1. Field of the Invention
The present invention relates to a rotary electric shaver which rotatively drives inner cutters, which are in resilient contact with inner bottom surfaces of circular outer cutters.
2. Description of the Related Art
There has been known a so-called rotary electric shaver which has circular or disk-shaped outer cutters and inner cutter rotating on the inner side of the outer cutters so that beard hair entering the hair introduction slits formed in the outer cutters is cut by the rotating inner cutters. As this type of electric shaver, there has been known in which outer cutter installing holes are formed in an outer cutter frame secured to a shaver main body and circular outer cutters are supported in the outer cutter installing holes such that the outer cutters are slightly movable in a vertical direction and slightly inclinable with respect to the outer cutter frame.
However, the aforesaid construction provides the outer cutters with a limited movable range relative to the outer cutter frame, thus presenting a problem in that the close contact between the outer cutters and skin is restricted with resultant unsatisfactory shaving feeling or inadequate user-friendliness. It has been proposed, therefore, to provide a rim which is movable relative to the main body (the rim being also referred to as an outer cutter rim, an cutter circumferential rim, a skin supporting rim or a skin protecting rim) between the outer cutters and the main body (the outer cutter frame) so as to expand the movable range and the inclinable range of the outer cutters.
JP 9-503424(T) (corresponding to WO 96/02368, U.S. Pat. No. 5,625,950 and EP 0719203) discloses a shaving apparatus which has a skin supporting rim (6) provided between an outer cutter and a main body (an outer cutter frame and a holder 2). The outer cutter is held by the rim such that it is slightly movable in a vertical direction and also slightly inclinable, and the outer periphery of the rim is pivotally supported by the outer cutter frame of the main body. More specifically, the rim enters a circular opening of the outer cutter frame, and a pair of projections provided on the outer periphery of the rim is engaged with the inner peripheral surface of the opening provided in the outer cutter frame. In other words, a pivotal supporting section is disposed between the outer periphery of the rim and the opening of the outer cutter frame. Further, adjoining rims are hinge-connected (e.g., by a tongue-and-groove joint). It has been required, therefore, to form the linear joint of the adjoining rims. In addition, the restoring force of an inclined rim has been imparted by an upward force of an inner cutter drive shaft or the force of restoration (the force for restoring from an inclination) of an inner cutter drive shaft to the upright position thereof.
JP 2007-151925(A) (corresponding to US 2007-124936 (A1)) discloses a shaving apparatus in which the upper surface of a shaver main body (a head bottom plate) is provided with an upright wall (a supporting section 54) surrounding a cutter circumferential rim (cutter frame 18) holding an outer cutter, and each cutter circumferential rim is independently and pivotally retained to the upright wall. In other words, the upper surface of the shaver main body (the head bottom plate) is exposed between the cutter circumferential rims.
JP 2007-117190(A) (corresponding to US 2007-089298(A1) and EP 1779983A1) discloses a shaving apparatuses in which a cutter unit (16) consisting of an assembly of an outer cutter and an inner cutter is pivotally retained in an outer cutter mounting aperture (20) formed in an outer cutter frame (18), which is openable/closable or detachable relative to a shaver main body.
JP 2007-319339(A) (corresponding to US 2007-277379(A1) and EP 1862271A1) discloses a shaving apparatus in which an outer cutter frame (20) fixed to a shaver main body is provided with an outer cutter mounting hole (22) for mounting each cutter unit (18), a slit (50) extending toward the center of the shaver main body from an outer periphery is formed between adjoining outer cutter mounting hole (22), and a portion surrounding each of outer cutters (14) partitioned by the slit (50) is inclinable or bendable.
According to the shaving apparatus disclosed in JP 9-503424(T) (corresponding to WO 96/02368, U.S. Pat. No. 5,625,950, and EP 0719203), the adjoining cutter circumferential rims (the skin supporting rims) are hinge-connected, so that the joint portion is linear, thus restricting the shapes or placements of the cutter circumferential rims.
