Rod end coating apparatus
United States Patent 1 1 Mueller et al.  
 [451 Apr. 29, 1975 1 ROD END COATING APPARATUS [75] Inventors: Robert .1. Mueller. lnver Grove Heights. Minn.; Philip 0. .lesme. Jr.. Prescott. Wis.; John A. Calkins. Hastings. Minn.  
 [73] Assignee: Smead Manufacturing Company, Hastings. Minn.  
 [22] Filed: July 5. 1973 [21] Appl. No.: 376.701  
 3.696.780 10/1972 Fritzsche 118/312 Plillltll E.\&#39;aminerHenry S. .laudon Attorney. Agent. or I-irm-Dugger. Johnson &amp;  
 &#39;Westman [57] ABSTRACT Rod coating apparatus that includes a plurality of rod carrier assemblies mounted on a pair of endless chains to move therewith for removing one rod after another from a rod hopper assembly and convey the rods to move the rod end portions vertically downwardly through coating channels of a pair of fluidized bed coating assemblies which have slots for discharging powder under gravity flow into the path of movement of the rod end portions and troughs which the rod end portions move to aid in coating the then lower surfaces of the rods. Preheaters are provided for heating the rod end portions prior to the movement thereof into the coating channels to a temperature to melt the coating powder particles when the particles impinge thereon. and after the rods have been coated. post heaters to melt any particles adhering to the coating to provide a smooth coating. A blower cools the rods after the post heat. A stripper removes the coated rods from the rod carrier assemblies. A fluidized bed supply assembly is mounted beneath the fluidized bed coating assemblies for catching particles discharged by the last mentioned assemblies and have particles elevated therefrom to the coating assemblies.  
 19 Claims. 11 Drawing Figures ROD END COATING APPARATUS BACKGROUND OF THE INVENTION Apparatus for coating rod end portions. In the prior art it is old to provide a rod coating machine that has an endless conveyor that, as a rod is being conveyed. first the rod is swung in one direction to coat one end of the rod and thence in a second direction to coat the other end of the rod; however, such machines are very long and of a relatively complex construction. In order to overcome problems such as the above, as well as others, this invention has been made.  
 SUMMARY OF THE INVENTION Rod end portion coating apparatus that includes a plurality of spaced rod carrier assemblies mounted on an endless conveyor for removing one rod at a time from a rod hopper assembly and conveying the rods to move the end portions thereof through rod coating channels of fluidized bed assemblies that discharge coating particles by gravity flow into the channels to impinge on the heated rod end portions to coat the rod end portions, and heaters for heating the rod end portions prior to being moved through the channels to a sufficiently high temperature that the particles melt on the rod end portions when the rod end portions move through the channels.  
  One of the objects of this invention is to provide a new and novel fluidized bed rod end coating machcine. Another object of this invention is to provide new and novel fluidized bed assemblies having channels for the rod end portions to move through and discharge solid coating particles under gravity flow to contact the rod end portions. A further object of this invention is to provide new and novel fluidized bed apparatus for maintaining a nearly constant head of solid coating particles above the discharge slots through which the particles flow to contact the rod end portions that are to be coated. In furtherance of the last mentioned object, it is another object of this invention to provide new and novel fluidized bed assemblies having mechanism for removing particles from a fluidized supply of particles and discharge particles to fall into said supply.  
  An additional object of this invention is to provide new and novel cooperating rod hopper and rod carrier assemblies for removing one rod at a time from the hopper assembly and conveying the removed rod through a rod end portion coating step. In furtherance of the last mentioned object, it is another object of this invention to provide a rod carrier assembly for magnetically holding a rod as the rod end portions are carried through a rod coating step. A further object of this invention is to provide new and novel mechanism for carrying hanger file hanger rods through a rod end portion coating operation and discharging the coated rods in a predetermined orientation relative one another.  
  This invention find particularly advantageous use in coating the hanger rods of convention hanger file folders. In such folders, only the end portions of the rods are exposed. Coating the end portions with a material that is solid even at the high end of the normal room temperaturerange provides lubrication that facilitates the sliding of the rods on file cabinet hanger bars, covers burrs and etc. on the end portions of the rods, and improves the appearance. The power used is of a type that is conventionally used for coating rod end portions, for example, a Nylon powder; the manner of application and the machine for applying the powder described herein being new and novel.  
 DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross-sectional view of the apparatus of this invention, part schematically, that is generally taken along the line and in the direction of the arrows ll of FIG. 2, the central, rearend, and lower front corner portions being broken away;  
  FIG. 2 is a fragmentary transverse cross-sectional view generally taken along the line and in the direction of the arrows 22 of FIG. 1 to more clearly show the construction and mounting of a rod hopper assembly and a rod carrier assembly;  
  FIG. 3 is a fragmentary side view of one end portion of the rod carrier assembly that is generally taken along the line and in the direction of the arrows 33 of FIG. 4;  
  FIG. 4 is a plan view of an end portion of the rod carrier assembly that is generally taken along the line and in the direction of the arrows 44 of FIG. 3;  
  FIG. 5 is a fragmentary longitudinal cross-sectional view generally taken along the line and in the direction of the arrows 55 of FIG. 2 to more clearly show the construction of the lower end portion of the hopper assembly and show an end view of a rod carrier assembly;  
  FIG. 6 is a fragmentary rear view of the apparatus of this invention, said view being generally taken along the line and in the direction of the arrows 6-6 of FIG. 1;  
  FIG. 7 is a fragmentary, enlarged rear view of one of the rod coating fluidized bed assemblies, said view being generally taken along the line and in the direction of the arrows 77 of FIG. 1;  
  FIG. 8 is an enlarged, fragmentary plan view of one of the rod coating fluidized bed assemblies that is generally taken along the line and in the direction of the arrows 88 of FIG. I, the central portion being broken away;  
  FIG. 9 is an enlarged, fragmentary longitudinal view generally taken along the line and in the direction of the arrows 9-9 of FIg. 7 to further illustrate the construction of one of the rod coating fluidized bed assemblies;  
  FIG. 10 is a view of an end portion of one of the rods that is coated by the apparatus of this invention; and  
  FIG. 11 is a fragmentary, perspective view of the stripper and track mechanism.  
 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in particular to FIGS. I, 2, and 6, the apparatus of this invention includes a frame, generally designated 10 that has a pair of front corner uprights 11, a pair of rear corner uprights 12, a first longitudinally extending upper frame member 13 joined to the right hand uprights ll, 12, a second longitudinal frame member 13 joined to the left uprights l1, 12 a pair of transversely spaced, longitudinally extending lower frame members 14 joined to the uprights on the respective side, front and rear upper transverse frame members l7 and 15 respectively joined to the longitudinal frame members 13, front and rear lower transverse frame members (not shown) that extend between and are joined to the front and rear uprights respectively, and a pair of intermediate vertical frame members 19 that respectively extend between and are joined to the upper and lower longitudinal frame members. The frame members 19 are substantially more closely adjacent the uprights 12 than the uprights 11.  
  Mounted by the front end portions of the upper longitudinal frame members 13 is a transverse shaft 23, shaft 23 having a pair of transversely spaced sprockets 24 keyed thereto to rotate therewith. Adjacent the frame members 19, the frame members 13 rotatably mount a transverse shaft 25 while directly below shaft 25, frame members 19 rotatably mount a transverse shaft 27. On each of the shafts 25, 27, there is keyed a pair of transversely spaced sprockets 26 and 28 respectively. A first link chain 30 is extended around the right hand sprockets 24, 26, 28 while a second chain 30 is likewise extended around the left hand sprockets.  
  Referring now in particular to FIGS. 1, 2 and 6, the hopper assembly, generally designated 33, includes a pair of base supports 34 that are mounted in transverse spaced relationship on the shaft 23. The shaft is rotatably extended through the base supports 34 with the sprockets 24 being located between the base supports. Each base support mounts a mounting plate 35 to extend thereabove while each mounting plate in turn mounts a support plate 36 to extend thereabove. A transverse bolt 38 is extended through each support plate to be threaded into a side plate 39 that in turn in bolted to a block 40 to prevent the base supports pivoting on the shaft. Each block 40 is fixedly secured to the adjacent longitudinal frame member 13 to extend thereabove.  
  Each support plate also mounts a magazine support 37 to extend thereabove and inwardly toward the other support plate. To each support plate there is bolted a front plate 41, a vertical spacer bar 42 and a magazine plate 43 with the spacer bar longitudinally spacing the respective front plate from the magazine plate and the front plate located between the spacer bar and the iongitudinally adjacent magazine support 37. The magazine plate extends transversely to have its opposite vertical edges bolted to the magazine supports while the front plates extend inwardly toward one another but have the adjacent vertical edges thereof substantially transversely spaced from one another by a distance greater than the transverse spacing of the sprockets 24. The spacer bars space the front plates 41 from the magazine plate 43 a distance slightly greater than the width W of the hanger rod 45 (see rod 45 in FIG. 10). Transversely between the spacer bars 42, there are provided between each front plate 41 and the magazine plate transversely spaced, vertical spacer bars 46 and 47 respectively. Each of the bars 46 and 47 is bolted to the magazine plate and the respective front plate 41 to more rigidly secure the front plate and magazine plate together, and is of the same longitudinal dimension as bar 42. In the event that the apparatus of this invention is being utilized for legal size file folder rods, then the rod spacer bars 46 would be removed, the transverse spacing of bars 47 being greater than that of bars 46.  
  To each of the front plates, there is secured the right angle support bracket 50 that has a generally horizontal leg 50a extending rearwardly across the longitudinal spacing between plates 41, 43 and being spaced from the bottom edge of the magazine support plate 43 by a distance greater than the thickness of one of the rods. Further, a pair of rod clearance brackets 51 are secured to the magazine plate to extend downwardly therefrom. The lower surface of each of the brackets 51 is at an elevation that is above the top surfaces of the legs 500 by a distance that is greater than the thickness of one of the rods 45 but is substantially less than the thickness of two of the rods whereby only one rod at a time may be removed from the hopper in a manner to be described hereinafter (see FIG. 5).  
