PATENT ABSTRACT
A duct reinforcing rod and fabrication apparatus for use with a conduit and a threaded element dimensioned to fit within the conduit includes a positioning device to position the conduit at an insertion position and an insertion device for inserting the threaded element a predetermined distance into the conduit. A deformation device is also employed to deform the conduit such that the deformation occurs at two locations on the conduit, the two locations being longitudinally spaced from one another along a length of the conduit.

PATENT DESCRIPTION
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 60/412,722, filed on Sep. 23, 2002, herein incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates in general to a duct reinforcement rod and fabrication apparatus, and deals more particularly with a duct reinforcement rod and fabrication apparatus which increases the structural stability of ductwork while reducing fabrication time and component expense. 
     BACKGROUND OF THE INVENTION 
     Ductwork is utilized to facilitate the heating, ventilation and cooling of various buildings, both residential and commercial. The ductwork typically comprises individual duct sections which are then coupled together to form a continuous, largely airtight duct for conveying a moving mass of air. 
     The duct sections are typically made from strong, yet relatively light, material such as sheet metal, or the like. It is an important design characteristic that the duct remain as lightweight as possible in order to minimize the size and weight of fasteners and other structural components required to support the ductwork, as well as maintaining materials and fabrication costs of the ductwork itself at reasonable costs. 
     Commonly utilized ductwork often have rectangular, circular or oval cross sections, and are frequently manufactured and supplied in pre-cut lengths or sections with transversely outwardly protruding interconnection flanges, provided at opposite longitudinal ends of the section, to facilitate interconnecting duct sections at a job site and thus form the finished air conveying ducts of desired lengths. 
     Whatever the size or shape of the ductwork, the relatively small thickness of the walls of the ductwork, as compared to its cross-sectional dimensions, results in the duct walls being rather flexible. Conventional ductwork may therefore experience large, possibly destructive and oftentimes loud structural deformations if static or dynamic air pressure differentials between the interior and the exterior of the ductwork exceeds a predetermined threshold value. For this reason, mechanical engineering standards, as well as most building codes, require that certain ductwork be reinforced against expansion and/or collapse. 
     One known reinforcement mechanism for ductworks is shown in  FIG. 1  and includes a threaded tie rod  2  oriented between opposite planar sides of a rectangular duct  4 . Fixed, inner washers  6  are disposed adjacent the interior side of the opposing duct walls  4 , while exterior washers  8  are disposed on the exterior of the duct walls  4  in matching relation to one another. As shown in  FIG. 1 , a threaded nut  10  is screwed down against each of the exterior washers  8  to secure the reinforcing tie rod in position. 
     There are several variations of the reinforcing mechanism shown in  FIG. 1  and these variations may also include rubber o-rings or other elastic sealing devices disposed between the washers and the duct walls. Moreover, it is also known to replace the fixed, inner washers  6  with threaded nuts or lock nuts which may then be tightened in association with the tightening of the exterior threaded nuts  10  to provide the necessary rigidity to the reinforcing mechanism. 
       FIG. 2  illustrates a cross-sectional view of another known reinforcing mechanism which is comprised of a metallic tube  10  and an insert  12 . After the insert  12  has been disposed within the tube  10 , the tube  10  is crimped so as to deform in a radially inward direction. The crimped section of the tube  10  becomes locked within an annular groove  14  which has been inscribed about the periphery of the insert  12 , thus locking the insert  12  within the tube  10 . A threaded bolt  14  extends from the insert  12  and would extend beyond the exterior of a duct wall to be secured thereto via a threaded nut, or the like. The insert  10  may also include an inner cavity to accommodate an unillustrated biasing member, such as a spring, wherein the spring would outwardly bias the bolt  16  for greater flexibility. The insert  12  may be made from a metallic material or from a plastic or polymer material. 
     While these known reinforcing mechanisms are successful to a degree, they suffer from several logistical problems. The threaded tie rod  2  shown in  FIG. 1  is expensive to produce and deploy in a duct of any length. Similarly, the insert  12  shown in  FIG. 2  is also prohibitively expensive. 
     With the forgoing problems and concerns in mind, it is the general object of the present invention to provide a duct reinforcing rod which overcomes the above-described drawbacks while maximizing effectiveness and flexibility in the assembling process. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a reinforcing rod for ducts. 
     It is another object of the present invention to provide a reinforcing rod for ducts which do not utilize expensive constituent elements. 
     It is another object of the present invention to provide a reinforcing rod for ducts which utilize commercially available components. 
