《機(jī)械專業(yè)英語(yǔ)》課件第17章

Unit17TEXT

LEARNTOSPEAKNEWWORDSANDEXPRESSIONSNOTES

EXERCISES

READINGMATERIALPROFESSIONALWORDSANDPHRASES Lathe Alatheisamachinetoolforcuttingmetalfromthesurfaceofaroundworkfastenedbetweenthetwolathecentersandturningarounditsaxis.Inturningtheworkacuttermovesinthedirectionparalleltotheaxisofrotationoftheworkoratanangletothisaxis,cuttingoffthemetalfromthesurfaceofthework.Thismovementofthecutteriscalledthefeed.Thecutterisclampedinthetoolpostwhichismountedonthecarriage.Thecarriageisthemechanismfeedingthecutterintheneededdirection.Thelathehandmayfeedthecutterbyhandormaymakeitbefedautomaticallybymeansofspecialgears.

Thelargestpartofthelatheiscalledthebedonwhichtheheadstockandthetailstockarefastenedatoppositeends.Ontheupperpartofthebedtherearespecialwaysuponwhichthecarriageandthetailstockslide.

Thetwolathecentersaremountedintwospindles:one(thelivecenter)isheldintheheadstockspindle,whiletheother(thedeadcenter)inthetailstockspindle.Fig.17-1Anenginelathe

Thelathechuckisusedforchuckingthework,whichisforclampingitsothatitwillrotatewithoutwobblingwhileturning.Thechuck,usually,mountedontheheadstockspindle,mayhavedifferentsizesandconstruction.Iftheworkisperfectlyround,itmaybechuckedintheso-calledthree-jawuniversalchuck,allthejawsofwhicharemovedtothecenterbyturningthescrew.Butiftheworkisnotperfectlyround,thefour-jawindependentchuckshouldbeused.

Inturningdifferentmaterialsandworksofdifferentdiameters,lathesmustberunatdifferentspeeds.Thegearboxcontainedintheheadstockmakesitpossibletorunthelatheatvariousspeeds.

Beforeturningaworkinthelathe,thelathecentersaretobealigned;thatmeansthattheaxesofbothcentersmustbeononeline.

Thealignmentofthelathecentersmaybetestedbytakingacutandthenmeasuringbothendsofthecutwithamicrometer.Notallworksshouldbefastenedbetweenthetwocentersofthelathe.Ashortworkmaybeturnedwithoutusingthedeadcenter,bysimplychuckingitproperlyatthespindleoftheheadstock.

LEARNTOSPEAKMr.Li: Excuseme,mayIaskyouaquestion?Bob.Bob: Ofcourse!Mr.Li: Doyouknowaboutthestructureofthelathe?Bob: Yes.Iknowsomeofthem.Mr.Li: What’sthis?Bob: It’saheadstock.Sometimespeoplecallitastheheartofalathe.Mr.Li: What’sthisthen?Bob: It’sachuckandawork-piececanbemountedonit.Mr.Li: What’sthat?Bob: It’stoolpostandcarriage.Thecuttingtoolsareputhere.Mr.Li: What’sthat?Bob: It’scenterandtailstock.Mr.Li:What’sthat?Bob: It’sabed.Theseareallthemainstructureofthelathe.Arethosecleartoyou?Mr.Li:Yes.Youareverykind.Bob: Delightedtohavebeenofassistance.machinetool 機(jī)床，工具機(jī)millingmachine 銑床toolpost 刀座，刀架livecenter 主軸頂尖deadcenter 尾架頂尖

NOTES

1．Inturningtheworkacuttermovesinthedirectionparalleltotheaxisofrotationoftheworkoratanangletothisaxis,cuttingoffthemetalfromthesurfaceofthework.車削工件時(shí)，車刀沿著工件的旋轉(zhuǎn)軸線平行移動(dòng)或者是與工件的旋轉(zhuǎn)軸線成一斜角移動(dòng)，將工件表面的金屬切除。

“parallel”為形容詞，“paralleltotheaxisofrotationofwork”做后置定語(yǔ)修飾名詞“direction”。

“cuttingoffthemetalfromthesurfaceofthework”為分詞短語(yǔ)作狀語(yǔ)，表示伴隨情況。這種狀語(yǔ)往往放在句末，常用逗號(hào)與句子的其它成分隔開(kāi)。

2．Thelathehandmayfeedthecutterbyhandormaymakeitbefedautomaticallybymeansofspecialgears.用手操縱手柄來(lái)使車刀實(shí)現(xiàn)進(jìn)給，也可以借助于專門的傳動(dòng)裝置實(shí)現(xiàn)自動(dòng)進(jìn)給。

