Safety razors
AssigneeThe Gillette Company
InventorKevin J. Wain
Life of this patent
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AssigneeThe Gillette Company
InventorKevin J. Wain
Estimating the term…
A safety razor blade unit (2) has blade assembly (5) comprising a plurality of parallel blades (16) mounted on a razor handle (1) by a flexible support structure (4). Each blade (16) consists of an elongate blade element having a forward edge section (50) with a sharp cutting edge (17), and a planar blade section (54) extending rearwardly from the forward edge section (50). The forward edge section is upwardly inclined by bending a blade element blank between press tooling so that in the transition region between the forward edge section (50), which extends back from the tip of the cutting edge (17) by not more than 1 mm, and the planar blade section (54), the lower surface is convex and the upper surface is concave, with the plane (Pt) bisecting the tip being at an angle of 10° to 35° to the mid plane (Pm) of the planar section (54). The blade 16 is positioned in the blade unit (2) with the mid plane (Pm) of the planar section parallel to a tangent plane tangential to surfaces of the guard (26) and the cap (24) of the blade unit. The tip of the cutting edge is at a height of 0.05 to 0.15 mm above the plane (Pn) of the upper surface at the planar section, and to ensure good flexibility the blade cross section has a minimum second moment of inertia not greater than 1.0×10−4 mm4.
A blade for a safety razor blade unit, comprising an elongate blade element with upper and lower surfaces, a forward edge section having a sharp cutting edge extending therealong and defined by surface portions which taper towards the tip of the cutting edge, and a substantially planar blade section extending rearwardly from the forward edge section and over which the upper and lower surfaces are parallel, wherein in a transition region between the planar blade section and the forward edge section the lower surface has a convex curvature and the upper surface is non-convex, and characterized in that along at least most of the length of the blade, the blade cross element section has a minimum second moment of area not greater than 1.0×10−4 mm4.
Dependencies are inferred from the claim text.