Agricultural tractors are the source of what type of vibration? What types of vibration are there? According to the source of vibration

1. According to the method of transmission to humans, they are distinguished:

1.1. General vibration transmitted through supporting surfaces to the body of a sitting or standing person (through “contact points”);

1.2. Local vibration transmitted through human hands. ·

2. According to the source of vibration:

2.1. Local vibration that is transmitted to a person from hand-held power tools (with engines), manual controls of machines and equipment.

2.2. Local vibration that is transmitted to a person from hand-held non-motorized tools (without motors), for example, through the handles of hammers or from workpieces (hand grinding). ·

2.3. General vibration 1st category. This is a transport vibration that affects a person in self-propelled and trailed vehicles and other vehicles when moving across terrain, agricultural backgrounds and roads.

Sources of transport vibration are tractors, bulldozers, cars, combines, etc.

2.4. General vibration 2 categories. This is a transport-technological vibration that affects a person at the workplace of machines moving on specially prepared surfaces of production premises, industrial sites, and mine workings.

Sources of transport and technological vibration include: excavators (including rotary), industrial and construction cranes, machines for loading (charging) open-hearth furnaces in metallurgical production; mining combines, mine loading machines, self-propelled drilling carriages, various track machines, concrete pavers, floor-mounted production vehicles. This category should include everything that moves on rails or other tracks (tram, train, interfloor elevator). It is necessary to use the main feature of the group: “specially prepared surfaces of production premises, industrial sites, mine workings.” This circumstance is relevant when searching for sanitary standards for assessing vibration in the driver’s cabin of a train, elevator, tram, overhead or gantry crane.

2.5. General vibration 3 categories. This is technological vibration that affects people at workplaces of stationary machines or is transmitted to workplaces that do not have sources of vibration. The main condition for determining this type of vibration: the source is fixedly fixed on the flooring, ceiling, platform, etc.

b) Category 3 b. In workplaces of warehouses, canteens, utility rooms, duty rooms and other industrial premises where there are no machines that generate vibration (a permanently fixed source of vibration is located in an adjacent room);

c) Category 3 c. At workplaces in plant management premises, design bureaus, laboratories, training centers, computer centers, health centers, office premises, workrooms and other premises for mental workers (a permanently fixed vibration source is located in remote rooms).

Note that on sea and river vessels, vibration belongs to the technological category, since the main source of vibration is the ship’s engines, which are fixedly fixed to its hull.

If the engine of a car and other vehicles is idling, then in this case the vibration on the cabin floor and the driver’s seat belongs to technological category 3a. When vehicles move, their drivers and drivers are affected by transport vibration.

In this regard, the question arises, what kind of vibration should be measured in cars?

It all depends on the goals and objectives of the study. Thus, most often in the certification of workplaces for working conditions, the main task of vibration measurements is to assess the technical condition of the engines and the entire vehicle.

The fact is that the certification procedure is carried out in a short time in the absence of a standard road surface (autodrome). Therefore, there are no conditions for correct measurements of transport vibration. It’s one thing to measure vibration in a car cabin on an asphalt road, and another thing to measure it on a dirt road.

On the other hand, certification of workplaces aims to optimize working conditions, which largely depend on the technical condition of the transport unit. If its condition does not meet the requirements, then based on the results of measurements of process vibration (at idle speed), there is someone to file a claim with - the employer. Claims for excess transport vibration against the employer due to poor-quality road surfaces are not rational.

If the purpose of the study is to study the adverse effects of transport vibration, then measurements are carried out while the vehicle is moving. This task most often arises when a vehicle moves through a limited area (by shuttle), for example, when transporting minerals from a mining quarry. Another example: the work of a tractor driver during plowing, land planning, etc.

Let's discuss the situation. In the clinic of the institute, the driver A. of a powerful BELAZ car was found to have persistent damage to the intervertebral discs. Diagnosis: occupational disease associated with exposure to general (transport) vibration.

This man worked removing ore from the Uchalinsky quarry for 26 years. During this period, while driving a car, he went down to the quarry and rose from the quarry five to six times a shift. Our research - measurements of transport vibration (on the cabin floor and seat) and noise on this limited path were carried out at the beginning, middle and end of the route, in the warm season, in rainy and dry weather. They showed a significant excess of noise and vibration standards.

