Patent Publication Number: US-6669704-B2

Title: Hand-held epilating device

Description:
BACKGROUND ART 
     1. Field of the Invention 
     The present invention is directed to a hand-held epilating device, and more particularly to such a device having a rotary cylinder carrying a plurality of hair pinching rows arranged around an axis of the rotary cylinder. 
     2. Description of the Prior Art 
     U.S. Pat. No. 5,190,559 discloses a prior art epilating device which has a rotary cylinder carrying a pair of hair pinching rows spaced circumferentially around the rotary cylinder. Each of the pinching rows includes a plurality of stationary blades and a plurality of movable blades which are arranged along the lengthwise direction of the rotary cylinder with the tow adjacent movable blades disposed on opposites of each stationary blade. The movable blades in each pinching row are supported to a pair of actuator bars which are driven to counter-reciprocate along the longitudinal axis of the rotary cylinder in order to shift the movable blades towards the adjacent stationary blades for pinching the body hairs between the blades. Subsequently, the pinched hairs are plucked from a user&#39;s skin as the rotary cylinder rotates. In order to catch the hairs between the blades as well as to release the plucked hairs, the actuator bars in each pinching row is urged by a return spring to move the movable blades away from the adjacent stationary bars prior to and subsequent to pinching the hairs. The spring is required between the counter-reciprocating actuator bars in each pinching row. That is, each pinching row necessitates one return spring. Consequently, as the number of the pinching rows increases, a correspondingly increased number of the springs have to be incorporated in the rotary cylinder, which incurs difficulty of assembling the increased number of the springs into the rotary cylinder. Therefore, it has not been practical to provide a large number of the pinching rows yet using the return springs for each of the pinching rows. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished in view of the above insufficiency to provide an improved epilating device which is capable of realizing an increased number of the pinching rows around a rotary cylinder with a minimum number of return springs. The epilating device in accordance with the present invention includes a housing to be grasped by a hand of a user, and a rotary cylinder mounted to the housing and having a longitudinal axis. The rotary cylinder carries a plurality of pinching row units which are circumferentially spaced about the longitudinal axis. Each pinching row units includes at least one set of blades arranged along the longitudinal axis of the cylinder. Also included in the rotary cylinder are a plurality of actuator bars which are arranged circumferentially about the longitudinal axis and are associated with the pinching rows, respectively. Each of the actuator bars extends through the rotary cylinder and is driven to shift along the longitudinal axis. Each actuator is connected to move at least one of the blades in each pinching row unit against and away from the adjacent stationary blade for catching and pinching the body hairs therebetween. A drive mechanism is provided for driving the actuator bars to reciprocate along longitudinal axis while rotating the rotary cylinder about the longitudinal axis for pinching the body hairs between the adjacent blades and plucking the hairs from the user&#39;s skin. The distinguishing feature of the present invention resides in that all the circumferentially spaced actuator bars are coupled commonly to a single return spring so as to be urged thereby in a direction of moving the blades away from the adjacent blade. Accordingly, an increased number of the pinching rows can be realized around the rotary cylinder only with the use of a minimum number of the return spring. 
     It is therefore a primary object of the present invention to provide the epilating device which is capable of achieving efficient hair plucking due to the increased number of the pinching row units around the rotary cylinder, yet ensuring to moving the movable blades away from the adjacent stationary blades by the use of the return spring for successfully catching the hairs with increased hair trapping efficiency. 
     In a preferred embodiment, the return spring includes a plurality of spring arms extending radially from a center hub secured to the rotary cylinder. Each spring arm is held in pressing engagement simultaneously with the circumferentially adjacent actuator bars for urging the bars axially outwardly of the rotary cylinder. Thus, the number of the spring arms can be half that of the circumferentially arranged pinching units, thereby simplifying the structure of the return spring. 
     The spring arm is U-shaped to have a first radial segment extending from the hub and a second radial segment which extends from the outer radial end of said first radial segment through an arc segment and projects radially inwardly from the arc segment. The second radial segment is utilized to be held in pressing engagement commonly with the two circumferentially adjacent actuator bars. With this U-shaped configuration, the second radial segment can be given an effective spring length which is sufficiently long relative to a radial dimension of the return spring, thereby giving a sufficient biasing force for moving the blade away from the adjacent blade only at a minimum radial dimension of the return spring. 
     In order to further increase the spring force, the spring arms are shaped to extend in a spiral fashion from the center hub about an axis of the hub. The hub may be formed with a hole which receives a portion of the rotary cylinder for fixedly mounting the return spring to the rotary shaft as well as for allowing an axle to pass therethrough for supporting the rotary cylinder to the housing. 
