Holder for the attachment of cutters to mining and tunnelling machines

DETAILED DESCRIPTION This problem is solved according to the invention substantially in that into the cutter receiving means of the holder an insert surrounding the cutter shank is inserted with axial play, said insert carrying a shut-off member which engages into the coolant supply line of the spray nozzle and which frees the coolant supply to the spray nozzle when there is an application of a pressure load on the cutter and shuts off said supply when there is no application of load on the cutter.
With this construction of the cutter, the wear which is inevitable due to the rough operating conditions when using mining extraction and tunnelling machines underground occurs mainly at the insert surrounding the cutter shank so that to obviate wear damage which is detrimental to the work of the cutter, in most cases only the insert need be replaced.
This also applies to a wear of the shut-off member in the coolant supply line, by which the coolant spraying of the cutter cutting path is in controlled dependence upon the application of a pressure load.
An advantageous embodiment of the cutter is obtained if the shut-off member surrounds the insert sleeve annularly and lies between two axially displaced annular passages which are formed by the insert sleeve and the holder receiving means and one of which communicates with a coolant supply passage coming from the machine and the other of which communicates with a coolant supply passage terminating in the spray nozzle.
In this embodiment, the shut-off member has on the one hand a robust construction while on the other hand the insert sleeve can be turned in the holder body without impairing the control of the coolant flow to the spray nozzle.
To enable inaccuracies in the shut-off region to be easily compensated and to avoid impairing the blocking function of the shut-off member, it is also expedient for the latter to be provided with a conical shut-off surface which cooperates with an annular shoulder, preferably provided with a seal in the holding receiving means