小型吊裝機的設計

小型吊裝機的設計,小型吊裝機的設計,小型,吊裝,設計 畢業(yè)設計（論文） 英文翻譯 年級、 專業(yè): 2007級機械設計制造及其自動化 姓 名: 郭 華 江 學 號: 312007080301509 指 導 教 師: 秦 小 嶼 Journal of Terramechanics Volume 48, Issue 2, April 2011, Pages 157-168 The design process of a self-propelled floor crane Daryoush Safarzadeh， Shamsuddin Sulaiman，F(xiàn)aieza Abdul Aziz， Desa Bin Ahmad，and Gholam Hossein Majzoobi Abstract In order to prevent the hazards associated with the crane application in workshops and factories, a self-propelled hydraulic floor crane with wire remote control was designed. The main focus was directed on remote control of the craneoperations such as rotation of booms, rear and forward movements, changing travel speed, steering, braking and hook rotation. This configuration prevents the hazards and damages which may be created due to the proximity of operator to crane and provides the feasibility of utilizing the crane in crowded manufacturing areas, fields and hazardous environments. Research into the stability of crane on a slope route was also performed to obtain the equations of stability in static and dynamic conditions and recognition of the ways to enhance the stability. To validate the research work, a scale-model prototype was built to test the manner of controlling the crane operations from afar. Research highlights ? We design a crane with wire remote control to decrease hazards and to improve performance. ? It can be used in hazardous environments and fields. ? Remote loading and unloading of payload are feasible by use of an articulated hook. ? We suggest appropriate approaches to convey huge loads and to suppress payload sway. Keywords: Crane Hazards; Hydraulic; Remote control; Self-propelled 1. Introduction Cranes are devices utilized for loading, unloading and transmitting the loads. They are profitable devices but hazardous in nature. We knew the crane activities responsible for 4% of the reported accidents and according to OSHA regulations, about 15.2% of crane events are occurred in manufacturing environments. Many researches have been performed regarding the causes of injuries and death from cranes 。Crane accidents have been grouped in the following categories according to NIOSH (National Institute of Occupational Safety and Health) report, including: swinging loads, overturning of cranes, falling loads, crushing between moving parts of cranes, falls of people from cranes, power line contact, overloading, contact the hook assembly with boom tip, obstruction of vision, assembly and disassembly of boom. Crane hazards are normally related to design and crane use. From a safety point of view, one of the most important issues in design of a crane is determination of stability. Stability of ranes has been studied by some researchers。 Weak segments, stress, strain, displacement, critical points and strength of parts under definite loads are determined by computer aided finite element analyses. Strength of the components versus the applied loads is determined based on FOS (factor of safety). For a safe performance, FOS is typically considered more than 1. Hydraulic floor crane is a kind of crane which has been used in workshops and factories from olden times. Basically, it is composed of a base, a column, a boom and a hydraulic cylinder for hoisting the boom. Nowadays, its application has been limited because of innumerable defects. The major research contribution of this paper is the use of CAD to design and develop a wire remote control hydraulic floor crane for the aims of decreasing the hazards, improving the performance and efficiency compared to the existing types and application in various locations such as hazardous environments and fields. Hence the main focus was directed on hazards reduction. Furthermore, the design has been also accomplished based on the required functions to perform the corresponding operations and employing peculiarities of the existing types considering their defects including hand-operated actuation, lacking of motor supplies, low safety, slow response and low speed。 