帶式輸送機設計-傳動裝置【說明書+CAD+SOLIDWORKS】,說明書+CAD+SOLIDWORKS,帶式輸送機設計-傳動裝置【說明書+CAD+SOLIDWORKS】,輸送,設計,傳動,裝置,說明書,仿單,cad,solidworks 袋裝面粉輸送機的結構設計（論文） 附錄A 選工廠帶式輸送機功率配置選型的研究 帶式輸送機是化工、煤炭、冶金、電力等部門廣泛應用的連續(xù)運輸設備.在室內運輸中。它也是最主要的連續(xù)輸送設備之一。本文結合選工廠工藝系統(tǒng)自身的特點，談談在工廠在帶式輸送機功率配置和部件選型設計中的幾點體會，并概述帶式輸送機設計中的問題。 1 工廠帶式輸送 機的特點 概括起來，工廠的帶式輸送機具有以下特點運距短 ，一般在 150m以下 。運量小 ，1500t／h以下率低，110kW 以下；②帶速最大一般為2．5rids，有卸料器時不超過 2．0m／8；③布置形式也比較單一。以 TD75為主，采用頭部單滾筒 、單 電機驅動。拉置主要是螺旋拉緊、垂直重錘拉緊、車式拉緊三種數(shù)量多 ，運量 、帶寬等參數(shù)變化大，機長從幾米至米，功率從 5．5kW至上百千瓦都有：⑤運輸物料的變化大 。粒度從 0．5mm至 400mm以上 。含水率變比較大：輸送機的工作環(huán)境較差。 隨著生產的發(fā)展，工廠的帶式輸送機也出現(xiàn)些新 的特點 ，大運量、大功率 、多電機驅動 的輸送時常出現(xiàn)，對輸送機的可靠性也提出了新的要求。 2 帶式輸送機功率的配置 根據(jù)通常的設計思路。計算輸送機功率時，一據(jù)工藝流程得到的參數(shù) 。按最惡劣的工況計算 ，再適當?shù)母辉Ｏ禂?shù)，就近靠擋。由于工廠的帶式輸具有前面所講述的特點 。如按此方法設計 ，全廠輸驅動裝置的品種就很多。從現(xiàn)場的反映情況來看 ，這種設計思路有以下兩點值得探討 ： (1)由于工廠機械化程度的提高和開采技術的廣泛運用 。因此在流程參數(shù)的計算選取時 ，應適 當考慮到一 些極端情況 。輸送機 設計計算時，功率應留有足夠的富裕度。 (2)由于市場變化比較大 ，工廠往往有連續(xù)生產 的情況。對設備的可靠性要求越來越高 ；因此我們在設 計時要充分考慮到設備的可靠性和可維護性 ，首先對重要部件如驅動裝置要選用質量好 的產品，另外要減少主 要零部件 的品種 ，因為品種越多 ，需要的備品備件數(shù)量 就越多，不但增加了庫存量，而且增加了維修量。 對全廠的輸送機來講。設計時通盤考慮輸送機和其 他設備的功率 ，確定若干個功率檔 ，選用時功率就近靠檔。樣對一些小功率的皮帶 ，可能會造成一些功率浪費 ，但是 由于減少 了零部件的品種 ，整個工廠備品備件庫存降低 ，增加 了設備和互換性 ，反而會降低設備總投資 ，提高設備的可靠性和可維護性 。 以下是某礦儲裝運系統(tǒng)改擴建工程的帶式輸送機參數(shù)和計算功率調整 、靠檔的情況。 由表 1中可 以看出 ，調整前功率 有 1lkW、15kW、22kW、37kW 、55kW 、75kW 、220kW、250kW 共八檔，調整后輸送機的參數(shù)根據(jù)現(xiàn)場生產的實際情況進行了調整 (其中部分帶式輸送機的布置參數(shù) 也進行 了調整 )功率只有 37kW、55kW、90kW、250kw 四檔 ，其 它設備如斗提 、振動篩等設備的電機功率也統(tǒng)一考慮 ，這樣就減少了全廠的驅動裝置零部件備品備件數(shù)量 ，給設備維護和管理帶來 了便利。 上述提到的只是其 中一個實例 。由于不同的工程具體情況不同，調整檔次可能也不盡相同。功率靠擋時還應考慮到主要受力部件如滾筒 、膠帶 的匹配問題 ，力求做到技術性 、經濟性的統(tǒng)一。 3 部件的選型 目前 ，工廠帶式輸送機仍以 TD75型為主，TD7型功率適用于 185kW 下 ，從設計實踐中可以發(fā)現(xiàn) ，TD7型輸送機型譜中的部分零部件并不能完全滿足設計需求 下面通過對四個部件的選型分析來說明這一問題。 3．1 拉緊裝置 拉緊裝置是帶式輸送機的一個基本組成部分，是保證帶式輸送機正常工作的重要部件。工廠帶式輸送機應用比較多的拉緊裝置主要有螺旋式 、車式和垂直式三種。螺旋式拉緊裝置主要適用于小功率 ．行程短的輸送機 ，而垂直拉緊裝置則是利用 了輸送機走廊 的空間位置，與土建結構一起考慮，便于布置。 從可靠性和經濟性考慮 ，應優(yōu) 先考慮采 用車式拉緊，理由如下：①重錘拉緊裝置的比車式拉緊多了三個改向滾筒；②物料和水容易掉入輸送帶與拉緊滾筒之間而損壞輸送帶 、改變磨擦系數(shù) ，造成跑偏；特別是物料水分大，粘料嚴重而膠帶清掃不干凈時更容易 出現(xiàn)這種現(xiàn)象：③車式重錘拉緊布置比較靈活，拉緊重錘可以考慮用一個組合 ．也可以分成兩組相同的重錘組 ，利用滑輪組靈活改向的特點 ，充分利用空間。甚至可 以布置到上一層或下一層；④車式重錘拉緊結構簡單，可靠。因此 ，在空間許可的情況下 應優(yōu)先考慮采用車式拉緊裝置輸送機設計過程 中，經常會碰到這種情況 ：拉緊行程或功率超過了螺旋拉緊裝置的適用范圍 ，而采用車式或重錘拉緊置又嫌浪費。為解決這一問題，可以考慮采用螺旋拉緊裝置以外的其他固定拉緊裝置．如有一種手動蝸輪蝸桿尾部拉緊裝置，由于蝸輪蝸桿的傳動 比大 ，又有自鎖功能，而且?guī)в袖摾K卷簡，拉緊距離長，填補了拉緊裝置的空檔，而且解決了螺旋拉緊裝置兩個絲桿調節(jié)不同步時 ，易造成輸送機跑偏的問題。部分選煤廠如濟北礦區(qū)許 廠礦選煤廠 ，工廠儲裝運改擴建工程采用蝸輪蝸桿拉 緊裝置替代 了螺旋拉 緊裝置。應用效果較好。 3．2 驅動裝置 驅動裝置從大的方面分類主要有電動滾筒 ，電機減 速機兩大類 ，前者主要用于小功率輸送機 考慮實際情 況，選型時功率往往需要跳一 、二檔選取 ，而且從使用 情況上看 ，由于廠家制造水平參差不齊 。使用工作環(huán)境 比較差 ，散熱情況不好，油冷滾筒的使用情況不太理想 ， 一旦出現(xiàn)故障，由于傳動裝置和滾筒為一體 ，需要全部 更換，維修工作量較大。為改變油冷滾筒故障率高的情況 ，現(xiàn)在出現(xiàn)了外裝式電動滾筒 。電動機置于傳動滾筒 外面，改善了電機工作狀況 ，最大功率可達 1O0kW 以上。 TD75型輸送機驅動裝置的配置形式為 ：Y系列電機+柱銷聯(lián)軸節(jié)+ZQ (ZL、NGW)軟齒面平行軸減速器+十字滑塊聯(lián)軸節(jié) ：ZQ、NGW 驅動組合功率在 100kW 以下 ．ZL驅動組合功率為 115～185kW。 