Category and working principle: Tightener can be divided into hand pulled (wrench) hoist, ratchet tightener, and double hook tightener. (1) Hand pulled (hand pulled) hoists are mainly used to tighten various types of cables such as power and overhead lines, and to tow and move heavy objects such as equipment. They are also used to fix large equipment and other goods during automobile transportation. There are two types of driving methods for hand pull (hand pull) hoists: hand pull and hand pull. Hand pull hoists achieve the purpose of tightening and lifting by manually pulling the ring chain. Hand pull hoists include ring chain hand pull hoists and steel wire rope hand pull hoists. Hand pull hoists use handles to pull the ring chain or steel wire rope to achieve the purpose of tightening and lifting. Hand pulled (lever) hoists can be used for lifting, towing, lowering, calibration, and other operations. If equipped with special devices such as cable clamps, not only can non linear traction operations be carried out, but suitable operating positions can be easily selected, or the load capacity of smaller tonnage machines can be multiplied. For larger tonnage loads, multiple hand pull (wrench) hoists can be used for parallel operation. (2) Ratchet wire tensioner, also known as ratchet wrench hoist, is a tool used to tighten steel strands and small cross-section wires during transmission line construction. Usually, a wire clamp is used to fix the wire first, and then a wire tensioner is used to tighten the wire to a suitable sag. (3) The double hook tightener is a tool used for tightening the stay wire, adjusting the position of equipment or equipment, replacing insulators, and other tensioning during the construction process of transmission line engineering. There are two types of double hook wire tensioners: steel and aluminum alloy. The former is heavier but allows for a large bearing capacity, with a maximum capacity of 100kN tension; The latter is lightweight and convenient to carry and use, but the maximum load is generally not greater than 50kN. When using the tightener, first loosen the steel wire rope or galvanized iron wire on the tightener and fix it on the cross arm. Use a wire clamp to clamp the wire, and then pull the special wrench. Tightener can improve the safety of cargo transportation and lifting process. Attention: When using, the following points should be noted: (1) The corresponding specifications of wire tightener should be selected based on the thickness of the wire. When using, the steel wire rope should be straightened out and not twisted. (2) The ratchet and pawl should be intact and flexible, and there should be no tripping phenomenon. Oil lubrication should be added frequently during application. (3) When using a tightener, if any sliding wire is found, it should be immediately stopped and corresponding measures should be taken (such as wrapping a layer of iron wire on the wire) to firmly clamp the wire before continuing to use. [2] Application fields: Mechanical equipment for infrastructure projects such as construction, highways, bridges, metallurgy, mines, slope tunnels, and shaft protection