Protective measures against mechanical injuries

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1. Adopt intrinsically safe technologies: (1) Avoid sharp edges, points, and protrusions. Without compromising their intended functions, mechanical equipment and their components should, as much as possible, be designed to avoid having sharp edges, points, rough or uneven surfaces, as well as protruding parts that could cause damage. The edges of the metal sheets should be rounded, folded, or smoothed, and the open ends that could cause scratches should be covered. (2) The principle of safety distance. Using a safety distance to prevent human contact with hazardous parts or entry into dangerous areas is a method to reduce or eliminate mechanical risks. When determining the safe distance, it is necessary to take into account various conditions that may arise during machine operation, measurement data related to the human body, as well as technical and practical factors. (3) Limit the physical quantities of relevant factors. Without affecting the functional capabilities, certain physical values that may pose a risk are restricted based on the distinct characteristics of various machines, in order to reduce such risks. For example, limit the operating force to its minimum value so that the control element does not pose a mechanical hazard due to damage ； Limit the mass or speed of the moving part in order to reduce its kinetic energy ； Limit noise and vibration, etc. (4) Use intrinsically safe process systems and power sources. For machines intended for use in **environments, fully pneumatic or fully hydraulic control systems and actuation mechanisms should be employed, or \"intrinsically safe\" electrical devices may be used. Power supplies with a voltage lower than the \"ultra-low functional voltage\" can also be utilized, and flame-retardant and non-toxic liquids should be used in the machine’s hydraulic systems. 2. Limiting mechanical stress: The performance data of the materials used in machinery, as well as the design guidelines, calculation methods, and testing rules, must all comply with the professional standards or specifications for machinery design and manufacturing. This ensures that the mechanical stress on the components does not exceed acceptable levels, thereby maintaining a safety factor and preventing damage or failure due to excessive stress on the components, and avoiding malfunctions or accidents ； At the same time, stress is limited by controlling the connection, stress, and motion states. 3. Safety of materials and substances: The materials, fuels, and processing materials used in manufacturing machines must not pose a threat to the safety or health of people who are exposed to them during use. 4. Implementing safety ergonomics principles in mechanical design involves applying these principles through aspects such as the rational allocation of human and machine functions, adaptation to human characteristics, human-machine interface design, and the arrangement of the working space. This enhances the operational performance and reliability of the machinery, reduces the physical strain and psychological stress on operators to the minimum, and thereby minimizes operational errors. 5. Safety principles for designing control systems. Typical dangerous conditions during the operation of machinery include accidental startup, uncontrolled changes in speed, inability to stop movement, projection of moving machine parts or workpieces, and failure of safety devices to function properly. The design of control systems should take into account the operating modes of various tasks or employ fault indication devices to enable operators to intervene safely, following the following principles and methods: (1) The methods for initiating the mechanism and changing its speed. The initiation or acceleration of the mechanism should be achieved by applying or increasing voltage or fluid pressure; if binary logic elements are used, it should be accomplished by transitioning from the “0” state to the “1” state ； Conversely, shutdown or reduction in speed should be achieved by removing or reducing the voltage or fluid pressure; if binary logic elements are used, it should be accomplished by changing from a “1” state to a “0” state. (2) Principle of restart. When power is reconnected after a disruption, if the machine starts up on its own, it can be dangerous; therefore, measures should be taken to ensure that the machine does not start automatically upon power restoration, and it can only operate when the start button is pressed again. (3) Reliability of components. This should serve as the foundation for the completeness of safety functions; the components used must be able to withstand various disturbances and stresses under the intended operating conditions, so as to prevent dangerous malfunctions of the machine due to failures. (4) Directed failure mode. This means that the primary failure modes of a component or system are known in advance, and since it is always these components or systems that fail, appropriate preventive measures can be taken in advance against their failure modes. (5) Doubling (or redundancy) of critical components. The key components of a control system can be backed up, meaning that if a component fails, a backup component can take its place to ensure the desired function is maintained. When combined with automatic monitoring, the automatic monitoring system should employ different design techniques to avoid common cause failures. (6) Automatic monitoring. The function of automatic monitoring is to ensure that, when the ability of a component or element to perform its functions declines or when dangerous situations arise due to changes in processing conditions, the following safety measures are activated: stopping the dangerous process, preventing automatic restart after a fault-induced shutdown, and triggering alarms. (7) Protection of safety functions in reprogrammable control systems. In critical security control systems, it is necessary to take reliable measures to prevent stored programs from being altered intentionally or unintentionally. If possible, a fault detection system should be used to check for errors caused by changes to the program. 6. Safety protection measures: Safety protection refers to safety technical measures that involve the use of safety devices, protective gear, or other means to prevent various mechanical hazards; its purpose is to avoid any harm to people that may occur as a result of the machine’s operation. Protective devices and safety devices are sometimes collectively referred to as safety protection devices. The focus of safety protection lies in the mechanical transmission parts, the operation area, the areas where work is carried out at heights, other moving parts of the machinery, the areas within which mobile machinery moves, as well as special protective measures required for certain machines due to their specific types of hazards. The means of protection to be adopted should be determined based on the results of a risk assessment of the specific machine. Safety protection devices must meet the safety technical requirements appropriate to their protective functions, and their basic safety requirements are as follows: (1) The structure and layout design should be reasonable, providing effective protection to ensure that human bodies are not harmed. (2) The structure should be strong and durable, resistant to damage ； It has a reliable installation and is not easy to remove. (3) The surface of the device shall be smooth, free of sharp edges or corners, shall not introduce any additional hazards, and shall not become a new source of danger. (4) The device should not be easily bypassed or avoided, and there should be no unprotected areas. (5) Meet the requirements for safety distance to prevent various parts of the body (especially hands or feet) from coming into contact with hazards. (6) It must not affect normal operation, and must not come into contact with any movable parts of the machinery ； It causes the least disruption to a person’s line of sight. (7) Easy to inspect and repair.