Patent Publication Number: US-2023150156-A1

Title: Shaver

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the National Stage filing under 35 U.S.C. 371 of International Application No. PCT/KR2016/013432, filed on Nov. 21, 2016, which claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2016-0154730, filed on Nov. 21, 2016, the contents of which are all hereby incorporated by reference herein in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a razor including a blade housing with blades for body/facial hair cutting installed in such a way to allow an automatic linear movement in the direction of the body/facial hairs being cut, thereby increasing the cutting efficiency, and to allow pivoting of the cartridge, thereby enhancing the user&#39;s shaving comfort. 
     BACKGROUND 
     A razor generally includes a handle that can be grasped by the user, and a cartridge capable of cutting the body hair. 
     Related art includes a razor capable of providing a vibration force to the razor cartridge in the upward and downward for providing compression/distension motion for cutting the body/facial hairs. However, the prior art lacks razor configurations which provide pivoting of the cartridge or linear movement in the direction of the body/facial hairs being cut, and thus have reduced cutting efficiency and provide reduced shaving comfort. The problems of the related art are not limited to those mentioned above, and other unmentioned problems can be clearly understood by those skilled in the art. 
     The present disclosure seeks to provide a razor, in particular, a razor including therein a blade housing with blades for body/facial hair cutting installed in such a way to allow an automatic linear movement in the direction of the body/facial hairs being cut, thereby increasing the cutting efficiency, and to allow pivoting of the cartridge, thereby enhancing the user&#39;s shaving comfort. 
     SUMMARY 
     According to at least one embodiment of the present disclosure, a razor includes a handle configured to be gripped by a user, a power generation unit disposed in the handle and configured to provide rotational power, a drive transmission unit coupled to the power generation unit and configured to be rotated by the rotational power, a cartridge including a blade housing on which one or more blades are seated, and a drive receiving unit formed at one side of the cartridge and configured to be in contact with the drive transmission unit to cause the blade housing to perform a linear movement in response to rotation of the drive transmission unit, wherein the cartridge is coupled to the handle such that the cartridge is pivotable about a pivot axis perpendicular to a rotational axis of the power generation unit, and wherein the pivot axis intersects the drive transmission unit. 
     The cartridge may further include a guide member configured to guide the linear movement of the blade housing. 
     In addition, the razor may further include a rail at each side of the guide member, and a slider bar at each corresponding side of the blade housing, wherein the guide member guides the linear movement of the blade housing as the slide bars move along the rails. 
     One end of each slide bar may have a chamfer shape for reducing an area of contact with a corresponding rail. 
     The drive transmission unit may include an eccentric cam head having at least a partially curved surface. 
     The cartridge may further include a cartridge connector configured to couple the guide member to the handle and to provide the pivot axis for the cartridge to pivot. 
     The cartridge connector may further include a restoration unit configured to restore the cartridge to an initial state when the cartridge is pivoted about the pivot axis. 
     The restoration unit has elasticity, and it may be in contact with the rear of the guide member. 
     The cartridge connector may include a boss protruding outwardly from each side thereof, and the guide member may include boss grooves each configured to engage a corresponding boss of the cartridge connector. 
     Further, the pivot axis is aligned with the bosses engaged with the boss grooves. 
     The drive receiving unit may include an upper receiving section and a lower receiving section which protrude toward the rear of the blade housing wherein the upper receiving section and the lower receiving section are parallel and spaced apart by a predetermined distance. 
     The upper receiving section and the lower receiving section define a space therebetween in which the drive transmission unit is inserted. 
     The drive transmission unit is configured to rotate and push up the upper receiving section or push down the lower receiving section to allow the blade housing to carry out the linear movement. 
     The cartridge is configured to have, in an initial state, an angle generated by a skin-contact surface of the cartridge and the rotational axis is in a range of about 30° to 60°. 
     According to at least one embodiment of the present disclosure, a razor includes a handle, a power generation unit disposed in the handle, a cartridge including a blade housing on which one or more blades are seated, a drive receiving unit formed at one side of the cartridge, and a drive transmission unit configured to transmit power generated by the power generation unit to the drive receiving unit, causing the drive receiving unit to move such that the blade housing performs a linear movement, wherein the cartridge is pivotably coupled to the handle about a pivot axis parallel to a longitudinal direction of the one or more blades, and wherein the pivot axis intersects the drive transmission unit. 
     Other specific details of the present disclosure are included in the detailed description and drawings. 
     Advantageous Effects 
     The embodiments of the present disclosure have the following effects. 
     A blade housing with blades installed for cutting the body/facial hair performs an automatic linear movement in the direction of the body/facial hair being cut. Thus, the speed at which the blade housing performs the automatic linear movement is added to the speed at which the user carries out the manual body/facial hair cutting operation, allowing the body/facial hair cutting operation to be shortened, thereby increasing the body/facial hair cutting efficiency. 
     In the razor of embodiments, the cartridge, which is capable of being pivoted when the user performs the body/facial hair cutting operation, follows along the skin-contact face in a natural pivoting movement, enhancing the user&#39;s shaving comfort. 
     The effects according to the present disclosure are not limited by the contents exemplified above, and more various effects are included in the specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a razor according to at least one embodiment of the present disclosure. 
         FIG.  2    is an exploded perspective view of a cartridge and a power unit ( 30 ) according to at least one embodiment of the present disclosure. 
         FIG.  3    is a rear perspective view of a blade housing according to at least one embodiment of the present disclosure. 
         FIG.  4    is an exploded perspective view of a blade housing and a guide member according to at least one embodiment of the present disclosure. 
         FIG.  5    is a front view of a cartridge according to at least one embodiment of the present disclosure. 
         FIG.  6    is a side perspective view of an eccentric cam according to at least one embodiment of the present disclosure. 
         FIG.  7    is a side view of a blade housing and an eccentric cam as coupled together according to at least one embodiment of the present disclosure. 
         FIGS.  8  to  10    are schematic views showing the movement of an eccentric cam receptacle according to the rotational motion of an eccentric cam head according to at least one embodiment of the present disclosure. 
         FIGS.  11  to  13    are side cross-sectional views taken along line L-L′ in  FIG.  4   , showing the change of a cartridge according to at least one embodiment of the present disclosure, when the blade housing linearly moves with respect to a guide member according to the movement of the eccentric cam receptacle shown in  FIGS.  8  to  10   . 
         FIGS.  14  to  16    are partial side cross-sectional views of a razor, showing the change of a cartridge according to another embodiment of the present disclosure, when a blade housing linearly moves with respect to a guide member according to the movement of the eccentric cam receptacle shown in  FIGS.  8  to  10   . 
         FIG.  17    is a rear perspective view of a blade housing according to yet another embodiment of the present disclosure. 
         FIG.  18    is a side view of a cartridge being positioned in the initial state according to at least one embodiment of the present disclosure, when an eccentric cam head is at the lowermost position. 
         FIG.  19    is a side view of the cartridge shown in  FIG.  18   , after being pivoted. 
         FIG.  20    is a side view of the cartridge shown in  FIG.  18    without a guide member and a cartridge connector. 
         FIG.  21    is a side view of a blade housing shown in  FIG.  20   , after being pivoted. 
         FIG.  22    is a side view of a cartridge being subjected to a torque T 2  generated by the drive of a motor, when an angle θ is an acute angle between a skin-contact face SF of the cartridge  10  and a rotational axis MA of the motor. 
         FIG.  23    is a side view of a cartridge being subjected to torque T 2  generated by the drive of a motor, when angle θ is an obtuse angle between skin-contact face SF of the cartridge and rotational axis MA of the motor. 
         FIG.  24    is a side view of a cartridge not being subjected to torque T 2  generated by the drive of a motor, when angle θ is a right angle between skin-contact face SF of the cartridge and rotational axis MA of the motor. 
         FIG.  25    is an enlarged, partial view of a region R shown in  FIG.  22   . 
         FIG.  26    is a cross-sectional side view of a cartridge according to at least one embodiment of the present disclosure, taken along line K-K′ in  FIG.  4   . 
         FIG.  27    is a cross-sectional side view of a cartridge connector coupled to the cartridge shown in  FIG.  26   . 
         FIG.  28    is a schematic view of a hair cutting process using a conventional razor. 
         FIG.  29    is a schematic view of a hair cutting process using a razor according to some embodiments of the present disclosure. 
         FIG.  30    is a photograph taken by a scanning electron microscope (SEM) showing a section of a hair cut using a conventional razor. 
         FIG.  31    is a photograph taken by the SEM showing a section of a hair cut using a razor according to some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The advantages and features of the present disclosure and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and to fully disclose the scope of the disclosure to those skilled in the art. The disclosure is only defined by the scope of the claims. Like reference numerals designate like elements throughout the specification. 
     Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this disclosure belongs. In addition, commonly used dictionary defined terms are not ideally or excessively interpreted unless explicitly defined otherwise. 
     The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present disclosure. In the present specification, a singular form of nouns includes their plural forms unless otherwise specified in the specification. Throughout this specification, when a part “comprises” and/or is “comprising” an element, present disclosure does not exclude the presence or addition of one or more other elements in addition to the stated element. 
     Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. 
       FIG.  1    is a perspective view of a razor  1  according to at least one embodiment of the present disclosure. 
     As shown in  FIG.  1   , the razor  1  according to at least one embodiment includes a handle  20  coupled to a cartridge  10  having a plurality of blades  111  for cutting body/facial hairs. 
     The handle  20  is a portion to be gripped by a user. The user can cut the body/facial hairs by hand-holding the handle  20 , bringing one side of the cartridge  10  into contact with the part where the body/facial hairs are to be cut, and then applying a wrist snapping action or changing the grip of the handle  20 . Generally, the razor  1  is used for cutting a male&#39;s beard while washing the face, and for cutting a leg hair or the like for a female. Cutting the hairs is often done in a washroom, and thus, it is common that the handle  20  is grasped by the user&#39;s wet hand, or the moisture level in the washroom is very high. Therefore, it is preferable that the handle  20  is made of a grippy material comfortable for the user, for example, synthetic rubber, plastic or the like, which does not readily corrode even if it is frequently in contact with moisture. However, the handle  20  is not limited thereto, and can be made of various other materials. 
     The cartridge  10  includes a blade housing  11  and a guide member  12 . The cartridge  10  and the handle  20  are connected via a cartridge connector  40 . 
     The handle  20  is mounted internally with a power unit  30 . The power unit  30  contacts the blade housing  11  of the cartridge  10  and generates power to cause the blade housing  11  to move linearly. Details of the cartridge  10  and the power unit  30  will be described later. 
       FIG.  2    is an exploded perspective view of a cartridge  10  and a power unit  30  according to at least one embodiment of the present disclosure. 
     As shown in  FIG.  2   , the cartridge  10  is in contact with the power unit  30 . As described above, the cartridge  10  includes the blade housing  11  and the guide member  12 . The blade housing  11  is installed with a plurality of blades  111  for cutting the body/facial hairs, and is linearly moved by receiving power. The guide member  12 , which houses blade housing  11  and frame  112  as shown in  FIG.  2    and the various figures, guides the blade housing  11  so as to smoothly perform a linear movement. 
     The cartridge connector  40  connects the guide member  12  and the handle  20 , and provides a pivot axis PA for the cartridge  10  to pivot. Hereinafter,  FIG.  3    to  FIG.  6    will be described with reference to  FIG.  2   . 
       FIG.  3    is a rear perspective view of a blade housing  11  according to at least one embodiment of the present disclosure. 
     As shown in  FIG.  2    and  FIG.  3   , the blade housing  11  includes a plurality of blades  111  for cutting the body/facial hairs, and a frame  112  for supporting the plurality of blades  111 . 
     The frame  112  has a substantially rectangular structure opening to the front and to the rear. A vertical up and down direction of the cartridge  10  refers to the longitudinal direction of frame sides  112   a  and  112   b  extending a shorter length of the cartridge  10 , and a lateral direction of the cartridge  10  refers to the longitudinal direction of the long frame sides  112   c  and  112   d  extending a greater length of the cartridge  10 . The longitudinal direction means the direction of the longest element among the height, length, and width. When the frame sides are connected to each other, a substantially rectangular face is formed having edges of the frame  112 . The front-rear direction of the cartridge  10  refers to a normal direction perpendicular to the rectangularly formed face. 
     As shown in  FIG.  2   , the left-right axis of the cartridge  10  are defined as an X axis, the vertical axis as a Y axis, and the front-rear axis as a Z axis. The left direction is defined as the X-axis direction, the right direction as the negative X-axis direction, the upward direction as the Y-axis direction, the downward direction as the negative Y-axis direction, the front direction as the Z-axis direction, and the rear direction as the negative Z-axis direction. Here, the X, Y, and Z axes take the cartridge  10 , not an eccentric cam  31 , as a reference. In describing directions of the eccentric cam  31 , the reference is based on the direction shown in the drawing. 
     In the present specification, the X, Y, and Z axes are defined as above, and the present disclosure will be described below with reference to the X, Y, and Z axes defined above. However, the X, Y, and Z axes defined above are merely for convenience of description of the present disclosure, and do not limit the scope of the present disclosure. 
     Specifically, the frame  112  has the first frame side  112   a  and the second frame side  112   b , each of which is relatively short in length, and which are formed on the right and left sides, respectively. The frame  112  also has a lower frame side  112   d  which is relatively long and connects the first frame side  112   a  and the second frame side  112   b  at their lower ends, and an upper frame side  112   c  which is relatively long and connects the first frame side  112   a  and the second frame side  112   b  at their upper ends. 
     The plurality of blades  111  is installed so that each blade  111  has its edge exposed on the front surface of the frame  112  with both ends thereof being supported by the first frame side  112   a  and the second frame side  112   b . As shown in  FIGS.  2  and  3   , the plurality of blades  111  may be fixed to the first frame side  112   a  and the second frame side  112   b  by clips  116  formed to penetrate or envelope the first frame side  112   a  and the second frame side  112   b , or penetrate one of the first frame side  112   a  and the second frame side  112   b  and envelope the other. In addition, other types of fastening devices than the clip  116  may be used to fasten the plurality of blades  111 . The blades  111  may be disposed parallel to each other and parallel to the upper frame side  112   c  and the lower frame side  112   d . The edges of the plurality of blades  111  are bent at a predetermined angle with respect to the forward direction, i.e., the Z-axis direction of the blade housing  11 . Particularly, the edge is advantageously bent downward with respect to the forward direction of the blade housing  11 , i.e., toward the negative Y-axis direction so as to facilitate cutting of the body/facial hairs. However, the present disclosure is not limited to this, and the blade  111  may be a steel strip blade or a flat blade. Here, the steel strip blade is a kind of the blade  111  provided with a blade member welded to the upper surface of a bent support body. The flat blade is a unitary type of the blade  111  formed to be flat without being bent or curved. 
     On the rear surface of the blade housing  11 , a drive receiving unit capable of contacting the power unit  30  is formed. In this embodiment, an eccentric cam receptacle  113  is used as an example of the drive receiving unit. The eccentric cam receptacle  113  includes an upper receiving section  113   a  and a lower receiving section  113   b . As shown in  FIGS.  2  and  3   , the upper receiving section  113   a  and the lower receiving section  113   b  of the eccentric cam receptacle  113  are attached to substantially the center of the lower frame side  112   d  of the blade housing  11 , protruding rearward of the blade housing  11 , i.e., in the negative Z-axis direction. The upper receiving section  113   a  and the lower receiving section  113   b  are formed to be spaced apart from each other by a predetermined distance and are formed to be parallel to the upper frame side  112   c  and the lower frame side  112   d . Therefore, the upper receiving section  113   a , the lower frame side  112   d  of the blade housing  11 , and the lower receiving section  113   b  have a substantially ‘E’ symbol shape. The upper receiving section  113   a  and the lower receiving section  113   b  may have a substantially rectangular shape, but are not limited thereto and may have various shapes. Power is transmitted to the eccentric cam receptacle  113  according to the operation of the power unit  30 , so that the blade housing  11  moves linearly, and a detailed description thereof will be provided below. 
     Protruding from both outer side surfaces of the first and second frame sides  112   a  and  112   b  of the blade housing  11  are slide bars  114  formed to be guided by the guide member  12 . According to at least one embodiment of the present disclosure, the slide bars  114  are linearly elongated in the Y-axis direction and the negative Y-axis direction. However, when the blade housing  11  is configured to move in a different direction, the slide bars  114  may be made to extend along a straight line in another direction. Further, when the blade housing  11  is configured to have a curvilinear motion rather than a linear motion, the slide bar  114  may be formed corresponding to the curvilinear motion of the blade housing  11 , and in other various ways, it may be modified adaptively. The slide bar  114  may be formed on each of the outer side surfaces of the first and second frame sides  112   a  and  112   b , or one or more of the slide bar  114  may be formed on each of the outer side surfaces of the first and second frame sides  112   a  and  112   b . Alternatively, the number of the slide bars  114  formed in the first frame side  112   a  may be different from that of the slide bars  114  formed in the second frame side  112   b .  FIG.  4    is an exploded perspective view of the blade housing  11  and the guide member  12  according to at least one embodiment, and  FIG.  5    is a front view of the cartridge  10  according to at least one embodiment of the present disclosure. 
     The guide member  12  guides the blade housing  11  to facilitate the linear movement. On each of inner side surfaces of the guide member  12 , a rail  121  is formed so as to be able to engage with a corresponding slide bar  114  formed on a corresponding one of outer side surfaces of the blade housing  11 . The rail  121  is formed in a straight line extending in the Y-axis direction and the negative Y-axis direction to correspond to the slide bar  114 . The slide bar  114  has a generally rectangular parallelepiped shape elongated in the Y-axis direction. In some embodiments, the slide bar  114  may be chamfered at one end to have an acute angle or a curved surface in order to facilitate the engagement with the rail  121 , and after the engagement, to reduce the contact area between the slide bar  114  and the rail  121  in order to reduce frictional force therebetween. Then, the slide bar  114  is slidingly engaged with the rail  121  so that the blade housing  11  is linearly reciprocated with respect to the guide member  12  in the Y-axis direction and the negative Y-axis direction in which the rails  121  are formed. 
     According to at least one embodiment of the present disclosure, the rails  121  extend along a straight line in the Y-axis direction and the negative Y-axis direction, but the present disclosure is not limited thereto. Depending on the configured direction of movement of the blade housing  11 , the rails  121  may be formed in a straight line in another direction. Further, when the blade housing  11  is configured to perform a curved movement, rather than a linear movement, the rails  121  may be formed to correspond to the curved movement of the blade housing  11 , and in other various ways, they may be modified adaptively. The rails  121  may be modified as long as they have an engaging formation with the slide bar  114  by conforming the rails  121  to the width and the orientation of the slide bar  114 . In other words, the manner in which the blade housing  11  moves depends on the orientation of the formation of the slide bar  114  and the rail  121 . However, at least one embodiment of the present disclosure, as described above, prefers that the blade housing  11  linearly reciprocates in the Y-axis direction and the negative Y-axis direction, and hereinafter, the slide bar  114  and the rails  121  will be described as being elongated in the Y-axis direction and in the negative Y-axis direction. 
