This paper deals with the dimensional synthesis and kinematic analysis of a six-link planar mechanism for automated carton flap closing of packaging lines. The mechanism is a combination of a slider-crank sub-chain and a rocker linkage, which converts the continuous motion of the crank into a 90° oscillating flapper motion. The constrained systematic screening approach involved evaluating the candidate link configurations for Grashof feasibility, assembly feasibility, transmission angle quality, dead-point clearance and output swing accuracy throughout the 360° crank cycle. The chosen configuration results in a minimum transmission angle of 46° and a dead point margin of 53mm and a full 90° sweep of the flapper. The GIM software performs the kinematic at 30 rpm and has a peak velocity of 1.3 m/s and peak acceleration of 4.5 m/s2 at flapper tip for moderate dynamic loading and gentle flap contact. The critical crank position (folding load 150N) was calculated by static FEA. The results validate the validity of the structure as the max von Mises stress of 103 MPa and minimum safety factor of 2.1 are acceptable. Mechanically simple and economical alternative to pneumatically and servo-electrically operated packaging systems for medium size RSC cartons from 30-60 cycles per minute.
Keywords
Carton Flap Closing, Dimensional Synthesis, Slider-Crank Mechanism, Four-Bar Linkage, Kinematic Analysis.