Abstract:
A torch cutting tool has a clamp that is attached to a workpiece with the clamp having a rotating platform with an attached first latch member. A second latch member is attached to a track with a moveable carriage on which is mounted a positioning arm with a torch holder. After the clamp is attached to the workpiece, the second latch member is quickly latched to the first latch member to effect quick and simple setup. A cam follower, a second rotating platform, a second positioning arm, a covered track, a rotating base plate and metered fuel and oxygen supplies make the tool simple and easy to use.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Applications No. 60/335,666 filed on Oct. 31, 2001 and 60/415,312 filed on Sep. 30, 2002, both of which are incorporated here by reference as if completely written herein. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms as provided for the terms of contract No. N00014-98-2-0010, subcontract No. 105 awarded by the United States Office of Naval Research. 
    
    
     BACKGROUND 
     As background, ships are typically made in transverse sections that are joined together in dry dock. These sections have horizontal steel ribs (stiffeners) that are attached to the walls (bulkhead) of the ship section. These stiffeners, are also known as erection beams or bulb-flat stiffeners and are used to provide support to and prevent buckling of the panels used in shipbuilding. The bulb-flat stiffeners are welded at their edge to ship sections (portions of the hull) prior to the attachment of the transverse sections to each other. They are also used with interior bulkheads (vertical walls) as well as with deck plating (flooring). For the hull and bulkheads, stiffeners are attached to the hull and bulkheads in a vertical orientation. When used with decking, they are used in a horizontal orientation. Bulb-flat stiffeners are in many respects analogous to the wall studs and floor joists typically used in home construction. 
     When a ship section is made, the bulb-flat stiffeners extend past the ends of the wall section and must be trimmed in the ship building process, i.e., in the assembly of the ship sections. In the ship building process, a new section is brought into place next to the end of the previously assembled sections and the amount of extending bulb-flat stiffener that needs to be trimmed off is marked for cutting. The new section is moved away from the assembled sections and a cutting torch (oxygen and gas or oxygen and acetylene) is then used to cut off the excess portion of the stiffener. After the ends of the bulb-flat stiffeners are trimmed to the appropriate length, the edge of the new section is butted against the edge of the previously assembled sections of the ship that has already been welded in place and the two abutting sections, i.e., the abutting edges (ends) of the hull and the bulb-flat stiffeners are welded together. 
     In present day practice, the bulb-flat stiffeners are trimmed entirely by hand, i.e., a section assembler takes a cutting torch and trims off the excess portion of stiffener by means of a free-hand, visual inspection (“eye-ball”) method. Unfortunately the work place environment is typically not worker friendly in that the worker doing the bulb-flat cutting often works more than a hundred feet in the air on temporary scaffolding in a dark and dirty environment that is not at all conducive to making straight and accurate cuts. As a result, the free-hand trimming of excess bulb flat ends can result in large gaps between adjacent bulb-flat stiffener ends when the sections are brought into position for final assembly. It is not unusual for it to take an hour or longer to fill in the gaps between the ends of the bulb-flat stiffeners when the ends are welded together. 
     Although some efforts have been made to mechanize cutting of various members in other industries, none of those devices meet the needs of the ship building industry. For example, U.S. Pat. No. 5,160,549 (Murphy) discloses a cam follower device for cutting angled finned tubes. This device relies on completely supporting the work piece in the cutting machine. U.S. Pat. No. 3,190,628 (Litzka) describes a device for cutting center sections from I beams but, here again, the device relies on supporting and/or clamping the device and the work piece to a solid work bed. U.S. Pat. No. 4,180,248 (Benko) is directed to a sill cutting unit but here the machine is supported independently of the work piece. In all three patents, the units are very large and do not provide the portability needed for use in the ship building arts. U.S. Pat. No. 4,471,948 (Holmes) is directed to a cutting unit that is attached to the work piece but in this instance the torch travels in an arc about a pivot pin with a cam used to maintain the cutting torch at a relatively constant distance from the work piece. 
     None of these devices teach or suggest a portable unit for making straight line bevel cuts with provisions for cutting a large bulb member at one edge of the work piece that must be fashioned into a scoop to allow for high-quality and high-strength welds required in the ship building arts. Further none of these references teach how such a device might be adapted for the varying cutting angles required in joining the angled sections of a ship or aligning the torch for cutting at but not into the attached hull of the ship. None of these references teach a device by which the welding torch can be aligned repetitively at various angles with a high degree of accuracy. None of these reference teach how a cutting torch can be set to ignite and weld at a predetermined optimal gas and oxygen level without constant adjustment of the cutting torch each time the unit is used. 
     As such, it is an object of the prevent invention to provide a cutting torch unit capable of cutting a flat-bulb stiffener using a single drive unit. 
     It is another object of the present invention to provide a cutting torch unit capable of repetitively cutting a beveled edge on a flat-bulb stiffener. 
     It is another object of the present invention to provide a cutting torch unit capable of cutting a flat-bulb stiffener at the point it meets an attached plate without damage to the attached plate. 
     It is another object of the present invention to provide a cutting torch unit capable of cutting a flat-bulb stiffener at an angle necessary for joining angled sections of a ship. 
     It is another object of the present invention to provide a cutting torch unit capable of being quickly and accurately secured to the work piece for precise cutting. 
     It is yet another object of the present invention to provide a cutting torch unit with a torch that is maintained at an optimal level of cutting efficiency without repetitive adjustment of fuel and oxygen flows each time a cut is made. 
     It is another object of the present invention to provide a cutting torch unit that is capable of forming a scoop in the bulb end of a flat-bulb stiffener for optimal welding conditions. 
     It is another object of the present invention to provide a cutting torch unit that is quickly broken down into portable sections for meeting adverse shipyard work conditions. 
     It is another object of the present invention to provide a torch holder with an alignment mechanism and angle indica that allow for quick and accurate alignment of the cutting torch. 
     It is a further object of the present invention to provide a cutting tool that is easy and convenient to carry, handle, and manipulate under shipyard conditions, that is, in cutting bulb-flat stiffeners using scaffolding extending upward 150 feet or more in what is typically a dark and debris laden environment. 
     Another object of the present invention provides consistent, high quality weld joint parations in a very short time. 
     It is yet another object of the present invention to provide a beveled edge and scoop area at allow for rapid and convenient access to the joint region during the welding process. 
     Another object of the present invention is to provide a cutting torch assembly for cutting a variety of structural materials including T- and I-beams. 
     It is another object of the present invention to provide a means for quickly positioning and moving the track of a track and carriage system with respect to its supporting assembly. 
     The foregoing and other objects, features and advantages of the invention will become apparent from the following disclosure in which one or more preferred embodiments of the invention are described in detail and illustrated in the accompanying drawings. It is contemplated that variations in procedures, structural features and arrangement of parts may appear to a person skilled in the art without departing from the scope of or sacrificing any of the advantages of the invention. 
     SUMMARY 
     To meet these objectives, the present invention features a cutting tool for workpiece cutting that comprises 1) a clamp that is sized to attach to the workpiece, 2) a rotating platform that is rotatably attached to the clamp, 3) a latch with a first latch member attached to the rotating platform and a second latch member latching to the first latch member. Prior to latching, the second latch member as assembled so have to have 1) a track attached to it with a carriage moveably attached to the track , 2) a positioning arm attached to the carriage, and 3) a cutting torch holder attached to the positioning arm. The latching mechanism minimizes weight and bulk during the initial workpiece clamping after which the rest of the cutting assembly cam be quickly latch to the clamped assembly with a minimum of further alignment and setup time. 
