Joint angle adjustment mechanism

A joint angle adjustment mechanism, including:

• a base, having a center and two side boards opposite to each other, the center defining an axial direction, at least one of the two side boards having a plurality of toothed recesses relative to the center, the plurality of toothed recesses being arranged curvedly, an opening of each said toothed recess facing the center;
• two connecting members, respectively connected to the base, at least one of the two connecting members pivoted to the base;
• a positioning mechanism, including at least one adjustment mechanism, each said adjustment mechanism axially pivoted to the base about the center, each said adjustment mechanism including a positioning assembly, the positioning assembly including a slidable seat, a positioning member and an elastic member, the positioning member being slidably arranged within the slidable seat and optionally moving radially to be engaged with or disengaged from one of the plurality of toothed recesses, the elastic member being arranged within the slidable seat, two ends of the elastic member curling and bending relatively inward around an axis parallel to a circumferential direction of the base so that the elastic member has an e-shaped cross-section, the elastic member abutting against the positioning member so that the positioning member has a tendency to be radially engaged with one of the plurality of toothed recesses;
• wherein the slidable seat has a receiving space therein, a side of the slidable seat along the axial direction has an opening which communicates with the receiving space, the positioning member includes a slidable block and a pin member, the slidable block is slidably arranged within the receiving space, the pin member is inserted between the slidable seat and the slidable block, and the pin member is normally engaged with one of the plurality of toothed recesses due to the elastic member;
• wherein the slidable seat has at least one first hook portion in the receiving space, one of the two ends of the elastic member along a circumferential direction thereof forms at least one second hook portion, the at least one first hook portion and the at least one second hook portion hook with each other, and the other of the two ends of the elastic member opposite to the at least one second hook portion abuts against the slidable block.