  In order to remove the rods one at a time from the hopper assembly and to carry the rods through other portions of the apparatus of the invention, there are provided a plurality of rod carrier assemblies, generally designated 57. For purposes of facilitating the description of the rod carrier assemblies, the particular rod carrier assembly being described will be the one that is mounted by the chains 30 and is located directly beneath the hopper magazine plate 43 and front plates 41 as shown in FIG. 5, it being understood that each of the rod carrier assemblies is of the same construction. Each rod carrier assembly includes a chain span bar 58 having a transversely elongated main body portion 58a. A transversely centrally located lug 58b is joined to portion 58a to extend thereabove while end lands 580 are joined to the opposite ends of a main body 580 to extend thereabove. To each end land 580 there is bolted a drag lug 59 to be located thereabove and extend transversely outwardly therefrom, the transverse outer end portions of the lugs 59 being transversely spaced from one another a distance greater than the spacing of the adjacent vertical edges of the end plates 41. The transversely remote edges of the lugs of each assembly 57 is less than the spacing of the portions of the rod 45 that are to be coated. Each lug 59 has a rear vertical edge 59a, a top, upwardly and rearwardly inclined edge 5911, a top, rear, generally planar surface 590, and a depressed top front surface portion 59b, and a land 59e projecting upwardly from surface 59d to extend higher than surface 59c by a distance of about one-half the thickness of the rod 45. Each of the end lugs is secured to a plate 60 which in turn is secured to the adjacent link 30a of the adjacent chain 30 in a manner, for example, flat head screws. so as not to interfere with the movement of the chains over the sprockets. As may be noted from FIG. 5, when the rod carrier assemblies are mounted on the chains, the lands 59c extend to an elevation just slightly below the bottom edges of the front plates 41 and to a higher elevation than the top surfaces of the legs 50a while the lug top surfaces 59c is at a slightly higher elevation than the top surfaces of the legs 50a. The inclined surfaces 59b facilitate the drag lugs forcing the rods in the hopper upward slightly to permit the drag lugs moving thereunder, other than for lands 59e which will abut against the forward edge of the lowermost rod in the hopper for moving the rod out of the hopper. In order to retain the rod on the rod carrier as it moved away from the hopper, adjacent each end portion 58c of the span link and on the span link, there is mounted a permanent magnet 61. The magnets have top surfaces that are at substantially the same elevation as the top surfaces 590 of the drag links. Accordingly, the magnets will retain a rod with its flat surface in abutting relationship with the top surface 59:.  
  Referring now to FIGS. 1 and 6-9, the rod coating fluidizing bed assemblies, generally designated 64 and 65 respectively, will now be described. Each of the assemblies 64, 65 is bolted to a slide bar 66 which in turn slidably extends between parallel guide bars 68. The guide bars are secured to a bracket 67 in fixed positions while bolts (not shown) are extended through bars 68 and adjacent transversely elongated slots (not shown) in bracket 67 to permit limited transverse adjustment of the respective assemblies 64, and retain the assemblies in fixed adjusted positions on bracket 67. Bracket 67 is secured to the intermediate uprights 19.  
  Since each of the assemblies 64, 65 is of the same construction, other than they are oppositely faced, for the most part. only assembly 65 will be further described. Assembly 65 includes base plate 74 that forms a chamber 75 which is enclosed other than at the top and for an auger tube opening. The chamber extends around three sides of the base plate block portion 74a which has a vertical, auger tube aperture 76 extending therethrough. Bolted to the base plate to extend thereabove are a front plate 78, a pair of longitudinally spaced transversely inwardly side plate portions 79, and rear and front plates 80 that are joined together to provide a chamber 84 for fluidized bed particles which is open at the top, and the bottom and between adjacent vertical edges of the side plate portions. A fluidized bed, air permeable membrane 81 is mounted between the base plate and members 78-80 to form the bottom of particle chamber 84 and close the top of chamber 75 other than for the membrane auger tube aperture that is aligned with aperture 76. A support plate 82 is bolted to block portion 74a with the membrane extending therebetween, the support plate having an auger tube aperture 83 extending therethrough that is aligned with the membrane aperture.  
  Bolted to the base plate to extend thereabove and to the adjacent vertical edge portions of the side plate portions 79 to extend toward the side plate 78 are a pair of longitudinally spaced vent plates 85. An end plate 86 is bolted to the vertical edges of plates that are opposite side plate portions 79 and is bolted to the base plate.  
  Each of the vent plates 85 has a vertically elongated groove 87 that opens tranversely outwardly in a direction away from the other vent plate. In each of the grooves, there is slidably mounted a gate 88 that has a vertically elongated slot 90 formed therein to permit limited vertical adjustment of the gate. A screw and wing nut 89 are provided with the screw being secured to the vent wall 85 and extending through the slot 90. Thw wing nut upon being tightened will retain the gate in a selected vertical fully adjusted position relative the respective vent wall. Additionally, each vent wall is provided with a vertically extending channel 92 that opens longitudinally outwardly toward the adjacent vent plate 85, opens downwardly, and terminates a short distance above the bottom edge of the vent plate.  
