The safety function of machinery means that some functions of machinery and its parts are specially designed to ensure safety, which are mainly divided into two categories: main safety function and auxiliary safety function. The following is a complete collection of mechanical safety technical knowledge I have compiled for you. Welcome to read and browse.
The first section machinery industry safety overview
Knowledge point 1. Main categories of mechanical products
1, the main products of machinery industry include 12:
2, focus on understanding (2) heavy mining machinery; (4) General machinery for petrochemical industry.
3. Non-mechanical industries include railway machinery, construction machinery, textile machinery, light industrial machinery and marine machinery.
Knowledge point 2. Dangerous parts of mechanical equipment and protective countermeasures
(1) Dangerous parts of machinery and equipment
1, mechanical equipment will cause collision, attack, shear, involvement and other injuries.
2. Between rotating parts, connectors and moving parts; Proximity type; Pass type; Unidirectional sliding
(2) Safety protection measures for mechanical transmission mechanism
1. Common transmission mechanisms on machine tools include gear meshing mechanism, belt transmission mechanism, coupling, etc. Dangerous parts of the transmission mechanism must be protected.
2. Generally speaking, the safety technical measures taken can be divided into three categories: direct (design time), indirect (protective devices) and guided (safety regulations and signs).
3. Key points: safety protection of gear transmission: the gear transmission mechanism must be equipped with a fully enclosed protective device, and it cannot be used without a protective cover; The protective cover of the belt transmission device can use the protective net of metal skeleton, and the distance from the belt should not be less than 50mm, so as not to affect the operation of the machine. General transmission mechanism below 2 m from the ground, should set up a protective cover. Protect three situations: pulley spacing is greater than 3 m; Belt width is above 15 cm; Belt rotation speed is above 9 m/min; What is the most common protection of coupling? T-shaped protective cover.
Knowledge point three. Types of Mechanical Injuries and Preventive Measures
(1) Types of mechanical injuries
1. Mechanical state: normal working state, abnormal working state and non-working state.
2. The machinery industry includes mechanical injuries and non-mechanical hazards.
3. Main dangers and hazards: 65,438+04 kinds, such as object strike, vehicle injury, mechanical injury, lifting injury, electric shock, burn, fire, falling from a height, etc.
(2) Preventive measures for mechanical injuries: sequence
1, realizing mechanical intrinsic safety: ① eliminating the causes of danger. (2) reduce or eliminate the number of contact with dangerous parts of the machine; (3) make it difficult for people to get close to the dangerous parts of the machine (or provide safety devices so that getting close to these parts will not cause harm); (4) Provide protective devices or protective clothing.
2. Protect the safety of operators and related personnel: ① Improve people's ability to distinguish dangers through training; ② Redesign the machine to make the danger more obvious (or use warning signs); ③ Improve the ability to avoid injury through training; ④ Awareness of taking necessary measures to avoid injury.
(3) Technical requirements for general mechanical safety facilities
1, general requirements for mechanical safety protection devices. The safety protection device is reliable and interlocked with the equipment operation.
2. Key points: Emergency stop switch. The emergency stop switch shall ensure that all movements of the equipment can be terminated during the instantaneous action. For the equipment with inertia movement, the emergency stop switch should be interlocked with the brake or clutch to ensure the quick termination of operation. The shape of the emergency stop switch should be different from the general switch, and the color is red; The arrangement of the emergency stop switch shall ensure that the operator can easily reach it without causing danger; After the equipment is stopped by the emergency stop switch, it must be restarted in the starting order before it can be restarted.
3. When the protective cover is used as a platform or ladder, it should be able to bear the vertical force of1500 n..
Knowledge point four, mechanical safety design and machine safety device
(1) Intrinsic safety: It is a mechanical safety method that mechanical designers take measures to eliminate hidden dangers at the design stage.
(2) Failure safety: The designer should ensure that there is no danger when the machine fails.
(3) Positioning safety: Put the parts of the machine out of reach and achieve safety through positioning.
