Cutlery – Razors – With cooperating shearing blades
Reexamination Certificate
2001-07-19
2003-05-27
Payer, Hwei-Siu (Department: 3724)
Cutlery
Razors
With cooperating shearing blades
C030S043100, C030S043600, C030S043920
Reexamination Certificate
active
06568083
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a dry shaver with a height adjustable cutter head, and more particularly to the shaver having a floating cutter head which is capable of being depressed equally at different positions but against differing biasing forces.
BACKGROUND ART
A shaver with a floating cutter head is known in the art, for example, in U.S. Pat. No. 5,398,412 to be advantageous for making it easy to move the cutter head in smooth contact with various portions of a user's face for effective shaving. The cutter head comprises a head frame which carries an outer cutter and is mounted on top of a shaver housing. An inner cutter is urged by a bias spring into pressed contact with the outer cutter and is driven to move relative to the outer cutter for shearing the hairs. The head frame is floatingly supported to the shaver housing so that the cutter head can be depressed while compressing the bias spring. Thus, the biasing force of the spring increases as the cutter head is depressed. When the user intends to shave the hard hairs, the cutter head is depressed deeply to increase the biasing force, i.e., the contact pressure between the outer cutter and the inner cutter for successfully shearing the hard hairs with the increased contact pressure. The deeper the cutter head is depressed to increase the contact pressure, the more the skin experiences a counter-pressure from the outer cutter. The counter-pressure is inevitable for the shaving, but should be kept within a tolerable range since too-much counter-pressure can irritate the skin. However, when shaving the hard hairs with the floatingly supported cutter head of the above patent, the cutter head has to be depressed deeply with an attendant increase in the counter-pressure. In other words, the shaving of the hard hairs is made only after the cutter head is depressed deeply at the sacrifice of the increased counter-pressure, while the shaving of the soft hairs can be made even without depressing the cutter head and therefore only at a slight counter-pressure to the skin. Consequently, in order to reduce the skin irritation, it is highly desirable that the cutter head gives a reduced counter-pressure to the skin even for shaving the hard hairs with the increased contact pressure between the outer and inner cutters.
In the meanwhile, Japanese Patent Early Publication (KOKAI) No. 60-176679 discloses one solution of adjusting the contact pressure between the outer cutter and the inner cutter. The outer cutter is fixedly mounted on top of a shaver housing, while the inner cutter is urged by a bias spring against the outer cutter. The bias spring is supported to a drive element for the inner cutter and is compressed between the inner cutter and the drive element for giving a suitable contact pressure between the outer cutter and the inner cutter. The contact pressure is adjusted by varying a compression amount of the bias spring with the outer cutter being kept in a fixed position. Since the outer cutter is not capable of being depressed in a direction of varying the compression amount of the bias spring, the contact pressure has to be adjusted by use of an actuator which is connected to the bias spring or to the drive element for directly deforming the bias spring or moving the drive element of the inner cutter towards and away from the outer cutter. The actuator moves together with the drive element, i.e., the inner cutter and therefore gives rise to a considerable friction with a handle mounted on the shaver housing for manipulation of the actuator, thereby inevitably developing an additional friction at the interconnection between the moving actuator and the handle, which should be avoided for reducing noise and power consumption.
DISCLOSURE OF THE INVENTION
The present invention has been accomplished in view of the above insufficiency to provide an improved dry shaver which is capable of being depressed equally at different positions but with differing contact pressures between the outer and inner cutters. The shaver in accordance with the present invention comprises a housing having a motor and mounting the outer cutter and the inner cutter at its upper end. The inner cutter is driven by the motor to move in shearing engagement with the outer cutter for shaving the hairs. The inner cutter is urged upwardly by a bias spring to develop a contact pressure at which the inner cutter is pressed against the outer cutter. The outer cutter is carried by a cutter holder which is movably supported to a head frame mounted on top of the housing. Included in the shaver is a height adjust mechanism for adjusting the height of the head frame relative to the housing between a high position and a low position while compressing the bias spring differently to vary the contact pressure, and for allowing the cutter holder to be depressed relative to the head frame at each of the high and low positions. Therefore, in addition to that the outer cutter can be depressed further even at the low position when shaving the hard hairs, the hard hair shaving can be initiated at the low position where the increased contact pressure is available but with the outer cutter being held undepressed relative to the head frame, and therefore without exerting the increased counter-pressure to the skin, thereby enabling to shave the hard hairs successfully with the increased contact pressure but without irritating the skin. Stating differently, the increased contact pressure effective for shaving the hard hairs can be initially set without depressing the outer cutter which would otherwise increase the counter-pressure on the skin. Shaving of soft hairs can be made with the head frame held at the high position where the outer cutter is allowed to follow the contour of the skin only accompanied with less counter-pressure on the skin and where the contact pressure is low but sufficient for shaving the soft hairs.
Accordingly, it is a primary object of the present invention to provide an improved dry shaver which is capable of shaving the hard hairs successfully and easily in a like manner as shaving the soft hairs.
Preferably, the head frame has a head cover projecting on top of the housing to surround the outer cutter in such a way that the outer cutter exposed on the head cover. The height adjust mechanism is interlocked with the head cover so as to move he head cover together with the head frame between the high and low positions. Thus, the outer cutter is kept exposed on the head cover equally irrespective of the high and low position that the head frame takes, assuring convenient shaving of the hairs while varying the contact pressure.
The inner cutter is driven to move by a drive element projecting on top of the housing. It is this drive element that mounts the bias spring with one end of the spring retained to the drive element and with the other end of the spring being held in pressed contact against the inner cutter, developing the contact pressure between the outer and inner cutters. Thus, as the outer cutter, i.e., the head frame is depressed deeper, the contact pressure will increase for facilitating the shaving of the hard hairs.
In a preferred embodiment, the height adjust mechanism comprises a handle and a slider which is actuated by the handle to vertically move the head frame. The slider has an upper end projecting on top of the housing for detachable engagement with the head frame, enabling the head frame to be removed from the housing for cleaning of the shaver.
The housing is formed on its top wall with a fixed mount frame for detachably mounting the head frame. The mount frame has a peripheral wall projecting on top of the housing in an overlapping relation with the head frame along the entire periphery of the housing irrespective of the position of the head frame relative to the housing. With this arrangement, it is readily possible to retain the sheared hairs within the confines of the top periphery of the housing and prevent undesired scattering of the hairs outwardly through the interface between the head frame and the hous
Ibuki Yasuo
Iwasaki Jyuzaemon
Kadowaki Mitsuhiro
Kato Hirokazu
Shiba Takeshi
Matsushita Electric & Works Ltd.
Payer Hwei-Siu
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