How Do Lawn Mower Blades Cut Grass?

In the old days, people never needed to worry about maintaining their lawns – the sheep, goats and cows would do the job for you, thanks to eating the grass every day. You can still see this if you go to the rural country, although these are increasingly in short supply thanks to the many modern lifestyles that surround our lives today.

In the world of today, you can still have a beautifully trimmed lawn – but you will need some help. That assistance can come in the form of robots, tractors, or lawn mowers. Regardless of the method you use, they all have something in common – the use of a motor that powers a blade, and does all the cutting.

The advancements in technology mean that smaller engines are becoming more powerful, and we are even seeing a move to green energy as many lawn mowers these days are battery or electric-powered types, and moving away from the gas types. In this article, we look at the method behind the process – and give you a better understanding of how your lawn mower does its job so well.

History of lawn mowers

The development of lawn mowers started in the early years after World War II, thanks to more people moving into suburban homes, which had larger plots to house a family comfortably. Thanks to the existence of these plots, the traditional push mower that had been in existence since the 1920s would not satisfy the new demands.

This resulted in the development of a new mower system that was more powerful than the push mower. Instead of using a mechanism of cutting grass like the manner a pair of scissors cuts paper, which push-mechanism mowers used, it instead uses a rotary mechanism. This involves a sharp, horizontal blade spinning around at high speed, and it cuts the grass when it hits the surface.

How they work

In the housing that holds the blade, also known as the deck, it will play a unique role in the maintenance of the lawn mower – it serves to prevent objects and grass from flying in multiple directions when the blade strikes it.

The structure of the blade and the underside of the motor means that the deck will move on four wheels, while the motor lies on top of it and a bag collects all the grass as it cuts.

The most basic version of rotary mower will have the handlebar attached, allowing you to push it when moving through your lawn and cutting the grass. There is a difference with a self-propelled version though – because of their design, they have a special transmission that directs the wheels to turn on. The entire system, in this case, will depend on the motor power, which means that it must be on for it to operate.

Self-propelled motors are great if you have a very large area to mow, and you need something with some extra power that can handle larger spaces.

In addition, there are also hovercraft lawnmowers that cater for those that want something special. These work through a mechanism of riding on a curtain of air, rather than the wheels you find in a rotary motor system. There are also robotic types, which do not need human intervention at all and can self-monitor their movements.

What to note

Regardless of the mower you decide to use, it is important to remember that some things need to happen so that the mower operates effectively.

First, the motor needs to be there, as well as a way of moving around the space, a rotating blade, and a method of getting rid of the clippings as the blade cuts the grass.

Different motors and their mechanism

Rotary types

These work using a system of internal combustion, where the engine uses four or two cycles. In the four-cycle one, the primary source of fuel is gasoline, but they have a lubrication system that is separate from the engine; while in the two-cycle type, the motor uses oil and gasoline.

In some cases though – especially with modern rotary motors – they use electric motors. These are powered through a rechargeable battery, a cord, or solar power in some cases.

A throttle joins to the motor, and is usually on the handlebar, and its job is allowing fuel to flow to the motor, as well as regulate the speed of the motor. If you accidentally release the throttle, the motor instantly shuts off to prevent injuries. You will also notice a vertical axle that joins to a large steel blade, and this hangs some inches above the ground.

The blade can either be curved or straight, but it does not matter – because the tip of the blade will do the cutting job.

Riding mowers

If you have a small lawn that is flat, you can use a rotary mower. If you have a hilly lawn, a mower of the self-propelled type will do. However, if you have a large lawn, the riding mower is the best choice.

They come in different sizes and with different horsepower needs, and you select one that fits the size of your lawn. In case of its workings, the driving process is similar to that of driving a car – since you guide the mower as you sit on its deck. In some models, you can have a steering wheel, others have levers that control the steering, while some have pedals that control braking and acceleration.

Before buying one though, you need to know exactly the purpose it will help you on. Its operating and maintenance costs are quite high compared to a rotary mower, so you need extra care when using it – I addition to the mower itself being very costly (the minimum price you can get it for is likely $1,000).

Final thoughts

Seeing the way a lawn mower works is very interesting, because of all the possible working mechanisms it can use when cutting grass or powering the engine. It also helps you know how to maintain it and repair it in case it breaks down, or in the regular maintenance schedule.


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