     Each of the actuator bars has a first end coupled to at least one blade in each set of blades and has a second end projecting on one longitudinal end face of the rotary cylinder in an opposing relation to a cam roller which is included in the drive mechanism. The cam roller is positioned to be in selective contact with the second ends of the actuator bars in such a manner as to move the actuator bars in a direction of pinching the body hairs between the blades as the rotary cylinder rotates about the longitudinal axis. The second end of each actuator bar is shaped to extend circumferentially about the longitudinal axis give an arcuate flange. The arcuate flanges of the circumferentially adjacent actuator bars are partially overlapped with each other in a radial direction of the rotary cylinder such that the overlapped portions of the arcuate flanges come simultaneously into contact with the cam roller. In this connection, each spring arm of the return spring is engaged with the radially overlapped portions of the arcuate flanges of the two circumferentially adjacent actuator bars. With this arrangement, the arcuate flanges of the adjacent actuator bars come into simultaneous contact with the cam roller to keep pinching the hairs over a prolonged period during which the cylinder continues rotating to pluck the hair successfully. Therefore, it is possible to arrange an increased number of the pinching rows around the rotary cylinder of a limited diameter, yet assuring to make the hair plucking successfully. 
     It is preferred that each of said arcuate flanges is formed at its opposite ends with receding slant faces away from the cam roller in order to reduce an impact when the actuator bars come into contact with the cam roller, thereby assuring smooth closing and opening movement of the blades and therefore reduced-in-noise operation. 
     In a preferred embodiment, each pinching row units includes a plurality of stationary blades and a corresponding number of movable blades which are arranged alternately in a direction parallel to said longitudinal axis. An advantageous feature associated with this embodiment resides in that the two longitudinally adjacent stationary blades in each of said pinching row units are integrally shaped from the same metal into a single integrated piece in which the two adjacent stationary blades are inseparably continuous with each other, and that the integrated piece is associated with the two adjacent movable blades which are connected commonly to one of the actuator bars and are caused thereby to move simultaneously against and away from the stationary blades of the integrated piece. With the use of the integrated piece, the two metal-made stationary blades can be positioned accurately or have precise dimensional relationship with each other, thereby been given uniform pinching effects with the associated movable blades driven to move simultaneously by a single actuator bar. Thus, it is easy to eliminate undesired variation in the hair pinching effects between the stationary blades and therefore to assure consistent and effective hair plucking. 
     Preferably, the two movable blades associated with the integrated piece are pivotally supported to a holder plate so as to be pivotable about a pivot axis perpendicular to the longitudinal axis of the rotary cylinder for movement against and away from the associated stationary blades. The holder plate mounts at least one integrated piece and the associated movable blades and consolidating these members together into a self-sustained sub-assembly which is fitted on the surface of said rotary cylinder. Thus, the pinching row units can be easily assembled to the rotary cylinder for increasing manufacturing efficiency. 
     The holder plates also mounts a skin guide which is disposed between the two adjacent stationary blades of the integrated piece and has an arcuate surface for smooth contact with the skin of the user&#39;s body. The skin guide is consolidated into the sub-assembly and has a grip which fixes the integrated piece to the holder plate in a correct position relative to the corresponding movable blades. The skin guide can be molded from a plastic material so as to be easy to be press-fitted to the holder plate, and is therefore best utilized to unite the metal-made integrated piece, i.e., the stationary blades to the holder. 
     The two adjacent stationary blades are interconnected by a pair of beams extending in the direction of the longitudinal axis and merging at opposite lengthwise ends into lower ends of the stationary blades. Formed at the connection between the beams and the stationary blades are resilient segments which are responsible for absorbing a stress applied to the stationary blade from the associated movable blade. Thus, excessive force applied to one of the stationary blade from the movable blade can be well absorbed at the resilient segments, which making it easy to balance the pinching forces at the two stationary blades for uniform plucking of the hairs. 
     The arcuate surface of the skin guide is formed at its one end with a rounded edge which is continuous with a remainder of the arcuate surface and has a curvature greater than that of the remainder of the arcuate surface. The rounded edge of increased curvature can well prevent the skin from being irritated when the skin guide comes firstly into contact with the skin as a consequence of the rotary cylinder rotates, thereby assuring comfortable hair plucking. 
