Abstract:
A method and apparatus for repairing overhead conveyor chain by removing a section of track, locating a mobile repair station under the exposed track, and effecting the needed repair on the chain by cycling the intact chain past the mobile repair station and repairing it as it passes. Repair embodiments include re-swaging and repair, replacement or rotation of chain links.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to the field of repairing overhead conveyor chains 
       BACKGROUND OF THE INVENTION 
       [0002]    Overhead conveyor chains are used in numerous manufacturing and processing industries. They comprise links joined by link pins, and include bearing wheels which ride on supporting tracks. They may extend for several hundred to several thousand feet. A typical cost of a new chain is $60 per foot. Accordingly, manufacturers and processors like to maintain the useful life of a chain as much as possible. 14 years is a typical chain life. 
         [0003]    One limiting factor on chain life is loosening of the swage connection of the bearing wheel axel to the inner race of the bearing wheel on either side of a chain link. This requires replacement of the affected wheels. Another limiting factor is wear on the link pins, which eventually have to be replaced. 
         [0004]    Chains suffering from link pin wear are often repaired by using a “come along” secured at its opposite ends to spaced portions on the conveyor chain. The “come along” is tightened against the take up force applied to the chain. This loosens the chain between the come along securing points, allowing the removal and replacement of worn parts. 
         [0005]    Where extensive repairs are required, the entire chain may be removed from its trac. Worn pins, wheels or other components are removed and replaced with new counterparts. The cost to remove and either repair or replace chain is significant, e.g. $10-$12 per foot. The process typically takes 24 hours, 12 hours to remove, and 12 hours or more to repair or replace with a new chain, and if repaired, 12 hours more to replace the repaired chain. In addition, 36 hours of production down time means 36 hours of lost profit. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention comprises a method and apparatus for repairing overhead conveyor chain by removing a section of track, locating a mobile repair station under the exposed chain, and effecting the needed repair on the chain by cycling the intact chain past the mobile repair station and repairing it as it passes. As a result of this invention, a chain can be repaired at about 20% of the cost of removing an old chain and replacing it with a new chain, and can be accomplished in about 1/3 of the time it takes to remove and replace an old chain. 
         [0007]    These and other aspects, advantages and features of the invention will be more fully understood and appreciated by reference to the written description of the preferred embodiments and appended drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is an elevation of a portion of a conveyor chain moving along its track, with a section of track removed and a repair station positioned underneath the unsupported section of chain; 
           [0009]      FIG. 2  is an enlarged perspective view of a small section of conveyor chain; 
           [0010]      FIG. 3  is an elevated perspective view of a repair station with a swaging unit positioned on the repair table; 
           [0011]      FIG. 4  is a plan view of the repair station of  FIG. 3 ; 
           [0012]      FIG. 5  is an enlarged side elevational view of the re-swaging unit; 
           [0013]      FIG. 6  is a cross sectional view taken along plane VI-VI of  FIG. 5 ; 
           [0014]      FIG. 7  is a cross sectional view taken along plane VII-VII of  FIG. 5 ; 
           [0015]      FIG. 8  is a cross sectional view taken along plane VIII-VIII on  FIG. 5 ; 
           [0016]      FIG. 9  is a cross sectional view taken along plane IX-IX of  FIG. 8 ; 
           [0017]      FIG. 10  is a perspective view of a link repair station; 
           [0018]      FIG. 11  is a top plan view of a portion of a link repair station with a conveyor chain passing through the repair station; 
           [0019]      FIG. 12  is a top plan view of a portion of the link repair station; and 
           [0020]      FIG. 13  is a perspective view of a chain clamp of the link repair station. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    In the preferred embodiments, a section  10   a  of conveyor track  10  is removed, leaving a section of conveyor chain  20  exposed ( FIG. 1 ). A repair table  30  is placed under chain  20  where track section  10   a  has been removed. The chain is cycled passed repair table  30  and repaired, without having to remove the chain from track  10 . The “components list” (Table 1) sets forth the various components and their identifying numbers which will be described in further detail: 
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Components List 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Conveyor track 
                 10 
               
             
          
           
               
                   
                 Conveyor track section 
                 10a 
               
             
          
           
               
                   
                 Coveyor chain 
                 20 
               
             
          
           
               
                   
                 Center link 
                 21 
               
               
                   
                 Side links 
                 22 
               
               
                   
                 Link pins 
                 23 
               
               
                   
                 Link pin mounting extension 
                 24 
               
               
                   
                 Guide wheels 
                 25 
               
               
                   
                 Load wheels 
                 26 
               
             
          
           
               
                   
                 Axel 
                 26a 
               
               
                   
