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黄河科技学院毕业设计（论文）开题报告表课题名称多层建筑小型电梯门禁系统设计课题来源教师拟订课题类型AX指导教师学生姓名专 业机械设计制造及其自动化学 号一、调研资料的准备根据任务书的要求，在做本课题前，查阅了与课题相关的资料有：机械设计、机械制图、机械制造工艺学、机械设计手册、机械工程手册、冷冲模课程设计与毕业设计指导、电梯国家标准等以及与设计相关的手册。二、设计的目的与要求 毕业设计是大学教学中最后一个实践性教学环节，通过该设计过程，可以检验学生所学的知识，同时培养学生处理工程中实际问题的能力，因此意义特别重大。编制电梯门工艺规程，根据所确定的工艺规程进行相应的方案设计、总体设计及其主要零部件设计，绘制电梯门总装图及主要零部件图等图纸。 三、设计的思路与预期成果 1.设计思路本设计传动系统为由手动按钮向plc发出指令，经plc处理后发出动作指令，使电动机开启，经带传动带动开门机，使电梯门实现开关的动作，由限位开关控制电梯门的行程，主要设计了电梯开关的开门机等。2.预期的成果（1）完成文献综述一篇，不少与3000字，与专业相关的英文翻译一篇，不少于3000字 （2）完成内容与字数都不少于规定量的毕业设计说明书一份（3）绘制装配图，部分零件图（4）刻录包含本次设计的所有内容的光盘一张四、任务完成的阶段内容及时间安排 1 周4 周 完成开题报告、文献翻译、文献综述及总体方案设计 5 周10 周 完成总体设计、完成部分机构的装配图及部分零件图并撰写说明书 10 周12 周 修改论文、资料审查等 13 周 毕业答辩五、完成设计（论文）所具备的条件因素 本人已修完机械设计、机械制图、机械原理、液压与气压传动、金属工艺学、机械制造技术基础、冲压成型工艺与模具设计、冷冲模课程设计与毕业设计指导等课程，借助图书馆的相关文献资料，以及相关的网络等资源。指导教师签名： 日期： 课题来源：（1）教师拟订；（2）学生建议；（3）企业和社会征集；（4）科研单位提供课题类型：（1）A工程设计（艺术设计）；B技术开发；C软件工程；D理论研究；E调研报告 （2）X真实课题；Y模拟课题；Z虚拟课题要求（1）、（2）均要填，如AY、BX等。 黄河科技学院毕业设计 第 6 页 毕业设计(论文) 文献综述 院（系）名称工学院机械系 专业名称机械设计制造及其自动化 学生姓名 指导教师 2012年 03 月 10 日多层建筑小型电梯门禁系统设计文献综述1 电梯的由来在现代汉语词典中电梯的解释为：建筑物中用电作动力的升降机,代替步行上下的楼梯。说到电梯的起源要从公元前2600年埃及人在建造金字塔时使用了最原始的提升系统说起，但这一类起重机的能源均为人力。到了1203年，法国的二修道院安装了一台起重机，所不同者只是该机器是利用驴作为动力，载荷由绕在一个大滚筒上的绳子进行起吊。此种方法一直沿用到近代直到瓦特发明了蒸汽机，约在1800年，煤矿主才能利用起重机把矿井中的煤输送上来。数百年来人们制造过各种类型的升降梯，它们都具有一个共同的缺陷：只要起吊绳突然断裂，升降梯便急速地坠落到底层。 前两代无机房电梯目前在欧洲已经淘汰，淘汰的原因是安全隐患严重，所以在1997年开始几乎没有欧洲公司再使用该类无机房电梯了。而第三代无机房电梯属于改变前两代无机房电梯的新产品，所以一时受到青睐。但是主机放在轿厢顶部的安全问题及噪音十分不受欢迎，所以在欧洲也没有得到发展。在第三代无机房电梯受到发展的只有通力的电梯。 但是通力的产品虽然比前两代有了技术方面的突破，特别是主机的突破应该说对无机房技术的普遍应用提供了十分好的契机；不过共振共鸣问题没有彻底解决是一个重要的技术设计缺陷。同时该种技术限制了速度及提升高度的提高。2 电梯的历史发展 电梯进入人们的生活已经150年了。一个半世纪的风风雨雨，翻天覆地的是历史的变迁，永恒不变的是电梯提升人类生活质量的承诺。 人类利用升降工具运输货物、人员的历史非常悠久。早在公元前2600年，埃及人在建造金字塔时就使用了最原始的升降系统，这套系统的基本原理至今仍无变化：即一个平衡物下降的同时，负载平台上升。早期的升降工具基本以人力为动力。1203年，在法国海岸边的一个修道院里安装了一台以驴子为动力的起重机，这才结束了用人力运送重物的历史。英国科学家瓦特发明蒸汽机后，起重机装置开始采用蒸汽为动力。紧随其后，威廉汤姆逊研制出用液压驱动的升降梯，液压的介质是水。在这些升降梯的基础上，一代又一代富有创新精神的工程师们在不断改进升降梯的技术。然而，一个关键的安全问题始终没有得到解决，那就是一旦升降梯拉升缆绳发生断裂时，负载平台就一定会发生坠毁事故。 生活在继续，科技在发展，电梯也在进步。150年来，电梯的材质由黑白到彩色，样式由直式到斜式，在操纵控制方面更是步步出新手柄开关操纵、按钮控制、信号控制、集选控制、人机对话等等，多台电梯还出现了并联控制，智能群控；双层轿厢电梯展示出节省井道空间，提升运输能力的优势；变速式自动人行道扶梯的出现大大节省了行人的时间；不同外形扇形、三角形、半菱形、半圆形、整圆形的观光电梯则使身处其中的乘客的视线不再封闭。如今，以美国奥的斯公司为代表的世界各大著名电梯公司各展风姿，仍在继续进行电梯新品的研发，并不断完善维修和保养服务系统。调频门控、智能远程监控、主机节能、控制柜低噪音耐用、复合钢带环保一款款集纳了人类在机械、电子、光学等领域最新科研成果的新型电梯竞相问世，冷冰冰的建筑因此散射出人性的光辉，人们的生活因此变得更加美好。3 今后一段时间内电梯技术发展趋势是什么?3.1 绿色化 从减少环境污染的角度讲,“绿色”新概念将成为21世纪的主流色调,一个全球性的绿色市场为提供了广阔的空间,21世纪谁先推出绿色产品,抢占绿色营销市场,谁就能掌企业的发展握竞争的主动权。绿色理念是电梯发展总趋势。发展趋势主要有如下: 不断改进产品的设计,生产环保型低能耗、低噪声、无漏油、无漏水、无电磁干扰、无井道导轨油渍污染的电梯。电梯曳引采用尼龙合成纤维曳引绳,钢皮带等无润滑油污染曳引方式。电梯装璜将采用无(少)环境污染材料,电梯空载上升和满载下行电机再生发电回收技术,安装电梯将无需安装脚手架,电梯零件在生产和使用过程中对环境没有影响(如刹车皮一定不能使用石棉)并且材料是可以回收的。3.2 降低能耗 减少电梯能耗的措施是多方面的。主要包括:选择高效的驱动系统;减小电梯机械系统的惯性和磨擦阻力;合理运用对重和平衡重。1、驱动系统使用永磁同步无齿轮曳引机,从永磁同步电机工作原理可知其励磁是由永磁铁来实现的,不需要定子额外提供励磁电流,因而电机的功率因数可以达到很高(理论上可以达到1)。同时永磁同步电机的转子无电流通过,不存在转子耗损问题,一般比异步电机降低45%60%耗损。由于没有效率低、高能耗蜗轮蜗杆传动副,能耗进一步降低。2、在停站较少的群梯布置中,一个主机驱动两个轿厢分别上下运行是一种节能的方案。而减少能耗的另一途径是电梯运行过程的能耗控制。利用电梯空载上行、满载下行时电机处以发电状态的特性,将再生能量反馈给电网,这种节能措施在高速梯上效果显著。3、还有一种节能方案将在软件控制中得以实现。如建立实时控制的交通模式,尽量以较少的运行次数来运载较多的乘客,使电梯的停站次数减至最少。电梯召唤与轿厢指令合一的楼层入口乘客登记方案是电梯控制方式的一项革命性技术,使原来层站上乘客未知的目的层变得一目了然,从而使控制系统的派梯效率达到最高。4、减少运行过程能耗的另一措施是将电梯运行中的加减速度模式设置成变参数,即电梯控制系统中运行的速度、加速度以及加速度变化率曲线既随运行距离变化,也随轿厢负载变化。通过仿真软件模拟,确定出不同楼层之间的最佳运行曲线。5、利用电梯机房在楼顶的优势,充分利用太阳能作为电梯的补充能源也将是新的研究课题。3.3 智能化 随着计算机技术,通讯技术与控制技术的发展使大厦的智能化成为现实,而电梯是智能建筑中的重要交通工具,其技术发展及智能化程度也倍受世人关注。智能化的电梯首先要与智能大厦中所有自动化系统联网,如与楼宇控制系统、消防系统、保安监控系统等交互联系,使电梯成为高效优质、安全舒适的服务工具。串行通讯以其布线简单,传输信息量大等优点,在电梯控制系统中应用日益增多。由于去掉了微机接口板上大量输入和输出电路,减少了井道、机房中的布线数量,可靠性大大提高。 随着大楼智能化的提高,现场总线技术现已开始应用于电梯控制系统与大楼的BAS,FAS,SAS中。从电梯运行的控制智能化角度讲,要求电梯有优质的服务质量。控制程序中应采用先进的调度规则,使群控管理有最佳的派梯模式。现在的群控算法中已不是单一地依赖“乘客等候时间最短”为目标,而是采用模糊理论、神经网络、专家系统的方法,将要综合考虑的因素(即专家知识)吸收到群控系统中去。