     It is another object of the present invention to provide a reinforcing rod for ducts which utilizes a pair of crimps to secure a threaded bolt or nut against longitudinal movement therein. 
     It is another object of the present invention to provide a reinforcing rod for ducts which will significantly reduce the overall expense of outfitting ductwork with such reinforcing rods. 
     It is another object of the present invention to provide a reinforcing rod for ducts is both quick to manufacture, as well as being reliable in use. 
     It is another object of the present invention to provide a fabrication apparatus to fabricate the reinforcing rod. 
     These and other objectives of the present invention, and their preferred embodiments, shall become clear by consideration of the specification, claims and drawings taken as a whole. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates one known reinforcement mechanism for ductworks. 
         FIG. 2  is a cross-sectional view of another known reinforcement mechanism for ductworks. 
         FIG. 3  is a cross-sectional view of a duct reinforcing rod utilizing a bolt element, according to one embodiment of the present invention 
         FIG. 4  is a cross-sectional view of the duct reinforcing rod shown in  FIG. 3  after a crimping operation has been accomplished. 
         FIG. 5  is a cross-sectional view of the duct reinforcing rod utilizing a nut element after a crimping operation has been accomplished, according to another embodiment of the present invention. 
         FIG. 6  illustrates the reinforcing rod of  FIGS. 3 and 4  as it is employed in association with a duct wall, according to one embodiment of the present invention. 
         FIG. 7  illustrates the reinforcing rod of  FIG. 5  as it is employed in association with a duct wall, according to another embodiment of the present invention. 
         FIG. 8  illustrates a partial, cross-sectional side, planar view of a vertical fabrication apparatus, according to one embodiment of the present invention. 
         FIG. 9  illustrates a top, planar view of work surface of the vertical fabrication apparatus shown in  FIG. 8 . 
         FIG. 10  is a partial cross-sectional view of the tubing of the reinforcing rod after it has been loaded into the vertical fabrication apparatus shown in  FIG. 8 . 
         FIG. 11  is a partial cross-sectional view of the tubing of the reinforcing rod after it has been pushed down upon a bolt arrested in the vertical fabrication apparatus of  FIG. 8 . 
         FIG. 12  illustrates the closed position of a pair of matching crimper slide blocks shown in  FIG. 8 . 
         FIG. 13  illustrates a partial cross-sectional view of a horizontal fabrication apparatus, according to another embodiment of the present invention. 
         FIG. 14  illustrates a partial cross-sectional elevational view of a clamping station. 
         FIG. 15  illustrates partial cross-sectional elevational view of a crimping station. 
         FIG. 16  illustrates a side elevation of the horizontal fabrication apparatus of  FIG. 13 . 
         FIG. 17  illustrates a front elevation of the horizontal fabrication apparatus of  FIG. 13 . 
         FIG. 18  illustrates the two separate feeding tracks used to supply the insertion elements for the horizontal fabrication apparatus of  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 3  is a cross-sectional view of a duct reinforcing rod  100 , according to one embodiment of the present invention. As depicted in  FIG. 3 , the reinforcing rod  100  includes a metal tubing  102  and a standard bolt, or jam nut,  104 . As illustrated in  FIG. 3 , the tubing  102  and the bolt  104  are sized so that the head  106  of the bolt  104  enjoys a fight fitting relationship with the inner diameter of the tubing  102  when the tubing  102  is pressed over the head  106  in the general direction of arrow A, as will be described in more detail later. 
     The tubing  102  is envisioned to be a common, commercially available metallic conduit, such as is utilized in electrical wiring, however the present invention is not limited in this regard as the tubing  102  may alternatively be formed from any elongated, rigid tubing without departing from the broader aspects of the present invention. Likewise, the bolt  104  is envisioned to be a common, commercially available metallic bolt, which itself may be formed from zinc, stainless steel or the like without departing from the broader aspects of the present invention. The utilization of a standard, commercially available threaded nut, in place of the threaded bolt  104  shown in  FIGS. 3 and 4 , is also contemplated by the present invention and will be described in more detail later in conjunction with  FIG. 5 . 
     It is therefore an important aspect of the present invention that the reinforcing rod  100  is constructed utilizing common, commercially available ‘stock’ components. By utilizing such components, the present invention significantly reduces the overall cost of manufacturing the reinforcing rod  100 , as compared to prior art devices. Further, and as generally discussed previously, a typical duct system will employ a large number of periodically spaced reinforcing rods, therefore the aggregate savings realized by employing a reinforcing rod according to the present invention is oftentimes quite large. 
