Types Of Mechanisms
MAE 342 – Dynamics of MachinesTypes of MechanismsClassification of Mechanisms bytype and mobilityMAE 342 – Dynamics of Machines2Planar, Spherical and Spatial Mechanisms Planar Mechanisms: all points on eachpart move only in.Image from Technische Universität Ilmenau.Images from Tiptop Industry Co., Ltd.Image from Northern Tool Equipment Catalog Co.1
MAE 342 – Dynamics of Machines3Planar, Spherical and Spatial Mechanisms Spherical Mechanisms: all points on eachpart move only in.Image from Maarten Steurbaut.Images from the Laboratory for the Analysis andSynthesis of Spatial Movement.Images from Laboratoire de robotique, Université Laval.MAE 342 – Dynamics of Machines4Planar, Spherical and Spatial Mechanisms Spatial Mechanisms: points on each partcan move in any direction in 3-dimensionalspace.Image from the Kinematic Models for Design DigitalLibrary, Cornell University.Image from www.robots.com.Image from SlikaImage from the Special Session on Computer AidedLinkage Synthesis, ASME DETC 2002.2
MAE 342 – Dynamics of Machines5Mobility Degrees of freedom (DOF) is:the number of independent controlsneeded to position a body. Mathematically itis the number of independent variablesneeded to specify the position of a body. A planar body has DOF.A spherical body has DOF.A spatial body has DOF.MAE 342 – Dynamics of Machines6Mobility Mobility is:the number of degrees of freedom of a mechanism. If the number of planar bodies is n (and there are no joints) themobility is .If one of the bodies is fixed, the mobility is .If the number of spatial bodies is n (and there are no joints) themobility is .If one of the bodies is fixed, the mobility is .3
MAE 342 – Dynamics of Machines7Mobility Each type of joint imposes a certain numberconstraints(i.e., takes away a certain number of DOFfrom mechanism):Planar MechanismvariablesType of JointDOFDOF removedRevolutePrismaticCamGearMAE 342 – Dynamics of Machines8MobilityFigure from Uicker et al., Theory of Machines and Mechanismsa)b)c)d)e)f)Revolute joint (R) – Circular motionPrismatic joint (P) – Rectilinear motionScrew joint (S) – Helical motionCylindrical joint (C) – Cylindrical motionSpherical joint (G) – Spherical motionFlat joint (F) – Planar motionFigure from Unigraphics on-line documentation.4
MAE 342 – Dynamics of Machines9MobilityType of JointSpatial MechanismDOFDOF SphericalFlat/PlanarMAE 342 – Dynamics of Machines10Mobility “Kutzbach Criteria” for mobility (m) of: planar mechanisms:m spatial mechanisms:m where:5
MAE 342 – Dynamics of Machines11Mobility In Kutzbach criteriaa)If m 0b)If m 0c)if m 0MAE 342 – Dynamics of Machines12Mobility What is the mobility in these examples?a)b)c)d)Figures from Uicker et al., Theory of Machines and Mechanisms, 20036
MAE 342 – Dynamics of Machines13Mobility What is the mobility in these examples?a)b)c)d)Figures from Uicker et al., Theory of Machines and Mechanisms, 2003MAE 342 – Dynamics of Machines14Mobility Exceptions to the rule! Certain geometric conditionsDifferent parts of a linkage can havedifferent mobilities.7
MAE 342 – Dynamics of Machines15Torfason’s Classification of Mechanisms Snap-Action MechanismsLinear ActuatorsFine AdjustmentsClamping MechanismsLocational DevicesRatchets and EscapementsIndexing MechanismsSwinging or Rocking MechanismsReciprocating MechanismsReversing MechanismsCouplings and ConnectorsStop, Pause, and Hesitation MechanismsCurve GeneratorsStraight-Line Generators MAE 342 – Dynamics of Machines16Kinematic Inversion You can pick different links to be thefixed link – this is “kinematic inversion”Figures from Uicker et al., Theory of Machines and Mechanisms, 20038
MAE 342 – Dynamics of Machines17Grashof’s Law In a four bar linkage, if you want to be ableto sit on one link and have some other linkrotate 360 relative to you, then: where:s is the length of:l is the length of:p, q are the lengths of:MAE 342 – Dynamics of Machines18Grashof’s LawFigures from Uicker et al., Theory of Machines and Mechanisms, 20039
8 MAE 342 –Dynamics of Machines 15 Torfason’s Classification of Mechanisms Snap-Action Mechanisms Linear Actuators Fine Adjustments Clamping Mechanisms Locational Devices Ratchets and Escapements Indexing Mechanisms Swinging or Rocking Mechanisms Reciprocating Mechanisms Reversing Mec
Traditional Conflict Resolution Mechanisms and Institutions Kariuki Muigua Abstract This paper discusses traditional conflict resolution mechanisms and institutions among African societies, and their relevance in Kenya today. With the constitutional and statutory recognition of these mechanisms as a vital aspect of the access to justice mechanisms in Kenya, it is important to revisit their .
A commitment to always closing the feedback loop. Summary boxes: beneficiary feedback mechanisms Below are three boxes that summarise key information about drivers for developing feedback mechanisms, examples of mechanisms, and factors affecting how far these mechanisms ar
UNIT 1 SIMPLE MECHANISMS Simple Mechanisms Structure 1.1 Introduction Objectives 1.2 Kinematics of Machines 1.3 Kinematic Link or an Element 1.4 Classification of Links 1.5 Degree of Freedom 1.6 Kinematic Pairs 1.7 Different Pairs 1.7.1 Types of Lower Pair 1.7.2 Higher Pair 1.7.3 Wrapping Pair 1.8 Kinematic Chains
mechanisms to function. Because, as known mechanisms are basis of all mechanic devices. Hence, different types of mechanisms are utilized resulting different types of window regulators. The reason for using different mechanism
MPLS PW OAM mechanisms are described next, and a brief look at existing layer 2 OAM mechanisms is provided. The article goes on to describe the relationship between end-to-end fault detection and the segment-based OAM mechanisms. MPLS PW An MPLS PW is the mechanism used to carry layer 2 traffic over MPLS. It is a point-to-point
DYNAMIC MODELS WITH THOSE OF REAL MECHANISMS, AND RULES OF DESIGN 151 8.1. Introduction 151 8.2. Comparison of the responses of the various dynamic models of cam mechanisms with those of real mechanisms 151 8.2.1. Four-degrees-of-freedom model 151 8.2.2. Damping 156 8.2.3. Follower
Con: Geneva mechanisms usually require the use of gear reduction. Con: due to the reduction and the use of a cam, Geneva mechanisms have more moving parts than a worm drive Pro: Geneva wheels are less expansive to fabricate than worm drives Con: Geneva mechanisms are limited in the number of discrete positions.
accounting purposes, and are rarely designed to have a voting equity class possessing the power to direct the activities of the entity, they are generally VIEs. The investments or other interests that will absorb portions of a VIE’s expected losses or receive portions of its expected residual returns are called variable interests. In February 2015, the Financial Accounting Standards Board .