 A diagonally elongated material discharge slot 93 that i is inclined upwardly toward end plate 86 is provided in each of the vent plates to open to the respective channel 87 and channel 92, the gate 88 being adjustable to partially, or completely block the slots 93 to block material flow from the material chamber to discharge downwardly through channel 92. Thus slots 93 opens toward one another into the space provided between the vent plates while the lower terminal edges 88a of the gates are inclined at the same angle as slots 93. The membrane and base plate each have a cutout ofa shape to form a downward continuation of space between the adjacent vertical edges of plate portions 79, vent plates 85 (including that of channels 92), and end 86 to provide a rod coating channel 95. The chamber 75 has branches longitudinally on the remote sides of the vent plates from one another at a lower elevation than the vent plates for passage of air upwardly adjacent the inlets of the slots 93. The channel 95 is of a longitudinal length that is slightly greater than the thickness of the rod 45 (other than adjacent channels 92 and therebeneath) and a transverse dimension greater than the length ofa rod end portion that is to be coated whereby the rod end portion can be moved vertically through the aforementioned channel from a height above the respective rod coating assembly to a lower elevation than the rod coating assembly.  
  The base plate 74 dependingly mounts a pair of brackets 96, 97 which in turn respectively mount cooperating trough members 98, 99 to receive power that falls by gravity flow from the discharge slots 93. The trough 99 extends to a higher elevation than through 98 and includes an inclined wall 99a that is tapered in a downward direction toward trough 98 and longitudinally spaced end walls 99b that have vertical terminal edges. Similarly, the wall 98 includes an inclined wall 98a tapered in a downward direction toward trough 99 and longitudinally spaced end walls 98b that have vertical terminal edges adjacent trough end walls 9%. The top edge of wall 98a is at a lower elevation than the top edges of the side walls 98b and is integrally joined to a chute 100 that is inclined downwardly in a direction away from trough 99 so that excess material in the troughs 98, 99 overflows to discharge through the chute 100. The vertical terminal edges of the end walls 98b, 99b are spaced by a distance slightly greater than the thickness of the rod 45 so that the rod can be moved vertically downwardly therebetween, but otherwise minimizing the area between the troughs for discharge of powder between the troughs.  
  A mounting plate 106 is mounted by frame members 14 to mount a powder supply fluidized bed assembly. generally designated beneath the coating fluidized bed assemblies 64, 65. The horizontal cross-sectional area of the fluidized bed assembly 105 is many times greater than the horizontal cross-sectional area of assemblies 64, 65 and is provided to hold a supply of power and catch the powder that falls or discharged from the assemblies 64, 65. The assembly 105 includes a base that provides an open top air chamber 108, a rectangular frame 109 being secured to the base plate 110 with an air permeable membrane being secured between the frame 109 and the base plate 110. Thus the membrane 107 closes the open top of the air chamber of the base plate 110 and supports the powder within the frame 109 when no air under pressure being discharged into the chamber 108.  
  in order to retain a sufficient amount of powder in each of the assemblies 64, 65, each of the assemblies 64, 65 includes an auger tube 113 mounted by base plate 74 to extend through the aperture 76 and downwardly through the base plate 74 to terminate at an elevation above the membrane 107, but much more closely adjacent said membrane than the top peripheral edge of the frame 109. The auger tube extends upwardly in the chamber 84 to extend vertically more closely adjacent to the top horizontal edge of the vertical walls forming said chamber (except for cutout 124 which will be described below) than to membrane 81. The auger tube terminates at a somewhat lower elevation than the bottom edge of cutout 124. Rotatably extended within the auger tube. there is an auger shaft 114 that mounts a spiral auger blade 115 to extend closely adjacent to the top surface of the membrane 107. The spiral blade extends to the top of the auger tube. Shaft 114 extends upwardly of the auger tube and through a bracket 119 and the shaft mount 120 which rotatably mounts the auger shaft in a fixed axial position. The upper end of the shaft has a sprocket 121 keyed to, the sprocket being driven by a suitable source of power (not shown). Bracket 119 is mounted by a transverse bracket 118 that in turn is mounted by the intermediate uprights 19.  
  In order to control the maximum general level of fluidized powder in each of the fluidized bed assemblies 64, 65, each front wall 78 includes an upwardly opening cutout 124 that extends downwardly to an elevation that is slightly higher than the terminal edge of the auger tube 113. A gate 125 has a vertically elongated slot through which a screw 126 is extended, the screw being secured to wall 78 and having a wing nut threaded thereon for holding the gate in a vertically adjusted position on the front wall. Thus the elevation of the gate may be varied to within limits to control the general level of the powdered material in the respective assembly 64, 65; and thereby the head of powder that is discharged through the slots 93.  
  In order to automatically remove the rods from a carrier assembly, frame member 129 mounts transversely spaced, longitudinally elongated strippers 131 that extend upwardly and predominently rearwardly to terminate transversely between the sprockets 24 to intersect the path of travel of rods being carried by a carrier assembly and extend rearwardly transversely above an adjacent portion of the path of travel. Extending generally parallel to a slight distance below the strippers 131 are a pair of tracks 130 that are mounted by frame member 129. The rearward terminal ends of the tracks 130 are below the path of travel of the rods at a location just rearwardly of where the rods engage the strippers whereby the rod stripped from the carrier assembly will fall onto the tracks to be supported thereby. The tracks are transversely spaced to be in alignment with the notches 45a in the rods while each stripper is located transversely between the respective adjacent carrier assembly end portion and track. The vertical spacing of transversely aligned portions of the strippers and tracks is such to permit the rods being moved onto the tracks as mentioned hereinafter.  
