# Development of Automatic Accumulating Equipment for Roller-Type Onion Pot-Seeding Machine
## 2 Materials and Methods
### Details of Developed Accumulating Equipment  
The main components of the accumulating equipment are the conveyor belt, elevator plate, limit switch, pneumatic-type actuator, stopper bracket, alarm bell, control box, and connecting bracket. Their characteristics and functions are as follows:  
A. Conveyor belt: This transports the pot trays, which pass through hopper 3 of the existing pot-seeding machine, and complete the seeding work, to the accumulating plate (Figure 2). The conveyor belt operates using a motor installed in the lower portion of the supporting frame as a power source. It can adjust the transport speed from 0.03 to 0.3 m/s using the speed controller. The speed controller has 10 stages, and the speed of the first stage is 0.03 m/s. The speed increment for one stage is 0.03 m/s. To transfer the pot trays to the elevator plate, two pairs of conveyor belts are installed with a spacing of approximately 285 mm. B. Elevator plate: This lifts and accumulates the pot trays transported by the conveyor belt. It moves up and down by a pneumatic-type actuator with air compressor. The area of the elevator plate was designed to be almost identical to the area of a pot tray so that it could support in a stable manner any pot trays that are easily bent owing to high flexibility (Figures 3 and 4). Figure 2: Shape of conveyor belt: (**a**) picture and (**b**) 3D model. C. Limit switch: When pressed owing to a contact situation, the limit switch stops the conveyor belt by sending a stop signal to the motor. The limit switch operates the pneumatic-type actuator at the same time by sending a start signal to the air compressor. Located on the supporting frame behind the elevator plate, the limit switch is pressed by the end of a pot (Figure 5). D. Pneumatic-type actuator: Located at the bottom of the elevator plate, the pneumatic-type actuator performs a stroke movement using the air compressor as a power source. Upon receiving a start signal from the limit switch, the pneumatic-type actuator performs a one-time ascent and descent of the elevator plate with the pot tray through the stroke movement. The stroke time can be adjusted by  
Figure 4: Shape of pot tray: (**a**) picture and (**b**) 3D model. Figure 5: View of limit switch: (**a**) noncontact situation and (**b**) contact situation of limit switch with pot tray. Figure 3: Shape of elevator plate: (**a**) picture and (**b**) 3D model. changing the air supply rate of the air compressor through the timer. The stroke time can be adjusted between 0.1 and 3 s. The shape and specifications of the pneumatic-type actuator are shown in Figure 6 and Table 2, respectively. E. Stopper bracket: As a key element in accumulating pot trays, the stopper bracket consists of a bracket, guide, and spring. The bracket enables only an upward tilt by up to 90\({}^{\circ}\), thus it does not block the motion when the elevator plate with a pot tray is raised. After passing of the elevator plate, the bracket returns to the original position by spring force. The side part of the pot tray is placed on the bracket when the elevator plate descends. The side length of the elevator plate is designed to be slightly shorter than that of a pot tray, and thus it does not touch the bracket when it ascends and descends (Figure 7). Therefore, during the one-time ascent-descent motion, the elevator plate returns to the original position, and only the pot tray is supported by the bracket (Figure 8). When the first pot tray is fixed by the stopper bracket, the elevator plate with the second pot tray rises and pushes the first and second pot trays at the same time. When the elevator plate descends, the two pot trays are supported by the stopper bracket. The third and fourth pot trays are accumulated onto the stopper bracket in a similar sequence. In this instance, the first pot tray is located at the top. A total of six stopper brackets are located on both sides of the elevator plate so that the pot trays can be supported at six points. Through this, bending of the pot trays can be minimized.