2. Design process The proposed solution to control the sway is to install a platform for placing the payload during displacement 。Another benefit of this measure is to reduce overturning of the crane due to the pendulum motion of payload during displacement. Overturning issue can also be controlled by increasing the stability of crane through the appropriate static and dynamic analyses and fortification of the components as well as the correct selection of the crane dimensions. The other approach to decrease the hazards is to control the crane performance from a distance by utilizing a wire remote control system. This system prevents the hazards which are created by the fall of payload and objects on the operator or the fall of operator off the crane. Increasing visibility is another approach to reduce hazards and to increase safety. According to OSHA regulations, safe use of a crane is compromised when the vision of an operator is blocked and employees cannot see what the others are doing. The crane size alone limits the operator’s range of vision and creates blind spots. The crane boom may obstruct the operator’s range of vision. Often a load is lifted several stories high and the crane operator must rely upon others to ensure safe movement of the load being handled. The accidents due to the visibility problems are also occurred by other transporting devices such as lift trucks. Collins et al. found that visibility problems account for more than 80% of forklift truck related accident such as striking pedestrians or other vehicles, falling-off a ramp or loading dock and turning over by hitting obstacles. The visibility can be increased in two ways: (a) Movement of the operator slightly far from the crane increases his visibility to control the crane operations from every side. That is a significant issue especially in busy locations or when the crane is carrying a huge load which limits the operator visibility. (b) Installing the wired or wireless camera in various spots of the crane helps the operator to control the entire crane operations in out of reach and hidden areas from afar ( The entire crane systems are covered by a body to protect the moving parts and to prevent event to people. To enhance flexibility and maneuverability of the crane, a compacted size and a three-piece boom were proposed. A combination of an inverter and a DC electromotor with 4?kW power was utilized to control the rear and forward movement and changing speed of the crane from remote distance. However, in this system by varying the speed of rotation, torque will be maintained constant. Thus a mechanical system consists of several pulleys and belts were designed to reduce the initial speed and to raise the torque Therefore, changing speed by inverter will be accomplished in a limited range to give a travel speed between 0 and 2.88?km/h. The normal speed of travel is 2?km/h so that the operator can walk along with the crane The maximum speed is 2.88?km/h. For the speeds more than 2?km/h in traveling, the operator can sit on the body. The main part of the hydraulic system is directional control valve assembly consists of several four-way valves with three positions ，These valves are solenoid operated so that the port opening can be achieved by a current flow through the coils. A magnetic field provides electromotive force to move the especially shaped valve spool. This motion is opposed by a centering spring. The ports are represented by pump , the return tank, the actuator inlet chamber A and the actuator outlet chamber B ，Solenoid valves should be used in open-center system that in neutral, oil flows through the control valve and back to the reservoir. 