Operating a Rotary Drill Rig with Mechanical Locking Rod
1. Lower the drill rod to the working face.piling equipment for sale
2. After the drill bit is at the bottom of the hole, operate the power head to slowly rotate the drill rod clockwise. Simultaneously, operate the power head's pressure cylinder to apply downward pressure to find the pressure lock. The load on the power head will increase significantly (a sudden increase in power head motor pressure and a significant decrease in power head speed will occur). At this point, stop applying pressure. Continue rotating the power head clockwise for 1-2 revolutions, ensuring that the lower end face of the key plate inside the drive sleeve is completely in contact with the outer pressure surface of the drill rod (fully locked). Continue applying pressure and drilling until the drill bit is full.
Fully locked diagram
3. Lift the drill string.
(1) Lift the power head so that the upper surface of the power head contacts the drill pipe damping pad and releases the pressure from the pressurizing cylinder.
Schematic diagram of lifting power head
(2) Lift the power head again H=N*50 (N=1 when the second section of drill rod is fully extended from the first section; N=2 when the third section is fully extended from the second section, and so on), so that the upper end of the inner key of the upper section contacts the moving ring of the lower section (lifting the lower section to avoid the phenomenon of hitting the rod after the suspension and reverse unlocking). If the innermost section of drill rod is not fully extended, the lifting amount H can be appropriately increased by 100-200mm, because in this way the drill bit will not leave the bottom of the hole and will not affect the reverse closing of the bucket gate; if the innermost section has been fully extended, the lifting amount H is calculated according to the formula. If the value of H is increased, the drill bit will leave the bottom of the hole, the reverse resistance will decrease, and unlocking and closing the bucket gate will be difficult.piling equipment for sale
Continue lifting the power head (see diagram)
(3) Then reverse the power head 2-3 times to ensure that each section of the drill rod is fully unlocked and the drill bit bucket door is closed. Continue to reverse the power head, start the main winch to lift the drill rod, keeping the power head position unchanged so that the locking point can be quickly found and locked in the next working cycle. During the lifting of the drill rod, the power head should be slowly reversed continuously to prevent accidental locking during the lifting process, which could cause the rod to be pulled or smashed.
4. Remove the soil.
5. After one working cycle, repeat the cycle until the hole is formed. (After several working cycles, when the stroke of the pressure cylinder is close to the end, the pressure cylinder should be pulled up about one pressure stroke to quickly find the next pressure locking point of the drill rod and continue drilling downwards).
Schematic diagram of pressurization stroke
Precautions: During the lifting of the main winch, the power head should be continuously and slowly reversed to prevent the drill rod from suddenly locking when the drill bit scrapes against the hole wall. If the operator finds that the drill rod is not fully unlocked during the lifting process, based on the main winch pressure gauge or personal experience, the drill rod should be lowered back into the hole, and the power head reversed to unlock it again. Unlocking by shaking the drill rod in forward and reverse directions in mid-air is strictly prohibited, as this operation will cause severe damage to the drill rod! piling equipment for sale
