Patent Publication Number: US-2023132864-A1

Title: Rotary electric shaver

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. P2021-176037, filed on Oct. 28, 2021, and the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to a rotary electric shaver. 
     BACKGROUND ART 
     In the related art, with regard to a rotary electric shaver configured to include one blade unit having an outer blade whose outer side has a circular shaving surface and an inner blade which rotates while coming into sliding contact with an inner surface of the outer blade, a configuration has been proposed in which a total of nine balls are fitted into one location on a central axis of the outer blade and eight locations in a circumferential direction on an outer peripheral part of the outer blade so that a part of each of the balls protrudes (PTL 1: JP-UM-A-61-140767). In the related art, a rotary electric shaver having the following configuration is known. A plurality of blade units having an outer blade whose outer side has an annular shaving surface and an inner blade which rotates while coming into sliding contact with an inner surface of the outer blade are disposed (PTL 2: JP-A-2015-070927). 
     CITATION LIST 
     Patent Literature 
     
         
         PTL 1: JP-UM-A-61-140767 
         PTL 2: JP-A-2015-070927 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     A rotary electric shaver has the following advantage. When a ball is disposed on a contact surface with skin in a head part, the ball comes into contact with the skin so that a user feels a smooth sense of touch on the skin during shaving. However, in the configuration disclosed in PTL 1, a position where a ball receiving member is welded to a minute part of the outer blade is fixed. Consequently, the ball attached to the ball receiving member is likely to be in a biased state. Since the ball is biased, frictional resistance increases, and the ball is brought into a state where the ball is less likely to rotate. In addition, the ball is fitted into the ball receiving member from an outside of the outer blade, thereby causing a possibility that the outer blade may deform depending on adjustment of a fitting force. Furthermore, collision between the inner blade and the ball receiving member needs to be avoided. Accordingly, the inner blade adopts a special shape. In this way, the configuration disclosed in PTL 1 has many manufacturing problems. In the configuration disclosed in PTL 2 in which the plurality of blade units are disposed, compared to the configuration having one blade unit, it becomes more difficult to dispose the ball on the contact surface with the skin in the head part. 
     Solution to Problem 
     The present invention is made in view of the above-described circumstances, and an object of the present invention is to provide a rotary electric shaver having the following structure. In a configuration in which a plurality of blade units are disposed, a user feels a smooth sense of touch on skin by disposing a ball in an outer blade part, and an inner blade member can safely rotate so that the ball is likely to rotate. 
     The present invention has been accomplished under the solutions as disclosed below. 
     According to the present invention, there is provided a rotary electric shaver including a main body having a grip part and a blade setting base, a motor built in the main body and connected to a first driven shaft, and a head connected to the blade setting base. In the blade setting base, a plurality of second driven shafts are connected to the first driven shaft. The head has a setting part in which a plurality of blade units are disposed, and a blade frame that holds the setting part. Each of the blade units has an outer blade part and an inner blade part. The inner blade part has an inner blade member in which a plurality of blade edges are formed in a circumferential direction, and a base part joined to the inner blade member. The second driven shaft is connected to the base part, and is configured to rotate around an axis passing through the second driven shaft. The outer blade part has an annular outer blade member having a sliding contact surface with which the blade edge comes into sliding contact and having a plurality of slits formed in the circumferential direction, a disk-shaped cover disposed inside the outer blade member, a ball, and a support that supports the ball. The cover has a window having a smaller diameter than the ball. A part of the ball surrounded by the cover and the support protrudes from the window. 
     According to this configuration, the following configuration can be adopted. A part of the ball supported by the disk-shaped cover disposed at an inner position of an annular part and the support protrudes from the cover, and the ball comes into contact with skin so that a user feels a smooth sense of the touch on the skin during shaving. That is, the ball is supported while the ball is surrounded by the cover and the support. In this manner, while a configuration is adopted so that the inner blade member can safely rotate, a structure can be provided so that the ball is likely to rotate by reducing frictional resistance. 