(4) Machine layout: space, lighting, pipeline layout and channel safety during maintenance.
(5) Machine safety protection device
Focus on: interlocking, control and two-hand control safety devices.
Five, mechanical manufacturing site safety technical knowledge
(1) Daylighting: When the span of the workshop is greater than 12 m, there should be daylighting side windows on both sides of the single-span workshop, and the window width should not be less than 1/2 bay length; Multi-span factories are connected, and each connected span should have a skylight, and there should be no wall between spans. The lighting of workshop passages shall cover all passages, and the coverage length shall be greater than 90% of the length of workshop safety passages.
(2) Access: including the main roads in the factory and the safe access in the workshop.
1. Paving requirements for main roads in the plant area: the width of main roads with two-way traffic is not less than 5m, and the width of main roads with one-way traffic signs is not less than 3m; When entering the factory gate, speed limit signs, signs and warning signs should be set up in dangerous areas.
2, workshop safety channel requirements. Passing vehicles, width >; 3m； Battery car width >1.8m; Width of trolleys and tricycles >1.5m; General pedestrian passage width >; I am.
(3) Equipment layout: length > 12 m is large equipment, and 6 ~ 12m is medium equipment.
(4) Material stacking
1, including the placement of workstation equipment, workpieces and materials.
2. Storage capacity of product blanks: the product blanks should be stored in limited quantities, with the storage capacity of 65438+ 0.5 times of the processing capacity of each shift and 2.5 times of the processing capacity of night shift, but the large pieces should not exceed the duty quota.
3. Workpieces and materials shall not be placed at an ultra-high level. On the premise that the ratio of the bottom of the stack to the stack height is 1: 2, the stack height shall not exceed 2m (except ultra-high units), and the stacking of sand boxes shall not exceed 3.5m..
(5) Ground conditions: The production site is required to be flat and clean. Pits, ditches and pools with a depth of more than 0.2 m and a width of more than 0. 1 m should have reliable protective fences or covers.
Section 2 Safety Technology of Metal Cutting Machine Tools and Grinders
Knowledge point 1. Risk factors of metal cutting machine tools
Static parts, rotating parts, internal rotating bite, reciprocating motion and sliding hazards, flying objects.
Knowledge point 2. Safety technical measures for metal cutting machine tools
1. Abnormal state of machine tool operation: 1) Abnormal temperature rise 2) Abnormal speed 3) Excessive vibration and noise 4) Impact sound 5) Abnormal input and output parameters 6) Internal defects of machine tool.
The failure rate of vibration is the largest: machine tool failures caused by vibration account for 60%~70% of all failures.
2. Fault detection of wearing parts of sports machinery.
Key points: Wearable parts include transmission shaft, bearing, gear and impeller, among which the damage of rolling bearing and gear is more common.
3. Control measures for common risk factors of metal cutting machine tools: 1) The equipment is reliably grounded, and safe voltage is used for lighting. 2) Wedges and pins shall not protrude from the surface. 3) Use special tools and goggles. 4) Tail safety bending device and material rack. 5) The parts are firmly clamped. 6) Maintain safety protection and protection devices in time. 7) Select qualified grinding wheels and install them reasonably.
(8) Strengthen inspection, put an end to violations, and wear labor protection articles.
Knowledge point three. Safety technical requirements for grinding machines
Installation of grinder: location selection. The front of the grinder is equipped with a protective baffle, the height of which is not less than1.8m.
Balance of grinding wheel. Grinding wheels with a diameter greater than or equal to 200mm shall be statically balanced and debugged after flange installation.
Matching between grinding wheel and chuck. The flange diameter of grinding wheel shall not be less than 1/3 of the installed grinding wheel diameter, and it is stipulated that when the grinding wheel diameter is worn to be larger than the flange diameter 10mm, a new grinding wheel shall be replaced.