由于產品制造、設備安裝水平的不斷進步和對驅動裝置可靠性 、布置尺寸、可維護性等方面的要求不斷提高 ，原有的配置形式已不能完全滿足要求 ，驅動裝置的配置有許多產品可供選擇 ，DTⅡ型輸送機推薦的一種組合形式 Y系列電機+液力偶合器 f或梅花形彈性聯(lián)軸節(jié)1 +DBY、DCY 型 中硬 齒 面 圓錐 齒輪 減 速 器+ZL型 彈性柱銷齒式聯(lián)軸節(jié) ，電機功率 45kW 以上采用液力偶合器，它可 以改善輸送機 的起動性能 、過載保護可靠 、節(jié)約能耗 、多電機驅動時可以平衡荷載 。ZL型彈性柱銷齒式聯(lián)軸節(jié)制造、安裝和維護比十字滑塊聯(lián)軸節(jié)簡單方便 。 目前輸送機用減速器的種類 比較多 ．除前面提到的幾種外 ，還有引進國外技術制造的硬齒面減速器、國外進 口或國外生產、國內組裝的硬齒面減速器幾大類 ，設計時根據(jù)用戶的需求和工藝布置的需要靈活配置。 直交型的硬齒 面減速器 由于其體積小 、傳動效率 高、承載力大、使用壽命長、可靠性高，目前在大功率輸送機上特別是井下輸送機中得到廣泛應用，在小功率輸送機上也有推廣的趨勢。 當 Cpk~<1．00，過程能力不足 ，應分析原 因并采取必要的措施。改產品剝離強度過程能力分析圖如圖 3。 由實際工序能力圖可知．當分布中心與公差中心沒有重合 。可按照Cpk標準判斷 ，圖中Cpk的值是 1．5854，表明過程能力充足，是一種理想狀態(tài)。 企業(yè)要想加入全球產業(yè)鏈中，就必須按照國際統(tǒng)一的質量管理標準和方法進行質量管理 ．SPC正是這樣 一種有效的質量管理工具 。通過對過程質量進行動態(tài) 、 連續(xù) 的監(jiān)控 ，不斷地分析質量 問題中的各種影響因素 。 并進行針對性預防，達到了持續(xù)改進的目的。作者在某塑料彩印企業(yè)中成功地實施了 SPC．運用sPC工具對企 業(yè)產品進行 了分析 。在質量控制中起到極好的警示和預 防作用 。從而為提高產品質量 、降低生產成本起到事半 功倍的效果 ，為企業(yè)帶來豐厚的利潤。 實心軸 軸作為機械零件通常是一根圓柱形桿，用來支撐部件并隨部件一起轉動以接受和傳遞轉動和扭矩。往復式發(fā)動機的曲軸接受每一根曲軸通過活塞和連桿（滑塊-曲柄機構）傳來的轉動，并通過聯(lián)軸器、齒輪、鏈條或皮帶把轉動傳遞到變速箱、凸輪軸、泵和其它裝置。由曲軸通過齒輪或鏈條驅動的凸輪軸只有一根受力軸即輸入軸，但軸上的每一個凸輪都能把轉動傳遞給氣門的傳動機構溝。 輪軸通常的定義是車輪和皮帶輪能在其上旋轉的一根固定的圓柱形構件，但驅動汽車后輪的旋轉軸也叫輪軸，這可能是從過去馬車時代傳下來的。通常習慣上把機器上的短軸叫做主軸（或心軸），特別是指機床上安裝刀具和工件的軸。 在以前一個車間里所有的機器都由一個大電動機或原動機的，這樣就必須有一根同車間一樣長的主傳動軸（即天軸）通過皮帶把動力供給較短的副軸、中間軸或頂軸。這種主傳動軸是用一節(jié)節(jié)的軸裝配起來的，用剛性聯(lián)軸器固定在一起。盡管一般說來用單獨的電動機來驅動每一臺機器更為方便，并且現(xiàn)代的趨勢也是按照這個方向發(fā)展的，但現(xiàn)在仍有某些場合采用分組傳動更為經濟。 應力和變力 軸在轉動時承受剪應力，其大小取決于扭矩和斷面的尺寸。這個剪應力是軸的材料對作用扭矩所產生的抗力的一種量度。所有傳遞扭矩的軸都承受扭轉剪應力。 除剪應力之外，傳遞扭矩的軸還會產生剪切變形。扭轉的狀態(tài)通常用每單位長度的扭轉角來表示，即用軸的某一截面所轉過的角度來表示。 安裝齒輪和皮帶輪的軸不但會產生扭矩，而且還會產生彎矩，彎曲應力（在凸面是拉應力，在凹面是壓應力）的大小取決于兩軸承間的距離及軸的截面尺寸， 彎曲和扭轉綜合起來使軸內所產生的受力狀態(tài)比單純扭轉所產生的純剪切狀態(tài)或單純彎曲所產生的拉伸─壓縮狀態(tài)更為復雜。 對軸的設計工作者來說，重要的是要知道軸是否可能產生過大的發(fā)向應力或過大的剪應力以致?lián)p壞。如果扭轉一支粉筆，它必定在同軸線成45°角的平面上而不是在與軸線垂直的平面上斷裂。這是因為最大的應力就作用在這個平面上，而粉筆的抗拉強度是很差的。通常在設計鋼軸時要使彎曲和扭轉產生的最大剪應力小于規(guī)定的最大設計應力。 圓形截面的軸與其它截面的軸相比，在扎鋼上更易于扎制，且更易于加工，同時也易于支撐在軸承上。因此，在實際應用中很少使用非遠行截面的軸。此外，圓軸的強度和剛度，無論是在彎曲或是扭轉時，都較易與計算。最后，對一定量的材料來說，圓軸對一定的扭矩所產生的最大剪應力最小，而抗扭剛度則最大。 圓軸內的剪應力在表面最大，而在軸線部分則降到零。這就是說大部分扭矩是由表面和靠近表面的材料來承受的。 臨界轉速 用弓拉小提琴時琴弦會發(fā)生振動，同樣，支撐在兩軸承之間的圓軸也有一個自然的橫向振動頻率。如果軸的轉速與自然頻率重合，軸就處于臨界轉速并發(fā)出噪音。多半長的撓性軸比短的剛性軸更容易出現(xiàn)臨界轉速。軸的自然頻率可隨其剛度的增加而提高。 如果把一根細長桿的一端固定在天花板上，另一端支撐一個很重的圓盤，如果給圓盤一個起始的扭矩就把手松開，圓盤就會像扭擺一樣繞桿軸來回振動。振動的頻率取決于桿的抗扭剛度和圓盤的重量；桿的剛度越大且圓盤越輕則頻率越高。往復式發(fā)動機的曲軸也會產生類似的扭轉振動。特別是多拐曲軸和帶有很重飛輪的曲軸更是如此。每一個曲拐和與之相聯(lián)的連桿部分的作用就像一個小飛輪，并且對作為一個整體的曲軸來說，這些小飛輪能按很多種方式彼此安相反的方向與主飛輪反反方向地繞軸線來回振動。 當發(fā)動機運轉時，由連桿傳遞給曲軸的扭矩是波動的，如果曲軸的轉速使連桿的起伏推力以與軸的自然扭轉頻率之一相符合的速度傳遞，則扭轉擺動就將同軸的轉動疊加起來。這樣的轉速稱之為扭轉臨界轉速，它能導致軸的損壞。因此，已經設計了許多裝置來控制軸的振動。 撓性軸 撓性軸是把單根的心線或新心軸上繞成螺旋形金屬絲左向和右向重疊地緊緊繞許多層而制成的。這種軸借助裝在軸的兩端的專用配件連接到動力源和從動件上。也可以采用金屬或非金屬材料的撓性套來引導和保護撓性軸，但要封裝一定的潤滑劑。與實心軸相比，撓性軸可以彎成半徑小得多的弧形而不至產生超限應力。 對于把傳遞的動力拐幾個角和達到相當長的距離來說，通常利用撓性軸比利用皮帶、鏈條或齒輪裝置要經濟和方便。汽車上大多數(shù)速度表都是用撓性軸來驅動的，這根撓性軸從變速箱一直接到儀表板上。如果有一個閥門、開關或其它控制裝置處在難以達到的位置，可以用一根撓性軸從比較方便的位置來操縱。對于像噴砂器、研磨機和鉆孔機這樣一些手提式工具來說，撓性軸幾乎是必不可少的。 