Inner rotary cutters for electric shavers and manufacturing processes for the same

A cup-shaped inner rotary cutter for an electric shaver, said cutter being adapted for a given direction of rotation and comprising:

• a circular rotary disk;
• a cylindrical section extending from the peripheral portion of said circular rotary disk in an axial direction;
• a rim section on said cylindrical section and extending substantially radially;
• and
• a plurality of U-shaped grooves extending axially through said rim section and into said cylindrical section to define a plurality of blades;
• said blades having first sections projecting in the axial direction at predetermined intervals, and second radially extending sections formed in said rim sections and having front edges in the direction of rotation of the cutter,
• said grooves extending in a direction that inclines, in the axially outward direction, in said direction of rotation of said cutters, said grooves having widths, in the circumferential direction, that do not decrease in the axial outward direction, whereby accumulation of material in said grooves during shaving is minimized.