Protective cover of grinding machine. The opening angle above the horizontal plane of the spindle is not allowed to exceed 65 ". When the opening is greater than or equal to 30 ",a chip screen must be set, and the gap between the circumferential surface of the grinding wheel and the baffle should be less than 6mm.
Workpiece support of grinder. When the diameter is above 150m, an adjustable bracket must be installed, and the distance between the grinding wheel and the bracket should be less than 1/2 of the minimum size of the workpiece to be ground, but the maximum should not exceed 3 mm..
Safety requirements for using grinder: side grinding is prohibited; No frontal surgery; There is no * * * operation.
Section 3 Safety Technology of Stamping (Shearing) Machinery
Knowledge point 1. Risk factors of stamping operation
Danger of equipment structure; Out of control; Switch failure; Risk of mold (the injured part is mainly the hand).
Knowledge point 2. Safety technical measures for stamping operation
Including improving stamping operation mode, reforming die structure, realizing mechanization and automation, and setting protective devices for dies and equipment. The mechanization and automation of stamping operation is the fundamental measure to reduce the labor intensity of workers and ensure personal safety.
Key points: safety device of stamping equipment. According to the structure, it can be divided into mechanical type, button type, photoelectric type and induction type. Mechanical protection device. There are mainly: hand-push type, swing rod type (hand-pull type) and handle type safety devices.
Knowledge point three. Safety technical measures of plate shearing machine
Matters needing attention in the operation of shearing machine (points 2, 4 and 5). Don't operate the shearing machine alone 1 person; Protective covers must be installed on moving parts; The operator's fingers should be kept at a safe distance, and the fingers should be at least 200mm away from the scissors mouth and away from the pressing device.
The fourth quarter woodworking machinery safety technology
Knowledge point 1. Dangerous and harmful factors of woodworking machinery
High spindle speed, multi-cutter, multi-blade, manual feed, etc. Mechanical injury: high risk and high probability of occurrence; Fire and explosion: serious consequences; Biological and chemical hazards of wood; Sawdust hazard; Noise and vibration hazards.
Knowledge point 2. Safety technical measures of woodworking machinery
1, woodworking machinery should be equipped with perfect safety devices in design, including safety protection devices, safety control devices and safety alarm signal devices. Unarmed operators must have safety protection measures, such as noise elimination, dust absorption or ventilation devices, safety combined control devices for cutter shafts and electricity, safety feeding devices or safety screen protectors for isolating cutters and preventing rebound, and safety control devices for emergency stop in case of accidents.
2. Hand planing is a frequent accident, and the design and installation requirements of hand planing cutter shaft: 1) Cylindrical cutter shaft must be used, and square cutter shaft is absolutely forbidden. 2) The outer edge of the pressure blade should match the excircle of the cutter shaft. When the hand touches the knife shaft, it will only hurt the skin of the finger and will not be cut off. 3) The extension of the planer should not exceed the outside diameter of the cutter shaft 1. 1 mm ... 4) The opening of the planer should comply with the regulations.
Section 5 Casting Safety Technology
Knowledge point 1. Dangerous and harmful factors in casting operation
Fire and explosion, combustion, mechanical injury, falling from a height, dust and toxic hazards, noise and vibration, high temperature and thermal radiation.
Knowledge point 2. Safety technical measures in casting operation
(1) process requirements
Wet operation should be adopted when the process is possible, and remote control and isolation operation of manipulator should be adopted when the operating conditions are poor. The molding core-making section with less pollution should be arranged on the downwind side of the minimum frequency wind direction in non-heating season in central heating area and on the downwind side of the overall minimum frequency wind direction in non-central heating area.
(2) Building requirements: The foundry workshop should be arranged in the buildings of high-temperature workshop and power workshop, and built on the downwind side of other production buildings that do not release harmful substances; The workshop mainly faces the appropriate north-south direction; Green belt.
(3) Dust removal: The flue gas purification equipment of electric arc furnace should adopt dry high-efficiency dust collector; Cupola smoke purification should adopt mechanical smoke purification equipment.