  Since the notches extend more than half the width dimension of the rod, the center of gravity of the rod is more closely adjacent the edge of the rod through which the notches open than the opposite edge of the rod, and as the rods are being conveyed in a generally forward direction on the lower runs of the chains that the notches open in the direction of travel of the lower runs, as the rods are stripped from the carrier assembly, the rods in engaging the tracks, pivot on the tracks such that the plane of the width surface of the rod is inclined downwardly and forwardly relative the plane of the top surface of the tracks. As a result, as each succeeding rod is conveyed adjacent the last rod stripped from a rod carrier assembly, it engages the last rod to push said last rod forwardly and more nearly perpendicular to said track plane prior to the succeeding rod being stripped from the respective carrier assembly. As a result, all of the rods that have been coated are oriented in the same direction to have the notches point downwardly. To be mentioned is that the top portion of each track is, for a vertical dimension greater than the transverse dimension of a notch, of a smaller transverse dimension than the minimum transverse dimension of a notch (as being conveyed) to permit the rods pivoting in the above mentioned manner.  
  In order to heat the end portions of the rods prior to the end portions being moved downwardly through the coating channels 95 of the assemblies 64, directly above each of the channels there is mounted a heater 134. Each of the heaters 134 includes a high frequency heating element (not shown) on either side of the path of travel of the rod portions to be coated of the rods carried by the rod carrier assemblies. The heaters 134 are mounted by the bracket 118. A pair of post heaters 136 are mounted by brackets 137 which in turn are mounted by the bracket 67. The heater 136 are of substantially the same construction as heaters 134, other than that the temperature thereof is lower than that of the heaters 134. The heaters 136 are located a short distance forwardly of the sprockets 28 for heating both sides of the rod end portions as the rods are being conveyed by the chain lower runs toward the sprockets 24.  
  A blower 141 is mounted on a frame member 140 at a location for directing air onto the rod end portions after rod end portions have been conveyed through the heaters 136, to increase the rate of cooling of said rod portions.  
  In using the apparatus of this invention, a supply of rods 45 is placed in the hopper 33 with all of the notches all pointing in the same direction and the lowermost rod supported on the legs 50a of the brackets 50; a supply of powdered coating material is placed in the fluidized bed assembly 105, the drive to the augers is started; and air under pressure applied to each of the air chambers of the fluidized bed assemblies 64, 65 and 105. The augers in rotating elevate the powder material from adjacent membranes 108 and through the tubes 113 to flow over the top terminal edges of said tubes and descend in the chambers 84 of the assemblies 64, 65. As a result of air under pressure being discharged into chambers 75, the coating material in chambers 84 is fluidized. The continuing of elevating of the powder through the auger tubes results in the fluidized material level building up in chambers 84 until it overflows the top terminal edges of gates to flow under gravity back into the top chamber of the fluidized bed assembly 105. Due to the fluidization of the material in assembly 105, the level of powder contained therein is maintained at a generally level so that there is a constant supply adjacent the auger tube inlets to be elevated by the auger.  
  After sufficient powder has been elevated into the assembly 64, 65 so that the level of fluidized powder therein is generally at the level of the top edge of the gate 125, the gates 88 are adjusted to permit the appropriate amount of powder flowing through the slots 93 to be discharged therefrom and flow downwardly through the troughs 99, 98. The powder in being discharged from the adjacent slots 93 of each assembly 64, 65 comingles as it falls. The rate of discharge of powder through the slots 93 is sufficiently great that the level of the powder builds up in the troughs 98, 99 to an elevation substantially above the bottom edge of a trough wall 99a. To be mentioned is that the rate of feeds of the augers to chambers 84 is greater than the rate of discharge of powder through the slots 93.  
  Now the drive to the driven one of the shafts 23, 25, 27 is started to move the upper runs of the chains 30 in a rearward direction. This moves a rod carrier assembly beneath hopper 33 such that the inclined edges 59b of the lugs 59 force the bottommost bar in the hopper upwardly a slight amount so that the lugs move thereunder. The magnets provided on the span bar tend to move the rods out of the hopper; however, spring 52 provides sufficient resistance to the movement of the bottom rod away from the vertical legs of brackets 50 that the bottom rod is retained in a position that the drag links and magnets move relative the rod until lands 59c abut against the front edge of the rod. At this time, lands 59c provide a sufficient withdrawal force to move the bottom rod out of the hopper against the resistance of the springs 52 while the magnets retain the rod on the rod carrier assembly in abutting relationship to the lands 59c. As the rod carrier assembly with a rod thereon is moved rearwardly by the chains to pass over the sprockets 26 and thence downwardly so that the end portions of the rods are conveyed between the heater elements of the heaters 134, the radio frequency heaters heat the end portions of the rods to be coated to a temperature substantially above that which the powder melts, for example 800F. The rod carrier assembly then conveys the rod downwardly so that the rod end portions move through the coating channels 95 of the assembly 64, 65 respectively. As the rod end portions move downwardly between the slots 93, the powder impinges on each side of the rod causing a flowing action whereby each side and the top of the respective rod end portion melts the powder impinging thereon to coat the rod end portions. As the rod end portions move downwardly between the troughs 98, 99, the then bottom edges of the rod end portions move through the powder in the troughs to coat the bottom edges thereof. At the time the rod end portions are at the elevation of the slots 93, the temperature thereof is still sufficiently hot to melt the powder particles, for example 525F.  