Further, pressing or depressing one cutter circumferential rim against the skin and inclining the cutter circumferential rim on the skin causes all cutter circumferential rims to be interlockingly pressed and tilted, resulting in an increase in a pressing force (depressing start pressure or an inclination start pressure) of each cutter circumferential rim. The pressing force or the inclining start pressure is set by an upward force or a force of an inner cutter drive shaft to restore from an inclination. The contact pressure applied by the inner cutter to the outer cutter cannot be set excessively low; otherwise, the performance for shaving beard or shaving feeling would be deteriorated. For this reason, it is difficult to set the pressing force of the cutter circumferential rims to an adequately small value.
Further, according to the shaving apparatus disclosed in JP 9-503424(T) (corresponding to WO 96/02368, U.S. Pat. No. 5,625,950, and EP 0719203), the outer cutter and the rim are reset to their stationary positions by the force of the inner cutter drive shaft to restore to an upright position. Since the inner cutter drive shaft is normally vertical, the outer cutter will normally restore to a horizontal position. This presents a problem in that the inclination of the outer cutter at the stationary position cannot be arbitrarily set. There is another problem in that the inclinable range of the cutter circumferential rim is restricted.
According to the shaving apparatus disclosed in JP 2007-151925(A) (corresponding to US 2007-124936(A1)), the upright wall of the upper surface of the shaver main body is exposed between adjoining cutter circumferential rims. This causes a problem such that the head assembly becomes inevitably larger, and shaving debris or beard trimmings easily adhere to the upper surface of the shaver main body, making it difficult to remove the debris.
The shaving apparatus disclosed in JP 2007-117190(A) (corresponding to US 2007-089298(A1) and EP 1779983A1) presents a problem in that the outer cutter frame surrounding a plurality of cutter units inevitably becomes large, resulting in a large head unit. The one disclosed in JP 2007-319339(A) (corresponding to US 2007-277379(A1) and EP 1862271A1) has a drawback in that the cutter unit tilts (or bends) together with the portion partitioned by the slit of the outer cutter frame, thus restricting the movement of the outer cutter and also preventing easy cleaning.
The present invention has been accomplished under the circumstances as aforementioned, and an object thereof is to provide a rotary electric shaver which is capable of enhancing the design freedom of the shape and placement of a cutter circumferential rim, accomplishing a reduced depressing force or an inclination start pressure of an outer cutter so as to allow the outer cutter to easily trace skin irregularities thereby to improve shaving feeling, permitting arbitrary setting of the tilt of the outer cutter in its stationary position according to user preference, expanding the inclinable range of the cutter circumferential rim, permitting a reduced size of a head unit, allowing the head unit to be easily cleaned, and enhancing the design freedom of a shaver surface.
According to the present invention, the aforesaid object is achieved by a rotary electric shaver which pivotably retains a plurality of outer cutters on a head bottom plate at the top of a shaver main body and rotatively drives inner cutters while bringing the inner cutters into resilient contact with inner surfaces of the outer cutters, the rotary electric shaver comprising:
a plurality of cutter circumferential rims, each which is detachable from the shaver main body, and separately surrounds and holds each of the outer cutters;
a pivotal supporting section which pivotably retains the respective cutter circumferential rims on a pivotal axis passing the center of the respective outer cutters; and
a detachable blind cover which fills a gap between the cutter circumferential rims and which is in resilient contact, from below, with a bottom edge of the cutter circumferential rim, the bottom edge being adjacent to the center of the shaver main body.
The individual cutter circumferential rims are not joined to each other and pivotally move independently from each other, thus leading to less restriction on the shape and placement of the cutter circumferential rims. This allows the shape and placement of the cutter circumferential rims to be determined relatively freely. Hence, the shape and placement of the cutter circumferential rims or the like can be determined according to, for example, design requirements.
Depressing or tilting one cutter circumferential rim requires the application of a depressing force which is larger than the resultant force of the upward force and the force of restoration from an inclination of a single inner cutter drive shaft associated with the cutter circumferential rim and an upward restoring force of the blind cover. The restoring force of the blind cover can be set to a sufficiently small value, and therefore the depressing start pressure or an inclination start pressure can be set to a sufficiently small value, thus making it possible to improve the traceability of the outer cutters relative to the skin with resultant better shaving feeling. At this time, the blind cover has already started to descend, so that the remaining cutter circumferential rims will be subjected to the upward force of one inner cutter which is in sliding contact with the outer cutter, thus requiring a relatively small depressing force for the remaining cutter circumferential rims to descend and tilt. With this arrangement, adjoining cutter circumferential rims will be easily depressed when a head unit is slid on the skin, and smooth movement can be achieved, leading to improved shaving feeling.
