Compound machines: what they are, composition, and examples.

Summary of the characteristics and parts of compound (or complex) machines, with examples.

Human development has led to great inventions, which have brought great advantages and improved the quality of life.

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

Washing machines, computers, cars... there are countless devices that we use in our daily lives on which we have become dependent and yet we do not fully understand how they work. All these devices are what are called complex machines, which in turn complex machines, which in turn are made up of so-called simple machines..

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

What are composite machines?

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

Composite machines have evolved as technology has developed. The first ones were mechanical, but with the discovery of electricity, electrical and composite machines were developed..

Virtually any type of device with a more or less complex mechanism is a compound machine. From something as small as a wristwatch to an aerospace spacecraft. The degree of complexity can also vary greatly, an example being the forklift, which is composed of only two levers.

Every time composite machines are used, their elements are subjected to friction, which generates wear and tear 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 properly.

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 elaborated can be achieved.. There are two types of these operators:

Mechanical operators

These are the elements that allow the machine to operate by converting force into motion. Their set is what is called a mechanism, the main operators of this type being the wheel, axles and gears. the wheel, the axles and the gears..

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

The axles are bars that connect the wheels and pulleys and allow the free movement of these but protected by a support.

Finally, gears are mechanical operators consisting of two circular toothed parts, the larger of which is called the crown and the smaller is called the pinion. They transmit circular motion by means of the movement and contact of their gearwheels.

Energy operators

This type 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 springs, batteries, batteries and motors..

Electric batteries have been manufactured in multiple shapes and sizes and allow the accumulation of energy that is stored for later use.

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

Simple machines

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

• Inclined plane
• Wedge
• Pulley
• Lathe
• Lever
• Screw

With the passage of time, and thanks to technological progress, new machines of this type have been developed which, in turn, have made it possible to develop more sophisticated and complex machines with specialized functions that could hardly be that could hardly have been imagined by the people of antiquity.

Examples of complex machines

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

1. Bicycle

This vehicle is a clear example of a compound machine.. It is propelled by the force exerted with the feet on the pedal, causing the wheels attached to the frame to rotate and allowing it to move.

2. Crane

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

This machine was one of the great creations of mankind, 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 a car or a very heavy piece of furniture. It works using a lever and can be mechanical or hydraulic..

4. Lock

It is a metallic mechanism that is incorporated in doors and drawers, which is composed 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

A device used to open metal cans.

6. Car

A vehicle in which, when the key is inserted into the ignition, the engine is activated which The axles that hold the wheels located at the bottom of the car can move and thus allow the car to move. and thus allow the car to move.

7. Radiocassette

Also called cassette tape recorder, this device that nowadays can be seen as a reminiscence of the past eighties music works by playing the recordings contained in the cassettes.

8. Turbine

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

9. Tractor

It is a self-propelled vehicle used to pull 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 and increase production, being one of the main elements of the agricultural revolution.

10. Washing machine

It is an electromechanical deviceThe washing machine, which can be both domestic and industrial, 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 is entering.

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

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

Bibliographical references:

• Beck, R. (1999). World History: Patterns of Interaction. Evanston, Illinois: 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.