The VS (vehicle mounted single engine) sweeper is powered by a patent pending HGB2 hydrostatic gearbox.
A Single engine hydrostatic sweeper provides the best control during the sweeping operation and allows the driver to have infinite travel speed from 0 to 40kph. With the cruise control option the operator can set the ideal sweep speed and concentrate on sweeping, the hydrostatic control will maintain the set speed.
With a hydrostatic sweeper, the chassis is driven via the standard truck gearbox in transit mode and when the sweeper is required to sweep, the operator disengages the standard gearbox and engages the hydrostatic drive system. Maintenance is only required on one engine but as the single engine is working at high load more often, maintenance can be more expensive than a twin engine unit.
Once in Hydrostatic drive the sweeper will have a transit speed of up to 40kph allowing the operator to move away from traffic lights or relocate without having to disengage the hydrostatic drive. The operator has to stop the sweeping operation and come to a complete halt and apply the handbrake to change from hydrostatic drive to the chassis gearbox.
The Johnston HGB2 gearbox can handle high torque transmissions with engines up to 280hp allowing the sweeper to operate on steep gradients. Operators wishing to use 18ton sleeper cab chassis with high power engines can sweep efficiently without overloading the gearbox. Most environments will operate on chassis with engines around 180- 250hp.
The single engine sweeper uses the fuel tank from the chassis or the Johnston fuel tank. A 190litre fuel tank can be supplied with the VS range allowing longer on station time in comparison to the standard chassis fuel tanks supplied.
At maximum rpm the hydrostatic sweeper operates with a large 800mm diameter fan and fan speeds up to 3400 rpm. It has all the power needed to handle all environments and can perform better than the 55kw twin engine sweeper at maximum RPM but not as good as the 85Kw or 93Kw engine. It will use more fuel than a 55Kw twin engine sweeper at maximum revs but less than the 85 or 93Kw based on alike for like chassis engine. At lower revs however the hydrostatic sweeper will be less efficient than a twin engine sweeper and will use more fuel. It will use considerably more fuel in transit mode if left in hydrostatic drive.
The Hydrostatic drive system is lighter than the equivalent twin engine sweeper, allowing more pay load. On a 12 ton chassis the Hydrostatic truck the payload on a VS501 will be approx. 300kg more than its twin engine equivalent.
The Hydrostatic is ideal for built up areas such as towns and cities where sweeping speed and control are an advantage.