Self-locking mechanism and folding sofa

A self-locking mechanism, configured to automatically lock a folding bedstead of a folding sofa, comprising:

• a support member, wherein the support member has a first end and a second end opposite to each other a locking member, wherein the locking member has a first connection portion and a locking portion, the first connection portion of the locking member is pivotally connected to the first end of the support member a drive member, wherein a first end of the drive member is pivotally connected to the first connection portion of the locking member a switch member, wherein the switch member has a second connection portion and a switch portion, the second connection portion of the switch member is pivotally connected to the second end of the support member and a second end of the drive member, and the switch portion is configured to drive the locking portion to rotate downwards and be pressed against the folding bedstead to lock the folding bedstead;
• wherein the support member has a horizontal plate and a vertical plate at the second end, a first end of the horizontal plate is perpendicularly connected to a middle section between the first end and the second end of the support member, a second end of the horizontal plate is perpendicularly connected to the vertical plate and extends downward, and the horizontal plate is installed on a sofa body frame of the folding sofa.