       FIG. 4  illustrates the reinforcing rod  100  after the tubing  102  has been pressed over the head  106  of the bolt  104 . As depicted in  FIG. 4 , the tubing  102  is pressed over the head  104  so as to extend beyond the head  104  a predetermined amount. Indeed, it will be readily appreciated that the length of the threaded section  108  of the bolt  104  which extends beyond the tubing  104  may be varied in accordance with the specific design characteristics of the ductwork and the relative length of the bolt  104  utilized. 
     The reinforcing rod  100  shown in  FIG. 4  is crimped in a radially inward direction so as to capture the head  104  therebetween. In contrast to prior art devices, the present invention employs both first and second crimps,  110  and  112  respectively, disposed above and below the head  106  to ensure against longitudinal movement of the bolt  104  within the tubing  102 . 
       FIG. 5  illustrates a reinforcing rod  150  utilizing a threaded nut  152  in place of the bolt  104  shown in  FIGS. 3 and 4 , according to another embodiment of the present invention. As depicted in  FIG. 5 , the tubing  102  is pressed over the nut  152  and the tubing  104  is then is crimped in a radially inward direction so as to capture the nut  152  therebetween. As discussed in conjunction with  FIGS. 3 and 4 , the present invention employs both first and second crimps,  110  and  112  respectively, disposed above and below the nut  152  to ensure against longitudinal movement of the nut  152  within the tubing  102 . 
     It is therefore another important aspect of the present invention that the reinforcing rod  100 / 150  need not employ an inscribed, annual groove, or the like, in order to securely fix the bolt  104  or, alternatively, the nut  152 , from longitudinal movement within the tubing  102 . 
       FIG. 6  illustrates the reinforcing rod  100  as it is employed in association with a duct wall  154 . As shown in  FIG. 6 , the reinforcing rod  100  is secured against the duct wall  154  via the application of a nut  156  having matching threads with the bolt  106  fixed within the tubing  102 . Alternatively,  FIG. 7  illustrates the reinforcing rod  150  as it is secured against the duct wall  154  via the application of a bolt  158  having matching threads with the nut  152  fixed within the tubing  102 . Although not illustrated, the present invention also contemplates the use of rubber o-rings, washers, or the like, in conjunction with matching, threaded companions to the bolt  104  or the nut  152  to secure the reinforcing rod  100 / 150  to the planar sides of a duct. As will be appreciated, the rubber o-rings, washers, or the like may be utilized adjacent to the duct wall  154  in order to substantially attenuate or eliminate vibration of the duct wall  154  during air movement through the ductwork. 
     Reference will now be made to  FIGS. 8-12  in order to more completely describe a fabrication apparatus of the reinforcing rod  100 , according to one embodiment of the present invention.  FIG. 8  illustrates a partial, cross-sectional side, planar view of a vertical fabrication apparatus  200 , according to one embodiment of the present invention. As shown in  FIG. 2 , the vertical fabrication apparatus  200  generally includes a housing  202 , a work surface  204  and a rack and pinion mechanism  206 . The rack and pinion mechanism  206  further includes a tube pushing cylinder  208  which, when selectively actuated, serves to move the rack  210  in a vertical direction, thereby causing the pinions  212  to rotate accordingly. The movement of the pinions  212  cause the tube  102  to be pushed down over the head  106  of the bolt  102 , as will be described in more detail later. 
     A planar top view of the work surface  204  is depicted in  FIG. 9  and illustrates an arresting depression  214  in which the bolt  104  is mounted to await the movement of the tubing  102  thereon. A matching pair of crimper slide blocks  216  are also shown in  FIG. 9  and are selectively slidable towards one another in order to accomplish the formation of the crimps  110  and  112 , shown in  FIG. 4 . 
     In operation, the tubing  102  is mounted within the rack and pinion mechanism  206 , as illustrated in  FIG. 10 . As further illustrated in  FIG. 10 , the bolt  104  is mounted in the arresting depression  214  directly under the loaded tubing  102 . A pair of matching tube pushers  218  are disposed on either side of the loaded tubing  102  and operate under the biasing of the pinions  212  as a result of the actuation of the tube pushing cylinder  208 . The tube pushers  218  are designed to force the tubing  102  in a downward, substantially vertical motion and over the head  106  of the bolt  104 .  FIG. 11  illustrates the position of the tube pushers  218  after the tubing  102  has been pushed over the head  106  of the bolt  104 . 