Section 6 Forging Safety Technology
Knowledge point 1. Characteristics of forging
When the metal is hot, the equipment used, such as air hammer, steam hammer, friction press and so on. , all send out the impact force, the force is very big.
Knowledge point 2. Dangerous and harmful factors of forging
Injury accidents: mechanical injury, fire, explosion and burning (800~ 1200).
Occupational hazards: noise and vibration, dust and toxic hazards, thermal radiation.
Knowledge point three. Forging safety technical measures
12 points (master key starting devices 3, 4 and 5 and 1 1). Exposed transmission device (gear transmission, friction transmission, crank transmission or belt transmission, etc. ) must have a protective cover; The starting device must be able to ensure that the equipment can be quickly switched on and off, and ensure the continuous and reliable operation and parking status of the equipment; The button box of electric starting device should be marked with? Start? 、? Stop the car and wait. The stop button is red, higher than the start button 10. 12mm; Newly installed and overhauled forging equipment shall be accepted and tested according to equipment drawings and technical specifications.
Section 7 Basic knowledge of safety ergonomics
Knowledge point 1. Definition and research content
( 1)? People? Machine? Environment? system
The fundamental requirement to solve the safety problem is to realize the mechanization and automation of the production process.
(2) Types of man-machine systems: there are two main types, one is mechanized and semi-mechanized controlled man-machine systems; The other is a fully automatic man-machine system.
1) Mechanized and semi-mechanized man-machine system: People mainly act as operators and controllers in the production process. The safety of the system mainly depends on the rationality of man-machine function distribution, the intrinsic safety of the machine and the situation of human error.
2) Fully automatic man-machine system: people are monitors and managers. The safety of the system mainly depends on the intrinsic safety of the machine, the failure of the redundant system of the machine and the poor emergency response of people at low load.
Section 8 Human characteristics
Knowledge point one, anthropometry
(1) static measurement.
Measurement method: Different postures can be adopted, including standing posture, sitting posture, kneeling posture and lying posture.
Anthropometric data refers to the dimensions of different parts of the human body, which will be involved in the design of different equipment or products.
Factors affecting anthropometric data: race, sex, age and occupation.
(2) Dynamic measurement
(3) Application guide of anthropometric data
Maximum and minimum standards, adjustability standards, average standards, standards for using the latest human body data, regional standards, and standards for combining functional correction with minimum psychological space (clothing correction amount, functional correction amount for obtaining the minimum functional size, and additional psychological correction amount for obtaining the best functional size).
Knowledge point 2. Physiological characteristics of human beings
1, visual
Dark adaptation and light adaptation: the transition time of dark adaptation is long, it takes about 30min to adapt to light, and it takes about1min;
Hazards of glare: dark adaptation is destroyed, resulting in visual afterimages; Reduce the illumination to the retina; Weaken the contrast between the observed object and the background; When observing an object, it will produce a sense of fuzziness, which will affect the normal operation of the operator.
Optical illusion: shape illusion, color illusion, object motion illusion. Common shape illusions include length illusion, direction illusion, contrast illusion, size illusion, distance illusion and perspective illusion. Color illusion includes contrast illusion, size illusion, temperature illusion, distance illusion and fatigue illusion.
Visual damage and visual fatigue: The maximum brightness of visible light that the eyes can bear is about 106cd/m2. Short-wave ultraviolet below 300m can cause ultraviolet ophthalmia. After 4 ~ 5 hours of ultraviolet irradiation, the eyes will be congested, and after 10 ~ 12 hours, the eyes will be painful and you can't open your eyes. Frequent exposure to infrared rays can lead to cataracts. Looking directly at high-brightness light sources, such as laser and sunlight, will cause macular burns and may cause irreparable vision loss. Low illumination or low quality light environment will cause refractive defects or premature presbyopia of various eyes. Strong light or light with drastic and frequent illumination changes will lead to decreased visual function.
