The Central Artery/Tunnel Project, said to be the largest and most technologically challenging highway project ever attempted, has advanced a number of construction innovations, among which is a versatile Gradall® Model XL 5200 excavator equipped with a boom-end Anver Corporation industrial vacuum system. Utilizing the strength of the vacuum system and the boom strength and versatility of the Gradall excavator, panels weighing up to 8,500 pounds have been picked up and positioned quickly. The vacuum system uses heavy steel flat vacuum pads which have 4-prong, extruded, closed-cell neoprene foam rubber seals that make contact with the panels. The seals' multiple prongs provide redundancy, which is necessary on the rough surfaces of stone and concrete panels. The pads are connected in parallel, and an attach/release solenoid valve opens and closes the vacuum supply line to this circuit. Each pad is also fitted with a shut-off valve for situations where the pad meets a cut-out opening in a panel.
The XL 5200's advantage on this unique job starts with its boom movements including tilting, rotating and telescoping action. The telescoping action, as opposed to conventional excavators' knuckle boom movements, allows the machine to work inside the tunnels where overhead space is limited. To further enhance the XL 5200's panel-handling capability, two more hydraulic-cylinder-powered motions were added at the boom end: 60° swing and 150° rotation (through a 4-bar linkage). As a result, only the Gradall Model XL 5200 can quickly and effectively pick up the massive panels in a horizontal or vertical plane, then maneuver, align, place and install them. Plus, these functions can be completed without the assistance of manual labor working outside the operator cab or within the vicinity of the boom movements.
For more information about Gradall excavators call (800) 445-4752.