Cutlery – Razors – Combined
Reexamination Certificate
1998-08-27
2001-10-09
Peterson, Kenneth E. (Department: 3724)
Cutlery
Razors
Combined
C030S081000
Reexamination Certificate
active
06298557
ABSTRACT:
This invention relates to shaving devices and concerns a safety razor blade unit having at least one blade with a cutting edge which is moved across the surface of the skin being shaved by means of a handle to which the blade unit is attached. The blade unit may be mounted detachably on the handle to enable the blade unit to be replaced by a fresh blade unit when the blade sharpness has diminished to an unsatisfactory level, or it may be attached permanently to the handle with the intention that the entire razor be discarded when the blade or blades have become dulled. Razor blade units generally include a guard which defines a surface for contacting the skin in front of the blade(s) and a cap for contacting the skin behind the blade(s), the cap and guard serving important roles in establishing the so-called “shaving geometry”, i.e. the parameters which determine the blade orientation and position relative to the skin during shaving. The present invention is especially concerned with the guard and/or cap of a razor blade unit.
It is known to provide a skin engaging guard or cap with surface configurations intended to produce pleasant tactile sensations during shaving, for example, as described in U.S. Pat. No. 5,191,712.
The present invention aims to provide an improved surface structure on a cap or guard and in accordance with this object the invention resides in a safety razor blade unit having at least one elongate blade and a skin engaging member defining a surface for contact with the skin during shaving, said surface being defined by spaced projections extending upwardly from a base and formed of a resiliently flexible material whereby the upper ends of the projections can deflect under forces encountered during shaving, at least some of the projections having cross-sections with concave sides so oriented that the recess formed by the concave side is open towards the direction in which the blade is moved across the skin during shaving, over at least a major part of the width of the recess.
Conveniently, the concave faces of the projections face the direction in which the blade unit is moved across the skin surface although they can be inclined to this direction at an angle of up to around 45°.
Various cross-sectional shapes for the projections are possible, but a concavo-convex shape, in particular a circular arc with a circumferential extent from ¼ to ¾ of a complete circle, preferable a semicircular arc, is expedient. An alternative cross-sectional form has an arcuate medial portion extended by straight portions, such as in the shape of a letter U.
Conveniently, the projections are arranged in one or more rows e.g., 3 or 4 rows, extending along the base generally parallel to the blade, with at least ten projections in each row, and possibly up to about 40 projections in each row for a blade unit of usual length, such as on a base around 30 mm in length. Suitably, the height of the projections above the base is in the range of 0.38 mm to 1.5 mm, preferably about 0.75 mm, the thickness (measured between the concave and convex faces) is in the range of 0.10 mm to 0.50 mm, preferable about 0.17 mm, and the base thickness (the thickness where the projections join the base) to height ratio of the projections is in the range of from 1:1 to 1:15, preferably about 1:4.4.
In the case of concavo-convex projections which in cross-sections are shaped as circular arcs or include portions of such shape, the outside diameter may be in the range of 0.3 mm to 3.0 mm, preferably around 0.75 mm, and the inside diameter may be in the range of 0.1 mm to 2.5 mm, preferably about 0.4 mm. The inside and outside diameters may increase away from the base so that the projections are flared upwardly, or they can reduce away from the base so that the projections taper towards their free ends, in either case the thickness remaining constant over the height of the projection. The thickness can also vary over the height of the projections, such as due to the internal diameter gradually increasing away from the base and/or the outside diameter gradually reducing away from the base.
The spacing between the projections in the direction perpendicular to that in which the blade unit is moved over the skin during shaving, is preferably at least 0.1 mm and not greater than the width of one projection in said direction, a most preferred spacing being around 0.25 mm. If desired, adjacent projections can be interconnected by membranes moulded integrally with the projections.
With a razor blade unit according to the invention, the skin contacting surface of the skin engaging member is highly responsive to local forces, e.g. due to a projection being encountered by a hair. The concave faces of the projections can act to funnel hairs into their recesses in order to encourage interaction with the projections. In addition these faces may serve to scoop and trap moisture from the skin and release that moisture when subsequently encountering and interacting with a hair. Furthermore, the non-linear force-deflection characteristic of the concavo-convex projections can be of advantage in their interaction with hairs.
REFERENCES:
patent: D. 175896 (1955-10-01), MacMicking
patent: D. 379675 (1997-06-01), Ichiyanagia
patent: D. 402084 (1998-12-01), Chen et al.
patent: 3722090 (1973-03-01), Dawidowicz
patent: 3797110 (1974-03-01), Michelson
patent: 4189832 (1980-02-01), Harper et al.
patent: 4247982 (1981-02-01), Booth et al.
patent: 4741103 (1988-05-01), Hultman
patent: 4912846 (1990-04-01), Yu
patent: 5092042 (1992-03-01), Miller et al.
patent: 5191712 (1993-03-01), Crook et al.
patent: 5249361 (1993-10-01), Apprille, Jr. et al.
patent: 5416973 (1995-05-01), Brown et al.
patent: 5689883 (1997-11-01), Ortiz et al.
patent: 5711076 (1998-01-01), Yin et al.
patent: 5903979 (1999-05-01), Oldroyd
patent: 5953819 (1999-09-01), Simms et al.
patent: 0397638 (1990-11-01), None
patent: 673 449 (1979-07-01), None
patent: 9635558 (1996-11-01), None
patent: 96/35558 (1996-11-01), None
Fish & Richardson P.C.
Peterson Kenneth E.
The Gillette Company
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