Patent Description:
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 <NUM>: <CIT>). 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 <NUM>: <CIT>).

PTL <NUM> discloses a dry-shaving apparatus comprising cutting elements which comprise a central bearing member.

PTL <NUM> discloses a shaving apparatus having a skin contact surface accommodating at least one cutting unit.

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 <NUM>, 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 <NUM> has many manufacturing problems. In the configuration disclosed in PTL <NUM> 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.

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 two to six balls in an outer blade part, and an inner blade member can safely rotate so that the balls are 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 according to claim <NUM>.

According to this configuration, the following configuration can be adopted. A part of each of the two to six balls supported by the disk-shaped cover disposed at an inner position of an annular part and the support protrudes from the cover, and each of the two to six balls comes into contact with skin so that a user feels a smooth sense of the touch on the skin during shaving. That is, each of the two to six balls is supported while it 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 two to six balls is likely to rotate by reducing frictional resistance.

The number of the balls disposed in each of the outer blade parts is two to six. All of the two to six 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 two to six 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 plurality of ball receiving holes corresponding to the two to six balls 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 each ball receiving hole, and each of the claw parts is in contact with one of the two to six balls. 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 each ball and the support can be reduced as much as possible by the claw parts. Accordingly, a structure can be provided so that each ball is more likely to rotate.

It is preferable that in each 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, each 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, each 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 two to six balls from below. In this manner, each of the two to six balls rolls. Accordingly, the two to six balls 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, groove parts having a depth which allows swing movement of the blade unit are formed at an intermediate position between adjacent blade units. 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 two to six balls. 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.

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 two to six balls in an outer blade part, and an inner blade member can safely rotate so that the two to six balls are likely to rotate.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the drawings. A rotary electric shaver <NUM> of the present embodiment has a head <NUM> having a plurality of blade units <NUM>. As illustrated in <FIG>, as an example, the rotary electric shaver <NUM> includes a grip part <NUM> gripped by a user, and the head <NUM> detachably connected to a connection part <NUM> disposed in the grip part <NUM>. A front surface side of a main body <NUM> is an operation panel, and a power switch <NUM> is disposed. As an example, a blade setting base <NUM> is connected to the grip part <NUM> via the connection part <NUM>, and the head <NUM> is configured to be capable of tilting with respect to the main body <NUM>. Here, in order to easily describe a positional relationship of each part of the rotary electric shaver <NUM>, directions are indicated by arrows X, Y, and Z in the drawing. When the rotary electric shaver <NUM> is actually used, without being limited to the directions, the rotary electric shaver <NUM> 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 <FIG>, as an example, the main body <NUM> has the grip part <NUM> and the blade setting base <NUM>, and a trimmer <NUM> is disposed on a back surface side of the main body <NUM>. A motor <NUM>, a battery <NUM> which can supply a direct current to the motor <NUM>, and a controller <NUM> activated by the power switch <NUM> are built in the grip part <NUM> in the main body <NUM>. As an example, a configuration is adopted as follows. A power supply terminal <NUM> is disposed in a lower part on the back surface side of the main body <NUM>, and power can be supplied to the battery <NUM> from an external power source via the power supply terminal <NUM>. As an example, the motor <NUM> is connected to a first driven shaft <NUM> by a first drive part <NUM> having a plurality of gears. A technique in the related art can be applied to the first drive part <NUM>. A plurality of second driven shafts <NUM> are disposed in the blade setting base <NUM>. As an example, three second driven shafts <NUM> are disposed at a predetermined interval. As an example, the first driven shaft <NUM> is connected to the second driven shaft <NUM> by a second drive part <NUM> having a plurality of gears. A technique in the related art can be applied to the second drive part <NUM>.

The head <NUM> has a setting part <NUM> having a plurality of blade units <NUM>, and a blade frame <NUM> that holds the setting part <NUM>. As an example, three blade units <NUM> are disposed at a predetermined interval in the head <NUM>. In the setting part <NUM>, each groove part 6a having a depth which allows swing movement of the blade unit <NUM> is formed at an intermediate position between the blade unit <NUM> and the blade unit <NUM>. In a configuration in which the three blade units <NUM> are disposed, three groove parts 6a are formed, and one end of each of the groove parts 6a is connected in a center of the setting part <NUM>. The setting part <NUM> is configured as follows. The setting part <NUM> is pressed up due to a restoring force of a plate-shaped spring <NUM> disposed in the blade frame <NUM>.

<FIG> is an enlarged view of a part of the head <NUM> in <FIG> which is surrounded by a broken line E. <FIG> is a schematic structural development view of the head <NUM>. <FIG> is a perspective view of a cover <NUM> in the head <NUM>. <FIG> is a perspective view of a support <NUM> in the head <NUM>. <FIG> is a perspective view of an outer blade member <NUM> in the head <NUM>. <FIG> is a perspective view of an inner blade part <NUM> in the head <NUM>. An outer blade part <NUM> is configured to have the annular outer blade member <NUM>, the disk-shaped cover <NUM>, a plurality of balls <NUM>, and the support <NUM>.

