The computational time analysis of g enetic algorithms

A device constituting a cutting jib or arm for mounting on a rotatable platform of a tunnel driving machine. The device has a main elongate body one end of which is attachable to the platform. A hewing cylinder is disposed for rotation at the other end of the main body. A carriage in the form of a hollow box like structure is mounted on the main body for sliding back and forth and piston and cylinder units are used to effect this movement. A draw pick is supported by side members able to pass over the lids of the hewing cylinder. These side members are pivotably carried by journals connected to the carriage so that the side members move with the carriage along the main body. Further piston and cylinder units serve to move the side members in an oscillatory manner on the journals and about the hewing cylinder to cause the draw pick to effect cutting when the carriage is advanced up to the other end of the main body.