     The invention features a quick acting “Vise-Grip” type clamp to quickly and accurately clamp the cutting tool to the workpiece. The clamp uses a four pivot pin mechanism with a stationary jaw attached to a moveable jaw with a first pivot pin, a connecting handle attached to the stationary jaw with second pivot pin, a moveable handle attached to the connecting handle by a third pivot pin and to the moveable jaw with a fourth pivot pin. This four pin arrangement allows for quick and accurate alignment of the clamp with the workpiece and affords a quick and sure locking clamp. 
     To adjust the clamp for different workpiece thickness, the clamp features a moveable locking rod that is attached to the moveable jaw of the clamp. The moveable locking rod is locked to the moveable jaw with two nuts. The rotating platform has a hole formed in it for receiving a fixed circular center post projecting upward from the clamp and serving as the center of rotation for the rotating platform. An arcuate slot is formed in the rotating platform for receiving a threaded shaft with an attached handle. The treaded shaft passes through the arcuate slot and into a threaded hole in the clamp and locks the rotating platform to the clamp when it is rotated into the threaded hole using the attached handle. The rotating platform also has a hole in it for receiving a thumb screw that is screwed into a threaded hole in the clamp in order to accurately and quickly set the rotating platform to an exact ninety degree crosscut position. 
     The track and carriage of the current invention has a track with a housing that has a lead screwed rotatably mounted in it. The lead screw is rotatably driven by a motor attached to it by means of a coupling clutch. The lead screw linearly drives a block with an attached slide. The track also has a U-shape cover attached to the housing to keep dirt and debris from entering into the housing. To achieve protection of the housing and its associated parts, its was necessary to devise a way in which to cover the housing while at the same time driving the moveable carriage with components that has been covered. To this end, a U-shaped carriage was designed and attached to the track slide. The carriage was designed in a U-shape having a U-shaped slot formed in it so that the U-shaped cover would fit into the U-shaped slot. In effect, the housing cover passes through the specially designed U-shaped carriage. 
     One of the features of the present invention is its application to align and set up the tool using its light weight base. It is too be appreciated that working with a small unit is a lot more convenient than working with a heavy and bulky machine especially on rickety scaffolding under dark and inhospitable conditions. The slam latch makes its possible. It essentially divides the tool into two parts with initial alignment of the entire machine done on the basis of its much smaller clamping portion. Once the base is clamped down, the remainder of the machine can be easily locked into place using the slam latch. 
     The first part of the latch, i.e., the part associated with the clamp comprises latch member with 1) a hock with an outward facing groove, aid 2) a latch with an outward facing notch. The second latch member comprises 1) a first aperture that receives the hook, and 2) a second aperture that receives the latch, i.e., the hook and latch project into holes in the second member when the second member is latched into place. The first aperture has a pin (rod) passing through it with its ends secured in the latch member. In operation this pin is placed in the groove formed in the hook. The pin and groove combination serves as an axis of rotation as the other end of the second member is rotated down on the latch. The second aperture has a retractable plunger pin projecting into it and secured to the second latch member. The engagement of the plunger pin with the notch in the latch effectively locks (latches) the two latch members together. 
     Although the slam latch can be securely attached to the track with bolts or other fasteners, this severely limits the operational range of the cutting tool. As such, it was important to devise a simple way to reposition the upper latch member to the track. To this end, a slot was formed in the base of the track. Although only one slot need be used, the second, spaced-apart slot adds strength and rigidity to the entire assembly. A groove was also formed in the upper latch member that aligned itself with the slot formed in the base of the track. A circular passage was formed in the upper latch member at right angles to the groove. A lock plate was constructed with a flange formed at its upper edge at right angles to the body of the lock plate as well as having an aperture formed in it. The lower portion of the lock plate which is opposite the flange, extends through the slot formed in the base of the track until the flange contacts the upper surface of the base of the track. The base of the plate also extends into the groove in the latch member. The plate is moveable lengthwise along the slot. A cam lock is formed as a cylinder with a cam lobe projecting outward from the cylindrical shape of the cam lock. The cam lock is rotatably secured in the passage formed in second latch member. The cam lock is rotatably secured in the passage formed in the upper latch member and passes through the aperture formed in the lock plate. The flange of the lock plate draws the base of the track downward to contact an upper surface of the upper latch member as the cam lobe rotates downward in the aperture formed in the lock plate and urges the lock plate downward to lock the base of the track to the upper surface of the latch member. 
     The next component of the invention is the positioning arm. Generally the purpose of the positioning arm is to position the torch away from the clamp and track and carriage during the cutting operation so as to avoid damage to these components from the heat and molten metal produced during the cutting process. The positioning arm is made up of a housing that is attached to the carriage. An arm moves into and out of the housing and has a slot formed in its side. A rack is mounted within the arm. The teeth of a pinion gear project through the slot of in the arm and engage the rack teeth. A shaft has the pinion gear attached at one end and a handwheel attached at the other. 
     When cutting bulb flats at an angle, a straight line cut will leave the lower end of the bulb flat projecting beyond a plane passing through the edge of the cut at the bulb surface. This tends to leave a large between the bulb flat at every position except where the lower edge of the bulbs project outward from the cut and touch each other. As such, it is desirable to move the torch laterally as well as along the direct of cut when cutting the bulb portion. In the past, the only way to achieve both a forward and a lateral cut was with a double drive device, i.e., a track moving the carriage in a first direction while a second carriage moves the torch laterally, typically by moving the first carriage. Thus it is one of the object of the present invention to achieve both forward and lateral movement of the cutting torch using only a single moving carriage. 
     This was accomplished by using developing a lateral torch position manipulator. Such a manipulator comprises a fixed block (non-moveable) unit attached to the carriage and a cam pattern block attached to the track. A movable block unit has the position arm attached to it and is moveably attached to the fixed block unit. The movable block unit has a cam follower arm with a cam wheel that contacts the cam pattern block. As a result, the movable block unit moves laterally with respect to the fixed block unit in response to the cam wheel following the cam pattern block. 
     The fixed block unit has a housing; attached to the carriage with stationary end blocks attached to the fixed housing and a stationary spring block also attached to the housing. A rod is attached at one end to the stationary end block and at the other end to the spring block. The fixed block unit also contains a moveable block. The moveable block has a hole formed in it with the rod passing through the hole. Since this is the only restraint on the moveable block and the radius of the hole is larger than the radius of the rod, the moveable block is able to move along the rod between the end block and the spring block. A tension spring is connected at one end to the moveable block and at the other end to the spring block. As a result, the spring pulls the moveable block toward the spring block. Since the moveable block is connected to the moveable block unit by means of a plunger projecting into the moveable block. As a result, any force that tends to move the moveable block outward toward the end block will result in a counter force from the tension spring tending to bull the moveable block unit back toward the track. In effect this is the method by which the cam follower wheel is held against the track and cam block. 
     As shown in figure twenty, one of the limitations of the present invention is that it is not possible to make angle cuts when the work piece to be cut is attached to a wall. As is evident, rotation of the unit angles the cutting torch way from the wall and bring the positioning arm and corner of the track in contact with the wall on the side opposite to the cut. To this end, it has been found that the installation of a second rotating platform that rotatably attaches the positioning arm to the carriage will eliminate this problem. As seen in figure twenty, rotation of the positioning arm toward the wall on the cutting side will bring the torch to a position where it will be able to completely cut the workpiece without doing damage to the wall. 
     The second rotating platform comprises to plates, a base plate that is attached to the carriage and a rotating plate attached to the positioning arm with the rotating plate also being rotatably mounted to the base plate by means of a pivot pin. Similar to the first rotating platform, the second platform as an arcuate slot for receiving a handled bolt that is received in a threaded hole in the base plate. The rotating the bolt into the threaded hole, the rotating plate is locked to the base plate. The arcuate slot allows such locking to take place throughout the range of angles through which the positioning arm is turned within the range permitted by the arcuate slot. A spring loaded plunger mounted on the rotating plate engages a hole in the base plate. By placing this hole at zero angle of rotation, it is always easy to return the positioning arm to its non-angled position. Rotational indicia on the rotating platform and a base line on the base which serves as a reference indicator, permits exact angles to be maintained through the job. 