附錄B Preparation Plant Selection belt conveyor configuration of power Belt conveyor is chemical, coal, metallurgy, electricity and other departments widely used for transportation equipment. In the coal preparation plant. It is also the most important one for transportation equipment. This paper Washery of the characteristics of its own system, in turn coal preparation belt conveyor power configuration in preparation plant selection and design of the components Experience, and outlined the problems in the design of belt conveyors. The characteristics of a coal preparation plant belt conveyor can be summed up, the belt conveyor coal preparation plant will have the following features short distance, usually in the 150 m below. Small volume, 1500 t / h below the low rate, 110 kW below; ② with maximum speed is generally 2.5 rids, when a discharge is not more than 2.0 m / 8; ③ layout form of a single comparison. Mainly to TD75, a single cylinder head, single-motor drive. Latin America is home spiral tightly, tightly vertical weights, the number three car-tensioning, traffic, bandwidth and other parameters, the captain from a few meters to meters, power from 5.5 kW to 100 kW have : ⑤ changes in the transport of materials. Size from 0.5mm to 400mm and above. Moisture content of more variable: conveyor of the poor working environment. With the development of the production, coal preparation plant belt conveyor also some new features, large capacity, high-power, multi-motor-driven conveyor always there, the reliability of the conveyor also made new demands. 2 belt conveyor power configuration in accordance with the usual design ideas. Calculation of conveyor power, according to a process by the parameters. By the worst conditions, to appropriate the wealth factor, the nearest block on. As the coal preparation plant with a front-losers by about the characteristics. If this method of design, the whole plant lose the drive on many varieties. From the scene of the situation, the design of the following two points are worth exploring: (1) Since the increased mining mechanization and caving mining the extensive use of technology. Some mine occurrence conditions more complicated. Coal changes are considerable. Therefore, in the calculation of selected parameters process, due consideration should be given to some extreme cases. Such as when a fault on a very large volume of waste, coal ash high. In good conditions for local storage and coal quality can be very good. Conveyor design and calculation, the power should have a sufficient degree of prosperity. (2) changes in the market due to relatively large, coal preparation plant for the production is often the case. The reliability of the equipment increasingly demanding high so we should give full consideration to the design of equipment to the reliability and maintainability, the first of the important components such as the drive to choose good quality products, other key parts and components to reduce the Variety, variety, the more the need