Pipe fitters lay out tool

#The present invention relates to tools used In the fabrication of pipe and more particular to a simple tool used for generating geometry and layout lines required for precise cutting and joining of pipe sections in preparation for welding.

#Oftentimes, due to pipe size, complexity of required joint intersect angles and final configuration of a piping system or run as it is commonly referred to, it is impractical to join the various sections of pipe by means of threaded ends requiring joints and pipe sections to be mated by annular weld beads.

#To insure proper fit and joint integrity of pipe sections that intersect at various angles forming a particular joint for welding, each of the pipe sections or components are required to be cut at a specific geometry that will provide for proper fit of one to the another. The specific geometry of the cut required on either of the pipe sections is dependent upon the size and or respective size differences of each pipe component and angle of intersection required between each of the pipe components.

#FIGS. 1a and 1b show frame profile and frame top and bottom surface details

#FIGS. 2a and 2b show blow-up assembly view of tool and extension

#FIGS. 3a and 3b show common pipe joining details

#Referring to FIGS. 1a and b where 1a shows the top surface and 1b shows the bottom surface of the preferred embodiment of Pipe fitters layout tool, here in referred to as the tool 100. Tool 100 is comprised of a one piece frame 1 fabricated from lightweight material such as aluminum approximately ⅜″ thick.

#Said one piece frame 1 being of irregular geometry can best be described by identifying three basic geometric shapes that comprise the shape of frame 1. The shapes are, a half circle consisting of two quadrants, an elongated rectangle and an Isosceles triangle. It should be noted for the purpose of this description that three shapes are used to define the single overall shape of frame 1. The shapes are directly adjacent to each other and relative to two lines that are perpendicular to each other. The two lines are, the longitudinal centerline 4 of frame 1 and datum line 5 which crosses substantially perpendicular to longitudinal centerline 4 at point 6. The first basic shape will best be described as a half circle of approximately 2⅝ inch radius here in referred to as radius end 7 of frame 1. The half circle shape of radius end 7 is generated from point 6 located at the intersection of datum line 5 and longitudinal center line 4 of frame 1. Datum line 5 also defines the major diameter of the half circle shape of radius 7 For further descriptive clarification, radius end 7 is further divided into quadrants 8 and 9 by longitudinal center line 4 of frame 1. A second basic shape used in the description of frame 1 is a rectangle with a width or minor dimension of approximately 2¾″ and 14″ long measuring from end 11 to end 12 which is directly adjacent to datum line 5. This rectangle will here in be referred to as blade 10. Blade 10 comprises one physical end 11, one end adjacent to and defined by datum line 5 here in referred to as opposite end 12, a straight edge 13 and a back edge 14. Straight edge 13 and back edge 14 are parallel to each other. Straight edge 13 lies substantially on a portion of longitudinal center line 4 of frame 1. End 12 of blade 10 is adjacent to the portion of datum line 5 which serves as on side of quadrant 8. A third basic shape that helps to clarify the overall geometry of frame 1 is an Isosceles triangle here in referred to as tang 15. The Isosceles triangle defining tang 15 is oriented with one of the equal sides 16 directly adjacent to datum line 5 which along with longitudinal center line 4 define the two straight sides of quadrant (9). Side 17, being the other equal side of the Isosceles triangle that forms tang 15 extends from a point tangent to radius edge 21 where radius edge 21 in quadrant 9 of radius end 7 intersects with datum line 5 and terminates at tip 18 on tang 15. The third side of the Isosceles triangle that defines tang 15 is inside edge 19 which extends from tang tip 18 back to point 6 on center line 4 of frame 1 forming angle 20 which is approximately 45 degrees. Referencing radius end 7. Pocket 33 comprising a 1¾ inch circle, approximately ⅛ inch deep countersunk into top surface 2 of radius end 7 in frame 1 is provided to receive protractor bubble level 22 as shown in FIG. 2 Pocket 33 to be centered on longitudinal centerline 4 at a point of equal distance between point 6 of radius end 7 and where frame centerline 4 meets radius edge 21 of radius end 7. Threaded protractor mounting hole 34 to be substantially centered in pocket 33.

#Referring now to FIGS. 2, 4a and 4b which in combination shows protractor mounting hole 34 in pocket 33 to be threaded to mate with retaining screw 35 securing Protractor bubble level 22 in pocket 33. Protractor bubble level 22 provides for rotational orientation of tool 100 when used in a vertical plane for angular marking of pipe face 81 as shown in FIG. 3. Protractor bubble level 22 comprises a degree plate 24 and a liquid bubble assembly 23 substantially fixed to degree plate 24. Bubble assembly 23 is provided with centering lines 25 and 26 which indicate when Bubble 27 is centered in bubble assembly 23. Degree plate 24 provides indicia 28 for indicating angularity between protractor bubble level 22 and reference marks 29 locked directly adjacent to pocket 33 substantially on longitudinal center line 4 of radius end 7 on frame 1. Indicia 28 comprises degree marks with zero degrees indicia line 30 being perpendicular to level tube center line 31. Indicia 28 to be oriented around degree plate 24 and provide for one degree increments in either direction from zero degrees 30 to 90 degrees. It should be noted that although the indicia in this illustration is carried on degree plate 24 it could instead be located on top surface 2 of frame 1 around the parameter of pocket 33 and reference marks 29 placed on degree plate 24.