Patent Publication Number: US-6701608-B2

Title: Automated machinery for fabricating a wrought-iron fence

Description:
BACKGROUND OF THE INVENTION 
     This is a continuation of application Ser. No. 09/672,150, filed Sep. 25, 2000, now U.S. Pat. No. 6,499,207, which is a division of Ser. No. 09/133,113, filed Aug. 12, 1998, now U.S. Pat. No. 6,151,772 which is a continuation-in-part of application Ser. No. 08/975,986, filed Nov. 21, 1997, now U.S. Pat. No. 5,971,365. 
     The present invention relates to fence construction. More particularly, the invention relates to an automated process for fabricating wrought-iron fences. 
    
    
     SUMMARY OF THE INVENTION 
     In general, the present invention in a first aspect provides an automated method for fabricating components of a wrought-iron fence. The method comprises the steps of (a) providing a plurality of horizontal runners and a plurality of vertical pickets; (b) automatedly welding the vertical pickets to the horizontal runners to form a fence panel; (c) automatedly transferring the fence panel to a table run-out conveyor which includes a set of chains with a pickup block on each chain; (d) utilizing the table run-out conveyor to automatedly transfer the fence panel to a conveyor loading station which includes a hydraulic-driven unit with pickup hooks capable of conveying the fence panel; (e) utilizing the hydraulic-driven unit to automatedly transfer the fence panel to an overhead conveyor line; (f) utilizing the overhead conveyor line to automatedly transfer the fence panel to a fence section straightener; (g) utilizing the fence section straightener to automatedly straighten the fence panel; (h) utilizing the overhead conveyor line to automatedly transfer the straightened fence panel to a wash tank; (i) utilizing the wash tank to automatedly wash the fence panel; (j) utilizing the overhead conveyor line to automatedly transfer the washed fence panel to a drying station; (k) utilizing the drying station to automatedly air-dry the washed fence panel; (l) utilizing the overhead conveyor line to automatedly transfer the dried fence panel to a paint tank; and (m) utilizing the paint tank to automatedly paint the fence panel. 
     In a second aspect the invention provides automated machinery for fabricating components of a wrought-iron fence from a plurality of horizontal runners and vertical pickets. The machinery comprises: (a) automated programmable means for welding the vertical pickets to the horizontal runners to form a fence panel; (b) automated programmable means for straightening the fence panel; (c) automated programmable means for washing the fence panel; (d) automated programmable means for drying the fence panel; (e) automated programmable means for painting the fence panel; (f) automated programmable conveyor means for conveying the fence panel from the welding means to the fence-straightening means; (g) automated programmable conveyor means for conveying the fence panel from the fence-straightening means to the washing means; (h) automated programmable conveyor means for conveying the fence panel from the washing means to the drying means; and (i) automated programmable conveyor means for conveying the fence panel from the drying means to the painting means. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic representation of an automated welding machine made in accordance with the principles of the present invention. 
     FIG. 2 is a schematic representation of an automated table run-out conveyor and an automated conveyor load station, made in accordance with the principles of the present invention. 
     FIG. 3 is a schematic representation of an automated fence section straightener made in accordance with the principles of the present invention. 
     FIG. 4 is a schematic representation of an automated wash tank made in accordance with the principles of the present invention. 
     FIG. 5 is a schematic representation of automated machinery for drying a fence panel, made in accordance with the principles of the present invention. 
     FIG. 6 is a schematic representation of automated machinery for painting a fence panel, made in accordance with the principles of the present invention. 
     FIG. 7 is a schematic representation of an automated conveyor system made in accordance with the principles of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     More specificially, reference is made to FIG. 1, in which is shown an automated welding machine, made in accordance with the principles of the present invention, and generally designated by the numeral  2 . 
     The automated welding machine  2  comprises a programmable, movable carriage  4 ; programmable pneumatic means  14  for automatedly clamping horizontal runners  3  to vertical pickets  5  in a perpendicular configuration on the movable carriage  4 , by clamps  6  automatedly powered and operated by automated pneumatic means  14 ; a hydraulic cylinder  12 , for forward and reverse movement of the carriage  4 ; a plurality of programmable welding guns  8 , for welding the horizontal runners  3  to the vertical pickets  5 , to form a fence panel  7 ; and a programmable photocell switch  10   a  for a hydraulic feed-speed control valve  11 , indexing the movable carriage  4  to move at a slower speed during the welding operation, and at a faster speed for conveying the clamped horizontal runners  3  and vertical pickets  5  to and under the welding guns  8  for welding, and away from the welding guns  8  after the vertical pickets  5  have been welded to the horizontal runners  3 . 
