Abstract:
A scribe and a method of using the scribe to mark a cutting guide on one conduit, while also using a second conduit as a guide, is disclosed. The scribe includes a pivot which rests on the outer surface on one conduit. The scribe also includes a scribe element which engages the outer surface of the one conduit. The scribe is moved along the outer surfaces of the two conduits and makes a mark on the one conduit that precisely follows the shape and size of the second conduit. The one conduit is cut along the mark and the second conduit will precisely and accurately fit to the one conduit. A method of coupling two conduits using this scribe is also disclose.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the general art of geometric instruments, and to the particular field of scribers used on curved surfaces. 
     2. Discussion of the Related Art 
     Pipe welders are often called upon to cut one conduit to engage a second conduit. The term “conduit” will be used to cover pipes, tubes and other such curved elements. At the present time, this procedure is carried out using a template. The template is formed by a template maker after the pipe welder has supplied dimensions. The template is then placed on a conduit to be cut and the conduit is cut. 
     This process requires the pipe fitter to wait until the template is supplied before proceeding with his work. This wait is wasteful of the pipe fitter&#39;s time and can be costly to his employer due to the down time of the pipe fitter. The wait can be anywhere from a few minutes to hours, or even days, depending on the circumstances. 
     Therefore, there is a need for a means and a method for defining a cutting guide mark on a conduit which will be joined to another conduit adjacent to the cut made along the cutting guide mark without requiring use of a template. 
     Often, the pipe fitter is in a location that is not convenient for obtaining a template. Not only does this increase the time required to obtain a template, it also increases the difficulty in obtaining the template. 
     Therefore, there is a need for a means and a method for in situ defining a cutting guide mark on a conduit which will be joined to another conduit adjacent to the cut made along the cutting guide mark without requiring use of a template. 
     Often, templates formed for one conduit may not be as accurate and as precise as possible for another conduit. This may be caused by manufacturing tolerances or environmental conditions or the like. 
     Therefore, there is a need for a means and a method for defining a cutting guide mark on a conduit which will be joined to another conduit-adjacent to the cut made along the cutting guide mark without requiring use of a template yet which can accurately and precisely mark each conduit. 
     PRINCIPAL OBJECTS OF THE INVENTION 
     It is a main object of the present invention to provide a means for defining a cutting guide mark on a conduit which will be joined to another conduit adjacent to a cut made along the cutting guide mark without requiring use of a template. 
     It is another object of the present invention to provide an in situ means for defining a cutting guide mark on a conduit which will be joined to another conduit adjacent to a cut made along the cutting guide mark without requiring use of a template. 
     It is a specific object of the present invention to provide a scribe for defining a cutting guide mark on a conduit which will be joined to another conduit adjacent to a cut made along the cutting guide mark without requiring use of a template. 
     It is another object of the present invention to provide a means for defining a cutting guide mark on a conduit which will be joined to another conduit adjacent to a cut made along the cutting guide mark without requiring use of a template and which will accurately and precisely define the cutting guide mark. 
     It is another object of the present invention to provide a method for defining a cutting guide mark on a conduit which will be joined to another conduit adjacent to a cut made along the cutting guide mark without requiring use of a template. 
     SUMMARY OF THE INVENTION 
     These, and other, objects are achieved by a conduit marking scribe comprising a body; a pivot unit on one end of the body, the pivot unit including a wheel which is adapted to contact the outer surface of a first conduit which will be engaged with a second conduit after the second conduit has been cut; and a scribe unit movably mounted on the body, the scribe unit including a scribe element which includes a distal end and which is movable between a first position having the distal end located inside the scribe unit and a second position having the distal end located outside the scribe unit with the distal end in position to contact the outer surface of the second conduit, and a biasing element which biases the scribe element toward the second position. 
     The objects are also achieved by a method of marking a conduit which includes providing the scribe unit described above, temporarily attaching one end of the second conduit to the outer surface of the first conduit at a location where the second conduit will be joined to the first conduit; contacting the wheel against the outer surface of the first conduit; contacting the wheel against the outer surface of the first conduit, contacting the wheel against the outer surface of the first conduit; locating the scribe unit against the outer surface of the second conduit; contacting the distal end of the scribe unit against the outer surface of the first conduit; and marking the second conduit by moving the scribe unit with respect to the first conduit and with respect to the second conduit so the distal end of the scribe unit engages and marks the second conduit while the wheel of the pivot unit remains in contact with the outer surface of the first conduit and moves over the outer surface of the first conduit. 
     The scribe will be used in place and thus the user need not wait for a template and will be able to define cutting guide marks that are accurate and precise for the particular job. In this way, if one particular job is slightly different from another, the scribe and method embodying the present invention can accommodate such difference and still provide an accurate and precise cutting guide mark. The scribe embodying the present invention is very easy to transport and thus can be available to the worker at any time and anywhere it is needed. 
     Still further, the scribe embodying the present invention is easily adaptable for use with additional geometric instruments, such as a ruler. However, the scribe embodying the present invention can be used by itself without requiring any additional instruments for its proper use. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     FIG. 1 is a perspective view of a scribe embodying the present invention. 
