Ride ons: mowers with rear engine and driver aboard
This type of groundkeeping machine is built for professionals as well as hobbyists and gardening enthusiasts. The technologies now in production have evolved greatly and are differentiated according to the use intended for these mowers. The cutting apparatus can be a blade revolving on a horizontal axis, helical blades welded in a horizontally rotating cylinder or reel creating a scissor-like cutting action or flails rotating around a horizontal rotor
A motor with a driver on board and an engine mounted behind the cutting deck is called a ride-on. The cutting deck is located in front or centrally and in both positions and laterally on the big machines. From the point of view of mower construction, this solution provides the best distribution of mass on the wheels for reducing compaction of the grass and in operation to give the driver better visibility without obstacles thanks to the rear mounted engine. The cutting deck of a ride-on can carry a blade revolving on a horizontal axis, helical blades welded in a horizontally rotating cylinder to create a scissor-like cutting action or flails rotating around a horizontal axis.
Types of cutting mechanisms
The three types of cutting mechanisms feature differing characteristics which must be identified because they strongly influence the choice of a mower in relation to quality and the use of the area mowed. Rotating deck blades turn at a regime of 3000-3500 r.p.m. to act as a whip at peripheral speed of 60-80 mt/s. The terminal sections of the well-sharpened blade must be in balance. Inside the cutting deck, the blade creates a partial vacuum which keeps the grass standing straight up to product a clean cut at a uniform height and the current of air expels the grass cut. To ensure rear or lateral discharge there must be the right ratio between the length and configuration of the blade and the depth and geometry of the housing. The height of the cut can be regulated but does not go below 25-30 cm. For mulching, or grass recycling, the grass mowed is returned inside the housing and finely chopped along the entire length of the cut grass thanks to the special configuration of the blade. Special cutting profiles can be mounted to facilitate mulching inside the deck. There are versions available for performing both functions of mowing and discharging the cut grass and mulching cutting.
In the mechanism with helical blades mounted on a horizontally rotating cylinder the blades are sharpened along their entire length and mounted on a cylinder, or reel, 0.5 to 1.0 mt in length and with a diameter of 110 to 200 mm. The number of blades varies from 4 to 12 and conditions the height of the cut. The scissors cut with this mechanism is achieved by the combination of the rotating reel and the fixed counterblade below.
Over the fixed, horizontal cutting blade set to the desired height of cut the fast-spinning cylinder of blades forces the grass past the cutting bar. Each blade on the blade cylinder forms a helix around the cylinder axis, and the set of spinning blades describes a cylinder. The rotation regime can be regulated between 1500 to 2000 r.p.m. An increase in the number of blades on the cylinder makes it possible, the speed of the mower being equal, to increase the cutting frequency to reduce the interval between one cut and another. To achieve good uniformity of the cutting height, the ratio of the interval and height of cut must move towards unitary. It should be pointed out that the peripheral speed of the blades and working at a mower speed of 8 km/h a 7 blade cylinder produces 60-70 cuts per meter and cutting intervals of 14-16 mm whereas with 11 blades the frequency rises to 100-120 cuts with cutting intervals of 8-10 mm. It can be seen that for mowing golf course greens at the typical uniform height of 3-6 mm an 11-12 blade system is required.
The mechanism rests on a rear smooth roller equipped with a rake and a rear splined roller. Regulating the height of the cut is performed with the two rollers. Compared to the mechanism with a horizontal blade, this version requires less power and enables operations on wet grass without clogging. On the other hand, these mowers need more maintenance and special equipment for sharpening blades and re-balancing the mechanism.
The flail mower mechanism is made up of a central drum or axis which rotates at a regime of 2000-2500 r.p.m. on which Y-shaped flails are attached by chain links or brackets. What is described as the sickle cut is performed by the outer edges of the flails which are usually staggered. The size of the flails used is determined by the type of grass to be mowed. Their thickness is around 1 mm for quality lawns and a cutting height of 20-25 mm and for operations on rustic laws and for tall grass their thickness is greater. The cut grass is expelled on the ground or discharged to the rear by the current of air generated by the flails. This mowing system with interchangeable flails means the mechanism is suitable for widely differing operations and work on tall grass.
