《机械专业英语》课件第17章.ppt

1、Unit 17TEXT LEARN TO SPEAK NEW WORDS AND EXPRESSIONS NOTES EXERCISES READING MATERIAL PROFESSIONAL WORDS AND PHRASES LatheA lathe is a machine tool for cutting metal from the surface of a round work fastened between the two lathe centers and turning around its axis.In turning the work a cutter moves

2、 in the direction parallel to the axis of rotation of the work or at an angle to this axis,cutting off the metal from the surface of the work.This movement of the cutter is called the feed.The cutter is clamped in the tool post which is mounted on the carriage.The carriage is the mechanism feeding t

3、he cutter in the needed direction.The lathe hand may feed the cutter by hand or may make it be fed automatically by means of special gears.The largest part of the lathe is called the bed on which the headstock and the tailstock are fastened at opposite ends.On the upper part of the bed there are spe

4、cial ways upon which the carriage and the tailstock slide.The two lathe centers are mounted in two spindles:one(the live center)is held in the headstock spindle,while the other(the dead center)in the tailstock spindle.Fig.17-1 An engine latheThe lathe chuck is used for chucking the work,which is for

5、 clamping it so that it will rotate without wobbling while turning.The chuck,usually,mounted on the headstock spindle,may have different sizes and construction.If the work is perfectly round,it may be chucked in the so-called three-jaw universal chuck,all the jaws of which are moved to the center by

6、 turning the screw.But if the work is not perfectly round,the four-jaw independent chuck should be used.In turning different materials and works of different diameters,lathes must be run at different speeds.The gearbox contained in the headstock makes it possible to run the lathe at various speeds.B

7、efore turning a work in the lathe,the lathe centers are to be aligned;that means that the axes of both centers must be on one line.The alignment of the lathe centers may be tested by taking a cut and then measuring both ends of the cut with a micrometer.Not all works should be fastened between the t

8、wo centers of the lathe.A short work may be turned without using the dead center,by simply chucking it properly at the spindle of the headstock.LEARN TO SPEAKMr.Li:Excuse me,may I ask you a question?Bob.Bob:Of course!Mr.Li:Do you know about the structure of the lathe?Bob:Yes.I know some of them.Mr.L

9、i:Whats this?Bob:Its a headstock.Sometimes people call it as the heart of a lathe.Mr.Li:Whats this then?Bob:Its a chuck and a work-piece can be mounted on it.Mr.Li:Whats that?Bob:Its tool post and carriage.The cutting tools are put here.Mr.Li:Whats that?Bob:Its center and tailstock.Mr.Li:Whats that?

10、Bob:Its a bed.These are all the main structure of the lathe.Are those clear to you?Mr.Li:Yes.You are very kind.Bob:Delighted to have been of assistance.NEW WORDS AND EXPRESSIONS drilling n.钻削 milling n.铣削 fasten v.(使)固定，加固，连接 feed n.&vt.进给，送给 cutter n.刀具 clamp n.夹子，夹具，夹钳 vt.夹住，夹紧 carriage n.溜板，拖板 be

11、d n.床，床身 headstock n.主轴箱 tailstock n.尾架，尾座，顶针座 slide v.(使)滑动，(使)滑行 n.滑动 metalwork n.金属制品，金属制造 spindle n.轴，主轴，连接轴 wobble vi.摇晃，摇摆 alignment n.队列，对准，同轴度 micrometer n.测微计，千分尺 machine tool 机床，工具机milling machine 铣床tool post 刀座，刀架 live center 主轴顶尖dead center 尾架顶尖 NOTES1In turning the work a cutter moves i

12、n the direction parallel to the axis of rotation of the work or at an angle to this axis,cutting off the metal from the surface of the work.车削工件时，车刀沿着工件的旋转轴线平行移动或者是与工件的旋转轴线成一斜角移动，将工件表面的金属切除。“parallel”为形容词，“parallel to the axis of rotation of work”做后置定语修饰名词“direction”。“cutting off the metal from the

13、surface of the work”为分词短语作状语，表示伴随情况。这种状语往往放在句末，常用逗号与句子的其它成分隔开。2The lathe hand may feed the cutter by hand or may make it be fed automatically by means of special gears.用手操纵手柄来使车刀实现进给，也可以借助于专门的传动装置实现自动进给。有些动词如“make”、“hear”、“let”、“watch”后的不定式作宾语补语时，可不带不定式符号“to”。句中“be fed”是不定式的被动式，作宾语it的补语。由于其谓语动词是“mak

