| 摘要 |
The submitted design has same functions and usage as conventional drill heads. It consists of two parts, a solid and a recess truncated cone with 4 sets of troughs and teeth. The two parts are locked together with 4 slotted spring pins. The highly worn drill head can be detached and replaced even with one of different size or different type if needed. Such design feature is thus highly versatile and economical. The design ensures even distribution and absorption of impact force and torque. The integrity of the whole structure while drilling is thus maintained. |
