Hybrid Rail Head Profile Grinding Machine

• The operator makes contact with the rail next to the joint
• and presses a button on the programmable logic controller (PLC) to define the datum level or the depth stopper - from this home position, the grindstone can only move upwards.
• This effectively eliminates undergrinding.
• Then the grinder scratches along the other end of the grinding section and raises the home position in case a discrepancy is found.
• Rough grinding is done in several cycles – the free of play grinding wheel feed is controlled by pressing the toggle switch.

Finishing is achieved by a method patented by Robel:

• The home position level stored in the PLC corresponds to the dimensions of the original grindstone.
• As the grindstone wears down, the joint will protrude from the home position level by 0.2 to 0.4 mm
• The operator can level out the difference by setting the PLC to finishing mode (between 0.1 and 0.9 mm in steps of 0.1 mm).
• Upon pressing a button, the grindstone will move down to and stay at the defined position.
• Upon releasing the button, the grindstone will perform a very short stroke to automatically return to the home position.
• What you get is a replicable grinding pattern with smooth and pointed facets.

• Half the machine weight
• Easy handling in an ergonomic posture
• No combustion engine near the grinding point
• A compact e-motor and lightweight construction grant an unobstructed view of the grinding point
• Constant speed for improved surface finish
• Reduced vibrations for an optimised grinding pattern
• No wearing parts
• Operator is exposed to significantly less exhaust gas, heat and noise
• Reduced fuel consumption

The combustion engine in the machine is replaced by an enclosed brushless DC motor which, owing to its neodymium solenoids, is very small and provides a much higher power density than a combustion engine or a conventional asynchronous electric motor.

Thus, ROGRIND HF's energy chain comprises:

• combustion engine GX200,
• non-wearing generator,
• proprietary charge controller, and
• Supercap

and in the machine:

• drive controller and
• BLDC electric motor supplying 7 kW peak power

The petrol engine runs at some distance from the grinder, i.e. at the other end of the spark-proof drop cable where a separate, portable unit (Power Pack 70.02 made up of motor, generator and Supercap) is located. Due to its lower rating, the motor is subject to fewer load variations which makes its work more efficient at lower fuel consumption.

Thus, the new drive solution protects the combustion engine from grinding dust and the operator from exhaust fumes and noise. The greatest advantage, though, is the reduced weight and the ensuing ergonomic plus: considering that you have to carry them to the site, place them on the track or lift them, two time 50 kg are less than one time 100 kg.

When grinding a joint, the grindstone revolves at a constant speed while the machine permanently moves forward and backward. All force and power go into the grinding action. Although the machine runs at full throttle when the direction of motion turns from feed to return stroke, the grindstone as such hardly needs any power at all.

Up to now, the energy supplied by the combustion engine at that time was lost. With the new hybrid technique, the excessive energy is collected and stored via the generator directly in compact electrolytic capacitors (Supercaps).

As opposed to batteries, the Supercaps work at any ambient temperature down to -30° while boasting a service life of about 10 years. This efficient energy storage cell combines with a BLDC motor which allows the extra boost of energy to be output to the rail.

The result: in order to optimise the work output without losing any of the grinding power, you now just need a GX200 engine which is 9 kg lighter than the previous GX270.