Weak current College】 【professional stage machinery safety design parameters.

<br> <br> First, an overview <br> Stage machinery one of the most important indicator is the safe, reliable, and all kinds of stage machinery must be guaranteed at all times is absolutely secure. <br> On the stage machinery .reliability design, very few of the present study. Reliability design theory is built on a large number of experimental data, on the basis of different applications require different reliability, equipment reliability is based on its important, work requirements and ease of maintenance, and other .factors into consideration. The stage machinery of the usage is not high, load rate is low, the life design a set of requirements and design for reliability is very high, because in the event of a problem may result in serious accidents or large economic losses .. Stage machinery must have a high reliability, failure probability should be 0.1 ~ 1.0%. Due to the lack of the necessary experimental data and specific in-depth research, reliability and design theory at the stage of mechanical design, there is no specific application .. Research shows that although only safety factor does not completely reflect the reliability level, but on the stage in the design of the mechanical components of the arguments as random variables, there is a lack of adequate data. Therefore, the design parameters used for determining .the amount of stress intensity factor of perhaps as a differentiator, by selecting the appropriate safety factors to approximate control its reliability, remains the current stage machinery design-led approach. As a result of calculation results and the actual situation has some deviations, it must .be made to compute the allowed parts of bearing capacity necessary for the safety margin, this is the starting point for determining the basic safety factor. Typically, the stage machinery should also propose design life indicators. The length of life of indicators on the stage machinery .does not apply to work hours in the life of the more realistic, 8000 ~ 10000 hours of working life should be the basis for the stage machinery design. <br> The stage machinery of security indicators including device security, physical security and electrical safety aspects ., and that these three factors associated with each other, mutual influence, sometimes are inseparable. <br> 2. safety equipment <br> Device security refers to the stage machinery equipment in working condition long-term use no accident; in the event of .a temporary failure could reduce the technical parameters after working capacity; stage machinery equipment on non-functional State of perception, ability to display and alarm. This capability or performance are usually mechanical design itself and completed with electric control; consider performance stage machinery cannot be .ruled out as soon as possible of a temporary failure of the stage machinery of the failure as possible without affecting the performance of the work. <br> Involves device security to a number of factors, mainly has following several aspects: <br> 1. .adequate factor of safety <br> All mechanical parts of the selection and design must guarantee at rated load and inertia loads under the combined action, be reliable and have certain security reserve, ie sufficient safety factor. Safety factor is defined as: all the materials .of the ultimate stress and part of the maximum operating stress ratio. Part of the working conditions should consider maximum static load and dynamic load (emergency braking, collision, and so on reboot inertial load) under stress. For example: hanging weights or traction wire .rope, the safety coefficient should be greater than or equal to 10; lifting chain of safety should be greater than or equal to 12; transmission chain of safety should be greater than or equal to 10; all parts of the transmission system in the selection should .be able to withstand two times the load rating; initial brief calculations, transmission parts and mechanical parts of the safety coefficient should be greater than or equal to 6, precise calculation of the safety coefficient should be consistent with the relevant standards or specifications on the part .of the class. <br> 2. appropriate stiffness <br> The stage machinery of major force widget should have appropriate stiffness in order to adapt to the needs of the stage performance. Typically, the provisions in force in the Member deflection should be less .than the widget span of 1 / 1000 ~ 1 / 800, sometimes also the absolute value of the deflection, these components must meet both requirements. Transmission parts of torsional rigidity, stability, etc. compressed should comply with the standard norms. On the platform ., in order to obtain sufficient lateral rigidity, which calculates the horizontal load of not less than the vertical movement of the load of 1 / 20. <br> 3. reasonable structure and the dimensional parameters <br> To avoid or reduce certain structural dimensions .of machine parts as unreasonable and excessive additional stress or premature fatigue failure, the design-time structure should be given enough attention. Winch system parts typical, such as: winch drive drum diameter should be greater than the diameter of the wire rope and pulley diameter .18 times larger than the diameter of the wire rope 20 times, friction drive (traction transmission) of the driving wheel diameter should be greater than 40 times the diameter of the wire rope, etc., all of the accessories are ropes and wire