     As shown in  FIGS.  2  and  4   , the slide bars  114  are shaped to protrude outward from both outer side surfaces of the blade housing  11 , and the rails  121  are recessed inwardly at both inner side surfaces of the guide member  12 . When the slide bar  114  and the rail  121 , which have corresponding widths therebetween, are coupled together, the blade housing  11  is fixed with respect to the X-axis direction of the guide member  12 , and is allowed to reciprocate exclusively in the Y-axis direction of the guide member  12 , although the present disclosure is not limited thereto. For example, the slide bars  114  may be formed on both inner side surfaces of the guide member  12 , and the rails  121  may be formed on both outer side surfaces of the blade housing  11 , or the slide bars  114  and the rails  121  may be formed at various other positions. 
     The front side of the guide member  12  is open to facilitate engagement with the blade housing  11 . Once the blade housing  11  and the guide member  12  are engaged, the blade housing  11  is accommodated in the inner space of the guide member  12 , as shown in  FIG.  5   . The guide member  12  has a rubber guard  122  protruding from its lower portion toward the Z-axis direction, so that when the blade housing  11  is positioned at the lowermost position in the negative Y-axis direction with respect to the guide member  12 , the lower frame side  112   d  of the blade housing  11  is positioned closest to the rubber guard  122 . At this time, at the front surface of the cartridge  10 , there should be no or very minute step formed between the blade housing  11  and the guide member  12 . If a minute step is formed, it may be due to inadvertent occurrence during the manufacturing process or may be intentionally induced for user&#39;s convenience. 
     Therefore, the length, height, and width of the inner space of the guide member  12  accommodating the blade housing  11  may be formed to respectively correspond to the length, height, and width of the blade housing  11 . The length and width of the inner space of the guide member  12  may be less than the length and width of the blade housing  11  by an offset amount so that the blade housing  11  can smoothly slide relative to the guide member  12 . Further, as shown in  FIG.  5   , it is preferable that the height of the inner space of the guide member  12  be twice the amplitude of the blade housing  11  when the blade housing  11  performs the sliding reciprocating movement in the Y-axis direction. 
     As shown in  FIG.  5   , the blade housing  11  may be provided on its front surface with a comb guard  115 , and provided on the lower portion of the guide member  12  with the rubber guard  122 . 
     The comb guard  115  is disposed above the blades  111 , as shown in  FIG.  5   , to assist lubricant application by a lubrication band  13 . In some embodiment, the comb guard  115  is disposed below the blades  111 , which can align the body/facial hairs that enter the plurality of blades  111 . In other words, the comb guard  115  is not confined to a specific position, but may be disposed at various positions according to the functions to be performed. 
     The rubber guard  122  pulls the skin in contact with the cartridge  10  to guide the plurality of blades  111  to effectively cut the body/facial hairs. 
     The lubrication band  13  expands upon contact with water and provides a water-soluble material including a lubricating component, a soothing component, and the like. This supplies a lubricating component and a soothing component to the skin contacting the cartridge  10  during the shaving process, allowing the cartridge  10  to proceed smoothly while in contact with the skin surface and to sooth the skin. 
     As shown in  FIG.  5   , an opening  124  may be formed between the blades  111  and the rubber guard  122  on the guide member  12 . The opening  124  enhances the shaving performance by causing a part of the skin to convex, thus inducing the body/facial hairs to be cut in upright posture. 
     Heretofore, the comb guard  115  is provided in the blade housing  11  and the rubber guard  122  is provided in the guide member  12  as described referring to  FIG.  5   . The lubrication band  13  is not specified positionally between the blade housing  11  and the guide member  12 . However, the present disclosure is not limited to the above description, but may encompass different configurations. The comb guard  115  may be provided on the upper side, the lower side, or both the upper and lower sides of the guide member  12 . The rubber guard  122  may be provided on the blade housing  11 . The lubrication band  13  may be provided on the upper side, the lower side, or both the upper and lower sides of the blade housing  11  or of the guide member  12 . 
       FIG.  6    is a side perspective view of an eccentric cam  31  according to at least one embodiment. 
     As described above, a power unit  30  is mounted within the handle  20 . The power unit  30  contacts the blade housing  11  and generates power to cause the blade housing  11  to perform a linear movement. As shown in  FIG.  2   , the power unit  30  includes a power generator that receives electric power from an external source and generates a rotational power. This embodiment utilizes the motor  32  as one of various forms of the power generator. However, the power generator may include various devices capable of generating repetitive motions such as solenoids that perform linear motion in addition to the motor  32  that performs rotational motions. 
     The power unit  30  further includes a drive transmission unit for transmitting the power received from the motor  32 . In this embodiment, the eccentric cam  31  is used as an example of the drive transmission unit. Therefore, in the present embodiment, the power unit  30  also includes the eccentric cam  31  which is rotated by the power received from the motor  32 , and whose rotational axis MA is eccentrically formed. The drive transmission unit transmits the power generated by the rotational or linear motion transmitted from the power generator to a drive receiving unit to be described later so that the drive receiving unit can perform a linear motion. The eccentric cam  31  is merely an example in the present disclosure, and other configurations may be possible as long as they serve the same purpose of the eccentric cam  31 . 
     The eccentric cam  31  includes an eccentric cam head  311 , an eccentric cam body  313  and an eccentric cam neck  312 . The eccentric cam head  311  is directly engaged with the blade housing  11  to linearly move the same. The eccentric cam body  313  rotates the eccentric cam head  311  with the drive received from the motor  32 , and renders rotational axis MA of the eccentric cam head  311  to be eccentric. The eccentric cam neck  312  interconnects the eccentric cam head  311  and the eccentric cam body  313 . The motor  32 , eccentric cam body  313 , eccentric cam neck  312  and eccentric cam head  311  are sequentially connected to allow the rotation of the motor  32  by its shaft  321  to rotate the eccentric cam body  313  in unison with the eccentric cam neck  312  and the eccentric cam head  311  about the rotational axis MA of the shaft  321 . 
     The motor  32  is supplied with external power, and rotates the shaft  321  of the motor  32 . For the motor  32  to easily receive external power, the handle  20  may further include a battery (not shown). The battery may include various kinds of battery such as nickel-cadmium (Ni—Cd), nickel-hydride (Ni-MH), lithium-ion (Li-ion), or lithium polymer battery (not shown). Rotational axis MA advantageously coincides with the central axis of the shaft  321  of the motor  32 . Since the eccentric cam  31  is rotated by the motor  32 , the eccentric cam body  313 , eccentric cam neck  312  and eccentric cam head  311 , all that will be described below, rotate about the rotational axis MA. 
     One side of the eccentric cam body  313  is connected to the shaft  321  of the motor  32 , to co-rotate therewith, as shown in  FIGS.  2  and  6   . The central axis of the eccentric cam body  313  advantageously coincides with rotational axis MA. Therefore, the eccentric cam body  313  and the shaft  321  of the motor  32  can coaxially rotate by sharing rotational axis MA of the motor  32 . The eccentric cam body  313  is preferably cylindrical in shape to facilitate rotation. However, the present disclosure is not limited thereto, and the eccentric cam body  313  may have various shapes such as a polygonal column, a sphere, and the like. 
     The eccentric cam body  313  has its other side connected with one side of the eccentric cam neck  312  so that the eccentric cam neck  312  co-rotates with the eccentric cam body  313 . At this time, the eccentric cam neck  312  is eccentrically connected to the eccentric cam body  313  so that the central axis of the eccentric cam neck  312  does not coincide with rotational axis MA. The eccentric cam neck  312  preferably has a cylindrical or truncated cone shape, but is not limited thereto and may have various shapes. When the eccentric cam neck  312  has a shape of a truncated cone having varying diameter along its height, as shown in  FIG.  6   , the largest diameter of the eccentric cam neck  312  is still smaller than the diameter of the eccentric cam body  313  as well as the diameter of the eccentric cam head  311 . The embodiments, however, are not necessarily limited to this configuration. The diameter of the eccentric cam neck  312  may be larger than that of the eccentric cam body  313  or that of the eccentric cam head  311 . Some embodiments even save the eccentric cam neck  312  by directly interconnecting the eccentric cam body  313  and the eccentric cam head  311 . 
     The eccentric cam neck  312  has its other side connected to one side of the eccentric cam head  311  so that the eccentric cam head  311  corotates with the eccentric cam neck  312 . The eccentric cam head  311  may share the central axis of the eccentric cam neck  312  coaxially, wherein the eccentric cam head  311  has its central axis CA deviating from rotational axis MA. As shown in  FIGS.  2  and  6   , the eccentric cam head  311  according to at least one embodiment of the present disclosure has a substantially spherical shape. This allows the eccentric cam head  311  and the eccentric cam receptacle  113  to be smoothly brought into contact with each other when the cartridge  10  is pivoted about the cartridge connector  40 . Therefore, the entire eccentric cam head  311  favorably has a certain curvature. 
