Knife for opening shellfish, such as oysters, has hollow handle containing spring and retractable blade

摘要

Knife has handle (1) with projections (13) at blade end, and inner cavity (2), preferably cylindrical in shape, containing spring (6) to deploy blade (3) and closed by plug (4) at its other end. Handle can also have push-button to retain blade in its deployed position; in another it can incorporate percussion system which retracts and releases blade, with shock absorber (9) and hammer (11), operated by roller.