Patent ID: 7162839

Claim:
A slip stopper, in which, in front faces of a plurality of protruding portions protruding upwardly from a front face of a plate, concave portions are respectively formed in the plurality of protruding portions by shear planes which extend substantially perpendicular to the plate surface of the plate, each protruding portion has a shape that is high proximate to the center and lowers toward the plate surface of the plate, the concave portions are formed at the center of respective protruding portions in a condition where shear planes are used as inner circumferential surfaces, the concave portions have a closed bottom connected to the shear planes such that open through holes do not occur in the plate, and drain channels shaped into concave grooves lead from the center and lower to the front plate surface with an open and unhindered distal end that communicates with the front plate surface.