     FIG. 2 is a is an elevational view taken along line  2 — 2  of FIG.  1 . 
     FIG. 3A illustrates an initial step of temporarily attaching one conduit to another in the method of using the scribe as embodied in the present invention. 
     FIG. 3B illustrates a step of marking one conduit using the other conduit as a guide as embodied in the present invention. 
     FIG. 3C shows one conduit attached to the other. 
     FIG. 3D is a side elevational view of a conduit after it has been marked and cut in preparation for attaching the conduit with another conduit as embodied in the present invention. 
     FIG. 4 is a perspective view showing one conduit attached to the other. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Other objects, features and advantages of the invention will become apparent from a consideration of the following detailed description and the accompanying drawings. 
     Referring to FIGS. 1 and 2, it can be understood that the present invention is embodied in a conduit marking scribe  10  that can be used to precisely and accurately place a cutting guide mark on a conduit and will thereby eliminate the need for a template. Scribe  10  comprises a body element  12 . Body element  12  includes a first end  14 , a second end  16 , and a longitudinal axis  18  which extends between the first end  14  of the body element  12  and the second end  16  of the body element  12 . 
     The body element  12  further includes a first side  20 , a second side  22 , and a transverse axis  24  which extends between the first side  20  of the body element  12  and the second side  22  of the body element  12 . 
     The body element  12  further includes a first surface  26 , a second surface  28 , and a thickness dimension  30  which extends between the first surface  26  of the body element  12  and the second surface  28  of the body element  12 . 
     A slot  32  is defined in the body element  12  and extends from adjacent to the first end  14  of the body element  12  to adjacent to the second end  16  of the body element  12 ; the slot  32  also extends from the first surface  26  of the body element  12  to the second surface  28  of the body element  12 . 
     A pivot unit  40  is located on the second end  16  of the body element  12 . Pivot unit  40  is adapted to contact and move along the outer surface of a first conduit C 1  (see FIG. 4) which will be engaged with a second conduit C 2  after the second conduit has been cut to accommodate the first conduit. 
     Pivot unit  40  includes a mounting ear  42  on the second end  16  of the body element  12  and a wheel  44  rotatably mounted on the ear  42  to rotate in a plane containing the transverse axis  24  of the body element  12 . Wheel  44  has an outer circumference  46  and rotates on the mounting ear  42  clockwise CW and counterclockwise CCW with respect to the first and second sides  20 ,  22  of the body element  12 . Pivot unit  40  further includes knurling  47  on the outer circumference  46  of the wheel  44 , and a center hole  48  which is defined through the wheel  44  and through the mounting ear  42 . 
     A scribe unit  50  is movably mounted on the body element  12 , and is shown in FIG.  2 . Scribe unit  50  includes a frame  52  having a first surface  54 , a second surface  56 , and a thickness dimension  58  that extends in the direction of the thickness dimension  30  of the body element  12  when the first surface  54  of the frame  52  is positioned to abut the second surface  28  of the body element  12  (see FIG.  1 ). Frame  50  has a hole  60  defined therethrough with the hole  60  being oriented to extend in the direction of the thickness dimension  30  of the body element  12  when the first surface  54  of the frame  52  is in contact with the second surface  28  of the body element  12 . A counterbore  62  is defined in the second surface  56  of the frame  52  adjacent to the hole  60  defined through the frame  52 . 
     Scribe unit  50  further includes a bored bolt  70  which includes a head end  72  located in the counterbore  62  defined in the second surface  56  of the frame  52  when the bored bolt  70  is in place on the frame  52  as shown in FIG. 2. A bolt body  74  extends from the head  72  of the bored bolt  70  through hole  60  defined through the frame  52  to extend through slot  32  defined in the body element  12  when the scribe unit  50  is in place mounted on the body element  12  as indicated in FIGS. 1 and 2. The bored bolt  70  further includes a second end  76  and an outer surface  78  on the bored bolt body  74 . A bore  80  is defined in the bored bolt body  74  and extends from the head  72  of the bored bolt  70  to the second end  76  of the bored bolt  70 . Bored bolt  70  has an inner surface  82  located adjacent to the bore  80  defined in the bored bolt body  74 . A screw thread  84  is defined in the outer surface  78  of the bored bolt body  74 . 
     An annular washer  90  has a first surface  92  and a second surface  94 . Second surface  94  of the annular washer  90  is located to contact the first surface  54  of the frame  52  when the annular washer  90  is in place on the frame  52  as shown in FIG.  2 . The annular washer  90  has a hole  96  defined therethrough. Hole  96  extends from the first surface  92  of the washer  90  to the second surface  94  of the washer  90  and is aligned with hole  60  defined through the frame  52  when the washer  90  is in place as shown in FIG.  2 . 
     An annular nut  100  has a first surface  102  and a second surface  104 , with the second surface  104  of the annular nut  100  contacting the first surface  92  of the annular washer  90  when the washer  90  and the nut  100  are in place as shown in FIG.  2 . Nut  100  has a hole  106  defined therethrough from the first surface  102  of the nut  100  to the second surface  104  of the nut  100 . Hole  106  is aligned with hole  96  defined through the washer  90  and is aligned with hole  60  defined through the frame  52  when the nut  100  and the washer  90  are in place on the frame  52  as shown in FIG.  2 . Nut  100  has a screw thread  110  defined thereon adjacent to the hole  106  defined through the nut  100 . The screw thread  110  on the nut  100  threadably engages the screw thread  84  on the bored bolt  70  when the bored bolt  70  and the nut  100  are in place, on the frame  52 . 