Here, each of the cutter circumferential rims has a blind cover upwardly engaged therewith, so that the cutter circumferential rim restores to its stationary position by the force of restoration to an upright position of the inner cutter drive shaft and an upward force of the blind cover. Therefore, the inclination of the outer cutter can be arbitrarily set by appropriately setting the upward force of the blind cover. For example, the upper surface of the outer cutter can be inclined outward in its stationary mode. Moreover, the inclinable range of the cutter circumferential rims can be expanded.
Furthermore, there is no need to provide the upper surface of the shaver main body (the head bottom plate) with a wall, namely, an upright wall, which surrounds the cutter circumferential rim, thus permitting a reduced size of the head unit. Further, since the upright wall is unnecessary and gaps among the cutter circumferential rims are covered by the blind cover, the chances of entry of shaving debris from thereunder are minimized and the detachable designs of the cutter circumferential rims and the blind cover permit easy removal of shaving debris.
Preferably, the outer cutters are disposed at equal intervals in a circumferential direction around the center of the shaver main body (head), as observed in a top plan view, and each of the cutter circumferential rims is held on a straight line (pivotal axis) which is orthogonal to a straight line in a radial direction passing the center of the shaver main body and the center of the outer cutter and which also passes the center of the outer cutter, as observed in a top plan view, while the blind cover is held at the center of the shaver main body (head). In this case, the upward forces applied to the plurality of outer cutters will be equal and every outer cutter will share the same condition of use, thus providing excellent shaving feeling.
Preferably, the blind cover is retained at the center of the main body such that the blind cover is movable in the vertical direction within a predetermined range and also free to move in an inclining direction, while being provided with an upward restoring tendency by a spring or the like. In this case, for example, a depressing force applied to one cutter circumferential rim causes the blind cover to descend while tilting, leading to improved traceability of the blind cover relative to the cutter circumferential rim.
Preferably, the blind cover comprises a cylindrical pillar locked by a clicking mechanism or a snapping mechanism onto a cover mounting shaft rising from the center of the head bottom plate, a coil spring is accommodated in the pillar, and a coil spring is abutted against the upper end of the cover mounting shaft thereby to impart the upward restoring force to the blind cover. By setting the coil spring to a sufficiently low tension, the depressing force (descending start pressure) or the inclination start pressure of the cutter circumferential rims can be controlled to a sufficiently small value, permitting further improved shaving feeling.
The blind cover preferably has a shape which extends out from the center of the main body in the radial direction via the gap between adjoining cutter circumferential rims. This makes it possible to minimize the size of the blind cover with a consequent reduced weight, permitting further improved traceability relative to the vertical movements of the cutter circumferential rims.
Referring to
Each of the cutter assemblies 20 is pivotable about a straight line (pivotal axis) C which is orthogonal to a straight line B in a radial direction passing a center P (
As illustrated in
The cutter assembly 20 will now be described with reference to
The cutter circumferential rim 24 is provided with another pair of guide walls 34a, 34a on the opposite side from the guide walls 34, 34, sandwiching the pivotal axis C therebetween. A semicircular descent wall 44 is formed on the outer side of the guide walls 34a, 34a to surround the guide walls 34a, 34a. Both ends of the descent wall 44 extend out to cover the outer sides of the upright walls 36, 36 (refer to
As illustrated in
As illustrated in
The cutter assembly 20 constructed as described above is detachably mounted on the head bottom plate 18 of the main body 10 by the pivotal supporting sections 22. More specifically, three inner cutter drive shafts 56 projected from the head bottom plate 18, and a pair of pillars 60 is installed in a protruding manner on the pivotal axis C of each of the three cutter assemblies 20, each of the inner cutter drive shafts 56 being held therebetween (refer to
A blind cover mounting shaft 64 projects out at the center of the head bottom plate 18 of the shaver main body 10, and a trifurcate blind cover 66 is detachably installed onto the blind cover mounting shaft 64 (
Here, the mounting section of the blind cover 66 will be described in detail. As illustrated in