     Once the tubing has been pushed over the head  106  of the bolt  104 , the pair of crimper slide blocks  216  are actuated and are brought to bear upon the exterior surface of the tubing  102 , as illustrated in  FIG. 12 . As the crimper slide blocks  216  impinge upon the exterior surface of the tubing  102 , a pair of angled crimpers  220 , shown in  FIG. 9 , create the crimps  110  and  112  in the tubing  102 . Thus, the head  106  of the bolt  104  is securely fixed between the crimps  110  and  112 . At this juncture, the tube pushing cylinder  208  is selectively caused to reverse direction and the reinforcing rod  100  is lifted away from the work surface  204  to be subsequently removed. It will be readily appreciated that both ends of the tubing  102  will be deformed to fix a bolt in either end thereof. 
     The vertical fabrication apparatus  200  may be electrically, pneumatically or hydraulically operated, or a combination thereof. In the preferred embodiment of the present invention, the operation of the vertical fabrication apparatus  200  is pneumatically actuated. 
     While  FIGS. 8-12  discuss the vertical fabrication apparatus  200 , the present invention also contemplates orienting the operation of the fabrication apparatus in the horizontal plane. In this regard,  FIG. 13  illustrates a partial cross-sectional view of a horizontal fabrication apparatus  300 . 
     As shown in  FIG. 13 , the horizontal fabrication apparatus  300  includes a support base  302 , a clamping station  304 , a crimping station  306  and an insertion device  308 . The clamping station  304  and the crimping station  306  each extend across the planar work surface  310  of the horizontal fabrication apparatus  300 , substantially perpendicular to the insertion axis X of the horizontal fabrication apparatus  300 . 
     The support base  302  is preferably a block of metal having a plurality of half-cylindrical depressions,  312 ,  314  and  316 , formed on the upper side thereof. The depressions are sized to accommodate a conduit of differing diameters and is selectively translatable in the lateral direction, that is, in a direction substantially perpendicular to the insertion axis X, so as to selectively position one of the depressions opposite the tooling opening or aperture of the clamping station  304 . 
       FIGS. 14 and 15  illustrate partial cross-sectional elevational views of the clamping station  304  and the crimping station  306 , respectively. As shown in  FIG. 14 , the clamping station includes a pair of pneumatically actuated clamping arms  318  disposed about the tooling aperture  320 . It is the function of the clamping station  304  to securely hold the conduit  322  (seen in  FIG. 13 ) in position, thereby preventing axial or transverse movement of the conduit  322  during the insertion and crimping process, to be discussed in more detail later. 
     The arms  318  of the clamping station  304  define an inner, substantially circular opening which act as the tooling aperture  320 . As will be appreciated, the arms  318  may be interchanged so as to provide a tooling aperture of appropriate diameter to match the diameter of the particular conduit being utilized. Moreover, the shape of the inner, circular opening of the arms  318  are meant to arrest, as opposed to deform, the conduit  322 . 
     Aligned with the clamping station  304 , the crimping station  306  of  FIG. 15  includes a pair of pneumatically actuated crimping arms  324  disposed about the tooling aperture  320 . It is the function of the crimping station  306  to produce the crimps,  110  and  112 , that hold the bolt or nut within the conduit  322 , as discussed previously in conjunction with  FIGS. 4 and 5 . Indeed, in order to form both sets of crimps,  110  and  112 , in a single operation, the crimping station  306  is preferably provided with two pairs of crimping arms  324 , disposed one behind the other as viewed in  FIG. 15 . 
     The arms  324  of the crimping station  306  define inwardly protruding, lateral impact edges  326  which are co-axially aligned with the tooling aperture  320 . The inwardly protruding, lateral impact edges  326  serve to impact and deform the conduit  322 , thereby producing the crimps  110  and  112  when the arms  324  move towards one another. As will be appreciated, the arms  324  may be interchanged so as to accommodate the diameter of the particular conduit being utilized. Moreover, the arms  324  may also be interchanged, as necessary, to address wear of the inwardly protruding, lateral impact edges  326 . 
     As best seen in  FIGS. 14 and 15 , the clamping station  304  and the crimping station  306  each include matching pairs of stop adjustment bolts  321 . The stop adjustment bolts  321  are utilized so as to adjust the amount by which the clamping arms  318  and the crimping arms  324  travel towards one another, and may thereby adjust the fixing pressure of the clamping arms  318  and the impact pressure of the crimping arms  324 . 