rope diameter .to be matched, rope connector can only use those delivery loads greater than 80% of the wire rope breaking load of the coupling type, such as: splicing connector, alloy cast casing joints, wedge-shaped connectors, extruded aluminium alloy casing and comply with .the requirements and proper use of steel wire rope clips, etc. Drum flange height should be greater than 2 times the diameter of the wire rope, single-layer winding of the drum, leaving at least two ring friction fixed ring, steel rope and reel .or pulley of deflection angle should be less than 4 °. <br> 4. reliable security appliance <br> The stage machinery and equipment must have better security protection devices to ensure the safety of the operation of equipment. General devices are equipped with stroke .limit switches and hyper-limit switch. Similar to the boom winch or supposes, winch rope protection, job hopping or composite rope protection, overload protection and speed (over current) protection and other security measures and in the very context display and alarm in the .event of a dangerous situation, the control system only allows devices to reduce the risk of direction of movement. When the device returns to normal status in order to continue the original campaign. For security purposes, the stage machinery of the brake must be: two .independently controlled brakes (or hydraulic lock), or institutions self-locking (including reducer self-locking) together with a brake. Moreover, each actuator is take all the transmission torque. In a two-stage brake when one is working brakes, another .is the safety brake. <br> 5. the necessary spare system or device <br> Equipment incidental result of a fault, to have the necessary measuresShi can continue to use (or in reducing technical parameters continue to use) equipment, or can make .the device returns to a secure location. These measures include: auxiliary transmission system (electric or manual), multipoint transmission system, the computer control system and its components in a redundant configuration. The device comes with secondary transmission system commonly used in music pool lifts ., main lifts, and multiple identical equipment auxiliary transmission systems, such as the boom winch room for boom winch of secondary transmission system, often is independent. Multipoint transmission system for alternate in the turntable, auxiliary lift and self-propelled vehicle platform more applications. .In the computer control system, a number of important, more components such as the frequency use redundant configuration. <br> 6. the provisions relating to the design data and <br> Due to the particularities of the stage machinery, foreign standards often design .data for specific or different from the provisions of the General machinery. Although there is no specific internal design standards, but in recent years an increasing number of international exchanges, these provisions have also been domestic recognition stage machinery design units. These requirements are: < .br> 1) load: static load drawer unit with fixed table of static load is the same as for large and medium-sized Theatre 5000N/m2, the audience of load moving equipment are: <br> Lifts: 2500N/m2 (single platen .or double-bed power Board) <br> 1500N/m2 (double-layer bed down plate) <br> Train station: 2500N/m2 <br> Turntable (with car turntable): 2500N/m2 <br> Music pool lifts: .2500N/m2 <br> Various secondary weight lifting table: <br> Bench equipment loads according to actual needs determine, no specific provisions on major equipment such as boom winch, track point crane, free single point lifters abroad are shaping product for design selection .. <br> 2) transmission device <br> Transmission (including the motor, gearbox, drive shaft coupling, etc) for calculation of bearing capacity should be the actual loading (or load rating) twice, the actual load is run in maximum load .. <br> 3) additional stroke <br> Under normal circumstances, the stage machinery of the total trip should include normal travel (by trip terminates switch control), hyper-journey (from the overtravel switch control) and extra trips. Additional travel .means the overtravel switching action, before the stage machinery stop walk distance. Additional travel and machine speed and inertia, in General, the speed is less than 0.1m / s, extra travel 0.07m is sufficient. Speed is less than 0.02m / s .hydraulic transmission, hydraulic cylinder with cushioning design, no extra trips. Balancing weight of extra stroke must ensure balanced weight and the supporting structure. <br> 4) positioning and locking <br> Under device must be able to prevent inadvertent movement of the lifting .device any possibility, wire, chain as bearing parts and hydraulic cylinder straight top without hydraulic lock or piston clamping device of the structure, you must set positioning locking device to ensure that the lift into the rest doesn't load after long-term effect and .sinking. <br> 5) brake <br> Each brake should be able to withstand all loads, brake braking force is accessible only by gravity or a spring force generation, with brake can be used for manual installations. <br> 6) balance .weight <br> Do not allow using spring instead of balance weight, balance weight should be installed in the frame and prevent the movement of falling out. <br> 7) rope <br> Rope steel wire of the minimum nominal strength should be greater .than or equal to 1570N/mm2, but if you exceed 1800N/mm2, mm2 calculation 1800N /. <br> <br> <br> <br> <br> <br> <br> <br> <br>.