     As an example, the number of the balls disposed in each of the outer blades is one or larger. As an example, the number of the balls disposed in each of the outer blades is six or smaller. It is preferable that the number of the balls disposed in each of the outer blade parts is two to six, and all of the balls are disposed at positions deviated from the axis of the second driven shaft. In this manner, a size of the outer blade can be easily reduced to such an extent that the outer blade does not interfere with the second driven shaft. Since the plurality of balls which are small to such an extent that the balls do not interfere with shaving are disposed, a user feels a smoother sense of the touch on the skin. 
     It is preferable that the support has a ball receiving hole corresponding to the ball on a one-to-one basis and a plurality of claw parts formed at an equal interval in the circumferential direction to protrude from an inner peripheral side of the ball receiving hole, and the claw part is in contact with the ball. In this manner, while the balls are supported from below by the claw parts formed at the equal interval in the circumferential direction, a contact area between the ball and the support can be reduced as much as possible by the claw parts. Accordingly, a structure can be provided so that the ball is more likely to rotate. 
     It is preferable that in the ball receiving hole, discharge parts are respectively formed on both sides of each of the claw parts. In this manner, even when a shaving waste enters the inside through a gap formed around the ball when the ball is operated in an upward-downward direction, the entering shaving waste passes through the discharge part, passes through the inner blade part, and is collected in a lower shaving waste discharge area. Accordingly, it is possible to prevent accumulation of the shaving waste which hinders an operation of the ball. 
     As an example, the ball may be made of metal. As an example, both the cover and the support may be made of a resin. The cover may be formed so that a plurality of pins protrude. It is preferable that the support has a plurality of through holes into which the pins are inserted, respectively, and the cover is fitted and assembled to the support. In this manner, the cover and the support can be positioned and fitted to each other. Accordingly, the ball can be easily positioned. 
     A first projection part may be formed in a center of the base part, and a first hollow part may be formed inside the first projection part. A second projection part may be formed in a center of the support, and the second hollow part may be formed inside the second projection part. It is preferable that the second driven shaft is fitted to the first hollow part, and the first projection part is fitted to the second hollow part. In this manner, the support rotates in conjunction with the second driven shaft while supporting the ball from below. In this manner, the ball rolls. Accordingly, the ball can be positively rotated. 
     As an example, the number of the disposed blade units is two to six. Three blade units may be disposed in the head. It is preferable that in the setting part, each groove part having a depth which allows swing movement of the blade unit is formed at an intermediate position between the blade unit and the blade unit. In this manner, the three blade units oscillate in accordance with undulations of the skin and come into close contact with the skin. Accordingly, shaving performance can be improved, and an advantageous effect can be expected in that blood circulation is improved by massaging the skin with the ball. It is preferable that the blade setting base is connected to the grip part via a connection part, and the head is capable of tilting with respect to the main body. In this manner, excellent shaving performance is achieved even in a largely undulating area from a chin to a face. 
     Advantageous Effects of Invention 
     According to the present invention, it is possible to realize a rotary electric shaver having the following structure. In a configuration in which a plurality of blade units are disposed, a user feels a smooth sense of touch on skin by disposing a ball in an outer blade part, and an inner blade member can safely rotate so that the ball is likely to rotate. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic perspective view illustrating an example of a rotary electric shaver according to an embodiment of the present invention. 
         FIG.  2    is a schematic side view of the rotary electric shaver illustrated in  FIG.  1   . 
         FIG.  3    is a schematic vertical sectional view of the rotary electric shaver illustrated in  FIG.  2   . 
         FIG.  4    is an enlarged view of a part surrounded by a broken line in  FIG.  3   . 
         FIG.  5    is a schematic structural development view of a head according to the present embodiment. 