     Another feature of the present invention torch holder that allows the torch to be manipulated in three directions: angularly into and out of a plane along the cut line, angularly in the plane along the cut line, and linearly in the direction to which the torch is turned. Indicia with respect to both angular manipulations allow torch position to be exactly controlled. 
     The torch holder is composed of a base plate which is typically attached to the positioning arm and which has a circular recess cut into it. A rotating plate is mounted for rotation in the circular recess and affords rotational positioning of the torch in the plane of the cut. 
     T two spaced-apart torch clamp brackets are attached at one of each of their ends to the rotating plate with the other end attached to the torch and transfers the rotational motion of the rotating plate to the torch. The torch clamp is also able to pivot in and out of the cutting plane as a result of the fact that the torch clamp is mounted for pivoting on pivot pins mounted in the two spaced-apart torch clamp brackets at the ends opposite the ends of attachment to the rotating plate. A spur gear mounted in the torch clamp engages a rack mounted on the cutting torch to move it in and out of the torch clamp. 
     Rotation of the rotating plate mounted in the base plate is accomplished by means of a screw that passes through a cylinder moveably mounted in a slot in the rotating plate. As the screw is turned, the cylinder is urged against the wall of the slot causing the rotating plate to turn in that direction. Rotational indicia on the rotating plate align with a pointer in a viewing window in the base plate to give an exact indication of the amount of rotation to which the torch has been subjected and allows for the reproducibility of the cutting process. 
     As noted the torch rotates into and out of the cutting place as a result of the mounting of the torch holder on pivot pins at the ends of the torch clamp brackets. Pivoting about these pins is accomplished by means of a spur gear mounted in the torch clamp brackets which engages a curved rack mounted in the torch clamp. The torch clamp bracket has angle indicia along the path of the curved rack. A pointer formed in a window of the torch clamp bracket enables exact determination and reproducibility of the requisite angle. 
     In cutting processes involving structural members such as I- and T-beams, it is oven necessary to move the torch in a variety of directions and at considerable distance from the motor driven carriage. To accomplish such cuts, a second positioning arm may be attached to the first positioning arm, typically at right angles to the first positioning arm. Generally the housing of the second positioning arm is attached to the arm moving in and out of the housing. As with the first positioning arm, the second positioning arm has a housing, an arm moving in and out of the housing, a slot formed in the arm, and a rack inserted into the interior of the arm and accessible by pinion teeth of a pinion mounted in the housing on a shaft driven by a handwheel at its opposite end. 
     In addition to the extended reach afforded by a second positioning arm, it often is desirable to make cuts in both flanges of an I-beam or to make horizontal cuts in the web of an I- and T-beam, To this end a different type of clamp has been developed as well as a base plate that allows the motor driven carriage to be moved from a vertical to a horizontal position. 
     To this end, a clamp has been developed for rigidly clamping to both edges of the flange on a T- or I-beam and then having a pivoting plate mounted on the clamp to permit orientation of the motorized carriage in either a vertical or horizontal position. The clamp comprises a base plate formed from a horizontal plate and a vertical plate, a stationary clamping block fixed to the base plate, a moveable clamping block moveably attached to the base plate and urged to and from the first clamping block by means of a threaded rod rotating in a threaded hole formed in a block attached to the base plate. 
     For vertical and horizontal orientation of the motorized carriage, a pivot hole is formed in the base plate and a pivot plate is attached to the base plate by means of a pivot pin passing through the pivot hole and attached at each end to the pivot plate. The pivot plate moves between vertical and horizontal positions as a result of rotation about the pivot pin. 
     The pivot plate can be locked in the horizontal position and in the vertical position by means of a first handled pin that engages a hole in the horizontal plate of the base plate to lock the rotating plate to the horizontal plate and by means of a second handled pin engaging a hole in the vertical plate of the base plate to lock the rotating plate to said vertical plate in a vertical position. 
     Finally it is noted that torch cutting is a difficult art with even the light and adjustment of the proper flow of fuel and oxygen a most difficult task and only correctly done after years of experience. Unfortunately the adjustment process must be done with virtually every cut and even the skilled tradesman, it takes its toll on cutting torch parts and valves. To this end, it has been found that a unique combination of quick acting on-off valves, pressure regulators, and flow control valves virtually eliminate the need for torch adjusting and consistently give high quality torch cuts. To accomplish such consistency a pressure gauge, a flow control valve, and a quick-acting on-off value are used to supply fuel to the torch. The torch valve itself may always be left completely open. Similarly the oxygen supply is first regulated with a pressure gage and then split into two flows, one for heating and one for cutting. The heating flow is next sent through a flow control valve and then to a quick-acting on-off valve. The cutting flow need only be sent through a quick-acting on-off value. Once the pressure and flow control valves have been set, not further adjustment of the fuel and oxygen supply lines need be made. The workman then need use only the three on-off valves (fuel, heating oxygen, and cutting oxygen) for all cutting 
     The foregoing and other objects, features and advantages of the invention will become apparent from the following disclosure in which one or more preferred embodiments of the invention are described in detail and illustrated in the accompanying drawings. It is contemplated that variations in procedures, structural features and arrangement of parts may appear to a person skilled in the art without departing from the scope of or sacrificing any of the advantages of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     One or more preferred embodiments of the cutting apparatus according to the invention are described by way of reference to the accompanying drawings, in which 
     FIG. 1 is a perspective view illustrating the cutting tool of the present invention. 
     FIG. 2 is a side elevation view of the cutting tool illustrated in FIG. 1 attached to a workpiece. 
     FIG. 3 is a perspective view of a portion of the clamp assembly shown in FIGS. 1 and 2 with a portion of the connecting handle removed. 
     FIG. 4 is a side elevation of the upper jaw member, rotating platform, and the base of the slam latch. 
     FIG. 5 is a top view of the upper jaw member, rotating platform and the base of the slam latch. 
     FIG. 6 is a schematic partial cross sectional view showing the cam follower and torch positioning and manipulator assemblies. The track and carriage assembly and cover are shown in cross sectional view. A portion of the clamp, slam latch, and both rotating tables are shown in block form. 
     FIG. 7 is a schematic partial cross-sectional view showing the track assembly, lead screw, block and slide. The motor, reduction gears, and over-torque clutch are shown in block form. 
     FIG. 8 is a schematic drawing illustrating a fuel and oxygen flow system for regulating oxygen and fuel to a cutting torch. A housing for the regulators, throttle valves, and quick acting valves is shown in cross-section. 
     FIG. 9 is a top view of the latch assembly of the slam latch. 
     FIG. 10 is a plan side view of the latch assembly shown in FIG.  9 . 
     FIG. 11 is a plan side view of the of the locking plate used with the latch assembly shown in FIG.  9 . 
     FIG. 12 is a plan end view of the locking plate shown in FIG.  11 . 
     FIG. 13 is a partial view of the bottom plate of the track assembly illustrating slots used with the locking plate of FIGS. 11 and 12 and which allow the latch assembly to be moved along the base of the track assembly and locked into place. 
     FIG. 14 is a cross-section of along  14 — 14  of FIG. 9 illustrating the use of a cam lock to lock the latch assembly to the base of the track assembly. 
     FIG. 15 is and end view of the cam lock illustrating the cam lobe and a hexagonal socket for rotating the cam lobe. 
     FIG. 16 is an end view of a positioning arm assembly for moving the cutting torch to or away from the track and carriage assembly in a direction that is generally transverse to the travel direction of the carriage. 