The sanitary and hygienic characteristics compiled based on the results of certification of workplaces indicated that the noise levels in the BELAZ cabin exceeded the maximum permissible, and the levels of transport vibration were below permissible.

The question arises: is such a situation possible? There is only one source of noise and vibration waves - the car engine, and these waves must be related to each other in intensity, frequency, amplitude, etc. It turned out that the sanitary document used the results of measurements of technological vibration on different cars. Such a hygienic description of the working conditions of an employee with a suspected occupational disease is erroneous, since it does not take into account the real working conditions of the driver, and does not meet the main task - to rationally assess the impact of general vibration on the employee’s health.

Assessing the technical condition of different vehicles is aimed at identifying faulty equipment, but not at assessing the impact of this equipment on the employee.

Questions about the hygienic selection of vibration measurement points in cars, tractors, bulldozers and other machines depend on their design.

Currently, there are no longer vehicles with intensely vibrating handles, steering wheels, and pedals. Therefore, the main points for measurements should be on the floor and seat. And the main task of the measurements is to assess the vibration damping properties of the seat, which is very important for the characteristics of the working conditions of drivers, tractor drivers, and machinists.

2.6. The standards for technological vibration in communal facilities are based on human subjective sensations and are therefore presented as acceptable levels.

Based on the source of vibration, there are two categories.

2.6.1 Technological vibration in residential premises and public buildings from external sources: urban rail transport, vehicles, industrial enterprises and mobile industrial units (during the operation of hydraulic and mechanical presses, planing, cutting and other metalworking mechanisms, piston compressors, concrete mixers, crushers, construction machines, etc.);

2.6.2. Technological vibration in residential premises and public buildings from internal sources: engineering and technical equipment of buildings and household appliances (elevators, ventilation systems, pumps, vacuum cleaners, refrigerators, washing machines, etc.), as well as built-in retail establishments (refrigeration equipment) , public utility and consumer service enterprises, boiler houses, etc.

2.7. General technological vibration is also divided into two categories (3d, 3d):

2.7.1. Technological vibration in residential premises, wards of hospitals, sanatoriums;

2.7.2. Technological vibration in administrative and management premises.

3. According to the direction of action, vibration is divided in accordance with the directions of the axes of a three-dimensional orthogonal coordinate system:

3.1. Local vibration is measured along the axes of the orthogonal coordinate system X. Y. Z.

Figure 7 illustrates the directions of local vibration measurements in two cases: when the hand covers a spherical surface (lever) and when the hand covers the tool handle. The X axis is parallel to the axis of the vibration source coverage area (handle, cradle, steering wheel, control lever held in the hands of the workpiece, etc.). The Y axis is perpendicular to the palm, the Z axis lies in the plane formed by the X axis and the direction of delivery or application of force (or the axis of the forearm when no force is applied).

Figure 7 – Orthogonal coordinate system for measuring local vibration.

Changing the position, for example, of a hammer handle from horizontal to an angle of 45 0 does not change the order of the indicated axes - it all depends on the scope of the object.

3.2. General vibration is also measured along the axes of the orthogonal X,Y coordinate system. Z., as shown in Figure 8. In this case, the X axis is the direction from the back to the chest (sagittal projection). Y axis – from the right shoulder to the left (frontal projection). The Z axis is perpendicular to the supporting surfaces of the body at the points of contact with the seat or floor.

Figure 8 – Orthogonal coordinate system for a worker sitting or standing.

Note that:

2. Often the vertical axis carries the greatest vibration energy Z. If oscillatory energy predominates along the lateral axes, the machine will come off the foundation, and the car will overturn,

3. Perform vibration measurements on the flooring of the room (room) along the lateral, horizontal (frontal and sagittal) or otherwise - along the lateral axes X and Y, almost impossible,

4. When measuring general vibration, the accepted axes do not shift relative to space (lying or standing, sitting person),

5. When measuring local vibration, the axes shift relative to space, but depending on the scope of the object. So, if the horizontally located steering wheel is moved by 30-40 degrees, then the axis Z will change its direction from the vertical by the same amount.