     The eccentric cam head  311  may have the shape of a sphere in a part as well as the entirety of the outer peripheral surface. Therefore, only a part of the eccentric cam head  311  may have a constant curvature. One side of the eccentric cam head  311  is connected to the eccentric cam neck  312 . At this time, the one side of the eccentric cam head  311 , connected to the eccentric cam neck  312 , and the other opposite side of the eccentric cam head  311  may have different respective curvatures from those of the remaining portions of the eccentric cam head  311  except for the one side and the other side. In addition, the one side and the other side of the eccentric cam head  311  may even have a curvature of zero or an aspherical surface. On the other hand, the remaining portions of the eccentric cam head  311  except for the one side and the other side preferably have a constant curvature since they have a spherical shape. The remaining portion of the eccentric cam head  311  except for the one side and the other side may include a contact face CF on which an actual contact with the eccentric cam receptacle  113  may occur. This is to allow the eccentric cam head  311  and the eccentric cam receptacle  113  to be smoothly brought into contact with each other when the cartridge  10  is pivoted about the cartridge connector  40 . 
     However, the shape of the eccentric cam receptacle  113  according to the embodiments of the present disclosure is not limited to a spherical shape, and may have a shape of a polygonal, a cylinder, or the like. Furthermore, the eccentric cam head  311  may not have the shape of a sphere, but may have a shape of an ellipsoid protruding partly, and even further, may not have a constant curvature. That is, the eccentric cam head  311  according to the embodiments of the present disclosure may have various forms without limitation as long as it can contact the eccentric cam receptacle  113  to move the blade housing  11 . 
     In summary, the motor  32 , eccentric cam body  313 , eccentric cam neck  312  and eccentric cam head  311  are sequentially connected to each other, so that the shaft  321  of the motor  32  and the central axis of the eccentric cam body  313  share rotational axis MA coaxially, and central axis CA of both the eccentric cam head  312  and the eccentric cam head  311  are eccentrically connected to rotational axis MA. However, the present disclosure is not limited to this, and the central axis of the eccentric cam neck  312  may be coaxial with rotational axis MA, or the central axis of the eccentric cam body  313  may be eccentrically connected to rotational axis MA. Yet, central axis CA of the eccentric cam head  311  according to some embodiments of the present disclosure remains to be eccentrically connected to the rotational axis MA. Accordingly, central axis CA of the eccentric cam head  311  rotates or revolves about rotational axis MA, which can convert the rotational motion of the eccentric cam head  311  to the linear motion of the blade housing  11 . 
     Central axis CA of the eccentric cam head  311  and rotational axis MA do not coincide and are parallel to each other. Thus, a certain distance (e) exists between central axis CA of the eccentric cam head  311  and rotational axis MA. Distance (e) may dictate the amplitude of the linear motion of the blade housing  11 . A detailed description thereof will be provided below. 
       FIG.  7    is a side view of the blade housing  11  and the eccentric cam  31  as coupled together according to at least one embodiment of the present disclosure. 
     As described above, the blade housing  11  is formed with the eccentric cam receptacle  113  on its rear surface. Then, the upper receiving section  113   a , the lower frame side  112   d  of the blade housing  11 , and the lower receiving section  113   b  have a substantially ‘ ’ symbol shape. As shown in  FIG.  7   , the upper receiving section  113   a  and the lower receiving section  113   b  are spaced apart from each other by a certain distance. The certain distance of a space formed between the upper receiving section  113   a  and the lower receiving section  113   b  accommodates insertion of the eccentric cam head  311  of the eccentric cam  31 , to transmit the drive of the power unit  30  to the cartridge  10 . At this time, the certain distance in the space between the upper receiving section  113   a  and the lower receiving section  113   b  is represented by a length S which corresponds to a diameter D of the eccentric cam head  311  in some embodiments, so that the eccentric cam head  311  can easily enter the space. While the upper receiving section  113   a  and the lower receiving section  113   b  are spaced by length S which corresponds to diameter D of the eccentric cam head  311 , smooth rotation of the eccentric cam head  311  takes some difference between length S and diameter D, which will be detailed below. 
     When the eccentric cam head  311  rotates eccentrically as the motor  32  rotates, the eccentric cam receptacle  113  in contact with the eccentric cam head  311  is subjected to the rotational force of the eccentric cam head  311 . At this time, since the eccentric cam receptacle  113  is formed on the upper and lower sections of the eccentric cam head  311 , the eccentric cam receptacle  113  is controlled by the upward and downward components of the rotational force of the eccentric cam head  311 . However, since the eccentric cam receptacle  113  does not contact the left and right sides of the eccentric cam head  311 , it is not controlled by the leftward and rightward components of the rotational force. Therefore, the eccentric cam receptacle  113  is influenced by the components of the rotational force of the eccentric cam head  311  that are directed upward and downward. This will be described in detail referring to  FIGS.  8  to  10   . 
       FIGS.  8  to  10    are schematic views showing the movement of the eccentric cam receptacle  113  according to the rotational motion of the eccentric cam head  311  according to at least one embodiment of the present disclosure.  FIGS.  11  to  13    are side cross-sectional views taken along line L-L′ in  FIG.  4   , showing the change of the cartridge  10  according to at least one embodiment of the present disclosure, when the blade housing  11  linearly moves with respect to the guide member  12  according to the movement of the eccentric cam receptacle  113  in  FIGS.  8  to  10   . 
     The eccentric cam head  311  is eccentrically connected to the rotational axis MA. Therefore, when the eccentric cam head  311  rotates, central axis CA of the eccentric cam head  311  rotates or revolves around rotational axis MA. As shown in  FIG.  8   , the eccentric cam head  311  during the rotation comes into contact with the lower receiving section  113   b .  FIG.  8    corresponds to  FIG.  11   . Specifically, before the eccentric cam head  311  contacts and pushes the lower receiving section  113   b  downward as shown in  FIG.  8   , that is, in the negative Y-axis direction, the blade housing  11  is located at the uppermost position as shown in  FIG.  11   . At this time, the height of the inner space of the guide member  12  according to at least one embodiment corresponds to twice the amplitude of the blade housing  11  when the blade housing  11  performs sliding reciprocating movement in the Y-axis direction. 
     Contact face CF of the eccentric cam head  311  is defined as the surface on which the eccentric cam head  311  comes in contact with the eccentric cam receptacle  113 . When the eccentric cam receptacle  113  moves downward, that is, in the negative Y-axis direction, contact face CF of the eccentric cam head  311  contacts the lower receiving section  113   b , and when the eccentric cam receptacle  113  moves upward in the Y-axis direction, contact face CF of the eccentric cam head  311  contacts the upper receiving section  113   a . Contact face CF of the eccentric cam head  311  when contacting the lower receiving section  113   b  may coincide with that of the eccentric cam head  311  when contacting the upper receiving section  113   a , which, however, may not always be the case, but is subject to change from time to time. 
     As shown in  FIG.  9   , the eccentric cam head  311  rotates and pushes the lower receiving section  113   b  gradually downward, that is, in the negative Y-axis direction, using the rotational force. As described above, the linear motion of the eccentric cam receptacle  113  is controlled by the upward and downward components of the rotational force of the eccentric cam head  311 . Therefore, the force of pushing the lower receiving section  113   b  downward, that is, the negative Y-axis direction at this time, is a downward component of the rotational force of the eccentric cam head  311 . At this time,  FIG.  9    corresponds to  FIG.  12   . Specifically, when the eccentric cam head  311  pushes the lower receiving section  113   b  gradually downward as shown in  FIG.  9   , that is, in the negative Y-axis direction, the blade housing  11  also moves linearly downward with respect to the guide member  12 , that is, in the negative Y-axis direction, as shown in  FIG.  12   . 
     As shown in  FIG.  10   , when the eccentric cam head  311  is positioned near the lowermost end, the lower receiving section  113   b  is positioned at the lowermost position.  FIG.  10    corresponds to the case of  FIG.  13   . Specifically, when the lower receiving section  113   b  is positioned near the lowermost end as shown in  FIG.  10   , the blade housing  11  is also positioned at the lowermost position with respect to the guide member  12 , as shown in  FIG.  13   . At this time, the lower frame side  112   d  of the blade housing  11  is positioned close to the rubber guard  122  of the guide member  12 , as described above referring to  FIG.  5   . In some embodiments, little to no step is formed between the blade housing  11  and the guide member  12  at the front surface of the cartridge  10 . Any step or difference in leveling may be due to tolerances during the manufacturing process or may be intentionally induced for user&#39;s convenience. 
     After this moment, continued rotation of the eccentric cam head  311  disengages contact face CF of the eccentric cam head  311  from the lower receiving section  113   b , and further rotation thereof brings contact face CF of the eccentric cam head  311  into contact with the upper receiving section  113   a . Then, the process described above referring to  FIGS.  8  to  10    is repeated with respect to the upper receiving section  113   a  instead of the lower receiving section  113   b . Specifically, when the eccentric cam head  311  pushes the upper receiving section  113   a  upward gradually, that is, in the Y-axis direction by using the rotational force, the upper receiving section  113   a  moves upward. At this time, the blade housing  11  also slides relative to the guide member  12  and linearly moves upwardly, that is, in the Y-axis direction, and the cartridge  10  changes in the reverse order from that described referring to  FIGS.  11  to  13   . 
     On the other hand, as shown in  FIGS.  8  to  10   , distance (e) is constant between rotational axis MA and central axis CA of the eccentric cam head  311 . This is because the eccentric cam head  311  is eccentrically connected to rotational axis MA. Distance (e) between rotational axis MA and central axis CA of the eccentric cam head  311  is an eccentricity of the eccentric cam head  311 , and it is associated with the amplitude of the rotational motion of the eccentric cam head  311 . This will be described in detail below. 
     Among the upper, lower, left, right, front, and back directions used for the above description, the description of the orientation of the cartridge  10  is based on the X, Y and Z axes. However, the orientation of the eccentric cam head  311  is independent of the X, Y and Z axes. This is because the X, Y and Z axes refer to the cartridge  10 . Since the cartridge  10  can pivot, it may have up, down, left, right, front and rear directions different from those of the eccentric cam head  311 . In describing directions of the eccentric cam  31 , the reference is based on the direction shown in the drawing, as mentioned above. However, this is for convenience of description of the present disclosure, and does not limit the scope of the present disclosure. 
