Spring structure

A spring structure, which is mounted between a base and a moving section that advances to and retreats from the base, comprising:

• two compression coil springs including a first compression coil spring having a first winding direction and a second compression coil spring having a second winding direction, the first winding direction being different from the second winding direction;
• wherein:
• a first end portion of the first compression coil spring is supported on the base directly or through a first predetermined member, and a first end portion of the second compression coil spring is supported on the moving section directly or through a second predetermined member;
• a second end portion of the first compression coil spring is supported on a front surface of a spring seat, and a second end portion of the second compression coil spring is supported on a second surface of the spring seat;
• the spring seat is interposed between the second end portions so that both the second end portion of the first compression coil spring and the second end portion of the second compression coil spring shift in position, relative to start points of effective windings of the two compression coil springs or end portions of element wires of the two compression coil springs, from each other in a circumferential direction around an axis of the two compression coil springs;
• the two compression coil springs are coaxially arranged through the spring seat;
• and
• the spring seat is movable in an axial direction of the two compression coil springs and in the circumferential direction around the axis of the two compression coil springs;
• and
• the spring seat rotates in the circumferential direction around the axis of the two compression coil springs together with the second end portions of the two compression coil springs when the two compression coil springs expand and shrink.