Law of visual movement: when people look at a target, the shortest staring time is 0.07~0.3s to obtain visual impression, which is related to the brightness of lighting. The average pause time of human vision needs 0. 17s.
2. Listening. The function of hearing is to distinguish the level and strength of sound, and also to judge the direction and distance of sound source in the environment.
Absolute thresholds of hearing: frequency threshold, sound pressure threshold and sound intensity threshold.
Auditory discrimination threshold: the human ear has the ability to distinguish sounds with different frequencies and intensities.
The ability to distinguish the direction and distance of sound.
3. People's feelings and reactions
Reaction time: it is the total time from reaction time including feeling to action. Under normal circumstances, the reaction time is about 0. 1-0.5S, for complex selective reaction time is 1-3S, and for complex judgment and understanding, the average reaction time is 3-5S.
Ways to reduce reaction time: 1) Choose the type of perception reasonably (the shortest auditory reaction time is 0.1-0.2s); 2) Design the machine according to the principle of ergonomics; 3) Improve people's reaction speed through training.
(2) Human body characteristic parameters
Parameters related to product design and machine operation: static parameters, dynamic parameters, physiological parameters and biomechanical parameters.
Parameters of human labor intensity: oxygen consumption, heart rate and human labor intensity. According to the labor intensity index I, physical labor intensity is divided into four levels: light physical labor, medium intensity labor, heavy intensity labor and heavy physical labor.
(3) Fatigue
Definition of fatigue: Fatigue can be divided into muscle fatigue (or physical fatigue) and mental fatigue (or mental fatigue).
Methods to eliminate fatigue: fully consider human physiological and psychological factors when designing; Improve the working environment; Reasonable arrangement of work and rest time.
3. Fatigue measurement methods: subjective feeling questionnaire, EEG analysis, stroboscopic value measurement, intelligence test, mental test, and continuous shooting of human movement changes.
4, monotonous work and shift work
Measures to avoid monotonous homework: cultivating generalists, extending work, redesigning homework, showing the ultimate goal of homework, reporting dynamic information, implementing recreational work methods and improving working environment.
Shift work: single shift, two shifts, three shifts or four shifts, etc. Many enterprises practice? Four shifts and three shifts? .
Knowledge point three. People's psychological characteristics
Ability: refers to a person's ability to complete a task. It mainly includes feeling, perception, observation, attention, memory, thinking imagination and operation ability.
The sum of various abilities constitutes human intelligence, including human cognitive ability and activity ability.
Emotions and emotions. Unsafe emotions include impatience and irritability.
Section 9 Mechanical characteristics
Knowledge point 1. Definition and characteristics of mechanical safety
Characteristics of mechanical safety. Modern mechanical safety has the characteristics of systematicness, protection, friendliness and integrity.
Knowledge point 2. Mechanical fault diagnosis technology
The basic process of fault diagnosis includes two parts: the establishment of diagnosis documents and the implementation of diagnosis. The basic steps of diagnosis implementation process: signal detection, feature extraction (or signal processing), state recognition and diagnosis decision.
(3) Fault diagnosis technology
1, detection and analysis of vibration signal
Vibration signals are usually measured by displacement, velocity or acceleration sensors. The sensor should be installed at the sensitive point of the diagnosis object or the key point closest to the core as far as possible.
2. Oil analysis technology: Spectral oil analysis and ferrography oil analysis are widely used.
3. Temperature detection and infrared monitoring technology.
4. Ultrasonic flaw detection technology: It can detect and inspect all solid materials.
5. Surface defect detection technologies: magnetic particle detection, penetrant detection and eddy current detection.
Knowledge point three. Reliability design and maintainability design of machinery
Definition of reliability: refers to the ability of a system or product to complete the specified functions under the specified conditions and within the specified time.
Reliability measurement indicators: reliability, failure rate (or failure rate), average life (or mean time between failures), maintenance degree and effectiveness.
Validity: narrow sense reliability r(t) and maintenance m (? ) is called validity, also called generalized reliability.