3. Field application Development of the crane for application on fields and rough lands may satisfy some of the field requirements such as loading, unloading and displacement of the field implements and boxes of the crops and fertilizer. The conditions of the crane operation on fields differ from the smooth lands. These differences are related to the required power, traction force, wheel slip, rolling resistance, wind effect and stability of the crane which is exposed to the perpetual variations due to the irregularities of the ground and may eventually result in overturning of the crane. Hence, to adapt the crane for field application, some modifications in the wheel size and power would be required. For a driving wheel moving on the soil ，the soil reaction G is resolved into horizontal and vertical components. The horizontal component is assumed to act at a distance (r) below the wheel center and is divided into two forces, a gross traction force Ft and a rolling resistance force Rr. 4. Manufacturing process To ensure of the crane function, in addition to an initial scale-model, a small model of AC crane at a scale of 1:2.5 was also manufactured and the operations such as forward and rear movements, changing speed, rotation of booms, steering and hook rotation from remote distance were tested. Compared to the designed model, in this process some modifications were applied to drive system and location of solenoid valves due to the limitations at the provision of parts or lack of adequate space. The platform and body were not installed so that the internal sections of the crane to be in full view To control the hook operation, a wireless camera (model 803 color CMOS) with a receiver (A/V fine tuning type) was connected to the boom. The details were observed on a laptop. The entire crane operations could be controlled properly from remote distance via a control box which was located at the operator’s hands. 5. Stability analyses The most important process in design of a crane is stability considerations to satisfy the safety issues. This process includes the proper selection of dimensions, weight and shape in addition to analyze the status of the lateral and longitudinal stability of the crane. Stability analyses and determination of the rated capacity have been achieved in accordance with ISO 4305 standard 1991. 6. Conclusions This paper presents different aspects to design of a crane with the aim to decrease the hazards associated with the crane application in manufacturing and crowded environments. The design process was essentially focused on remote control of the crane operations. This permits the operator to control the crane functions from a definite distance to prevent presumptive damages by reason of falling the payload, power line contact, falls of operator, overturning, crushing the parts and collision which may be created by swinging of payload during operation. Furthermore, other recommendations have been also presented to reduce the hazards during the crane performance. For instance, installation of a platform to place the payload during transmission to stop the sway, utilization of camera to avoid collision where the visibility is limited and augmentation of the stability through the selection of appropriate dimensions, materials, load distribution and factor of safety. Results of the stability analyses denote the possible ways to improve the stability condition of the crane. Other considerations were also achieved to improve the crane performance, including selection of a three-piece boom and a compacted size to enhance flexibility and maneuverability. Performance rapidity could be also raised through the use of two discrete electro motors for hydraulic and drive systems. The design is promising for the future development in crane industry and control systems for robotic applications. 