Cutter bit assemblies and arrangements for use with mining or tunnelling machines

A cutter arrangement for a plough, said arrangement comprising a tool carrier, holders with sockets supported by the carrier, cutter bits with shanks fitted in the sockets of the holder, means for securing the shanks of the cutter bits in the sockets, said securing means comprising securing elements displaceable within the holders to engage the shanks of the cutter bits and hydraulic means for actuating the securing elements wherein the hydraulic means comprises chambers in the holders containing pistons displaceable with pressure fluid to act on the securing elements and a common hydraulic pressure medium supply for all the chambers.

In a cutter assembly for a mineral winning machine or a tunnel driving machine, said assembly comprising a cutter with a shank and a holder with a socket for receiving the shank of the cutter and means for securing the shank on the socket;

• said securing means comprises a securing element actuable to selectively engage with the shank of the cutter bit and hydraulic means for actuating the securing element, wherein the hydraulic means comprises a first chamber in the holder, a servo piston which can be subjected to pressure medium in this first chamber and a second chamber from which pressure medium can be caused to flow to the first chamber to displace the servo piston, the servo piston and the securing element are parts of a one-piece component and axial and radial borings in the one-piece component connect the first chamber to another bore leading to the second chamber.

In a cutter assembly for a mineral winning machine or a tunnel driving machine, said assembly comprising a cutter with a shank and a holder with a socket for receiving the shank of the cutter and means for securing the shank on the socket;

• said securing means comprises a securing element actuable to selectively engage with the shank of the cutter bit and hydraulic means for actuating the securing element, wherein the socket of the holder has a rear wall portion with an abutment surface engageable with an abutment surface of the cutter and the securing element acts to secure the cutter by urging those abutment surfaces together.