在这些因素中既有影响乘客心理的因素,也有对即将要发生的情况作评价决策,是专家系统和电梯当前运行状态组合在一起的多元目标控制。利用遗传算法对客流交通模式及派梯规则进行优化、自学习,实现电梯调度规则的进化,以适应环境的变化。“以人为本”设计的电梯控制系统,将会使电梯的服务质量越来越好。3.4 远程监控技术的应用 电梯困人故障一直困扰着电梯的承包商,上世纪80年代初就有电梯厂商对电梯增加了过程监视系统,即在电梯轿厢内装设摄像和通讯系统,被困轿厢中的乘客可以同大楼的监视人员建立联系。由于这种设施只限于电梯所在大楼,且由保安人员负责,一旦电梯困人,还得通知专业人员来解困。而现在提出的远程监控服务系统是在远程监视系统上更进了一步,这种先进装置集通讯、故障诊断、微处理机为一体,它可以通过市话线传递电梯的运行和故障信息到远程服务中心(即电梯远程监控维修中心),使维修人员知道电梯问题所在并去处理。如轿厢由于发生门故障而被困于某层,远程维修中心根据故障状况判断后,则可允许用遥控方式来打开轿门和层门,在无维修人员到现场的情况下,被困人员就可以离开轿厢。如有的故障只能维修人员到现场排除的话,为使被困人员安心,中心即刻向轿厢播放安扰语音,解除紧张心理。自动扶梯安装远程监控后,除了能监视运行状况外,监控维修中心可根据显示的信息作出快速的急停处理,以免发生伤害事故。远程服务对用户的受益是显而易见的,电梯的远程监控不仅使用户得到一个部件、而且使用户享受到一整套的服务。远程维修监控中心始终监控着他们所承包的电梯,随时可以知道电梯的运行状态和发生故障的属性,维修人员去故障梯之前就已知道该维修的项目,减少了维修服务的成本和时间,这种预保养式的售后服务方式在国外是深得用户的信赖的,也将是我国电梯工业技术发展的一个重要方向。3.5 蓝牙技术的应用1、蓝牙技术在电梯安装过程的应用。安装过电梯的人都知道放线、对线是费时、费力、极容易错的工作。应用蓝牙技术,安装期将减少30%以上,其直接好处是降低安装成本,客户也因从订梯到使用电梯周期费用减少和提高现金周转率。2、在电梯上使用蓝牙技术一定会使电梯控制系统大量使用最新最快微机,这将会进一步提高电梯整机可靠性,故障率大大降低,控制精度也进一步提高,带来的结果是电梯更加舒适,平层更加准确。同时也为将来通过网络检查电梯状态成为可能,特别是电梯事先维修可以做到更好更全面。3、旧梯改造更加容易,所需时间、费用将会减小。据统计每年将有5万台旧梯进入更新改造市场,该技术使用将会产生巨大社会效益和企业效益。4、很好地解决了电梯控制与外围设备的兼容和联系。特别是可以把电梯和扶梯归纳到大楼管理系统或智能化管理小区系统中。5、如果控制屏与召唤系统通过蓝牙技术连接起来实现无线召唤,将会是电梯控制的另一场革命,同时为我们带来巨大好处。4 可编程逻辑控制器 简称PLC( Programmable Logical Controller) 是一种专门为适应工业环境而设计的工业控制计算机。它自1969 年问世以来，随着微电子技术，集成电路技术，微处理器技术和微计算机技术的发展，已经取得了巨大的进步。现在的PLC不仅已经大大超过了设计的初衷(即替代继电接触器)，用逻辑编程取代了硬连线逻辑，而且在容量，速度，功能和通信能力等方面有了大大的增强。现在的PLC由于采用了功能强大的高档微处理器(如16位，32位微处理器)，处理速度快，存储容量大大增加;由于采用了多种编程语言和先进的指令系统，增强了过程控制和数据处理的功能，如PID控制，数据文件传送，浮点运算功能，同时，完善的输入/输出系统使得系统的处理能力和控制能力得到大大加强;由于采用了现代数据通信和网络技术，能实现PLC之间，PLC和管理计算机之间的网络通信，形成多层分布式控制系统或整个工厂的自动化网络。现代的PLC还有图形显示，信息存储，多CPU并行工作等功能，这使得PLC的功能更加完善，足以满足绝大多数的生产控制要求。正是基于以上这些优势，现在的PLC已经成为工业控制中占主导地位的设备，并被广泛的应用于工业自动化的各种场合，因此，了解和掌握PLC系统的开发方法就日益成为我们的需要了。本次毕业设计的主要任务就是基于plc的电梯系统程序，首先，提出了设计的预期功能和控制要求，然后着重介绍了基于PLC的电梯系统程序开发过程，如电梯系统的静态呼叫控制，动态呼叫控制，紧急呼叫控制，;最后又针对本次设计方案提出了一些改进意见。实现了plc的电梯系统的控制功能，成功开发了基于plc的电梯系统程序。结束语:电梯技术的发展水平体现了社会的科学文明。摩天大楼的高度限制,不仅是建筑技术上的因素,一个重要的因素是受电梯提升高度的限制。相信,随着电梯技术的开发研究,高效、高速、智能化控制的电梯一定会提供优质良好的服务。无机房、无齿轮、电磁兼容性、远程监控等技术将是电梯工业今后几年的重要研究方向。参考文献【1】 濮良贵，纪名刚.机械设计.7版.北京：高等教育出版社，2001.【2】 汝元功，唐照民.机械设计手册.北京：高等教育出版社，1995.【3】 成大先.机械设计图册.北京：化学工业出版社，2000.【4】 孙恒，陈作模主编.机械原理.北京：高等教育出版社，1997.【5】 走昏君主编.机械原理课程设计手册.北京：高等教育出版社，1998.【6】 李奇涵主编.冲压成型工艺与模具设计.北京：科学出版社.2007.【7】 王振德，石溪，吴昊等. 现代科技百科全书.广西：广西师范大学出版社，2006.【8】 史信芳. 电梯选用指南.华南理工大学出版社.2003.【9】 刘爱国,郭宏毅,陈剑峰等. 电梯安装与维修实用技术. 河南科学技术出版社.2008.【10】 金晴川. 电梯与自动扶梯技术词典. 上海交通大学出版社.2005【11】 郑大勇. 建筑电气、电梯与智能建筑工程质量监控与通病防治图表对照手册. 中国电力出版社.2005.【12】 刘新宇. 电梯工程施工监理实用手册. 中国电力出版社.2005.【13】 刘爱国,朱红民,郭宏毅. 电梯故障排除实例. 河南科学技术出版社.2008.【14】 GB75881995电梯制造与安装安全规范【15】 GB75881995电梯制造与安装安全规范 黄河科技学院毕业设计 第 23 页 毕业设计(论文)文献翻译 院（系）名称工学院机械系 专业名称机械设计制造及其自动化 学生姓名 指导教师 2012年 03 月 10 日ELEVATOR SAFETY: GIVE THE MINER A BRAKEABSTRACTOver a five-year period, there were at least 18 documented cases of ascending elevators striking the overhead. In some cases, the accidents resulted in serious injuries or fatalities. These accidents occurred on counter weighted elevators as a result of electrical, mechanical, and structural failures. Elevator cars are fitted with safeties that grip the guide rails and stop a falling car; however, these devices do not provide protection in the upward direction.Rules and regulations applying to elevator safety have come under review in response to these accidents. Some governing authorities have already revised their regulations to require ascending car over speed protection. This paper will discuss basic elevator design, hazards, regulations, and emergency braking systems designed to provide ascending car over speed protection. In addition, a case-study report on a pneumatic rope brake system installed and tested on a mine elevator will be discussed.I