Electronification for a hydraulic piling machine

Electronification for a hydraulic piling machine
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November 2016

 

The drilling and foundation equipment machinery manufacturer Soilmec and Bosch Rexroth brought unparalleled multi-functionality and easy use for a new hydraulic piling machine.

Heavy duty construction equipment, hasn’t traditionally been considered to be at the forefront of technological development. However, driven in part by health and safety, increased demand for multipurpose equipment and traceability, even the heaviest machinery now has innovative functionality more commonly associated with latest passenger car innovations than traditional construction equipment.

Soilmec’s latest SR-75 hydraulic piling machine demonstrates what can be achieved with variable, electronically driven components in tough construction environments. “One of the key drivers for technological development in our field has been the need for multi-purpose equipment”, states Mark Nelson, Soilmec’s Director in Great Britain. “Fortunately, this has also been reflected by key manufacturing partners, such as Bosch Rexroth, which provides multi-functioning interconnected drives controls, pumps and hydraulics.”

Five functions without compromise

The SR-75 achieves five highly specialized drilling functions: Kelly drilling for large diameter boreholes; Continuous Flight Auger (CFA) for instantaneous concrete injection; Cased Augured / Secant Piles (CAP/CSP) where additional casing support is required; Displacement Piles (DP & TCT), where the operator is looking to avoid soil removal; and Turbojet (TJ), which constructs a column of consolidated soil. In the past each of these specialist piling techniques would require a dedicated machine, with at most two to three functions covered by one vehicle. “Development at a component and systems level have meant that we are now able to achieve all five functions, without compromising any given discipline”, states Nelson.

For Kevin Follows, manager of application engineering at Bosch Rexroth, the five way multi-functioning approach and high level precision is the result of increased electronification: “The latest developments in variable electronic drives and controls mean we can program any number of functions at control level. Soilmec has taken this technology and scaled it up to create a machine that can comfortably cover a number of drilling disciplines, in a way that would be extremely difficult to achieve, if not impossible by taking a mechanical approach.”

Key to the SR-75’s design is the multi-functioning parallelogram at the front of the machine. This consists of four hydraulic cylinders that control the raising and levelling of the mast of the hydraulic rotary rig, as well as positioning and control of the rotary head. Designed by Soilmec engineers, the parallelogram allows the machine to automatically compensate itself by linkage instructed by Rexroth control valves. The Rexroth big block control cylinders, operate the rotary head, positioning and winch on the parallelogram from the main control cabinet.

The SR-75 control block that controls the functionality of the rotary head.

The SR-75 control block that controls the functionality of the rotary head.

 

Easy to use

The high level, multi-disciplinary functionality is coupled with an easy to use, highly responsive machine interface that allows precise control by operators. Steve Joynson, Plant and Fabrication Director of Cementation Skanska, one of Soilmec’s clients, explains: “From an end user perspective the machine operator can instruct the Rexroth controller to deliver the precise amount of pressure required via the remote relief and electro valves. Essentially the touch control interface interacts with Rexroth components to deliver precise functionality and this is something that we’ve expanded across the whole machine.”

High level functionality isn’t restricted to the cab, however, advanced telematics means real time data and drawings are provided to the contractors, with details on the pile, depth, diameter, amount of concrete used and steel added, as well as location.

Remote control

The Drilling Mate System (DMS), providing access to vehicles all over the world and monitoring systems are automatically provided for purchasers of the SR-75. For Nelson the benefits to the end user are clear: “All the information on each individual pile, can be accessed within a matter of minutes.” Not only does this provide the added reassurance at the time of installation that every­thing is being delivered to specification, but should the building begin to sink 30 years later the data is available and the contractor is covered. Likewise, if there was any additional foundation work that needed to be completed later on in the building’s lifetime, the background information is ready and available. “In practice this means within five to ten minutes of a pile being placed we know everything about it, we can also access the control screen, so that we can see exactly what the operator sees no matter where they are in the world,” Nelson states.

The telematics solution isn’t restricted to monitoring and recording, interoperability throughout the machine means that remote monitoring and control is well within the SR-75’s capabilities, as Nelson explains: “Remotely we can issue instructions from the computer to the pile modules, which then send electronic signals to Rexroth proportional control electro valves that ­direct oil to the control spool blocks, so the winches all start ­moving at a certain rate or speed.”

For Joynson the SR-75 marks a step change in remote monitoring and control. He comments: “In terms of operation this is the highest level of automation we have seen, enabling us to feed the work schedule into the machine and eradicating the potential for costly on-site errors. This is essential when working with the typically fine tolerances we operate under.”

 
The drilling mast stowed horizontally so the machine can be transported.

The drilling mast stowed horizontally so the machine can be transported.

The complete rotary head assembly with the two motors and gearboxes.

The complete rotary head assembly with the two motors and gearboxes.