     FIG. 17 is a partial cross-sectional view of the rack and pinion assembly used for moving the torch to or away from the track and carriage assembly. 
     FIG. 18 is a partial front elevation view of a sliding block unit illustrating retraction of cam follower arm in the sliding block unit. 
     FIG. 19 is a partial perspective view of a stationary block unit and a sliding block unit illustrating a spring mechanism for maintaining the cam follower arm in contact with the cam follower block. 
     FIG. 20 is a schematic view of the present invention illustrating the inability to perform an angled cross-cut of a workpiece attached to a vertical wall using only a single rotating platform. 
     FIG. 21 is a top view of a second rotating platform illustrating rotation of a rotating plate with respect to a base plate using a pivot pin. 
     FIG. 22 is a front elevation view of the second rotating platform of FIG. 21 further illustrating angle indica, a plunger pin for locating a perpendicular orientation, and a locking handle for securing the rotating plate to the base plate. 
     FIG. 23 is a top view of a cutting torch holder illustrating rotation into and out of the plane of the base, rotation in a plane parallel to the plane of the base, and linear movement of a cutting torch. 
     FIG. 24 is a front elevation of the cutting torch holder of FIG.  23 . 
     FIG. 25 is a side elevation of the cutting torch holder of FIG.  23 . 
     FIG. 26 is a perspective view of the cutting torch holder of FIG.  23 . 
     FIG. 27 is a front elevation of the rotation plate of the cutting torch holder of FIG. 23 illustrating plate rotation using a screw, slot, and push cylinder configuration. 
     FIG. 28 is a side elevation view of the rotation plate of FIG.  27 . 
     FIG. 29 is a side elevation view of the torch clamp of the cutting torch holder of FIG.  23 . 
     FIG. 30 is a clamp for attachment to T- and I-beam workpieces that allows for both horizontal and vertical positioning of the track and carriage assembly. 
     FIG. 31 is a cross-section along  31 — 31  of FIG. 30 illustrating the dovetail track of a moving clamping block. 
     FIG. 32 is a partial schematic drawing illustrating the pivot plate clamping details. 
     FIG. 33 is a partial schematic drawing illustrating the use of two cutting torch positioning assemblies. 
    
    
     In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology is resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is to be understood that each specific term includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. 
     Although a preferred embodiment of the invention has been herein described, it is understood that various changes and modifications in the illustrated and described structure can be affected without departure from the basic principles that underlie the invention. Changes and modifications of this type are therefore deemed to be circumscribed by the spirit and scope of the invention, except as the same may be necessarily modified by the appended claims or reasonable equivalents thereof. 
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in FIGS. 1 and 2, the torch cutting tool of the present invention, generally designated by the numeral  10 , comprises six subassemblies that provide for accurate torch cutting of supporting and stiffening workpiece such as bulb-flat stiffeners  14  (FIG.  2 ), I-beams, T-beams, and so forth used in the shipbuilding and other constriction arts. Specifically, these subassemblies are: 1) a clamping assembly, e.g., clamp  40 , for securing the device to the workpiece, 2) a rotating assembly, e.g., rotating platform  50 , that is rotatably attached to the clamp  40  and provides for making angled cuts of the workpiece, 3) a motorized track and carriage assembly  60  with a track  68  and linearly moveable carriage  66 , 4) a latch assembly  30  with a first latch member  160  attached to rotating platform  50  and a second latch member  180  attached to the motorized track and carriage assembly  60  for rapid attachment and detachment of the motorized track and carriage assembly  60  to the clamping assembly  40 , 5) a positioning arm  140  that allows for positioning of a cutting torch with respect to the workpiece away from the clamping assembly  40  and the carriage assembly  60 , and 6) a torch manipulator assembly  190  that allows for precise positioning of the cutting torch with respect to the workpiece. Positioning Clamp Assembly  40   
     Referring to FIGS. 1-3, the self-aligning clamp unit  40  is based on conventional, commercially available, ViseGrip type assemblies such as described in U.S. Pat. No. 2,592,807, all of which is included by reference as if completely written herein. As seen in FIG. 2, the clamp  40  comprises a stationary jaw  42  which is comprised of an upper jaw member  45  to which is rigidly attached side block  43  at its top. Two spaced-apart members  48 ,  48 ′ (FIG. 3) are rigidly attached to the bottom of side block  43 . Securing feet  46  are attached to the underside of upperjaw member  45  and the side of side block  43  for the purpose of engaging workpiece  14 . 
     A moveable jaw  213  is comprised of arm  210  to which is attached a first end of extension arm  41 . The opposite end of extension arm  41  terminates in a cylindrical portion  211  having an aperture  214  (FIG. 1) bored therein for receiving a threaded rod  49  which is secured to the cylindrical portion  211  by means of nuts  47 ,  47 ′. Threaded rod  49  terminates in securing foot  46  which engages workpiece  14 . The space between upper jaw member  45  and the end of rod  49  can be adjusted by selected location of nut  47  on threaded rod  49  so as to engage one end of cylindrical portion  211  followed by tightening of nut  47 ′ to engage the opposite end of cylindrical portion  211  thereby securing rod  49  to arm  41  with the requisite space between the upper end of rod  49  and the bottom of upper jaw member  45 . The use of adjustable rod  49  has the advantage of allowing adjustment of the clamp assembly  40  to accommodate various thicknesses of workpiece  14 . 
     The moveable jaw  213  is moveably secured to stationary jaw by means of pivot pin  215 . Specifically, the end  216  of arm  210  opposite the end joined to extension arm  41  passes between spaced-apart members  48 ,  48 ′ (FIG.  3 ). Pivot pin  215  (FIG. 2) passes through apertures  217  in spaced-apart members  48 ,  48 ′ and through an aperture formed in end  216  of arm  210  to rotatably secure arm  210  of the moveable jaw  213  to the spaced-apart members  48 , 48 ′ of stationary jaw  42 . Arm  210  of moveable jaw  213  also passes between spaced-apart tangs  218  of moveable clamp handle  212  and is moveably joined to spaced-apart tangs  218  by means of pin  219  which passes through apertures in tangs  218  and an aperture in arm  210 . Connecting clamp handle  220  is bifurcated into two spaced-apart arms  221 ,  221 ′ which are joined at their distal ends to the spaced-apart members  48 , 48 ′ of stationary jaw  42  by means of pin  222 . Arm  210  of moveable jaw  213  and spaced-apart tangs  218  on handle  212  to which arm  210  is attached by pin  219  passes freely between the bifurcated arms  221 ,  221 ′ of handle  220 , i.e, neither arm  210  nor tangs  218  are attached to arms  221 , 221 ′. A portion  223  of moveable handle  212  below the line of bifurcation into tangs  218  is pivotally joined to the bifurcated arms  221 , 221 ′ by means of pivot pin  224 . 
     Upper jaw member  45  extends beyond side block  43  (to the right in FIGS. 1 and 2) and has a rectangular opening  225  (FIG. 5) formed therein to form a handle portion  44  for carrying clamp  40  and also for positioning clamp  40  on workpiece  14 . Typically two clamps  40  are mounted to side block  43  by means of machine screws that pass through holes  226  into threaded holes on the underside of side block  43 . When handle  212  is opened, i.e., pulled away from handle  220 , it rotates about pivot pin  224  and causes moveable arm  213  to rotate about pin  215  in a counter-clockwise manner causing the end of rod  49  (the end with securing foot  46 ) to retract from workpiece  14 . When handle  212  is closed against handle  220 , it pivots about pin  224  causing arm  210  to rotate clockwise and bring the end of rod  49  into contact with workpiece  40 . 
