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Lawn mower: cutting systems

The most widely used mowers in France adopt the cutting system with rotating blade (s), the cutting cylinder being reserved for hand mowers or professional machines assigned to the maintenance of high quality lawns. (The picture does not necessarily reflect the drawing)

The mowers most used in France, as we have seen, adopt the vast majority of the cutting system by rotary blade (s), the cutting cylinder being reserved for hand mowers or professional machines assigned to the maintenance of high quality lawns.
If all cylinder mowers use the same system, there are noticeable variations between the different rotary mowers (s). Finally, the rotating Nylon wire system is widely used on small portable trimming machines and brushcutters.

Cutting cylinder

It is formed by the association of several spiral-shaped blades interconnected by a metal carcass, and arranged at equal distances from each other. These blades come rub on a against blade"Stuck" in some way the blade of grass and the edge. The cutting cylinder rotates under the effect of a drive, the counter blade, it is fixed and is part of the frame of the machine.
This training is ensured by direct connection with the wheels on the smallest of the lawnmowers, by chain (s) on the biggest ones or on the machines of professional type. The adoption of the cutting cylinder on the hand-held machines results from the ease of rotation of the system and its high inertia which allows it to turn virtually freewheeling at the slightest impulse.

This explains why a Cylinder Rider can benefit from a cutting width twice that of a rotary blade machine, and can be content with a motor half as powerful, hence a significantly more fuel efficiency and fuel efficiency. If one adds to this an exceptional quality of mowing, one could legitimately conclude to the indisputable superiority of the cutting cylinder.
That would be forgetting that mower of this type generally does not allow simultaneous collection of cut grass (except a few hand-held machines and some professional self-propelled small capacity front-mounted cars); but above all, it would be neglecting the fact thatwith a cylinder machine it is necessary to mow 2 to 3 times a week during the growing season. Finally, more complex in its design, the engine cylinder mower is, therefore, more expensive to purchase.

Rotary Lawn Mower Blade

Rotary Lawn Mower Blade

Rotary blade

Very widely adopted because of its simplicity, this system offers a satisfactory yield, facilitates the ejection or the collection of the grass, but does not ensure an optimal quality of cut, the blade cutting the grass more by its speed of rotation than by the edge of its extremities. This weakness has led manufacturers to develop improvements to avoid shredding grass cells in the cut, a defect that makes the lawn yellow in the days following the mowing, just before regrowth of the strand. We have of course worked on the quality of the steel blades, to delay the blunt edge, on their rigidity, but especially on their profile which plays a particularly important role here.
Some have developed a device consisting of a disk, on the periphery of which there are blades of short length, articulated on an axis allowing their retraction when they encounter an obstacle, pebbles for example. On machines with a normal blade, the shaft has a so-called "anti-scalp" washer, a kind of cup that avoids displacing the grass when one or more wheels fall into a hole and that the blade comes to rub against the ground.
Given the driving power required by this cutting system, it is difficult to rotate a blade of more than 80 cm with a motor 10 to 11 hp (order of power of the freestyle). Hence the adoption of 2 or 3 blades on machines that have a cutting width greater than 1 m. A belt system then ensures the transmission from the output shaft of the engine. These belts being relatively fragile because very exposed, it is prudent to buy a few in advance to not be out of order in case of breakage.

Rotary nylon thread

The rotation speed of the blade is the main factor in the work of a rotating blade: this led the manufacturers to replace it with a high-strength nylon thread. While tests on real mowers have been inconclusive, the system has been very successful on auxiliary equipment used for edge finishing, cleaning around trees and undergrowth. It is also associated with brushcutters.

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