Abstract: A tube cutter designed for cutting a pipe where access is limited to the interior of the tube only. A rotatable cutter head mounted at the end of an elongated drive shaft carries a plurality of cuffing wheels. The tube cutter is inserted into a tube to be cut from one end thereof using the elongated drive shaft to position the cutter head in the tube. When the cutter head is inserted into the predetermined location, a feed drive is energized which rotates a scroll head to cause the cutting wheels to move in a radial direction to advance and engage the interior surface of the tube in a concentric manner undergoing cutting. When the tube has been severed, the feed drive rotation is reversed to retract the cutting wheels into the rotatable head, so as to enable removal of the rotary tube cutter from the tube.

Abstract: An internally expanding cutting device is used for severing large cylindraceous objects in two. The device comprises a spider mechanism in which a series of radially extending arms are attached to a central hub. The spider is arranged to be mounted on a base member so that the spider mechanism is free to rotate. A series of self propelled cutting wheels are mounted on the arms of the spider to allow the cutter wheels to contact the interior wall of the cylinder to be cut. The cutting wheels are arranged to drive the spider in a rotational manner while the cutter wheels are progressively pushed outwardly to deepen the cut. Each wheel follows in the track of the previous cutter wheel until the cylinder is severed.

Abstract: A blade for cutting cylindrical structures is disclosed. The working face of the blade is adapted for piercing and cutting. The blade of the invention works to cut cylindrical structures without substantially deforming the wall of the structure adjacent to the cut. The blade may be of use in a variety of devices for cutting cylindrical structures.