                 Inner race 
                 26b 
               
               
                   
                 Outer race 
                 26c 
               
               
                   
                 Bearings 
                 26d 
               
               
                   
                 Swaging detent 
                 26e 
               
             
          
           
               
                   
                 Mobile Repair Station 
                 30 
               
             
          
           
               
                   
                 Repair table 
                 31 
               
             
          
           
               
                   
                 Table work surface 
                 31a 
               
               
                   
                 Telescoping legs 
                 32 
               
               
                   
                 Roller 
                 33 
               
             
          
           
               
                   
                 Mobile supports 
                 34 
               
             
          
           
               
                   
                 Base 
                 34a 
               
               
                   
                 Wheels 
                 34b 
               
               
                   
                 Telescoping legs 
                 34c 
               
               
                   
                 Top platform 
                 34d 
               
               
                   
                 Locator blocks 
                 34e 
               
             
          
           
               
                   
                 Swage repair unit 
                 40 
               
             
          
           
               
                   
                 Slides 
                 41 
               
               
                   
                 Slide end blocks 
                 41a 
               
               
                   
                 Swage platform 
                 42 
               
               
                   
                 Mounting bracket 
                 43 
               
             
          
           
               
                   
                 Punch mounting band 
                 43a 
               
               
                   
                 Anvil mounting band 
                 43b 
               
             
          
           
               
                   
                 Chain track 
                 44 
               
               
                   
                 End plates 
                 45 
               
               
                   
                 Tie bars 
                 46 
               
               
                   
                 nuts 
                 47 
               
               
                   
                 Punch unit 
                 50 
               
             
          
           
               
                   
                 Punch cylinder 
                 51 
               
               
                   
                 Punch piston 
                 52 
               
               
                   
                 Punch insert 
                 53 
               
               
                   
                 Punch tip 
                 53a 
               
               
                   
                 Wheel capture sleeve 
                 54 
               
               
                   
                 End portion 
                 54a 
               
             
          
           
               
                   
                 Anvil unit 
                 60 
               
             
          
           
               
                   
                 Anvil plate 
                 61 
               
               
                   
                 Anvil insert 
                 61a 
               
               
                   
                 Anvil projection 
                 61b 
               
               
                   
                 Mounting plate 
                 62 
               
               
                   
                 Anvil base 
                 63 
               
               
                   
                 Push pins 
                 64 
               
               
                   
                 Push pin springs 
                 65 
               
             
          
           
               
                   
                 Pin repair unit 
                 70 
               
             
          
           
               
                   
                 Chain support channel 
                 71 
               
             
          
           
               
                   
                 Funneled end 
                 71a 
               
               
                   
                 Bottom slot 
                 72 
               
               
                   
                 Bottom opening 
                 73 
               
             
          
           
               
                   
                 Chain clamps 
                 75 
               
               
                   
                   
               
             
          
         
       