       FIGS.  14  to  16    are partial side cross-sectional views of a razor, showing changes of a cartridge  10  according to another embodiment of the present disclosure, when a blade housing  11  linearly moves with respect to a guide member  12  according to the movement of the eccentric cam receptacle  113  in  FIGS.  8  to  10   . 
       FIG.  14    of another embodiment corresponds to  FIG.  8   . Specifically, before the eccentric cam head  311  contacts and pushes the lower receiving section  113   b  downward as shown in  FIG.  8   , that is, in the negative Y-axis direction, the housing  11  is located at the uppermost position as shown in  FIG.  14   . At this time, it is preferable that the height of the inner space of the guide member  12  according to another embodiment of the present disclosure corresponds to the height of the blade housing  11 , that is, equal thereto or to be larger than that by an offset amount. However, unlike the at least one embodiment of the present disclosure, the upper part of the guide member  12  is opened. Therefore, the blade housing  11  according to another embodiment of the present disclosure protrudes upwardly with respect to the guide member  12 , that is, in the Y-axis direction, as shown in  FIG.  14   . 
       FIG.  15    of another embodiment corresponds to  FIG.  9   . Specifically, when the eccentric cam head  311  pushes the lower receiving section  113   b  gradually downward as shown in  FIG.  9   , that is, in the negative Y-axis direction, the blade housing  11  slides and linearly moves downward with respect to the guide member  12  as shown in  FIG.  15   , that is, in the negative Y-axis direction. 
       FIG.  16    of another embodiment corresponds to  FIG.  10   . Specifically, when the lower receiving section  113   b  is positioned at the lowermost position as shown in  FIG.  10   , the blade housing  11  is also located at the lowermost position with respect to the guide member  12 , as shown in  FIG.  16   . At this time, the lower frame side  112   d  of the blade housing  11  comes close to the rubber guard  122  of the guide member  12 , as described with reference to  FIG.  5   . 
       FIG.  17    is a rear perspective view of a blade housing  11  according to yet another embodiment of the present disclosure. 
     As described above, the eccentric cam receptacle  113  is formed on the rear surface of the blade housing  11  so as to be able to contact the power unit  30 . However, according to yet another embodiment of the present disclosure, the eccentric cam receptacle  113  includes only the lower receiving section  113  without an upper receiving section. 
     According to at least one embodiment of the present disclosure, the eccentric cam head  311  of the eccentric cam  31  is inserted into the space formed between the upper receiving section  113   a  and the lower receiving section  113   b , as will be described in detail below. Rotation of the eccentric cam head  311  enables the drive of the power unit  30  to be transmitted to the cartridge  10 . 
     Whereas, according to yet another embodiment of the present disclosure, there is no upper receiver, and thus, the eccentric cam head  311  cannot transmit the rotational force to the upper direction when rotating. Therefore, when the blade housing  11  is positioned at the lowermost position with respect to the guide member  12 , even with the eccentric cam head  311  rotating, the blade housing  11  does not slide and linearly move relative to the guide member  12 . 
     At this time, when the user cuts the body/facial hairs, frictional force is generated above the cartridge  10  while the skin-contact face SF of the cartridge  10  comes in contact with the skin. This frictional force enables the blade housing  11  to slide with respect to the guide member  12  and to linearly move upwardly, that is, in the Y-axis direction. After the blade housing  11  linearly moves upward, when the eccentric cam head  311  gradually pushes the lower receiving section  113  downward, that is, in the negative Y-axis direction, the blade housing  11  also slides with respect to the guide member  12 , and linearly moves downward, that is, in the negative Y-axis direction. 
     In other words, yet another embodiment of the present disclosure has the eccentric cam receptacle  113  formed only at the lower portion of the eccentric cam head  311 , so that the eccentric cam receptacle  113  is controlled exclusively by the downward components of the rotational force of the eccentric cam head  311 . However, since the eccentric cam receptacle  113  does not contact the upper, left, and right portions of the eccentric cam head  311 , it is not controlled by the upward, leftward and rightward components of the rotational force. Therefore, the eccentric cam receptacle  113  is influenced only by the downward component of the rotational force of the eccentric cam head  311 . 
       FIG.  18    is a side view of the cartridge  10  being positioned in the initial state according to at least one embodiment, when the eccentric cam head  311  is at the lowermost position.  FIG.  19    is a side view of the cartridge  10  shown in  FIG.  18   , when pivoted.  FIG.  20    is a side view of the cartridge  10  shown in  FIG.  18    without the guide member  12  and the cartridge connector  40 .  FIG.  21    is a side view of the blade housing  11  shown in  FIG.  20   , when pivoted. Here, the initial state refers to a state of the motor  32  before rotation. According to at least one embodiment of the present disclosure, in the initial state, the skin-contact face SF of the cartridge  10  establishes an acute angle with respect to rotational axis MA of the motor  32 . However, the initial state may be varied according to various embodiments of the present disclosure. A detailed description thereof will follow. 
     As described above, the cartridge connector  40  interconnects the guide member  12  and the handle  20  and provides a pivot axis PA for the cartridge  10  to pivot. Referring back to  FIG.  2   , the cartridge connector  40  is formed on both sides with bosses  41  protruding outwardly. The guide member  12  is formed on both sides with boss grooves  123 , respectively. The cartridge connector  40  and the guide member  12  may be coupled by inserting the bosses  41  formed in the cartridge connector  40  into the boss grooves  123  formed in the guide member  12 . As shown in  FIGS.  18  and  19   , the cartridge  10  pivots about the bosses  41  of the cartridge connector  40 . Thus, pivot axis PA, which is the center of the pivoting of the cartridge  10 , is established interconnecting the bosses  41  formed on both sides of the cartridge connector  40  as shown in  FIG.  2   . 
     The arrangement of  FIG.  20    corresponds to that of  FIG.  18   , and the arrangement of  FIG.  21    corresponds to that of  FIG.  19   . In other words, pivot axis PA, when the eccentric cam head  311  is positioned at the lowermost position as shown in  FIG.  18   , occupies its highest relative position with respect to the center CC of the eccentric cam head  311 . Therefore, when the eccentric cam head  311  is moved upward gradually while rotating, pivot axis PA moves downward relatively with respect to the central axis CA of the eccentric cam head  311 . 
     It is preferable that the pivot axis PA is positioned to pass through the eccentric cam head  311 . It is more preferable that the pivot axis PA passes through center CC of the eccentric cam head  311 , but the embodiment is not limited thereto. This is because the eccentric cam head  311  being captured within the eccentric cam receptacle  113  is susceptible to fall out of the eccentric cam receptacle  113  when the cartridge  10  pivots, provided that pivot axis PA is positioned off the line extending through the eccentric cam head  311 , possibly resulting in failed delivery of the drive for linearly moving the blade housing  11 . Even if the arrangement of pivot axis PA being positioned off the line extending through the eccentric cam head  311  does not necessarily result in complete disengagement of the eccentric cam head  311  from the eccentric cam receptacle  113  when the cartridge  10  pivots, such eccentric arrangement as triggered by the pivoting cartridge  10  causes unnecessary interference to be increased between the eccentric cam head  311  and the eccentric cam receptacle  113 , to restrict the range of up and down movements of the blade housing  11  or increase noise, leading to decreased comfort when the razor is used. 
     The pivot axis PA may pass through center CC of the eccentric cam head  311 , but the embodiment is not limited thereto, and it may be located close to the eccentric cam head  311 . When the pivoting of the cartridge  10  occurs with pivot axis PA lying at center CC of the eccentric cam head  311 , constant distance can be maintained between the contact portions of the eccentric cam receptacle  113  and eccentric cam head  311 . Therefore, elimination of unnecessary interference between the eccentric cam head  311  and the eccentric cam receptacle  113  permits the blade housing  11  provided with the eccentric cam receptacle  113  to be smoothly pivoted up and down without jolting. Therefore, coinciding pivot axis PA with center CC of the eccentric cam head  311  is superior to the eccentric arrangement therebetween in providing a sense of security with an increased closeness. 
     Although not shown in the drawings, when the eccentric cam head  311  is located at the uppermost position, the pivot axis PA is located at the lowest position relative to central axis CA of the eccentric cam head  311 . Therefore, as the eccentric cam head  311  gradually moves downward while rotating, the pivot axis PA relatively moves upwards with respect to central axis CA of the eccentric cam head  311 . 
     Meanwhile, the bosses  41  of the cartridge connector  40  have a round cylinder shape as shown in  FIG.  2   . This is to facilitate a smooth contact between the bosses  41  and the boss grooves  123 , when the cartridge  10  pivots about the bosses  41 . However, the present disclosure is not limited to this, and the bosses  41  may have a partial surface curved into a columnar shape. The sizes of the bosses  41  and the bosses  123  correspond to each other. More specifically, the size of the bosses  123  is larger than the size of the bosses  41 . Preferably, the cartridge  10  is restrained with respect to the cartridge connector  40  against movement other than pivoting. On the other hand, one side of the cartridge connector  40  is fixedly coupled with the handle  20 , resulting in the cartridge  10  pivoting with respect to the handle  20 . 
       FIG.  22    is a side view of the cartridge  10  being subjected to a torque T 2  generated by the drive of the motor  32 , when an angle θ is an acute angle between skin-contact face SF of the cartridge  10  and rotational axis MA of the motor  32 . 
     As described above, the initial state means that the motor  32  does not rotate. When angle θ between skin-contact face SF of the cartridge  10  and rotational axis MA of the motor  32  is an acute angle and the motor  32  starts to rotate, a force acts on the upper receiving section  113   a , as shown in  FIG.  22   . Specifically, the eccentric cam head  311 , when moving upward, generates F 1  which is an upward component of the rotational force of the eccentric cam head  311 . F 1  may be divided into F 2  which is the component in the Y-axis direction of the cartridge  10 , and F 3  which is the component in the negative Z-axis direction of the cartridge  10 . Since F 2  and F 3  are the component forces of F 1 , they can be expressed as follows. 
         F   2   =F   1  sin θ
 
