Tightness self-checking device for waterproof mobile phone protective case and method thereof

1 . A tightness self-checking device for a waterproof mobile phone protective case, comprising:

a waterproof mobile phone case cavity, wherein a front-mounted mobile phone case is provided on a front side of the waterproof mobile phone case cavity, a lower part of the front-mounted mobile phone case is provided with an opening;

a tightness self-checking mechanism, is mounted inside the opening; and

an engagement mechanism, is mounted at a front edge of the waterproof mobile phone case cavity;

wherein the tightness self-checking mechanism comprises a pressing frame, a fixing frame and a front transparent soft film, the pressing frame is placed inside the opening, retaining grooves are equidistantly provided in a front periphery of the pressing frame, the retaining grooves are all engaged with buckles, the buckles are all buckled at an inner edge of the fixing frame, a foldable soft rubber cavity is fixedly connected to a front side of the fixing frame, a pressing plate is fixedly connected to a front side of the foldable soft rubber cavity, and the front transparent soft film is mounted on an inner rear side of the front-mounted mobile phone case.

2 . The tightness self-checking device for the waterproof mobile phone protective case according to claim 1 , wherein the engagement mechanism comprises an edge-retaining ring, the edge-retaining ring is mounted at the front edge of the waterproof mobile phone case cavity, the edge-retaining ring is engaged with an edge-retaining groove, and the edge-retaining groove is provided at a rear edge of the front-mounted mobile phone case.

3 . The tightness self-checking device for the waterproof mobile phone protective case according to claim 1 , wherein an air squeeze space is formed between the foldable soft rubber cavity and the front transparent soft film.

4 . The tightness self-checking device for the waterproof mobile phone protective case according to claim 1 , wherein the pressing plate, the foldable soft rubber cavity, and the fixing frame are arranged in sequence in front and back.

5 . The tightness self-checking device for the waterproof mobile phone protective case according to claim 1 , wherein the retaining grooves and the buckles are rotationally connected.

6 . The tightness self-checking device for the waterproof mobile phone protective case according to claim 1 , wherein the front transparent soft film is squeezed by the foldable soft rubber cavity, thus bulging and contacting a mobile phone.

7 . The tightness self-checking device for the waterproof mobile phone protective case according to claim 1 , wherein a bottom groove is provided in a middle of a bottom surface of the front-mounted mobile phone case, a nail rod is provided inside the bottom groove, the nail rod is rotatably connected to one side of a movable arc buckle, another side of the movable arc buckle is mounted with a square buckle, elastic columns are mounted on sides away from the square buckle, springs are sleeved on outer surfaces of the elastic columns, a square groove is provided in a middle of a bottom surface of the waterproof mobile phone case cavity, through slots are provided on sides away from the square groove, grooves are provided on sides adjacent to the through slots, the square buckle is engaged with the square groove, and the elastic columns and the springs both penetrate the through slots and extend into the grooves.