Chemical Engineering - Apllied Mechanics

Joints and linkage - Part 2

Divided by topic

JOINTS and LINKAGES A. Vania Politecnico di Milano, Dept. of Mechanical Engineering, Milan, Italy APPLIED MECHANICS –Prof. Andrea VANIA JOINTS prismatic joint helical joint 2 spherical 2D plane on plane hinge (or pin joint)spherical 3D APPLIED MECHANICS –Prof. Andrea VANIA JOINTS prismatic joint helical joint 3 splined shafts hub prismatic joint basic thread terms internal thread external thread screw boltnut mating piece ridges or teeth APPLIED MECHANICS –Prof. Andrea VANIA JOINTS 4 free rotations free translations name degree of freedom sphere between parallel planes sphere in a cylinder cylinder between parallel planes spherical sphere in a cylinder with groove planar spherical with groove toric cylindrical cylindrical with groove rotoidal prismatic hinge (or pin joint) rigid joint pin joint in a bridge pillar joint APPLIED MECHANICS –Prof. Andrea VANIA FOUR-BAR LINKAGE 5 q s l p s + l < p + q s (a) Crank -rocker (b) Double -crank s + l < p + q s driver driver Four-bar linkage: shortest link s, longest link l, intermediate length links pand q APPLIED MECHANICS –Prof. Andrea VANIA FOUR-BAR LINKAGE 6 s + l < p + q s (c) Rocker -crank (d) Grashof Rocker-rocker (e) Non-Grashof Rocker-rocker (triple rocker) (f) Change-Point Mechanism in Toggle Configuration s + l = p + q s + l < p + q driver driver (full rotation of the coupler link is possible) s s + l < p + q APPLIED MECHANICS –Prof. Andrea VANIA LINKAGES 7 APPLIED MECHANICS –Prof. Andrea VANIA CRANK AND SLOTTED LINK 8 Configuration “a”Configuration “b” APPLIED MECHANICS –Prof. Andrea VANIA LINKAGE DOFs 9 Front loader shovel () 12 N3 1 2m CC = −− − 1: chassis 2: arm 3+4: hydraulic actuator 6+7: hydraulic actuator 9: shovel APPLIED MECHANICS –Prof. Andrea VANIA 10 “SCARA” ROBOTS SCARA robots Selective Compliance Assembly Robot Arm end effector (e.g. screwdriver)end effector (tongs) () 1 2 3 45 N6 1 5 4 3 2m C C C CC = −−−−−− APPLIED MECHANICS –Prof. Andrea VANIA 11