NTRODUCT I ONElevators incorporate several safety features to prevent the car from crashing into the bottom of the shaft. Safeties installed on the car can prevent this type of accident from occurring when the machine brake fails or the wire ropes suspending the car break. However, the inherent design of the safeties render them inoperative in the ascending direction.In the upward direction, the machine brake is required to stop the cage Rive an emergency condition occurs. Under normal operation, the machine brake serves only as a parking braked to hold the cage at rest. However, when an emergency condition is detected, modern elevator control system designs rely solely on the machine brake to stop the car.In the United States mining industry, the accident history has proven that this is not the best control strategy 2, 3. These accidents occurred when the retarding effort of the drive motor was defeated when the mechanical brakes were inoperative. This allowed the counterweight to fall to the bottom of the shaft, causing the car to over speed and strike the head frame. The high-speed elevator crashes into the overhead structure caused extensive mechanical damage and potentially fatal injuries.ELEVATOR DES I GNA basic understanding of elevator operation is required in order to assess the safety hazards present and determine the accident prevent methods available. Figure 1 shows a complete view of a mine elevator.Fig.1 Mico ElevatorSUSPENSION riCPCSIn a typical elevator, the ear is raised and leered by six to eight motordriven wire ropes that are attached to the top of the car at one end, travel around a pair of sheaves, and are again attached to a counterweight at the other end.The counterweight adds accelerating force when the elevator car is ascending and provides a retarding effort when the car is descending so that less motor horsepower is required. The counterweight is a collection of metal weights that is equal to the weight of the car containing about 45% of its rated load. A set of chains are looped from the bottom of the counterweight to the underside of the car to help maintain balance by offsetting the weight of the suspension ropesGuide rails that run the length of the shaft keep the car and counterweight from swaying or twisting during their travel. Rollers are attached to the car and the counterweight to provide smooth travel along the guide rails.The traction to raise and lower the car comes from the friction of the wire ropes against the grooved sheaves. The main sheave is driven by an electric motor.Motor-generator (M-G) sets typically pro-vide to dc power for the drive motor. Newer systems use a static drive control. The elevator controls vary the motor s speed based on a set of feedback signals that indicate the car s position in the shaft way. As the car approaches its destination, a switch near the landing signals the controls to stop the car at floor level. Additional shaft way limit switches are installed to monitor over travel conditions.The worst fear of litany passengers is that the elevator will go out of control and fall through space until it smashes into the bottom of the shaft. There are several safety features in modern elevators to prevent this from occurring. The first is the high-strength wire ropes themselves. Each 0. 