Hinge structure

A hinge structure, comprising:

• a lower member which is to be attached to a container having an opening at an upper end of the container;
• an upper member which is to be attached to a lid for closing the opening of the container;
• a rotary shaft pivotably connecting the lower member and the upper member to each other;
• and
• a link mechanism connecting the lower member and the upper member to each other at a position different from a position of the rotary shaft, wherein
• the link mechanism includes
• a plurality of links pivotably connected to each other;
• and
• a spring mechanism of a torsion coil spring type configured to give the upper member spring force in a direction in which the lid is pulled up and opened,
• the plurality of links include
• a shaft member located at the position different from the position of the rotary shaft, and
• a first link pivotably connected to the lower member via the shaft member,
• the shaft member includes
• a first end protruding beyond the first link on one side, and
• a second end protruding on a side opposite to the first end,
• the spring mechanism includes
• a first torsion coil spring, and
• a second torsion coil spring,
• the first torsion coil spring is located to surround an outer periphery of the first end,
• the second torsion coil spring is located to surround an outer periphery of the second end, and
• the spring mechanism is configured to vary the spring force according to a position of the first link with respect to the lower member such that the lid rests in an arbitrary position.