Greutter Wilfried: Load-dependent braking device for conveying systems. Inventio, Kleeman Werner W, February 18, 1975: US3866725 (6 worldwide citation)

A load-dependent braking device for conveying systems having a primary brake with a fixedly adjusted braking moment and a secondary brake with variable braking moment, the braking moment of the secondary brake being adjusted in dependence on the loading moment acting upon a drive device or machine f ...