4. Based on the nature of the vibration spectrum, the following are distinguished:

4.1. Narrowband vibrations, in which the controlled parameters in one 1/3 octave frequency band are more than 15 dB higher than the values in the adjacent 1/3 octave bands;

4.2. Broadband vibrations - with a continuous spectrum more than one octave wide.

5. According to the frequency composition of vibrations, they are distinguished:

5.1. Low-frequency vibrations (with a predominance of maximum levels in octave frequency bands of 1-4 Hz for general vibrations, 8-16 Hz for local vibrations);

5.2. Mid-frequency vibrations (8-16 Hz - for general vibrations, 31.5-63 Hz - for local vibrations);

5.3. High-frequency vibrations (31.5-63 Hz - for general vibrations, 125-1000 Hz - for local vibrations).

6. According to the time characteristics of vibrations, they are distinguished:

6.1. Constant vibrations, for which the value of the normalized parameters changes no more than 2 times (by 6 dB) during the observation period;

6.2. Non-constant vibrations, for which the value of the standardized parameters changes by at least 2 times (by 6 dB) during an observation time of at least 10 minutes when measured with a time constant of 1 s, including:

6.2.1. Vibrations that fluctuate over time, for which the value of the normalized parameters changes continuously over time;

6.2.2. Intermittent vibrations, when human contact with the vibration is interrupted, and the duration of the intervals during which the contact occurs is more than 1 s;

6.2.3. Pulse vibrations consisting of one or more vibration impacts (for example, shocks), each lasting less than 1 s.

As you can see, the classification of vibrations is a very complex system, which is very difficult to understand.

The first task in the practice of vibration measurements is to determine its type for choosing standards. To do this, you can use a simpler diagram, which is shown in Figure 9.

Figure 9 – Brief classification of industrial vibration

Vibration– these are mechanical oscillatory movements of a system with elastic connections. Vibration is characterized by a frequency spectrum and kinematic parameters such as vibration velocity and vibration acceleration or their logarithmic levels in decibels (dB).

Types of vibrations

Vibration is classified as follows:

1. By method of transmission to humans:

local vibration transmitted to the worker’s hands;
general vibration transmitted through the supporting surfaces of the body while sitting (buttocks) or standing (soles of feet).

2. By frequency composition:

low frequency vibration (with a predominance of maximum levels in the octave bands of 1-4 Hz and 8-16 Hz, respectively, for general and local vibration);
mid-frequency vibration (8-16 Hz for general vibration, 31.5 and 63 Hz for local vibration);
high frequency vibration (31.5 and 63 Hz for general vibration, 125-1000 Hz for local vibration).

3. In the direction of vibration impact - in accordance with the direction of the axes of the orthogonal coordinate system:

For general vibrations, the direction of the Xо, Yo, Zо axes and their connection with the human body is as follows: the Xо axis is horizontal from the back to the chest; Yo axis – horizontal from the right shoulder to the left); Zl – vertical axis perpendicular to the supporting surfaces of the body at the points of contact with the seat, floor, etc.
For local vibration, the direction of the axes Xl, Yl, Zl and their connection with the human hand is as follows: axis Xl - coincides with or parallel to the axis of the location of the vibration source (handle, cradle, steering wheel, control lever, workpiece held in the hands, etc.); The Yl axis is perpendicular to the palm, and the Zl axis lies in the plane formed by the Xl axis and the direction of supply or application of force, and is directed along the axis of the forearm.

4. By the nature of the spectrum:

narrowband vibration - in which the controlled parameters in one third-octave frequency band are more than 15 dB higher than the values in adjacent third-octave bands;
broadband vibration – with a continuous spectrum more than one octave wide.

5. According to temporary characteristics:

constant vibration for which the value of vibration velocity or vibration acceleration changes by no more than 2 times (6 dV) during the observation period;
fickle vibration (oscillating, variable, pulsed), for which the value of vibration velocity or vibration acceleration changes by at least 2 times (by 6 dB) during an observation period of at least 10 minutes.

