Hinge device

A hinge device, comprising:

• a case having a first contact portion, a second contact portion and a cylindrical portion;
• a coil spring fitted in the cylindrical portion of the case;
• a shaft member having a shaft inserted inside the coil spring, and a first engaging portion and a second engaging portion fixed to the shaft in anti-rotatable;
• wherein
• when the case is rotated relatively from a neutral position in one direction with respect to the shaft member, one end of the coil spring in contact with the first contact portion of the case is rotated relatively in the one direction with respect to the shaft member, while another end of the coil spring comes into contact with the second engaging portion of the shaft member, thereby twisting the coil spring;
• when the case is rotated relatively from the neutral position in the other direction with respect to the shaft member, the other end of the coil spring in contact with the second contact portion of the case is rotated relatively in the other direction with respect to the shaft member, while the one end of the coil spring comes into contact with the first engaging portion of the shaft member, thereby twisting the coil spring;
• and
• the first and second contact portions are formed integral with the cylindrical portion;
• wherein the one end of the coil spring is provided with a first spring holder that comes into contact with the first contact portion of the case;
• wherein the first spring holder has an arm extending in an axial direction of the shaft, and
• the cylindrical portion has an end wall provided with a groove into which the arm of the first spring holder enters.