     In operation, the device operator moves clamp handles  212  outward to move rod  49  in a downward position to provide sufficient clearance between the end of rod  49  and the upper jaw  45  so as to clear the bulb portion  17  of bulb-flat stiffener workpiece  14 . If necessary, rod  49  can be adjusted to provide the correct spacing with upper jaw  45  by repositioning nuts  47  and  47 ′. The device operator holds the clamp assembly  40  by means of handle  44  formed in upper jaw plate  45  and moves the device inward toward the bulb-flat stiffener workpiece until securing foot  46  on side block  43  engages the edge of workpiece  14 . Maintaining the clamp assembly  40  firmly against the edge of the workpiece  14 , each of the handles  212  of clamps  40  are closed to move rod  49  in locked position with upperjaw  45 . As will be apparent, locking of clamp  40  to the workpiece, properly aligns the remainder of the tool  10  for the cutting operation. 
     Rotating Platform  50   
     Referring to FIGS. 1,  2 ,  4  and  5 , a rotating platform  50  rotates with respect to upper jaw  45  about a fixed circular center post  52  that projects upward from upper jaw  45  into a center hole  59  formed in platform  50 . Alternatively the center post may project downward from the rotating platform  50  into a circular hole formed in upperjaw  45 . Two arcuate slots  54  are formed in rotating platform  50 . Handles  56  are attached to threaded posts  55  that pass through arcuate slots  54  and are then screwed into threaded holes  51  in upperjaw  45  and allow for the rotating platform  50  to be quickly and firmly secured in place when the desired rotational setting of platform  50  has been achieved. A thumb screw  58  is screwed into threaded hole  57  in upper jaw  45  to accurately and securely set rotating platform  50  for cross cutting (transverse, 90 degree cutting) of workpiece  14 . Alternatively, a spring loaded pin may be used that engages a hole in upperjaw  45  to set the rotational angle of platform  50 . The transverse orientation is used for cutting workpiece  14  at a right angle, an orientation typical when workpieces  14  are joined in a straight, end-to-end fashion. For shipbuilding purposes, bulb-flat stiffeners, (i.e., workpiece  14 ) are cut in a transverse direction for joining when midship sections of the ship are being assembled. Other angular orientations of rotating platform  50  are typically needed for joining workpieces  14  when ship sections at the bow and stern of a ship are assembled. 
     Track, Carriage, and Cover Assembly  60   
     The track, carriage, and cover assembly  60  with associated motor  62  and gear drive  65  is illustrated in FIGS.  1 , 2 ,  6  and  7 . The basic track  68  and associated slide  61  are shown in semi-schematic fashion in FIG.  7 . The track  68  is a common commercial product such as manufactured by Tol-O-Matic, Inc. Of Hamel, Minn. and is typically formed as a hollow elongate beam that has a generally square shaped cross section. Typically slide  61  is attached to a block  502  which is driven by a lead screw  64 . Lead screw  64  is journaled for rotation into track ends  506  and  508  and coupled to a motor  62  by means of a reducing gear assembly  65 . Additional details as to track assemblies can be found in U.S. Pat. No. 3,450,398 all of which is incorporated here as if completely written herein. A clutch coupling  504  such as made by R&amp;W America, LP is used to prevent damage to motor  62  and/or screw  64  in the event block  502  (and associated attachments, e.g., carriage  66 , torch, etc.) is driven to its limits or otherwise encounters an obstruction that causes an over-torque condition. Preferably clutch coupling  504  is a self-resetting type that resets when the over-torque condition is eliminated. 
     As shown in FIGS. 1,  2  and  7 , track  68  and slide  61  are protected by a cover  69  to prevent damage from molten metal and other debris encountered during the cutting operation. Carriage  66  is attached to slide  61  and travels along cover  69  by means of an inverted U-shaped channel  63  that is formed in U-shaped carriage  66 . The U-shaped channel  63  is made by formed carriage  66  from two pieces  602 ,  604  that are fastened together such as with machine screws  606  (FIGS.  2  and  6 ). 
     The motor  62  and reducing gear box  65  are standard commercial components. The motor is of permanent magnet DC brush-type construction such as produced by the Baldor Company. The gearbox is a 25:1 reduction gearbox. Motor  62  and gearbox  65  are connected using standard flexible couplings. As shown in FIGS. 1,  2 , and  7 , motor  62 , gearbox  65  and clutch  504  are protected by an aluminum cover housing  102 . Various auxiliary equipment such as quick opening fuel and oxygen valves  104 ,  106 , and  108 , input connectors  103  and  105 , and output connectors  111 ,  113 , and  115  are attached to housing  102  by means of mounting blocks  516 . Input connectors  103  and  105  are connected to fuel and oxygen sources via appropriate hoses (not shown). Similarly the output connectors  111 ,  113 , and  115  are connected via hoses to torch  90  via torch input connectors  518 ,  520 , and  522  (FIG. 6) to provide the requisite fuel and oxygen for the heating and cutting operation. 
     In the past, each torch cut required the adjustment of the torch flame via visual inspection of the flame using torch valves  162  and  164 . Unfortunately although a flame might look good, the flow and ratio of fuel and oxygen often are improperly set resulting in a poor cutting job. To avoid this problem and the constant need to adjust flow and fuel and oxygen ratios with each cut, two throttle control valves  116  and  118  are used to set the proper flow and ratio of fuel and oxygen. Use of control valves  116  and  118  (FIGS. 1 and 2) virtually eliminates all adjustment of fuel and oxygen supply (and associated wear and tear on the torch control valves  162  and  164 ) and insures the proper ratio of gas and oxygen to do a good cutting job with each and every cut. In operation, the torch valves  162 ,  164  (FIG. 6) are completely opened. Quick acting valves  104  and  106  are also opened and the correct flame obtained using throttle valves  116  and  118 . Thereafter, the flame need not be readjusted. All that need be done is to open quick acting valves  104  and  106 , light the torch, and commence the heating and cutting operation. A handle  117  is attached to housing  102  to facilitate carrying and mounting to the clamp assembly  40 . 
     A fuel and oxygen supply unit  110  is shown schematically in FIG.  8 . As shown, fuel is input via line  442  with pressure controlled by pressure regulator  444  after which it is sent via line  446  to throttling valve  448  and then to quick acting valve  452  from which it is sent to torch  450  via line  454 . Oxygen is input via line  420  with pressure controlled by means of pressure regulator  422 . After leaving regulator  422 , the output  424  is divided into two flow paths,  426  and  428 . The flow in line  426  is sent to metering valve  430  and then to quick acting valve  432  from which it is sent to torch  450  via line  434 . Oxygen in line  428  (cutting oxygen) is sent directly to quick acting valve  436  and then to the cutting torch  450  via line  438 . For consistency of the pre-heat flame among a variety of torches, it has been found preferable to control the flow of fuel and oxygen only to the pre-heat gas-oxygen mixture. 
     As shown in FIG. 8, the pressure control gauges  442 ,  444 , the throttle values  430 ,  448 , and quick acting valves  434 ,  438 , and  454  may be mounted in protective box-shaped housing  524  with handle  117  and recessed ends  526 ,  528  that protect hose connections from damage. However, it has been found that it is preferable to mount the throttle valves  116 ,  118 , quick acting valves  104 ,  106 ,  108 , and input and output connectors  103 ,  105  and  111 ,  113 ,  115 , respectively, on the motor housing  102  as shown in FIGS. 1 and 2 for ease of hookup, lack of possible hose entanglement with the cutting equipment and ready access to fuel and oxygen control functions. Pressure regulators  422 ,  444  continue to be placed in housing unit  524  to prevent damage and accidental change of the regulators. Finally it is to be noted that the motor  62  is connected to a source of electric power and suitable switches are provided for operator control of the motor starting, stopping, and reversing functions. 