14、e”，故省略不定式符号“to”，而成为“make it be fed”。这里“it”代表“the cutter”。句中“the lathe hand”为主语，带有两个并列的谓语“may fed”和“may make”。3The gear box contained in the headstock makes it possible to run the lathe at various speeds.装入床头箱内的齿轮系统能使车床以不同的速度运转。“it”在句中作形式宾语，而真正的宾语是不定式短语“to run the lathe at various speeds”。它通常放在宾语补足语(

15、possible)的后面。“contained in the headstock”作后置定语，修饰名词“the gearbox”。4Before turning a work in the lathe,the lathe centers are to be aligned;that means that the axes of both centers must be on one line.车床在车削工件前，它的顶尖要对准，即两个顶尖的轴线必须在一条直线上。句中有两个“that”，前一个“that”是用作指示代词，它代表前面句子的内容，即代表“the lathe centers are to

16、 be aligned”。后一个“that”作连接词，无词义，引出宾语从句“the axes of both centers must be on one line”。“to be aligned”是不定式的被动式在句中作宾语。EXERCISES1Discuss the following questions in English:(1)Which parts does an engine lathe consist of?(2)How to mount the work-piece when turning?(3)How many kinds of cutting tools are the

17、re when machining a work-piece in the lathe?2Use English for replacing Chinese or use Chinese for replacing English.(1)车床的主轴(2)横拖板的运动(3)尾架顶尖(4)The speed of the main spindle(5)Rotating of the feed rod(6)Rail of bed 3place a“T”after sentences that are true and an“F”after those that are false.(1)Lathe

18、is the machine tool for holding and turning metal,plastic or other material against a cutting tool form a cylindrical product.()(2)If the work is not perfectly round,it may be chucked in the so-called three-jaw universal chuck.()(3)The lathe is one of the most important machines in a machine shop.()

19、(4)The headstock which holds the other end of the work,moves along the bed,and can be clamped in position at any point.()(5)The most important of machine tools used in industry are lathes,drilling machines,and milling machines.()(6)The smallest part of the lathe is called the bed on which the headst

20、ock and the tailstock are fastened at opposite ends.()4Fill the blanks with the words and phrases given below:springs and pulleys,gears and pulleys,right,feeding,carrying,three-jaw,four-jaw,left,short,measurement,alignment,long.(1)The headstock is mounted at the_end of the lathe.(2)It contains the h

21、eadstock spindle,which is rotated by gears or by a combination of_.(3)But if the work is not perfectly round,the_independent chuck should be used.(4)The carriage is the mechanism_the cutter in the needed direction.(5)The_of the lathe centers may be tested by taking a cut and then measuring both ends

22、 of the cut with a micrometer.(6)A_work may be turned without using the dead center,by simply chucking it properly at the spindle of the headstock.READING MATERIALThe PlanerThe planer is one of the biggest machine tools that employ a reciprocating cutting actionIt generates flat or contoured surface

23、s in a series of straight cutsIts efficiency is higher than that of the shaper The work on the planer is held on the machine table and moves under the tool which is carried on the railThe bed must be approximately twice as long as the table to support it at all positions during the strokeThe double-

24、housing planer has two housings to support the rail at each endThe open-side planer has the housing on one side onlyOpen-side planers are designed for work-pieces which are so wide that they can pass between the housings of double-housing planersThe double-housing machine，however，offers greater rigi

25、dity Some of the work that was formerly done on the planer is now done on the planer-type milling machine since the former is not so efficient as the latter.However,there are still many jobs that can be carried out better and more economically on the planer than on any other machines.For example,ang

26、ular surfaces are often easier to machine on a planer.Planning is also most effective in the machining of long and narrow surfaces.In addition,the planer usually takes the important first cut on the rough forging or casting to establish a reference surface for subsequent machining.PROFESSIONAL WORDS

27、 AND PHRASES contour n.轮廓 v.仿形 straight adj.直的，直线的 rail n.轨，铁轨 housing n.套，壳，罩 rigidity n.刚性，硬度 former adj.从前的，以前的 formerly adv.以前，过去 latter adj.后面的 angular adj.有角的 narrow adj.狭窄的 reference n.参考，基准面 subsequent adj.后来的，并发的 subsequently adv.其后，接着 contoured surface 仿形面，围线曲面 straight cut 直线切割 double-housing planer 双立柱(臂)龙门刨床 open-side planer 单立柱(臂)龙门刨床 the former 前者 the latter 后者 angular surface 斜面 reference surface 基准面，参考面