18噸橋式起重機的設計—機械部分

18噸橋式起重機的設計—機械部分,18噸橋式起重機的設計—機械部分,18,橋式起重機,設計,機械,部分,部份 附錄1 Crane Work Needs More Technique Crane work needs more technology. Construction of tower cranes are the main vertical transportation equipment and also a measure of construction companies and equipment strength of the important logo, in today's increasingly competitive construction market, to meet the construction needs of many construction companies have bought the tower crane. With the tower crane at the construction site of the widely used by the tower crane accident also caused more and more to people's lives and property brought about great losses. According to national statistics, the departments concerned, the tower crane accident rate reached 2.77 percent. Its security problem is still the urgency of the construction Loose training, testing and oversight requirements for the people who work around construction cranes have fostered a false sense of security in our industry. The recent deadly tower-crane collapse at a congested New York City building site should be a wake-up call for us to question and step up our current safety practices. Training and testing is king when it comes to safety. But the construction industry is putting unqualified personnel in the seats of construction cranes, even with today's testing. In many places, no experience is necessary after passing a standardized test. One week of study will give some people enough knowledge to pass a certification examination, and then they can jump into the cab of a crane. Imagine that a commercial airline pilot had the same training as a certified crane operator. How would you feel the next time you decided to fly? In California, it takes more hours of training to wield a pair of scissors in a hair salon than to operate potentially dangerous lifting machinery. How does this make sense? Riggers and signal persons also need standard training and testing to ensure safety under the hook. Employers usually allow any craft to signal a crane on a jobsite, despite best practices that require only qualified people do so. How is it then that uncertified and untrained people are allowed to signal and rig under the hook of a licensed or certified operator? Tower cranes are particularly risky as urban sites become more congested, and the risk of a catastrophic event is very high during climbing operations. Yet most tower-crane climbing crews are trained in a non-traditional manner, via secondhand knowledge that has been passed down over time. The problem with this type of hand-me-down knowledge is that it changes over the years, leaving out small-but-important details along the way. This "osmosis" of knowledge leads crews to develop their own tricks for climbing cranes, often forsaking basic safety in an attempt to save time and energy. In many cases, there are no safety devices or alarms to warn of a serious problem. Climbing crews are subjected to pressures that affect safety-critical decision-making. It is not uncommon for climbs to continue with damaged or leaking hydraulic systems, out-of-adjustment or jammed guide rollers, often working in the dark and for extended hours. This "MacGyver" method of climbing, where every jump becomes a new adventure, should not be the norm. Climbing-frame designs vary among manufacturers, but the operational steps are similar in principle. The climbing process is relatively straightforward, with a mixture of physical work and technical procedure. It is not complex; it is more about knowing the proper sequence of what needs to be done and then following the steps, one by one, making sure each step has