Improved design and experiment of profiling and recycling plastic film mechanism for clamping finger-chain type device of recycling residual plastic film

Abstract: The existing clamping finger-chain type device of recycling plastic film has the problem of poor profiling quality of film collecting operation and instable work performance, so the profiling and recycling plastic film mechanism with single hinge has been designed. The designed device is mainly composed of 2 parts which are profiling mechanism and film collecting mechanism. Whole film collecting device consists of multiple mechanisms of profiling and recycling plastic film mechanism with single hinge. And profiling can be separately performed when each profiling and recycling plastic film mechanism with single hinge is operating. The profiling mechanism is mainly composed of the profiling frame, the film cutting disc, the profiling wheel, compression mechanism and scraping plate, and so on. The role of the scraping plate is to scrape the soil on the profiling wheel, in order to avoid too much clay on the profiling wheel and the increase in size, which result in insufficient finger insertion depth. The mechanism for collecting residual plastic film is mainly composed of film collecting frame, upper film-collecting sprocket, lower film-collecting sprocket, film collecting chain, clamping finger, supporting wheel and tension mechanism. The front part of the profiling frame is hinged on the frame, and the rear part is hinged on the lower film-collecting sprocket shaft. In addition, the profiling wheel is arranged at the shaft end of the lower film-collecting sprocket. The film cutting disc is fixedly connected to the side of the profiling wheel. Under the effect of compression mechanism and the gravity, the film cutting disc and the profiling wheel roll close to the ground. Because the lower film-collecting sprocket is coaxial with the profiling wheel, the lower film-collecting sprocket is undulating along with the profiling wheel. At the same time, the film collecting frame can move up and down on the supporting wheel. When the clamping finger chain turns around the lower chain sprocket, it has a stabilized distance between the clamping finger and the ground. Then the surface profiling can be completed when the residual film is clamped by the clamping finger. When the profiling wheel and finger chain roll forward, the mechanism for collecting residual plastic film will not be blocked, because there is suitable reserved space between mechanisms for collecting residual plastic film. After the upper and lower profiling operation of the device are analyzed and discussed, the structure size parameters of profiling mechanism are determined. By analyzing the movement of the device, it is concluded that the jump distance from the highest point to the landing point is negatively correlated with the stiffness coefficient of the compression spring, and is positively related to the operation speed of the machine. The experiment was conducted on a test ground with complex field environment, uneven ground and large surface firmness. When the traction speed of tractor was 5-5.5 km/h, the diameter of film cutting disc was 280 mm and the diameter of profiling wheel was 220 mm, the recovery rate of residual plastic film was 93.1%, and the profiling wheel had obvious up and down movement relative to the frame. After the operation of the device, there were regular scratches under the effect of fingers on the surface ground, which indicated that the reliability of finger entering into the soil has been increased. There were no obvious bounce and impresses when the profiling wheel passed the convex and concave on the ground. The profiling hysteresis and profiling hypersensitivity did not occur in the experiment, which indicated that profiling and recycling plastic film mechanism with single hinge can meet the technical requirements of residual film collecting. The research results can be helpful to solve the problem of pollution of residual plastic film.