The machine
Ride-ons are classified according to the cutting mechanism because any of them can be equipped with any one of the mechanisms described above. The mower with the rotating deck blade is the most widespread type on the market in Italy in models for hobbyists, semi-professionals and professional groundskeepers. Models in the first of these categories are equipped with a single front or rear cutting deck with work widths from 60 to 120 cm, powered by gasoline or diesel engines rated at 5 to 15 kW and the operator drives the mower with a steering wheel.
In the category of ride-ons built for professionals the machine may have a single or multiple cutting desk. Under the length of 210 cm, these mowers mount a single 1 to 3 blade cutting deck and bigger models are equipped with multiple decks and engines rated at 35 kW. A difference in the single deck models is front steering wheels with zero turning as opposed to rear steering wheels. The former are extremely maneuverable because the driving wheel can be blocked and the direction of rotation can be reversed. These machines mount engines at 12 to 25 kW and hydraulic transmissions and the mowers are usually driven by control levers.
Machines with three decks exceed 3.5 meters in length and are powered at 20-25 kW and beyond 35 kW. Operations can be performed with all three decks, with only the front or lateral deck or two, front and lateral. The blades are run hydraulically.
The mulching system can come as standard equipment or optional and the same applies to the collection bag with a capacity of around 200 liters for the smallest models or up to 600 liters for models with work widths of 150-180 cm. In the biggest models the cut grass is discharged with the help of a turbine.
The most common type of ride-on with helical blades is the version with three (triple) cutting units, two in front and one central. These machines enable to the user to mow with a single unit independently of the others. The number of blades per cylinder varies from 4 to 12 and the width of work is between 150 and 210 cm. Power is usually provided by a diesel engine rated at 15 to 30 kW. The mower can mount 3 or even 2-4 drive wheels and the blade rotor, lifting a single cutting unit and forward drive are usually run off a hydraulic system. The triple mechanism is designed for greenskeeping with rotors of diameters of less than 120 mm which carry 11-12 blades. Each cutting unit is provided with a bag located below the unit. For golf course fairways the typical helical blade mower mounts more than 3 floating-type cutting units for matching cutting to the profile of the terrain and keeping the borders of play easily visible.
Flail mower ride-ons are built in lengths of 85 to 130 cm and mount engines of 15-20 kW. The cutting system is mechanical or hydraulic and the drive is hydrostatic. The cut grass is generally discharged into a collection bag. Some ride-on versions with horizontal rotating blades can be transformed into flail mowers by replacing the rotating blade with flails.
Guide for selection
What most be considered in making a choice of a ride-on mower is the quality of the lawn to be mowed and the size of the area. The former factor leads to identifying the type of cutting mechanism required and the second determines the work capacity of the mower considered and the machine's work width. Ride-ons with helical blade cutting mechanisms are built for quality lawns, sports grounds and ornamental laws. It must be taken into account however that mowing should not remove more than one-third the height of the grass and this means that if the height is less than 6 mm the cutting mechanism must have a cylinder diameter of less than 120 mm mounting 11-12 blades and mowing must be more or less daily. For heights of 15-20 mm the number of blades can be smaller and the frequency of mowing cannot be less than a few days apart.
With grass heights above 20-25 mm the height of the cut of all three cutting units is ideal and, for making a smaller investment in the mower and facilitating maintenance, the ride-on preference is for a mower with a rotating horizontal deck blade. The option to mulch means frequent mowing at intervals of more than 8-10 days apart. Over the year, it might be opportune to mow with grass collection and also perform mulch mowing. For this, what is needed is a rotating deck blade mower capable of both operations. Ride-on with flail cutting are more flexible and can be adapted to various mowing conditions.
Reducing impact on the environment
It must be pointed out that these mowers powered by electric motors to reduce polluting emissions into the atmosphere are making progress. Studies and analyses in France, in fact, have shown that the impact of mowers powered by internal combustion engines is due to: 9% in manufacture; 1% in distribution; 85% in use; 5% in junking them. These figures account for the growing interest in electric motorization. According to a report published by Horticulture & Paysage in January 2013, analyses of the entire life cycle (LCA) of three types of motorization, gasoline, diesel and electric, in use 1,000 hours over three years covering 6,500 km the carbon footprints came to: 1,45 kg of CO2/km for gasoline; 0,83 kg of CO2/km for GPL; 0,40 kg of CO2/km for electric.
Moreover, for golf course greenskeeping manufacturers have been producing hybrid ride-on triple mowers for some time for combining internal combustion engines and electric drive.