  After the rod having the coated end portions has been moved downwardly around the sprockets 28, the end portions are passed through the radio frequency post heaters 136 that heats them to a temperature of about 200300 to melt the small particles that stick on the coated end portions whereby a smooth coating is obtained. Thereafter, the rod carrier assembly carries the rod passed the blower 141 to cool the rod end portions. it is to be noted that at this time the rod is being dependingly carried by the rod carrier assembly, however, it is retained on the rod carrier assembly solely by the magnetic force of the magnets. Thereafter, the lower runs of the chains move the rod carrier assembly to the sprockets and thence move the rod to contact the strippers 131 which strip the rod from the rod carrier assembly in a manner previously indicated.  
  As an example of one embodiment of the invention, the apparatus thereof may be of a length of approximately 8 feet; the spacing of the central axes of shafts 25, 27 about 4 feet; and the rod carrier assemblies on the chains for conveying the hanger rods spaced one inch apart and moving at the rate of 15 feet per minute. As a result, 180 rods per minute may be coated, with this particular embodiment.  
  To be noted with the present invention, the coating material does not have to be in a liquid condition, and thus avoids having to provide a liquid container and heating of such a container. Additionally, with the rod carrier assemblies of this invention, provision is made for coating both end portions of the rod without the rod carriers assemblies having any moving parts. Further, since only the end portions are coated, less coating material is utilized than if the whole rods were coated. Additionally the powder discharged through slots 93 that does not adhere to the rods at the heated end portions thereof, is automatically recycled.  
  Further, since the powder is of a nature that if the material in the chamber formed by frame 109 and membrane 107 were not fluidized, in a short interval of time the supply of powder adjacent the auger tube inlets would be quickly depleted even though there was a considerable amount of powder piled up in the chamber remote from the auger tube inlets. However, due to fluidizing the material, the material in the chamber remains at a nearly constant, though gradually decreasing, level throughout the chamber even though powder is continuously being removed from the chamber.  
  Also, due to the fluidization of material in the powder chambers of assemblies 64, 65, the powder remains at a nearly constant level whereby a nearly constant head of powder is obtained at slots 93 which facilitates obtaining an even coating of substantially the same thickness characteristics on each of the rod ends.  
 What is claimed is:  
  1. Apparatus for coating an end portion of a rod, comprising a frame, a rod hopper assembly mounted on the frame for holding a supply of rods in a condition to have one rod at a time removed therefrom, means for fluidizing rod end coating powder and discharging the powder to fall under gravity flow in a predetermined powder flow path, said fluidizing means being mounted on the frame, a rod carrier assembly for removing a rod from the hopper assembly and supportingly retain the removed rod thereon as the rod end portion is being coated, and endless conveyor means mounted on the frame and mountingly moving the rod carrier assembly adjacent the hopper assembly to remove a rod from the hopper assembly and thence moving the rod carrier assembly to move the rod end portion in said powder flow path to have powder impinge thereon, said fluidizing means including a rod coating fluidized bed assembly mounted on the frame that has a powder discharged portion for discharging powder to fall through said powder flow path, said fluidized bed assembly having a fluidized powder chamber, and means for containing a supply of powder mounted on the frame beneath said fluidized bed assembly for catching powder discharged therefrom and containing a supply of powder, said powder supply means including a fluidized bed member having a chamber for containing powder in a fluidized condition and means for elevating powder from the powder supply means chamber to the bed assembly powder chamber.  
  2. The apparatus of claim 1 further characterized in that the fluidizing means includes a second fluidized bed assembly mounted on the frame for discharging powder through a second powder flow path to the supply means for impinging on the rod other end portion as the rod is being carried by the rod carrier assembly. said second assembly having a powder chamber and means for elevating powder from the supply means to the last mentioned chamber.  
  3. Apparatus for coating an end portion of a rod. comprising a frame, a rod hopper assembly mounted on the frame for holding a supply of rods in a condition to have one rod at a time removed therefrom, means for fluidizing rod end coating powder and discharging the powder to fall under gravity flow in a predetermined powder flow path, said fluidizing means being mounted on the frame, a rod carrier assembly for removing a rod from the hopper assembly and supportingly retain the removed rod thereon as the rod end portion is being coated, and endless conveyor means mounted on the frame and mountingly moving the rod carrier assembly adjacent the hopper assembly to remove a rod from the hopper assembly and thence moving the rod carrier assembly to move the rod end portion in said powder flow path to have impinge thereon, said fluidizing means includes a fluidized bed assembly having means for defining a fluidized powder chamber, the last mentioned means including wall portions defining a vertical elongated channel that is generally U-shape in horizontal cross section, said wall portions including spaced, opposite vertically elongated vent walls having lower end portions, each of said lower end portions having a discharge slot opening to the powder chamber and to said channel to discharge powder to flow through said powder flow path.  
