【正文】 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。Control cabin leans on a part of the body side to fix four idles wheel ，Cause to dominate the cabin may go up and down along the guide in shelf part of the body outside ，Convenient operator is living , and the hoister to surface of the earth of upper air is dominateeed 。Suspending on the coop horn separately fixs berthhing the unit ，That unit stirs a string Gou in the interest of automate either hand ，When suspending the coop to berth ，Turns that unit causes it string to headframe master vertical column and fiercely fastens on the staff ，Geing up to ascend the wire rope does not accept force 。Relates to build up to the assembly pulley that suspends the ministry on coop peak consists of admittedly stably that the master who suspends the ministry on coop peak being living advances idle wheel and two assisting direction idles wheel 。在此我還要感謝我的家庭對(duì)我的支持，使我順利的完學(xué)業(yè)。還要感謝同組的其他同學(xué)，大家相互幫助，共同努力，克服了一個(gè)又一個(gè)的困難，最終完成畢業(yè)設(shè)計(jì)。在我們遇到困難時(shí)，兩位指導(dǎo)老師會(huì)幫助我們克服困難，戰(zhàn)勝困難。感謝學(xué)校給我提供良好的設(shè)計(jì)環(huán)境，讓我有一個(gè)安靜的設(shè)計(jì)教室，給我一個(gè)可以隨時(shí)查閱資料的圖書館，感謝其它給過我?guī)椭睦蠋熀屯瑢W(xué)。由于時(shí)間比較倉促，優(yōu)化效果并沒有達(dá)到最佳水準(zhǔn)，但是通過設(shè)計(jì)還是了解了制作的全部過程，達(dá)到了設(shè)計(jì)的預(yù)期目的。利用MATLAB軟件可以求解線性規(guī)劃、無約束規(guī)劃、,初始參數(shù)輸入簡單,符合工程設(shè)計(jì)語言,應(yīng)用該軟件求解機(jī)械優(yōu)化設(shè)計(jì)問題非常方便。通過計(jì)算選用機(jī)構(gòu)中所需的標(biāo)準(zhǔn)部件（如電動(dòng)機(jī)、制動(dòng)器、減速器、聯(lián)軸器、鋼絲繩等），對(duì)非標(biāo)準(zhǔn)零件還須作進(jìn)一步的強(qiáng)度與風(fēng)度計(jì)算校核。本次設(shè)計(jì)的任務(wù)主要是對(duì)起重機(jī)起升機(jī)構(gòu)設(shè)計(jì)及對(duì)抓斗的優(yōu)化。,options) 輸出最優(yōu)點(diǎn)和目標(biāo)函數(shù)值：x(1)= x(2)= x(3)=x(4)=與原設(shè)計(jì)方案x=(,)下目標(biāo)函數(shù)進(jìn)行比較,在整個(gè)抓取過程中,優(yōu)化方案單位閉合繩拉力產(chǎn)生的抓取力比原方案提高25%～31%。,x0,[],[],[],[],[],[],39。[x,fval]=fmincon(39。off39。largescale39。x0=[,]。%優(yōu)化約束；function [c,ceq]=confun(x)；c=[ x(1)^2(x(2)sin(x(4))x(3))^2(x(2)cos(x(4))+)^2/x(2)sin(x(4))x(3)/(x(1)+x(2))cos(x(4))x(3)/(2)/(3)/(4)/(x(2)*sin(x(4))x(3))^2+9x(4)cos(x(4))+)^2x(1)^2/x(1)+x(3)x(2)/x(4)]。