Production sources local vibration are machines of impact, impact-rotary and rotational action. Local vibration occurs during sharpening, emery, grinding, polishing work performed on stationary machines with manual feeding of products, as well as when working with hand tools.

General vibration According to the source of occurrence there are: transport, transport-technological and technological.

Drivers of transport vehicles (tractors, self-propelled agricultural machinery, trucks, earthmoving machines, etc.), as well as operators of transport and technological equipment (excavators, cranes, mining machines, concrete pavers, etc.) are exposed to general and local vibration. Low-frequency, jerky vibration of a random nature is transmitted to workplaces, which occurs during the movement of machines on an uneven surface or from the operation of moving parts of mechanisms. Vibration resulting from engine operation is transmitted to the driver's workplace, including the controls.

To sources technological vibrations This includes equipment whose operation is based on the use of vibration and shock (vibration platforms, vibration stands, hammers, dies, presses, etc.), as well as powerful electrical installations (compressors, pumps, fans, some metalworking machines, etc.).

The impact of increased vibration levels on the human body

Vibration is one of the factors with significant biological activity. The nature, depth and direction of functional shifts on the part of various body systems are determined primarily by the level, spectral composition and duration of exposure to vibration.

Worker health disorders caused by local or general vibration consist of damage to the neurovascular, neuromuscular systems, musculoskeletal system, metabolic changes, etc. With all types of vibration disease, changes in the central nervous system are often observed, which are associated with a combined effect vibration and intense noise that constantly accompanies vibration processes.

According to statistics, 1/4 of identified occupational diseases are associated with exposure to vibration and noise. The highest incidence of vibration disease is recorded in the heavy, energy, transport engineering, coal industry and non-ferrous metallurgy.

Preventive measures to reduce vibration levels

A set of preventive measures that reduce vibration levels of equipment, reduce the time of contact with it and limit the influence of unfavorable accompanying factors in the production sphere includes hygienic standards, organizational, technical and therapeutic and preventive measures.

The main document regulating the parameters of industrial vibrations is Sanitary Standards SN 2.2.4/2.1.8.566-96 “Industrial vibration, vibration in residential and public buildings.” They contain the classification of vibration, methods for hygienic assessment of vibration, standardized parameters and their permissible values.

Sanitary rules and regulations SanPiN 2.2.2.540-96 “Hygienic requirements for hand tools and organization of work” establish requirements for hand-held machines (weight), weight perceived by the operator’s hands when performing work operations, pressing force required for work in nominal mode, force pressing triggers. This document also contains rules for organizing work with hand tools and preventive measures.

There are a number of state standards that regulate the hygienic parameters of vibration of machines and equipment.

Basic methods and means of vibration protection

The main methods and means of vibration protection are:

eliminating direct contact with vibrating equipment through the use of remote control, industrial robots, automation;
reduction of vibration intensity directly at the source;
the use of vibration damping, dynamic vibration damping, active and passive vibration isolation;
rational organization of work and rest;
creation of integrated teams with interchangeability of professions;
use of personal protective equipment;
organization of active differentiated medical examination of workers in vibration-hazardous professions;
thermal procedures for hands in the form of hydrotherapy or dry air heating;
mutual and self-massage of the arms and shoulder girdle;
industrial gymnastics;
ultraviolet irradiation;
vitamin prophylaxis.

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Tolyatti State University

on life safety on the topic:

"Industrial vibration"

2nd year students

Faculty of Foreign Languages

Oshkina O.V.

Vibration - this is the mechanical oscillatory movement of a system with elastic connections; movement of a point or mechanical system, in which the values of at least one coordinate alternately increase and decrease in time.

The reason for the excitation of vibrations is the unbalanced force effects that occur during the operation of machines and units. The source of such an imbalance may be heterogeneity of the material of the rotating body, a mismatch between the center of mass of the body and the axis of rotation, deformation of parts, as well as improper installation and operation of equipment.

Basic vibration parameters: frequency, displacement amplitude, speed, acceleration, vibration period.

In industrial environments, vibration in the form of simple harmonic oscillations is almost never encountered. When machines and equipment operate, a complex oscillatory motion usually occurs, which is aperiodic, pulsed or jerky in nature.

Classification of vibrations affecting humans.

