A cutting tool to cut a hollow vessel includes a conical member, a plurality of grooves, and a plurality of cutting members. The plurality of grooves are disposed in a semi-helix around an outer conical surface of the conical member. Each of the plurality of cutting members is disposed in fixed position within one of the plurality of grooves at a non-zero angle relative to a vertical axis.

According to an aspect of the present disclosure, a low profile travelling pipe cutter is provided which is adapted to perform at least one of cutting and beveling a hollow vessel while traveling around the vessel using a cutting tool mounted thereon. The pipe cutter includes inner and outer carriages, a capstan assembly attached to the outer carriage to which a feed cable is attached, and rollers attached to the outer carriage to which a tension cable is attached. The force adjustment assembly changes the vertical position of the outer carriage relative to the inner carriage to compensate for the pipe cutter going inwardly and outwardly as it travels around a hollow vessel in order to maintain constant pressure caused by the lever tension interface. A guard assembly is provided for covering and uncovering the cutting tool during cutting.

To provide a work tool capable of suppress temperature rise in a motor or a switching element. The work tool includes: a motor; a switching element switchable between an ON-state and an OFF-state, the switching element allowing a current to flow through the motor during the ON-state, the switching element prohibiting a current from flowing through the motor during the OFF-state; target rotation number setting means for setting a target rotation number of the motor; rotation number controlling means for controlling the motor such that the rotation number thereof is brought in coincidence with the target rotation number by changing an ON-duration, during which the switching element is in the ON-state, in one switching period of the switching element; and temperature detecting means for detecting at least one of a temperature of the motor and a temperature of the switching element. The rotation number controlling means is capable of setting an upper limit with respect to the ON-duration on the basis of the temperature detected by the temperature detecting means and changes the ON-duration within a range not more than the upper limit.

A reactor vessel cutting device, including a hoist system; a mechanical cutter; and a cutter carriage secured to the hoist system to be suspended by the hoist system. The cutter is secured to a carriage body of the cutter carriage to be carried by the carriage body. The cutter carriage includes a stabilization system secured to the carriage body and operable to hold the cutter carriage against a vessel wall of the reactor vessel. The cutter carriage is operable to apply the cutter to the vessel wall in a mechanical cutting operation when the cutter carriage is held against the vessel wall by the stabilization system. The hoist system is configured to bear the weight of the cutter and the cutter carriage during the mechanical cutting operation and the stabilization system is configured to carry cutting forces generated during the mechanical cutting operation.