Corresponding Analysis of Controls and Related Devices in Farm Machinery (I)

On Starting and Stopping Manipulation of Tractors

Abstract

To find out the relations between the arrangements of control devices and convenience of manipulation, tractor-operators' motions at starting and stopping were investigated by non-weighted corresponding link analysis method. The motion-analysis charts (Table. 1) and the link-analysis charts (Fig. 1) were drawn up of each tractor. Forty-four tractors in Table 2 were used as samples.
(1) The total frequency of link ranges from thirty-five to forty-three at starting and from twenty to twenty-eight at stopping. That of operation is thirty-nine-sixty-nine and twenty-two-thirty-two respectively. Neither link frequency nor operation frequency has relation to the engine power of the tractor. There is close correlation between the frequency of link and that of operation.
(2) Concerning to the body organs, the frequency of link and operation of each sample varies scarcely at sense organs but largely at hands and feet. In general, the variation of frequency is larger at starting than at stopping (Table 3). Concerning to control devices, the variation of frequency is remarkable at engine-drive devices, reflecting the wide difference in installatin of devices among samples. The operation frequency is higher at hand contols than at pedals, but the variation of frequency is larger at pedals than at hand controls (Table 4).
(3) Based on the relativity of operation frequency between starting and stopping, sampled tractors can be classified into seven groups as shown in Fig. 3. Investigations on relations between arrangements of controls and operation frequency in each group has drawn the following coclusions about the design of control devices, which may be effective to reduce the frequency of link and operation and to simplify manipulating motions (Table 5).
i) The hand controls should be arranged as bias as possible within the reach of the operator's right hand. The symmetrical arrangement rather increases operation frequency.
ii) The kinds of engine-drive devices should be reduced to minimum, unles inconvenient to driving.
iii) It reduces operation frequency to diminish the subsidiary gear shift lever and to move the pto lever from the left side to the right of operators seat. In hand brake system, the holdfast mechanism is preferable to the lever.
iv) If possible, it is desirable to eliminate the accelerator lever and to depend only upon the pedal.