抓斗結構設計與優化_畢業設計論文-資料下載頁

【導讀】合適的卷筒、滑輪直徑。根據設計計算選定減速器、電動機、制動器和聯軸器。計算的結果，繪制出抓斗部件圖和起升機構總體裝配圖。利用MATLAB軟件可以求解線性規劃、無約束規劃、二次規劃和有約束非線性規劃等優化。化實例可以看出,應用該軟件求解機械優化設計問題非常方便。

　　

【正文】 tch particular grabbing or lifting requirements. Types Bridge cranes are available in top running and underhung configurations, and single or double girder, to match plant structural and lifting requirements. Gantry cranes are constructed in single or double leg, single or double girder, and top running or underhung versions. Bridge cranes are usually used for high tonnages, long spans, and heavy duties. Although available in several forms, each crane design contains several pieces of mon equipment. * Hoists are used to lift and lower the load. * Trolleys consist of a frame, end trucks or wheels with side frames, and drive. They suspend or support the hoist, rope, and load block。 and travel on one or more bridge rails or beams. * Girders are the principal horizontal structural steel beams holding the hoist and trolley. They are supported by end trucks and are perpendicular to the runway. Very wide or large capacity cranes require two or more girders. * Runways consist of structural steel rails, girders, brackets, and framework. They support and allow movement of the crane through the plant. * End trucks are an assembly of structural members, wheels, bearings, and axles that support the girders or trolley cross members. * Bridges consist of girders, end trucks, walkways, cross bridge electrification controls, and drive mechanisms. They carry the trolley and travel along the runway rails. Gantry cranes are often a practical alternative to bridge cranes, and are capable of serving many of the same lifting, traveling, and duty classifications. This floormounted equipment essentially bridges the lifting and moving service area as the crane rolls down a predetermined path on legs. Gantries are suitable if the plant structure cannot handle the bridge loading, if the installation is temporary and may require relocation at a later date, or overhead runways are long, costly to erect, and difficult to maintain in alignment. The gantry is mon in situations where the crane itself does little or no traveling, and material transfer is handled almost exclusively by the trolley. Toprunning double girder Toprunning, doublegirder cranes provide the greatest lifting capacities, highest tonnages, 姓名：董浩良 題目：抓斗結構設計與優化 30 widest spans, and heaviest duties. Toprunning single girder Toprunning, singlegirder cranes have a onebeam bridge that rides on a rail atop the runway and handle loads up to 30 tons with spans up to 60 ft. Doublegirder underhung Doublegirder underhung cranes have the hoist mounted above the bridge to attain a bit more headroom and reach capacities up to 50 tons. Singlegirder underhung Singlegirder underhung cranes have the bridge end trucks running on the lower flanges of the runway beams and are usually limited to 10 tons. Doubleleg gantry Doubleleg gantry cranes move along floor rails or guidepaths with a capacity typically less than 30 tons, although units reaching several hundred tons are in service. Singleleg gantry Singleleg gantry cranes substitute a wallmounted runway for the second leg and are usually designed to handle loads of less than 20 tons for a specific operation. Single and doubleleg, singlegirder cranes typically handle less than 20 tons, although models that acmodate up to about 60 tons are available with special construction features. The two doublegirder types usually have capacities less than 30 tons, but again, exceptions exist and some versions moving several hundred tons are in service. For more information on cranes, visit the Material handling channel at [Sidebar] Safety first [Sidebar] Safe crane operation is an issue of paramount importance. Components such as redundant brake concepts for hoists, more reliable controls, and economical overload detection systems are engineered into the cranes to help in the safety process. Even with this equipment available, safety starts with the operator. Whenever there is doubt as to safety, the operator should stop the crane, report the problem to a supervisor, and not operate the equipment until satisfied it is safe to do so, or is directed to proceed by a supervisor. Operators should be familiar with the principal parts of the crane. Employees should receive hands on training, read all instruction materials, and have a thorough knowledge of crane control functions and movements. The operator should test all crane controls at the beginning of each shift, and should perform a walkaround check to look for loose or damaged parts before mencing work. There is a variety of other safety factors to consider. * When the load approaches the rated capacity, the operator should test the hoisting brakes by raising the load a few inches and applying the brakes. * The load should not be lowered below the point where less than two full wraps of wire rope remain on the hoist drum. [Sidebar] * The operator should land any attached load and place the controllers in the off position when leaving a crane unattended. * Loads should never be carried over workers39。 heads. * Cranes should never be used for side pulling. 華東交通大學畢業設計 31 * Hand signals between the operator and hooker should be clearly agreed upon and understood before moving a load. * The operator should never lift two separately rigged loads at the same time. * The operator should approach the desired position as far as possible at the main speed and use creeping for final positioning. Ropes,pulleys and drums Steel Wire Ropes Steel wire ropes are used as flexible appliances to lift loads and transmit motion and forces. Such ropes are wound from steel wire from mm to 2 mm in diameter and have an ultimate strength of 1400— 20xxN/ wire ropes are available in a great variety of designs. Machines used in a