cam mechanisms

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1、GuilhermeLimaNickHolbertJoshOwensSamMusaAcammaybedefinedasamachineelementhavingacurvedoutlineoracurvedgroove,which,byitsoscillation,rotationorreciprocatingmotion,givesapredeterminedspecifiedmotiontoanotherelementcalledthefollower.KINEMATICDIAGRAMFORCAMMECHANISMThefirstcamdes

2、ignswerefoundinLeonardodaVinci’ssketchesinhisnotebookstitledCodexMadridI-II.Leonardodesignedcammechanismsascompactmechanicaldevicesthatcouldtransformrotarymotiontolinearmotion.CamhammerDesignedaround1497byLeonardodaVinci.Thehammerusesacamtoconvertrotarymotiontooscillatingmoti

3、on.FirstdesignsseenwerebyLeonardodaVinci(1452,1519),CodexMadridI.Camsareclassifiedinthreeways:Intermsoftheirshape,suchaswedge,radial,cylindrical,globoidal,conical,spherical,orthree-dimensional;Intermsofthefollowermotion,suchasdwell-rise-dwell(DRD),dwell-rise-return-dwell(DRR

4、D),orrise-return-rise(RRR);orIntermsofthefollowerconstraint,whichisaccomplishedbyeitherpositivedriveorspringload.Thefollowermovesinaplaneperpendiculartotheaxisofrotationofthecam.Mostusedtypeofcammechanism.ToysSafetypins/locksttp://www.technologystudent.com/cams/flat1.htm

5、Thefollowerhasarollerthatoperatesinagroovecutonthefaceofacylinder.Thefollowerthenoscillatesasitfollowsthepath.Thistypeofcamcanbeseeninsomeoldclockmechanismsandstillinmodernsewingmachines.Machinesthatperformrepetitivemovementsmayuseacylindercamprofile.Turnsacircularrotation

6、intoarockingmotion.BoomedduringtheIndustrialRevolution.•Clothmaking•Powerconversion•Speedregulation•Mechanicalcomputation•Typewriting•Machining.Changethelengthorangleoftherodstoachievedifferentmotions.BicyclesHeavyMachineryAfollowerdisplacementdiagramisagraphshowingdispla

7、cementofthefollowerplottedasafunctionoftime.Sincethecamusuallyrotatesatconstantangularvelocity,thet-axiscanbeconsiderastheθ-axis.Thefollowerdisplacementdiagramdeterminestheshapeofthecam.http://www.youtube.com/watch?v=KRnTXvjTeIAhttp://www.youtube.com/watch?v=9jGHAL5ZRkAht

8、tp://www.cs.cmu.edu/~rapidproto/mechanisms/chpt6.htmlhttp://