         F   3   =F   1  cos θ  Equation 1
 
     Here, θ is the angle formed by the skin-contact face SF of the cartridge  10  and the rotational axis MA of the motor  32 , as shown in  FIG.  22   . As described above, when the eccentric cam head  311  moves upward while rotating, the upper receiving section  113   a  is pushed up in the Y-axis direction, and the blade housing  11  linearly moves. The force that pushes up the upper receiving section  113   a  in the Y-axis direction is the component force of F 2  in the Y-axis direction of F 1 . By the way, by component force F 3  in the negative Z-axis direction of F 1 , the upper receiving section  113   a  is also forced in the negative Z-axis direction. The action of F 2  and F 3  generates torque T 2  to allow the cartridge  10  to be automatically pivoted. Specifically, the equation of torque T 2  acting on the cartridge  10  is as follows. 
     
       
         
           
             
               
                 
                   
                     
                       
                         
                           T 
                           2 
                         
                         = 
                           
                         
                           ∑ 
                           
                             r 
                             × 
                             F 
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                           
                         
                           
                             ( 
                             
                               
                                 r 
                                 3 
                               
                               × 
                               
                                 F 
                                 3 
                               
                             
                             ) 
                           
                           + 
                           
                             ( 
                             
                               
                                 r 
                                 2 
                               
                               × 
                               
                                 F 
                                 2 
                               
                             
                             ) 
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                           
                         
                           
                             ( 
                             
                               
                                 r 
                                 3 
                               
                               × 
                               
                                 F 
                                 1 
                               
                               ⁢ 
                               cos 
                               ⁢ 
                               θ 
                             
                             ) 
                           
                           + 
                           
                             ( 
                             
                               
                                 r 
                                 2 
                               
                               × 
                               
                                 F 
                                 1 
                               
                               ⁢ 
                               sin 
                               ⁢ 
                               θ 
                             
                             ) 
                           
                         
                       
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                       
                   2 
                 
               
             
           
         
       
     
     Here, the positive (+) direction of the torque is set as the clockwise direction. The components corresponding to r and F are all vectors, and x denotes a vector product. In addition, r 2  is the vertical distance from pivot axis PA to F 2 , and r 3  is the vertical distance from pivot axis PA to F 3 . As described above, each time the eccentric cam head  311  rotates, the relative position of pivot axis PA changes, so that r 2  and r 3  can also change. However, since r 2  is a relatively miniscule value, its changes are ignorable. 
         r   2   ≈O   Equation 3
 
