مکانیزاسیون
ماشین آلات کشاورزی (agricultural mechanization)  

Inside This Article
1. Introduction to How Reel Mowers Work
2. Reel Mower History
3. Reel Mower Parts
4. Taking Care of Reel Mowers

You walk outside on a bright summer day, close your eyes and let the sounds of the season wash over you: birdsong, buzzing bees and the roar of lawn-mower engines. It wasn't always this way. Believe it or not, there was a time when cutting your grass didn't involve driving or pushing a small, gas-belching engine back and forth across your property.

iStockphoto.com/Brian Carpenter
Reel mowers cut down on noise and pollution around
the home.


The first lawn mowers were manual reel mowers, also known as cylinder mowers. All a person had to do was push one across the lawn, and the wheels would spin a cylinder of sharpened, grass-cutting blades.


The 20th century brought about the invention of gas-powered reel mowers and gas-powered rotary mowers, but not everybody leapt on board with the new technology. Many stuck with manual reel mowers, and many continue to use them today.


While the basic technology hasn't changed much in more than a century, manual reel mowers still boast a number of key advantages over their gas-guzzling and rotary decedents. Manual reel mowers:

Cost less than gas mowers.
Are less dangerous than rotary mowers.
Require little maintenance.
Are environmentally friendly.
Scoop and cut the grass blades, instead of tearing them like rotary mowers.
Produce little noise.
Are easy to transport and store.
Don't stir up dust or emit harmful fumes.
Don't fling debris around the yard.


The trade off? You wind up sacrificing speed and adding sweat. After all, your physical exertion moves a manual reel mower across the yard and also powers the blades. The amount of required force is generally the same as is required to push a larger rotary mower. However, the taller the grass, the more effort it takes to mow it. Tall weeds can be close to impossible to mow without first using a sling blade.


How did 19th-century inventors first apply textile mill technology to lawn care?

Reel Mower History

Reel mower history dates back hundreds of years. Prior to the early 1800s, a home's lawn maintenance fell largely to grazing animals or the manual use of scythes, swing blades and gardening sheers. For people with the time and inclination to manicure their lawns, this worked just fine. But the 19th-century world was experiencing rapid change. Europe was riding the wave of technological achievements and discoveries, known today as the Industrial Revolution.

Transcendental Graphics/Hulton Archive/Getty Images
This reel mower advertisement from the 1870s stresses the product's lightweight, easy-to-use design by demonstrating that even a little girl can use it.

Inventors throughout the 1800s made huge strides, from developing steam power to manufacturing machine parts. Inventors aimed their efforts at improving vital production processes such as coal mining, textile production and transportation. New technologies, however, always have a way of trickling down to even the most mundane uses.


British engineer Edwin Beard Budding made just such a connection between new technology and daily life. He observed a machine at a local textile mill that trimmed cloth with a bladed reel or cutting cylinder. Envisioning the possibilities of applying the technology toward lawn maintenance, he teamed up with engineer John Ferrabee. Together, they produced the world's first lawn mower in 1830.


The two engineers simply took the bladed reel, mounted it on a wheeled cart and arranged a system of gears to transfer wheel rotation to reel rotation. The mowers were heavy, cast-iron devices, but after Budding and Ferrabee's patents expired, other inventors began improving on the design. These new reel mowers were lighter and required less effort to push. Some inventors even replaced the gears with drive chains, like those on bicycles.


During the 1890s, other inventors attempted to add a power source to reel mowers. They tried both horsepower and steam power before small-engine technology advanced enough to become the standard. Today, most of the gas mowers used for home lawns are rotary mowers, which employ a horizontal, fan-shaped blade. While gas-powered reel mowers are still around, many of them are large, tractor-powered vehicles intended for the upkeep of sports fields and farms.


While gas- and electric-powered mowers have continued to evolve over the decades, the manual reel mower's basic design has remained the same. On the next page, we'll take a look at its different parts.

