(1) Types of mechanical injuries There are two kinds of unsafe factors in the operation of mechanical equipment. One is mechanical hazards, including squeezing, rolling, shearing, cutting, winding or winding, or stabbing, rubbing or scratching, flying object impact, high-pressure fluid injection, collision or falling; The other is called non-mechanical hazards, including electrical hazards, noise hazards, vibration hazards, radiation hazards and temperature hazards.
In the machinery industry, there are the following main dangers and hazards:
(1) Object strike: refers to an accident in which an object moves under the action of gravity or other external forces and hits the human body, causing personal injury or death. It does not include attacks caused by major mechanical equipment, vehicles, lifting machinery and collapsed objects.
(2) Vehicle injury: refers to the casualty accidents caused by the falling of human body and the collapse, flying and squeezing of objects during the driving of motor vehicles in enterprises. It does not include accidents when lifting, towing vehicles and vehicles stop.
(3) Mechanical injury: refers to the injuries such as squeezing, collision, impact, shearing, winding, twisting, throwing, cutting, cutting and stabbing caused by the direct contact between moving (static) parts, tools and machined parts of mechanical equipment and human body. Does not include injuries caused by vehicles and lifting machinery.
(4) Lifting injury: refers to the injury caused by squeezing, falling and the impact of objects (slings and lifting weights) in various overweight operations (including crane installation, maintenance and testing).
(5) Electric shock: including electric shock of all kinds of equipment and facilities, electric shock during electrical work and lightning strike.
(6) Burn: refers to flame burn, high-temperature object burn, chemical burn (internal and external burns caused by acid, alkali, salt and organic matter) and physical burn (internal and external burns caused by light and radioactive substances). Electrical burns and burns caused by fire are not included.
(7) Fire injuries: including burns and deaths caused by fire.
(8) Falling from a height: refers to the injury accident caused by falling during working from a height. Electric shock and falling accidents are not included.
(9) Collapse: refers to an accident in which an object exceeds its own strength limit or its structural stability is destroyed under the action of external force or gravity, such as earth and stone collapse, scaffolding collapse, stacking collapse, building collapse, etc. It does not include mine roof caving and collapse caused by vehicles, lifting machinery and blasting.
(10) Powder explosion: refers to the explosion accidents of powder, explosives and their products during production, processing, transportation and storage.
(1 1) chemical explosion: refers to explosion accidents (including gas decomposition, injection, explosion, etc. ) combustible gas, dust, etc. Mix with air to form explosive mixture and contact with explosive objects.
(12) Physical explosion: including boiler explosion and container overpressure explosion.
(13) Poisoning asphyxia: including poisoning, anoxia asphyxia and toxic asphyxia.
(14) Other injuries: refer to injuries other than the above, such as falling, twisting, falling, rubbing, etc.
As far as mechanical parts are concerned, the factors that hurt people are:
(1) shape and surface properties; Cutting elements, sharp edges, sharp corners, rough or too smooth.
(2) Relative position: relative motion, the relative distance between motion and static object is small.
(3) Quality and stability: the potential energy of parts that may move under the action of gravity.
(4) Mass, velocity and acceleration: kinetic energy of parts in controllable or uncontrollable motion.
(5) Insufficient mechanical strength: parts are broken or collapsed.
(6) Potential energy of elastic element, potential energy of liquid or gas under pressure or vacuum.
Mechanical devices can be dangerous in any state;
(1) Normal working condition. Under the normal working condition that the machine completes the predetermined function, there are inevitable but necessary movement elements to perform the predetermined function, which may have harmful consequences. For example, the relative movement of a large number of parts, the operation of sharp tools, the noise and vibration of mechanical operation, etc. The collision, cutting, environmental deterioration and other dangerous factors of machinery are not conducive to personnel safety under normal working conditions.
