer cutter frame relative to the shaver main body, so as to determine the position of the slide members.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a reciprocating electric shaver for shaving face whiskers (“hair”) by causing an inner cutter to move reciprocally while being pressed against the inner surface of an outer cutter that is substantially inverted-U-shaped when viewed from the side. 
         [0003]    2. Description of the Related Art 
         [0004]    Reciprocating electric shavers are commonly known. Generally, reciprocating electric shavers are made so that an inner cutter is caused to move reciprocally while it is being pressed against the inner surface of an outer cutter that is substantially inverted-U-shaped when seen from the side, and hair coming through the slits provided in the outer cutter is cut by the reciprocating inner cutter. 
         [0005]    In the reciprocating electric shaver disclosed in Japanese Patent Application Laid-Open (Kokai) No. No. 2004-340838, an outer cutter is held so that it can slide freely up and down in an outer cutter frame secured to a shaver main body that contains a motor, and an inner cutter, which is urged upward by an inner cutter upwardly pushing spring, is caused to move reciprocally while being pressed against the inner surface of the outer cutter. More specifically, in this shaver, an oscillator is employed, and this oscillator is vibrated by the motor housed in the shaver main body; in addition, the inner cutter is provided on this oscillator so that it is capable of swinging and is urged upward by an inner cutter upwardly pushing spring. The inner cutter is moved reciprocally while being pressed against the inner surface of the outer cutter by a prescribed spring force. 
         [0006]    In this conventional shaver, the contact pressure of the outer cutter against the skin (hereinafter called the outer cutter float pressure) is set by the upward pushing force of the inner cutter, that is, by the spring force of the inner cutter upwardly pushing spring. Accordingly, the outer cutter, when contact is made against the skin with a force stronger than the spring force of the inner cutter upwardly pushing spring, will sink in (or descend) while compressing the inner cutter upwardly pushing spring. 
         [0007]    The ideal pressure (float pressure) when the outer cutter sinks in varies depending on the condition of the hair or skin of the user or on the preference of the user. In the above-described conventional shaver, it becomes necessary to change the spring force of the inner cutter upwardly pushing spring in order to change that float pressure. In order to weaken the outer cutter float pressure, for example, the inner cutter upwardly pushing spring may be made weaker. When that is done, however, the contact pressure between the inner cutter and the outer cutter will become weaker, and there will be a danger that the sharpness of the shave will deteriorate. In order to strengthen the outer cutter float pressure, conversely, the inner cutter upwardly pushing spring may be made stronger. When that is done, however, the contact pressure between the inner cutter and the outer cutter tends to become excessive, leading to such problems as the noise caused by sliding sounds becoming greater, or the temperature of the outer cutter surface rising due to the heat of friction. 
         [0008]    In view of the above situations, the inventor of the present application studied a structure of elastically supporting the outer cutter in the up and down direction relative to the outer cutter frame, for the purpose of being able to set the float pressure while optimally maintaining the contact pressure between the outer cutter and the inner cutter. It was found preferable that the outer cutter float pressure be adjustable from the shaver main body side. When, however, in such an adjustable structure, an outer cutter frame and shaver main body linking mechanism, that is, a mechanism for transmitting the movement of a manipulator on the shaver main body side to the float pressure adjustment mechanism on the outer cutter frame side, becomes necessary, and the structure as a result becomes complex. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    Accordingly, an object of the present invention, devised in view of the above-described circumstances, is to provide a reciprocating electric shaver in which, when provision is made so that the outer cutter float pressure is suitably set from the shaver main body side while optimally maintaining the contact pressure between the outer cutter and the inner cutter, a linking mechanism for transmitting the movement of the manipulator on the shaver main body side to the float pressure adjustment mechanism on the outer cutter frame side is made simple, and a provision that the float pressure is automatically set in linkage with the attachment and detachment of the outer cutter, so that outer cutter attachability-detachability and cleaning efficiency are enhanced. 