     
         [0022]    The tracks used in overhead conveyor systems have various configurations. Track  10  shown herein is of an I-beam configuration, with each section having a flange  11  which is bolted to the flange  11  of the next adjacent track section ( FIG. 1 ). Typically, the track sections are 5-10 feet in length. 
         [0023]    Conveyor chains come in various configurations as well. The particular conveyor chain illustrated in the present embodiments comprises a plurality of center links  21  joined to adjacent side links  22  by means of link pins  23  ( FIG. 2 ). The link pins  23  shown in these embodiments include upstanding mounts  24  for mounting other items, such as supporting platforms for conveyed articles. A wheel  26  is positioned on each side of a center link  21 , with an axle  26   a  passing through each of the load bearing wheels  26  and through center link  21 . In chain  20  shown in the present embodiments, a horizontally oriented guide wheel  25  is positioned between each pair of opposed side links  22 . 
         [0024]    Each load bearing wheel  26  comprises a center axle  26   a,  an inner race  26   b  carried on axle  26   a,  an outer race  26   c,  and a plurality of bearing rollers or balls  26   d  carried between the races. The outer rim of wheel  26  is mounted on outer race  26   c.  The inner races  26   b  are swaged to axle  26   a  by pressing the hub ends of the axle between a punch and an anvil. The punch creates a small indentation  26   e  on one hub end of axle  26   a,  as shown in  FIG. 2 . 
         [0025]    Over time, the swaged connection between axel  26   a  and inner race  26   b  can become loosened, creating wear between inner race  26   b  and axle  26   a,  and ultimately leading to disintegration of the wheel. Similarly as noted above, the link pins  23  become worn through engagement with the center links  21  and their adjacent side links  22 , and require replacement from time to time. The wear life of link pins  23  can be extended by using repositionable link pins as shown for example in U.S. Pat. No. 7,726,469. These pins can be “repaired” by rotating them between three different positions and three different wear surfaces, as each wear surface has become overly worn. 
         [0026]    Repair station  30  of the preferred embodiment comprises a repair table  31  having a work surface  31   a  mounted atop telescoping legs  32  ( FIG. 3 ). Legs  32  may optionally be provided with casters or wheels to enhance the mobility of the repair station. A supporting roller  33  is optionally positioned at one or each end of work surface  31 . A repair unit, such as swage repair unit  40  shown in  FIG. 3  or pin repair unit  70  as shown in  FIGS. 10-13 , is positioned on top of repair station work surface  31 . 
         [0027]    Repair station  30  may also comprise spaced mobile supports  34  ( FIG. 10 ), each comprising a base  34   a,  underlying wheels or casters  34   b,  upstanding telescoping legs  34   c,  a top platform  34   d  and locator blocks  34   e.  Such spaced mobile supports  34  can be used alone or in conjunction with repair table  31 . 
         [0028]    Swage repair unit  40  comprises a pair of spaced slides  41  mounted between end blocks  41   a  ( FIG. 3 ). A swage unit mounting platform  42  is slidably carried on slides  41  such that unit  40  can be repositioned along the length of the slides  41 . A sturdy upwardly opening “U” shaped mounting bracket  43  is mounted to platform  42 . One of the upturned legs of bracket  43  terminates in a sturdy circular mounting band  43   a,  which surrounds and firmly holds cylinder  51  of swage punch  50  in place. The opposite upturned leg of bracket  43  terminates in a semi-circular mounting band  43   b,  which embraces and supports swage anvil unit  60  ( FIGS. 3 and 4 ). A section of track support  44  having sloping end portions  44   a  ( FIGS. 5, 7, 8 and 9 ) extends from anvil unit  60  into the space between anvil unit  60  and punch unit  50 , for supporting chain  20  as it passes by. A depression  44   b  is formed in track  44  in the space adjacent punch unit  50  ( FIGS. 3, 8 and 9 ). This leaves the punch side wheel  26  unsupported and free for capture by the end portion  54   a  of capture sleeve  54  ( FIGS. 5, 8 and 9 ). 
         [0029]    To help reinforce and hold the punch unit  50  and anvil unit  60  from spreading when punch  50  is activated, end plates  45  are mounted on the upturned legs of bracket  43 , and are held against spreading movement by tie bars  46  passing through and between them, and secured in place by nuts  47  on either end of tie bars  46  ( FIGS. 4, 5 and 7 ). 
         [0030]    Swaging punch unit  50  comprises a punch cylinder  51  which contains a piston  52  having a punch insert  53  mounted in the end thereof ( FIGS. 5, 6, 8 and 9 ). Punch insert  53  includes a projecting tip  53  which actually does the swaging work of punch unit  50 . Punch unit  50  also includes a sliding wheel locating sleeve  54  which can be manually slid along the outside of punch cylinder  51  and into position with its end portion  54   a  capturing a load bearing wheel  26 , as shown in  FIG. 9 . 
         [0031]    Anvil unit  60  comprises a cylindrically shaped anvil base  63  ( FIGS. 5, 7, 8 and 9 ), which is mounted in, and is securely held in place, by the semi-circular anvil mounting band  43   b,  which comprises the upper end of one of the upstanding legs of mounting bracket  43 . This anchors anvil unit  60  in its place. 
         [0032]    A mounting plate  62  abuts and is secured to the face of anvil base  63 . Anvil plate  61  abuts and is secured to mounting plate  62  ( FIGS. 5, 7, 8 and 9 ). Mounting plate  62  extends down below anvil plate  61  and provides a mount for chain track  44  ( FIG. 5 ). Chain track  44  is mounted to and projects from the face of mounting plate  62 . It is also mounted to the bottom of anvil plate  61 , which it passes beneath. 