     Therefore, torque T 2  is calculated as follows. 
         T   2   ≈r   3   ×F   1 ×cos θ  Equation 4
 
     As can be seen from Equation 4, the smaller the angle θ between the skin-contact face SF and the rotational axis MA in the initial state, the larger the torque T 2 . However, if the torque T 2  is excessively large, the user&#39;s shaving comfort is reduced, and the user may feel uncomfortable. Therefore, it is not preferable to set angle θ between skin-contact face SF and rotational axis MA to be excessively small in the initial state. Empirically, in order to enhance the user&#39;s shaving comfort, angle θ is preferably formed to be 30 to 60 degrees in the initial state by skin-contact face SF and rotational axis MA according to an embodiment of the present disclosure. Empirically, angle θ larger than 60 degrees reduces the user&#39;s shaving comfort or renders the user to feel uncomfortable. Angle θ smaller than 30 degrees considerably reduces the linear motion amplitude of the blade housing  11 , making it hard to obtain the effect of the present disclosure, and the lower receiving section  113   b  may be interfered by the eccentric cam neck  312 . More preferably, angle θ formed by skin-contact face SF and rotational axis MA may be 40 to 50 degrees. 
       FIG.  23    is a side view of the cartridge  10  being subjected to torque T 2  generated by the drive of motor  32 , when angle θ is an obtuse angle between skin-contact face SF of the cartridge  10  and rotational axis MA of the motor  32 . 
     When angle θ between skin-contact face SF of the cartridge  10  and rotational axis MA of the motor  32  is an obtuse angle and the motor  32  starts to rotate, the eccentric cam head  311  moving upward generates F 1  which is an upward component of the rotational force of the eccentric cam head  311 , as shown in  FIG.  23   . F 1  may be divided into F 2  which is the component in the Y-axis direction of the cartridge  10  and F 3  which is the component in the Z-axis direction of the cartridge  10 . Since F 2  and F 3  are the component forces of F 1 , they can be expressed as follows. 
         F   2   =F   1  sin(π−θ)= F   2  sin θ
 
         F   3   =F   1  cos(π−θ)= F   2  cos θ  Equation 5
 
     At this time, the equation of torque T 2  is as follows. 
     
       
         
           
             
               
                 
                   
                     
                       
                         
                           T 
                           2 
                         
                         = 
                           
                         
                           ∑ 
                           
                             r 
                             × 
                             F 
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                           
                         
                           
                             ( 
                             
                               
                                 r 
                                 3 
                               
                               × 
                               
                                 F 
                                 3 
                               
                             
                             ) 
                           
                           + 
                           
                             ( 
                             
                               
                                 r 
                                 2 
                               
                               × 
                               
                                 F 
                                 2 
                               
                             
                             ) 
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                           
                         
                           
                             ( 
                             
                               
                                 r 
                                 3 
                               
                               × 
                               
                                 F 
                                 1 
                               
                               ⁢ 
                               
                                 cos 
                                 ( 
                                 
                                   π 
                                   - 
                                 
                                   
                                 ) 
                               
                               ⁢ 
                               θ 
                             
                             ) 
                           
                           + 
                           
                             ( 
                             
                               
                                 r 
                                 2 
                               
                               × 
                               
                                 F 
                                 1 
                               
                               ⁢ 
                               
                                 sin 
                                 ⁡ 
                                 ( 
                                 
                                   π 
                                   - 
                                     
                                   θ 
                                 
                                 ) 
                               
                             
                             ) 
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                           
                         
                           
                             ( 
                             
                               
                                 r 
                                 3 
                               
                               × 
                               
                                 - 
                                 
                                   F 
                                   1 
                                 
                               
                               ⁢ 
                               cos 
                               ⁢ 
                               θ 
                             
                             ) 
                           
                           + 
                           
                             ( 
                             
                               
                                 r 
                                 2 
                               
                               × 
                               
                                 F 
                                 1 
                               
                               ⁢ 
                               sin 
                               ⁢ 
                               θ 
                             
                             ) 
                           
                         
                       
                     
                   
                   
                     
                       
                         
                           
                             = 
                             
                               . 
                             
                           
                           
                             . 
                           
                         
                           
                         
                           
                             r 
                             3 
                           
                           × 
                           
                             F 
                             1 
                           
                           × 
                           cos 
                           ⁢ 
                           θ 
                         
                       
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                       
                   6 
                 
               
             
           
         
       
     
     Here, too, the positive (+) direction of the torque is set as the clockwise direction. However, cos θ is a negative number because angle θ between skin-contact face SF and rotational axis MA is an obtuse angle. Therefore, torque T 2  is also negative and acts counterclockwise. In addition, r 2  is a relatively miniscule value and can be ignored. 
     As can be seen from Equation 6, the smaller the angle θ between the skin-contact face SF and the rotational axis MA in the initial state, the larger the torque T 2 . However, if the torque T 2  is excessively large, the user&#39;s shaving comfort is reduced, and the user may feel uncomfortable. Therefore, it is not preferable to set angle θ between skin-contact face SF and rotational axis MA to be excessively small in the initial state. 
       FIG.  24    is a side view of the cartridge  10  not being subjected to torque T 2  generated by the drive of the motor  32 , when angle θ is a right angle between skin-contact face SF of the cartridge  10  and rotational axis MA of the motor  32 . 
     When angle θ between skin-contact face SF of the cartridge  10  and rotational axis MA of the motor  32  is a right angle and the motor  32  starts to rotate, the eccentric cam head  311  moving upward generates F 1  which is an upward component of the rotational force of the eccentric cam head  311 , as shown in  FIG.  24   . In this case, the upper side of the eccentric cam head  311  and the upper side of the cartridge  10 , that is, they are commonly directed toward the Y-axis direction. Therefore, since F 1  acts only in the Y-axis direction, F 2  and F 1 , which are the forces in the Y-axis direction, are the same. On the other hand, since F 1  does not act in the Z-axis direction at all, F 3 , which is the force in the Z-axis direction, becomes zero. 
         F   2   =F   1  sin θ= F   1  sin 90°= F   1  
 
         F   3   =F   1  cos θ= F   1  cos 90°=0  Equation 7
 
     At this time, the equation of torque T 2  is as follows. 
     
       
         
           
             
               
                 
                   
                     
                       
                         
                           T 
                           2 
                         
                         = 
                           
                         
                           ∑ 
                           
                             r 
                             × 
                             F 
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                           
                         
                           
                             ( 
                             
                               
                                 r 
                                 3 
                               
                               × 
                               
                                 F 
                                 3 
                               
                             
                             ) 
                           
                           + 
                           
                             ( 
                             
                               
                                 r 
                                 2 
                               
                               × 
                               
                                 F 
                                 2 
                               
                             
                             ) 
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                           
                         
                           ( 
                           
                             
                               r 
                               2 
                             
                             × 
                             
                               F 
                               1 
                             
                             ⁢ 
                             sin 
                             ⁢ 
                             θ 
                           
                           ) 
                         
                       
                     
                   
                   
                     
                       
                         
                           
                             = 
                             
                               . 
                             
                           
                           
                             . 
                           
