Cutlery – Razors – Combined
Reexamination Certificate
1998-11-20
2001-05-22
Huson, Gregory L. (Department: 3729)
Cutlery
Razors
Combined
C030S034050, C030S050000
Reexamination Certificate
active
06233829
ABSTRACT:
This invention relates to safety razors and in particular the invention is concerned with a blade unit having one or more elongate blades and a skin engaging member for engaging the skin in advance of a blade 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 on the handle to enable the blade unit to be replaced by a fresh blade unit when required. Replacement blade units are also commonly referred to as cartridges. Alternatively, a blade unit may be attached permanently to the handle with the intention that the entire razor should be discarded when the blade or blades have become dulled.
In general a blade unit has a guard for contacting the skin in advance of the blade edge(s) as the blades are moved across the skin during shaving, and a cap for contacting the skin behind the blade edge(s). Many different surface configurations and materials have been proposed for the guard surface. Thus guards have been designed to stretch the skin ahead of the blade, or to impart pleasant tactile sensations to the skin as the guard slides across its surface.
In our U.S. patent application Ser. No. WO 95/29043 there is described a blade unit having a skin engaging member for engaging the skin in advance of a blade edge, this member having a series of elements defining slots through which the hairs pass, and the elements being arranged to engage frictionally the hairs passing along the slots in order to apply a light pulling force on the hairs. The pulling force can increase the extension of the hairs from the skin before they are cut by the blade, without causing any noticeable discomfort.
The present invention is directed to an improved blade unit of the foregoing form and in accordance with the invention there is provided a blade unit comprising at least one blade with an elongate edge, a skin engagement surface for engaging the skin ahead of the blade edge during shaving, the skin engaging surface having slots for hairs to pass through, wherein the slot edges are formed to notch the hairs as they pass through the slots, and in the direction towards the blade, the slot edge formations are inclined for guiding the notched hairs to follow a path causing the extension of the hairs from the skin to be increased before the hairs are cut by the blade edge.
A blade unit according to the invention is adapted to exert a more positive pulling force for extending the hairs than is obtained by the previously proposed skin engaging member which relies solely on the friction between the sides of the slots and the hairs to resist the movement of the hairs with the skin as the skin slides over the skin engaging surface. With the present invention the hairs become notched and the edges of the slots can perform like rails to guide the hairs so that they are moved away from the skin and hence become pulled to increase their projecting length. Somewhat surprisingly this pulling effect, which enhances the closeness of the shave obtained by use of the blade unit, does not seriously impair the comfort level experienced during use of the blade unit.
In the presently preferred construction embodying the invention the skin engagement surface is defined by a series of elements between which the slots are formed, the elements having trailing end parts which extend from those parts thereof which define the surface and which are inclined downwardly, i.e. away from the skin in use of the blade unit. The slots taper in width across the skin engagement surface, but are of substantially constant width between the trailing end parts. For notching and subsequently guiding the hairs the elements have edge portions of reduced thickness conveniently provided by etching the undersides of the elements to form rebates. An appropriate edge thickness is around 20 microns or less. The reduced thickness edges of the trailing parts of the elements are inclined downwardly from the skin engagement surface at an angle of 30° to 70°, preferably between 40° and 60°.
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Oglesby Oliver David
Wain Kevin James
Boukus, Jr. Charles P.
Huson Gregory L.
The Gillette Company
Tobin Donal B.
Tugbang A. Dexter
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