，返回x處的函數(shù)值f。 （411） （412） (j=1,2,3,) （413）其中,和控制閉合滑輪組上、下滑輪軸閉合狀態(tài)下最小及最大距離,控制抓斗機(jī)構(gòu)最大寬度,與閉合滑輪組滑輪大小有關(guān),ρ為散料動(dòng)態(tài)堆積角。 (d)保證抓斗結(jié)構(gòu)緊湊。 （45）（b）避免閉合狀態(tài)下?lián)螚U力臂過小。=, =, =, =, =π/5。由于C為常數(shù),令 （43）則,長撐桿抓斗機(jī)構(gòu)的優(yōu)化函數(shù)為等價(jià)與 （44） 決定優(yōu)化目標(biāo)的獨(dú)立變量只有, ,及,并令, , , ,它們構(gòu)成了抓斗機(jī)構(gòu)優(yōu)化設(shè)計(jì)的設(shè)計(jì)變量。在抓斗閉合末期,增大可以獲得較大的水平閉合力,有利于將抓到的散料壓入顎板中,提高抓斗在閉合后期的填充能力?；蛘呖梢圆捎幂^寬的抓斗。在抓斗閉合初期,增大有利于減緩閉合繩拉力的增加,可以在較小的閉合繩拉力時(shí)有較大的抓取力,增加抓斗的下沉力。長度均以m為單位,角度以弧度為單位。圖12為抓斗機(jī)構(gòu)簡圖。若合理匹配機(jī)構(gòu)幾何尺寸,使相同開度下單位閉合繩拉力產(chǎn)生的抓取力提高,將有利于減輕抓斗自重,提高抓取比。 4 抓斗優(yōu)化抓斗抓取散料需要能量,長撐桿抓斗的這個(gè)能量主要通過閉合繩拉力及抓斗重心的垂直運(yùn)動(dòng)引起的重力勢(shì)能的改變獲得。制動(dòng)時(shí)間：制動(dòng)時(shí)，制動(dòng)器的制動(dòng)力矩促使運(yùn)動(dòng)質(zhì)量減速。 （39）式中[J]起升時(shí)換算到電動(dòng)機(jī)軸上的總轉(zhuǎn)動(dòng)慣量 （310）高速軸上旋轉(zhuǎn)質(zhì)量的轉(zhuǎn)動(dòng)慣量。這時(shí)起動(dòng)力矩除了克服靜阻力矩外，還有一部分力矩使運(yùn)動(dòng)質(zhì)量加速。因而必須把啟動(dòng)與制動(dòng)時(shí)間控制在一定的范圍內(nèi)。在啟動(dòng)和制動(dòng)時(shí)期，機(jī)構(gòu)作變速運(yùn)動(dòng)，因而 有加速度與慣性力的作用。眾所周知，起重機(jī)是一種間歇?jiǎng)幼鞯臋C(jī)械，工作是周期性的。據(jù)聯(lián)軸器標(biāo)準(zhǔn)， CLZ2半齒輪聯(lián)軸器最大允許扭矩 ，飛輪矩，自身質(zhì)量 ，制動(dòng)輪直徑D=200的帶制動(dòng)輪齒輪聯(lián)軸器最大允許扭矩飛輪矩 ，自身質(zhì)量輸入軸直徑，輸出軸直徑。起升機(jī)構(gòu)制動(dòng)器的制動(dòng)力矩必須大于由貨物產(chǎn)生的靜力矩，使貨物處于懸吊狀態(tài)時(shí)具有足夠的安全，下降靜轉(zhuǎn)矩為：查制動(dòng)器標(biāo)準(zhǔn)，選用YDWZ300/45制動(dòng)器，其額定制動(dòng)轉(zhuǎn)矩制動(dòng)輪直徑D=400mm，制動(dòng)器自身質(zhì)量 圖9 制動(dòng)器高速軸的計(jì)算扭矩 （311）式中，n——聯(lián)軸器安全系數(shù)，取 ； ——?jiǎng)傂詣?dòng)載系數(shù)，一般=。 圖8 減速器示意圖 貨物實(shí)際起升速度：減速器輸出軸強(qiáng)度校核：輸出軸最大徑向力 （37）式中 為卷筒與軸的自身重力，減速器輸出軸最大徑向力許用值[R]=86700N輸入軸最大扭矩 （38）式中j——電動(dòng)機(jī)最大扭矩倍數(shù)；i——為減速器的傳動(dòng)比；h——為減速器的效率。等效功率 （35）根據(jù)表327 ，查文獻(xiàn)[1]圖352起升機(jī)構(gòu)曲線1得g=，查文獻(xiàn)[1]表328得因此，初選電動(dòng)機(jī)能夠滿足不過熱條件。故應(yīng)對(duì)初選的電動(dòng)機(jī)作發(fā)熱驗(yàn)算，以控制電動(dòng)機(jī)的溫升，使在容許范圍內(nèi)。 圖7 電動(dòng)機(jī)電動(dòng)機(jī)發(fā)熱驗(yàn)算電動(dòng)機(jī)在工作時(shí)由于電流通過繞組而引起發(fā)熱，起動(dòng)時(shí)因電流較大，