PRINCIPLE AND MAIN PARAMETERS OF A HAND-HELD PINEAPPLE LEAF-TYING MACHINE

Due to the climatic characteristics of northern Vietnam, seasonal boundaries are sometimes unclear. When temperatures shift early from cold to warm conditions, pineapple plants tend to flower and set fruit prematurely, resulting in substandard fruit quality. To address this issue, pineapple growers apply a practice of tying pineapple leaves and crowns to inhibit early flowering, thereby maintaining vegetative growth until the main season, when plants reach the appropriate stage for flower induction. This practice contributes to increased yield, improved fruit quality, and enhanced production scheduling. At present, the tying of pineapple leaves and crowns is performed manually, which is laborintensive and results in low productivity. To improve operational efficiency, the development of a suitable tying device is necessary. This paper presents the research results, calculations, and design of a handheld pineapple leaf-tying device. The device consists of two main components: a crown gripping unit and a wire-tying unit using a stapling mechanism. The crown gripping mechanism simultaneously performs two functions—gripping the crown and pulling it into the tying space. The wire-tying unit is driven by a cam–slider mechanism, which enables the generation of a large pressing force required for staple fastening while maintaining low power consumption.The shoot clamping mechanism performs two functions simultaneously: clamping the shoot and pulling it into the tying space. The strapping mechanism is driven by a sliding cam mechanism, aiming for low power consumption while still generating high clamping force for stapling. The stapling process's drive mechanism was simulated to determine the rotation angle of the stapling arm at approximately 45° and the required driving torque of the arm Mmax = 1.085 Nm. The power of the electric motor driving the arm is Ndc = 5 W.