A folding joint comprising a first connecting head, a second connecting head, a
handle, and an adjustment rod. The first connecting head and the second connecting head are hingedly connected to one another on one side, one end of the
handle is hingedly connected to the other side of the first connecting head, and the other end of the
handle is provided with a positioning pin. The other side of the second connecting head is provided with a clamping axis. One end of the adjustment rod is firmly connected to the positioning pin, and the other end of the adjustment rod is firmly connected to the clamping axis. The handle is provided with a self-
locking mechanism. The self-
locking mechanism comprises a locking block, a compression spring, and an adjustment push rod. The locking block is provided with a locking slot and a guide bevel.wherein the locking slot is configured to receive the adjustment rod, and the guide bevel is provided at the upper end of the locking slot. The locking block is further provided with a connecting portion, wherein the connecting portion is provided with a threaded hole, the surface of the adjustment push rod is provided with a threaded portion, the adjustment push rod is screwed to the connecting portion, one end of the adjustment push rod is provided with a knob and the other end is provided with an
optical axis, wherein the adjustment push rod is provided with a stepped surface at the intersection of the threaded portion and the
optical axis, the compression spring is sheathed on the outer surface of the
optical axis, one end of the compression spring presses against the stepped surface, and the other end presses against the inside of the handle.