     Each of the stationary blade and the corresponding movable blade may be formed at its one lengthwise facing toward a rotating direction of said rotary cylinder with a flared edge. The flared edges are cooperative with each other to define therebetween a tapered groove for smoothly guiding the hairs into between the blades. 
     In the preferred embodiment, the two integrated pieces are mounted to the one holder plate to constitute the sub-assembly in which the four stationary blades are evenly spaced along the longitudinal axis of the rotary cylinder. The rotary cylinder carries a plurality of the sub-assemblies which are circumferentially spaced about the longitudinal axis with the sub-assemblies being staggered with each other with respect to the longitudinal axis, in order to increase chances of the hair plucking within the length of the rotary cylinder. For maximum efficiency of plucking the hairs per length of the rotary cylinder, all the stationary blades of different rows are offset from each other with respect to the longitudinal axis of the cylinder. 
     These and still other objects and advantageous features of the present invention will become more apparent from the following description of the preferred embodiment when taken in conjunction with the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of a hand-held epilating device in accordance with a preferred embodiment of the present invention; 
     FIG. 2 is a vertical section of a major portion of the epilating device; 
     FIG. 3 is an exploded perspective view of an epilator head of the epilating device; 
     FIG. 4 is a vertical section of a rotary cylinder constituting the epilator head; 
     FIG. 5 is a perspective view of the rotary cylinder; 
     FIG. 6 is an exploded perspective view of a pinching row unit carried on the rotary cylinder; 
     FIG. 7 is an exploded perspective view of the rotary cylinder; 
     FIG. 8 is a front view of a return spring incorporated in the rotary cylinder; 
     FIG. 9 is a perspective view of the return spring 
     FIG. 10 is a perspective view of the return spring within the rotary cylinder shown with some parts removed for indicating the operative position of the return spring; 
     FIG. 11 is a sectional view of the rotary cylinder; 
     FIG. 12 is an expanded view of the rotary cylinder showing the arrangement of the pinching row units; 
     FIG. 13 is sectional view of a rotary cylinder for a hand-held epilating device in accordance with another embodiment of the present invention; 
     FIG. 14 is a perspective view of a portion of the rotary cylinder showing a return spring and associated parts; 
     FIG. 15 is an exploded perspective view of a pinching row unit mounted on the rotary cylinder; and 
     FIG. 16 is an expanded view of the rotary cylinder showing the arrangement of the pinching row units. 
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Referring now to FIG. 1, there is shown a hand-held epilating device in accordance with a preferred embodiment of the present invention. The epilating device has a housing  10  to be grasped by a user&#39;s hand and an epilator head  30  detachably mounted on top of the housing  10 . The epilator head  30  carries a rotary cylinder  40  which is driven to rotate about its longitudinal axis for plucking body hairs from the skin of a user. The housing  10  accommodates an electric motor and a set of driving gears for providing a driving source of rotating the rotary cylinder  40  and simultaneously vibrating the cylinder along the longitudinal axis for maximizing for maximizing the chance of plucking the hairs on the surface of the rotary cylinder  40 . 
     As shown in FIGS. 2 and 3, the epilator head  30  is composed of a base  31  detachably mounted to the housing  10 , a base cover  32 , a reciprocating platform  33 , a head frame  35  supporting a rotary cylinder  40 , and a head cover  38 . The base  31  carries a first driven gear  21  which comes into meshing engagement with a driving gear (not shown) exposed on top of the housing  10  when the head  30  is attached to the housing. The head frame  35  has an axle  36  which extends between a main-frame  35 - 1  and a sub-frame  35 - 2  which are assembled together with a second driven gear  22  interposed therebetween. The second driven gear  22  meshes with the first driven gear and with a gear  41  formed at one longitudinal end of the rotary cylinder  40  to rotate the cylinder about its longitudinal axis defined by the axle  36 . The head frame  35  is supported to the reciprocating platform  33  which is driven to reciprocate along the axle relative to the base  31  while the rotary cylinder  40  is rotated. For reciprocating the cylinder  40 , the base  31  carries a gear  23  which meshes with one side of the first driven gear  21  to be driven thereby to rotate about an upright axis and has an eccentric cam  24 . The cam  24  engages into a rectangular slot  34  in the bottom of the platform  33  for translating the rotary movement of the gear  23  into the reciprocating movement of the platform  33 . The head cover  37  is secured to the platform  33  and has an opening  38  through which substantially the full length of the rotary cylinder  40  is exposed for contact with the skin of the user. 