     At the start of the work shift and with reference to FIGS. 1,  2 , and  6 , the cutting torch operator opens torch valves  162 ,  164  (FIG. 6) and the quick acting valves  104 ,  106  and  108  to their full open position and then sets the pressure valves  422 ,  444  (contained in regulator unit  110 ) according to the pressure of the oxygen and fuel supply pressures. He or she then sets the flow control (throttle) valves  116 ,  118  for the proper flow of fuel and oxygen. After the optimum flow is achieved, quick supply valves  104 ,  106 , and  108  are closed. From that point on, the torch flame is completely controlled by quick acting valves  104 ,  106  and  108 . For each cut, the operator opens the quick acting fuel valve  104  to its full open position, lights the torch, and opens the quick acting oxygen valve  106  to its fill open position. The torch is ready to preheat the work piece without further adjustment. After initial preheating, the cutting oxygen valve  108  is fully opened and the cutting operation carried out with out further adjustment of the torch. After the cut, quick acting vales  104 ,  106 , and  108  are closed. The heating and cutting process, using only quick acting valves  104 ,  106  and  108  is repeated for every cut without need for cutting flame adjustment. As should be readily apparent, traditional torch valves  162 ,  164  can be eliminated when using the present combination of fuel and oxygen controls and valves. 
     Slam Latch Connecting Device  30 . 
     As seen in FIG. 2, the slam latch device  30  comprises a base unit (a first latch member)  160  and a latch unit (second latch member)  180  and allows the motorized track and carriage assembly  60  to be rapidly and securely attached to clamp assembly  40  (via rotating platform  50 ) after the clamp assembly  40  has been positioned and secured to the workpiece  14 . As seen in FIGS. 4 and 5, the base unit  160  comprises an oblong plate  242  with a hook  34  mounted toward one end and a latch  35  mounted toward the other end. The hook  34  has an outward facing rounded groove  31  for receiving pin  36  mounted in an opening  39  formed at one end of latch unit  180  (FIG. 9) Latch  35  has an outward facing rectangular notch  38  formed in it for receiving latch pin  32 . Latch  35  has an outward facing downward ramp surface  33  formed in its upper region for facilitating the latching of latch pin  32  in notch  38 . Base plate  242  is mounted to rotating platform  50  by means of recessed bolt that are screwed into threaded bolt holes in rotating platform  50 . However, it is to be realized that other forms of attachment may be used. 
     As seen in FIGS. 9 and 10, latch unit  180  comprises an oblong block  246  with two oblong rectangular apertures  39  and  248  formed at opposite ends and which are of sufficient size to accept hook  34  and latch  35  in their entirety. A force fit pin  36  is received in hole  250  formed in block  246  and passes through rectangular aperture  39 . A hand-retractable spring loaded plunger  256  (Carr Lane Manufacturing) is screwed into a treaded aperture at the end of oblong block  246  with the plunger pin  32  extending into rectangular aperture  248 . A handle  258  can be attached to plunger  256  to facilitate retraction of plunger pin  32  necessary to release the latch unit  180  (and its attached motorized track and carriage assembly  60 ) from the base unit  160 . An inclined surface  252  (FIG. 10) is formed in the end of oblong block  246  (the end containing pin  36 ) to facilitate engagement of pin  36  with hook  34 . 
     In operation, pin  36  in the rectangular opening  39  of latch unit  180  is engaged in the rounded groove  31  of hook  34  by raising the opposite end of latch unit  180  and pulling pin  36  into groove  31 . Such engagement is facilitated by inclined surface  252 . After pin  36  is engaged in groove  31 , the latch unit  180  is rotated downward about pin  36 . Near the end of such rotation, latch pin  32  engages ramp surface  33  and is forced into retraction until it clears the bottom of ramp surface  33  at which point the spring loaded pin is forced into engagement with notch  38  to firmly lock the motorized track and carriage assembly  60  (attached to latch unit  180 ) to the clamp assembly unit  40 . That is, the first latch member  160  (which is attached to rotating platform  50  which is in turn mounted on jaw member  45  of clamp  40 ) is secured to the second latch member  180  (which is attached to the track  68  or track and carriage assembly  60 ). 
     Latch unit  180  can be secured to track unit  68  by means of bolts that pass through the base  512  of track unit  68  and which are screwed into threaded holes on the top surface of block  246 . However, it has been found advantageous to use a moveable attachment means for securing the base  512  of track unit  68  to latch member  180 . Such moveable locking attachment has the advantage of almost doubling the linear reach of the torch parallel to the track unit  68 . The moveable locking attachment is illustrated further in FIGS. 9-15. Specifically two parallel grooves  927  are formed lengthwise in oblong block  246  to moveably receive the base of locking plate  922 . As seen in FIGS. 11 and 12, locking plate  922  has a flange  923  formed at its top and an aperture  925  formed in its side. 
     As seen in FIG. 13, two spaced-apart parallel slots  930  are formed along the length of the base  512  of track assembly  68 . The distance between slots  930  and their width are essentially the same as grooves  927  in plate  246 . The slots  930  are sufficiently wide to moveably accept the base portion of locking plate  922  but are narrower than the width of locking plate flange  923  as is apparent in FIG.  14 . 
     A passage  931  is formed through the side of block  246  at right angles to the parallel grooves  927 . As seen in FIG. 14, the lower portion of locking plate  922  is passed through slots  930  in base plate  512  and then into grooves  927  formed in block  246 . A cam lock  924  with cam lobe  928  is placed within passage  931  and passes through aperture  925  in locking plate  922 . When the cam lock  924  is rotated within passage  931  about its axis  937  using an allen wrench to engage hex socket  929 , the cam lobe  928  contracts the bottom of aperture  925  in plate  512  and forces the locking plate  512  downward in grooves  927  as the cam lobe  928  moves to its downward position. As the flange  923  is forced downward by cam lobe  928 , flange  923  securely locks plate  512  to the top of block  246  thereby immovably securing track  68  to latch member  180 . As the cam lobe  928  is rotated upward, locking plate  922  moves upward and releases base plate  512  from its locked position with the top of block  246 . In the unlocked (upward cam lobe position), track  68  can be moved easily and quickly to any position along the length of slots  930 . A set screw  932  screwed into a threaded bore  933  in the top of block  246  engages a radial circular groove  935  about cam lock  924 . The set screw  932  is used to adjust the position of the axis of cam lock  924  and prevents cam lock  924  from moving too far upward within passage  931  thereby preventing sufficient downward travel of locking plate  922  to lock base plate  512  to the top of block  246  with flange  923 . Axially aligning holes  239  and  238  may be bored in block  246  (FIG. 10) and latch  35  (FIG.  4 ), respectively. A locking pin  240  (FIGS. 4 and 10) may be passed through holes  238  and  239  and secured as a safely lock in the event plunger pin  32  should ever be accidentally disengaged. 
     Torch Position Arm Unit  140   
     As seen in FIGS. 1 and 6, in its simplest form, torch position arm unit  140  comprises an arm  94  with a torch manipulator (holder)  190  attached to one end with the other arm attached to carriage  66  transverse to the direction of carriage travel. The arm  94  serves to locate the torch to the side of and away from the track and carriage assembly in order to avoid damage from the heat and debris generated during the cutting operation. 