Vibration by mode of transmission per person(depending on the nature of contact with vibration sources) are conventionally divided into:

General vibration transmitted through supporting surfaces to the body of a sitting or standing person;

Local vibration transmitted through human hands.

Note. Vibration transmitted to the legs of a seated person and to the forearms in contact with vibrating surfaces of work tables is referred to as local vibration.

In industrial environments, there is often a combination of local and general vibration.

By source of occurrence vibrations are distinguished:

Local vibration transmitted to a person from hand-held power tools (with engines), manual controls of machines and equipment;

Local vibration transmitted to a person from hand-held non-mechanized tools (without engines), for example, straightening hammers of various models and workpieces;

General vibration of category 1 – transport vibration affecting a person in the workplace of self-propelled and trailed machines, vehicles when driving on terrain and roads (including during their construction).

Sources of transport vibration include:

Agricultural and industrial tractors, self-propelled agricultural machines (including combines);

Trucks (including tractors, rollers, etc.);

Snow plows, self-propelled mining rail transport;

General vibration of category 2 - transport and technological vibration affecting a person at the workplace of machines moving on specially prepared surfaces of production premises, industrial sites, and mine workings.

Sources of transport and technological vibration include:

Excavators, industrial and construction cranes, machines for loading open-hearth furnaces in metallurgical production;

Mining combines, mine loading machines;

Track machines, concrete pavers, floor-mounted production vehicles;

Sources of technological vibration include:

metal and woodworking machines, forging and pressing equipment, foundry machines, electrical machines, pumping units and fans, equipment for drilling wells, drilling rigs, machines for livestock farming, grain cleaning and sorting (including dryers), chemical and petrochemical industry installations and etc.

a) at permanent workplaces of industrial premises of enterprises;

b) in workplaces in warehouses, canteens, utility rooms, duty rooms and other industrial premises where there are no machines that generate vibration;

c) at workplaces in plant management premises, design bureaus, laboratories, training centers, computer centers, health centers, office premises, workrooms and other premises for mental workers;

General vibration in residential premises and public buildings from external sources:

Urban rail transport (shallow and open subway lines, trams, rail transport) and motor transport;

Industrial enterprises and mobile industrial units (when operating hydraulic and mechanical presses, concrete mixers, crushers, construction machines, etc.);

General vibration in residential premises and public buildings from internal sources: engineering and technical equipment of buildings and household appliances (elevators, ventilation systems, pumps, vacuum cleaners, refrigerators, washing machines, etc.), as well as built-in retail establishments (refrigeration equipment) , utility service enterprises, boiler houses, etc.

By frequency composition vibrations emit:

Low-frequency vibrations (1-4 Hz for general vibrations, 8-16 Hz for local vibrations);

Mid-frequency vibrations (8-16 Hz - for general vibrations, 31.5-63 Hz - for local vibrations);

High-frequency vibrations (31.5-63 Hz - for general vibrations, 125-1000 Hz - for local vibrations).

According to time characteristics vibrations emit:

Constant vibrations, for which the value of the normalized parameters changes no more than 2 times (by 6 dB) during the observation period;

Non-constant vibrations, for which the value of the standardized parameters changes by at least 2 times (by 6 dB) during an observation time of at least 10 minutes when measured with a time constant of 1 s, including:

a) vibrations that fluctuate over time, for which the value of the standardized parameters changes continuously over time;

b) intermittent vibrations, when human contact with vibration is interrupted, and the duration of the intervals during which contact occurs is more than 1 s;

c) pulse vibrations, consisting of one or more vibration impacts (for example, impacts) each lasting less than 1 s.

The impact of vibration on the human body.

The human body is considered as a combination of masses with elastic elements that have natural frequencies, which for the shoulder girdle, hips and head relative to the supporting surface (standing position) are 4-6 Hz, for the head relative to the shoulders (sitting position) - 25-30 Hz For most internal organs, natural frequencies lie in the range of 6-9 Hz.

Local low-intensity vibration can have a beneficial effect on the human body, improve the functional state of the central nervous system, accelerate wound healing, etc., but with an increase in the intensity of vibrations and the duration of their exposure, changes occur, leading in some cases to the development of occupational pathology - vibration disease.

