Cutlery – Blades – Razor blade
Reexamination Certificate
1998-09-21
2002-03-12
Payer, Hwei-Siu (Department: 3724)
Cutlery
Blades
Razor blade
C030S346510
Reexamination Certificate
active
06354008
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to sliding members having a sliding surface for sliding contact with a cooperative member, such as inner and outer blades of an electric shaver, compressor parts, VTR parts and thin film magnetic heads. The present invention further relates to a method of forming a film on a substrate by utilizing a CVD method.
2. Description of Related Art
Investigations have been made as to the formation of a protective film, such as a nitride or diamond-like carbon film, on a skin-contacting, outer surface of an outer blade of an electric shaver, which can impart improved wear-resistance thereto. However, the formation of protective film on an inner surface of the outer blade, which is brought into contact with an inner blade of the electric shaver, has not been put into general practice up to date. Likewise, the formation of protective film on an sliding surface of a distal edge of the inner blade of electric shaver, which is brought into contact with the outer blade, has not been put into general practice up to date.
The inventors of the present application have investigated to what extent wear-resistance can be improved by providing a protective film, such as a diamond-like carbon film, on a sliding surface of an inner or outer blade of an electric shaver, and found that such formation of protective film on the sliding surface results in delamination thereof from the sliding surface or in cutout thereof at the edges of sliding surface, which causes wear of the sliding surface.
Such occurrence of delamination or cutout of the protective film is not limited to the cases where it is applied to the inner or outer blade of an electric shaver, and can also be found in the cases where it is applied onto sliding surfaces, such as of sliding parts of compressor, sliding members of VTR and thin film magnetic heads.
For these sliding members, a protective film is sought which exhibits reduced amount of wear and excellent sliding characteristics.
A plasma CVD method, which deposits a film by decomposing a source gas in a plasma, has been widely used as a measure of forming a film at a relatively low temperature, and is capable of forming films having various compositions by suitably selecting the source gas. Such a CVD method can be utilized to form various films, such as diamond-like carbon films having high degrees of hardness, carbon nitride (CN) and carbon silicide (CSi) films respectively having low levels of friction coefficient.
For example, a diamond-like carbon film, when formed on a silicon substrate, shows a good adhesion to the silicon substrate. However, when attempted to form a carbon nitride or carbon silicide film on the silicon substrate by using conventional film-forming techniques, there arises a problem of poor adhesion therebetween.
SUMMARY OF THE INVENTION
A first object of the present invention is to prevent delamination or cutout of a protective film provided on a sliding surface of a sliding member.
A second object of the present invention is to provide a sliding member carrying on its sliding surface a protective film which exhibits a reduced level of wear and is excellent in sliding characteristics.
A third object of the present invention is to provide a method of forming a film which is as highly functional as a carbon nitride or carbon silicide film and which exhibits good adhesion to a substrate by utilizing a plasma CVD method.
A sliding member in accordance with a first aspect of the present invention is the sliding member having a sliding surface for sliding contact with a cooperative member. A protective film is deposited over the sliding surface and a surface region immediately adjacent the sliding surface in such a characteristic manner that a ratio d
1
/d
2
is controlled to be less than 1, wherein d
1
is a thickness of the protective film overlying the sliding surface and d
2
is a thickness of the protective film overlying the surface region immediately adjacent the sliding surface.
In a first preferred embodiment according to the first aspect of the present invention, the sliding member is an inner blade of an electric shaver. That is, the electric shaver inner blade of this embodiment has at its distal end a sliding surface for sliding contact with an outer blade of the electric shaver. A protective film is deposited not only on the sliding surface but also on side regions of the inner blade immediately adjacent the sliding surface, in such a characteristic manner that a ratio d
1
/d
2
is controlled to be not less than 1, wherein d
1
is a thickness of the protective film overlying the sliding surface and d
2
is a thickness of the protective film overlying the side regions.
In a second preferred embodiment according to the first aspect of the present invention, the sliding member is an outer blade of an electric shaver. That is, the electric shaver outer blade of this embodiment defines a sliding surface, which is brought into sliding contact with an electric shaver inner blade, on its inner surface region around a hole for catching the beard. The outer blade carries the protective film not only on its sliding surface but also on an outer surface region around the hole in such a characteristic manner that a ratio d
1
/d
2
is controlled to be not less than 1, wherein d
1
is a thickness of the protective film overlying the sliding surface and d
2
is a thickness of the protective film overlying the outer surface region.
In the first aspect of the present invention, the region immediately adjacent the sliding surface refers to the region which extends from an edge of the sliding surface at least a distance corresponding in dimension to the thickness of the protective film overlying the sliding surface.
In the first aspect of the present invention, the aforementioned thickness ratio d
1
/d
2
is not less than 1, as specified above, preferably in the range of 1.05~5.0, more preferably in the range of 1.1~3.3.
The deposition of the protective film not only on the sliding surface but also on the region immediately adjacent the sliding surface, in accordance with the first aspect of the present invention, effectively prevents the occurrence of delamination or cutout of the protective film. If the thickness d
2
of protective film, either deposited on the side regions immediately adjacent the sliding surface of the electric shaver inner blade, or deposited on the outer surface region of the electric shaver outer blade around the hole for catching the beard, is controlled to fall within the above-specified range, the delamination or cutout of the protective film on the sliding surface of either member can be prevented, while either member can maintain its function as a sliding member.
In the first aspect of the present invention, the thickness ratio d
1
/d
2
of the protective films is controlled to fall within the range as specified above. The thickness d
1
of protective film on the sliding surface is suitably selected depending on the particular uses of sliding members, but is generally preferred to fall within the approximate range of 50 Å~10 &mgr;m.
In the first aspect of the present invention, the hardness of protective film is preferably not less than 1000 Hv, more preferably not less than 1500 Hv.
A sliding member in accordance with the second aspect of the present invention is the sliding member having a sliding surface for sliding contact with a cooperative member. The sliding member carries a protective film at least on its sliding surface. Characteristically, the protective film is varied in thickness to have projected and depressed portions which together define an irregular surface profile.
In the second aspect of the present invention, the projected and depressed portions of the protective film may be arranged in either regular or irregular pattern. For example, the projected and depressed portions of the protective film may be alternatingly arranged to provide a striped pattern on the surface of the protective film.
In the second aspect of the present inventi
Domoto Yoichi
Hirano Hitoshi
Kuramoto Keiichi
Arent Fox Kintner & Plotkin & Kahn, PLLC
Payer Hwei-Siu
Sanyo Electric Co., Inc.
LandOfFree
Sliding member, inner and outer blades of an electric shaver... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Sliding member, inner and outer blades of an electric shaver..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sliding member, inner and outer blades of an electric shaver... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2844419