HOLE CUTTING APPARATUS

摘要

An apparatus for cutting a hole through a curved wall of a structure (1) such as a pipe. A cutting tool drive assembly supports a cutting tool (21) so that the cutting tool (21) is rotatable about a predetermined cutting axis (22) which is fixed relative to the drive assembly. The drive assembly is mounted to rotate about a support (8) which in use is fixed in position relative to the tube (1) to be cut. The drive assembly is rotatable about an axis (12) defined by the support, that axis (12) being perpendicular to the tube (1) at a position which is central to the position in which the hole is to be cut. The drive assembly is mounted on a support linkage (13-19) which enables it to move relative to the support (8) so as to vary the inclination of the cutting axis (22) relative to the support axis (12). The drive assembly or linkage (13-19) defines a head which bears against the tube surface and determines the position of the drive assembly relative to the tube (1). The geometry of the linkage (13-19) is such that as the drive assembly is moved about the support axis (12) the head follows the curved surface of the tube (1) and the cutting axis (22) is maintained substantially perpendicular to that surface.