METHODOLOGY OF THE CAM MECHANISM DESIGN OF ROTARY RAKES

This paper describes the method of derivation of mathematical description of a cam orbit in rotary rakes (hay aggregators). At fi rst, the authors describe basic construction elements of the rotary hay rake mechanism and their mutual links and relationships. Therea er, they defi ne the origin and the orientation of the system of coordinates, in which all calculations are carried out. In the next step they defi ne basic requirements concerning the assurance of an optimum functioning of cam mechanisms as well as their transformation into mathematical equations. These requirements represent a base for the mathematical formulation of an optimum transition curve and it is emphasized that an optimum formulation of parameters of this curve is very important. In the course of calculation, they use also a normalized transition curve, which is used for the optimizations of the total number of parameters of the transition curve. Therea er, they take into account mechanical and operational parameters of the hay aggregators and convert the optimum transition curve to that part of the space curve, which agrees at best with these parameters. Finally, the whole cam orbit is constructed using individual segments and presented as a sequentially defi ned space curve. Its individual parts concur sequentially to the level of the second derivation and are described as explicit mathematical functions of mechanical and operational parameters of the hay aggregator. The defi nition of the system of coordinates, the execution phase of calculations and the fi nal shape of the cam orbit are illustrated in graphs.