Door opening and closing device

A door opening and closing device comprising:

• a body case elongated in one direction;
• a retractable arm which is provided rotatable in the body case, rotates from an open state to a closed state, and has an arm axis as a rotational center thereof;
• a first slider which is provided at one side of the arm axis in the one direction in the body case and moves linearly in the one direction in conjunction with rotation of the retractable arm;
• a first link which is rotatable and directly connected to the retractable arm at an off-center position from the arm axis and is rotatable and directly connected to the first slider;
• a second slider which is provided at an opposite side of the arm axis in the one direction in the body case in such a way that the arm axis is located between the first slider and the second slider and which moves linearly in the one direction in conjunction with rotation of the retractable arm;
• a biasing member which is provided at the one side of the body case and biases the first slider in the one direction;
• and
• a damper which is provided at the opposite side of the body case and resists linear movement of the second slider,
• wherein the biasing member gives the retractable arm in the open state a biasing force in an opening direction, and when the retractable arm in the open state is rotated in a closing direction by a predetermined angle or more, the biasing member gives the retractable arm a biasing force in the closing direction, and
• when the retractable arm is rotated in the closing direction, the damper damps rotation of the retractable arm.