地面力學周刊 48期，第二版，2011年4月出版，第157-168頁 自動地板起重機的設計過程 Daryoush Safarzadeh， Shamsuddin Sulaiman，F(xiàn)aieza Abdul Aziz， Desa Bin Ahmad，and Gholam Hossein Majzoobi 摘要 為了防止吊車在車間和工廠的應用危險，一種自動遠程控制液壓地板起重機被設計而出。其主要焦點在遠程控制起重機，像旋轉吊桿，前進和后退運動。改變行走速度、轉向、制動和吊鉤的旋轉。這種裝置可以防止因起重機操作人員靠近起重機而帶來的危險，同時提供了起重機在擁擠的危險環(huán)境制造領域的可行性。研究起重機在斜坡穩(wěn)定性也能去獲得從靜態(tài)和動態(tài)穩(wěn)定性的方程，并且可以識別加強其穩(wěn)定性。為了驗證此項研究內(nèi)容，制造一個原型樣機去測試從遠程控制的起重機。 研究思想 我們設計了一個起重機用電線遠程控制去減少危害和改善績效。它可以用在危險的環(huán)境和領域里。遠程加載和卸載通過使用一種掛鉤來鉸接是可行的。我們用適當?shù)耐緩絹韨鬟f巨大的高負載并且可以一直有效載荷的搖擺。 關鍵詞：起重機危害；液壓；遠程控制；自動推進 1. 引言 起重機式一種用來裝卸并傳遞載荷的設備。他們是有用的設備但在本質(zhì)上很危險。我們知道起重機事故在報告中約有4%，并且根據(jù)職業(yè)安全與衛(wèi)生條例，約有15.2%的起重機事故發(fā)生在生產(chǎn)制造領域。很多研究表明起重機經(jīng)常導致人的的受傷和死亡。起重機安全事故已經(jīng)歸組入美國國家職業(yè)安全與衛(wèi)生院的類別，包括，擺動負載，起重機的顛覆，載荷下落，起重機活動件的破壞。人從起重機上墜落，電線接觸，過載，掛桿頂部的掛鉤連接，阻礙視線，起重機吊桿裝配和拆卸，起重機的相關危害通常參照美國國家安全手冊來設計起重機，其中最重要的一個問題是設計一個起重機的穩(wěn)定性，起重機已經(jīng)被一些學者所研究，弱區(qū)段、應力、應變、位移、臨界點和在一定載荷強度下的零件負荷是由計算機輔助進行有限元分析。部件的強度是考慮安全因素的基礎上由外載荷決定的。為了安全性能，安全因素通常應該超過1。液壓地板起重機是一種在以前已經(jīng)應用于車間和工廠的起重機?；旧?，它是由一個基座，一個圓柱，一個吊桿和一個液壓缸起重吊桿。如今，因為它有很多缺陷已經(jīng)很少應用，而此文的主要的研究貢獻在于運用計算機輔助設計去設計發(fā)明一個遠程控制的液壓地板起重機目的是為了 減少危害，相比在典型的各樣危險環(huán)境下提高性能和效率。因此主要焦點在危險的減少，此外，設計也已經(jīng)完成在要求的功能去履行相應的操作基礎之上采用獨特的安裝方式去解決包含起吊操作、電力不足、低安全性能、反應遲緩和低速度等缺陷。 2.設計過程 推薦的控制搖擺的解決方法是在移動時安裝一個安放有效負載的平臺。這個措施的另一個好處就是減少移動過程中起重機由于有效負載的搖擺運動而產(chǎn)生的翻轉可能。翻轉事件也可以通過增加起重機的穩(wěn)定性來控制。這些可以通過合理的靜態(tài)和動態(tài)分析，成分的加強以及正確的選擇起重機的維度實現(xiàn)。另一個減少危險的方法是利用有線的遠程控制系統(tǒng)遠距離控制起重機。這個系統(tǒng)可以防止由有線負載和操作員身上物體的掉落或者操作員掉下起重機產(chǎn)生的危險。增加能見度是另一個減少危險增加安全的方法。根據(jù)OSHA規(guī)則，起重機的安全使用會在操作員的視線被阻擋和被雇傭人不能看見其他人在做什么的時候得不到保障。只是起重機的大小就能限制操作員的視線范圍，制造盲區(qū)。起重機的吊桿可能會遮擋操作員的視線范圍。經(jīng)常是負載物升到幾層樓高，起重機操作員必須依靠其他人來保證被操作的裝載物的安全運動。靠其他諸如起重機的傳輸裝置也會由于能見度問題出現(xiàn)事故。Collins 發(fā)現(xiàn)能見度問題證明80%以上的叉式升降裝卸車事故與其相關，如疾步的行人或其他車輛，掉下斜坡或裝載碼頭，以及被撞擊障礙物打翻。 能見度可以通過兩種方式增加： (a)操作員一點點遠離起重機的運動會增加他從各方面控制起重機操作的能見度。那是一個有意義的事件，特別是在繁忙的地方或者是在起重機正在搬運一批限制操作員能見度的大貨物的時候。 (b)在起重機的不同區(qū)域安裝有線的和無線的照相機有助于操作員從遠處在不能及和隱藏的區(qū)域內(nèi)控制整個起重機的運作。整個起重機系統(tǒng)被主體覆蓋以保護運動零件，并防止對人的傷害。為了加強起重機的靈活性和機動性，推薦了緊致的尺寸和三片吊桿。反相器和四千瓦力的DC電動機相結合，用于控制前后運動和起重機遠距離改變速度。然而，通過區(qū)分旋轉速度，在這個系統(tǒng)中，將維持扭矩持續(xù)。那么機械系統(tǒng)由幾個滑輪組成，并且傳動帶被設計來減少原始速度，增加扭矩。 因此，采用變頻調(diào)速就可以限制運動速度在0和2.88km/h之間。正常的運動速度是2km/h，因此，操作人員可以跟著起重機的最大速度2.88km/h移動。移動速度超過了2km/h時，操作人員可以坐在機體上。主要的液壓系統(tǒng)部件定向控制閥是由四通閥在三個位置組成。這些閥門是螺旋管閥門因此端口的開啟可以通過一個線圈電流流過來完成，磁場可以提供電動力去驅動特殊形狀的閥門。這個運動是由置于中心的彈簧反向運動所成。在端口中用泵返回水池，執(zhí)行機構進口室A和出口室B在同一室。電磁閥在自然環(huán)境下可以運用在開放的中心系統(tǒng)下，油液流經(jīng)控制閥回到油缸內(nèi)。 3.田間應用 應用于田間和粗糙路面的起重機的發(fā)展會滿足一些田間諸如田間工具和莊稼和肥料盒子的裝載，卸載和移動要求。起重機在田間里的工作條件與在光滑路面上的工作條件不同。這些不同與所需動力，牽引力，輪滑，抗翻轉性，風的影響和起重機的穩(wěn)定性相關。這些不同由于地面的不規(guī)則而顯示了其永恒的多變性并可能最終導致起重機翻轉。因此，為了適應起重機的田間應用，就需要在輪胎大小和動力上做一些修改。對于在土地上行駛的驅動輪，土地反作用力G取決于水平成分和垂直成分。假定水平成分在輪胎中心下方一段距離(r)處作用并且分成兩種力，一個是總的牽引力F，另一個是抗翻轉力Rr。 4.制造過程 為了保證起重機的功能和最初的比例模型，也制造了一個1：2.5比例的AC起重機小模型。還測試了前后運動，改變速度，吊桿旋轉，遠距離轉向和吊鉤旋轉。與設計模型相比，由于零件供應限制或缺少足夠的空間，在此過程中，在驅動系統(tǒng)和螺旋管閥的位置上做了許多修改。平臺和主體部分未安裝以便起重機的內(nèi)部結構能夠從全局選擇。為了控制吊鉤的運作，一個帶收音機（A/V良好收聽型）的無線照相機（型號803，顏色CMOS）與吊桿連接。在電腦上可以觀察到所有細節(jié)。整個起重機操作能夠通過位于操作者的手中的控制盒子從遠距離合理控制。 5.穩(wěn)定性分析 設計一個吊機的最重要過程是考慮它的穩(wěn)定性和安全性能。這個過程包含適當?shù)某叽邕x擇，重量和形狀，以及起重機橫向和縱向穩(wěn)定性的分析。穩(wěn)定性分析和測定的額定容量已經(jīng)與ISO 4305標準1991年一致。 6.總結 本文呈現(xiàn)了設計一臺旨在減少事故的起重機的不同方面。這些事故與起重機在制造方面以及在擁擠環(huán)境下的運用相關。設計過程從根本上聚焦在起重機運作的遠距離控制上。這使得操作者能夠從一定距離處控制起重機作用來阻止可以預期的危害。有效負載下降，電線互接，操作者的摔倒，翻轉，壓壞零件和碰撞，這些可能因操作中有效負載的搖擺而產(chǎn)生。而且，在起重機施工中還有其他優(yōu)點也呈現(xiàn)出來了以減少危害。例如，在轉移過程中，平臺的安裝來放置有效負載以防止搖擺，在能見度受限的地方和通過選擇合適的維度，材料，裝載分布和安全因素爭論穩(wěn)定性的地方，使用照相機以避免碰撞。穩(wěn)定性分析的結果表示可能的方式來提高起重機的穩(wěn)定條件。也有其他的考慮來改善起重機的表現(xiàn)，包括選擇三片吊桿和緊致的尺寸以加強靈活性和機動性。通過分別為液壓系統(tǒng)和驅動系統(tǒng)使用兩個電鍍車也能提高運作速度。這種設計對于起重機產(chǎn)業(yè)和自動應用的控制系統(tǒng)的未來發(fā)展很有發(fā)展前景。