     The rotary cylinder  40 , which is molded from a plastic material, carries a plurality of hair pinching row units  50  which are evenly spaced around the circumference of the cylinder. As best shown in FIGS. 4 to  7 , each row unit  50  includes four stationary blades  61  which are aligned along the axis of the cylinder, four movable blades  71  which alternate the stationary blades, and three skin guides  80  interposed between the adjacent stationary blades  61 . These members are commonly supported to a single metal-made holder plate  90  to define a self-sustained sub-assembly which is easily fitted around the cylinder  40 . The movable blades  71  are caused to pivot about an axis perpendicular to the longitudinal axis of the rotary cylinder  40  to open and close the gap between the adjacent blades  61  and  71  as the rotary cylinder  40  rotates about the longitudinal axis, thereby catching and pinching the hairs between the blades. The closure of the blades  61  and  71  are kept over a certain angular displacement around the longitudinal axis, i.e., a fraction of one rotation of the rotary cylinder  40 , thereby pulling the hairs pinched between the blades  61  and  71  in a tangential direction of the cylinder  40  for plucking the hairs. 
     As shown in FIG. 6, the two stationary blades  61  are shaped from a metal plate into an integrated piece  60  in which the blades  61  are inseparably continuous with one another through a pair of beams  62 . The skin guide  80  is molded from a plastic material to have an arcuate surface  81  on its top for smooth contact with the skin of the user, and an anchor stud  84  which projects to be press-fitted into a corresponding hole  91  of the holder plate  90  by the use of resiliency inherently given to the molded part. Formed at the opposite side of the skin guide  80  are grips  85  which presses the beams  62  of the integrated piece  60  against the holder plate  90  so as to secure the stationary blades  61  to the holder plate at the same time as the skin guide  80  is secured to the plate. The movable blade  71  is made of a metal and has a leg  72  of which lower end is inserted into a corresponding slot  92  of the plate  90  so that the leg comes into edge-contact selectively with either one of the opposite edges of the slot  92 . Formed on opposite of the leg are round projections  73  which cam over inclines of hooks  86  on the skin guide  80  and are retained loosely behind the hooks  86 . Whereby, the movable blades  71  can be pivotally supported to the holder plate  90  and complete the self-sustained sub-assembly which can be handled as one block when assembling the pinching row units into the rotary cylinder  40 . Two integrated pieces  60 , i.e., four stationary blades  61 , four movable blades  71 , and three skin guides  80  are supported to one holder plate  10  to constitute each one of the plural pinching row units  50 . After the row units  50  are placed in corresponding grooves  42  of the rotary cylinder  40 , a corresponding number of pins  51  are inserted into the cylinder with each pin extending through the stationary blades  61 , the movable blades  71 , and the skin guides  80  to hold the row units in position where, as best shown in FIG. 4, the movable blades  71  are linked to actuator bars  101  and  102  which are inserted in the rotary cylinder  40  for imparting the pivotal movement to the movable blades  71  for closing and opening the gap between the blades  61  and  71 . 
     The actuator bars  101  and  102  are provided in number double the number of the row units  50 , i.e., eight bars in each longitudinal half of the cylinder  40  so that each bar is linked to actuate the two adjacent movable blades  71  in each one of the row units  50 , as shown in FIGS. 2 and 4. That is, each actuator bar is linked to actuate the two movable blades  71  simultaneously to open and close in association with the two stationary blades  61  of each integrated piece  60 . Thus, the two movable blades  71  pivot simultaneously in the same direction for making closing and opening movements relative to the two stationary blades  61  common to the single integrated piece  60 , i.e., two stationary blades having dimensional stability with respect to one another, thereby facilitating to achieve uniform hair pinching effects at the stationary blades, in addition to achieving a strong pinching effect by the use of metal-made blades  61  and  71 . In addition, the beams  62  merge into legs  63  of reduced width which is formed at the lower end of each stationary blade  61  to be resiliently deformable to some extent for absorbing an excessive stress applied from the counterpart movable blade  71 . With this capability of absorbing the excessive stress, it is possible to balance the pinching forced developed at the two stationary blades  61  of the integrated piece  60 , even if the movable blades  71  should be pressed differently. The actuator bars  101  and  102  are held in the bottom of the groove  42  of the row unit  50  to be axially slidable and are caused to move axially inwardly by the action of cam rollers  110  as the cylinder  40  rotates and to move axially outwardly by the action of return springs  120  as the cylinder  40  further rotates, thereby repeating to close and open the blades during one rotation of the cylinder. 