General vibration with a frequency of less than 0.7 Hz, defined as pitching, although unpleasant, does not lead to vibration disease. The consequence of such vibration is seasickness, caused by disruption of the normal activity of the vestibular apparatus. When the oscillation frequency of workplaces is close to the natural frequencies of internal organs, mechanical damage or even ruptures are possible. Systematic exposure to general vibrations with a high level of vibration velocity leads to vibration disease, which is characterized by disturbances in the physiological functions of the body associated with damage to the central nervous system. These disorders cause headaches, dizziness, sleep disturbances, decreased performance, poor health, cardiac dysfunction, visual disturbances, numbness and swelling of the fingers, joint disease, and decreased sensitivity.

Maximum permissible level (MAL) of vibration- this is the level of a factor that, when working daily (except for weekends), but not more than 40 hours a week throughout the entire work experience, should not cause diseases or health problems detected by modern research methods during work or in the long term of life present and subsequent generations.

Compliance with vibration limits does not exclude health problems in hypersensitive individuals.

Permissible level of vibration in residential and public buildings- this is the level of the factor that does not cause significant concern in a person and does not cause significant changes in the indicators of the functional state of systems and analyzers that are sensitive to vibration.

Main regulatory legal acts regulating the parameters of industrial vibrations are:

"Sanitary standards and rules for working with machines and equipment that create local vibration transmitted to the hands of workers" No. 3041-84 and "Sanitary standards for vibration of workplaces" No. 3044-84.

Currently, about 40 state standards regulate technical requirements for vibration machines and equipment, vibration protection systems, methods for measuring and assessing vibration parameters and other conditions.

Persons at least 18 years of age who have received the appropriate qualifications, passed the technical minimum according to safety rules and have passed a medical examination are allowed to work with vibrating machines and equipment.

Work with vibrating equipment, as a rule, should be carried out in heated rooms with an air temperature of at least 16 0 C and a humidity of 40-60%. If creating such conditions is impossible (outdoor work, underground work, etc.), then special heated rooms with an air temperature of at least 22 0 C should be provided for periodic heating.

Vibration is defined as an oscillatory process that occurs during a periodic displacement of the center of gravity of a body from its equilibrium position, as well as during a periodic change in the shape of the body that it had in a static state. Vibration occurs due to vibrations of parts of devices, machines, communications and structures caused by imbalance of rotating parts, pressure pulsations during the transportation of liquids, etc.

It is believed that the range of vibrations perceived by a person as vibration in direct contact with an oscillating surface, lies in the range (12–8000) Hz. Oscillations with a frequency of up to 12 Hz are perceived by the whole body as individual shocks. At frequencies greater than (16-20) Hz, vibration is accompanied by noise.

It should be noted that under certain conditions vibration has a beneficial effect on the human body and is used in medicine to improve the functional state of the nervous system, accelerate wound healing, improve blood circulation, treat radiculitis, etc., the beneficial property of vibration is used to intensify certain production processes, for example, vibration compaction of concrete, soil, unloading bulk materials from containers, etc.

However, in many cases in production environments exposure to vibration can cause disruption of the mechanical strength and tightness of devices and communications, cause accidents, and also lead to various disorders of human health. Vibrations cause numerous reactions in the human body, which cause functional disorders of various organs and systems of the body.

In its simplest form vibrations is vibration acting according to a sinusoidal law. The main parameters of a sinusoidal oscillation: frequency - in hertz; displacement amplitude – A in m or cm; speed – in m/s; acceleration a - in m/s 2 or in fractions of the acceleration of gravity - 9.81 m/s 2. The time during which one complete oscillation occurs is called the oscillation period T (s).

Conventionally, the zero level of vibrational velocity is taken to be 5·10 -8 m/s, corresponding to the root-mean-square vibrational speed at a standard sound pressure threshold equal to 2·10 -5 N/m 2 , and the zero level of vibrational acceleration is taken to be 3·10 - 4 m/s 2.

Vibrationclassified according to a number of characteristics.

By transmission method It is customary to distinguish vibration:

local (local), transmitted through hands (when working with manual machines, controls);
general,transmitted through the supporting surfaces of a sitting or standing person and causing a concussion of the entire body.

