Patent ID: 6939069

Claim:
A composite writing utensil comprising a barrel for housing a plurality of writing shafts in which a point of one writing shaft of said plurality of writing shafts can selectively be projected from a point aperture of said barrel, wherein said barrel includes a front barrel and a rear barrel which is rotatable relative to said front barrel, said composite writing utensil comprises: a cam body provided within said barrel, said cam body being unrotatable with respect to said rear barrel; and a slider unrotatable with respect to said front barrel and coupled to a rear end portion of each writing shaft, said cam body further comprises a V-shaped cam projection for projecting forward, a cam surface for facing forward and extending along the cam projection, and a restraining portion formed in an apex portion of the cam projection of said cam surface, said slider further comprises a V-shaped cam for projecting rearward, and a slidably-contacted surface for facing rearward and extending along said cam, said slidably-contacted surface being urged against said cam surface, wherein a relative rotation between said rear barrel and said front barrel causes said slidably-contacted surface of said cam to slidably-contact the cam surface and said cam to be restrained by said restraining portion, whereby a point of the writing shaft coupled to the slider provided with said cam selectively projects from the point aperture of said barrel; and an angle of inclination of said cam surface of other than a neighborhood of an apex portion of said cam projection from a line parallel to an axial direction thereof when said cam projection is developed is 1±0.5° larger than an angle of inclination of the slidably-contacted surface of said cam from a line parallel to the axial direction thereof when said cam is developed.