been successfully completed before moving onto the next. It is essential that everyone know exactly what is going on and what the dangers are at every stage. That's why the industry needs standardized training, testing and oversight for this work, including a practical assessment of competence. Technicians should have model-specific training directly from the manufacturer, along with a level of practical experience. Inspectors, too, should be required to have specific technical training. They should be independent from all aspects of installation and maintenance to allow for objective decisions. Key personnel on erection crews should have standard training and testing. When these needs are satisfied, crane operations should be carried out in strict accordance with the manufacturers' instructions, engineering principals and governmental laws. But industry stakeholders and lawmakers need to step up their lax standards to protect the public. New York City residents, who have seen their homes turned into dust and debris, would be shocked at the way the industry deals with these issues. The birth worldwide industry early post-war years, the crane industry came to an aImost complete standstill. By the end of the decade, however, crane construction had diversified and spread around the world and the industry seemed infused with newfound energy that left it flourishing as never before. Lightweight cranes that arrived on site ready for use came to dominate construction sites as people realised the advantages of not having to dismantle them between jobs. These new designs did away with the need to have other lifting equipment assisting during rigging - a big contrast to the cumbersome rigging of previous designs. But, before all this could happen came the horrors of the Second World War. By 1940 afl of Europe was completely caught up in the conflict. By the time the war ended, Europe and other parts of the world had been subjected to extraordinary political, economic and social changes that would affect the entire? fabric of society, including the construction and crane industries, for many decades to come. In the US, steam locomotives were starting to be replaced by diesel - by 1953 more than 50 per cent of all locomotives would be diesel. During the war the mass production of excavators, scrapers and cranes continued. 1940, for example, saw Thew launch the new 'Lorain Motocrane' series. This consisted of three cranes which, for the first time in history, were mounted on chassis built by the crane manufacturer itselfi The smallest crane, the MC-2, could lift 7.6 tonnes, the MC-2 9.9 tonnes and the MC-3 13.5 tonnes. These cranes were delivered to the army by the thousand, and were also mounted on portals for use as harbour cranes (the MC-4 model). The war had, of course, taken its toll on the number of able-bodied men available to work in the crane industry and there was a serious shortage of good crane drivers. At Thew, newcomers were taught crane operations over a two-day course presented by A C Burch, an experienced mechanic and graduate of the Naval Academy, and L K Jenkins. These two gentlemen were probably the originators of 'operator training' as we know it today. As they had actually designed the Motocrane, both knew it inside out and were pleased to pass on this knowledge. In response to the long-standing problems,in which the swinging angle of the hoisted load and the velocity of swinging angle is difficult to measure in engineering practice,a state observer is designed by the use of information about the crane trolley's position,and as a result,the trolley load-hoisting