| 摘要 |
The invention relates to a pick holder (8) having a head (9) with a shoulder (10) thereon and a cylindrical body extending from the shoulder and terminating in a shank (12) whereby the holder is fixed to a cutter head. The holder being provided with a first axial bore (14) extending from said head (9) and of a length in excess of the length of a shank of a pick (1) to be accommodated therein, a second axial bore (16) extends from said first axial bore (14) to the bottom of the pick holder, the junction of said first and second axial bores providing a seat (17) in said pick holder (8). An elastomeric plug (18) positioned in said first axial bore (14) between said seat (17) and the shank of a pick (1) inserted therein, said plug (18) being provided with an axial bore communicating with said second axial bore (16) and rotational means (20) positioned on or in said plug (18) which in use of said pick causes intermittent rotation of said plug in said first axial bore. |
