Shank adaptors are accessories for rock drills

Shank adaptors are a key component in rock drills. They bear the impact and torque of the rock drill, and have a great impact on the rock drilling speed, rock drill and drill bit life. The following is a detailed introduction to Shank adaptors:

I. Definition and classification

Definition: Shank adaptors are the part of the drill bit in the rock drill that bears the impact and torque of the rock drill. It can be a part of the drill bit or made into an independent tail rod.

Classification: Commonly used Shank adaptors include shoulder (flange) type, ear (lug) type and spline type. Among them, the shoulder type Shank adaptors have a hexagonal cross section, with two types of inscribed circle diameters of 22mm and 25mm, and two types of lengths of 108mm and 159mm. They are manufactured by forging technology and are used for light rock drills; the ear type tail is used for inner rotary medium-sized guide rail rock drills, and the drill rod diameter is 25mm and 32mm; the spline type tail is often used for heavy-duty guide rail external rotary rock drills with large torque, and the drill rod diameter is more than 38mm.

2. Material and manufacturing

Material: Shank adaptors use high-quality alloy steel as raw material, such as 35SiMnMoV or 24SiMnNi2CrMo, etc. These steels are specially treated, such as overall carburizing, to improve their hardness and wear resistance.

Manufacturing: The manufacturing process of Shank adaptors is complex, including cutting, forging, annealing or normalizing, hardness testing, machining, carburizing, layer depth testing, quenching, tempering, cleaning, hardness testing, grinding and other steps. Among them, the process route of the heavy-duty rail-type rock drill tail also includes isothermal quenching, low-temperature tempering, cold rolling thread back cutter groove and other steps. These process steps ensure the high precision and stability of the tail.

3. Application and requirements

Application: Shank adaptors are mainly used in mining operations, such as blast furnace rock drills will use Shank adaptors in the process of opening the iron mouth. In addition, it is also widely used in mining engineering, tunnel engineering and other fields.

Requirements: Shank adaptors should be of appropriate length, flat and smooth end surface, perpendicular to the axis, and fit with the drill sleeve of the rock drill (the gap is not greater than 0.5mm). At the same time, the hardness of Shank adaptors should be appropriate, generally slightly lower than the piston hardness, and the quenching hardness HRC should be between 38 and 45. In addition, in order to ensure the service life and performance stability of the drill tail, it is also necessary to use special CNC machine tool processing equipment and processing technology for processing.

Fourth, common problems and preventive measures

Common problems: Shank adaptors may have abnormal breakage and other faults during use. These faults are usually caused by the impact generated during the operation of the rock drill, excessive wear of the drill tail guide sleeve, insufficient lubrication of the rock drill, mismatch between the thrust pressure and the impact pressure, and incorrect installation.

Preventive measures: For the above problems, the following preventive measures can be taken: regularly check and replace the drill tail guide sleeve that is worn beyond the standard; ensure that the rock drill is fully lubricated; adjust the thrust pressure according to the rock condition to avoid empty hitting; and ensure that the rock drill is properly installed so that the center line of the drill tail is coaxial with the center of the front and middle drill support holes.