The pillar 68 is joined to the mounting shaft 64, the coil spring 64c being installed between the inner bottom of the pillar 68 and the upper end portion 64a of the mounting shaft 64. More specifically, aligning the bottom end of the pillar 68 to the upper end portion 64a of the mounting shaft 64 and then pushing the bottom end of the pillar 68 downward causes the clip 68b to be pushed open once by the upper end portion 64a of the mounting shaft 64, thus engaging the clip 68b with the smaller-diameter portion 64b. As a result, the blind cover 66 is free to move (vertically movable and also inclinable) within the range of the vertical dimension of the smaller-diameter portion 64b and is provided with an upward restoring tendency by the coil spring 64c. Further, the clip 68b abuts against the bottom edge of the upper end portion 64a from the side of the smaller-diameter portion 64b, thereby restricting the upward movable range of the blind cover 66. This state is illustrated in
After attaching the cover 66 to the head bottom plate 18, the cutter assembly 20 is detachably installed onto the pillars 60 with a click. More specifically, the lower end of the inner cutter shaft 30 is aligned with the inner cutter drive shaft 56 while setting the descent wall 44 of the cutter circumferential rim 24 of the cutter assembly 20 along the outer periphery of the head bottom plate 18. An upward restoring tendency is imparted to the polygonal (rectangular) engaging head of the inner cutter drive shaft 56 by a coil spring (not shown) built in the inner cutter drive shaft 56. The lower end of the inner cutter shaft 30 has an engaging recess in which the engaging head of the drive shaft 56 is locked. With such arrangement, by pushing the cutter assembly 20 downward, the inner cutter 28 comes in an upward resilient contact with the outer cutter 16 by the restoring force of the inner cutter drive shaft 56.
When the cutter assembly 20 is further pushed downward against the restoring force, the distal projection 40a of the pivotable axial member 40 attached to the cutter circumferential rim 24 comes in contact with the upper edge of the pillar 60 of the head bottom plate 18 and to be pushed in against the wire spring 42 until the projection 40a engages with the engaging recess 62 of the pillar 60 with a snap or a click. In this state, the cutter assembly 20 pivotally moves about the pivotable axial member 40, i.e., the pivotal axis C.
The restoring force of the coil spring built in the inner cutter drive shaft 56 is applied to the outer cutter 16 and the cutter circumferential rim 24 upward through the intermediary of the inner cutter 28. The upward restoring force of the inner cutter drive shaft 56 acts on the pivotal axis C of the cutter circumferential rim 24 (
With the three cutter assemblies 20 installed, pressing the central area of the head unit 14 against the skin to be shaved causes the cutter assemblies 20 to go down at the center of the head unit 14. In other words, the central portion of the head unit 14 goes down about the pivotal axis C (the state illustrated in
On the other hand, the cutter circumferential rim 24 does not pivotally move in the direction orthogonal to the pivotal axis C, so that the contact pressure on the skin on the pivotal axis will be absorbed only by the vertical movement of the outer cutter 16 relative to the cutter circumferential rim 24, leading to a possibility of inadequate absorption of the contact pressure. However, the upper surface of the cutter circumferential rim 24 expands out over the pivotal supporting sections 22, that is, expands in the direction of the pivotal axis C; therefore, the area of contact with the skin in the direction of the pivotal axis C is increased. This leads to a lower pressure of contact (the contact pressure per unit area) between the skin and the outer cutters, thus enhancing the protective effect for skin.
The pivotal supporting sections 22 supporting the cutter circumferential rim 24 is not located between the cutter circumferential rim 24 and the head bottom plate 18, which provides the outer cutter frame. Rather, the pivotal supporting section 21 is located under the cutter circumferential rim. This arrangement makes it possible to reduce the size of the head bottom plate 18 and minimize the chances of shaving debris adhering to the pivotal supporting sections 22. Furthermore, each of the cutter assemblies 20 is detachably installed to the main body 10, permitting easy cleaning of the head unit 14.
The cutter circumferential rims 24 of the three cutter assemblies 20 are in the state illustrated in
In addition, since the blind cover 66 pushes up the cutter circumferential rims 24, the angles of the upper surfaces of the outer cutters 16 in the stationary (normal standby) mode can be set such that the outer cutters 16 are inclined outward, as illustrated in
Number | Date | Country | Kind |
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2008-168806 | Jun 2008 | JP | national |