625-in-diameter extra-high-strength wire rope can support 32, 000 lb, or about twice the average weight of a mine elevator filled with 20 passengers. For safety s sake and to reduce wear, each car has six to eight of these cables. In addition, elevators have buffers installed at the shaft bottom that can stop the car without killing its passengers if they are struck at the normal speed of the elevatorAs previously discussed, modern elevators have several speed control features. If they do not work, the controls will disconnect the motor and apply the machine brake. Finally, the elevator itself is equipped with safeties mounted underneath the car. If the car surpasses the rated speed by 15 to 25%, the governor will trip, and the safeties will grip the guide rails and stop the car. This was the invention that made elevator transportation acceptable for the general public.SAFETY HAZARDSA historical perspective of elevator development can account for today s problems with elevator safety rules and regulations 4. In the beginning of modern elevator history, it was realized that although there were several factors of safety in the suspension rope design, the quality of construction and periodic inspection could not be assured. Therefore, the elevator car was equipped with reliable stand by safeties that would stop the car safely if the suspension ropes failed. In 1853, Elisha. Otis, a New York mechanic, designed and demonstrated an instantaneous safety capable of safely stopping a free falling car. This addressed the hazard shown in figure 2.Later on, it was realized that passengers may be injured when the car over speeds in the down direction with suspension ropes intact, as shown in figure 3. To prevent this hazard, an over speed governor with gradually applied safeties was developed. It detected the over peeling condition and activated the safeties.Furthermore, it was noticed that frequent application of safetiescaused mechanical stress on the elevator structure and safety system. Therefore, a governor over speed switch was installed that would try to stop the car by machine brake before the safeties activated. The switch was a useful idea because it could also initiate stopping in the case of over speeding in the up direction as well.The problem started in the 1920s when the American Elevator Safety Code was developed. The writers most likely looked at the technology that was available at that time and subsequently required it on all elevators covered by the Code.The writers were so concentrated on describing the design of the required devices that they forgot to acknowledge the hazards that the devices are guarding against and the elevator components that may failand cause the hazards. They did not consider the fact that for 90% of the elevator trips, the elevator is partially loaded (i. e. less than 45% of rated load) 5. Therefore, if a brake failure occurs, the elevator will over speed and crash in the up direction as shown in figure 4.Fig.4 Car over speed UPUntil recently, elevator safety systems have not differed significantly from the early 1900 s designs. The problem arises because rule rnakeing committees and regulatory authorities are reluctant to require new safeguards when the technology has not been fully developed. Conversely, the elevator manufacturing industry cannot justify the product development expense for a new safety device with little marketability. This problem will be addressed in the following sectionsRULES AND REGULATIONSSeveral rulemaking committees and government safety authorities have addressed the deficiencies in the existing elevator regulations and have proposed revisions to the elevator safety codes.The report from the American Society of Mechanical Engineers A17 Mechanical Design Committee on Cars ascending into the building overhead, -dated September 1987, contained the types of failures that could result in elevators accelerating into overhead structure and an analysis of the possible solutions. In addition, a proposal to the A17. 1 Committee for a new code Rule 205. 