Pulling member

1. A two piece cylindrical pulling member for forming a branched opening with a shoulder in a side wall of a malleable pipe when pulled by a pulling rod, the pulling member having a radius and a depth and comprising:

(a) a base having: (i) a square portion having an upwardly facing interior face, a central opening, front and rear opposed ends, and a depth about 50 percent of the depth of the pulling member; and (ii) two upwardly extending circular segment portions at the front and rear opposed ends with a depth equal to the depth of the pulling member, the circular segments defining parallel opposed chords and having an apothem about 71 percent of the radius of the pulling member and having an arc length of about 90 degrees; and

(b) a top having: (i) a square portion having a downwardly facing interior face, a central opening, left and right opposed ends, and a depth about 50 percent of the depth of the pulling member; and (ii) two downwardly extending circular segment portions at the left and right opposed ends with a depth equal to the depth of the pulling member, the circular segments defining parallel opposed chords and having an apothem about 71 percent of the radius of the pulling member and having an arc length of about 90 degrees, such that the top fits onto the base with the interior face of the base and the interior face of the top in contact to form a cylinder.

2. The pulling member of claim 1 additionally comprising: (c) a means for attaching the pulling member to a pulling rod.

3. The pulling member of claim 2 wherein the base has a central circular threaded opening and the top has a central unthreaded circular opening.

4. The pulling member of claim 3 wherein the base has a central internally threaded sleeve portion extending upwardly from the face.

5. An assembly for forming a branched opening with a shoulder in a side wall of a malleable pipe, the assembly comprising:

(a) a two piece pulling member having a radius and a depth and comprising: (i) a base having: (1) a square portion having an upwardly facing interior face, a central opening, front and rear opposed ends, and a depth about 50 percent of the depth of the pulling member; and (2) two upwardly extending circular segment portions at the front and rear opposed ends with a depth equal to the depth of the pulling member, the circular segments defining parallel opposed chords and having an apothem about 71 percent of the radius of the pulling member and having an arc length of about 90 degrees; and (ii) a top having: (1) a square portion having a downwardly facing interior face, a central opening, left and right opposed ends, and a depth about 50 percent of the depth of the pulling member; and (2) two downwardly extending circular segment portions at the left and right opposed ends with a depth equal to the depth of the pulling member, the circular segments defining parallel opposed chords and having an apothem about 71 percent of the radius of the pulling member and having an arc length of about 90 degrees, such that the top fits onto the base with the interior face of the base and the interior face of the top in contact to form a cylinder; and

(b) a pulling tool subassembly comprising: (i) a pulling rod for attachment to the pulling member; and (ii) a pulling tool for applying a pulling force to the pulling rod to pull the pulling member through a hole in a side wall of a malleable pipe to form a branched opening with a shoulder.

6. The assembly of claim 5 wherein the base of the pulling member has a central circular threaded opening, the top of the pulling member has a central circular unthreaded opening, and the pulling rod has a threaded distal end that mates with the central threaded opening of the base.

7. The assembly of claim 5 additionally comprising: (c) a cutting tool subassembly comprising: (i) a blade for cutting a hole in the side wall of a malleable pipe; and (ii) a motor for moving the blade.

8. The assembly of claim 7 additionally comprising a support for resting upon the pipe and for supporting either the pulling tool subassembly or the cutting tool subassembly, the support comprising two transverse saddles and two longitudinal rails.

9. A method for forming a branch opening with a shoulder in a side wall of a malleable pipe, the method comprising:

(a) obtaining a malleable pipe with a hole in a side wall;

(b) obtaining a two piece pulling member having a radius and a depth and comprising: (i) a base having: (1) a square portion having an upwardly facing interior face, a central circular opening, front and rear opposed ends, and a depth about 50 percent of the depth of the pulling member; and (2) two upwardly extending circular segment portions at the front and rear opposed ends with a depth equal to the depth of the pulling member, the circular segments defining parallel opposed chords and having an apothem about 71 percent of the radius of the pulling member and having an arc length of about 90 degrees; and (ii) a top having: (1) a square portion having a downwardly facing interior face, a central circular opening, left and right opposed ends, and a depth about 50 percent of the depth of the pulling member; and (2) two downwardly extending circular segment portions at the left and right opposed ends with a depth equal to the depth of the pulling member, the circular segments defining parallel opposed chords and having an apothem about 71 percent of the radius of the pulling member and having an arc length of about 90 degrees, such that the top fits onto the base with the interior face of the base and the interior face of the top in contact to form a cylinder; and;

(c) inserting the base of the pulling member through the hole in the pipe;

(d) inserting the top of the pulling member through the hole in the pipe;

(e) fitting the top of the pulling member onto the base of the pulling member with the interior face of the base and the interior face of the top in contact to form the pulling member;

(f) attaching a pulling rod to the pulling member; and

(g) pulling on the pulling rod to pull the pulling member through the hole to form a branched opening with a shoulder.

10. The method of claim 9 wherein the base of the pulling member has a central threaded opening, the top of the pulling member has a central opening, and the pulling rod has a threaded distal end that mates with the central threaded opening of the base.

11. The method of claim 9 wherein the pulling rod is part of a pulling tool subassembly comprising a motor, wherein the pulling tool subassembly is mounted onto a support resting on the pipe, and wherein the support comprises two transverse saddles and two longitudinal rails.