Patent ID: 8430420

Claim:
A security device for preventing unexpected folding for a child stroller, the child stroller comprising a side support assembly, a rear leg assembly, a frame positioning device, a front leg assembly, and a chair assembly, the rear leg assembly and the side support assembly being pivotally connected by the frame positioning device, the front leg assembly and the rear leg assembly being pivotally connected, the chair assembly comprising a seat tube and a seat plate, the seat tube being mounted on the frame positioning device, the security device comprising: a sleeve, the seat plate being disposed on the sleeve, the sleeve being sleeved on the seat tube in a slidable way and being pivotally connected to the front leg assembly, the sleeve having a first hole, the seat tube having a second hole, the first hole being substantially aligning with the second hole when the child stroller is unfolded; a seat-plate locking part, movably disposed on the seat plate, the seat-plate locking part having an end portion; and an elastic restore part, connected to the seat-plate locking part, when the first hole is substantially aligning with the second hole and the seat plate is weighted, the end portion being engaged in the first hole and the second hole simultaneously to constrain the sleeve and the seat tube from moving relatively; when the seat plate is un-weighted, the elastic restore part driving the seat-plate locking part to disengage the end portion from the second hole such that the sleeve is capable of moving relatively to the seat tube.