6 was introduced as follows:Rule 205. 6 (Prevention of over speeding car from striking the overhead structure) : All traction elevators shall be provided with a means to prevent an ascending car from striking the overhead structure. This rneans shall conform to the following requirements:1.Prior to the time when the counterweight strikes its buffer, it shall reduce the speed of the car to the speed for which the counterweight buffer is designed.2.It shall not develop an average retardation of the car in excess of 32.2 ft /s2 (9.81 m/s2) during the stopping phase.3.1t shall be a mechanical means independent of the driving machine brake.4.1t shall prevent over speeding of the elevator system through the control of one or more of the followinga. counterweightb. carc. suspension or compensating rope system.This proposed rule is currently under committee review, and consideration has been given to requiring protection to prevent the car from leaving the landing with the doors opened or unlocked.Pennsylvania Bureau of Deep Mine SafetyAn ascending elevator car accident occurred at a western Pennsylvania coal mine on February 4, 1987 and caused extensive structural damage and disabled the elevator for two months. Following this accident, the Pennsylvania. Bureau of Deep Mine Safety established an advisory committee to determine these devices that are available to provide ascending car over speed protection for new and existing mine elevator installations.The following four protective methods were determined to be feasible based on engineering principles or extensive mine testing.1.Weight balancing (counterweight equals the empty car weight)2.Counterweight safeties3.Dynamic braking4.Rope brakeThe Pennsylvania Bureau of Deep Mine Safety has approved these four methods and has made ascending car over speed protection mandatory on all existing counterweighted mine elevators.Dynamic BrakingA second solution used in the United States mining industry is the application of passive dynamic braking to the elevator drive motor 6. As mentioned earlier, most elevators use direct current drive motors that can perform as generators when lowering an overhauling load. Dynamic braking simply connects a resistive load across the motor armature to dissipate the electrical energy generated by the falling counterweight. The dynamic braking control can he designed to function when the main power is interrupted. Dynamic braking does not stop the elevator but limits the runaway speed in either direction; therefore, the buffers can safely stop the conveyance. Rope BrakeA pneumatic rope brake that grips the suspension ropes and stops the elevator during emergency conditions has been developed by Bode Aufzugel 7. This rope brake has been used in the Netherlands since August 12, 1957.Case Study: Rope Brake Testing and EvaluatioThe first pneumatic rope brake was installed in the United States at a western Pennsylvania coal mine on September 8, 1989. The largest capacity Bode rope brake (model 580) was installed on this coal mine elevator. This rope brake installation was tested extensively by Mine Safety and Health Administration engineers from the Pittsburgh Safety and Health Technology Center. A summary of the findings will be presented in this study.FunctionThe rope brake is a safety device to guard against over speed in the upward and downward directions and to provide protection for uncontrolled elevator car movementsThe rope brake is activated when the normal running speed is exceeded by 15%as a result of a mechanical drive, motor control system, or machine brake failure. The rope brake does not guard against free fall as a result of a break in the suspension ropes.Standstill