         [0010]    The above object is accomplished by a unique structure of the present invention for a reciprocating electric shaver that includes
       an outer cutter which is substantially inverted-U-shaped when viewed from the side and provided so as to slide up and down in an outer cutter frame that is detachably mounted on the main body of the shaver, and   an inner cutter which is reciprocated while being pressed upward from below against an inner surface of the outer cutter; and   in the present invention, the shaver further includes:
           an inner cutter upwardly pushing spring for pressing said inner cutter against the inner surface of said outer cutter;   slide members slidably provided on the outer cutter frame;   outer cutter elastically supporting members for elastically supporting said outer cutter, the outer cutter elastically supporting members being mounted on said outer cutter frame with one end of each one of the outer cutter elastically supporting members being engaged with one of said slide members and another end thereof being engaged with said outer cutter; and   float setting members provided in said shaver main body so that said float setting members are caused to engage said slide member, in linkage with a mounting motion of said outer cutter frame relative to said shaver main body, thus determining a position of said slide members.   
           seen from the above, in the present invention, the outer cutter elastically supporting members for elastically supporting the outer cutter is provided separately from the inner cutter upwardly pushing spring. Accordingly, the outer cutter float pressure can be varied by way of changing the spring force of the outer cutter elastically supporting members. If the spring force of the outer cutter elastically supporting members is oriented downward (toward the shaver main body), the outer cutter float pressure will be such that the difference (F(IN)−F(OUT)), which is between the spring force F(IN) of the inner cutter upwardly pushing spring and the spring force F(OUT) of the outer cutter elastically supporting members will be the outer cutter float pressure F(TOT), and the outer cutter float pressure F(TOT) will become smaller. Conversely, if the spring force of the outer cutter elastically supporting members is oriented upward, then the outer cutter float pressure F(TOT) will be the sum (F(IN)+F(OUT)) and will become larger.       
 
         [0019]    Moreover, in the present invention, in the shaver main body, float setting members are provided, and, in linkage with the outer cutter frame mounting motion relative to the shaver main body, the float setting members engage the slide members, determine the position of the slide members, and set the elastic support force of the outer cutter elastically supporting members. Thus, the structure is simple, and the shaver has an enhanced outer cutter attachability-detachability. As a consequence, outer cutter cleaning can be done easily, and cleaning efficiency is high. 
         [0020]    en the outer cutter elastically supporting members urge the outer cutters downward (toward the shaver main body), then the spring force F(OUT) is set smaller than the spring force F(IN) of the inner cutter upwardly pushing spring. In this setting, the outer cutter float pressure will be the difference shown by F(IN)−F(OUT) and will be weaker upward. 
         [0021]    The outer cutter elastically supporting members may urge the outer cutter upward. In this structure, the outer cutter float pressure will become a spring force that is a total of the spring force F(IN) of the inner cutter upwardly pushing spring and the spring force F(OUT) of the outer cutter elastically supporting members. As a consequence, the outer cutter float pressure can be made very large. 
         [0022]    The outer cutter elastically supporting members which push the outer cutter downward (toward the shaver main body) can be compression coil springs which are compressed and installed (or installed in a compressed manner) between the outer cutter and the outer cutter frame. Instead, pulling springs that pull the outer cutter down can be used in lieu of the compression coil spring. Further, the outer cutter elastically supporting member can be elastic bodies made of a synthetic resin. It is preferable that the outer cutter elastically supporting members be installed such that both ends of the outer cutter are supported with the same spring force. In that case, the spring force is a total value of the spring forces of the outer cutter elastically supporting members at the two (right and left) ends of the outer cutter. 
         [0023]    In the present invention, an adjustment mechanism for adjusting the spring force of the outer cutter elastically supporting member can be obtained by, for example, such a structure that the slide member are provided so as to be movable up and down relative to the outer cutter frame, and compression coil that constitute the outer cutter elastically supporting members are provided so that the upper ends thereof are in contact with one of the slide members and the lower ends thereof are in contact with the outer cutter, thus urging the outer cutter downward (toward the shaver main body). 
         [0024]    In the present invention, further, it is possible to set the height of the slide members by the float setting members provided in the shaver main body. This can be done by such a structure that slide member downward pushing spring, which are stronger than the compression coil springs that constitute the outer cutter elastically supporting members, are compressed and installed between each of the slide members and the outer cutter frame so that the slide members are being provided with a downward return force, and then each of the slide members is butted against the float setting members provided in the shaver main body, thus fixing the height thereof. 