         FIG.  6 A  is a schematic perspective view of a cover,  FIG.  6 B  is a schematic perspective view of a support,  FIG.  6 C  is a schematic perspective view of an outer blade member, and  FIG.  6 D  is a schematic perspective view of an inner blade part. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment according to the present invention will be described in detail with reference to the drawings. A rotary electric shaver  1  of the present embodiment has a head  4  having a plurality of blade units  5 . As illustrated in  FIG.  1   , as an example, the rotary electric shaver  1  includes a grip part  15  gripped by a user, and the head  4  detachably connected to a connection part  13  disposed in the grip part  15 . A front surface side of a main body  2  is an operation panel, and a power switch  53  is disposed. As an example, a blade setting base  3  is connected to the grip part  15  via the connection part  13 , and the head  4  is configured to be capable of tilting with respect to the main body  2 . Here, in order to easily describe a positional relationship of each part of the rotary electric shaver  1 , directions are indicated by arrows X, Y, and Z in the drawing. When the rotary electric shaver  1  is actually used, without being limited to the directions, the rotary electric shaver  1  may be used in any desired direction. In all drawings for describing the embodiment, the same reference numerals will be assigned to members having the same function, and repeated description thereof may be omitted in some cases. 
     As illustrated in  FIGS.  1  to  3   , as an example, the main body  2  has the grip part  15  and the blade setting base  3 , and a trimmer  54  is disposed on a back surface side of the main body  2 . A motor  51 , a battery  52  which can supply a direct current to the motor  51 , and a controller  55  activated by the power switch  53  are built in the grip part  15  in the main body  2 . As an example, a configuration is adopted as follows. A power supply terminal  58  is disposed in a lower part on the back surface side of the main body  2 , and power can be supplied to the battery  52  from an external power source via the power supply terminal  58 . As an example, the motor  51  is connected to a first driven shaft  11  by a first drive part  56  having a plurality of gears. A technique in the related art can be applied to the first drive part  56 . A plurality of second driven shafts  12  are disposed in the blade setting base  3 . As an example, three second driven shafts  12  are disposed at a predetermined interval. As an example, the first driven shaft  11  is connected to the second driven shaft  12  by a second drive part  57  having a plurality of gears. A technique in the related art can be applied to the second drive part  57 . 
     The head  4  has a setting part  6  having a plurality of blade units  5 , and a blade frame  7  that holds the setting part  6 . As an example, three blade units  5  are disposed at a predetermined interval in the head  4 . In the setting part  6 , each groove part  6   a  having a depth which allows swing movement of the blade unit  5  is formed at an intermediate position between the blade unit  5  and the blade unit  5 . In a configuration in which the three blade units  5  are disposed, three groove parts  6   a  are formed, and one end of each of the groove parts  6   a  is connected in a center of the setting part  6 . The setting part  6  is configured as follows. The setting part  6  is pressed up due to a restoring force of a plate-shaped spring  41  disposed in the blade frame  7 . 
       FIG.  4    is an enlarged view of a part of the head  4  in  FIG.  3    which is surrounded by a broken line E.  FIG.  5    is a schematic structural development view of the head  4 .  FIG.  6 A  is a perspective view of a cover  32  in the head  4 .  FIG.  6 B  is a perspective view of a support  34  in the head  4 .  FIG.  6 C  is a perspective view of an outer blade member  31  in the head  4 .  FIG.  6 D  is a perspective view of an inner blade part  9  in the head  4 . An outer blade part  8  is configured to have the annular outer blade member  31 , the disk-shaped cover  32 , a ball  33 , and the support  34 . 
     Each of the blade units  5  has the outer blade part  8  and the inner blade part  9 . The outer blade part  8  has an outer shaving surface  31   a  and an inner sliding contact surface  31   b  with which a blade edge  9   a  comes into sliding contact, and has the annular and metal-made outer blade member  31  in which a plurality of slits  31   c  having a size which enables hairs to enter are formed in the circumferential direction. In this invention, examples of the hairs include beards, mustache, whisker, and the like. The inner blade part  9  has a metal-made inner blade member  21  in which a plurality of the blade edges  9   a  are formed in the circumferential direction, and a resin-made base part  22  joined to the inner blade member  21 . A first projection part  22   d  is formed in a center of the base part  22 , and a first hollow part  22   e  is formed inside the first projection part  22   d . A tip part of the second driven shaft  12  is fitted to the first hollow part  22   e , the second driven shaft  12  is connected to the base part  22 , and the inner blade member  21  is configured to rotate around an axis P 1  of the second driven shaft  12 . A technique in the related art can be applied to the outer blade part  8  and the inner blade part  9 . 
