Pipe cutter having non-rotating, overlapping knives
AssigneeLindab AB
InventorWilhelmus P.H. Castricum
Life of this patent
Estimating the term…
Abstract
A pipe cutter having non-rotating, overlapping knives is provided. Also provided is a pipe cutter having non-rotatable overlapping knives wherein one of the knives is continuously reciprocated.
Claims20
An apparatus for cutting spirally formed pipe wherein the pipe is actively rotated in a predetermined direction about a longitudinal axis of the pipe and the pipe moves along the longitudinal axis, the apparatus comprising:
- a non-rotatable, radially fixed inner knife positioned inside the pipe;
- a non-rotatable outer knife positioned outside of the pipe;
- and
- a knife positioner connected to the outer knife, the knife positioner adapted to move the outer knife between a standby position, wherein the outer knife is spaced away from the pipe, and a cutting position, wherein the outer knife maintains a radially fixed position that overlaps the inner knife such that the pipe is severed as it rotates between the non-rotating, overlapping inner and outer knives and moves along the longitudinal axis.
An apparatus for cutting spirally formed pipe wherein the pipe rotates about a longitudinal axis and moves in the longitudinal direction, the apparatus comprising:
- a non-rotatable inner knife positioned inside the pipe;
- a non-rotatable outer knife positioned outside of the pipe, the outer knife having at least two curved cutting edges;
- and
- a reciprocating knife positioner wherein the reciprocating knife positioner comprises a lifting block and a reciprocating block, the lifting block attached to a lifting assembly adapted to move the outer knife between a standby position and a cutting position, wherein the inner and outer knives overlap and puncture the pipe in the cutting position, and wherein the reciprocating block is adapted to continuously reciprocate the outer knife in a radial direction with respect to the longitudinal axis of the pipe while maintaining the inner knife and the outer knife in an overlapping relationship during a cutting operation.
A method of cutting a spirally formed pipe comprising the steps of:
- continuously rotating a spirally formed pipe in a predetermined rotational direction;
- providing a reciprocating knife positioner having a lifting block and a reciprocating block movably attached to the lifting block;
- moving the lifting block until an outer knife attached to the reciprocating block is in a cutting position, wherein the outer knife overlaps an inner knife positioned inside the pipe and punctures the pipe;
- radially reciprocating the reciprocating block with respect to the pipe when the outer knife is in the cutting position, and maintaining the inner and outer knives in an overlapping relationship while rotating the pipe between the overlapping inner and outer knives;
- and
- retracting the outer knife after the pipe has completed a revolution.
A method of cutting a spirally formed pipe comprising the steps of:
- continuously rotating a spirally formed pipe in a predetermined rotational direction;
- moving a non-rotatable outer knife from a standby position to a cutting position, wherein the outer knife overlaps a non-rotatable inner knife and punctures the pipe;
- maintaining the outer knife in a fixed radial position with respect to the pipe while the inner and outer knives are in the cutting position, wherein the inner and outer knives remain in a fixed overlapping position while the pipe rotates;
- and
- retracting the outer knife after the pipe has completed a revolution.
Dependencies are inferred from the claim text.