     The horizontal runners  3  and the vertical pickets  5  are manually loaded onto the movable carriage  4  with panel fixture. An operator then starts the automated welding machine  2 , which pneumatically clamps the vertical pickets  5  to the horizontal runners  3 , and automatedly indexes the carriage  4  for the faster and slower speeds. 
     Reference is now made to FIG. 7, in which is shown an automated conveyor system, made in accordance with the principles of the present invention, and generally denoted by the numeral  70 . The automated conveyor system  70  comprises a plurality of hydraulic power units  18 ; an overhead cable  22 ; a pulley  24 ; a plurality of limit switches  10 ; a plurality of timers  64 ; a plurality of chain-and-sprocket units  16 ; and a plurality of hooks  26 . 
     Reference is again made to FIG.  1 . 
     After the operator pushes a start switch  9 , the carriage  4  will “rapid travel” to the first picket  5  to be welded. At this point the photocell switch  10   a  will switch the hydraulic feed-speed control valve  11  from “rapid travel” to “feed speed.” After the picket  5  has been welded to the runner  3 , the photocell switch  10   a  will then switch to “rapid travel” for the next picket  5  to be welded. 
     After the last picket  5  has been welded, the carriage  4  will “rapid travel” forward to the end of the stroke of the hydraulic cylinder  12 . An elevator  13  controlled by a limit switch  10  will then lift the welded fence panel  7  from the movable carriage  4 . When the elevator  13  is in “full up” position, the carriage  4  will return to the start position. At the same time the conveyor system  70  will move the fence panel  7  away from the welding machine  2 , using the overhead cable  22 , a pulley  24 , and hooks  26 . 
     The automated welding machine  2  further comprises a base  15  on which the movable carriage  4  is mounted. The base  15  has an inverted “V” rail  17  and a “flat” rail  19  to channel the carriage  4  for forward and reverse motion. The hydraulic cylinder  12  raises and lowers the elevator  13 . The carriage  4  has two “flat wheels” and two “V-groove wheels.” The hydraulic cylinder  12 , which preferably has a one-hundred-and-forty-four-inch stroke, is mounted on the carriage  4 , with its rod end anchored to the base  15 . The hydraulic power unit  18 , which is preferably a three-horsepower unit, is rigidly mounted to the base  15 . The output of the hydraulic power unit  18  is preferably about three and one-half gallons per minute at a pressure of approximately five hundred pounds per square inch gauge. An overhead gantry  21  is mounted on the base  15 . The gantry  21  has mounted thereon six wire welders  8  and a “T” bar rail  23 . On the bar rail  23  are mounted six welding-torch dove-tail slides, with torch holders and torches. Screw handles allow torch adjustment in and out as well as up and down. The torches are preferably set up at approximately a forty-five-degree angle. Flexible cables run from the welder units to torches approximately forty-eight inches long. Elevator  13  lift is accomplished by arms with a rocker movement and the hydraulic cylinder  12 . A second gantry is mounted on the base  15  forward of the welding torches. To the second gantry is mounted an adjustable air-powered hold-down guide and clamps, to navigate each horizontal runner  3  to its correct spacing and position. A guide of brass sidewalls with a roller hold-down applies pressure on the horizontal runner  3  to keep it tight on the picket  5  during welding. Small air cylinders apply the downward pressure to the front of the runner  3 , to hold the runner in position. The small air cylinders are activated when the carriage  4  moves forward from the start position. Along with the small air cylinder a set of air-cylinder clamps aid in applying downward pressure to the rear of the runner  3 . The air-cylinder clamps are activated by forward motion of the carriage  4  and by an air valve (not shown), and are retracted at the end of the welding cycle. 
     Reference is now made to FIG. 2, in which is shown an automated table runout conveyor  28  and an automated conveyor loading station  29 , made in accordance with the principles of the present invention, the combination being generally designated by the numeral  20 . 