     The disk-shaped and resin-made cover  32  is disposed inside the annular outer blade member  31 . The cover  32  has a plurality of circular windows  32   a  having a smaller diameter than the ball  33 , and has a plurality of pins  32   b  which are formed to protrude. 
     A plurality of the balls  33  are disposed in each of the outer blade members  31 . As an example, three balls  33  are disposed at positions deviated from the axis P 1  of the second driven shaft  12 . As an example, the ball  33  is made of metal, and is made of stainless steel, aluminum, steel, titanium, a copper alloy, a nickel alloy, or other known metal or alloys. A surface of the ball  33  can be colored by means of plating or by using an anodic oxide film, for example. The ball  33  can be made of a resin or ceramics. 
     A second projection part  34   d  is formed in the center of the disk-shaped and resin-made support  34 , and a plurality of through holes  34   a  into which the pins  32   b  are inserted are formed around the second projection part  34   d . As an example, the through hole  34   a  is set to have a hole diameter which enables the pin  32   b  to be fitted in a state where the pin  32   b  is inserted into the through hole  34   a . The support  34  has a ball receiving hole  34   b  corresponding to the ball  33  on a one-to-one basis. The support  34  has a plurality of claw parts  34   c  protruding from an inner peripheral side of the ball receiving hole  34   b  at an equal interval in the circumferential direction. Each of the claw parts  34   c  is in contact with the ball  33  to support the ball  33  from below. As an example, the number of the disposed claw parts  34   c  is three to five. The cover  32  is fitted and assembled to the support  34  in a state where each of the balls  33  is supported from below. A part of the ball  33  surrounded by the cover  32  and the support  34  is configured to protrude from the window  32   a.    
     The ball receiving hole  34   b  has discharge parts  34   f  respectively formed on both sides of each of the claw parts  34   c . In this manner, even when a shaving waste enters the inside through a gap formed around the ball  33  when the ball  33  is operated in an upward-downward direction, the entering shaving waste passes through the discharge part  34   f , passes through the inner blade part  9 , and is collected in a lower shaving waste discharge area. Accordingly, it is possible to prevent accumulation of the shaving waste which hinders an operation of the ball  33 . In addition, each of the discharge parts  34   f  has a shape in which a position between the claw parts  34   c  and the claw parts  34   c  which are disposed adjacent to each other in the circumferential direction is enlarged. Accordingly, the claw part  34   c  can have a shape which is likely to follow an operation in the upward-downward direction of the ball  33 . 
     The second projection part  34   d  is formed in the center of the disk-shaped and resin-made support  34 , and a second hollow part  34   e  is formed inside the second projection part  34   d . The first projection part  22   d  is fitted to the second hollow part  34   e , and the cover  32  and the support  34  are configured to rotate around the axis P 1  of the second driven shaft  12  in conjunction with rotation of the inner blade member  21 . 
     According to the present embodiment, the present invention realizes the rotary electric shaver  1  having the following structure. In a configuration in which the plurality of blade units  5  are disposed in the head  4 , a user feels a smooth sense of touch on the skin by disposing the ball  33  in the outer blade part  8 , and the inner blade member  21  can safely rotate so that the ball  33  is likely to rotate. In addition, the cover  32  and the support  34  rotate while supporting the ball  33 . In this manner, the ball  33  rolls. Accordingly, the ball  33  can be positively rotated. The rotary electric shaver  1  achieves excellent shaving performance even in a largely undulating area from a chin to a face. 
     The present invention is not limited to the embodiment described above, and various modifications can be made within the scope not departing from the present invention.