The major limitation in rural road projects is that as the existing roads are narrow, for widening and building 50 per cent at a time, a small grader is required with a blade width of 8 ft to enable traffic to pass by while the road repair is going on. This gap will shortly be filled by LeeBoy, says Amarnath Ramachandran, VP - Product Engineering & Knowledge Management, LeeBoy. Excerpts of the interview.

Brief us on drive-train used and its unique features and advantages.
The drive train used on the LeeBoy machines comprises engines from Cummins, fully automatic 6F/3R power-shift transmissions with electronic transmission control unit from ZF, Germany, electro hydraulic fan drive systems on a 4-section fully aluminium heat exchanger and axles from Graziano/ZF.

The main features of the drive-train are:

• The automatic transmission to ensure that shifting of gears is based on actual torque demand from the ground rather than leaving it to unskilled operators. This eliminates wheel spin-out and stalling and enhances the clutch and tyre's life and also improves fuel efficiency.
• Lock-up clutch on the convertor ensures that optimal fuel efficiency is achieved when there is a rise in turbine speed. This happens during no-load conditions like reversing which is approximately 50 per cent on a motor grader's duty cycle.
• The electro-hydraulic fan drive ensures that the fan runs at an RPM, which is optimal as per the demands of the system and not running all the time at full power as is the case with engine driven fans.

Tell us about the electro-hydrostatic control used in your range.
Electro-hydraulic controls are used for gear shifting, park brake, clamp cylinder and fan drive system. The advantages are that on gear shifting, all instructions go to a canbus-controlled transmission control unit, which scans the input instructions, compares output parameters, checks logic and interlocks if any and executes the instructions. The park brake has an interlock wherein the transmission will not shift into gear unless the park brake is disengaged.

Tell us about the features to increase tractive effort while improving steering and side draft control. We have introduced an aggressive rear axle weight distribution to increase tractive effort. Also, while designing the Ackermann type steering system, we have ensured that sufficient steering torque is obtained by keeping adequate hydraulic pressure reserves.

What is the technology used to protect the draw bar, circle and moldboard from shock loads? The circle has a shear coupling/clutch. This limits the torque imparted via the blade striking a boulder or a hidden tree root and ensures that the circle rotation gearbox and the mouldboard are safe. In case the operator strikes a major obstruction with the full frontal area of the blade, a shear pin is provided on the tilt cylinder coupling to ensure that the draw bar is safe.