(2) Abnormal working conditions. Abnormal working state refers to the unexpected state caused by various reasons in the process of mechanical operation, including fault state and maintenance state. Equipment failure will not only cause local or whole machine to stop running, but also cause danger to personnel. For example, the failure of the electrical switch may lead to the danger that the machine cannot stop; Damage to the grinding wheel blade will cause the grinding wheel to fly out and cause the object to hit; Failure of speed or pressure control system will lead to the danger of speed or pressure out of control. Mechanical maintenance is generally carried out in the shutdown state, but the particularity of its operation often forces maintenance personnel to take some unconventional measures, such as climbing, entering narrow or almost closed space, short circuit of safety devices, entering dangerous areas where normal operation is not allowed, etc. This makes the maintenance or repair process prone to dangers that do not exist in normal operation.
(3) non-working state. When the machine stops running and is in a static state, under normal circumstances, the machine is basically safe, but accidents, such as collision accidents caused by insufficient ambient light, are not excluded; Outdoor machinery slides or capsizes under the action of wind; Structural collapse, etc.
(II) Countermeasures to prevent mechanical injuries There are two countermeasures to prevent mechanical injuries.
1. Realizing mechanical safety:
(1) to eliminate the cause of the danger (see? Intrinsically safe? );
(2) Reduce or eliminate the demand for dangerous parts in contact with 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.
The above measures are given in order, and these measures can also be used in combination.
(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 Enhance the awareness of taking necessary measures to avoid injury.
(3) Technical requirements for general mechanical safety facilities 1 Factors to be considered in the setting, design and safety device of safety facilities.
When designing safety devices, human factors should be considered. Fatigue is an important factor leading to accidents. Designers should consider the following factors to minimize human fatigue.
(1) Arrange all kinds of control and operation devices correctly.
(2) Choose the position and height of the working platform correctly.
(3) provide seats.
(4) Convenient access to the job site.
When the design cannot achieve intrinsic safety, safety devices should be used to eliminate the danger. When setting safety devices, four factors should be considered:
(1) strength, rigidity and durability.
(2) The impact on the reliability of the machine, such as the strong safety device may overheat the machine.
(3) Visibility (from the point of view of operation and safety, it may be necessary for the dangerous parts of the machine to have good visibility).
(4) Control of other hazards, such as selecting special materials to control the total noise.
2. General requirements for mechanical safety protection devices
(1) The safety protection device shall be simple in structure and reasonable in layout, without sharp edges and flanges.
(2) The safety protection device shall have sufficient reliability, strength, rigidity, stability, corrosion resistance and fatigue resistance within the specified service life to ensure safety.
(3) The safety protection device should be interlocked with the operation of the equipment to ensure that the equipment cannot run before the safety protection device works; The materials of safety shields, screens and fences and their distance from running parts shall comply with the provisions of GB 8 1962003.
(4) Safety protection devices such as photoelectricity and induction should be equipped with fault alarm devices.
(5) 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.
(6) The shape of the emergency stop switch should be different from the general switch, and the color is red.
(7) The emergency stop switch shall be arranged to ensure that the operator can easily reach it without danger.
(8) After the equipment is stopped by the emergency stop switch, it must be restarted in the startup order before it can be restarted.
3. Technical requirements of mechanical equipment safety protection net
1) Technical Requirements for Safety Shield of Mechanical Equipment
(1) As long as the operator may touch the moving parts, the moving parts cannot be operated until the protective cover is closed.
(2) When using the fixed protective cover, the operator can't touch the moving parts in operation.
(3) There is enough clearance between the protective cover and the moving parts to avoid any contact between the protective cover and the moving parts.
(4) The protective cover shall be firmly fixed on the equipment or foundation, and tools must be used for disassembly and adjustment.
(5) When the open protective cover is opened or partially fails, the moving parts shall be prevented from running or stopped.
(6) The protective cover used is not allowed to bring new danger to the production site.
(7) Does not affect the operation. There is no need to remove the protective cover during normal operation or maintenance.
(8) The protective cover must be solid and reliable, so as to avoid damage to moving parts and injuries caused by workpiece flying out.
(9) general protective cover is not allowed to trample and stand; When a platform or ladder must be made, it should be able to bear the vertical force of 1500N, and anti-skid measures should be taken.