Development of design theory on the tooth arrangement and the threshing drum for a large-sized and high-speed head-feeding combine

This study was intended to develop the design theory of the threshing unit for a large-sized and a high-speed head-feeding combine. It may be applied for various combining capacities with different cutting widths and forward speeds. Design factors in the theoretical development are: (1) dimensions of the threshing drum, (2) tooth approaching angle, (3) distance between the adjacent teeth on their spiral setting line, (4) number of spirals, and (5) total number of teeth on the drum. A computer simulation program was developed to predict the proper dimensions for the threshing drum and tooth arrangement. A simulation for the prospective combine with varied capacities was also demonstrated. The parameters analyzed in the developed design theory were shown to be consistent with those of existing combines.