有些動(dòng)詞如“make”、“hear”、“l(fā)et”、“watch”后的不定式作賓語(yǔ)補(bǔ)語(yǔ)時(shí)，可不帶不定式符號(hào)“to”。句中“befed”是不定式的被動(dòng)式，作賓語(yǔ)it的補(bǔ)語(yǔ)。由于其謂語(yǔ)動(dòng)詞是“make”，故省略不定式符號(hào)“to”，而成為“…makeitbefed…”。這里“it”代表“thecutter”。

句中“thelathehand”為主語(yǔ)，帶有兩個(gè)并列的謂語(yǔ)“mayfed”和“maymake”。

3．Thegearboxcontainedintheheadstockmakesitpossibletorunthelatheatvariousspeeds.裝入床頭箱內(nèi)的齒輪系統(tǒng)能使車床以不同的速度運(yùn)轉(zhuǎn)。

“it”在句中作形式賓語(yǔ)，而真正的賓語(yǔ)是不定式短語(yǔ)“torunthelatheatvariousspeeds”。它通常放在賓語(yǔ)補(bǔ)足語(yǔ)(possible)的后面。

“containedintheheadstock”作后置定語(yǔ)，修飾名詞“thegearbox”。

4．Beforeturningaworkinthelathe,thelathecentersaretobealigned;thatmeansthattheaxesofbothcentersmustbeononeline.車床在車削工件前，它的頂尖要對(duì)準(zhǔn)，即兩個(gè)頂尖的軸線必須在一條直線上。

句中有兩個(gè)“that”，前一個(gè)“that”是用作指示代詞，它代表前面句子的內(nèi)容，即代表“thelathecentersaretobealigned”。后一個(gè)“that”作連接詞，無(wú)詞義，引出賓語(yǔ)從句“…theaxesofbothcentersmustbeononeline”。

“tobealigned”是不定式的被動(dòng)式在句中作賓語(yǔ)。

EXERCISES1．DiscussthefollowingquestionsinEnglish:(1)?Whichpartsdoesanenginelatheconsistof?(2)?Howtomountthework-piecewhenturning?(3)?Howmanykindsofcuttingtoolsaretherewhenmachiningawork-pieceinthelathe?2．UseEnglishforreplacingChineseoruseChineseforreplacingEnglish.(1)車床的主軸(2)橫拖板的運(yùn)動(dòng)(3)尾架頂尖(4)?Thespeedofthemainspindle(5)?Rotatingofthefeedrod(6)?Railofbed

3．placea“T”aftersentencesthataretrueandan“F”afterthosethatarefalse.

(1)?Latheisthemachinetoolforholdingandturningmetal,plasticorothermaterialagainstacuttingtoolformacylindricalproduct.()

(2)?Iftheworkisnotperfectlyround,itmaybechuckedintheso-calledthree-jawuniversalchuck.()

(3)?Thelatheisoneofthemostimportantmachinesinamachineshop.()

(4)?Theheadstockwhichholdstheotherendofthework,movesalongthebed,andcanbeclampedinpositionatanypoint.()

(5)?Themostimportantofmachinetoolsusedinindustryarelathes,drillingmachines,andmillingmachines.()

(6)?Thesmallestpartofthelatheiscalledthebedonwhichtheheadstockandthetailstockarefastenedatoppositeends.()

4．Filltheblankswiththewordsandphrasesgivenbelow:springsandpulleys,gearsandpulleys,right,feeding,carrying,three-jaw,four-jaw,left,short,measurement,alignment,long.

(1)?Theheadstockismountedatthe_______endofthelathe.

(2)?Itcontainstheheadstockspindle,whichisrotatedbygearsorbyacombinationof________.

(3)?Butiftheworkisnotperfectlyround,the_________independentchuckshouldbeused.

(4)?Thecarriageisthemechanism________thecutterintheneededdirection.

(5)?The______ofthelathecentersmaybetestedbytakingacutandthenmeasuringbothendsofthecutwithamicrometer.

(6)?A________workmaybeturnedwithoutusingthedeadcenter,bysimplychuckingitproperlyatthespindleoftheheadstock.READINGMATERIAL

ThePlaner

Theplanerisoneofthebiggestmachinetoolsthatemployareciprocatingcuttingaction．Itgeneratesflatorcontouredsurfacesinaseriesofstraightcuts．Itsefficiencyishigherthanthatoftheshaper．

Theworkontheplanerisheldonthemachinetableandmovesunderthetoolwhichiscarriedontherail．Thebedmustbeapproximatelytwiceaslongasthetabletosupportitatallpositionsduringthestroke．Thedouble-housingplanerhastwohousingstosupporttherailateachend．Theopen-sideplanerhasthehousing