Fundamental studies on the leaf-picking machine for mulberry (2) Pulling force of a shoot detachement

• Published in: The Journal of Sericultural Science of Japan Vol. 37; no. 1; pp. 6 - 12
• Main Authors: TAWARA, Toraji, AI, Fusakazu, SUDO, Makoto
• Format: Journal Article
• Language: English
• Published: The Japanese Society of Sericultural Science 1968
• ISSN: 0037-2455; 1884-796X
• DOI: 10.11416/kontyushigen1930.37.6

In order to develop the leaf-picking machine used for the spring mulberry tree, we measured experimentally the pulling-force which remove a shoot from the stem. The measuring apparatus used here was similar to that of the previous report. The results were as follows: 1) On account of a small shoot elasticity and the attaching angle to the stem, the resistance of angular displacement occured when the shoot was transfered from the initial angle to the detachable angle, and consequently the load-elongation diagram of shoot was different in form from that of the leaf. 2) The average pulling-force value required for a shoot detachement at the right angle direction to the stem was about 4.53kg with 12.6kg maximum, and 0.4kg minimum value. The pulling-force values were found to be different according to the shoot weight. These values showed a tendency to increase between 1g and 12g of a shoot weight, but when the weight was over 12g, these values began to decrease possibly due to the existence of a bending moment exerted on the shoot base. The pulling-force value was also different according to the pulling direction. The largest value was obtained from upward pull where detachement was almost impossible to perform; next followed by the value obtained from the right angle pull and the smallest one obtained from the downward pull, which was about 1/3 of the right angle pulling-force value. 3) The amount of work necessary for detachement of the shoot varied according to the direction of force applied. The average work value was 5.55kg·cm for the right angle pull and 6.28kg·cm for the downward pull. 4) All the properties mentioned here and in our previous report support our idea that the pulling method is more suitable as the picking method of the picking-machine than that of the vibration method. It was found, through laboratory computation, that the capacity of the machine for shoot detachement must be twice of that of the leaf, while the pulling direction at right angle was found better than from downward direction. 5) Detachement of the individual leaf by the machine will be possible as we found that there was a large difference between the pulling-force value of the shoot and the leaf.