Working principle of crane

Gantry crane bridge crane is widely used. It is a lifting trolley erected on a fixed span column of a building, which is suitable for factories, mines, workshops and warehouses. Used for loading, unloading and lifting materials indoors or in the open air, its biggest feature is that it does not occupy the effective area of the electric hoist work site. Divided into: general, power station, riot prevention, electric single beam, electric single beam suspension, electric hoist, metallurgy, insulated crane. Gantry crane is also a kind of mechanical equipment for handling and loading and unloading materials within a fixed span, which is widely used in workshops, warehouses or open spaces. This crane is different from the electric hoist bridge crane in the bridge part. It has two small culverts and high legs at both ends of the main beam, and the traveling wheels of the cart are installed on the bottom beams of the legs and run longitudinally along the tracks laid on the ground. Divided into: general purpose, power station, shipbuilding portal, shore container crane, truss crane, etc. Operation knowledge of portal crane Operation rules of double-beam bridge crane 1. Before work, a. Check the brakes, hooks, wire ropes and safety devices according to the requirements of the spot check card. If any abnormal phenomenon is found, it shall be eliminated. B before turning off the main power supply, the operator must confirm that there is no one on the platform or track. When the power circuit breaker is locked or there is a notice board, the main power supply can only be turned off after the original relevant personnel remove it. Xiaonan 2. A. When lifting heavy objects for the first time in each shift (or when the load reaches the maximum weight), lift the heavy objects off the ground for 0.5m before putting them down, check the performance of the brakes, and then conduct normal operation. B. During the operation, the operator shall sound the alarm for the following operations as required. ① Lifting and putting down heavy objects; When driving big cars and small cars. (2) When the crane passes through with unclear sight, it should ring the alarm bell continuously; ③ When the crane approaches another crane in the bridge span. (4) Close to personnel when lifting heavy objects. C. operate according to the unified command signal. D. In case of sudden power failure during work, all controllers should be placed in the "zero" position, and the crane should be checked for normal operation before continuing to work. C. During normal operation, it is forbidden to brake and stop the crane and trolley when driving backwards; When changing the movement direction of cart and trolley, the baking-free brick machine of sand making machine must put the handle in the "zero" position, so that the mechanism can not run in the opposite direction until it stops running completely. D for a crane with two hooks, when the main hook and the auxiliary hook are interchanged and the heights of the two hooks are similar, the main hook and the auxiliary hook must work separately to avoid collision between the two hooks. E. Double-hook cranes are not allowed to lift two objects with two hooks at the same time; When the hoisting mechanism does not work, adjust its brake. Go to Taishan Scenic Area F. It is forbidden to park with a limiter and adjust the brake of the hoisting mechanism with load. G. Strictly implement the "ten don't hang" system: ① command signal is unclear or command is chaotic; (2) Don't hang it when it exceeds the rated lifting weight; (3) Improper use of slings or loose binding of objects; (4) There are people on the hanging objects or other floating objects that are not hung; (5) The brakes or other brake safety devices fail and are not suspended; ⑥ When the crane directly lifts heavy objects for processing, it does not lift them; ⑦ Stay and hang, but don't hang; Don't mention explosives; Pet-name ruby buried objects don't pull hanging; Attending with angular objects block mouth, not good not hanging pad; H. If any abnormality is found, stop the machine immediately, check the reason and eliminate it in time. 3. After the work is finished, a. Raise the hook to a certain height, park the cart and trolley at the designated position, and put the controller handle at the "zero" position; Pull down the switch handle of the protective box and cut off the power supply. Perform routine maintenance. C. do a good job of succession. Single beam bridge crane 1 operating procedures. Before work, a. Before the single-beam bridge crane with cab and the driver take over, the hook, wire rope, safety device and other components should be inspected according to the requirements of the spot check card, and any abnormal situation should be eliminated. B. Single-beam bridge cranes operated on the ground shall be inspected by special personnel in each shift according to the requirements of check card. If any abnormal situation is