of the elevator car is also monitored by the rope brake system. If the elevator car moves more than 2 to 8 inches in either direction when the doors are open or not locked, the rope brake is activated and the control circuit interrupted. The rope brake control must be manually reset to restore normal operation.The rope brake also provides jammed conveyance protection for elevators and friction driven hoists. If the elevator car does not move when the drive sheave is turning, the rope brake will set, and the elevator control circuit will be interrupted.The rope brake control contains self-monitoring features. The rope brake is activated if a signal is not received from the pulse tachometer when the drive is runningThe rope brake requires electrical power and air pressure to function properly. The rope brake sets if the control power is interrupted. When the power is restored, the rope brake will automatically release.Typically, elevator braking systems are spring applied and electrically release. Therefore, no external energy source is needed to set the brake. The rope brake requires stored pressurized air to set the brake and stop the elevator. Therefore, monitoring of the air pressure is essential. If the working air pressure falls below a preset minimum, the motor armature current is interrupted, and the machine brake is set. When the air pressure is restored, the fault string is reset.Pneumatic DesignThe rope brake system is shown in figure 5. Starting from the air compressor tank, the pressurized air passes through a water separator and manual shut off valve to a check valve. The check valve was required to ensure the rope brake remains set even if an air leak develops in the compressed air supply. A pressure switch monitors for low air pressure at this point and will set the machine brake as mentioned earlier. The air supply is split after the check valve and goes to two independent magnetic two-way valves. The air supply is shut off (port A), while the magnetic valve coil is energized. When the magnetic valve coil is reenergized, the air supply is directed to the B port, which is open to the rope brake cylinder. The air pushes the piston inside the rope brake cylinder and forces a movable brake pad toward a stationary brake pad. The suspension ropes are clamped between the two brake pads. The rope brake is released by energizing the magnetic valve, which vents the pressurized rope brake cylinder to the atmosphere through a blowout silencer on port S.The force exerted on the suspension ropes equals the air pressure multiplied by the surface area of the piston. The rope brake model number 580 designates the diameters of the brake cylinder in millimeters. This translates into 409. :36 in of surface area. The working air pressure varies from 90 to 120 lbf/in2. The corresponding range of force applied to the suspension ropes is 36, 842 to 49, 123 lb. The force experienced by the ropes as they pass over the drive sheave under fully loaded conditions is about 34, 775 lb. Therefore, the ropes experience a 6 to 41% greater force during emergency conditions than normally encountered during full load operation.Mechanical ModificationsPrior to testing, several mechanical modifications were required to protect the rope brake system from environmental and mechanical damage. The modifications also reduced the possibility and the undesirable effect of an air leak in the pneumatic system. The following modifications were included in the rope brake design:1.The 200 lbf/in2 rated plastic air hose was replaced with 2, 000 lbflin2 rated metal braided hose with integral couplings.2.The air hose compression fittings were replaced by stainlesssteel