                         
                           
                         0 
                       
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                       
                   8 
                 
               
             
           
         
       
     
     Since r 2  is a relatively miniscule value, it can be ignored. As Equation 8 tells, torque T 2  does not occur when the angle θ formed by skin-contact face SF of the cartridge  10  and rotational axis MA of the motor  32  is a right angle. 
     As explained through various embodiments of the present disclosure, the magnitude of torque T 2  varies according to angle θ formed by the skin-contact face SF and the rotational axis MA. However, in the embodiments, the cartridge  10  is automatically pivoted by the motor  32  when rotating so that angle θ between the skin-contact face SF and the rotational axis MA becomes a right angle. However, when angle θ formed by the skin-contact face SF and the rotational axis MA is a right angle from the initial state, it is no longer necessary for the cartridge  10  to pivot automatically, so that torque T 2  will not be generated. 
     The initial state of the cartridge  10  according to various embodiments of the present disclosure is most preferable when the angle θ between the skin-contact face SF and the rotational axis MA is an acute angle. This offers the best comfort in use and the natural angle when the user grasps the razor  1  by hand and cuts the body/facial hairs. However, as described above, if the torque T 2  is excessively large, the user&#39;s shaving comfort is reduced. Therefore, when the initial state of the cartridge  10  is set as the state where the angle θ formed by the skin-contact face SF and the rotational axis MA is an acute angle, the cartridge connector  40  is provided with a restoration unit for which at least one cantilever  125  is used by this embodiment, as will be explained below. The above description does not limit the scope of the present disclosure, and the razor  1  of the present disclosure can include various embodiments. 
       FIG.  25    is an enlarged, partial view of a region R shown in  FIG.  22   . 
     As described above, the eccentric cam head  311  is inserted into the space between the upper receiving section  113   a  and the lower receiving section  113   b  of the eccentric cam receptacle  113  so that the power of the power receiving portion  113  is transmitted to the cartridge  10 . Distance (e) is constant between rotational axis MA and the central axis CA of the eccentric cam head  311 . This is because the eccentric cam head  311  is eccentrically connected to the rotational axis MA. Distance (e) between the rotational axis MA and the central axis CA of the eccentric cam head  311  is an eccentricity (e) of the eccentric cam head  311 . 
     The upper receiving section  113   a  and the lower receiving section  113   b  are formed side by side with a predetermined distance or interval therebetween and are parallel to the upper frame side  112   c  and the lower frame side  112   d . The predetermined distance in the space between the upper receiving section  113   a  and the lower receiving section  113   b  is represented by length S which corresponds to the diameter D of the eccentric cam head  311 , so that the eccentric cam head  311  can easily enter the space. 
     While the upper receiving section  113   a  and the lower receiving section  113   b  are spaced by the length S which corresponds to the diameter D of the eccentric cam head  311 , there exists some difference between length S and diameter D such that the eccentric cam head  311  rotates smoothly, as shown in  FIG.  25   . 
     
       
         
           
             
               
                 
                   t 
                   = 
                   
                     
                       S 
                       - 
                       D 
                     
                     2 
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                       
                   9 
                 
               
             
           
         
       
       
         
           
             Amplitude 
             = 
             
               
                 ( 
                 
                   e 
                   × 
                   sin 
                   ⁢ 
                   θ 
                 
                 ) 
               
               - 
               t 
             
           
         
       
     
     Here, S denotes a length of a predetermined interval formed in the eccentric cam receptacle  113 , D denotes a diameter of the eccentric cam head  311 , and t denotes the difference in length between the eccentric cam receptacle  113  and the eccentric cam head  311 , as calculated by the average of the differences between the upper receiving section  113   a  and the lower receiving section  113   b . The amplitude is that of the blade housing  11  when reciprocating. 
     As indicated in Equation 9, the amplitude of the reciprocating motion depends on angle θ between the skin-contact face SF and the rotational axis MA, the eccentricity (e) of the eccentric cam head  311 , and the aforementioned difference in length. If the amplitude is too small, the efficiency of hair cutting is not remarkably enhanced, and if the amplitude is too large, the user&#39;s shaving comfort is reduced. Therefore, by empirically adjusting the above conditions, the most appropriate amplitude can be set. 
       FIG.  26    is a cross-sectional side view of the cartridge  10  according to at least one embodiment of the present disclosure, taken along line K-K′ in  FIG.  4   , and  FIG.  27    is a cross-sectional side view of the cartridge connector  40  coupled to the cartridge  10  shown in  FIG.  26   . 
     As shown in  FIG.  27   , the cartridge connector  40  includes at least one cantilever  125 . The cantilever  125  serves to restore the cartridge  10  to its initial condition in case the cartridge  10  is excessively pivoted by the user in shaving or when torque T 2  is excessively generated in the initial state. The cantilever  125  is attached to the front of the cartridge connector  40 , and it protrudes forward, that is, toward the Z-axis direction. 
     The cantilever  125  may be formed from the inside of the cartridge connector  40  toward the cartridge  10 , that is, toward the Z-axis direction, as shown in  FIG.  27   . Alternatively, the cantilever  125  may extend from the lower end of the upper frame side  112   c  that supports the upper section of the guide member  12 . In other words, as long as the cantilever  125  can restore the cartridge  10  when rotating to its initial state, it may be formed at various positions without limitation. 
     The cantilever  125  may be formed as shown in  FIG.  27   , to extend upward from below the cartridge connector  40 , i.e., in the y-axis direction, and then bend so as to be in terminally contact with the cartridge  10 . Alternatively, the cantilever  125  may have the shape of a curved surface having a predetermined curvature, wherein the curved surface may be configured to have only a positive slope or inclination with respect to the Z axis, or may have a slope of zero or more. In addition, the cantilever  125  may have a curved surface having a shape in which the inclination decreases toward the rear of the guide member  12 , that is, in the negative Z-axis direction. Various other shapes are envisioned without limitation to what is illustrated herein. 
     In addition, two cantilevers  125  may be formed, one on the left side and the other on the right side of the cartridge connector  40 , but the configuration is not limited thereto, and one or more than three cantilevers  125  may be formed. 
     As shown in  FIG.  27   , the cantilever  125  is protruded to contact and support the guide member  12 . When the cartridge  10  pivots, the cantilever  125 &#39;s contact area with the guide member  12  increases, the cantilever  125  is subjected to a force in the z-axis direction, and eventually the cantilever  125  having elasticity pushes the guide member  12  outward. This can support the cartridge  10  so as not to pivot beyond a certain angle, thereby further enhancing the comfort of the user using the razor. At this time, the cantilever  125  is desirably made of a material having elasticity to absorb the impact force. Therefore, even after the cantilever  125  is brought into contact with the barrier (not shown), some deformation occurs, so that some of the impact force can be absorbed. With its elasticity, the cantilever  125  can be restored to its original shape. 
       FIG.  28    is a schematic view of a hair cutting process using a conventional razor, and  FIG.  29    is a schematic view of a hair cutting process using the razor  1 , according to some embodiments of the present disclosure.  FIG.  30    is an SEM photograph of a section of the body/facial hairs cut using a conventional razor.  FIG.  31    is an SEM photograph of a section of the body/facial hair cut using the razor  1  according to some embodiments of the present disclosure. 
     The ideal cutting direction of the hair is generally perpendicular to the direction of hair formation. This is because the area of the cross section is small and the appearance is most clean. 
     As shown in  FIG.  28   , when using a conventional razor, which has a cartridge, like  10  in the drawings, provided with blades like  111  in a frame like  112 , to perform the body/facial hairs cutting once, the frame first contacts the body/facial hairs before the blades do. Then, the frame forcibly bend the body/facial hair toward the skin surface. Subsequent cutting of the hairs by the blades leaves the hairs cut in a direction with a little angular difference between the direction in which the hair is formed. In addition, the hair is not sharply cut by the blades but is forcibly pulled by the user. Such a result is shown in  FIG.  30   , where a so-called tugging phenomenon occurs, i.e., the area of the cross section of the hair is widened and the end of the cross section is elongated and messy. 
     With the razor  1  according to at least one embodiment of the present disclosure, however, the user can perform the body/facial hair cutting in contact with the skin at a manual speed of the body/facial hair cutting by the user, which is accelerated by the automatic linear motion of the blade housing  11 , as shown in  FIG.  29   , accelerating the body/facial hair cutting process, thereby increasing the hair cutting efficiency. 
     In addition, after being cut and curved toward the skin by passing of the blades  111  in direction B, the body/facial hairs get straightened back in the process of returning the blades  111  in direction C, allowing the body/facial hairs to be re-cut while the blades  111  pass again in direction B. This means that multiple haircutting cycles are offered for each shaving action. 
     Specifically, when the blades  111  move in direction B, the speed of moving the razor  1  by hand is combined with the speed of moving the blades  111  by the rotational force of the motor  32 , which accelerates the body/facial hair cutting. Thus, the body/facial hairs are subjected to more force when they are cut, resulting in a cleaner cross-section of the body/facial hairs cut, as shown in  FIG.  31   . 
     With the razor of the present disclosure, the improved hair cutting ability combined with the pivoting of the cartridge  10  further enhances the user&#39;s shaving comfort. Generally, the angle at which the body/facial hairs is cut the best along the skin surface varies. Unless the pivoting is combined, the user would need to adjust the cartridge  10  to closely follow the skin surface to perform the body/facial hair cutting. With the pivoting cartridge  10 , the razor  1  according to at least one embodiment of the present disclosure changes the angle of the body/facial hair cutting along the skin surface without an input from the user. Therefore, the user&#39;s shaving comfort is enhanced, and the body/facial hair cutting can be performed more quickly and accurately. 
     It will be understood by those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the technical idea or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present disclosure is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present disclosure.