system combines with the state observer so conceived to form an online soft measurement system.By introducing the difference between the observer's output and that of the trolley load-hoisting system,and transmitting it to the output end of the observer upon gain vector adjusting by the observer,the pole points of the observer are configured on the same point at the negative real axle,thereby realizing a stable,fast soft measurement for the system variables.Simulation experiments show that:the online soft measurement system possesses a fairly high level of robustness;as the pole points grow,however,the soft measurement system grows in the scope of adaptability to changes in the hoisted ...更多l(xiāng)oad and in the length of the hoisting wire rope.But as the pole points overly grow,a sudden increase in measurement errors may occur either way;when the pole points are set,the result of a soft measurement is more sensitive to the length change of the hoisting rope than to the change of the hoisted load. 起重機的工作需要更多的科學技術 塔式起重機是建筑施工垂直運輸?shù)闹饕O備，也是衡量一個建筑施工企業(yè)裝備實力的重要標識，在當今競爭日益激烈的建筑市場，為滿足施工需要，很多施工企業(yè)都購置了塔式起重機。隨著塔式起重機在施工現(xiàn)場的廣泛使用，由塔式起重機引發(fā)的傷亡事故也越來越多，給人民的生命財產帶來重大損失。據(jù)國內有關部門統(tǒng)計資料表明，塔式起重機的事故率已達2.77%。其安全問題仍然是建筑施工中的憂患……起重機的工作需要更多的科學技術， 松散的培訓，測試和監(jiān)督的要求, 周圍的建筑起重機給這些工作的人樹立了一種虛假的安全感，在我們的行業(yè)。最近塔式起重機倒塌在一個繁忙的紐約市建筑地盤應敲響警鐘，提醒我們問題的存在，并加強我們目前安全的做法。 當談到安全問題時，訓練和測試是關鍵。不過，建造業(yè)是把不合格人員放在建筑起重機的駕駛位上，甚至沒有通過今天的測試。在許多地方，沒有任何經驗必須合格的通過標準化的測試。一周的學習將給予一些人足夠的知識足以通過認證考試，然后他們可以跳轉到的起重機的駕駛室。 想象一下一個商業(yè)航空公司飛行員和一個認證的起重機操作員有相同的訓練。你會如何感覺，下一次你決定要坐飛機？在加利福尼亞州，掌握一對剪刀在頭發(fā)沙龍比操作有潛在危險的起重機械需要更多的時間訓練。如何，這是否合理？ 裝配工人和發(fā)信號的人也需要標準的培訓和測試，以確保安全下鉤。雇主通常允許任何工人發(fā)信號指揮起重機上工地 ，盡管最佳做法是需要合格的人這樣做。怎么能允許那么無證和未受過訓練的人來代替有工作證或經核證的操作者呢？ 塔式起重機是特別危險的，尤其是在市區(qū)用地變得更加擁擠時。攀登行動更是一個風險的行動，其災難性非常高。然而，大多數(shù)塔式起重機攀登員的訓練，在一個非傳統(tǒng)的方式，通過二手知識已流傳一段時間。問題與這種類型的現(xiàn)成的知識是，多年來，留下來的非常少，但最重要的細節(jié)卻丟失了。這種“滲透”的知識，導致操作者只能發(fā)展自己的技巧攀登起重機，往往放棄基本的安全，企圖以節(jié)省時間和能源. 在許多情況下沒有安全裝置或警報來提醒嚴重的問題的存在。攀登人員容易遭受到影響安全性至關重要的決策所帶來的壓力。攀登時，使用損壞或泄漏的液壓系統(tǒng)，沒有任何的調整，這并不鮮見。在黑暗中工作和延長工作時間是時有發(fā)生的。這種攀登方法，其中的每一次攀登都會成為新的冒險，不應該作為規(guī)范被采納。 攀爬架的設計，在制造商之間存在不同，但設計的步驟在原則上是相似的。攀登過程中是相對比較明了的，配合著的體力勞動和技術程序。這是并不復雜，它是更多地了解知道正確的序列需要做什么，然后按照下列步驟，一個又一個，確保每一步在做下一步前成功完成。這是十分重要，每個人都清楚的知道事情進展的怎么樣，在每一個階段存在什么樣的危險。 這就是為什么業(yè)界需要規(guī)范的培訓，測試和監(jiān)督，其中包括一個實際的評估能力。技術人員應該隨著實際經驗的提升，直接從制造商哪里獲得標準訓練。視察員同樣也也須有具體的技術培訓。他們應獨立于安裝和維修的各方面，這由客觀決定。架設的關鍵人員應該有標準的訓練和測試. 當這些需要得到滿足，起重機作業(yè)應進行嚴格按照有關制造商的指示，工程原則和政府的法律。但業(yè)內人士和國會議員，要加強他們的寬松標準，以保障公眾利益?？吹阶约旱募覉@變成了塵埃和碎片的紐約市居民，會對處理這些問題的方式感到震驚。 戰(zhàn)后的前幾年，世界性的工業(yè)誕生了，起重機行業(yè)幾乎完全停止。然而到這個年代末，起重機的建造變得多元化并傳播到世界各地，它的前所未有的蓬勃發(fā)展似乎整個工業(yè)注入了新能源。輕型起重機投入到工作地點并準備作為主要機械，因為人們意識到了在工作間不用拆除他們的的優(yōu)點。這些新的設計也不再需要其他起重設備協(xié)助操縱——相比以前在安裝前要進行繁瑣的設計。但是，在這一切之前發(fā)生了恐怖的第二次世界大戰(zhàn)。到1940年，歐洲完全陷入了戰(zhàn)爭中。到戰(zhàn)爭結束后的幾十年來，歐洲和世界其他地區(qū)發(fā)生了巨大的政治，經濟和社會變化，將影響整個社會結構，包括建造業(yè)和起重機行業(yè)。在美國，蒸汽機已開始改為柴油機——到1953年超過百分之五十的機車將使用柴油機。戰(zhàn)爭期間，挖掘機，鏟運機和起重機的大規(guī)模生產在繼續(xù)。例如1940年，看到Thew推出新的'Lorain Motocrane'系列。這其中包括三種起重機，是歷史上首次自身安裝了底盤的起重機。最小的MC - 2 ，起重量達7.6噸， MC – 2起重量為9.9噸，MC – 3起重量為13.5噸。這些起重機許多被用于軍隊，有的還安裝在港口用作港灣式起重機（在MC - 4型） 。當然，這場戰(zhàn)爭已經削弱了能在起重機行業(yè)工作的健壯的男人的數(shù)量，并且優(yōu)秀的起重機司機嚴重短缺。在Thew ，一位畢業(yè)于美國海軍學院的經驗豐富的技工A C Burch和L K Jenkins進行了為期兩天的起重機業(yè)務課程的教授。這兩位紳士好比是我們今天所知的“經營者培訓”的創(chuàng)始人。他們實際上已設計了動力起重機，都深深地了解起重機，并很高興傳授這方面的知識。 針對工程實際中起重機吊重擺角和擺角角速度不易測量的問題,利用小車位置信息設計了狀態(tài)觀測器,小車吊重系統(tǒng)和觀測器構成在線軟測量系統(tǒng)。通過引入觀測器輸出與小車吊重系統(tǒng)輸出之間的差值并經過觀測器的增益向量調節(jié)送至觀測器的輸入端,將觀測器的極點配置在負實軸的同一點上,實現(xiàn)對系統(tǒng)變量穩(wěn)定、快速軟測量。仿真試驗表明,在線軟測量系統(tǒng)具有較強的魯棒性;隨極點增大,軟測量系統(tǒng)對吊重和繩長變化具有更寬的適應范圍,但極點過大時,會出現(xiàn)測量誤差上沖或下沖現(xiàn)象;當極點確定時,軟測量效果對繩長變化比吊重變化敏感。