     The actuator bars  101  and  102  are each formed at its axially outer end with an arcuate flange  103 ,  104  which extends circumferentially about the longitudinal axis of the cylinder  40  for pressed contact with the corresponding cam roller  110  over a prolonged period as the cylinder  40  rotates. As best shown in FIGS. 5 and 7, the actuator bars  101  and  102  consist of two types having different configurations, a first type having the arcuate flange  103  offset radially outwardly relative to a shank of the bar, and a second type having the arcuate flange  104  generally aligned with the shank of the bar. The first and second types of the actuator bars  101  and  102  are arranged in such a manner that, as shown in FIG. 5, the arcuate flanges  103  of the first type are closely arranged along an outer circumferential row about the longitudinal axis of the cylinder  40 , while the arcuate flanges  104  of the second type are closely arranged along an inner circumferential row about the longitudinal axis. Further, the arcuate flanges  103  in the outer circumferential row are staggered circumferentially with respect to the arcuate flanges  104  of the inner circumferential row such that each arcuate flange  103  is radially overlapped with the two adjacent arcuate flanges  104  by a certain circumferential. It is noted that the cam roller  110  has an axial length so that it contacts simultaneously with the arcuate flanges  103  and  104  of the outer and inner circumferential rows, respectively. Thus, as the cylinder  40  rotates, the movable blades  71  in two or three adjacent row units  50  of the cylinder  40  are simultaneously closed, while the movable blades  71  in the other row units are opened. With this result, the movable blades  71  in each row are kept closed over a prolonged period as the cylinder rotates for successful hair plucking, while enabling to provide a large number of the row units around the circumference of the cylinder  40  of a limited diameter. As shown in FIGS. 2 and 3, the cam rollers  110  are mounted respectively in holes  111  of the head frame  35  and are rotatable about individual pins  112 . Each cam roller is pressed inwardly against the actuator bar  101 ,  102  by spring props  113  secured to the head frame  35 . 
     The return springs  120  are provided on opposite ends of the cylinder  40  for biasing the actuator bars  101  and  102  axially outwardly with one spring responsible for the eight actuator bars having the arcuate flanges  103  and  104  disposed on one end of the cylinder, and the other spring for the remaining eight actuator bars having the arcuate flanges  103  and  104  on the other end of the cylinder  40 . That is, one return spring  120  is commonly used for urging the plural actuator bars in a direction of pivoting the movable blades  71  of the plural row units  50  away from the associated stationary blades  61 . As shown in FIGS. 8 and 9, the return spring  120  is a one-piece member which is stamped from a resilient metal sheet into a star-shaped to have four spring arms  124  extending radially from a center hub  121  which is secured to the rotary cylinder  40 . The center hub  121  has an opening  122  so as to be fitted around a center post  44  of the rotary cylinder  40  through which the axle  36  extends, and is fixedly secured thereto by engagement of bites  123  into the post. The spring arm  124  is of a generally U-shaped to have a first radial segment  125  extending outwardly from the center hub  121 , an arc segment  126  extending from the outer end of the first radial segment  125 , and a second radial segment  127  extending radially inwardly from the end of the arc segment  126 . It is this second radial segment  127  that is pressed against the arcuate flanges  103  and  104  of the two circumferentially adjacent actuator bars  101  and  102 , as best shown in FIG. 10, for biasing the movable blades  71  carried by the actuator bars away from the associated stationary blades  61 . Thus, the spring arm  124  can have an effective spring length within a limited radius of the return spring so as to develop a sufficient spring force for successfully returning the movable blades to the open condition. Further, the spring arms  124  extend from the hub  121  in a spiral fashion about the center axis of the spring, i.e., the longitudinal axis of the cylinder  40 , thereby further increasing the biasing force at a limited diameter of the return spring  120 . In this connection, the return spring  120  is secured to the cylinder  40  with the individual spring arms  124  spirally extending axially outwardly of the cylinder for pressed contact with the corresponding arcuate flanges  103  and  104  of the actuators  101  and  102 . 
     Returning back to FIG. 5, each of the arcuate flanges  103  and  104  is formed at its opposite ends with receding slant faces and  105  so that each arcuate flange comes into contact with the cam roller  110  by way of the slant face and out of contact therefrom also by way of the slant face, thereby reducing an impact at the time of closing and opening the blades and therefore assuring a reduced-in-noise hair plucking. 