     After the fence panel  7  has been moved down line of the welding machine  2  by the automated conveyor system  70  (FIG.  7 ), the automated conveyor loading station  29  picks up and hangs the fence panel  7  on the overhead cable  22 . 
     The automated table run-out conveyor  28  comprises a set of chains (not shown) with a pickup block (not shown) on each chain. The pickup blocks are mounted on a special link, which allows normal functioning of the chain while conveying the panel  7  via the attached pickup blocks. The conveyor  28  is started and stopped by two limit switches  10 . When the elevator  13  (FIG. 1) is in “full up” position—its highest point—a limit switch  10  activates the conveyor  28  to move the panel  7  from the welding machine  2  (FIG. 1) to the conveyor loading station  29 . 
     At the conveyor loading station  29 , the drive blocks drop away and the panel  7  stops moving. Thereafter a limit switch  10  activates and starts the conveyor loading station  29 . The pickup blocks move to the pickup position for another panel  7 , where they are stopped by a limit switch  10 . 
     The conveyor loading station  29  is an hydraulic-driven  12 ,  18  unit with pickup hooks  26  for transporting a fence panel  7  from the table run-out conveyor  28  to the overhead cable  22  shown in FIG.  7 . The pickup hooks  26  are controlled both vertically and horizontally. The conveyor loading station  29  is activated by a limit switch  10  off the table run-out conveyor  28  when the panel  7  is in position for pickup. The first movement is vertical. The pickup hooks  26  lift the fence panel  7  off the table run-out conveyor  28  to a height which clears the conveyor  28 . The same set of pickup hooks  26  then carry the panel  7  horizontally toward the overhead cable  22 . The pickup hooks  26  carry the panel  7  over a second set of staggered pickup hooks  26  attached to the overhead cable  22 , thereby fully extending the hooks  26 , activating a limit switch  10 , and moving the fence panel  7  downward in a second vertical movement. The result is the setting of the panel  7  on the overhead cable  22  in the second set of staggered hooks  26 , to drain the paint from the horizontal runners  3 . A one-way limit switch (not shown) then activates a horizontal and vertical retraction of the hooks  26  in a retracting glide slope, thereby returning the hooks  26  to their original start position. The pickup hooks  26  are now ready to transport another fence panel  7 . The conveyor loading station  29  includes a vertical roller slide  29   a  and a horizontal roller slide  29   b  for transporting the fence panels  7  via the pickup hooks  26 . 
     Reference is now made to FIG. 3, in which is shown an automated fence section straightener, made in accordance with the principles of the present invention, and generally designated by the numeral  30 . 
     The fence section straightener  30  comprises a press member  32 , a rigid backstop  34 , a pair of hydraulic cylinders  12  to force a fence panel  7  against the backstop  34 , and limit switches  10  which control the position of the press member  32 . 
     The fence panel  7 , which has been automatedly transferred via the cable  22  and the hooks  26  from the conveyor loading station  29  to the automated fence section straightener  30 , is disposed between the press member  32  and the backstop  34 . 
     When the fence panel  7  is “delivered” from the conveyor loading station  29  and disposed between the press member  32  and the backstop  34 , a limit switch  10  at the run-out table conveyor  28  (FIGS. 1 and 2) activates the hydraulic cylinders  18 , which automatedly and in unison urge the press member  32  and fence panel  7  toward and against the backstop  34 , thereby straightening the fence panel  7 ; and automatedly and in unison release the straightened fence panel  7 . The limit switch  10  which controls the pressing operation is the same limit switch used to start the conveyor-loading cycle. After the fence panel  7  has been pressed straight, a second limit switch (not shown) is automatedly activated to retract the press member  32  and thereby complete the press cycle. 
     The press member  32  has an adjustable press stroke to prevent overcorrection or overbending of the fence panel  7 . 
     Reference is now made to FIG. 4, in which is shown a programmable, self-contained, pressurized wash tank  40  which includes a plurality of rotatable wash arms  42  equipped with high-pressure spray nozzles  42   a . The rotatable wash arms  42  are turned via a chain-and-sprocket unit  16  by an electric motor  44 , and eject a pressurized spray  46  at and toward a fence panel  7 . The spray comprises a mixture of heated degreasing solution and water. 