  4. The apparatus of claim 3 further characterized in that the chamber means includes a wall having a discharge opening that has a bottom edge at a substantially higher elevation than said discharge slots and a gate mounted on said wall for limited vertical adjustment to selectively vary the minimum effective elevation of the discharge opening and that the fluidizing means includes supply means mounted on the frame beneath the fluidized bed assembly and having a powder chamber to catch powder discharged through said slots and the discharge opening, the last mentioned powder chamber being of a substantially larger capacity than the first mentioned powder chamber, and means for continuously elevating powder from the supply chamber to the assembly chamber.  
  5. The apparatus of claim 4 further characterized in that the rod carrier assembly is of a substantially shorter transverse than the rod carried thereon to have the rod end portion extend transversely outwardly of the rod carrier assembly, and that there is provided first heater means on the frame for heating the rod end portion prior to the rod end portion being moved into the fluidized bed channel to a sufficiently high temperature to melt the powder the adhere to the rod when the powder impinges on the rod end portion in moving through said path of movement, and post heater means for heating the rod end portion after it has moved into and thence remote from said path of movement to heat particles adhering to the coating sufficiently to flow to provide a smooth coating.  
  6. The apparatus of claim 4 further characterized in that said supply means includes a fluidized bed assembly having a chamber for containing powder in a fluidized condition and that the elevating means includes auger means extending into the last mentioned chamber for elevating powder therefrom.  
  7. The apparatus of claim 4 further characterized in that there is provided trough means on the frame vertically beneath said channel and in said path of movement for aiding in coating the lowermost part of the rod end portion as the rod end portion is moved therethrough, said trough means having narrowly horizontally spaced portions providing a generally vertical slot for the rod end portion to move through as the rod on the rod carrier assembly is being conveyed by said conveyor means.  
  8. The apparatus of claim 4 further characterized in that said conveyor means includes longitudinally elongated runs, said rod carrier assembly being mounted on the conveyor means to along the upper runs extend thereabove and having magnetic means for releasably holding a rod to extend transversely to said runs.  
  9. The apparatus of claim 8 further characterized in that the rod carrier assembly, when on the upper runs, includes transversely spaced drag link portions having top rod supporting surface portions and a land extending higher than said surface portions by a distance less than the height of a rod being at least partially supported by said surface portions and rearwardly of said surface portions relative the normal direction of movement of the upper runs.  
  10. The apparatus of claim 9 further characterized in that the hopper assembly extends to a higher elevation than the upper runs and includes leg means for supporting a rod in a position to be engaged by the rod carrier land and removed therefrom as the rod carrier assembly is moved by the conveyor means and spring means abuttable against the rod to resist movement of the rod off the leg means until the rod abuts against the land.  
  11. Apparatus for coating the end portion of a rod with a powder that upon heating and thence cooling forms a solid continuous film adhering to the rod end portion to coat the rod end portion comprising a frame, a rod hopper assembly mounted on the frame for holding a supply of rods in a condition to have one rod at a time removed therefrom, means mounted on the frame for discharging powder to fall under gravity flow in a predetermined powder flow path, a rod carrier assembly for removing a rod from the hopper assembly and supportingly retain the removed rod thereon as the rod end portion is being coated, driven endless conveyor means mounted on the frame for mounting the rod carrier assembly and moving the rod carrier assembly adjacent the hopper assembly to remove a rod from the hopper assembly and thence adjacent said powder flow path to have powder impinge on the end portion of the rod removed from the hopper assembly, and heater means mounted on the frame for heating the removed rod end portion to a temperature prior to powder in said flow path impinging on the rod end portion that the powder melts to form a coating film that adheres to the rod end portion, said carrier assembly including a drag link surface portion for abutting against the rod, a land portion projecting further from the conveyor means than said surface portion to transmit a removable force to the rod that is to be removed from the hopper assembly and magnetic means for holding the removed rod against said surface portion as the rod is carried by the rod carrier assembly.  
  12. The apparatus of claim 11 wherein the rod is a hanger file folder rod and the hopper assembly includes a plurality of rods in the same orientation, further characterized in that there is provided a plurality of rod carrier assemblies mounted in spaced relationship on the conveyor means, and stripper means for stripping rods having coated end portions one after another from the rod carrier assemblies as the conveyor means is being driven and support the stripped rods in the same orientation relative one another.  
  13. The apparatus of claim 12 further characterized in that said powder discharge means includes a fluidized bed assembly for fluidizing powder and discharging powder to flow through said path of movement.  