         [0025]    Furthermore, the height of the float setting members is made changeable by a manual manipulator provided in the shaver main body, and this makes it possible that the slide member height can be changed with such a manual manipulator. Thus, in the present invention, it is possible to easily adjust the outer cutter float pressure by changing the spring force of the outer cutter elastically supporting members. For the manual manipulator, one that is manipulated from the outside of the shaver main body has a better manipulability and is preferable. Nevertheless, the manipulator can be provided in an opening of the upper portion of the shaver main body that appears when the outer cutter is removed. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0026]      FIG. 1  is an external perspective view of a reciprocating shaver according to one embodiment of the present invention; 
           [0027]      FIG. 2  is a vertical section of the shaver head unit thereof; 
           [0028]      FIGS. 3A and 3B  are enlarged views, in cross section, of a part of the shaver head unit of  FIG. 2 ; 
           [0029]      FIG. 4  is an exploded perspective view of the shaver head unit; 
           [0030]      FIG. 5  is a side elevation of an adjustment mechanism for a float setting member; 
           [0031]      FIG. 6  is a bottom view of the same; and 
           [0032]      FIG. 7  is a rear view of the same. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]      FIG. 1  is a perspective view of the reciprocating shaver according to one embodiment of the present invention, while  FIG. 2  is a vertical section of the shaver head unit of this shaver. In  FIG. 2 , a condition in which the outer cutter float pressure is made either strong or ordinary (normal) is illustrated on the left half of the drawing, and a condition in which the outer cutter float pressure is made weak (soft) is illustrated on the right half of the drawing.  FIG. 3A , a partial view of  FIG. 2 , shows the situation in which the outer cutter float pressure is made strong (normal), and  FIG. 3B , another partial view of  FIG. 2 , shows the situation in which the outer cutter float pressure is made weak (i.e. soft, corresponding to the right half of  FIG. 2 ).  FIG. 4  shows the shaver head unit disassembled, and  FIG. 5  shows the detail of a mechanism for adjusting the height of a slide member by a manual manipulator.  FIG. 6  is a bottom view of the slide member height adjusting mechanism and  FIG. 7  is a rear view thereof. 
         [0034]    In  FIG. 1 , the reference numeral  10  is a main body of the shaver of the present invention, and this shaver main body  10  houses therein a battery, an electric motor, a control circuitry and other required shaver components (not shown in  FIG. 1 ). An outer cutter assembly  12  is detachably attached from above to the upper end of the shaver main body  10 . The outer cutter assembly  12  includes three outer cutters  16   a ,  16   b  and  16   c  (shown by “ 16   a  to  16   c ” or merely by “ 16 ” in the description below) that are installed in parallel inside a head cover  14  (see  FIG. 2 ) and so as to make up and down motions. In the head cover  14 , four first engagement pawls  18  (see  FIG. 3B ) are provided to protrude downward, while shaver head attachment-detachment buttons (“shaver head buttons”)  20  imparted with a tendency to return so as to protrude to the outside are mounted on the left and right side surfaces of the shaver main body  10 . Second engagement pawls (not shown) formed in the shaver head buttons  20  are provided so as to be engaged with and disengaged from the first engagement pawls  18 . 
         [0035]    The head cover  14  covers the upper surface (upper end) of the shaver main body  10  except a part on its front side, so that that part of the upper portion of the shaver main body  10  on the front side is exposed. That exposed portion accommodates a fine shaving blade  22 . More specifically, the fine shaving blade  22  is provided to protrude upward by a manipulator  24  provided in the shaver main body  10 . When using the fine shaving blade  22 , the manipulator  24  is pushed upward to make the fine shaving blade  22  protrude upward. In  FIG. 1 , the fine shaving blade  22  is retracted in the shaver main body  10 . The reference numeral  26  in  FIG. 1  is an electrical power switch. When the electrical power switch is pressed once, the motor in the shaver main body  10  starts running, and when it is pressed once more, the motor stops. 
