| 摘要 |
Apparatus for retaining a device for breaking a mass of material in a hole in the material on activation comprises a tube (2) which houses retaining members comprising blocks (5) and hardened bits (6) and a wedge (14). The apparatus is connected to the device by a screw-threaded tube (4) which also serves to advance the wedge (14) in the housing once the tube has been fully screwed into the device. The advancing wedge (14) pushes the blocks (5) and bits (6) into contact with the mass of material to return the apparatus and device in that mass. Means may be provided for equalizing the lateral forces on the blocks in the event that the tube (2) is not centrally located in the hole in the mass of material. |
