Chainsaw are the hungry, violent machines that instantly bring down those huge trees that have taken years (if not decades) to grow. It’s such a powerful yet compact machine that can do more than you can imagine.
You might think that a machine that fell the trees just for wood is destructive. But think again… These machines have actually saved lives by so doing. You always meet the buzzing sound of a chainsaw in a natural disaster and emergency situations.
You can also imagine how forest management could be like if these machines didn’t exist- they help in thinning and clearing the trees, improving their overall long-term health and those of creatures that reside in them.
What mechanism does this petite powerhouse use to do so much work?
Let’s take a closer look
What is A Chainsaw?
A chainsaw consists of two main parts: a small, one-cylinder gasoline (or sometimes electric) engine and a saw blade built into the chain and spread around the long metal guide bar.
The chain looks a bit like the bicycle chain- it runs around the sprocket. These gear wheels have around 30 sharp teeth made from hardened steel alloy.
Inside the engine, as the piston is moving in/out of the cylinder, it will push an attachment rod that will then turn the crankshaft. The crankshaft will then turn the connected gears through the centrifugal clutch (explained below) to any of the gear wheels on which your chain is mounted- and the chain spins around the bar!
How A Chainsaw Works
Literary speaking, your chainsaw convert gasoline to sawdust. In scientific principles, it converts chemical energy (in the chainsaw oil you use) into mechanical energy that’s needed to turn the massive tree trunks into logs, sawdust, heat, and noise.
Below is a simplified step by step explanation of how a chainsaw works
- To set your chainsaw ready for work, you ought to start by adding fuel to the gas tank of your chainsaw. The fuel bears chemicals that will be converted into mechanical energy essential for running the machine. To keep it light and a nice, a typical gas tank holds around 0.5litres of chainsaw oil (that translates to 1.1US liquid pints).
- After you input the fuel, it will pass through the carburetor where it actually mixes with the air.
- The air-fuel mixture is then transferred to the cylinder. This cylinder works much like the car engine (with the exception that it features a push-pull/two-stroke action rather than the highly sophisticated four-stroke used in the cars).What goes on inside the cylinder? Well, the air and fuel mixture is ignited by a spark plug (actual sparkling occurs here). And in so doing, it burns and releases the stored chemical energy while pushing the piston back and forth. The piston has a bore diameter of around 45mm and a stroke of around 33mm. In other words, it’s less than half the size of car engine piston and will only move half as far.
- There are the connecting rod and crank that converts the back and forth movements of the above piston into a rotational motion.
- The drive shaft then transfers the power produced to the centrifugal clutch.
- As you know, your chainsaw engine runs all the time. But you don’t want it to run while you are not cutting any wood- this is not only dangerous but also a waste of energy. The clutch easily overcomes this issue by connecting the chain and engine when the engine speed is high (when you pull on the throttle) and halts the chain from spinning when the engine speed is low (when the machine is idling).Let’s explain the working principle of the centrifugal clutch a bit. The clutch is simply the device that makes or releases a mechanical connection between the engine and the machine it’s running. It acts as a switch that lets the engine run the entire time (which is way better than switching it on and off all the time) without necessarily driving the machine it’s attached to. The chainsaw centrifugal clutch will automatically engage when your chainsaw engine is spinning at high speed or when it’s cutting the wood. Likewise, it disengages when your engine is idling or running slowly. The clutch is simple and comprises of only a few parts. There’s the inner driver shaft that links directly to the engine and spins all the time. There’s also an outer rim suited around it. There exist mechanical arms in between. These are connected to the inner shaft and fly outward at high speeds. They lock the inner and the outer parts of clutch together.
- With the help of the gears, the power is then transferred from the clutch to the sprockets holding the chain.
- This power is then responsible for the spinning of your chainsaw chain. The chain will spin around the long guide bar- usually made of sturdy steel plate- spitting out sawdust as it splits trees!
This is a dead simple, step-by-step explanation of how you chainsaw works. As you’ve noted, the process just involves the conversion of the input fuel into a form of energy that the machine can use to run. The energy is the transferred to the chain which spins to cut wood logs in seconds.
The chainsaw has made our lives easier, more so because you can cut huge tree branches in a matter of seconds. Imagine doing the same work with an ax for a whole day? We can only thank the brains behind this great invention.