     The washing station (not shown) is a metal enclosure with an opening at each end. The openings allow the overhead cable  22 , the hooks  26 , and the fence panels  7  to pass freely therethrough. 
     The spray nozzles  42   a  are usually set at a forty-five degree angle with respect to the fence panel  7 . This angle enables washing all sides and parts of the fence panel  7 . A pressure-washing pump (not shown) with a gas or electric heat source (not shown) controls the temperature of the wash mixture at approximately 190° F. 
     The fence panel  7  is transported to and disposed within the pressurized wash tank  40  by means of the overhead cable  22  and hooks  26 . Limit switches  10  stop movement of the cable  22  to position and dispose the fence panel  7  within the pressurized wash tank  40 . The same limit switches  10  restart movement of the cable  22  to convey the fence panel from the wash tank  40 . 
     Reference is now made to FIG. 5, in which is shown automated machinery  50  for drying a fence panel  7 . The automated drying machinery  50  comprises a pair of programmable air blowers  52  which force compressed air through pipe ducts  54  to air knives  54   a . The automated drying machinery  50  is disposed in a programmable drying station (not shown). 
     A fence panel  7  is transported from the washing station (not shown) and automated wash tank  40  (shown in FIG. 4) to the automated drying machinery  50  and programmable drying station (not shown), using pickup hooks  26  suspended from the overhead cable  22 . The fence panel  7  is automatedly passed between juxtaposed, parallel, spaced-apart pipe ducts  54  while air is blown therethrough. The air knives  54   a  at the distal ends of the ducts  54  increase the pressure of the air, in order to blow excess wash solution from the fence panel  7 . The blowers  52  are preferably centrifugal blowers. The air knives  54   a  are beneficially set at about a forty-five-degree angle with respect to the fence panel  7  for the most efficient drying of the fence panel  7 . The drying station works continuously as the fence panel  7  is conveyed therethrough. 
     Reference is now made to FIG. 6, in which is shown automated machinery  60  for painting a fence panel  7 . Hydraulic cylinders  12  automatedly lift a paint tank  62  vertically to submerge therein a stationary fence panel  7  suspended from hooks  26  supported by the overhead cable  22 . Programmable timers  64  and limit switches  10  allow a delay of the conveyor system  70  (FIG. 7) sufficient to paint the fence panel  7  and to drain excess paint back into the tank  62  after the tank  62  has been automatedly lowered and returned to its starting position. 
     The paint dip-tank station (not shown) is driven by a hydraulic power unit  18  with a pair of hydraulic cylinders  18  and a vertical slide (not shown). The dip-paint tank  62  is mounted on the vertical slide. 
     The start cycle for the dipping operation is activated by a relay (not shown) with a start switch (not shown) disposed at the site of the automated welding machine  2  (FIG.  1 ). A limit switch  10  mounted overhead ensures proper positioning of the panel  7 . Another limit switch  10  at the top of the cycle will return the tank  62  to its starting position. 
     The paint-dip station (not shown) includes a filtration unit  64  to filter out paint contaminants such as soil, metal shavings, etc. 
     Reference is again made to FIG.  7 . 
     The automated conveyor system  70  is a continuous cable-driven system installed on the outer perimeter of the floor-plan site (not shown). A hydraulic motor  18   a  in a hydraulic power unit  18  drives the overhead cable  22  at a variable speed using a gear-reduction unit (not shown). The cable  22  has one long and one short hook (not shown) to horizontally “stagger” a fence panel  7  being suspended therefrom. The conveyor system  70  transports the runners  3 , pickets  5 , and panels  7  (FIG. 1) through the entire fabrication process, then makes a loop to return the pickup hooks  26  to the vicinity of the automated welding machine  2 . 
     The conveyor system  70  and the cable  22  are not limited to straight, linear motion. The cable  22  is capable of turning a corner equal to one-hundred and eighty degrees. A take-up station (not shown) keeps the cable  22  taut. 
     The conveyor system  70  is operable in both manual and automatic modes. In the preferred automatic mode, a cycle is started by a start switch (not shown) proximate the automated welding machine  2  (FIG.  1 ), and is stopped by a limit switch  10  proximate the dip-paint tank  62  (FIG.  6 ). In the manual mode it can be started and stopped at any point in the cycle.