     Since it is often desirable to position the torch  90  (FIG. 6) at varying distances from the track and carriage assembly  60 , the torch position arm unit  140  is typically formed as the rack and pinion assembly shown in FIGS. 1,  2 ,  16 , and  17 . The torch position unit  140  comprises a housing  322  of essentially hollow square cross section. Torch holding arm  94  is also of hollow square-cross section with a slot  710  formed in one side and fits within the hollow interior of housing  322  and is moveable in and out of the ends of housing  322 . A gear rack  706  is rigidly affixed within the hollow interior of holding arm  94  with gear teeth  702  accessible through slot  710 . A pinion gear  705  is housed in an opening  712  formed in housing  322  and positioned so that its teeth  704  engage the teeth  702  or rack  706 . Pinion gear  705  is attached to shaft  708  which is journaled into housing  322  for rotation using hand wheel  72 . Rotation of handwheel  72  causes pinion gear  705  to rotate and move rack  706  and attached arm  94  in and out of housing  322  to locate the cutting torch at a selected distance away from the clamp and track and carriage assemblies,  40  and  60 , respectively. When the cutting torch  90  is located in its desired position using handwheel  72 , it is locked into place using locking wheel  324 . 
     Although housing  322  can be mounted directly to carriage  66 , it is often desirable to provide additional location manipulation capabilities to the cutting torch. As a result and as will be discussed in more detail below, a torch position control unit (cam follower assembly)  70  can be used to automatically control the transverse position of the cutting torch with respect to the carriage travel direction. In such an instance, the positioning arm assembly  140  may be mounted to a lateral torch position manipulator  70  (FIG.  2 ). Also in some cases as when making angled cuts of a workpiece  14  that is attached at a right angle to a structural panel  16 , rotation of track and carriage assembly may make it impossible to cut the workpiece in the region of the structural panel. To overcome this problem a second rotating platform  80  may be used in which case the positioning arm assembly may be attached directly to the rotating platform  80  or to the cam follower assembly  70  which in turn is attached to the second rotating platform  80 . 
     Lateral Torch Position Manipulator  70 . 
     Typically when cutting thick materials that are to be welded together, it is desirable to angle the cut away from the abutting edges at the top to form a “scoop” for holding filler material during the welding process. In a scoop formation, the abutting edges are closest together at the bottom. The scoop provides good visibility to the bottom of the material and allows the initial weld to close (join) the close abutting edges at the bottom of the scoop. Once the bottom portion of the edge is joined, molten filler material can be built up in the scoop with minimal loss of molten material. Unfortunately, when a straight cross-cut of a bulb flat stiffener  14  (FIG. 2) is made with an angled torch, the cut at the base of the bulb  17  projects beyond a vertical transverse plane passing through the line of the cut at the top of bulb-flat stiffener  14 . When two such transverse, angled cut stiffeners are brought together for joining, only the very bottom portion of the bulbs abut each other with a large gap existing between the flat area of stiffener  14 . Such a gap must be filled with filler material resulting in heavy losses of molten filler and large amounts of time consumed in filling and closing the gap between the flats. To avoid, this problem the cutting torch must be moved in a transverse direction, i.e., away from the plane of the cross cut, when the bulb portion  17  of the bulb flat stiffener  14  is cut. To remedy this problem during the automated cut of stiffener  14  using the motorized track and carriage assembly  60 , a special lateral torch manipulator  70  has been devised that allows for lateral retraction of the torch while cutting the bulb portion using only a motorized carriage operating in a single direction. 
     The lateral torch manipulator  70  is illustrated in FIGS. 1,  2 ,  6 ,  18  and  19 . The lateral torch manipulator  70  consists of a fixed block unit  71  that is secured to carriage  66  and a moveable (sliding) block unit  73  that moves parallel to the fixed block unit  71 , that is, fixed block unit  71  is mounted transverse to track  68  and fixed with respect to carriage  66  while sliding block unit  73  moves transversely to track  68  as shown by arrow  730  in FIG. 1. A cam follower arm  74  attached to the sliding block  73  and having associated cam wheel  76  follows track  68  and cam pattern block  79  attached to the bottom plate  512  (FIG. 7) of track  68 . The cam pattern block  79  moves the torch in a lateral direction with respect to the cutting direction produced by carriage  66  to produce the proper scoop pattern and proximity of the bottom edges of two cross-cut bulb-flat stiffeners  14 . 
     FIG. 18 is a partial view of the sliding block unit  73  with the front cover removed to illustrate cavity  270  which is formed in sliding block  73  to accept a portion of cam follower arm  74  when in a retracted position as shown on the right side of block unit  73  in FIG.  6 . For retraction purposes, cam follower arm  74  has a slot  272 . A pin  274  passing through slot  272  secures the cam follower arm  74  to the sliding block  73  and allows for cam follower arm  74  to be retracted in and extended from sliding block  73 . A spring loaded detent  276  secured in plate  732  of sliding block  73  and an indent  278  formed in cam follower arm  74  maintains the cam follower arm in the retracted position. A spring loaded plunger  280  mounted in the shoulder  470  of the cam follower arm  74  engages a hole  472  in bottom plate  734  of sliding block  73  to secure the cam follower arm  74  in use position. As cam wheel  76  follows track  68  and cam pattern block  79 , the offset sideways motion of the cam pattern block  79  is translated into sideways motion of the cutting torch  90  by means of the mechanism illustrated in FIG. 19, it being realized that torch  90  is mounted to arm  94  which is locked in position with locking wheel  324  and that the housing  322  of positioning arm assembly  140  is immovably secured to sliding block unit  73 . 
     Sliding blocks  284  of stationary block  71  are immovably attached to the cover plate  736  of sliding block unit  73  by means of spring loaded plungers  294 . When a cam follower arm  74  is placed in operation, block  284  on the side of the cam follower arm  74  is locked in position with respect to sliding block  73 . Block  284  on the opposite side is not secured to sliding block  73  and is drawn up to the end of block  286  by spring  78 . Block  286  is immovably secured within stationary block unit  71  as are end blocks  288 . Rods  290  are force fit into holes in blocks  286  and  288 . Blocks  284  have holes  292  formed in them that allow blocks  284  to slidably move along rods  290 . To maintain follower wheel  76  in contact with the track and cam pattern block  79 , spring  78  is secured to stationary block  286  and to moveable block  284 . Thus as the sliding block  73  to which block  284  is immovably attached moves transversely in response to cam pattern block  79 , spring  78  urges sliding block  73  in the opposite direction to maintain the cam wheel  76  in contact with track  68  and cam block  79 . Spring loaded plunger  296  allows the sliding block  73  to be locked into position with stationary block  71  when transporting the unit or when cam follower action is not desired. 
     Housing  322  for the positioning assembly  140  is immovably attached to sliding block  73 . The rack  706  is mounted within torch holding arm  94 . Typically when the cam follower assembly  70  is used to control the lateral position of torch  90 , the torch holding arm  94  is locked into immoveable position by means of locking wheel  324 . However, in certain instances when it is desirable or necessary to control lateral movement of torch  90  manually, the locking wheel  324  is used to release the torch holding arm  94  and the lateral torch position can be controlled manually by means of hand wheel  72  which retracts or extends arm  94  by means of the rack and pinion assembly. 
     To use the lateral torch position manipulator  70 , the cam follower arm  74  on the side opposite torch  90  is withdrawn from its holding cavity  270  in sliding block  73  and pivoted downward about pin  274  to bring the cam follower wheel  76  in position against track  68 . Arm  74  is secured in its down position as a result of plunger  280  engaging hole  472  in bottom plate  734 . The sliding block  73  is released from its locked position with stationary block  71  by releasing plunger  296 . Block  284  is positioned over a hole in cover plate  736  of sliding block unit  73  and locked into place with spring loaded plunger  294 . Cam follower wheel  76  is held in place against track  68  and cam pattern block  79  by means of the tension produced by spring  78 . As the cam follower wheel is driven over the cam pattern block  79  as a result of the movement of carriage  66 , it displaces the sliding block  73  in a lateral direction which in turn produces a similar lateral displacement at torch  90  to produce the proper scoop and abutting lower edge in bulb-flat stiffener  14 . 
