Cutlery – Razors
Reexamination Certificate
1999-07-02
2001-01-23
Rachuba, M. (Department: 3724)
Cutlery
Razors
C030S049000, C030S050000, C030S346550, C030S346560, C030S346570
Reexamination Certificate
active
06176014
ABSTRACT:
This invention relates to safety razors, that is razors with cutting elements having sharpened edges which cut through the hairs due to the movement of the cutting element across the skin during shaving, and without the cutting element and another member being driven relative to each other to produce a shearing action. The invention is particularly concerned with a novel form of cutting element for a safety razor blade unit, and with a blade unit incorporating such a cutting element.
Safety razors generally comprise a blade unit with one or more cutting elements which are moved across the skin during shaving by means of a handle to which the blade unit is attached. A blade unit can be fixedly mounted on a handle with the intention that the entire razor be discarded when the cutting edges have become dulled, or the cutting element(s) can be replaceable in the blade unit. Alternatively, a blade unit can be detachably mounted on a handle for replacement when required. Replaceable blade units are commonly referred to as cartridges.
Most safety razors in current use have cutting members in the form of blades with rectilinear sharpened edges extending perpendicular to the direction in which the blades are intended to be moved over the skin in use. There is a tendency for a hair to be knocked over by a blade edge before the blade cuts through the hair, but effective cutting of the hair is obtained nonetheless as a result of the hair root being held firmly by the skin and the blade edge being located. closely adjacent the skin surface. It has been suggested to incline the blade edge to the direction of movement over the skin in order to produce more of a slicing cutting action, but such proposals have not gained acceptance due to increased risk of injury due to the blade cutting the skin.
The present invention resides in a new form of cutting element which represents a significant departure from the prior art practices. According to the invention there is provided a cutting element for a safety razor comprising slots tapering from open forward ends to substantially closed trailing ends, each slot being confined between a pair of edges at least one of which is sharpened for slicing hairs entering the slot and moving therealong towards the trailing end as the cutting element is moved across the skin during shaving.
With a cutting element according to the invention the sharpened edges can extend substantially in alignment with the direction of movement of the cutting element across the skin so that hairs are effectively sliced through, but the slots can be narrow enough to prevent skin from entering the slots so the risk of cutting the skin is no worse than with conventional razor blades, and it can even be reduced. A further benefit of the cutting element of the invention is that the sharpened edges need not scrape the skin surface in the same manner as conventional razor blades, and as a consequence less skin tissue will be removed during shaving. Furthermore, due to the hairs being cut through with a slicing action there may be an improved post-shave comfort as the cut end faces of the hairs will be more perpendicular to the length of the hairs and parallel to the skin than in the case of hairs cut with conventional blades which tend to knock the hairs over and cut them along planes at a shallow angle to the hair lengths thereby leaving pointed ends to the cut hairs.
In the preferred embodiments of a cutting element according to the invention, both edges of each slot are sharpened for enhanced hair slicing efficiency. The angle of taper, i.e. the angle between the opposed edges of a slot is suitably not greater than 10° and an angle of taper in the range of 3° to 7° is appropriate. The length of the cutting edges measured along the slots need not be great and effective slicing of hairs can be achieved with a length in the range of 1 to 2.5 mm. The width of the slots at the forward end of the sharpened edges is in the range of 50 to 500 &mgr;m.
Most conveniently the cutting element is elongated with a series of parallel slots distributed along the element to extend substantially perpendicular to the length of the element, the slots being preferably positioned at a pitch in the range of 0.5 to 2.0 mm.
The invention includes within its ambit a safety razor equipped with a cutting element in accordance with the invention, and a safety razor blade unit with a cutting element according to the invention. Two or more such cutting elements would be included in a blade unit to be moved over the skin in turn, the slots of all the cutting elements being directed in the same forward direction.
In addition a cutting element according to the invention could be utilised in a blade unit in combination with a conventional blade having a rectilinear sharpened edge, and the cutting element could be located in front of or behind the edge of the conventional blade with its slots substantially perpendicular to the length of the blade edge.
Another embodiment of a blade unit includes two cutting elements according to the invention arranged back-to-back to enable the blade unit to shave in two directions. Furthermore, several cutting elements could be utilised in a pad type razor with their slots oriented in different directions so that hairs will be shaved when the razor head including the cutting elements is rubbed over the skin surface moving in various directions.
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Boukus, Jr. Charles P.
Rachuba M.
The Gillette Company
Tobin Donal B.
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