found, it should be ruled out. C before turning off the main power supply, the operator must confirm that there is no one on the platform or track. When the power circuit breaker is locked or there is a notice board, the main power supply can only be turned off after the original relevant personnel remove it. 2. A. During work, when lifting heavy objects for the first time in each shift (or when the load reaches the maximum weight), the heavy objects should be lifted off the ground for 0.5m before being put down, and the braking performance should be checked before normal operation can be carried out. B. Strictly implement the "ten no-hanging" system: ① the command signal is unknown or the command does not hang; (2) Don't hang it when it exceeds the rated lifting weight; (3) Improper use of slings or loose binding of objects; (4) There are people on the hanging objects or other floating objects that are not hung; (5) The brakes or other brake safety devices fail and are not suspended; ⑥ When the crane directly lifts heavy objects for processing, it does not lift them; ⑦ Stay and hang, but don't hang; Don't mention explosives; Pet-name ruby buried objects don't pull hanging; Attending with angular objects block mouth, not good not hanging pad; C. If any abnormality is found, stop the machine immediately, cut off the power supply, check the reason and eliminate it in time. 3. After the work is finished, a. Raise the hook to a certain height, stop the cart at the designated position, and put the controller handle at the "zero" position; Pull down the circuit breaker and cut off the power supply. Perform routine maintenance. C. do a good job of succession. Gantry/semi-gantry crane 1 operating procedures. A. Before work, the operator shall check the brakes, hooks, wire ropes, safety devices and other components according to the requirements of the routine check card, and eliminate any abnormality found. Loosen the track clamp. 2. At work, a. When lifting heavy objects for the first time in each shift (or when the load reaches the maximum weight), the heavy objects should be lifted 0.5 meters off the ground before being put down, and the braking performance should be checked before normal operation can be carried out. B. During the operation, the operator shall sound the alarm for the following operations as required. ① Lifting and putting down heavy objects; When driving big cars and small cars. (2) When the line of sight is not clear, the crane should continuously sound an alarm when exercising and passing; ③ When the crane approaches another crane within the span; (4) Close to personnel when lifting heavy objects. C. operate according to the unified command signal. D. In case of sudden power failure during work, all controllers should be set to "zero" position, and the crane should be checked for normal operation before continuing to work. E. During the normal lifting process of gantry crane and lifting trolley, it is forbidden to drive and stop by reversing and braking; When changing the movement direction of the cart and the cart, the handle must be placed in the "zero" position, so that the mechanism can not run in the opposite direction until it stops running completely. F for a crane with two hooks, when the main hook and the auxiliary hook are interchanged and the heights of the two hooks are similar, the main hook and the auxiliary hook must work separately to avoid collision between the two hooks. G. Double hook cranes are not allowed to lift two objects with two hooks at the same time; Non-working hook must be lifted to a height close to the limit position, and wire rope is not allowed to be hung on the hook. H. It is forbidden to stop with a limiter, and it is forbidden to adjust the brake of the hoisting mechanism with load. First, strictly implement the "ten don't hang" system: ① the command signal is unknown or the command is chaotic; (2) Don't hang it when it exceeds the rated lifting weight; (3) Improper use of slings or loose binding of objects; (4) There are people on the hanging objects or other floating objects that are not hung; (5) When the crane is lifting heavy objects, it can be directly processed without lifting; ⑥ Hanging askew; ⑦ Don't mention explosives; Don't pull the objects buried today; Pet-name ruby angular mouth objects, not cushion not hanging; Attending cadres illegal command not hanging; J the operator should pay close attention to the running direction and whether there are people or obstacles nearby. K the gantry crane for open-air operation shall be anchored after the work. When the wind force is greater than 6, generally stop working and lock the rail clamp of the machine. 