     Second Rotating Platform  80   
     As seen in FIG. 20, when the first rotating platform  50  is rotated to make an angled cut b across the end of flat-bulb stiffener  14 , it is found that the torch  90  no longer reaches to wall  16 , i.e., to point c, to make the desired cut. As is apparent, rotation of platform  50  brings the end of positioning arm  94  in contact with wall  16  at point a. 
     In order for the torch  90  to reach the hull or bulkhead at point c to initiate the cut, a second rotating platform  80  is used (FIGS. 2,  6 ,  21  and  22 ). The second rotating platform  80  comprises a base plate  350  that is mounted to carriage  66  with suitable fasteners. A rotating plate  352  is moveably secured to the base plate  350  by means of pivot pin  354  (FIG.  21 ). An arcuate groove  356  accepts a handled bolt  358  that is received in a threaded hole  950  in base plate  350  and allows the rotating plate  352  to be secured at a desired angle by turning the handle of handled bolt  358 . A spring loaded plunger  360  allows the rotating plate  352  to be locked at zero degrees of rotation on entry of the plunger pin into a hole  952  in base plate  350 . Rotational indicia  362  on rotating plate  352  and a reference indicator such as line  364  on the base plate  350  allow for accurate and repeatable setting of the angle of rotation of rotational plate  352 . 
     Torch Holder  190   
     As shown in FIGS. 23-29, the present invention features a torch holder  190  for rapid, exact, and reproducible settings of the position of torch  90  (FIG.  6 ). Torch holder  190  is small, light weight and provides precise and accurate torch position adjustment in three axes. Torch  90  has a gear rack  951  (FIG. 6) attached to it that allows for z-axis adjustment by means of a spur gear  391  located in the spur gear cavity formed in spur gear housing  370 . The torch gear rack  951  is accommodated in key way  206  when torch  90  is positioned in torch clamp aperture  208 . Holes  376  in torch clamp  196  accept bolts  381  which tighten to hold torch  90  in place. Rotary disk  194  provides the appropriate work (bevel) angle for the cut. As seen in FIG. 26, rotary disk  194  is mounted in a circular recess  383  in base  378  and rotates about a pivot bolt  387  passing through an aperture in base mounting block  378  and aperture  382  in disk  194 . Indicia  386 , formed on the interior surface of circular rotary disk  194 , are visible through base plate window  384  and set by means of pointer  388 . A threaded hole  390  receives a handled locking bolt  393  that locks the rotating disk  194  at the desired angle. Arcuate slot  392  receives the locking bolt  393  and allows for rotation of the locking bolt  393  when adjusting the working angle of the torch. The rotating disk  194  is rotated by means of a screw adjuster  395  that passes through apertures formed in the sides of mounting block  378  and through threaded aperture  398  (FIG. 28) in push cylinder  396 . The axis of push cylinder  396  is placed transverse to the plane of the surface of rotary disk  194  (parallel to its rotational axis) in slot  408  and moves up and down in slot  408  as the rotational angle is changed using the screw adjuster  395  with adjuster knob  389 . 
     Torch clamp  196  pivots about a pivot bolt  230  in hole  201  allowing the travel angle to be adjusted as a result of the curved rack  198  mounted in rack housing  370  which is driven by pinion gear  200  which in turn is driven by pinion gear  202  which provides fine adjustment to the travel angle. Pinion gear  202  is mounted on shaft  204  which has an attached knob  207  for thumb-knob adjustment. Angle indicia  203  printed on the circular rack housing  370  can be accurately set using angle indicator  205  in viewing window  271  of clamp bracket  394 . Set screws  374  in clamp bracket  394  contact the circular rack housing to control the force necessary to reposition the travel angle. Arcuate slot  377  accepts the shaft  397  of spur gear  391  mounted in hole  192  and allows for adjustment of torch  90  by means of gear rack  951 . 
     A positioning arm clamp  960  is attached to base  378  by means of bolts  962 . The end  966  of a positioning arm is held in the clamp by means of bolt knob  964 . 
     Multipurpose Cutting System 
     It is to be realized that the clamping and cutting system detailed above was designed for bulb-flat cutting operations. In order to make the tool, more versatile, modifications have been made to the general configuration described above. 
     As seen in FIGS. 30-32, a clamp  750  is configured to comprise: 1) a base plate  751  formed from a horizontal plate  752  and a vertical plate  758 . A V-shaped clamping block  754  is affixed to the horizontal plate  752  and the vertical plate  758 . A second V-shaped clamping block  756  is formed with a dovetail  776  that slidably engages a dovetail groove  774  formed in horizontal plate  752 . The end of threaded rod  772  to rotatably attached to clamping block  756  and passes through a threaded hole in block  768  that is attached to horizontal plate  752 . A handle  770  is affixed to the other end of threaded rod  772  and on rotation causes clamping block  756  to move along dovetail slot  774 . As shown, V-blocks  754  and  756  are placed on opposite edges of flange  777  and handle  770  turned to bring blocks  754  and  756  in clamping engagement of flange  777 . 
     A pivot plate  780  is mounted to the base plate  751  by means of a pivot pin  782  that passes through hole  760  formed in horizontal plate  752  so as to be moveable from a horizontal position to a vertical position,. Handled pins  784 ,  785  lock the pivot plate  780  in either a horizontal or vertical position. In the horizontal position, handled pin  785  engages hole  762  to lock the pivot plate in a horizontal position. In the vertical position, handled pin  784  engages hole  764  in vertical plate  758  to lock the pivot plate  780  in a vertical position. It is to be realized that terms such as “horizontal” and “vertical” are used for descriptive purposes and are not limiting as the cutting system may be used in any orientation. 
     In operation, a torch mounted to the positioning assembly  140  will cut flange  777  as the motorized track and carriage moves the torch in a horizontal fashion, i.e., parallel to the horizontal movement of the carriage along its track. When the pivot plate  780  is moved to the vertical position, the carriage moves in an up and down (vertical) direction as it travels along its track. A torch mounted to the positioning assembly  140  would cut the web  779  of the workpiece I-beam  775  in a vertical direction. If the track assembly  60  is rotated ninety degrees when the pivot plate  780  is in the vertical position, the track is parallel to the web of the beam and a torch would cut the web in a horizontal direction (parallel to the beam rather than across it) as the carriage moves along its track. 
     To cut the lower flange  778 , the carriage must move transversely across the beam. However as configured in FIG. 32, a torch would not extend downward sufficiently to cut the lower flange. To this end, another positioning assembly  798 , similar to assembly  140  previously described, can be attached to torch holding arm  94  by attaching housing  790  to arm  94  as shown in FIG.  33 . Housing  790  contains the torch holding arm  792  and moves it in a vertical (up and down direction) by means of a rack  794  driven by a pinion attached to handwheel  796 . Although torch holder  190  can be attached directly to the end of the rack  794  by means of clamp  960  attached to the base  378  of torch holder  190 , it often is desirable to further extend the end of the torch holding arm  792 . As seen in FIG. 1, this can be accomplished by dovetail rails  970  and clamping bars  972 . Clamping bar  972  has a slit  975  and square opening  974  in one end that accepts the square configuration of rack  706 . The clamping bar is tightened onto rack  706  by means of a bolt in hole  976 . The opposite end of clamping bar has a slit dovetail groove  977  that accepts the dovetail of rail  970  and is held in place by means of a bolt in hole  979 . 
     It is therefore understood that although the present invention has been specifically disclosed with the preferred embodiment and examples, modifications to the design concerning sizing, shape, and selection of components for a particular cutting task will be apparent to those skilled in the art and such modifications and variations are considered to be equivalent to and within the scope of the disclosed invention and the appended claims. 
     Various changes in configurations to other than those shown can be used but that which is shown is preferred and typical. Without departing from the spirit of this invention, various means of fastening the components together may be used.