Patent ID: 7417695

Claim:
A mechanism for adjusting an elevation angle of an LCD, comprising: a base disposed with a lower casing at an inner surface thereof, the lower casing comprising a bottom board and two side boards respectively connecting at opposite sides of the bottom board, a slot being respectively defined in each of the two side boards near the rear ends thereof; a U-shaped locking arm disposed between the two side boards of the lower casing, the U-shaped locking arm comprising a horizontal arm and two lateral arms respectively connecting to opposite ends of the horizontal arm, each lateral arm being defined with an L-shaped hole which includes a long section and a short section extending from the long section; a pawl extending through the L-shaped holes of the U-shaped locking arm and the slots of the lower casing; a release button including a button body and a connecting rod connecting to the U-shaped locking arm, wherein when the release button is operated, the U-shaped locking arm is driven to move thereby enabling the pawl to locate at the long section or the short section of each L-shaped hole; an LCD disposed with an upper casing at the inner surface thereof, the upper casing including a support and two ratchet arcs connected to opposite sides of the support, the two ratchet arcs being respectively disposed at side surfaces of the two side boards of the lower casing, teeth being respectively disposed at the outer edges of the two ratchet arcs and including a plurality of tooth peaks and tooth valleys connecting with the tooth peaks in turn, the teeth abutting against the pawl; two rotation shafts pivotally disposed at shaft holes respectively defined in the two lateral arms of the U-shaped locking arm, the two ratchet arcs of the upper casing and the two side boards of the lower casing near the front ends thereof; and at least one return spring means controlling the pawl to constantly return to the lower end of the long section of each L-shaped hole and controlling the U-shaped locking arm to constantly return to a position enabling the short section of each L-shaped hole to locate at the pawl, wherein the return spring means normally urges the pawl to locate at one tooth valley of each ratchet arc of the upper casing and locate at the short section of each L-shaped hole of the U-shaped locking arm, whereby the upper casing and the angular relationship between the LCD and the base are restricted, and when the release button is operated, the U-shaped locking arm is driven to move such that the pawl locates at the long section of each L-shaped hole of the U-shaped locking arm to allow the tooth peaks of the upper casing to pass around the pawl, thereby rotating the upper casing and the LCD about the rotation shafts to adjust the angle of elevation of the LCD.