The solution to the problem of forage procurement largely depends on the availability and technical characteristics of mowers and the perfection of their design. Therefore, it is necessary to modernize existing mowers and create new ones. In this order, first, a crank-and-rocker mechanism used in new cutting drive mechanism of a reciprocating mower is elaborate, and then by using, the vector closed contour method, the mathematical equations describing the main parameters, specially the forces, are defined. Therefore, to validate the obtained equations, the Kazakh Scientific Research Institute of Mechanization and Electrification of Agriculture carried out numerous field experiments. The proposed reciprocating mower with new crank-and-rocker cutting drive mechanism has the ability to work on uneven natural and seeded hayfields, ensuring a reduction in dynamic loads and high-quality execution of the technological process.