Cosmetic Applicator

Abstract

A cosmetic applicator with which eyelashes can be easily increased in apparent fullness and/or curled may include an applying portion consisting of a linear core wire portion comprising at least two metal core wires helically twisted together, and a multiplicity of bristles pinched by a twisted portion of the core wires and continuing in helicoidal fashion in an axial direction of the core wire portion while being distributed in radial fashion thereabout. The applying portion may have a three-dimensional external shape which is a locus formed by causing a shape that is substantially polygonal with interior angles that are each not greater than 180° as seen in sectional view at any position along an axial direction of the core wire portion to be rotated in continuous fashion in a circumferential direction about the axis of the core wire portion as it is made to advance in the axis direction of the core wire portion.

What is claimed is: 
     
         1 . A cosmetic applicator comprising
 an applying portion having
 a linear core wire portion formed of at least two metal core wires helically twisted together; and 
 a multiplicity of bristles pinched by a twisted portion of the core wires and continuing in helicoidal fashion in an axial direction of the core wire portion while being distributed in radial fashion thereabout; 
   wherein the applying portion has a three-dimensional external shape which is a locus formed by causing a third shape that is substantially polygonal with interior angles that are each not greater than 180° as seen in sectional view at any position along the axial direction of the core wire portion to be rotated in continuous fashion in a circumferential direction about an axis of the core wire portion as it is made to advance in the axial direction of the core wire portion;   the third shape is a bilaterally symmetrical shape formed by superposing a first shape and a second shape, the first shape being a bilaterally symmetrical polygonal shape, an uppermost side of the first shape being the longest side of the first shape, the second shape being an isosceles triangle, the bottommost side of the second shape being the uppermost side of the first shape, the bottommost side of the second shape being straddled in isogonal fashion by two sides of the second shape that are each longer than any of the sides making up the first shape except for the uppermost side of the first shape; and   the core wire portion is eccentrically located, being disposed in the direction of the first shape, from a midpoint along a line of bilateral symmetry of the third shape.   
     
     
         2 . The cosmetic applicator according to  claim 1  wherein
 the third shape is a bilaterally symmetrical substantially pentagonal shape; 
 the first shape is an isosceles trapezoid obtained by bisecting a regular hexagon at two vertices thereof; and 
 the second shape is an isosceles triangle, the bottommost side of which is the longest side of the first shape, the second shape having two sides that are each longer than any one side of the regular hexagon. 
 
     
     
         3 . The cosmetic applicator according to  claim 1  wherein
 the third shape is a substantially hexagonal shape; 
 the first shape is a bilaterally symmetrical trapezoid; and 
 the second shape is a substantially quadrilateral shape in which what would otherwise be an angle formed by the two sides of the second shape that are each longer than any of the sides making up the first shape except for the uppermost side of the first shape is instead made to be an arc centered on the core wire portion. 
 
     
     
         4 . A manufacturing method of the cosmetic applicator according to  claim 1  comprising:
 a preparation step of forming a cosmetic brush precursor that includes an applying portion consisting of a linear core wire portion formed of at least two core wires and bristles distributed in radial fashion from a twisted portion of the core wires that continues in helicoidal fashion and is formed by causing a multiplicity of bristles with prescribed lengths that are arranged in parallel band-like fashion to be pinched between the at least two core wires and twisted thereabout in helical fashion; 
 a trimming step of forming an external shape of the applying portion into a substantially columnar shape by uniformly cutting tip ends of the bristles constituting the applying portion; 
 a position adjusting step of adjusting a positional relationship between the cosmetic brush precursor and a machining device including a cutting blade and a receiving blade which are of prescribed width and are flat blades to shear the bristles constituting the applying portion; and 
 a main machining step of forming a shear surface extending in helicoidal fashion on the external shape of the applying portion by shearing tip ends of the bristles of the applying portion by relatively moving the machining device parallel to the axial direction of the core wire portion while rotating the cosmetic brush precursor around the core wire portion. 
 
     
     
         5 . The manufacturing method of the cosmetic applicator according to  claim 4  wherein
 in the main machining step, the cosmetic brush precursor is rotated a prescribed angle about the core wire portion, and 
 by carrying out the position adjusting step and the main machining step in iterative fashion a prescribed number of times, an applying portion with a desired shape is formed. 
 
     
     
         6 . The manufacturing method of the cosmetic applicator according to  claim 5  wherein
 the prescribed number of times is equal to the number of straight sides constituting the third shape.