Compound machines: what they are, composition, and examples

Human development has allowed great inventions, which have been a great advantage and improvement in the quality of life.

What a few centuries ago was unthinkable today can be achieved by simply pressing a button, and that is that electronics have been one of the greatest inventions of humanity.

Washing machines, computers, cars... there are endless devices that we use in our day to day on which we have become dependent and, however, we do not fully know how they work. All these devices are what are called complex machines, which in turn are made of so-called simple machines.

In this article we are going to address what these types of machines consist of, going back to their components and giving some examples to see it more clearly.

• Related article: "13 technological and digital tools for psychologists"

What are compound machines?

Compound machines are those mechanical devices which have been formed from two or more simpler machines which are connected in series. Being connected in this way, when one of these parts of the compound machine is activated, the The rest work in a coordinated way, being able to offer together a function that individually cannot could.

Compound machines have evolved as technology has developed. The first ones were mechanical, but with the discovery of electricity, electric and mixed ones were developed..

Virtually every type of device that has a more or less complex mechanism is a compound machine. Whether it's from something as small as a wristwatch or an aerospace ship. Also the degree of complexity can be very variable, being an example of this the wheelbarrow, which consists only of two levers.

Every time compound machines are used, their elements are subjected to friction, which generates wear as time goes by. For this reason, these types of machines require certain care, such as good lubrication and being sent to a mechanic in case they do not work correctly.

Composition of compound machines

Compound machines work in steps; through which different types of operators work so that the function for which the mechanism was developed can be given. There are two types of these operators:

mechanical operators

They are the elements that allow the operation of the machine, converting force into movement. Its set is what is called mechanism, being the main operators of this type the wheel, axles and gears.

The wheel is a circular piece that rotates around an axis. In itself it is considered a simple machine, being one of the most important inventions of humanity, thanks to the fact that it has been used in countless more complex machines.

The axles are bars that join the wheels and the pulleys and allow their free movement but protected by a support.

Lastly, gears are mechanical operators that consist of two toothed circular pieces in which the larger one is called the crown and the smaller pinion. It allows to transmit the circular movement through the movement and contact of its toothed wheels.

energy operators

These types of operators are in charge of storing energy or force and transforming it into another type so that the device can be activated and perform its function. Some examples of these are docks, batteries, cells and motors..

Electric batteries have been made in multiple shapes and sizes and allow energy to be stored for later use.

Motors are devices that transform energy into another type, so that the machine can use it and fulfill its function. There are electric, steam and fuel engines.

• You may be interested in: "Artificial Intelligence vs Human Intelligence: 7 differences"

simple machines

Simple machines were widely studied during the Renaissance. At that time, the classification for this type of machine consisted of 6 types:

• Inclined plane
• Cradle
• Pulley
• Turnstile
• Lever
• Screw

With the passage of time, and thanks to technological progress, new machines of this type have been developed which, in turn, have allowed the development of more sophisticated complex machines with specialized functions that people of antiquity could hardly imagine.

Examples of complex machines

These are several examples of compound machines that show all the typical characteristics of these goods.

1. Bicycle

This vehicle is a clear example of what a compound machine is.. It is driven by the force that is exerted with the feet on the pedal, causing the wheels attached to the frame to turn and allowing movement.

2. Crane

It is a machine that allows you to raise and lower heavy items or whose movement can be complicated. The loads are lifted by being placed on a hook that is at the end of a rope or chain..

This machine was one of the great creations of humanity, since it facilitated the construction of tall buildings and its origins date back to Ancient Greece.

3. car jack

It is used to lift objects that have a great weight, such as the car or a very heavy piece of furniture. It works using a lever and can be mechanical or hydraulic..

4. Lock

It is a metal mechanism that is incorporated into doors and drawers, which is made up of a part that prevents them from being opened.

By incorporating the element that deactivates it, either a key or in the most recent versions a fingerprint, the lock is unlocked and allows access to the interior of the house or the contents of the drawer.

5. Can opener

It is a device used to open metal cans.

6. Car

Vehicle in which, when the key is inserted into the ignition, the engine is activated which allows the axles that hold the wheels located at the bottom of the car to move and thus allow movement.

7. Radio toca cintas

Also called a cassette recorder, this device that today can be seen as a reminiscent of the past eighties music works by reproducing the recordings that contained the cassettes.

8. Turbine

They are machines through which a fluid passes continuously. and this gives kinetic energy to the turbine through the blades that are attached to it. Thus, the turbine spins, working as a motor. Its basic element is the wheel.

9. Tractor

It is a self-propelled vehicle used to tow or push trailers. They can be used in different sectors: agriculture, nautical, construction, earthmoving...

Thanks to its creation, it has made it possible to significantly reduce labor as well as increase production, being one of the main elements of the agricultural revolution.

10. Washing machine

It is an electromechanical device, which can be both domestic and industrial, which is used to clean clothes.

In its central part it has a drum with holes that, when the washing machine is activated, turns while water mixed with detergent enters.

The drum moves thanks to the action of an electric motor which is transmitted traction by means of pulleys.

Some more modern models have made it possible to improve the washing experience by making the clothes already dry during the process of eliminating residues in the fabrics.

Bibliographic references:

• Beck, R. (1999). World History: Patterns of Interaction. Evanston, Ill.: McDougal Littell.
• Strizhak, V.; Igor P.; Toivo P. (2004). Evolution of design, use, and strength calculations of screw threads and threaded joints. HMM2004 International Symposium on History of Machines and Mechanisms. Kluwer Academic publishers.