Resilient hinge with coil spring on pintle

A hinge device provided with:

• a fixed member for fixing said hinge device to a fixed body, said fixed member having an apertured plate body;
• a core bar which supports a rotation member and which is rotatably inserted into said aperture having a deformed non-circular area provided in said plate body and having a wall portion so as to have a suitable degree of rotative freedom to vary the rotation moment of said rotation member in accordance with an angle of rotation;
• a flat wire torsion spring having a substantially spiral shape and fixed at the inner end thereof to said core bar and the outer end thereof to said rotation member, respectively;
• a lever member fixed to one end of said core bar;
• a first flat spring fixed to said fixed member and in abutting relationship to said lever member to bias said core bar in a rotational direction through said lever member, thereby rotationally urging said core bar toward said wall of said aperture in said plate body;
• a second flat spring fixed at one end to said fixed member and having its other end extending therefrom in abutting relationship to said rotation member at the point where the rotational moment thereof is minimum and operating to counteract the spring force of said flat wire torsion spring;
• the torque of said flat wire torsion spring having a spring force more than that of said first flat spring and adapted to revolve said core bar in a direction opposite to the rotational direction of said first flat spring acting on said lever member and within a range of motion up to the maximum rotation moment, and the difference between the combined spring characteristic of said first and second flat springs, said flat wire torsion spring, and said rotation member, is such as to be within a range wherein said difference can be absorbed by the rotative friction of said rotation member.