Select your location



xxx 2011-03-22

Lock and lower: Boom lock safety with expanded control

Lock and lower: Boom lock safety with expanded control

The reliability and safety of Rexroth’s market-leading boom lock valves is now enhanced to provide full-range, pilot controlled lowering speed regulation.

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.

Whether in earth moving, scrap handling or excavator attachment applications, for over 30 years users have appreciated the low-speed precision lowering control of Bosch Rexroth’s VBC series load-holding valves. This precision can now be realized across the full range of boom lowering speed without sacrificing the hose-burst response characteristics that ensure compliance with relevant safety regulations (after proper set-up and test.) 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.

Rexroth’s VBCN-R family of valves are designed for flow rates to 120 gpm and 6000 psi, however even higher flow rates can be achieved with customized solutions. Safety and precision, the ability to lock securely and lower smoothly and accurately, are values all machine operator’s prize – values Rexroth’s VBCN-R valves have the potential to maximize for all machine manufacturers.

Bosch Rexroth AG is one of the world’s leading specialists in the field of drive and control technologies. Under the brand name of Rexroth, the company supplies more than 500,000 customers with tailored solutions for driving, controlling and moving. Bosch Rexroth is a partner for industrial applications and factory automation, mobile applications and renewable energy.

As The Drive & Control Company, Bosch Rexroth develops, produces, and sells components and systems in more than 80 countries. In 2009 Bosch Rexroth, part of the Bosch Group, achieved sales of around $5.7 billion (4.1 billion Euro) with 34,200 employees. For more information, please visit:


Search press releases


Susan  Strauss
City Line Road 2315
18017 Bethlehem, PA
Phone: (610) 694-8352
Fax: (610) 954-8670