threaded connectors.3.All the electrical components were installed in protectiveenclosures, and the wiring was installed in conduit.4. A check valve was installed in the compressed air supply line to hold the rope in the applied position once it was set even if air pressure was lost in the air compressor tank.5. The added check valve required an additional pressure switch to monitor the supply air pressure. The original pressure switch would not detect a. pressure loss in the air compressor tank when the check valve was installed. The contacts of the two pressure switches were installed in series.Mechanical TestingTests were conducted to determine if the rope brake would operate reliably in the mining environment to provide ascending car over speed protection.First, accelerated mechanical testing was performed to determine if the braking system could withstand repeated operation without experiencing significant wear or failure. These tests were performed while the suspension ropes were stationary. This testing was conducted at both the mine site installation and in the laboratory.Mine site testing was conducted every 4 hr. Mechanical counters were installed on both the machine brake and the rope brake to record the total number of operations for each brake. Every 4 hr, the number of times the machine brake had set during the previous 4 hr period was noted, and then, the rope brake was operated an equal number of times.The mechanical testing concluded after 30 days of around the clock testing. The total number of rope brake operations was 3430. The temperature range varied from 25 to 83.One of the rope brake components subjected to wear was the piston ring gasket. This gasket provides the air seal between the moving piston, which presses against the traveling brake pad, and the stationary cylinder. An overload test was conducted to determine theintegrity of this seal.For the test, 8750 lb (125% of rated load) was loaded onto the car at the bottom of the shaft. Then, the rope brake was set, and the machine brake was disengaged. The air pressure was released from the air compressor tank, and the air pressure inside the rope brake cylinder was monitored. The load was successfully held stationary for 1 hr. The initial air pressure was 114 lbflin2, and after 1 hr, the pressure was 102 lbflin2. The pressured reduction may be attributed to an air leak through the check valve or past the piston ring gasket as a result of wear.Laboratory mechanical tests were also performed on the rope brake in the Mine Electrical Systems Division laboratories located at. The Pittsburgh Safety and Health Technology Center. The testing was performed on the smaller Bode rope brake model 200. The rope brake system was positioned outside the laboratory building under an awning that allowed the brake system to be exposed to the outside air temperature and humidity but was protected from direct contact with the rain and snow. The rope brake was activated remotely by computer control. The computer was programmed to apply and then release the rope brake every 38 s and log the number of operations. The outside air temperature, relative humidity, and barometric pressure were also continuously recorded.After 2 mo of testing and 146, 836 operations, the rope brake was disassembled and inspected for wear. The pneumatic. piston ring gasket exhibited minimal wear. Superficial rust was evident where the compressed air entered the rope brake and displaced the lubricant.Over the 70 days of testing, the temperature ranged from 5 to 82, and the relative humidity varied from 25 to 100%. At times, thick accumulations of frost build up on the air line between the magnetic