| 摘要 |
[PROBLEMS] To fill an air cylinder with air without installing an air compressor in an air buffer device. [MEANS FOR SOLVING PROBLEMS] The buffer device (2) consisting of a piston (21) and the air cylinder (22) is incorporated in an excitation device (1), and it constitutes a drill head with a speed reducer (4). When the drill head is raised, the air cylinder (22) rises with respect to the piston (21), and atmosphere is sucked to an air damper room (23) through a check valve (25). When the drill head is lowered and a drill bit is brought into contact with a drill face, the piston (21) cannot descend and the air cylinder (22) relatively descends with respect to the piston. Since the check valve (25) does not let air in the air cylinder (22) escape to an atmosphere-side, air in the air damper room (23) is compressed, and drop of the drill head stops when pressure in the air damper room (23) and weight of the drill head are balanced. Thus, the buffer device having an appropriate spring coefficient can be obtained. |