         [0036]    In  FIG. 2 , the reference numeral  28  is an inner block secured on the inside of the upper part of the shaver main body  10 , while  30  is an oscillator mounted in an opening in the inside block  28 . The left and right edges of the oscillator  30  are secured by screws  34 , through U-shaped flexible connectors  32 . In the lower center surface of the oscillator  30 , an elongated channel  36  is formed, long in the direction perpendicular to the drawing surface of  FIG. 2 . Into this long channel  36 , a vibrating shaft  38  which moves eccentrically by the rotational power of the motor is engaged. As a consequence, when the motor runs, the oscillator  30  vibrates to the left and right in  FIG. 2 . 
         [0037]    An inner cutter holder  40  protrudes out at the center of the upper surface of the oscillator  30 , and a vertical shaft  42  is secured to the inner cutter holder  40 . In this vertical shaft  42 , a slider  44  is provided so that it can freely slide up and down. A coil spring  46  is compressed and installed (or installed in a compressed manner) between the slider  44  and the inner cutter holder  40  of the oscillator  30 , so that a tendency to return upward is imparted to the slider  44 . The coil spring  46 , as will be described in detail below, is a spring that will constitute an inner cutter upwardly pushing spring in the present invention. The slider  44 , moreover, is prevented from sliding completely off the vertical shaft  42  by a stopper  48  provided at the upper end of the vertical shaft  42 . 
         [0038]    The reference numeral  50  refers to inner cutters that respectively slide against the inner surfaces of the three outer cutters  16 . The inner cutters  50  are provided so that they can swing left and right by the slider  44  and are capable of being oscillated sideways (left and right) by the oscillator  30 . Though three inner cutters  50 , respectively corresponding to the three outer cutters  16   a  to  16   c , are provided, only one is shown in  FIGS. 2 ,  3 A and  3 B. Also, a sealing member  52  is installed between the upper surface of the inside block  28  and the inner cutter holder  40  of the oscillator  30  to prevent water from coming into the shaver main body  10 . 
         [0039]    Next, the outer cutter assembly  12  will be described. 
         [0040]    The outer cutter assembly  12 , as illustrated in  FIG. 4 , has three outer cutters  16   a ,  16   b  and  16   c  installed in an outer cutter frame  54  so that they can move up and down, and the outer circumference thereof is enclosed by the head cover  14  ( FIGS. 1 and 2 ). The outer cutter frame  54 , when the head cover  14  is secured to the shaver main body  10 , is held and secured between the head cover  14  and the shaver main body  10 . 
         [0041]    At either end of the outer cutters  16   a  to  16   c , spring loading chambers  58  are provided for respectively loading therein outer cutter downward pushing springs  56  which constitute outer cutter elastically supporting members in the present invention. These spring loading chambers  58  are guided by guides  60  projecting from the inner surfaces of two end plates  54   a  of the outer cutter frame  54 , making it possible for the outer cutters  16   a  to  16   c  to move up and down. On the outer surface of each one of the two end plates  54   a  of the outer cutter frame  54 , a slide member  62  is attached so that it can freely move up and down. More specifically, two engagement pawls  64  are formed to project from the each one of the outer surfaces of the end plates  54   a  of the outer cutter frame  54 , and these engagement pawls  64  are brought to be engaged with long vertical slits  66  formed in the respective slide members  62 . 
         [0042]    On the upper edge of each one of the slide members  62 , three horizontal projections  68  are formed (inwardly) that pass through the long vertical openings formed in each end plate  54   a  of the outer cutter frame  54  and advance horizontally into the spring loading chambers  58  for the outer cutters  16 . These horizontal projections  68  engage with the upper ends of the outer cutter downward pushing springs  56  provided in the spring loading chambers  58  for the outer cutters  16 . More specifically, the outer cutter downward pushing springs  56  are compressed in such a condition that the lower ends thereof are in contact with (or engaged with) the bottom surfaces of the spring loading chambers  58  while the upper ends thereof are in contact with (or engaged with) the horizontal projections  68  of the slide members  62 . 
