US Patent 8973770 Cover for pressure cooker with locking pieces

A pressure cooker cover comprises a cover (1) and a float valve (2), wherein a seal ring (7) is installed in the inner edge of the cover while hooks (8) are installed in the two side edges of the cover. A push-pull device (9) which can move the hooks back and forth is mounted in the ends of the hooks. The push-pull device comprises a rotating base (9-1) arranged in the middle portion of the cover, a rotating shaft (9-2) and a locking piece (9-3) which is coupled with the rotating shaft (9-2). Sliding chutes (9-31) are provided at the two sides of the locking piece. Guide columns (8-1) which are slidingly matched with the sliding chutes are set at two ends of the hooks (8).