Greenville, S.C.-based Metromont Materials purchased three straddle cranes in 1995 to improve handling efficiency, but since they were equipped with only one pair of pulleys, the efficiency didn't carry over to architectural panel production, which usually requires an extra finishing step between casting and storage and thus a need for turning the product on its edge.
The auxiliary hoist system Metromont added to its cranes consists of two extra pulleys that hook onto a steel beam that has additional rigging. This configuration allows rigging to stay in place until the crane operator has loaded a panel onto the finishing rack. After lifting the panel a couple of feet off the bed with all four pulleys, the crane operator transfers all power to the auxiliary-hoist system, lifting it up and turning the panel 90 degrees.
The hoist system moves three panels to the finishing rack in the time it used to take to move one. In addition, setting those three panels on edge on a flatbed takes 20 minutes, compared with 45 minutes before.