Energy chains for drilling rigs: special flexibility under adverse conditions

Profile

• What was needed: E4 energy chain, RBR system, chainflex cables
• Requirements: An energy supply with high lateral stability was needed that could guide heavy cables and hydraulic hoses
• Industry: Construction machinery
• Success for the customer: Despite the complicated design of the drilling machine, the hoses and cables can be routed safely.

Problem

The focus is on mobile drilling rigs that produce sealing bases at depths of up to 30 metres. They do the main work in foundation construction and are subject to great stress. This applies to travelling to the immediate site over rough terrain and even more so to the actual drilling work. Vibration and impact, dirt and moisture, cold and heat place high demands on every single component.Under these tough conditions, the drilling rigs from KGS Keller prove their value - even though their design is anything but simple, and is instead extremely sophisticated. For example, the mast is moved by parallelogram kinematics. It can be extended horizontally straight up from its horizontal transport position, but can also be tilted in both directions and placed over the front axis of rotation completely perpendicular to the drilling position. In addition, it is possible to tilt the mast and with it the drill pipe in two axes, so that the operator can put up the drill pipe at an angle. 
All these movements have to be undertaken by the hydraulic and electrical cables, while also being well protected. An additional degree of freedom was recently required by new machine safety regulations. The drill head must now be fitted with a protective cage. This in turn must be tilted into the transport position so as not to exceed the height specification for road traffic. The designers at KGS Keller used this requirement to improve the guidance of the moving cables on the mast. Previously, two hose packages were sufficient. For the additional agility proper guidance had to be provided.

Solution

The decision was made for an igus E4.12 energy chain, which has also proven itself in other types of construction machinery. Harry Suckau, industry manager construction machinery at igus: "This type of chain is extremely robust. This is ensured, among other things, by the 'undercut design', which guarantees high lateral stability." This is particularly important if the mast tilts sideways because the drill head is positioned at an angle. The large diameter of the two hydraulic hoses for driving the drill is an indication of the forces the energy chain has to withstand in normal construction site operation. Patrik Berger: "In addition, the hoses, which have a considerable dead weight, move when pressurised." Robust cables for moving applications The signal cables guided in a separate chamber are less demanding in this regard However, UV radiation, cold and temperature differences are factors that can have a negative impact on their service life. This is why KGS Keller plays safe here and uses cables from the igus chainflex product range, which, like the energy chain, have been designed from the ground up for use in moving applications in tough conditions.

The maximum mast height of the KB 6 - that's the name of the drill, which is currently being produced in a small series - is 36 metres with auxiliary mast. The chain moves on the mast over a distance of 8.10 m, and the trough is made by Keller themselves. Since the protective cage on the drill head is folded downward in the driving position, the chain must be bendable in both directions where the basket is folded by 90°. This is no problem for the E4 chain: the so-called RBR elements are used in the respective zones. The abbreviation stands for "Reverse Bend Radius". Three of these elements are installed in the chains of the new generation of Keller drilling rigs.