The main reasons for the inability of the chuck to firmly grip the drill pipe are mechanical failures of the gripper, as follows:

1. The gripper cannot be fully opened or the opening amount is insufficient. The gripper is a combination of four screws that connect the main oil cylinder, left slip seat, right slip seat, and auxiliary oil cylinder into one. If the four screws are subjected to uneven force, the movement of the gripper is hindered, and the opening amount is uneven, resulting in the inability of the gripper to open normally. In addition, the tightening transition of the nuts on the four screws also causes the gripper to not open properly. A reasonable adjustment of distance is to leave a disc spring outside the spacing ring.

2. The gripper cannot firmly grip the drill pipe, resulting in slipping. First, check the wear condition of the slip, and then check if the disc spring is damaged. If there is excessive wear of the slip or damage to the disc spring, it should be replaced.

3. During the drilling process, the gripper fails to grip the drill pipe. In this case, it is often because the drilling slag plug is blocked in the groove of the left and right movable slip seats of the gripper, causing inconvenience in the movement of the slip seats and resulting in the inability to clamp the drill pipe. Therefore, during the drilling process, it is necessary to regularly clean the gaps of the gripper, or install a rubber baffle in front of the gripper to prevent a large amount of drilling debris from entering the active gaps of the gripper, reducing the amount of drilling debris stuck in the gripper. Nevertheless, it is necessary to regularly clean the gripper to maintain normal operation.

4. Due to the influence of improper opening hole position or unstable displacement of the drilling rig, the gripper is not aligned with the hole position, resulting in uneven friction of the drill pipe and excessive resistance of the gripper to grip the drill pipe, which affects the clamping force. When the above problems occur during drilling work, the position of the machine body should be adjusted in a timely manner to avoid deviation and grinding of the drill rod.

5. The gap between the sliding plate of the gripper and the slot is small. When the drilling slag enters the slot gap, the gripper is stuck and cannot move or center freely. Therefore, regularly clean the gripper tray and slot to ensure smooth movement of the gripper.