By the nature of the spectrum

narrowband, for which the controlled parameters in the 1/3-octave frequency band are more than 15 dB higher than the values in the adjacent 1/3-octave bands;
broadband , which do not meet the specified requirement.

By frequency composition vibrations are divided into:

low frequency with a predominance of maximum levels in the octave bands of 8 and 18 Hz (local), and 1 and 4 Hz (general);
mid-frequency – 31.5 and 63 Hz (local), 8 and 16 Hz (general);
high frequency – 125, 250, 500 and 1000 Hz (local), 31.5 and 63 Hz (general).

According to time characteristics local vibrations are divided into:

permanent,for which the vibration velocity changes no more than 2 times (by 6 dB) during an observation period of at least 1 minute;
fickle, for which the vibration velocity changes by at least 2 times (by 6 dB) during an observation period of at least 1 minute.

In its turn inconsistent vibrations are divided into:

waveringin time, for which the level of vibration velocity continuously changes over time;
intermittentwhen the operator’s contact with vibration during work is interrupted, and the duration of the intervals during which the contact occurs is more than 1 s;
pulse, consisting of one or more vibration impacts (for example, impacts), each lasting less than 1 s.

General vibrationDepending on the source of its occurrence, they are divided into the following three categories:

transport vibration , affecting a person in the workplace of self-propelled and trailed machines, vehicles when they move across the terrain. Sources of transport vibration include tractors, agricultural machines, cars, snowplows, self-propelled rail vehicles, etc.;
transport and technological vibration, which occurs during the operation of machines performing a technological operation and moving along specially prepared surfaces of production premises, industrial sites, mine workings, etc. Sources of transport and technological vibration include excavators, cranes and construction machines, mining machines, mine reloading machines, track machines, concrete pavers, floor-mounted production vehicles;
technological vibration, affecting a person at workplaces of stationary machines or transmitted to other workplaces that do not have sources of vibration. Sources of technological vibration include: metal and woodworking machines, forging and pressing equipment, foundry and electrical machines, stationary electrical installations, pumping units and fans, machines for livestock farming, grain cleaning and sorting, equipment for the construction materials industry, installations in the chemical and petrochemical industries and etc.

The degree and nature of vibration on the human body depend on the type of vibration, its parameters and direction of impact.

General vibration affects the entire human body, local vibration affects individual parts of the body. However, this division of vibration is conditional, since local vibration ultimately affects the entire body. This is greatly facilitated by the good conductivity of mechanical vibrations by the tissues of the human body, especially bone tissue. Therefore, seemingly local vibrations in reality often spread to the most remote areas of the body surface and can reach significant amplitudes there.

The most common diseases are caused by local vibration.

Local vibration , which has a wide frequency spectrum, often with the presence of impacts (riveting, cutting, drilling), causes varying degrees of vascular, neuromuscular, osteoarticular and other disorders. Such vibration causes spasms of blood vessels, which, starting from the fingers, spread to the hand, forearm and cover the vessels of the heart, thereby disrupting the blood supply to the extremities. At the same time, local vibration affects nerve endings, muscle and bone tissue, which leads to a decrease in skin sensitivity, ossification of muscle tendons, and salt deposition in the joints of the fingers and hands, which leads to a decrease in their mobility. The so-called phenomenon of “dead” hands or white fingers is often observed. Under the influence of local vibration, disturbances in the activity of the central nervous system may occur.

They are very dangerous job fluctuations having a frequency resonant with the vibrations of individual organs or parts of the human body. For most internal organs, the natural frequencies of oscillations lie in the region of (6-9) Hz. For a person standing on a vibrating surface there are 2 resonant peaks at frequencies (5-12) Hz and (17-25) Hz, for a person sitting - at frequencies (4-6) Hz.

With systematic exposure to humans general vibration Persistent disorders of the musculoskeletal system and nervous system may occur, leading to changes in the cardiovascular system, vestibular system, and metabolic disorders. Such effects manifest themselves in the form of headaches, dizziness, poor sleep, fatigue and decreased performance, etc.