Each of the blade units <NUM> has the outer blade part <NUM> and the inner blade part <NUM>. The outer blade part <NUM> has an outer shaving surface 31a and an inner sliding contact surface 31b with which a blade edge 9a comes into sliding contact, and has the annular and metal-made outer blade member <NUM> in which a plurality of slits 31c 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 <NUM> has a metal-made inner blade member <NUM> in which a plurality of the blade edges 9a are formed in the circumferential direction, and a resin-made base part <NUM> joined to the inner blade member <NUM>. A first projection part 22d is formed in a center of the base part <NUM>, and a first hollow part 22e is formed inside the first projection part 22d. A tip part of the second driven shaft <NUM> is fitted to the first hollow part 22e, the second driven shaft <NUM> is connected to the base part <NUM>, and the inner blade member <NUM> is configured to rotate around an axis P1 of the second driven shaft <NUM>. A technique in the related art can be applied to the outer blade part <NUM> and the inner blade part <NUM>.

The disk-shaped and resin-made cover <NUM> is disposed inside the annular outer blade member <NUM>. The cover <NUM> has a plurality of circular windows 32a each having a smaller diameter than the corresponding ball in the plurality of balls <NUM>, and has a plurality of pins 32b which are formed to protrude.

A plurality of the balls <NUM> are disposed in each of the outer blade members <NUM>. As an example, three balls <NUM> are disposed at positions deviated from the axis P1 of the second driven shaft <NUM>. As an example, the plurality of balls <NUM> are 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 balls <NUM> can be colored by means of plating or by using an anodic oxide film, for example. The plurality of balls <NUM> can be made of a resin or ceramics.

A second projection part 34d is formed in the center of the disk-shaped and resin-made support <NUM>, and a plurality of through holes 34a into which the pins 32b are inserted are formed around the second projection part 34d. As an example, the through hole 34a is set to have a hole diameter which enables the pin 32b to be fitted in a state where the pin 32b is inserted into the through hole 34a. The support <NUM> has a plurality of ball receiving holes 34b corresponding to the plurality of balls <NUM> on a one-to-one basis. The support <NUM> has a plurality of claw parts 34c protruding from an inner peripheral side of each ball receiving hole 34b at an equal interval in the circumferential direction. Each of the claw parts 34c is in contact with one of the plurality of balls <NUM> to support the ball <NUM> from below. As an example, the number of the disposed claw parts 34c is three to five. The cover <NUM> is fitted and assembled to the support <NUM> in a state where each of the balls <NUM> is supported from below. A part of each ball <NUM> surrounded by the cover <NUM> and the support <NUM> is configured to protrude from the window 32a.

Each ball receiving hole 34b has discharge parts 34f respectively formed on both sides of each of the claw parts 34c. In this manner, even when a shaving waste enters the inside through a gap formed around the ball <NUM> when the ball <NUM> is operated in an upward-downward direction, the entering shaving waste passes through the discharge part 34f, passes through the inner blade part <NUM>, 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 <NUM>. In addition, each of the discharge parts 34f has a shape in which a position between the claw parts 34c and the claw parts 34c which are disposed adjacent to each other in the circumferential direction is enlarged. Accordingly, the claw part 34c can have a shape which is likely to follow an operation in the upward-downward direction of the ball <NUM>.

The second projection part 34d is formed in the center of the disk-shaped and resin-made support <NUM>, and a second hollow part 34e is formed inside the second projection part 34d. The first projection part 22d is fitted to the second hollow part 34e, and the cover <NUM> and the support <NUM> are configured to rotate around the axis P1 of the second driven shaft <NUM> in conjunction with rotation of the inner blade member <NUM>.

According to the present invention the rotary electric shaver <NUM> is described in claim <NUM>.

The rotary electric shaver <NUM> achieves excellent shaving performance even in a largely undulating area from a chin to a face.

Claim 1:
A rotary electric shaver (<NUM>), comprising:
a main body (<NUM>) having a grip part (<NUM>) and a blade setting base (<NUM>);
a motor (<NUM>) built in the main body (<NUM>) and connected to a first driven shaft (<NUM>); and
a head (<NUM>) connected to the blade setting base (<NUM>),
wherein in the blade setting base (<NUM>), a plurality of second driven shafts (<NUM>) are connected to the first driven shaft (<NUM>),
the head (<NUM>) has a setting part (<NUM>) in which a plurality of blade units (<NUM>) are disposed, and a blade frame (<NUM>) that holds the setting part (<NUM>),
each of the blade units (<NUM>) has an outer blade part (<NUM>) and an inner blade part (<NUM>),
the inner blade part (<NUM>) has an inner blade member (<NUM>) in which a plurality of blade edges (9a) are formed in a circumferential direction, and a base part (<NUM>) joined to the inner blade member (<NUM>),
the second driven shaft (<NUM>) is connected to the base part (<NUM>), and the inner blade member (<NUM>) is configured to rotate around an axis (P1) passing through the second driven shaft (<NUM>),
the outer blade part (<NUM>) has an annular outer blade member having a sliding contact surface with which the blade edge (9a) comes into sliding contact and having a plurality of slits formed in the circumferential direction, a disk-shaped cover (<NUM>) disposed inside the annular outer blade member, two to six balls (<NUM>) disposed in the outer blade part (<NUM>), and a support (<NUM>) that supports the two to six balls (<NUM>),
the cover (<NUM>) has two to six windows (32a), wherein
a part of each of the two to six balls (<NUM>) surrounded by the cover (<NUM>) and the support (<NUM>) protrudes from a corresponding window (32a) of the two to six windows, and wherein
each of the two to six windows (32a) has a smaller diameter than the corresponding ball in the two to six balls (<NUM>), and
all of the two to six balls are disposed at positions deviated from the axis (P1) passing through the second driven shaft (<NUM>).