         [0043]    A downward oriented return force is imparted to the slide members  62  by slide member downward pushing springs  70  which are compressed and installed between the outer cutter frame  54  and the slide members  62 . More specifically, the lower end of each of the springs  70  is latched by a projection  72  formed at the center of the lower edge of each one of the slide members  62 , while the upper end of the spring  70  is latched by a projection  74  formed at the center of the upper edge of each one of the end plates  54   a  of the outer cutter frame  54 . These springs  70  exhibit a return force that is stronger than the combined spring forces of the downward pushing springs  56  for the three outer cutters. As a consequence, the slide members  62 , while being subjected to an upward counterforce by the outer cutter downward pushing springs  56 , are also subjected to a downward counterforce by these slide member downward pushing springs  70 . Because the downward counterforce of the slide member downward pushing springs  70  is larger than the upward counterforce of the outer cutter downward pushing springs  56 , the slide members  62  can stay at the descended positions. 
         [0044]    More specifically, the slide members  62  stabilize at positions where the engagement pawls  64  of the end plates  54   a  of the outer cutter frame  54  are butted against the upper edges of the slits  66  of the slide members  62 . This situation is shown in the left half of  FIG. 2 , in  FIG. 3A , and in  FIGS. 5 and 7 . In this situation, the outer cutter downward pushing springs  56  are in the extended state; as a result, the force (F(OUT)) pushing the outer cutters  16   a  to  16   c  down is small. Accordingly, the difference from the upward pushing force (F(IN)) of the inner cutter upwardly pushing spring  46 , the difference being F(TOT)=F(IN)−F(OUT), will become greater. 
         [0045]    The height level of the slide members  62  is set by float setting members  76  provided in the shaver main body  10 . As shown in  FIGS. 4 and 6 , the float setting members  76  are formed so that they rise upward from both ends of a horizontal plate  78  that is provided inside the back surface (wall) of the shaver main body  10  so as to be movable vertically or up and down. These float setting members  76  advance out and upward through vertical grooves formed in the shaver head buttons  20  so as to face the lower surfaces of the center of the lower edges of the slide members  62  (the lower surfaces of the projections  72 ). As a result, when the outer cutter assembly  12  is attached to the shaver main body  10  and locked to the shaver head buttons  20 , the lower edges of the slide members  62  contact the upper edges of the float setting members  76 , and the height of the float setting members  76  is thus fixed as shown in, for instance,  FIGS. 3A and 3B   
         [0046]    A cam plate  80  formed with a diagonal cam channel  82  is secured to the horizontal plate  78 . The diagonal cam channel  82  of the cam plate  80  is engaged to a projection  86  of a manual manipulator  84  that is mounted on the back surface of the shaver main body  10  so that it can slide horizontally. As a result, when the manual manipulator  84  is moved left and right as shown by arrows in  FIG. 7 , the cam plate  80  and the horizontal plate  78  are moved up and down due to the diagonal cam channel  82 , and as a result the float setting members  76  are moved up and down. 
         [0047]    When the manual manipulator  84  is moved to one side (for example to the left in  FIG. 7 ), the float setting members  76  ascend. As a result, the slide members  62  are ascended, and the outer cutter downward pushing springs  56  extend. Accordingly, the spring force F(OUT) of the outer cutter downward pushing springs  56  becomes smaller, and the float pressure F on the outer cutters  16 , which is F(TOT)=T(IN)−F(OUT), becomes larger, thus bringing a normal condition. When, conversely, the manual manipulator  84  is moved to the other side (to the right in  FIG. 7 ), then the slide members  62  are descended, and the outer cutter downward pushing springs  56  are compressed and contract. Accordingly, the spring force F(OUT) on the outer cutter downward pushing springs  56  become larger, and the float pressure F(TOT) on the outer cutters  16  becomes smaller, so that a soft condition is brought, and the outer cutters  16  are moved up and down smoothly, nicely following the curved surfaces of the skin. 
         [0048]    In the above-described embodiment, the outer cutter downward pushing springs  56  are the outer cutter elastically supporting members. However, in the present invention, the outer cutter elastically supporting members can be elastic bodies made of a synthetic resin and not a spring.