for the more the number of spare parts, will not only increase the inventory, and increase the volume of maintenance. The whole plant in terms of the conveyor. Take into consideration the design of conveyor and other equipment of power, identified a number of power stalls, when the optional power on a nearby stall. Some kind of low-power belts, may result in some waste of power, but due to a decrease of parts of the species, the coal preparation plant to reduce spare parts inventory, an increase of equipment and interchangeable, but will reduce the total investment in equipment and improve facilities The reliability and maintainability. Following is a shipment of ore reserve system expansion project to the belt conveyor and computing power adjustment parameters, relying on the case file. From Table 1 shows that the adjustment before the power is 1 lkW, 15kW, 22kW, 37kW, 55kW, 75kW, 220kW, 250kW total of eight stalls, after adjustment conveyor at the scene according to the parameters of the actual situation of production have been adjusted (some of them with - Conveyor layout parameters have also made adjustments) power only 37 kW, 55kW, 90kW, 250kw Sidang, other equipment such as bucket mentioned, shaker, and other equipment in electrical power also consider unification, thus reducing the entire plant Drive The number of spare parts spare parts for equipment maintenance and management of the facilities. The above-mentioned is just one example. Because of different circumstances of different projects, adjusting grades may also vary. Power on block hours should also take into account the main force components such as cylinder, the matching of tape-to-technical, economic unity. ? Selection of three parts At present, coal preparation plant is still TD75-based belt conveyors, TD7 apply to the power of 185 kW, from design practice can be found, TD7-type transport aircraft spectrum in some parts can not fully meet the design requirements Below through the selection of four parts to illustrate the problem. 3.1 tensioning device Tighten the belt conveyor installations is a fundamental component of [l]. Is to guarantee the normal work of the belt conveyor important components. Washery belt conveyor application of relatively large number of tensioning device main spiral, car-and three vertical. Spiral-tensioning device primarily applicable to small power. Trip short conveyor, and the vertical tensioning device is the use of the conveyor corridor space position, considered together with the civil engineering structure, easy layout. From the reliability and economic considerations, priority should be given a car-tensioning, for the following reasons: ① weights tensioning device-tighten the car more than three bend drum; ② materials and easy to fall into the water conveyor system Tension between the drum and damage to the conveyor system, change the friction coefficient, a