Patent ID: 11891228
Assignee: CHANGZHOU BESTFULL MOULD & PLASTICS CO., LTD
Field: Handling (Mechanical engineering)
Classification: CPC B  G | IPC B  G

Claim 8:
9. The automatic air-extracting sealing box cover according to claim 1, wherein the sealing box cover is further connected with a pressure relief mechanism; the pressure relief mechanism comprises an electromagnetic valve and a pressure relief air tube; an air inlet of the pressure relief air tube communicates with a lower surface of the bottom cover, and an air outlet of the pressure relief air tube communicates with the atmosphere; the electromagnetic valve is connected with the pressure relief air tube, and the controller controls the electromagnetic valve to be turned on and off through a MOS tube switching circuit;
alternatively, the pressure relief mechanism comprises a shell, a air bubble film, a film fixing block, a first venting column, a compression spring and a second venting column;
the shell is connected to the box cover, a top end of the shell exposes on the upper surface of the top cover, and a bottom end of the shell is located at the lower surface of the bottom cover;
a cavity of the shell is a cylindrical cavity, a first through hole and a second through hole are opened at both ends of the cylindrical cavity; the cylindrical cavity communicates with the lower surface of the bottom cover through the first through hole and communicates with the atmosphere through the second through hole;
the second venting column runs through the first through hole of the cylindrical cavity into the cylindrical cavity, and the first venting column runs through the second through hole into the cylindrical cavity, a top end of the second venting column is fixed at a bottom end of the first venting column, and a venting hole penetrating through the first venting column and the second venting column is opened in the first venting column and the second venting column;
a first annular protruding ridge is provided at a lower outer wall of the second venting column, an outer diameter of the first annular protruding ridge is greater than an inner diameter of the first through hole; a sealing structure is provided between the first annular protruding ridge and the first through hole, and the first annular protruding ridge is located outside the cylindrical cavity; the compression spring is connected between the second venting column and the cylindrical cavity; a gap is left between an outer wall of the second venting column and an inner wall of the cylindrical cavity;
an opening end of the second through hole is connected with a bending edge facing an axis of the cylindrical cavity and an inner diameter of a circular through hole enclosed by the bending edge is less than an inner diameter of the cylindrical cavity;
a second annular protruding ridge is connected at a lower outer wall of the first venting column, the second annular protruding ridge is located in the cylindrical cavity and a sealing structure is provided between a top surface of the second annular protruding ridge and a bottom surface of the bending edge;
an outer diameter of the first venting column is less than the inner diameter of the circular through hole, the outer diameter of the second annular protruding ridge is less than the inner diameter of the cylindrical cavity and greater than the inner diameter of the circular through hole;
the air bubble film is covered on a top surface of the first venting column, the top surface of the first venting column is provided with a recess, the opening of the venting hole is located at the surface of the recess, a gap is left between the bottom surface of the air bubble film and the surface of the recess; the film fixing block is annular, the film fixing block is pressed on an edge of the air bubble film, and the edge of the air bubble film is sealingly connected with the recess;
the air bubble film is an elastic film made of an elastic material; and in a normal state, the air bubble film bulges in the middle; and when a bottom surface pressure of the air bubble film is less than a top surface pressure, the air bubble film is recessed in the middle; the middle position of the air bubble film is in the hollow of the annular film fixing block; and
when the elastic potential energy of the compression spring is minimum, sealing is performed between the first annular protruding ridge and the first through hole and sealing is performed between the second annular protruding ridge and the bottom surface of the bending edge.