Apparatus for cutting hollow pipes

An apparatus for cutting pipe which is spirally formed from a flat strip, whereby the pipe moves in an axial direction and rotates while it is being formed, comprising:

• first knife means to be positioned inside the pipe;
• second knife means to be positioned outside the pipe;
• means for reciprocating the second knife means in a direction toward the first knife means;
• means for moving the second knife means to a cutting position where it will reciprocate into and out of an overlapping relationship with the first knife means;
• and
• guide means for allowing the first and second knife means to move in the axial direction of the pipe when the second knife means is in the cutting position, so that during a cutting operation the second knife means will reciprocate and overlap the first knife means or the pipe moves axially and rotates between the first and second knife means.

For use with a machine for producing spiral seamed hollow pipe from a metal strip including drive means for feeding the strip through the machine, means for forming the strip into a spiral cylinder so that the outer edges of the strip are adjacent each other, and means for joining the adjacent edges to produce a spiral seamed pipe, whereby the pipe moves in an axial direction and rotates while it is being formed, a pipe cutting apparatus comprising:

• first knife means to be positioned inside the pipe;
• second knife means to be positioned outside the pipe;
• means for reciprocating the second knife means in a direction toward the first knife means;
• means for moving the second knife means to a cutting position where it will reciprocate into and out of an overlapping relationship with the first knife means;
• and
• guide means for allowing the first and second knife means to move in the axial direction of the pipe when the second knife means is in the cutting position, so that during a cutting operation the second knife means will reciprocate and overlap the first knife means as the pipe moves axially and rotates between the first and second knife means.

An apparatus for cutting pipe which is spirally formed from a flat strip, whereby the pipe moves in an axial direction and rotates while it is being formed, comprising:

• first and second knife means to be positioned inside the pipe;
• third and fourth knife means to be positioned outside the pipe, the third knife means positioned opposite the first knife means and the fourth knife means positioned opposite the second knife means;
• first reciprocating means for reciprocating the third knife means in a direction toward the first knife means;
• second reciprocating means for reciprocating the fourth knife means in a direction toward the second knife means;
• first moving means for moving the third knife means to a first cutting position where it will reciprocate into and out of an overlapping relationship with the first knife means;
• second moving means for moving the fourth knife means to a second cutting position where it will reciprocate into and out of an overlapping relationship with the second knife means;
• and
• guide means for allowing the first, second, third and fourth knife means to move in the axial direction of the pipe when the third and fourth knife means are in the first and second cutting positions, whereby the first and third knife means will cooperate to cut the pipe when the third knife means reciprocates and overlaps the first knife means and the second and fourth knife means will cooperate to cut the pipe when the fourth knife means reciprocates and overlaps the second knife means, as the pipe moves axially and rotates between the first and third knife means and between the second and fourth knife means.

An apparatus for cutting pipe which is spirally formed from a flat strip, whereby the pipe moves in an axial direction and rotates while it is being formed, comprising:

• first and second knife means mounted on a boom to be positioned inside the pipe, the first and second knife means each having a cutting edge to be positioned close to the inside surface of the pipe and pointing in opposite directions;
• third and fourth knife means to be positioned outside the pipe, the third knife means having a cutting edge positioned opposite of the cutting edge of the first knife means, and the fourth knife means having a cutting edge positioned opposite the cutting edge of the second knife means;
• first reciprocating means for reciprocating the third knife means in a direction toward the first knife means;
• second reciprocating means for reciprocating the fourth knife means in a direction toward the second knife means;
• first moving means for moving the third knife means to a first cutting position where its cutting edge will reciprocate into and out of an overlapping relationship with the cutting edge of the first knife means;
• second moving means for moving the fourth knife means to a second cutting position where its cutting edge will reciprocate into and out of an overlapping relationship with the cutting edge of the second knife means;
• and
• guide means for allowing the first, second, third and fourth knife means to move in the axial direction of the pipe when the third and fourth knife means are in the first and second cutting positions, whereby the first and third knife means will cooperate to cut the pipe when the cutting edge of the third knife means reciprocates and overlaps the cutting edge of the first knife means and the second and fourth knife means will cooperate to cut the pipe when the cutting edge of the fourth knife means reciprocates and overlaps the cutting edge of the second knife means, as the pipe moves axially and rotates between the first and third knife means and between the second and fourth knife means.