Box section reinforcement for filling free area, has cardboard section of corrugated paper cardboard and three longitudinal grooves arranged one below other, and height of cardboard section is changed by twisting at groove

摘要

The reinforcement has a cardboard section (1) of corrugated paper cardboard and three longitudinal grooves (2) are arranged one below the other. The height of cardboard section is changed by twisting at the groove and the cardboard section at ends is connected durably to a ring, where the grooves are formed as perforation lines and are intermittently broken.