3. After the work is finished, a. Raise the hook to a certain height, stop the cart at the designated position, and put the controller handle at the "zero" position; Pull down the switch handle of the protective box knife, cut off the power supply, clamp the rail or lock the windproof anchor of the machine. Carry out routine maintenance to ensure adequate nutrition in Zhang Yong. C. do a good job of succession. Gantry crane is a kind of deformation of bridge crane. At the port, it is mainly used for loading and unloading of goods and bulk cargo in the outdoor yard. Its metal structure is like a gantry, two legs are installed under the main load-bearing beam, which can walk directly on the track on the ground, and there can be overhanging cantilever beams at both ends of the main beam. Gantry crane is widely used in port freight yard because of its high site utilization rate, large working range, wide adaptability and strong versatility. 1. Types of gantry cranes Generally speaking, gantry cranes are classified according to the forms of gantry structures, main beams and spreaders. (1) According to the structural form of the door frame, it is divided into (a) full gantry crane: the main beam is not cantilevered, and the trolley is carried out in the main span. (b) Semi-portal crane: The leg height difference can be determined according to the site civil engineering requirements. (c) Double cantilever gantry crane: the most common structural form, with reasonable structural stress and effective use of site area. (d) Single cantilever gantry crane: due to the limitation of the site, this structural form is often selected. (2) According to the main beam structure, it is divided into (a) single-beam gantry crane: single-beam cantilever gantry crane has simple structure, convenient manufacture and installation, and small self-weight. The main beams are mostly derailed box frame structures. Compared with the double-beam gantry crane, the overall stiffness is weak. Therefore, this form can be adopted when the lifting capacity Q is less than Q≤50t and the span S is less than S≤35m. There are two types of portal legs of single main portal crane: L-type and C-type. L-shape is easy to manufacture and install, with good stress condition and light weight. However, there is less room to lift the goods through the legs. C-shaped legs are made into inclined or curved shapes in order to have a larger lateral space. In order to let the goods pass through the legs smoothly. (II) Double-beam bridge crane Double-beam bridge crane has strong bearing capacity, large span, good overall stability and many varieties, but its own mass is larger than that of single-beam gantry crane with the same lifting weight, and its cost is also higher. According to the difference of main girder structure, it can also be divided into box girder and truss. At present, box structure is widely used. 2. Representation method of portal crane The model of portal crane is represented by four main elements: code, rated lifting capacity, span and working level. (1) code means m: it means portal type, and the symbol after m is double-beam portal crane. Its signs are: MG, me, MZ, MC and MP. Mg- double-beam single trolley hook gantry crane; Me- double beam double trolley hook gantry crane; MDN-single beam single trolley grab gantry crane; MDS-- three-purpose gantry crane with single beam trolley. 3. Selection of Gantry Crane (1) Selection of Single-beam and Double-beam Gantry Crane In general, the lifting weight is below 50t, the span is within 35m, and there is no special use requirement, so the single-beam gantry crane should be selected. If the portal is required to be large in width and high in working speed, or heavy and long workpieces are often hoisted, the double-beam portal crane should be selected. (2) Span and Cantilever Length The span of the gantry crane is an important factor affecting the quality of the crane itself. When selecting the type, the span should be reduced as much as possible under the premise of meeting the equipment use conditions and meeting the span series standards. (3) The principle of determining the track distance (a) can meet the stability requirements of the gantry along the crane track direction; (b) The overall dimensions of the goods should be able to smoothly pass through the plane steel frame of the leg; (c) Note that there is a certain proportional relationship between the wheel track b and the span s, generally taking the wheel track b = (1/4— 1/6) s. (4) Determination of the distance dimension of the gantry crane. In the working process, there should be a certain space dimension between the external dimension of the gantry crane and the passage of goods and transport vehicles in the freight yard to facilitate loading and unloading operations. Generally, when loading and unloading vehicles within a span, the distance from the door leg should be kept above 0.7m, when the spreader is not working, the distance from the transport vehicle should be greater than 0.5m, and the time interval for goods to pass through the door leg should be greater than 0.5m.. (5) The selection of electrical equipment of the gantry crane should start well. It shall comply with the relevant provisions of GB/T 14406- 1993 on general gantry cranes.