     As shown in FIGS. 5 and 6, the stationary blade  61  and the associated movable blade  71  are formed at their one ends facing toward the rotating direction of the cylinder  40  with flared edges  64  and  74  which are cooperative to define therebetween a tapered groove for effectively guiding the hairs into between the blades. The rotary cylinder  40  is formed at its opposite axial ends with reduced-in-width sections  46  of uniform radius which defines an overall circular circumference of the rotary cylinder. As shown in FIG. 11, the stationary blades  61 , the movable blades  71 , and the skin guides  80  are arranged within the circumference X of the cylinder  40  in such a manner that each of the stationary blade  61  and movable blade  71  has its opposite circumferential end inscribed in the circumference, and that the arcuate surface  81  of the skin guide  80  has its middle portion inscribed in the circumference. The leading and the trailing edges of each of the stationary blades  61 , movable blades  71 , and the arcuate surfaces of the skin guides  80  are rounded in order to avoid irritating the skin. Particularly, the arcuate surface of the skin guide  80  has its leading and trailing edges  82  and  83  shaped to be smoothly continuous with the remainder of the arcuate surface and to have a curvature greater than that of the remainder arcuate surface. 
     As shown in FIG. 12, the row units  50  are arranged on the cylinder  40  as being offset in the axial direction relative to each other so that the pairs of the stationary blade  61  and the movable blade  71  in anyone of the row units are staggered with the other pairs of the other row units with respect to the longitudinal axis of the cylinder, so that all the blade pairs are differently positioned with respect to the longitudinal axis of the cylinder for maximum plucking efficiency. 
     FIG. 13 shows a rotary cylinder  40 A employed in an epilating device in accordance with another preferred embodiment of the present invention which is identical to the above embodiment except for the configurations of the pinching row unit and the associated actuator bars  101 A and  102 A. Therefore, like parts are designated by like reference numerals with a suffix letter of ‘A’. Each of the pinching row units  50 A which are evenly spaced around the rotary cylinder  40 A has only one set of movable blades  71 A which are driven to move against and away from one another for catching the hairs therebetween. As shown in FIG. 14, the movable blades  71 A are retained to a holder plate  90 A together with skin guides  80 A in the same manner as in the previous embodiment, and are capable of pivoting about an axis perpendicular to the longitudinal axis of the cylinder. That is, the skin guides are press-fitted to holes  91 A of the holder plate  90 A, and the movable blade  71 A is loosely coupled to the adjacent skin guide  80 A by engagement of round projections  73 A with hooks  86 A of the skin guide  80 A. The movable blade  71 A extends through a slot  92 A of the plate and comes into edge contact with the edge of the slot to make the pivot movement when driven by corresponding actuator bars  101 A and  102 A. 
     The rotary cylinder carries plural sets of actuator bars  101 A and  102 A which are arranged circumferentially about the longitudinal axis of the cylinder in much the same way as in the previous embodiment. The actuator bars  101 A ( 102 A) in each set are axially aligned and are connected respectively to the movable blades  71 A in each pinching row unit  50 A so as to pivot the blades in a direction of closing the blades when the actuator bars  101 A ( 102 A) are driven by cam rollers  110 A to shift axially inwardly as shown in the top part of FIG. 13, and to pivot the blades in a direction of opening the same when the actuator bars  101 A ( 102 A) are urged by a return spring  120  to shift axially outwardly as shown in the bottom part of FIG.  13 . The return spring  120  are of exactly the same configuration as shown in FIGS. 8 and 9. Formed at the inner end of each actuator bar is a stepped section  108  of reduced thickness which includes a slit  109  for connection with the movable blade, as best shown in FIG.  15 . The actuator bars in each set are assembled to the rotary cylinder in such a manner as to overlap the stepped sections  108 , thereby enabling to pivoting the blades successfully. 
     As shown in FIG. 16, the pinching row units  50 A are spaced evenly around the rotary cylinder  40 A and at the same offset from each other with respect to the lengthwise or axial direction of the cylinder so as to cover a wide hair plucking area per one rotation of the cylinder. 
     Although the above description illustrates typical structures of the pinching row unit, it should be noted that the present invention can equally applied to pinching row of different structures. For example, the pinching row may include at least one blade set in which two movable blades are disposed on opposite of a single stationary blade and are driven by the corresponding actuator bars to pivot against and away from the stationary blade. In any case, a set of circumferentially arranged actuator bars provided for a plurality of the circumferentially arranged pinching row units are commonly coupled to one return spring. Further, the set of blades in each pinching row unit is offset from the set of blades in any other pinching row unit for maximum hair plucking efficiency within a length of the cylinder.