Reel Mower Parts

Manual reel mowers are reasonably simple devices; they depend on just a few moving parts and the basic application of force. The mower's overall construction is that of a small cart with a long handle. Most reel mowers feature two primary wheels on a single axle with either a bar of rollers or a set of smaller, secondary wheels in the rear. The rear roller or rear wheels simply provide balance, while the primary wheels provide the motion needed to turn the mower's bladed cylinder.


The best way to understand how reel mower parts work is to follow the flow of force through the mower.
A person pushes on the handlebars, applying force.
The applied force moves down the handle, pushing the mower forward on its wheels.
As the axle turns, it sends a pair of gears spinning. The first gear has a larger diameter than the smaller pinion gear. When a larger gear passes its rotation force, or torque, onto a smaller gear, the torque increases. This is why the blades of a reel mower turn much faster than the wheels. For more information on the physics of this, read How Gear Ratios Work.


The brush bar on the front of the mower bends tall grass, folding it over into the spinning cylinder blades. The spinning reel may look impressive, but it doesn't actually cut the grass on its own. All the cutting of the grass takes place where the spinning edges meet the stationary cutter bar in the rear of the mower. Think of it as the point of contact between the two blades of a pair of scissors. The cylinder scoops up the grass and moves it to the cutter bar the same way a barber uses a comb to position hair for snipping.

Most of the grass clippings then fall behind the mower, allowing for the use of a collection tray or bag on many models. Reel mowers differ drastically from rotary mowers in this respect, as the latter's fan-like blades actually tear grass, which can more easily expose the plants to disease [source: University of Tennessee].

Taking Care of Reel Mowers

Manual reel mowers are efficient and environmentally friendly, but it's still a slower option than using a gas mower. For this reason, manual reel mowers are practical only for yards of 8,000 square feet (about 743 square meters) or less [source: Reel Mower Guide]. That's approximately 0.18 acres. You also have to consider whether you're up to mowing the lawn frequently -- generally once a week during summer months. If you let your grass grow too tall, pushing a reel mower through it can prove difficult (or impossible). Let the yard go for a few rainy weeks, and you may wind up borrowing a gas mower or buying a swing blade.

Saul/Hulton Archive/Getty Images
Reel mowers require very little maintenance outside of regular sharpening.

Since the gears in a manual reel mower make the blades turn faster than the wheels, you don't have to run to keep the blade speed up. Still, the person pushing a manual reel mower supplies all the power, and a steady, reasonable pace is required to keep the reel spinning. Other than that, mowing the lawn with a reel mower is much like using a gas-powered push mower. Knowing what kind of grass you have and what mowing height and care that grass requires will help you to mow your lawn properly.

Taking care of reel mowers is easy. If properly cared for, reel mowers can last for decades. There are no oil changes or tune-ups required. The only steadfast rules for maintaining a reel mower are:
Clean the blades.
Wash off excess grass clippings.
Keep the mower out of the rain to prevent rusting.

To sharpen the blades, all you need are a grinding stone, grinding paste and some newspaper. The stone is little more than a rough file made of rock, and the paste has the gritty consistency of wet sand. Reel mower sharpening kits typically include both these items. First, use the grinding stone to file out nicks and burrs. Then, apply the grinding paste to the reel blades and cutter bar. By turning the reel backward, the gritty paste files away at the blades, sharpening the edges. The last step is simply to clean off the blades and test the cut on some newspaper to make sure the reel and cutter bar are close enough. If not, just make a few manual adjustments to the blade settings.

 HowStuffWorks WebSite

[ یکشنبه دوم اسفند 1388 ] [ 14:26 ] [ بهمن اسواری ]
.: Weblog Themes By Iran Skin :.

درباره وبلاگ

با سلام
این وبلاگ حاصل تحقیقات و گرد آوری های من در طول تحصیلم می باشد.
امید است که مطالب این وبلاگ برای پژوهش گران جوان مفید واقع شود.
استفاده از مطالب با ذکر منبع بلا مانع میباشد.
asvar.bahman@yahoo.com
امکانات وب