  14. Apparatus for coating the end portion of a rod with a powder that upon heating and thence cooling forms a solid continuous film adhering to the rod end portion to coat the rod end portion comprising a frame. a rod hopper assembly mounted on the frame for holding a supply of rods in a condition to have one rod at a time removed therefrom. means mounted on the frame for discharging powder to fall under gravity flow in a predetermined powder flow path, a rod carrier assembly for removing a rod from the hopper assembly and supportingly retain the removed rod thereon as the rod end portion is being coated. driven endless conveyor means mounted on the frame for mounting the rod carrier assembly and moving the rod carrier assembly adjacent the hopper assembly to remove a rod from the hopper assembly and thence adjacent said powder flow path to have powder impinge on the end portion of the rod removed from the hopper assembly. and heater means mounted on the frame for heating the removed rod end portion to a temperature prior to powder in said flow path impinging on the rod end portion that the powder melts to form a coating film that adheres to the rod end portion. said powder discharge means including a first fluidized bed assembly for fluidizing powder, said fluidized bed assembly including a fluidize bed air permeable membrane, wall portions extending above the membrane to cooperate therewith to form a fluidized particle chamber. the wall portions having top perimetric edge portions that at a minimum spacing from the membrane are a substantial distance above the membrane and a powder discharge slot vertically intermediate the membrane and the perimetric edge portions that opens to said chamber to discharge powder to flow through said path.  
  15. The apparatus of claim 14 further characterized in that wall portions include means defining a vertically extending channel that is generally U-shaped in horizontal cross section to have the rod end portion move therethrough, the last mentioned means including the above mentioned slot and a second discharge slot on the opposite side of the path of movement of the rod portion through the channel from the first mentioned slot.  
  16. The apparatus of claim 14 further characterized in that said powder discharge means includes a supply fluidized bed assembly mounted on the frame beneath the first fluidized bed assembly to catch powder discharged from the first fluidized bed assembly and means for continuously elevating powder from the supply fluidized bed assembly and discharging powder into the first fluidized bed assembly.  
  17. The apparatus of claim 16 wherein the rod has a second rod end portion, further characterized in that said powder discharge means includes a second fluidized bed assembly mounted on the frame above the supply fluidized bed assembly for discharging powder to flow through a path of movement to impinge on the second rod end portion when powder from the first fluidized bed assembly impinges on the first mentioned rod end portion.  
  18. The apparatus of claim 17 further characterized in that there is provided second heater means on the frame for heating the removed rod second end portion to a temperature prior to powder impinging on the rod second end portion that the powder melts to form a coating film that adheres to the rod second end portion, that the second fluidized bed assembly includes an air permeable membrane, wall portions extending above the membrane to cooperate therewith to form a fluidized particle chamber, said wall portions having top perimetric edges at a minimum spacing from the membrane that is a substantial distance above the membrane. and a powder discharge slot vertically intermediate the membrane and the perimetric edge portion most closely the membrane that opens to said chamber to discharge powder, the last mentioned wall portions including a vertically extending channel that is generally U-shaped in horizontal cross-section to have the rod second end portion move therethrough and opens toward the first mentioned channel.  
  19. In apparatus for coating an end portion of an elongated rod comprising a frame. a rod hopper assembly mounted on the frame for holding a supply of rods in a condition to have one rod at a time removed therefrom, an elongated rod carrier assembly for removing a rod from the hopper assembly and supportingly retain the removed rod thereon, said rod carrier assembly being of a maximum transverse dimension that is substantially less than the transverse dimension of said rod, endless conveyor means mounted on the frame and mountingly moving the rod carrier assembly adjacent the hopper assembly to remove a rod from the hopper assembly and thence moving the rod carrier assembly through a predetermined path of travel. said conveyor means including a longitudinally extending upper run and a pair of transversely spaced link chains mounting said rod carrier assembly transversely centered relative the hopper assembly when the rod carrier is therebeneath, the hopper assembly including leg means for supporting a plurality of vertically stacked rods above the upper run portion to extend transversely to the upper run, and means permitting only one rod at a time being removed from the leg means and yieldably resisting the removable of the rod from the leg means, the rod carrier assembly being mounted on the conveyor means to extend transversely relative thereto and when on the upper run having a transversely elongated rod carrier, magnetic means for supportingly engaging the lowermost rod in the hopper assembly and land means extending higher than the magnetic means for abutting against the part of the lowermost rod in the hopper assembly on the side opposite the direction of movement of the upper run to force a rod off the leg means against said resisting means, said rod carrier having top surface end portions on opposite transverse sides of the magnetic means that extend about the same elevation as the magnetic means for supporting rod portions and forwardly of the land means in the direction of travel of the upper run, and a pair of fluidized bed assemblies mounted on the frame for discharging a coating powder onto the rod end portions of the rod carried by the rod carrier assembly at a location remote from the hopper assembly as said chains convey said rod carrier assembly and heater means mounted on the frame for heating the rod end portions prior to having powder discharged thereon to a sufficiently high temperature that the powder forms a coating film thereon as the powder is discharged onto said end portions.  
 UNITED STATES PATENT OFFICE CEHMCATE CF l r&#39;i l PATENT NO. 3,880,113  
 DATED April 2.9, 1975 INVENTORtS) Robert J. Mueller et 211.  
  It is certrtied that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below;  
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