Abstract: A can top end includes a disc-shaped panel having a disc-shaped flat section an outer periphery to be engaged with an upper end of a can body, and a stay-on type tab attached on the flat section of the panel. The disk-shaped flat section has a primary score to define a primary scored portion surrounded by the primary score and the flat section further includes a secondary score to define a secondary scored portion surrounded by the secondary score. The tab has a connecting portion rotatably connected to a center portion of the flat section around an axis perpendicular to the flat section and the tab has both a pull-up end and a push-down end. The primary scored portion is located below the push-down end of the tab to enable the primary scored portion to be opened by pulling up the pull-up end of the tab.

Abstract: An apparatus for discriminating and sorting out defective plastic bottle crates from sound bottle crates comprising driving means for urging an indenter or contact tip provided at the tip of a vibrating rod of an ultrasonic hardness tester into steady contact in indented state with a bottle crate, detecting means for detecting resonant frequency of said vibrating rod which is varied by the urging of said indenter or contact tip into steady contact with said bottle crate, and means for distinguishing and sorting out defective bottle crates from sound bottle crates in response to the resonant frequency detected by the detecting means.