Cutlery – Razors – Combined
Reexamination Certificate
2001-05-22
2003-01-07
Watts, Douglas D. (Department: 3724)
Cutlery
Razors
Combined
C030S043600, C076S104100, C076S115000
Reexamination Certificate
active
06502309
ABSTRACT:
The invention relates to a method of manufacturing a blade-shaped hair-pulling element for a cutting unit of a shaving apparatus, which cutting unit is provided with an external cutting member and an internal cutting member which can be driven with respect to the former member, said internal cutting member having cutter elements which are provided with cutting edges, while said external cutting member is provided with a wall portion with hair-trapping openings which are bounded by counter cutting edges for cooperation with the cutting edges of the drivable cutter elements, each cutting element being provided with the hair-pulling element which is in front position, as seen in the drive direction, and which is movable relative to the associated cutter element during operation of the shaving apparatus from and towards the wall portion of the external cutting member, while each hair-pulling element is provided with a thickened end with an edge which during operation of the shaving apparatus comes into contact with a hair projecting through the hair-trapping opening and pulls this hair further through the hair-trapping opening before said hair is cut off through the cooperation of the cutting edge and the counter cutting edge, said blade-shaped hair-pulling element being obtained by means of a process of shaping its outline followed by a bending process.
An example of the shaving apparatus described above is known from GB-A-2036629. During shaving, the edge of the hair-pulling element penetrates the hair somewhat, but without cutting it through. Since the hair-pulling element is movable relative to the accompanying cutter element, a pulling force will be exerted on the hair as a result of which the hair will pass farther into the hair-trapping opening, inter alia owing to the natural elasticity of the skin. This continues until the cutting edge of the cutter element hits against the hair, whereupon the cooperation between the moving cutting edge and the stationary counter cutting edge severs the hair. The hair is cut off closer to the skin as a result of this effect, and a better shaving result is obtained. The distance over which the hairs are pulled up is limited by the properties of the hairs and the skin, and in particular by the shape and dimensions of the hair-pulling elements. Thus the presence of a projecting portion of the hair-pulling element will increase the distance between the edge of the hair-pulling element and the cutting edge of the cutter element. This also increases the distance over which the hair is pulled into the hair-trapping opening, so that the hair can be cut off even closer to the skin. A hair-pulling element must be resilient, have a certain stiffness, and have a low mass if it is to function satisfactorily. After cutting of a hair, the hair-pulling element must return to its initial position as quickly as possible in order to be able to pull the next hair. Therefore, the hair-pulling element is constructed as a kind of thin blade spring. These thin, blade-shaped hair-pulling elements are obtained from a thin metal plate by means of a process of shaping the outline, and subsequently the hair-pulling elements thus obtained are given a desired shape in a bending process. A process of shaping the outline is to be understood to be, for example, a stamping process, a (laser) cutting process, or an etching process. A problem arises when a hair-pulling element is provided with a projecting portion. This projecting portion is depicted in GB-A-2036629 as a solid, integral part of the hair-pulling element, in fact in a rather theoretical manner so as to make it clear what the advantage of such a projecting portion is. It would be an obvious method to glue the projecting portion as an additional plate on the hair-pulling element. In practice, however, this is found to be unsatisfactory.
It is an object of the invention to provide the hair-pulling element of the shaving apparatus as defined in the opening paragraph with its thickened portion in a simple manner.
The invention is for this purpose characterized in that during the process of shaping the outline the blade-shaped hair-pulling element is provided with at least one tab which will subsequently lie against an end portion of the hair-pulling element as a result of a bending process, thus forming said thickened end.
Preferably, a narrow opening continuing up to said edge of the hair-pulling element is stamped out between an end portion of the hair-pulling element and the tab during the stamping process. The bending process to be performed subsequently will thus proceed with greater ease, smaller forces are required, and said edge will not be damaged at the area of the bend.
The invention also relates to a cutting unit provided with a hair-pulling element obtained by the method defined above, and to a shaving apparatus provided with said cutting unit.
REFERENCES:
patent: 4258470 (1981-03-01), Boiten et al.
patent: 4275497 (1981-06-01), Engelhardt et al.
patent: 4545120 (1985-10-01), De Vries
patent: 4630370 (1986-12-01), Hamada
patent: 2036629 (1980-07-01), None
Adriaansen Marcel
Aitink Albert Jan
De Vries Tjamme
Kadijk Simon Eme
Voorhorst Fokke Roelof
Bartlett Ernestine C.
Watts Douglas D.
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