Patent ID: 7578031

Claim:
A hinge structure comprising: a knuckle having an inner wall surface and outer wall surface, said inner wall surface being punched outwardly to form a protrusion on said outer wall surface and an axially extending channel on said inner wall surface, thereby forming a working surface defining a working region and a locking surface defining a locking region in spatial communication with said working region; a pivot shaft extending into said knuckle, and having a peripheral locking section and a peripheral working section adjacent to said peripheral locking section; and a roller unit rotatably disposed within said locking region to contact said pivot shaft; wherein, when said peripheral locking section is aligned with said roller unit, said pivot shaft is locked to said knuckle due to biasing action of said locking surface and when said peripheral working section is aligned with said roller unit, said pivot shaft possesses a torque due to biasing action of said locking surface.