deviation in particular water materials, Nien Liu serious and sweeping tape is not clean, more prone to this phenomenon: ③ car-weights tighten layout More flexible, tightly weights can consider the use of a combination. Can also be divided into two groups the same group of weights, flexible use of the pulley group bend to the characteristics of the full use of space. Even on a layout or to the next level; ④ car-weights tension structure is simple and reliable. Therefore, in the space permitted under priority should be given to using car-tensioning device conveyor design process, often encounter such a situation: tighten trip or power over the spiral tighten the application of the device, used-car Tension and a heavy hammer home or suspected of waste. To solve this problem, may consider using screw tensioning device other than the fixed-tensioning device. For a manual Worm Gear tail tensioning device, because the transmission ratio Worm Gear, another self-locking function, but with a wire rope Volume Reduction, tighten long distance, a tensioning device to fill the gap and solve the The spiral tensioning device two screw-conditioning does not sync, easy conveyor deviation caused the problem. North preparation plant as part of Jeju-mining area factories and mines coal preparation plant, Yankuang Group Jining No.2 coal mine reservoir expansion project shipment to use Worm Gear tensioning device replaces the spiral tensioning device. Application effective. 3.2 Drive Drive from the main aspects of classification electrical drum, motor reducer two major categories, mainly used for small former Conveyor power to consider the actual situation, when the Selection of power often requires a jump, second gear selection, but also from the use of the , Due to uneven levels of manufacturing factories. The use of relatively poor working environment, cooling the situation well, the use of oil-cooling drum is not an ideal situation, the event of a failure, due to transmission and drum as one, all the necessary replacement and maintenance workload greater. In order to change the oil drum cold of the high failure rate, now a foreign-mounted electric drum. Motor driving drum placed outside the motor to improve working conditions, the maximum power of up to 1 O0kW above. TD75-conveyor drive configuration form: Y-selling series of electrical coupling + + ZQ (ZL, NGW) soft tooth surface parallel shaft coupling slider reducer + Cross: ZQ, NGW combination of power-driven In the following 100 kW. ZL-driven combination of power for 115 ~ 185kW. As product manufacturing, equipment installation and the level of progress on drive reliability, layout size, maintainability, and other aspects of the request continuously improve, the original configurations can not fully meet the requirements, drive the allocation of many products To choose from, DT Ⅱ conveyor type recommended by the form