valve and the rope brake cylinder. Therefore, the formation of ice inside the compressed air lines was possible; however, no adverse affects were observed. Rope Brake Control Failure AnalysisIn addition to the previously discussed mechanical analysis, testing and evaluation of the rope brake electrical control system was conducted. Brake control system studies were performed at the mine site and in the laboratory. The safety evaluation was conducted to ensure that a single undetected failure would not defeat the protection provided by the rope brake.Component failure should be detected by the brake control system and cause the elevator to stop safely and remain at rest until the failure is corrected. If automatic detection was not feasible, the periodic inspection and maintenance procedures were required to specify detailed testing of the possible failed component.The rope brake control system, which is shown in figure 6, monitors the following four inputs: NI contactor, speed relay, pressure switch, and the rope pulse tachometer. Based on this input information, the brake logic decides to set the machine brake or both the machine brake and the rope brake. A test board was designed and built to simulate the brake control inputs with toggle switches and to provide relay coil loads for the brake logic output. A separate power source supplied 24 V do to the simulator board and brake control box. Evaluation of this simulation board provided the following information on the function of each input.中文翻译电梯安全：给矿工刹车摘要在五年期间，至少有18起上升电梯撞毁高架建筑物的案例。在某些情况下，造成重伤或死亡事故。这些事故发生在电梯对重装置因电气、机械、结构的不合格。电梯轿厢通过紧夹导轨得到适当的保护，阻止轿厢坠落；不过， 这种装置不提供方向向上的保护。适用于电梯安全的法规己经针对这些事故进行审查。一些主管单位己修 订的条例规定上升轿厢的超速保护。这份文件将讨论基本电梯设计、灾害、 法规和制度，以提供紧急制动系统给向上轿厢的超速保护。此外，个案研究报 告的气压绳索制动系统的安装和测试煤矿电梯将会被讨论。绪论电梯安装了几个安全保险装置，以防止轿厢坠入井道底部。当机械制动 失败或悬挂轿厢的绳线断裂时,安装在轿厢上的保险装置可以防止这类事故 的发生。然而，固有的保险装置的设计在向上方向上是不起作用的。向上的方向上，当出现紧急情况时，机械制动必须制止轿厢运行。在正 常运转情况下，机械制动系统只能作为停车的闸来控制轿厢保持静止。然而， 紧急状况发生时，现代电梯控制系统设计单靠机械制动来制止轿厢的运行。在美国采矿业，事故历史已经证明这不是最好的控制策略。当机械刹车失效，当驱动发电机的减速效力失败时，事故就发生了。这使得对重装置坠 入井道的底端，造成轿厢超速运行并且击毁井架。高速电梯坠入高架建筑物 造成严重的机械破坏，和潜在的致命性的伤害。电梯设计了解电梯运行基本要求，以评估目前的安全威胁，并确定事故预防的有效方法。图1显示了一个完整的矿井电梯示意图。图1 矿井电梯在典型的电梯中，轿厢的升降是由六到八条由电机驱动的钢索牵引的。 这些钢索的一端附在轿厢顶部，围绕一对滑轮运转，而另一端则附在对重装 置上。当轿厢上升时，对重装置提供用以加速的动力，而当轿厢下降时，对重 装置则提供延缓作用，以减少所需的电机马力。对重是对金属重量的一种采 集，它的量等于包含45%的额定负载的轿厢的重量。一组链通过偏置悬吊锁 的重量，从对轿厢的底部到轿厢的下侧构成环状以帮助维持轿厢的平衡。 当轿厢和对重装置运行时，井道的导轨用以防止它们摆动。附在轿厢和对重装置上的滚轮则是保证它们沿导轨平稳运行的。轿厢升降的牵引力来自于钢索对滑轮的摩擦力，而主滑轮是由电机驱动的。大多数电梯是使用直流电机的，因为它的转速可以被精确地控制己满足 轿厢的平稳的加速或减速的要求。电动发电机装置为驱动电机提供直流电 力。较新型的系统都使用静态驱动控制，通过表示轿厢在井道中的位置的反 馈信号，电梯控制可以改变电机的转速。当轿厢接近目的地楼层时，靠近层 站的幵关就会发出控制信号使轿厢停在相应层上。首先就是高强度钢索本身，每根直径为0.625英寸的钢索可以负担 32000磅的重量，或者一部乘载20名乘客的矿井电梯的重量的两倍。为了 安全和减小磨损，每个轿厢都配有6到8条电缆。此外，精到的底部还装有 缓冲器，以防电梯故障时造成乘客的损伤。正如先前讨论的，现代电梯有许多速度控制方法。当它们出现故障时， 这些控制可以切断与电动机的联系并使电梯刹住。最后，电梯本身也备有安 全钳，如果轿厢速率超过额定速率15到25，安全钳便会夹紧导轨使轿厢 停住。这个发明使得电梯这一运送工具被普遍地应用于社会。安全威胁一次电梯发展的过程中的预言可以解释今天电梯的安全规则。当现代电 梯刚幵始发展时，人们就意识到尽管在悬吊绳索中设有安全钳，但建筑物的 质量和定期的检验无法保证。因此，电梯轿厢需要装备一种可以在悬索失效 时仍能安全地停止轿厢的装置。1853年，一位名叫伊利沙奥蒂斯的纽约机 械师，设计并示范了一种能够及时停止轿厢下落的装置。这种危险如图2 所示。图2 悬吊故障稍后，人们意识到即使悬索完整无缺，当轿厢下降时，乘客也可能会受伤，如图3所示。为了防止这种危害一种带有逐步式安全钳的限速器被设计出来。它可以检测到超速情况并激活安全措施。图3 轿厢超速下降此外，还注意到安全前的频繁使用会引起电梯结构和安全系统的机械压 力。因此，安装了一种限速器超速开关，它可以在安全钳使用前通过机械制 动停止轿厢。这种开关非常有用，因为在轿厢超速上升时它也可以发挥作用。问题出现于二十世纪二十年代，当时美国电梯安全代码己经发展起来。 作者很可能出于对当时可行的技术和后来的需要，因此将所有电梯都设置了 这种代码保护。作者们如此将注意集中在所需设备的设计描述上以至于忽略了这些设 备所预防的危险以及电梯的部件有可能发生故障从而导致危险。他们没有考 虑到这个90的电梯在不满载时(例如负载小于额定值的45时的运行中都 会发生的事实。因此，如果制动故障发生，电梯将会超速上升，如图4所示。图4 轿厢超速上升直到最近，自1900年初设计的电梯安全系统还没有很大差别。这个问题 的产生是因为在安全体系技术没有被完全改进的情况下，规则委员和权威人 士难以去要求新的安全措施。反过来说，电梯制造产业投入到没有市场的新 安全设备的发展费用很少。这个问题将在以下各节讨论。 法规安全规则委员会和一些政府机关的安全权威指出了现行电梯规则的缺 陷，并提议对电梯安全规则进行修订。该报告来自美国机械工程师学会-八17机械设计委员会关于轿
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