US Patent 7419333 Drainage element

The machine for making the drainage elements employs a forming collar about the delivery chute for the aggregate so as to form a continuously supplied strip of netting into a tube to receive the aggregate. The machine may be run on an automatic basis without a need to stop the machine in order to replenish the supply of netting. A pair of tapes are used to secure the longitudinal edges of the tape together, one tape located inside the tube and the other tape located outside the tube.