Long-term exposure to vibration may lead to the development vibration disease accompanied by persistent pathological disorders in the worker’s body. Successful treatment of vibration disease is possible only in the early stages of development. Severe forms of the disease, as a rule, lead to partial or complete loss of ability to work.

The occurrence of diseases is facilitated by such accompanying factors as cooling, large static muscle efforts, and industrial noise. When working with pneumatic hand-held machines, the hands are cooled by exhaust air and the cold metal of the machine body. In some cases, due to the significant mass of a manual machine, a worker makes efforts to hold and operate this machine.

Vibration protection provided:

a system of technical, technological and organizational solutions and measures to create machines and equipment with low vibration activity;
a system of design and technological solutions for production processes and elements of the production environment that reduce the vibration load on the worker;
a system of labor organization and preventive measures that weaken the adverse effects of vibration on humans.

The most effective means of protecting a person from vibrations is to eliminate direct contact with vibrating equipment. This is done through the use of remote control, industrial robots, automation and replacement of technological operations.

A radical means of providing vibration safety is the creation and use of vibration-proof machines.

At the enterprise vibration safety provided:

compliance with the rules and conditions of operation of machines and the conduct of technological processes, use of machines only in accordance with their purpose, provided for by regulatory and technical documentation;
maintaining the technical condition of machines, parameters of technological processes and elements of the production environment at the level provided for by regulatory and technical documentation, as well as timely implementation of scheduled preventive maintenance;
improving the operating modes of machines and elements of the production environment, eliminating contact of workers with vibrating surfaces;
introduction and observance of work and rest regimes that best reduce the adverse effects of vibration on humans;
implementation of sanitary, preventive and health measures;
use of personal vibration protection equipment.

The radical direction of the fight against vibration(as well as with noise) is the elimination of noisy and vibration-hazardous technological processes (replacing riveting with welding, stamping with pressing, etc.).

When designing technological processes and industrial buildings and structures, machines with the lowest parameter values should be selected vibration characteristics , workplaces (zones) where workers may be exposed to vibration have been recorded, machine layouts have been developed taking into account the creation of minimum levels of vibration at workplaces, construction solutions for foundations and floors for installing machines have been selected, ensuring hygienic vibration standards at workplaces, etc. P.

To avoid contact of workers with vibrating surfaces outside the workplace (zone), it is necessary to mark out dangerous (from the point of view of vibration) areas with fences, warning signs, inscriptions, painting, etc.

Vibration reduction machines is achieved by carefully balancing rotating parts, reducing dynamic processes caused by impacts, sudden accelerations, etc.

Application vibration damping – conversion of the energy of mechanical vibrations of the system into other types of energy (for example, thermal) also helps to increase vibration safety.

Vibration isolationis carried out by introducing additional elastic connections into the system that prevent the transmission of vibration from the machine to the base or other structural elements.

It is recommended that the total contact time of the worker with vibrating machines , the vibration of which corresponds to acceptable levels, did not exceed 2/3 of the working day, and the continuous duration of exposure to vibration, including micro-pauses, was (15-20) min. It is also recommended to establish two regulated breaks for active recreation, physioprophylactic procedures, and industrial gymnastics according to a special complex.

In connection with the above, it is not permitted to carry out overtime work with vibrating machines . It is advisable to create integrated teams working on the principle of interchangeability and combination of professions, which makes it possible to ensure the uninterrupted operation of mechanisms, as well as providing regulated breaks to workers based on occupational health requirements.

For vibration protection Personal protective equipment is used for the operator’s hands, feet and body. As a means of protection for hands, mittens and gloves, liners and gaskets are used. GOST 12.4.002 "System of occupational safety standards. Hand protection against vibration. Technical requirements and test methods" .

Vibration-proof footwear is made in the form of boots, ankle boots, the bottom of which uses elastic-damping material ( GOST 12.4.024 "System of occupational safety standards. Special vibration-proof footwear. General technical requirements" ).

Personal protective equipment for the body According to the form of execution, they are divided into bibs, belts, and special suits, which are also made from elastic-deforming materials.

Considering that the action vibrations aggravated by low temperatures, personal protective equipment must have insulating elements, and special heated rooms must be provided for warming workers.