         [0033]    Anvil insert  61   a  is positioned in anvil plate  61  ( FIGS. 7, 8 and 9 ). Anvil insert  61   a  includes a circular projection  61   b  which actually engages the hub end of a wheel axel  26   a  during the re-swaging operation. Projection  6  lb projects slightly beyond the face of anvil insert  61   a  and anvil plate  61 , such that it projects into the slight recess in the center outside face of wheel  26 , where the hub end of wheel axel  26   a  is located. It also helps keep a small space between anvil plate  61  and wheel  26  during the re-swaging “punch,” minimizing the possibility of damage to wheel  26  ( FIG. 9 ). 
         [0034]    Spaced push pins  64  are slideably positioned in a bore which passes through anvil plate  61 , mounting plate  62 , and into anvil base  63  ( FIGS. 7, 8 AND 9 ). The bore is slightly large in diameter in mounting plate  62  and anvil base  63 , so as to accommodate the enlarged “hat” end of push pins  64 . Pins  64  are biased outwardly by springs  65  positioned behind them, such that they project out from the face of anvil plate  61 , and extend slightly into the space above chain track  64 . The enlarged hat ends on pins  64  keep them from being pushed out too far, or altogether. 
         [0035]    In operation, track section  10   a  is removed and repair station  30  with swaging unit  40  attached is positioned beneath the now exposed section of chain  20 . Repair station  40  is located such that chain  20  rests on chain support track  44  of swage repair unit  40 , between swaging punch  50  and swaging anvil  60  ( FIGS. 4, 8 and 9 ). A wheel  26  to be re-swaged is approximately located by moving chain  20 . Wheel  26  can be more precisely positioned in re-swaging position by sliding swage repair unit  40  back or forth along slides  41  ( FIGS. 3, 4 ). 
         [0036]    With a wheel  26  located directly between swaging punch  50  and swaging anvil  60 , wheel locating sleeve  54  is slid forward on cylinder  51  until its end portion  54   a  captures wheel  26  and holds it in place as shown in  FIG. 9 . The end portion  54   a  of sleeve  54  is cut away at  54   b,  such that it is easier for an operator to see that wheel  26  is properly located as sleeve  54  is slid forward over wheel  26 . The projecting anvil push pins  64  help keep wheels  26  and center link  21  properly aligned as one of the wheels  26  is captured by wheel capturing sleeve  54 . Once a link  21  and its opposed wheels  26  are thus located ( FIG. 8 ), punch piston  52  is driven forward so that punch tip  53   a  strikes hard against the hub end of axle  26   a.  This forces the opposite end of axle  26   a  hard against anvil projection  61   b,  and forces push pins  46  inwardly such that wheel  26  is hard against the end of anvil projection  61   b  ( FIG. 9 ). The projecting portions of said anvil and said punch which engage the opposite ends of an axel to be re-swaged, project far enough out from said punch and said anvil that the surrounding portions of said anvil and said punch do not compress the wheel being repaired except at said axel to be swaged. 
         [0037]    This re-swages axle  26  to the inner races  26   b  of wheels  26 . With the wheels  26  thus reswaged, piston  52  withdraws and push pins  64  push wheel  26  away from anvil projection  61   b . Chain  20  is then advanced until the next set of wheels  26  are located approximately between anvil unit  60  and punch unit  53 , and the operation afore described is repeated. 
         [0038]    The pin repair unit  70  comprises an elongated upwardly opening C-shaped channel  71 , through which chain  20  passes ( FIGS. 10-12 ). Repair station  70  can be used alone as shown in  FIG. 10 , or in conjunction with repair table  31 . Swaging unit  40  would be removed from table  31 , and chain channel  71  would rest on and pass over roller of rollers  33  on repair table  31 . 
         [0039]    Channel  71  includes an open slot  72  in its bottom wall, through which the heads of pins can pass as chain  20  passes through channel  71 . The slots  72  extend from each end and open into an enlarged opening  73  which facilitates greater access to the link pins  23  of chain  20 . The end portions  71  a of the sidewalls of channel  71  are flared outwardly to define a funneling end which helps feed chain  20  into and out of channel  71  as it passes. 
         [0040]    A pair of latches  75  are located generally at each end of the enlarged open area  73  in the bottom of channel  72 . A clamping plate  75   b  is pivotally mounted on a clamp mounting block  75   a,  which in turn is mounted to the sidewall of track channel  71 . When a chain  20  is moved into position for removing or rotating one or more link pins  23  positioned above opening  73 , clamps  75  are rotated from their opened position as shown in  FIG. 12  to their clamping position as shown in  FIG. 11 , where the generally V-shaped end  75   c  of clamping plate  75   b  engages a guide roller  25  of chain  20 . With chain  20  thus locked in place, link pins  23  which are positioned between chain clamps  75  can be removed without losing control of the rest of chain  20 . 
         [0041]    In use, chain  20  is advanced through channel  71  a portion at a time, with each portion covering the distance between clamps  75 . Chain  26  is clamped in place by closing clamps  75  as shown in  FIG. 11 . The link pins between clamps  75  are either rotated to new wear positions or removed and replaced with new pins. The chain is then advanced until another portion of chain  20  which has not yet been serviced is locked in position between clamps  75 . 
         [0042]    It will be understood that the forgoing is a description of preferred embodiments of the invention, and that various changes and alterations can be made without departing from the spirit of the invention.