Department of Mechanical Engineering, National Institute of Technology, Silchar-788010, India.
*Corresponding Author.
NotationOAPBC
the complete four bar mechanism
Pcoupler point
acrank
dground link
bcoupler link rocker
elength of one of the sides of the ternary link
flength of the line joining A and C
θangle between the a and d
βthe coupler angle
γangle made by the link b with the hz. line passes through the point A
RA,RPposition vector of the point A, P
RPAthe relative position of point P w.r.t point A
VAVelocity of point A
VPVelocity of point P
VPAVelocity of point P w.r.t point A
AAAcceleration of the point A
APAcceleration of the point P
APAAcceleration of the point P w.r.t point A
α1Acceleration of the crank
α2Acceleration of the coupler
α3Acceleration of the rocker
φangle made by the line joining point A and C with the horizontal line passes through the point A.
F12force acting on link 1 due to link 2.
F32force acting on link 3 due to link 2.
F43force acting on link 4 due to link 3.
F14force acting on link 1 due to link 4.
T12torque on link 1 due to link 2.
R12relative position of link 2 w.r.t link 1
R32relative position of link 3 w.r.t link 2.
R34relative position of link 4 w.r.t link 3.
R14relative position of link 4 w.r.t link 1.
Computer programme and Genetic algorithm is used in analysis and synthesis of a planar four-bar mechanism. Link dimensions were varied to obtain coupler path maps. Position, velocity, acceleration and the force at the coupler point at various input angles were obtained and the designed path is utilized in the working models. Plot of variation of the link angles, variation of velocity and acceleration of the coupler point with the crank angle is obtained. It is found that ratio of velocity of crank and coupler point varies between 4.48 and 0.38, acceleration of the coupler point is maximum. The four bar mechanism can be used to transfer small jobs at regular interval of time. With addition of another four bar mechanism with this, a papad making machine is shown as an useful application.
coupler curves, coupler point, Grashof's law, four bar mechanism
