Meshing Analysis of the Planetary Indexing Cam Mechanisms

Abstract

The planetary indexing cam mechanism is a type of indexing cam mechanism that employs planetary transmission structure. The mechanism is unusual compared to other planar cam mechanisms for the self-intersection occurs inevitably on the pitch curve of the cam. This results in the loss of contacts between a few rollers and cam profile. This paper investigates the effects of such loss of contacts on the transmission by analyzing the meshing procedure of the mechanism. The number of the self-intersection points on the pitch curve is determined in terms of the rotary index of the continuous curve. The meshing procedure is analyzed in detail and the pressure angles are calculated. The effects of the design parameters on the meshing status are studied and illustrated. At the end, it is pointed out that loss of contacts will not hamper the rightness of motion transfer in the mechanism if the design parameters are well selected.

High-capacity stacking apparatus for thermoforming machine – Part I: Synthesis of intermittent mechanisms as stacker driving units

“…Traditional cam mechanisms can also provide an output link with periods of dwell, but the output link must have a return stroke, which may not be always acceptable, so indexing cam mechanism have become widely used, especially in automatic machinery. Researches have been done on their geometry design, 19,20 analysis, 21,22 and torque balancing. 23,24 Lever mechanisms have only first-order connections, which is why they can transfer significantly higher loads at higher operating speeds, and have significantly lower friction losses than Geneva and cam mechanisms.…”

Effects of the design parameters on the synthesis of Geneva mechanisms

“…More recently, the design and the machining of Geneva mechanisms with one single crank and curved slots, as well as, the kinematic and geometric analysis of pure-rolling indexing cam mechanisms for epicyclic trains, were proposed in previous works. 30 –34 In particular, an improved Geneva mechanism for optimal kinematic performance was proposed in Heidari et al. 35 This mechanical design makes use of a suitable fixed groove cam, which controls the radius of action of the driving pin.…”