Joint of crib and method for locking and releasing the joint

A joint of a crib which has two joints connected to a top frame thereof, a linkage unit connected between the two joints and each of the joints connected between two side tubes of the top frame, the joint comprising:

• a mounting member having a bridge and two side plates extending from two ends of the bridge, a space defined between the two side plates;
• two operation units located in the space of the mounting member and each operation unit pivotably connected between the two side plates by a first pin, each operation unit having a support piece extending toward a first direction and a contact member extending toward a second direction, the support piece connected to the contact member, one of the two operation units having a pivot on a top of the contact member and the other one of the two operation units having an elongate hole defined in a top of the contact member, the pivot engaged with the elongate hole, each of the two operation units having a pressing section extending toward a third direction;
• a resilient member connected between the support pieces of the two operation units;
• two end pieces adapted to be respectively engaged with two respective distal ends of two side tubes of the top frame, each end piece having a notch which is located corresponding to the support piece of the operation unit corresponding thereto, a second pin extending through the side plates, the side tube and the end piece.