How does grass trimmer work

For the purpose of refining parks, squares, lawns near the house or the dacha plot, it is customary to use different types of equipment that effectively cut the grass and small bushes. The traditional lawn mowers, whose device did not allow mowing the grass close to the trees, in hard-to-reach places, on difficult landscapes, etc., replaced the more advanced and multifunctional units - trimmers. In the design of trimmers there may be differences: the location of the engine (above or below), as well as the type of drive: gasoline and electric.

Petrol trimmer

This type of trimmer has an indisputable advantage over the electric one, since it is not “tied” to an electrical outlet and can be used in places far from the electrical main.

Unit device

The market provided a huge number of models of gasoline trimmers. But despite this diversity, they are made by a single principle. At the very top of the trimmer is a gasoline engine (1), a fuel tank (2) and a starter (3) for manually starting the drive. The engine is connected to the working tool with a rod (4), inside which can be either a flexible shaft or a rigid one. The bar often consists of several parts (sections) and can be both collapsible and integral.

The handle (5) may have a different shape. It contains controls (6). The control module (6) is connected to the drive with a cable (7). A gearbox (8) is installed at the bottom of the device, the task of which is to transfer the rotation of the shaft to the spindle with a cutting tool (9) consisting of a reel with a fishing line (cord) or a special knife. For the user's safety, a shield (10) is installed above the cutting tool.

Also on the engine is placed another control element - a switch that changes the position of the air damper.

This switch makes it easier to start the unit. With it, you can quickly warm up the engine when the ambient temperature is lowered.

In turn, handle with controls has the following device.In the most prominent position of the handle is a button (1), interrupting the ignition circuit. It is used to stop the engine if the need arises. To control the carburetor valve, which is responsible for the amount of fuel supplied to the engine, a gas trigger (2) is used. The button (3), located below the “Stop” key, prevents accidental pressing of the “gas”. Until the safety button is pressed, the gas trigger will be locked. In order not to constantly hold the trigger gas with your finger, if you need long-term work of the trimmer, use the button-stop, which locks the control key in the pressed state.

Rigging

The cutting elements of the gasoline trimmer are usually bundled with the unit or purchased separately, depending on the type and complexity of the work that will be performed with it. In most models, as standard, there is a special reel (bobbin) in which a cord (fishing line) is wound, serving as a cutting tool.

The design of the bobbin allows you to adjust the length of the cord almost in a semi-automatic mode: just hit the ground with a stop and the lock from the inner reel is released.Further, due to the centrifugal force, during the rotation of the bobbin the cord comes out, and since there is a special knife on the protective casing, the excess edges of the fishing line are cut off.

The instructions to the spit indicate what thickness the fishing line should be. Usually its diameter is 2-3 mm, which is enough for cutting grass and shrubs with thin stems.

To mow thicker stems of plants (reed, sedge, shrubs), will require the use of metal knives and cutters. They, as a rule, differ in a form and quantity of the cutting surfaces (petals). There are mills, resembling a circular saw in appearance, which are successfully used on powerful units. Disc trimmer is usually used if you want to cut young growth of trees.

Also, to extend the functionality of the mowers, you can purchase (if not included in the package) special nozzles, as shown in the following figure.

You should know that such attachments can be installed only on a trimmer having a collapsible bar. In this case, the device may turn into:

• brush cutter,
• chain saw (you can cut down branches in the trees),
• brush (you can clear the tracks of snow and dirt),
• cultivator for tillage (surface).

Belts

The method of fixing the mower on your body while working should be taken seriously. This is because the weight of the unit with a gasoline engine can not be called small. And if this unit performs a large amount of work, then its weight causes fatigue in the back and the muscles of the user's shoulder girdle. Belts are backpack and shoulder type. In most trimmers for domestic use, shoulder straps with a soft and wide lining are used.

Principle of operation

The scheme of operation of the trimmer with a gasoline engine is as follows:

• using the starter starts the operation of the internal combustion engine (how the engine works is a separate topic);
• rotation from the crankshaft of the engine is transmitted to the gearbox via a clutch mechanism and through a shaft located in the rod;
• rotation of the gearbox is transmitted to the spindle, on which the cutting elements are fixed;
• cutting elements, due to the high speed of the spindle revolutions, cut the grass and bushes;
• spindle speed depends on the force pressing the gas button.

Electric trimmer

In the people, this type of mower is called the “electric scythe”.She also wears a shoulder with a belt and is very easy to operate.

Device apparatus

Electric mower differs from motokosy by the type of drive used in it, namely, the electric motor installed on it. Below is a diagram in which all the main components of the unit are clearly visible.

Such units have a lower weight than gasoline counterparts, and one button (ON / OFF) is used for control, which can be locked using the lock button if long-term operation of the unit is required.

Electric trimmers, can be produced with a different location of the engine.

1. The motor is located at the top of the unit. This arrangement of the drive is used in devices whose power can reach 1.4 kW. Due to this, tall grass, including wet grass, as well as small shrubs with thin stems are easily cut. Usually, the complete set includes electric fishing line and metal knife.
2. Motor at the bottom of the unit. With such an arrangement of the motor, the mechanical part of the apparatus is significantly unloaded, since the use of a gearbox and a shaft transmitting rotation from the motor is not required.The cutting unit is installed directly on the spindle of the electric motor, which increases the reliability of this design.

But still, such a structure of the unit with the absence of a gearbox affects the speed of the cutting tool. Due to the insufficiently high revolutions, such a unit can mow only young and not very thick grass.

Also exist cordless trimmer models. But these devices are not able to work for a long time, and besides, they are thin (used only for grass, not very thick and young). Since the battery needs periodic recharging, it is required to have a spare battery in order to use the unit more efficiently.

Cordless trimmers are often used because of their quietness and mobility, in places where it is impossible to use units that produce a lot of noise, for example, in hospitals, rest homes and hotels. They are also very convenient to use for cutting grass in hard-to-reach places and when working on areas with various obstacles - landscape design elements where an electric cable would interfere with movement.

Principle of operation

The principle of operation of the electric trimmer is distinguished by its simplicity:

• The power cable is connected to a 220V outlet with an electrical plug (it is very important that the socket be grounded);
• On the engine body, press the “ON” or “Start” button;
• after starting the engine, rotational movement from its rotor is transmitted to the gearbox via a flexible or rigid shaft embedded in the rod (the exception is units with lower engine position);
• The device is ready for operation after the spindle has reached maximum speed.

Electric trimmers have some limitations in operation, associated with the use of electric motors in them: you can not work in wet weather, mow the grass wet from dew or rain. Especially this rule applies to units with lower engine position.