(2) Maintainability design
Maintainability refers to the difficulty of repairing faulty products. That is, the difficulty of completing a product maintenance task under the specified conditions and within the specified time.
The main issues to be considered are accessibility, standardization and interchangeability of components, and safety of maintenance personnel.
Section 10 Man-machine working environment
Knowledge point one, light environment
(A) the measurement of light
Concepts: luminous flux, luminous intensity (light intensity), brightness and illumination. Insufficient light is an important reason.
(B) the impact of lighting on the operation
Lighting and fatigue, lighting and accidents. Visual fatigue is the main cause of accidents and work efficiency.
Knowledge point 2, color environment
Characteristic color has three basic characteristics: hue, lightness and chroma.
Effect of color on physical and visual fatigue.
Knowledge point three. Microclimate environment
Microclimate elements: temperature, air humidity, wind speed and thermal radiation.
The temperature is divided into comfort temperature (2 1? 3℃) and allowable temperature (comfortable temperature? 3~5 ℃)。
Air humidity includes absolute humidity and relative humidity. The relative humidity is high when it is above 80%, and low when it is below 30%. The general comfortable humidity is 40%~60%.
The outdoor wind speed is generally 0. 15m/s, and the air is fresh.
(B) human feelings and microclimate environment evaluation
1, comprehensive evaluation of microclimate environment. 1) Effective temperature (sensible heat temperature): dry bulb temperature, wet bulb temperature, air velocity; 2) discomfort index: dry bulb temperature and wet bulb temperature; 3) Three-ball temperature index wbgt: dry ball, wet ball and black ball; 4) Catastrophe: temperature, humidity and wind speed.
2. Influence of high-temperature working environment on human body: High-temperature environment accelerates human heart rate and breathing, while hot and humid environment inhibits the central nervous system. In high temperature environment, human body loses a lot of water and salt.
3. Influence of low temperature environment on human body: The critical skin temperature of hand tactile sensitivity is about 10℃.
Section 11 Man-machine system
Knowledge point 1. Model of man-machine information and energy exchange system
Any activity of man-machine system is essentially the transmission and exchange of information and energy.
Knowledge point 2, man-machine function allocation
1. The main functions of human in man-machine system: perception function, information processing function and manipulation function.
2. The principle of man-machine function distribution: heavy, fast, durable, high reliability, high precision, regularity, monotonicity, high-priced operation, complicated operation and poor environmental conditions are suitable for machines; Research, creation, decision-making, arrangement of instructions and procedures, inspection, maintenance, fault handling and emergency handling are all suitable for people.
Knowledge point three. Reliability calculation of man-machine system
(A) the reliability calculation of man-machine system
1, man-machine series system. Man-machine parallel system: parallel work redundancy method and backup redundancy method.
2. Two people monitor the reliability of the man-machine system: when it is abnormal, it is equivalent to two people in parallel; Normal is equivalent to two people in series.
When the situation is abnormal, Rsr? =RHb？ RM =[ 1-( 1-r 1)( 1-R2)]RM
In general, Rsr? =RHc？ RM=Rl？ R2？ space
(2) Basic principles of reliability design of man-machine system.
1, principle of overall system reliability, principle of high reliability components, principle of design with safety factor, principle of high reliability mode, principle of standardization, principle of high maintainability (standardization of parts, generalization of parts, serialization of equipment), principle of early testing and evaluation, principle of prediction and prevention, principle of ergonomics, principle of technical economy, principle of reviewing, sorting and preparing data and exchanging information, principle of information feedback, principle of information exchange.
2. The principle of high reliability mode: redundant design, fail-safe device and automatic safety device.
3. There are the following types of fail-safe structures:
1 passive passive. When the assembly unit fails, the machine stops running.
② Proactive. When the component unit fails, the machine can give an alarm and run for a short time.
③ Type of operation. Even if the component unit fails, the machine can run until the next periodic inspection.
Usually in industrial systems, most of them are passive structures.
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