     Taking  FIGS. 13-15  in combination, the conduit  322  is first situated within one of the depressions,  312 ,  314  and  316 , the appropriate one of which has previously been oriented co-axially with the tooling aperture  320 . The conduit  322  is then inserted through the tooling aperture  320  of both the clamping station  304  and the crimping station  306  until its distal end is properly located by a block  328 , seen in  FIG. 13 . The clamping station  304  is then actuated to cause the arms  318  to move against and fix the conduit  322  during the insertion of the bolt  108  or nut  152  into the conduit  322 , and the subsequent crimping action. 
     Returning to  FIG. 13 , the insertion device  308  includes a nut insertion punch  330  and a bolt insertion punch  332 . The nut insertion punch  330  and the bolt insertion punch  332  are selectively actuatable by a pneumatically operated solenoid  336 . The solenoid  336  is itself may be selectively translatable in a direction substantially perpendicular to the insertion axis X so as to selectively position the operable end of the solenoid  336  opposite either the nut insertion punch  330  or the bolt insertion punch  332 . In a preferred embodiment of the present invention, however, the solenoid  336  is maintained in a stationary position, while the nut insertion punch  330  and the bolt insertion punch  332  are selectively translatable for actuation by the solenoid  336 . 
     One a bolt  108  or nut  152  has been properly loaded in opposition to an impact end  340  of the nut insertion punch  330  or the bolt insertion punch  332 , as will be discussed in greater detail later, actuation of the horizontal fabrication apparatus  300  will selectively cause the solenoid  336  to push against the nut insertion punch  330 , or the bolt insertion punch  332 , and the integral biasing springs  334 , thereby urging the bolt  108  or nut  152  into the secured conduit  332  in the direction of insertion axis X. As will be appreciated, the solenoid  336  serves to urge the bolt  108 , or nut  152 , into the conduit  322  by an amount which properly positions the bolt  108 , or nut  152 , to accept crimping on either side thereof, as illustrated in  FIGS. 4 and 5 . 
     The horizontal fabrication apparatus  300  of the present invention also selectively provides for the automatic feeding of the requisite bolts  108 , or nuts  152 , via a gravity feed device  342 .  FIGS. 16 and 17  show side and frontal elevations of the horizontal fabrication apparatus  300 , respectively, as equipped with the gravity feed device  342 . As shown in  FIGS. 16 and 17 , the gravity feed device  342  includes an elevated hopper  344  having two compartments,  346  and  348 , for separately storing the bolts  108  and the nuts  152 . 
     As best seen in  FIG. 17 , the gravity feed device  342  preferably includes two separate feeding tracks,  350  and  352 , which hold a plurality of bolts  108  and nuts  152  therein.  FIG. 18  illustrates the two separate feeding tracks,  350  and  352 , as well as their respective tracks,  354  and  356 , and shows how the bolt  108  and the nuts  152  are selectively positioned for insertion by the nut insertion punch  330 , or the bolt insertion punch  332 . 
     It will be readily appreciated that after the conduit  322  has been secured by the clamping station  304 , and the bolt  108  or nut  152  has been inserted therein via the gravity feed device  342  and the solenoid  336 , the crimping station will imprint the crimps  110  and  112  to the conduit  322  to securely fix the bolt  108 , or nut  152 , within the conduit  322 . All tooling of the horizontal fabrication apparatus  300  will subsequently retract for easy removal of the conduit  322 , which may then be processed in a similar fashion on its opposing distal end, forming the finished reinforcing rod  100  of the present invention. 
     As will be appreciated by consideration of the embodiments illustrated in  FIGS. 1-18 , the present invention provides a reinforcing rod for ducts which utilize standardized components to form a rigid and economical stabilizer. Moreover, the formation of a pair of first and second crimps to securely fix a standard bolt there between, including an fabrication apparatus for accomplishing this crimping, provides a heretofore unknown securing configuration which is both quick to manufacture, as well as being reliable in use. By employing the vertical fabrication apparatus  200 , or the horizontal fabrication apparatus  300 , to form the reinforcing rod  100 , the present invention significantly reduces the time, labor and expense of preparing stabilization and reinforcing rods for use in commercial and residential ductwork. 
     While the invention has been described with reference to the preferred embodiments, it will be understood by those skilled in the art that various obvious changes may be made, and equivalents may be substituted for elements thereof, without departing from the essential scope of the present invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention includes all equivalent embodiments.