Study On Pneumatic Type Automatic Tray Feeder And Automatic Tray Stacker

As an important part of mechanization of rice production throughout the whole course, widely used rice factory seedling nursery line includes trays feeding, subsoil spreading, subsoil compaction, precision seeding, topsoil spreading, water spray and tray taking. At present most of the work that feeding the trays into the rice seedling nursery planter and taking the trays away is finished one by one manually. It not only make large labor-intensive and easy to cause the fatigue damage of workers, but also restricts the seedlings production efficiency. Therefore, in order to improve the automation and efficiency, reduce labor intensity of the rice factory seedling nursery line, it's necessary to develop the automatic tray feeding and automatic tray stacking device.At present, the automatic tray feeder and automatic tray stacker have been studied both at home and abroad. Foreign automatic tray feeder and automatic tray stacker have a better performance, but the cost is higher and difficult to bring in. Domestic products are yet to be further improved in terms of the reliability and efficiency. In particular, from the viewpoint of light weight and simple way for rice cultivation, the soft trays that matching the rice seedling nursery lines are mainly used to reduce production costs. The existing automatic tray feeder and automatic tray stacker are not seen applied in the soft trays. Therefore, it is urgently to develop a simple structure, high efficiency and reliable operation of automatic tray feeder and automatic tray stacker, and a kind of automatic tray stacker that suitable for soft trays.(1)Overall scheme designing of pneumatic type automatic tray feeder and automatic tray stacker. Through the characteristics analysis of currently used trays structure,(1)the overall scheme of pneumatic type automatic tray feeder was confirm. Through the proximity switches detecting of the control system, the stacking trays could be lifted or dropped by the tray dropping mechanism, and the trays could be automatically supplied one by one rapidly.(2)The overall scheme of pneumatic type automatic tray stacker was confirm. Based on the programmable logic controller(PLC), the trays were detected by a proximity switch of the control system, and the tray stacking mechanism was controlled to lift and drop the trays to achieved the tray stacking automatically. In addition, the cover plate of the soil anti-falling mechanism was controlled to lift after stacking and finally the device can effectively prevent the soil falling out of the tray in the process of stacking that lead to seeds exposed.(2)Key components designing of pneumatic type automatic tray feeder and automatic tray stacker.(1)The tray conveying mechanism of automatic tray feeder was developed. By the movement analysis of conveying model, the speed parameter relationship of the conveying mechanism between seedling nursery line and automatic tray feeder was confirmed to meet the trays stacking space. The tray dropping mechanism of automatic tray feeder was developed. The structure and kinematic parameters were analyzed and confirmed. The control system of automatic tray feeder was developed. The structure composition and control process of electrical and pneumatic circuit was designed.(1)The soft tray pallet was designed to satisfy the requirement of the commonly used soft tray stacking. The tray conveying mechanism of automatic tray stacker was developed. By the movement analysis of conveying model, the speed parameter relationship of the conveying mechanism between automatic tray stacker and seedling nursery line was confirmed to ensure zero-gap conveying. The tray lifting mechanism and the soil anti-falling mechanism of automatic tray feeder were developed. The structure and kinematic parameters were analyzed and confirmed. The control system of automatic tray stacker based on PLC was developed. The electrical and pneumatic circuit was designed. By using software GX Works2, the PLC was programmed and debugged. It provides the basis for the establishment of the control system.(3) Performance testing of pneumatic type automatic tray feeder and automatic tray stacker.(1)The automatic tray feeding test was carried out which regarded feeding success rate as index and regarded the productivity, the feeding time of tray dropping mechanism and the stacking trays deviation as factors. Test results showed that When the stacking trays deviation was 0~6 mm and the feeding time was 0.8 s, the feeding success rate was 98.67%~100% at a productivity of 600~1000 trays per hour.(2)The automatic tray stacking test was carried out which regarded stacking success rate and seeds exposed rate as indexes and regarded the lifting speed of tray stacking mechanism, cover plate installation conditions and productivity as factors. When the lifting speed was 0.15m/s, the cover plate installing with pneumatic cylinder and the productivity was 600-800 trays per hour, the stacking success rate of hard tray and soft tray was 100% and 99%-100% respectively while the seeds exposed rate was 0.28% and 0.60% respectively. In addition, the used trays was divided into three levels and the test was carried on. The results show that in the actual production process, the mild degree trays has less affected on the indexes with 96% stacking success rate and 1.0% seeds exposed rate. And the stacking success rate and the seeds exposed rate could be ensured by adjusting the relative distance of the lifting finger when suing the moderate degree trays. The severe degree trays should be avoided to use because of the poor result.