Safe Operation and Precautions for Straw Returning Machines in Nurseries, Farmland and Dry Land
In China's rural nurseries, farmland and dry land, after the autumn harvest there will be large amounts of crop straw. Using machinery to crush the straw and return it to the soil as fertilizer is a very good fertilization measure. So what are the safe operation knowledge and precautions for straw returning machines?
I. Working principle of the straw chopping and returning machine
According to differences in overall structure, straw chopping and returning machines are divided into two types: one is the horizontal straw chopping and returning machine, and the other is the vertical straw chopping and returning machine.
a. Horizontal straw chopping and returning machine
The knife shaft of the horizontal straw chopping and returning machine is arranged horizontally and laterally, and the flails mounted on the knife shaft rotate within a longitudinal vertical plane. The horizontal straw chopping and returning machine is mainly composed of a transmission mechanism, a chopping chamber and auxiliary parts. The transmission mechanism consists of a universal joint drive shaft, a gearbox and a belt transmission device. The chopping chamber consists of a housing, blades and blades hinged on the knife shaft. Blade forms include L-type, straight-blade type, hammer-claw type, etc. Auxiliary parts include the suspension frame and depth-limiting wheels, etc. By adjusting the height of the depth-limiting wheels, the stubble height can be adjusted, while also ensuring that the flails do not strike into the soil.
The horizontal straw chopping and returning machine is connected to the tractor power take-off shaft. The power output by the tractor power take-off shaft drives the driving pulley to rotate through the universal joint and the second shaft of the main gearbox. The driving pulley drives the driven pulley and the chopping drum to rotate through the V-belt. The hammer claws mounted on the chopping drum rotate with the drum and open under the action of centrifugal force. The high-speed rotating hammer claws pick up the crop straw on the ground and feed it into the chopping chamber formed by the casing and the drum. At this time, the straw is cut by the first row of fixed teeth, and most of it is chopped. The straw that is not chopped is affected by the change in the cross-section of the folded-line inner wall of the casing, causing the airflow speed to change, so that the straw is repeatedly struck by the hammer claws and chopped. When the straw enters the gap between the hammer claws and the rear row of fixed teeth, it is sheared and torn again, and the chopped straw is evenly spread in the field through the guide plate. The depth-limiting roller that follows immediately presses the remaining stubble together with the straw onto the ground, thus completing the entire working process.
b. Vertical straw chopping and returning machine
The vertical straw chopping and returning machine is composed of a suspension frame, gearbox, housing, chopping working parts, depth-limiting wheels and front guard, etc. The vertical straw chopping and returning machine is connected to the tractor power take-off shaft. The power output by the tractor power take-off shaft enters the horizontal shaft through the universal joint drive shaft and the transmission gearbox, and after speed increase and direction change by the bevel gear, the vertical upright shaft rotates, driving the cutterhead mounted on the upright shaft to work. Fixed knife blocks are installed on the side plates of the housing, and a feeding guide device is set at the front feed inlet, so that the stalks on both sides gather toward the middle, increasing the number of cuts by the flails on the straw and improving the chopping effect. A front guard with guard chains or guard plates is also installed at the front of the housing, so that only straw is allowed to enter from the front, and chopped straw is not allowed to be thrown out from the front. A discharge guide plate is installed at the rear discharge outlet of the housing to improve the uniformity of straw spreading. The depth-limiting wheels are installed on both sides or at the rear of the machine. By adjusting the depth-limiting height, the stubble height can be adjusted, ensuring that the flails do not enter the soil and that there is good chopping quality.
II. Adjustment of the straw chopping and returning machine
a. Installation and adjustment of the universal joint
The assembly position of the universal joint should be such that the end with the square shaft is installed into the input shaft of the chopper, and the end with the square tube is installed into the tractor output shaft. The inner and outer sections should cross, and the two inner yokes and the two outer yokes should respectively maintain the same horizontal installation direction. Incorrect installation can easily cause excessive vibration and damage to machine parts. During operation, the horizontal angle between the drive shaft and the ground must not exceed 10°.
b. Adjustment of the connection to the tractor
After the straw chopping and returning machine is connected to the tractor, the machine unit should be debugged. Place the machine unit on a horizontal surface for observation, check whether the returning machine is connected properly, and adjust the length of the left and right suspension rods so that the machine is horizontally level. At the same time, adjust the lower connecting shaft into the long hole so that it can float during operation. Adjust the length of the central pull rod so that the machine is longitudinally level. For the height gap between the knife teeth and the ground, adjust the land wheels in the field so that the distance between the tooth ends and the ground is 1-2 cm.
III. Operating knowledge for the straw chopping and returning machine
a. Before operation, first go to the field to be worked and take a look, understand the crop maturity and soil hardness, remove obstacles for the machine to enter the field, level the headland furrows (to avoid damage to the universal joint), remove large stones in the field, and set markers, etc.
b. Before operation, check the technical condition of the towing tractor to ensure it is in good condition, check all parts of the returning machine, tighten loose parts, and add gear oil to the gearbox. Generally, the most suitable oil level height is with the large gear immersed to one third of the oil surface. Lubrication points should also be filled with grease. After inspection, the machine should be run empty for 5-10 min. Only after confirming that all components are operating well can operation begin.
c. During operation, first raise the returning machine to a height of 20-25 cm between the hammer claws and the ground. The lifting position must not be too high, so as to avoid damage caused by an excessively large deflection angle of the universal joint. Engage the power take-off shaft, rotate for 1-2 min, engage the working gear, and slowly release the clutch pedal. At the same time, operate the hydraulic lift adjustment handle so that the returning machine gradually lowers to the required stubble height, then increase throttle and begin normal operation.
d. During operation, promptly clean off tangled grass. When removing tangled grass or troubleshooting, the machine must be stopped first to avoid personal injury. Check the tightness of the V-belt at any time to avoid reducing the knife shaft speed, affecting chopping quality and aggravating V-belt wear.
e. It is strictly prohibited to start the straw chopping and returning machine under load. When the machine is running, sudden raising and rapid lowering are strictly prohibited. Before the machine unit turns, the machine should first be raised. It is strictly prohibited to turn while the machine is in the working position, so as to avoid damaging the limit chain. It is strictly prohibited to remove the drive belt guard.
f. During operation, flails are prohibited from working in the soil, to prevent unlimited increase in torque and causing machine damage, and avoid soil ridges, tree stumps and other obstacles. If it is found that the hammer claws are striking soil, the height of the land wheels from the ground or the length of the tractor suspension pull rods should be adjusted.
g. If there is an abnormal noise during operation, stop immediately and check. Continue operation only after the fault is eliminated. It is strictly prohibited to inspect the machine while it is running.
Appendix: What causes the corn straw returning machine to shake when the blades are not installed? How to solve it?
a. The dynamic balance of the knife shaft has failed. It is recommended to replace the knife shaft.
b. The two pulleys are not coplanar, or the groove surfaces of the two pulleys are tilted. It is recommended to have it adjusted by after-sales service.