1 fruit checkweigher working principle and overall structure

The main part of the mechanical system of the fruit checkweigher includes the production line bracket, transmission system, fruit tray and grading box. Mechanical system is the overall movement of the production line in the process of power supply parts, mainly for the fruit tray transmission work to provide power; other components in the installation is the main component of the support force, but also weighing and unloading parts of the installation of the core foundation; production line bracket is the fruit sorting scale in all parts of the installation of the foundation; transmission system in the installation of the main components are more including electric motors, gear reducer, and power and power output chain wheel, etc.; fruit checkweighing machine mechanical system includes the main parts of the production line, the fruit tray and grading box. Power output sprocket, etc.; fruit tray structure and conveyor chain two parts directly riveted, the conveyor chain movement will drive the fruit tray movement, the conveyor chain is in a vertical state, and the ground to maintain a vertical state; conveyor chain below the support structure to wear-resistant plate based on the level of the conveyor chain in the operation of the chain has played a good role in stabilizing the weighing module to ensure the accuracy of the operation.

The main components of the weighing module are weighing platform, weighing top plate, weighing bottom plate and load cell, etc. The weighing module should be fixed directly on top of the production line bracket in the installation; the fruit pallet is directly connected with the double-pitch conveyor belt, and the fruit pallet is transported to the weighing area where it will be contacted with the weighing platform, which is subjected to the force, and the pallet is completed according to the rotary axis to weigh the fruits and unloading the fruits, and the shape of the pallet is concave, which can gradually feed the fruits through the feeding device, which can gradually feed the fruits. After the feeding device can be fruit gradually into the fruit tray, realize the transmission of fruit arrangement; tray and fruit contact part of the plastic products, can prevent the surface tray to the maximum extent of fruit mechanical damage; fruit grading and unloading parts with the completion of the sorting of fruits according to the device system signals flip tray, and ultimately complete the fruit grading and unloading work. Image acquisition system includes cameras, lenses, light sources and light boxes, mainly in the fruit sorting scale transmission, the fruit on the conveyor belt for dynamic image collection, and at the same time will be transmitted to the image processing system. Weight class on the fruit discernment system is divided into two parts of the weighing platform and weighing sensors, real-time processing of fruit transmission in the weighing sensors received by the information data, the fruit obtained from the comprehensive information to be considered in a comprehensive manner, so that the weighing control system of each fruit class rating.

2 fruit sorting scale overall design

2.1 Fruit sorting scale production line bracket design

Fruit sorting scales in the design of mechanical systems should first determine the location of the parts installed to ensure that the overall process of fruit transmission direction is clear, fruit sorting scales in the installation of the production line process, the device includes loading device, detachment device, reflux part, weighing module, unloading components and fruit grading box and other parts of the production line in the length design should be combined with the actual demand for its appropriate adjustment; on the conveyor chain selection should be based on the number of sections, the number of sections, the number of sections of the chain should be selected by the number of sections. Chain selection should be based on the number of sections, in different lengths of the design of the production line between the bracket settings should be kept appropriate.

2.1.1 Production line support design

The actual purpose of installing the production line support in the fruit sorting scale is to provide support for the installation of other parts. In the overall size planning of the production line, its length should be controlled to maintain a reasonable ratio with the approximate size of the fruit. In order to successfully achieve the design goals in the later application, it is necessary to leave a certain margin for the design of the production line length. The production line bracket can be divided into two segments for design and installation, once the actual design and installation of the production line length requirements become more appropriate to increase the number of bracket segments. After the production line is installed to the designated position, the production line should be fully connected to the production line bracket with the help of bolts, constituting an integrated production line; the production line should be properly adjusted through welding in the connection of the bracket support part, and the overall horizontal height of the production line should be regulated.

2.1.2 Encoder fixing design

In the fruit detection scale in the fruit movement position determination process, should be based on the rotary encoder as a system. Rotary encoder use, its actual working principle is in the fruit sorting scale in the production line of the transmission chain of the internal rotary encoder pulse signal for data determination, symmetrical weighing system transportation and grading unloading device time base for control. In the sorting scale transmission of fruit in the process, there is a certain interval between the production line, at the same time in the production line rubbing mixing, the chain speed and the speed of the transmission axis corresponds to the speed between the fruit weighing in the control of the module frequency, the rotary encoder pulse signal frequency control as well as timing adjustments should have a certain safeguard to ensure that the machine running synchronization. Therefore, the number of rotary encoder signal timing in operation, calculate the fruit in the transmission line position and distance, it can be seen, in the weighing of fruit module design, rotary encoding is an indispensable part of the sorting scale production line.

2.2 Transmission system design

Mechanical transmission system is composed of mechanical structure as the core, according to the actual needs of the combination, the final formation of the transmission system, the main function of the application of fruit sorting scale is to change and adjust the rate of the transmission device, to ensure that the machine can achieve the predetermined goals in operation. At the same time, in the prime mover in the power output and torque actual transmission, according to the actuator, to ensure that the expected movement in the power effect can be completed according to the transmission requirements.

Transmission system in the actual design and installation, generally divided into three levels of transmission: first, the motor in the installation, the spindle and reduction components between the input shaft transmission; second, the transmission of the reducer is located in the middle of the input and output shafts; third, the reducer in the power of the output and the work axis. In the design of sorting scale apparatus and weighing module, the first level of transmission should be directly connected to the motor and reduction equipment; the second level of connection equipment is gear reducer and gear transmission; the third level in the power output should be transmitted with the transmission connection wheel.

2.3 Weighing platform design

In order to ensure the application of the weighing platform, the design and installation of sorting scales should be removable, to better realize the good use of the weighing platform, to avoid the occurrence of rust, thus affecting the weighing accuracy. In the weighing platform installation, it should be connected with the load cell with countersunk head screws, when the assembly is complete, the use of sealant will be equipped between the countersunk holes coated with flat, to ensure the smoothness of the fruit pallet in the transportation; in the fruit pallet transportation, the weighing platform and the conveyor belt contact will not be subjected to a large impact, which will not have an impact on the actual accuracy of the measurement data. Therefore, in the design of the weighing platform, it should be based on the specifications of the fruit sorting system.

3 Conclusion

In the current application of fruit sorting scale machinery and equipment, for weighing, the domestic research is less, through the better design of its mechanical system, combined with the weighing module, can improve the quality of fruit selection effect, and gradually reduce the system application error. In the future application of mechanical systems, the relevant technical personnel need to take a more reasonable way of data processing, to achieve accurate weighing of fruit.