Since ancient times, man has been trying to ease his work. To do this, he uses various devices. What are the simplest mechanisms? What varieties of these devices exist? What is the difference between simple and complex mechanisms? About this and much more - later in the article.
general information
Simple mechanisms (from the Greek. "Machine, gun") - devices that give gain in strength. Some of these devices appeared in antiquity. Simple mechanisms can be independent devices or be elements of more complex units. Depending on the type of construction, the scope of this or that device is also determined. The use of simple mechanisms greatly facilitates human activity. Such devices give a gain in strength. For example, a wedge that is driven into a log has more power than the impact on the device itself. Therefore, the tree quickly bursts in different directions. Along with this, the wedge hits from top to bottom, and parts of the logs are pushed to the sides. That is, in this case, there is also a transformation in the direction of movement.
Simple mechanisms. Examples
There are several types of devices:
Inclined plane
a) the screw is used in screws, like a drill in jackhammers, drills; can also serve as a lifting mechanism (Archimedean screw) ;
b) the wedge helps to increase pressure by concentrating the mass on a small area. It is used in pool, shovel, spear.
The lever is a device described by Archimedes. It can act as a trigger, a switch.
a) the gate is used for belt transmission and raising water from the well.
The wheel (invented in 3 thousand BC by the Sumerians) is an integral part of the gear system, it is used in transport.
The piston promotes the use of the energy of heated expanding gases or steam. This device is used in steam engines and firearms.
Gateway
This device is a drum (cylinder) to which the handle is attached. As a rule, it was used as a lifting mechanism for raising water from a well. The gain in strength obtained by using the collar is determined by the ratio of the radius of the circle along which the handle moves to the radius of the cylinder (drum) on which the rope is wound. The winch belongs to the modern type of gate. This device is a system that includes a cylinder and two gears of different radius. The gain in power that the winch generally gives is determined by the combined action of the two winches. Modern devices give a gain of forty to one hundred times.
Inclined plane
This simple mechanism is also often used when lifting heavy bodies. Strength gain is determined by the ratio of the length of the device itself to its height under the condition of low friction. Often, to create a large force (for example, for the work of an icebreaker or for chopping firewood) they use the form of an inclined plane - a wedge. Its action is based on the fact that with great effort in the direction of the butt, large forces are formed that are perpendicular to the side surfaces of the device. Another type of inclined plane is a screw. Like a wedge, this device is capable of changing the direction or numerical value of the applied force.
Simple mechanisms. Lever arm
This is a solid body that can rotate around a support (fixed). The smallest distance that separates the fulcrum and the straight line along which the force acts on the lever is called the shoulder of the force. To find it, you should lower the perpendicular from the fulcrum to the line of action of the force. The length of this perpendicular will be the shoulder. F1 and F2 - acting on the lever force. The shoulders acting on the device are L1 and L2. The lever is then in equilibrium when the forces acting on it are inversely proportional to the shoulders. This rule can be represented in the form of the formula: F1 / F2 = L1 / L2. This principle was established by Archimedes. This rule shows that a greater force with a lever can be balanced less. The force applied to one shoulder is so many times greater than that applied to the other, how much one shoulder is larger than the second.
How does a person apply devices today?
Simple mechanisms in everyday life are very common. So, it would be quite difficult to open the water tap if it did not have a small handle, which is a fairly effective lever. The same can be said about the wrench, with the help of which loosening or tightening the nuts or bolts is carried out. The longer the handle, the easier the action will be. So, when working with heavy or large nuts and bolts when repairing complex mechanisms, machine tools, cars, wrenches with handles up to one meter in length are used. The most ordinary door is also one of the types of devices considered.
If you try to open the door near its fastening, it will be very difficult. However, the farther the handle is from the hinges, the easier it is to open the door. A vivid example is the pole vault. Its length is about five meters. With the help of this lever and correctly applied effort, the athlete manages to fly up to a height of six meters. The long shoulder is approximately three meters. Levers are found in different parts of the human body and the body of the animal. This, in particular, the jaw, limbs. Common examples of levers are wire cutters, scissors for cutting metal or paper. Machines of various types also have devices in their design that make it possible to gain strength. For example, pedals or a
hand brake on a bicycle, sewing machine knobs, piano keys.
Integrated use of devices
Simple mechanisms are found in a variety of combinations. Combined devices include two or more parts. This will not necessarily be a complex mechanism - many simple devices can be considered complex. So, in the meat grinder there is a handle (collar), a screw pushing the meat and a knife-cutter (wedge). In a wristwatch, the hands are rotated using a system of gears having different diameters and in engagement with each other. One of the known combined simple mechanisms is a jack. It uses a combination of a gate and a screw.
Conclusion
As it became clear, simple mechanisms greatly facilitate the work of man. They may consist of one or more parts. Moreover, even with two or more elements, they can remain simple, but they can also be quite complex. Various aggregates, printing presses, engines include several parts. Among the elements there are levers, blocks, screws, axle wheels, inclined planes, and a wedge. All these devices work in a complex. Thanks to them, a person greatly facilitates work. The transfer of mechanical energy from one part of the device to another can be carried out in different ways. Chains, belts, gears or gears are considered the most common devices that facilitate the transfer of force and cause individual elements to move slower or faster in one direction or another. Complex and high-speed devices are controlled, as a rule, by electronic devices. Thanks to a special setting, electrical sensors show when it is necessary to turn on a particular mechanism, and they also monitor the correct and stable operation of the system.
Many devices came to the modern life of man from antiquity. People are constantly improving complex mechanisms, thus expanding the scope of their application. Undoubtedly, in everyday life of a person various devices occupy a very important place. Much cannot be imagined without the use of simple and complex mechanisms. The devices are widely used in construction, agriculture, in mining and in other areas of human activity.