Patent ID: 8109481

Claim:
An operation device comprising: a main body; an operation panel body attached to the main body rotatably around a rotation axis, such that a rotation of the operation panel body allows a posture of the operation panel body to change to take a first posture falling with respect to the main body and a second posture rising with respect to the main body, and a tilt mechanism configured to maintain the operation panel body at predetermined rotation angles, wherein the tilt mechanism comprises: a plurality of substantially V-shaped recessed grooves formed at one of the operation panel body and the main body, the recessed grooves recessed in a radial direction of the rotation axis of the operation panel body and arranged along a circumferential direction of the rotation axis; a substantially V-shaped pawl member provided at the other of the operation panel body and the main body, the pawl member configured to engage with and disengage from the recessed groove at a predetermined position of the circumferential direction of the rotation axis; and an urging member provided at the other of the operation panel body and the main body, the urging member configured to elastically urge the pawl member in a direction that the pawl member engages with the recessed groove, wherein, when the pawl member is urged by the urging member and engages with the recessed groove, the pawl member contacts with the recessed groove at a first position and a second position, the first position at which a contact pressure in the recessed groove increases in case where the operation panel body rotates toward the first posture side, and the second position at which a contact pressure in the recessed groove increases in case where the operation panel body rotates toward the second posture side, and wherein a following relationship is satisfied: 0°<θ1<θ2<90° where, in cross-section orthogonal to the rotation axis, an angle θ 1 is defined between: a first imaginary line connecting the first position and the rotation axis; and a second imaginary line along an inclined surface of the first position side in the recessed groove, and an angle θ 2 is defined between: a third imaginary line connecting the second position and the rotation axis; and a fourth imaginary line along an inclined surface of the second position side in the recessed groove.