of a series of electrical Y + hydraulic coupling f or a plum blossom-shaped flexible coupling + DBY, DCY-hardened in the bevel gear reducer + ZL-type flexible Pin Gear coupling, the electrical power of 45 kW over a hydraulic coupling, it can conveyor to improve the starting performance, reliable overload protection, energy saving, multi-motor drive, can balance the load. ZL-type flexible sales Gear coupling manufacture, install and maintain than the cross slider coupling easy and convenient. At present conveyor with the type of reducer more. In addition to the above-mentioned a few, there is also the introduction of foreign technology manufacturing Hardened reducer, foreign imports or production abroad, the national assembly Hardened reducer several categories, according to the design of the user's needs and layout of the The need for flexible configuration. Orthogonal-Hardened reducer because of their small size, high transmission efficiency, capacity, long life, high reliability, high-power transmission in the current crew in particular in the underground conveyor been widely used in small power on the conveyor Also promote the trend. When Cpk ~ <1.00, inadequate capacity process, should analyze the causes and take the necessary measures. Products to peel strength capacity analysis of the process in Figure 3. From the actual process capability map know. When the distribution center and Tolerance Center no coincidence. Cpk standards in accordance with the judgement, the map Cpk value is 1.5854, that the process of adequate capacity, is an ideal state. ? Enterprises to join the global industrial chain, must be in accordance with international unity on the quality of management standards and methods of quality management.SPC is such an effective quality management tools. Through the process of quality dynamic, continuous monitoring, analysis of the quality of the various factors. And through targeted prevention, to achieve a sustained improvement. The author in a plastic color printing enterprises in the successful implementation of the SPC. SPC use of tools for enterprise products were analyzed. In quality control and played an excellent pre-warning Anti-role. So as to improve product quality, reduce production costs play a multiplier effect for enterprises profits. Solid shafts. As a machine component a shaft is commonly a cylindrical bar that supports and rotates with devices for receiving and delivering rotary motion and torque .The crankshaft of a reciprocating engine receive its rotary motion from each of the cranks, via the pistons and connecting roads (the slider-crank mechanisms), and delivers it by means of couplings, gears, chains or belts to the transmission, camshaft, pumps, and other devices. The camshafts, driven by a gear or chain from the crankshaft, has only one receiver or input, but each cam on the shaft delivers rotary motion to the