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Municipal and cemetery excavator maneuvers with Rexroth hybrid hydraulics

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July 2017

 

For the latest generation of its type APZ 531 municipal and cemetery excavator, HANSA is putting its trust in hybrid components from Rexroth.

The Lower Saxony company HANSA-Maschinenbau Vertriebs- und Fertigungs GmbH is the market leader for municipal and cemetery excavators. Hinrich Ropers, technical manager at HANSA knows that: “Cemetery maintenance and burials require quiet and careful operation.” Machinery needs to handle extensive working processes, complicated access routes, difficult ground conditions, and maneuvering in very tight spaces in an emotionally charged environment. This calls for excavators that can meet these requirements.

The APZ 531 excavator from HANSA has a width of just 1.30 meters and a telescopic boom with an impressive total projection of up to 7.30 meters. Magnifier

The APZ 531 excavator from HANSA has a width of just 1.30 meters and a telescopic boom with an impressive total projection of up to 7.30 meters.

 

The APZ 531 excavator is specially designed for this kind of flexible use, as well as for the municipal sector and gardening and landscaping. Its key feature is its continuous all-wheel drive, which guarantees constant mobility even with the toughest ground conditions. Depending on the type of ground, the driver can switch between front wheel, all wheel, and crab steering. On the road between two working locations, the excavator can travel at an impressive speed of 40 kilometers per hour thanks to its hydrostatic Rexroth drive. The main components of the travel drive are an A4VG axial piston variable pump in the closed circuit and an A6VM variable displacement motor. With a width of just 1.30 meters, the excavator has a telescopic boom with an impressive total projection of up to 7.30 meters. The APZ 531 has a double shell grab as standard, which is continuously rotatable through 360 degrees. For work in the municipal sector, the Lehnhoff quick-change system can be used to switch to a backhoe and trench bucket.

HANSA and Bosch Rexroth have been cooperating intensively since the 1980s. The previous model from 2009 featured the Rexroth A10VO working pump and the M4 load-sensing control block. To meet emissions directives, HANSA installed the exceptionally quiet, Euro 6 certified 150 HP Iveco diesel engine. For the transition to the latest version, which complies with the new Tier IV final, hybrid hydraulics were introduced in 2015. The outstanding characteristic of the Rexroth hybrid solution with integrated priority valve for the steering is the combination of load-sensing and LUDV technology. The load-sensing components such as the M4-12 control block come from Germany, while the LUDV slices are from the Italian subsidiary Bosch Rexroth Oil Control. The load-sensing components are designed for high flow rates (up to 150 liters per minute) and high pressures of up to 420 bar, while the EDC valves in the LUDV setting can handle flow rates of up to 60 liters per minute and pressures up to 310 bar. The priority oil supply to the load-sensing consumers enables motion superimposition between the rotating mechanism and working functions without the need for sophisticated electronic control.

Variable hydraulic control

When ever a mobile working machine’s tasks involve precise working and sensitive control of complex motion sequences, the focus falls on the stable and regulated control of the hydraulic oil flow rate. Precision, sensitivity, load independence, and safety are guaranteed at all times. The load-sensing technology with optimized section pressure compensator enables the operator to proportionally actuate each individual consumer with the required precision – regardless of the load and the position of the excavator. The result is excellent operating convenience and thus high productivity. With an appropriate choice of valve slices (sections), an M4 block can control up to 20 functions, for example, additional attachments such as loppers, augers, or breaker hammers in the case of the HANSA excavator.

Safe and reliable

Further advantages of the consistent modular design are simplified commissioning and a more user-friendly service, as all assembly groups and individual parts can be replaced without dismantling the complete system. This fits well with the HANSA concept. Easy maintenance and repair are a must in municipal building yards. Hinrich Ropers says: “We have deliberately stayed away from electronic operating elements and are using hydraulic pilot control from Rexroth instead.” Easy access to maintenance-relevant components further simplifies the day-to-day work. This lays the foundation for a fault-free daily working routine.