斜切针接式穴盘蔬菜嫁接机关键机构的设计与试验

Design and test of key mechanism of beveling pin-grafting machine

为提高茄科植物嫁接育苗效率,根据"针接式嫁接法"的嫁接作业要求,设计可直接在穴盘内对幼苗进行嫁接操作的针接式自动嫁接机.设计穴盘定位机构,完成在嫁接作业位置对穴盘的控制;针对砧木的柔嫩性,设计砧木扶直装置和带有导向槽的砧木夹持装置协同完成对砧木形态的控制,实现对穴盘内单行6株苗同时夹持定位;针对接穗处理,设计旋转切削机构对接穗进行切削,提高切削速度,增加切削平滑度;同时,对样机的作业性能进行试验.结果表明,砧木夹持成功率为97.4%,接穗切削成功率为94.4%.嫁接机工作性能稳定可靠,可以适应茄科作物工厂化育苗需求.

Mechanized grafting can reduce labor intensity, improve production efficiency and ensure product quality. The majority of researchers choose traditional grafting methods for their grafting machines, such as cut-in grafting, joining grafting or split grafting. However, the conventional methods either require multiple steps, quality seedlings, or need external clamping to fix the grafted seedlings, which restrict the grafting speed. In this study, an autografting machine aiming at the Solanaceae was designed based on pin-grafting method, which could connect the rootstock and scion with a pin. This method can overcome the limitations mentioned above, because of acting on the aperture disk seedlings directly. The grafting machine was composed of two processing mechanisms： rootstock morphology controlling and scion cutting. The former included three parts： mechanism of location in aperture disk, mechanism of straightening rootstocks and mechanism of clamping rootstocks. The first one, which was designed to control the position of aperture disk during the grafting, was a micro-positioner that could jog the aperture forward to the next line of seedlings after completing the grafting task of the current line. The second and third parts worked together to ensure the rootstock in the right posture and clamped six seedlings in each row of the disk during a period, in which the second one was used to correct the rootstocks in vertical direction with two mechanical arms, while the third one played a similar role in transversal direction. These parts were effective, especially when dealing with the untidy growth of tender seedlings. The latter, i.e. , the mechanism of rotary cutting was driven by a rotating cylinder. This mechanism had six tool holders of which the blades were installed on the top. It made the incision of scion smooth and flush at a high speed with a determined cutting radius. The results of the performance test indicated that the proposed grafting machine was able to accomplish the clamping task with 97.4% success rate and the cutting task with 94.4% success rate. The prototype machine can work steadily and reliably, which suggests its potential for practical application.