US Patent 10478825 Portable electric and hand operated herb grinder

A portable grinder for herb or vegetative material comprises a top section having a motor and disc with a plurality of top grinding knives protruding downward, a middle section having a plurality of bottom grinding knives protruding upward and a plurality of apertures, and a bottom section. In one embodiment, ground material is discharged through apertures in the middle section, where the size is regulated by a screen, and/or is retained in the middle section until the top section is removed. In a further embodiment, the grinder may be operated electrically or manually.