Patent ID: 7836833

Claim:
A lock device for use in a piece of furniture, the piece of furniture comprising a rotating portion and at least one leg portion that rotatably supports the rotating portion between a substantially horizontal in-use position and a substantially vertical storage position for preventing rotation of the rotating portion of the piece of furniture, the lock device comprising: a positioning device that is configured to be provided to the at least one leg portion to abut the rotating portion when the rotating portion is in one of the in-use position and the storage position thereby to position the rotating portion in one of the in-use position and the storage position; an engaged portion that is configured to be provided to one of, the at least one leg portion, and the rotating portion; an engaging portion that is configured to be provided to the remaining one of, the at least one leg portion, and the rotating portion, where the engaged portion is not provided, the engaging portion being rotatable around an axis parallel to a rotating axis of the rotating portion, and being engageable with the engaged portion when the rotating portion is in a position positioned by the positioning device; a biasing element that biases the engaging portion in a direction of abutting the engaged portion thereby to engage the engaging portion and the engaged portion; and an operation lever that rotates the engaging portion against a biasing force of the biasing element thereby to release an engagement between the engaging portion and the engaged portion, wherein the engaging portion includes at least one engaging surface engageable with the engaged portion, wherein the engaged portion includes at last one engaged surface engageable with the engaging portion, wherein the at least one engaging surface is configured such that a moving path thereof does not cross the engaged surface, and is rotated from an engagement position in which the engaging surface contacts and engages the engaged surface in such a state where the moving path of the engaging surface does not cross the engaged surface, while being moved in a direction of departing from the engaged surface in accordance with a rotation of the engaging portion by the operation lever, wherein the at least one engaging surface of the engaging portion has a circular arc-shaped configuration, and wherein the engaging surface is configured to be rotated around a rotating axis of the engaging portion, the rotating axis being off a center of a circle that configures an arc of the engaging surface in accordance with the rotation of the engaging portion by the operation lever, and is rotated while being moved in the direction of departing from the engaged surface in accordance with a rotation of the engaging portion by the operation lever.