中国地质大学长城学院本科毕业设计外文资料翻译 系 别： 工程技术系 专 业： 机械设计制造及其自动化 姓 名： 王宁宁 学 号： 05211607 2015 年 4 月 1 日外文翻译原文Scissor lifeIn todays society rapid development, some companies in the process of work to help, you need to use lifting machine. Lifters began using the invention of the United States in 1925, development has been through a lot of changes and improvements, types and development to a lot of kinds, generally has the pillar type and scissors, the drive mode with mechanical drive, hydraulic transmission, pneumatic transmission, etc. This design is from the generation and development of lifting machine, and introduces the manufacturing process improvement, etc.The direction of the lifting machine design choiceNow we can see most of the lifting machine most fixed installation. Portable lifting machine but we also have several successful design, such as traction type lifting machine, shear fork lift machine, etc. The prominent nature of this type of lifting machine advantage is good flexibility, can open at any time to repair the field service, easy to use, which make full use of its advantages. Because now lifting machine more fixed, so we consider the development and use of portable lifting machine, this scissor lift machine is designed.Until now we have the potential of the lifting machine for the development and utilization of the many ways, but there is still a developing widely and use efficiency is not high enough. Lifting machine, however, is when is now one of the essential equipment of many industries, is also one of the indispensable accessories on many large machinery in the future, thus promote our better to study about the structure of it, to improve, so as to extend the service life of the equipment and improve the performance of equipment. So far, our countrys lifting machine manufacturing technology over, there have been some quality technology is more mature, yu shu to lifting device has also been widely used in various fields, for our countrys economic and social development has made irreplaceable contributions.The history of lifting machineLifting machine in the world already had 70 years of history. Production in the United States in 1925 the first car lifting machine, it is a kind of controlled by pneumatic lifting machine, single column due to the use of air pressure is low, and block; Using leather to seal at the same time, thus when compressed air driven bounce and serious instability. Until ten years later, in 1935 the single-column lifting machine is adopted in other parts of the outside of the United States.In 1966, a German company produced the first double column lifting machine, this is another breakthrough in the design of the lifting machine, but it was not until 1977 the lifting machine in other countries outside Germany. Now double column lifting machine in the market to occupy a strong position, its sales still continues to grow. It compared with the four pillars of elevator, has both advantages and disadvantages as well as, the following will make a brief description.We see the vast majority of the lifting machine adopt fixed installation. Before lifting the car must be on the lifting machine. In terms of portable lifting machine also has several successful design, such as scissors lifting machine, diamond frame lifting machine, etc. But this kind of lifting machine there are still two major issues, close to the car bottom is difficult; In the workshop mobile lifting machine difficult to overcome the obstacles on the ground. Mobility is, of course, this kind of the prominent advantages of lifting machine. Now fixed installation of single column and double column, four-column lifting machine has already been widely adopted in service field, and the portable lifting machine is relatively far less.Lifting machine design requirementsDesign before you determine the basic situation of product design, to develop basic scheme according to the design requirement. The following is a list of the design - the scissors hydraulic lifting platform of some basic requirements:1) overview of the host: it is mainly used for the repair and maintenance of the crane is of workshop maintenance personnel;2) main lifting and falling of lifting movement, speed is slow, small hydraulic impact;3) the maximum load of 0.3 tons, with double hydraulic cylinder control connection combination fork lever mechanism. Maximum lifting height 15 meters;4) movement stability and security needs better;5) artificial control operation, button start control lift;6) working environment requirement: should not be in the sand on the ground floor, plank brick plate and so on more than a solid ground, not in the ground of the slope or potholes, should not be operated in excessive cold outside;7) reliable performance, low cost, easy to mov