[Research and development of power ladder and fruit wrapping machine]

Three-wheel power ladder for harvesting fruits was designed and constructed with 196 cm wide and 530 cm long. The platform and the wheel were directly driven by hydro-static drive system and the platform could be lifted up to 420 cm of high. The three-wheel power ladder moved forward at the speed of 5 km/hr and could be turned by fixing one of the two front wheels. Performance of the power ladder was tested amongst 5 methods of mange harvesting, ie. 4 m long rattan mango picking rod 3-wheel power ladder, 3-wheel power ladder with 2 m long rattan picker, 4-wheel power ladder, and 4-wheel power ladder with 2 m long rattan picker. Harvesting method and mango tree height significantly affected the harvesting capacity (at 5 percent significance level). Mango fruits at high level could be picked up more slowly than those at low level. Mechanized harvesting could be achieved more quickly than manual harvesting (with long rattan picking rod) at the 5 percent level of significance. Mango harvesting by the 3-wheel powerladder with 2 m long rattan picking rod showed the highest capacity of 140.6 kg/hr while manual harvesting with the rattan picking rod exhibited the lowest capacity of 76.0 kg/hr. Two types of fruit wrapping machine (FWM) - one wrapping (OW) and multiple wrapping (MW) - were designed, constructed and tested. FWM mainly consisted of head and body. The head was made of transparent 10 mm thick plastic circular disk of 240 mm diameter. The disk was featured with 100 mm circular hole at its center, pulling arm and finger to wrap up the mouth of plastic bag around a fruit. The body was made of 1/2 inch steel tube, 1 m long (MW type) or 74 cm long (OW type). It held a no.25 chain carrying 100 mm O-ring/s to wrap fruit/s. Evaluation of FWM& indicated that for a seperate fruit or a bundle of fruits having total diameter of 73 mm or less the OW-type could wrap up 51.7 seconds/bag with bag opening after wrapping = 2.4 mm. With the MW-type the wrapping capacity was averagely 61.6 seconds/bag with bag opening after wrapping = 7.3 mm. The MW machine could continuonsly wrap 3 bags per cycle and continuously repeat wrapping for the next cycle.