Method and device for forming a branch connection in a pipe

A device for forming a branch connection in a pipe, the device comprising:

• (a) a saddle member having a fluid passage in it and arranged to be secured to the surface of the pipe with an end of the fluid passage closed by said pipe surface when the saddle member is placed thereon, said saddle member having a groove therein for longitudinal reception of a portion of the length of the pipe;
• (b) sealing means for forming a fluid-tight seal between the surface of the pipe and the adjacent surface of the saddle member around the end of the passage;
• (c) a backing member having a groove therein for longitudinal reception of a portion of the length of the pipe, the groove in the backing member opposing the groove in the saddle member with said portion of the pipe received in the opposed grooves;
• (d) means to urge the saddle member and backing member toward one another with the portion of the pipe received in the opposed grooves;
• (e) a cutting element carried by one of the members and capable of rotation relative to such member about an axis transverse to the pipe axis, said cutting element having a cutting edge offset from said axis of rotation, said cutting element being further capable of simultaneous movement toward the axis of the pipe for causing said cutting edge to progressively cut through the wall of the pipe in a circular path;
• (f) said axis of rotation of said cutting element being spaced from said pipe axis so that as said cutting edge progressively cuts around said path, it will cut from a beginning at one point on said path to an end at another point on said path spaced from first point, with a relatively small part of said wall uncut to form a part-circular tongue joined to the pipe wall by a narrow web between said points, the cutting edge accordingly forming a cut in the pipe which starts at the side thereof at which the axis of rotation of the cutting element is spaced from the pipe axis, and continues through the pipe wall and exits the pipe at the same side thereof, but spaced from the entry to the cut;
• (g) the cutting element being capable, on further movement toward said pipe axis, of depressing the tongue inwardly while leaving it attached to the remainder of the pipe by the narrow web.

A method of forming a branch connection in a fluid carrying pipe by squeezing a longitudinal portion of the pipe between a groove in a saddle member and an opposed groove in a backing member and turning in one of said members a cutting element sealingly rotatable in a fluid passageway in that member, the cutting element being turned about an axis transverse to the pipe axis, the cutting element having a cutting edge spaced from the axis of rotation of the cutting element and the cutting element simultaneously moving toward the axis of the pipe as it rotates forcing the cutting edge to progressively cut through the wall of the pipe in a circular path, the axis of rotation of said cutting element being offset from said pipe axis so that as the cutting edge progressively cuts around the path it will cut from a beginning at one point on said path to an end on another point on said path spaced from said first point with a relatively small part of said wall uncut to form a part-circular tongue joined to the remainder of the pipe wall by a narrow web between said points, the cutting edge accordingly forming a cut in the pipe which starts at the side thereof at which the axis of rotation of the cutting element is spaced from the pipe axis, and continues through the pipe wall and exits the pipe at the same side thereof, but spaced from the entry to the cut, further operation of the cutting element depressing the tongue inwardly while leaving the tongue attached to the pipe by said narrow web.