Manufacturing AUTOMATION

Boom lock safety

October 31, 2011
By Manufacturing AUTOMATION

Rexroth’s VBCN-R series of gravity lower load-holding devices, commonly called “boom lock valves,” gives machine builders the opportunity to refine control systems with the combination of two functions in one valve. The load lowering and hose burst safety compliance demanded by such regulations as ISO-8643/EN-474 can now be supplemented with full-range lowering speed control in the VBCN-R valves, the company says. In the past, the main directional valve controlled high-flow speeds, and the load-holding plus directional valve combination required “tuning” for optimum performance and safety compliance. The new VBCN-R series eliminates the need for highly synchronized opening of the two valves. The combination of low-hysteresis speed control, load limiting over-pressure protection and hose-burst safety in one single valve both streamlines the machine development process and provides cost-saving opportunity by potentially reducing directional valve spool cost. Energy savings are achieved through the low-side oil reclamation system of the VBCN-R valves. This functionality permits lowering with minimized oil supply from the pump, therefore allowing simultaneous functions, such as dipper and bucket cylinders, to operate with minimal horsepower draw on the engine and with decreased cycle times.

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