valve-actuating mechanisms. An axle is usually defined as a stationary cylindrical member on which wheels and pulleys can rotate, but the rotating shafts that drive the rear wheels of an automobile are also called axles, no doubt a carryover from horse-and-buggy days. It is common practice to speak short shafts on machines as spindles, especially tool-carrying or work-carrying shafts on machine tools. In the days when all machines in a shop were driven by one large electric motor or prime mover, it was necessary to have long line shafts running length of the shop and supplying power, by belt, to shorter couter shafts, jack shafts, or head shafts. These line shafts were assembled form separate lengths of shafting clampled together by rigid couplings. Although it is usually more convenient to drive each machine with a separate electric motor, and the present-day trend is in this direction, there are still some oil engine receives its rotary motion from each of the cranks, via the pistons and connecting roads (the slider-crank mechanisms) , and delivers it by means of couplings, gears, chains or belts to the transmission, camshaft, pumps, and other devices. The camshafts, driven by a gear or chain from the crankshaft, has only one receiver or input, but each cam on the shaft delivers rotary motion to the valve-actuating mechanisms. An axle is usually defined as a stationary cylindrical member on which wheels and pulleys can rotate, but the rotating shafts that drive the rear wheels of an automobile are also called axles, no doubt a carryover from horse-and-buggy days. It is common practice to speak short shafts on machines as spindles, especially tool-carrying or work-carrying shafts on machine tools. In the days when all machines in a shop were driven by one large electric motor or prime mover, it was necessary to have long line shafts running length of the shop and supplying power, by belt, to shorter coutershafts, jackshafts, or headshafts. These line shafts were assembled form separate lengths of shafting clampled together by rigid couplings. Although it is usually more convenient to drive each machine with a separate electric motor, and the present-day trend is in this direction, there are still some situation in which a group drive is more economical. A single-throw crankshaft that could be used in a single-cylinder reciprocating engine or pump is shown in Figure 21. The journals A and B rotate in the main bearings, C is the crankpin that fits in a bearing on the end of the connecting rod and moves on a circle of radius R about the main bearings, while D and E are the cheeks or webs. The throw R is one half the stroks of the piston, which is connected, by the wrist pin, to the other end of the connecting rod and guided so as to move on a straight path passing throw the axis XX. On a multiple-cylinder engine the crankshaft has multiple throws---eight for a st