     A bored knob  120  is located on the bored bolt  70  when the knob  120  is in place as shown in FIG.  2 . Bored knob  120  includes a body  122 , a first end  124  on the body  122  of the knob  120 , and a second end  126  on the body  122  of the knob  120 . First end  124  of the bored knob  120  is spaced apart from first surface  102  of nut  100  to define a gap  130  between the bored knob  120  and the nut  100  when the knob  120  and the nut  100  are in place on the bored bolt  70  as shown in FIG.  2 . Body element  12  is interposed between the nut  100  and the knob  120  when the scribe unit  50  is in place on the body element  12  with the first surface  26  of the body element  12  in contact with the first end  124  of the knob  120  and the second surface  28  of the body element  12  in contact with the first surface  102  of the nut  100  whereby the scribe unit  50  is held in place on the body element  12  through frictional engagement with the body element  12 . 
     A blind-ended bore  140  is defined in the bored knob  120 . The blind-ended bore  140  extends from the first end  124  of the knob  120  toward the second end  126  of the knob  120  and is aligned with the hole  106  defined through the nut  100  when the knob  120  and the nut  100  are in place on the bored bolt  70  as shown in FIG.  2 . 
     A screw thread  142  is defined on the bored knob  120  adjacent to the blind-ended bore  140 . The screw thread  142  on the knob  120  and the screw thread  84  on the bored bolt  70  are threadably engaged with each other when the knob  120  is in place on the bolt  70  as shown in FIG.  2 . 
     A compression spring  150  is located inside the blind-ended bore  140  and has a first end  152  abutting the knob  120  adjacent to the blind-ended bore  140  and a second end  154  located inside the bore  106  defined through the bored nut  100  when the knob  120  is in place on the bored bolt  70  and the spring  150  is in place in the blind-ended bore  140  as shown in FIG.  2 . 
     A scribe element  160  is movably positioned inside the bore  80  of the bored bolt  70  when the scribe element  160  is in place as shown in FIG.  2 . The scribe element  160  includes a proximal end  164  in abutting contact with a second end of the spring  150  when the scribe element  160  is in place in the bore of the bored bolt  70  and a distal end  166  which is located adjacent to the head  72  of the bored bolt  70  when the scribe element  160  is in place. The scribe element  160  moves between a first position in which the distal end  166  of the scribe element  160  is located inside the bore  80  of the bored bolt  70  and a second position shown in FIG. 2 in which the distal end  166  of the scribe element  160  is located outside the bore  80  of the bored bolt  70 . The spring  150  biases the scribe element  160  toward the second position. The distal end of the scribe element is adapted to contact outer surface S 2  of second conduit C 2  while the pivot unit  40  is in contact with first conduit C 1 . 
     Referring to FIGS. 3A-4, it can be understood that the present invention is also embodied in a method of scribing a conduit, which comprises marking a conduit which includes providing the scribe unit  50  described above, temporarily attaching one end E, as by a tack weld W, of the second conduit to the outer surface of the first conduit at a location L where the second conduit will be joined to the first conduit as indicated in FIG. 3A; contacting the wheel  44  against the outer surface S 1  of the first conduit, the knurling  47  providing a good grip on the conduit; locating the scribe unit  50  against outer surface S 2  of the second conduit; contacting the distal end  166  of the scribe unit  50  against outer surface S 1  of the first conduit; and marking the second conduit by moving the scribe unit  50  with respect to the first conduit and with respect to the second conduit so the distal end  166  of the scribe unit  50  engages and marks the second conduit while the wheel  44  of the pivot unit  40  remains in contact with the outer surface of the first conduit and moves over the outer surface of the first conduit as indicated in FIG.  3 B. As will be understood by those skilled in the art based on the teaching of this disclosure, the distal end  166  of the scribe unit  50  is forced out of the blind-ended bore  140  by the biasing of the spring  150  and is forced out far enough to remain in contact with the curved outer surface of conduit C 2  even when that outer surface is located farthest away from the scribe unit  50 . The marking process is repeated for as many cuts as will be made in the second conduit. There are two cuts made in the second conduit in FIGS. 3A and 3B, and the final product for conduit C 2  is indicated in FIG.  4 . Conduit C 1  will be joined to conduit C 2  by weld W 2 . 
     As indicated in FIG. 3C, the first and second conduits are then joined together along the cuts made in the second conduit. The temporary joining of the two conduits can be effected by tack welds, and the final joining of the two conduits can be effected by welding. 
     The final product is indicated in FIG. 4 with the first and second conduits joined together. 
     While the conduit marking device described above can be used without any other instruments, if desired, the conduit marking device  10  can also be used in conjunction with another instrument, such as a ruler R shown in FIG.  1 . 
     It is understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangements of parts described and shown.