Patent Application
20070011880
In recent years shaving razors with various numbers of blades have been proposed in the patent literature and commercialized, as described, e.g., in U.S. Pat. No. 5,787,586, which generally describes a type of design that has been commercialized as the three-bladed Mach III razor by The Gillette Company, and U.S. Published Patent Application No. 2002/0144404, which describes three- and four-bladed razors.
Increasing the number of blades on a shaving razor generally tends to increase the shaving efficiency of the razor and provide better distribution of compressive forces on the skin but it can also tend to increase drag forces, reduce maneuverability, and reduce the ability to trim. Increasing the number of blades also requires increasing the area occupied by blades or reducing the spacing between the cutting edges of the blades. Increasing the area occupied by blades can affect shaving performance. Reducing the spacing between blades results in a change on the skin bulge between cutting edges and the effectiveness of the shave, potentially requiring changes in other parameters in blade geometry such as blade tangent angle and exposure. Increasing the number of blades can also affect the rinsability of the razor, which affects the ability to remove shaving debris from the blade area.
U.S. Pat. No. 5,787,586 shows razor blades that are mounted on bent metal supports, a type of support that has been reliably manufactured for years by The Gillette Company in both the Sensor and Mach III commercial products. U.S. Published Patent Application No. 2002/0144404 describes three- and four-bladed designs with straight metal support bars as blade supports and a test procedure for determining a wash through index indicating the ability of a shaving razor cartridge to be rinsed to remove shaving debris. The latter document notes that the support bars contributed to the good wash through index values reported for the described embodiments.
The invention features, in general, a cutting member for a shaving razor that includes an elongated metal blade and an elongated bent metal support that has an elongated platform portion, an elongated bent portion and an elongated base portion. In general, the blade and platform portion of the blade support are sized to make them more compact at the same time that the platform portion is provided with a sufficiently flat area for reliably supporting the blade. The platform portion extends forward from the bent portion to a front end, and includes an attachment area (e.g., a weld area) that is spaced from the front end and from the bent portion. The platform portion also includes a flat portion that includes and extends beyond the attachment area. The elongated metal blade has a cutting edge at the front, a blade end at the rear, a tapered portion leading to the cutting edge and a uniform thickness portion extending from the blade end at the rear to the tapered portion. The uniform thickness portion of the blade is supported on the platform portion and secured to the platform portion at the attachment area, and the tapered portion extends forward beyond the front end of the platform portion.
In one aspect of the invention, the blade is less than 1 mm in length from the cutting edge to the blade end, preferably less than 0.9 mm, and most preferably about 0.85 mm.
In another aspect of the invention, the platform portion of the blade support is less than 0.7 mm in length from the front end to the bent portion, preferably less than 0.6 mm, and most preferably about 0.55 mm.
In another aspect of the invention, the elongated bent metal support is made of metal that is between 0.004″ and 0.009″ thick (preferably between 0.005″ and 0.007″ and most preferably about 0.006″), and the bent portion has a radius of curvature that is less than 0.1 mm (preferably less than 0.09 mm and most preferably metal less than 0.08 mm).
In another aspect the invention features, in general, a shaving razor blade unit including at least four (preferably at least five) cutting members as already described with inter-blade spans less than 1.2 mm, preferably less than 1.1 mm, and most preferably about 1.05 mm.
Particular embodiments of the invention may include one or more of the following features. The angle between the base portion and the platform portion is between 109° and 115°, preferably between 110° and 113°, most preferably about 111.5°. The blades are secured to the platform portion by welding.
Embodiments of the invention may include one or more of the following advantages. Cutting members according to the invention can be reliably manufactured and are sufficiently compact to permit use in multi-blade razors, with at least 4 or 5 blades, while reducing spans and maintaining good rinsability.
Other advantages and features of the invention will be apparent from the following description of particular embodiments and from the claims.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
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Elongated bent metal support 400 is made of metal that is between 0.004″ and 0.009″ thick (dimension T), preferably metal between 0.005″ and 0.007″ thick, and most preferably metal about 0.006″ thick. Platform portion 406 has a length LP length from its front end 452 to the bent portion 404 less than 0.7 mm, preferably less than 0.6 mm, and most preferably about 0.55 mm. The bent portion 404 has an inner radius of curvature R that is less than 0.1 mm, preferably less than 0.09 mm and most preferably less than 0.08 mm. The angle α between base portion 402 and platform portion 406 is between 108° and 115°, preferably between 110° and 113°, most preferably about 111.5°.
Referring to
Other embodiments of the invention are within the scope of the appended claims. E.g., the blades can be attached to the bent supports by other welding techniques, e.g., arc welding, or by other attachment techniques such as adhesives or stitching.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10798525 | Mar 2004 | US |
| Child | 11524014 | Sep 2006 | US |
