Abstract:
A conveyor apparatus, supporting racks and heating arrangement for heating and cooling work pieces such as magnet assemblies for rotating electric machines. Because of the closed oval path through which the work pieces are transported on the racks by means of a conveyor mechanism that does not have to support the weight of the work pieces, very high efficiencies can be obtained.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates to a drying apparatus and a conveyor for use therein and article supporting rack therefore that provides a very compact and effective arrangement for drying articles such as components of rotating electrical machines.  
           [0002]    In assembling electrical machines such as electric motors or generators, a plurality of magnet segments are affixed to a cylindrical surface of an outer case. A cylindrical retainer case is fitted to the outer case to hold these magnets in place so that they are trapped between the inner and outer cases. The outer case generally is comprised of a cylindrical shell that is open at one end. The other end is closed by an end plate having a cylindrical opening at its center. The magnets are bonded with an adhesive between the inner and outer cases.  
           [0003]    In the process of forming these magnets assemblies, it is the practice to cure the adhesive through a drying operation where the components are heated at a high temperature for a predetermined time period.  
           [0004]    Conventionally, this heating and bonding operation takes place on a belt conveyor or roller conveyor where the work pieces are transported by the conveyor to a drying chamber and retained therein for a given period of time for the heat to dry the adhesive. However, when the work pieces are mounted side by side on a conveyor in this fashion, there is a limit to the number that can be placed in the drying chamber and the heating of the work pieces is not necessarily uniform. Furthermore, it is difficult to seal the area containing the conveyor and this results in poor thermal efficiency. In addition, the power to drive the conveyor becomes quite large since it supports the weight of the work pieces and thus, the system is quite cumbersome and inefficient. Furthermore since the work pieces are conveyed in a linear manner the return flight of the conveyor does no real work and the spatial requirements are large.  
           [0005]    It is, therefore, a principal object to this invention to provide an improved, compact and highly effective apparatus for heat drying work pieces.  
           [0006]    It is a further object to this invention to provide an arrangement for heat drying the work pieces where they are not only heated but cooled so that they can be readily placed into the heating chamber and removed there from.  
           [0007]    It is a still further object to this invention to provide an improved conveyor mechanism that lends itself to a continuous process and wherein the work pieces can be easily placed on the conveyor and removed from the conveyor without requiring high driving forces for the conveyor.  
           [0008]    It is further object to this invention to provide an improved rack arrangement for holding these types of work pieces and conveying them through the heating and cooling chambers.  
         SUMMARY OF THE INVENTION  
         [0009]    A first feature of the invention is adapted to be embodied in a drying apparatus comprising a conveyor for conveying articles along a closed path. An enclosure encloses a substantial portion of the closed path and leaves at least one open area through which articles to be dried can be inserted on the conveyor and dried articles can be removed from the conveyor. A heater heats at least a portion of the closed path enclosed by the enclosure for drying articles on the conveyor.  
           [0010]    Another feature of the invention is adapted to be embodied in a drying apparatus as set forth above and employs a conveyor that is generally oval in top plan view having a straight downstream path and a straight return path joined at opposite ends by curved portions.  
           [0011]    Still another feature of the invention is adapted to be embodied in a drying apparatus as set forth above and employs a heater that heats atmospheric air and delivers it to at least a part of the enclosed area through louvered walls of the enclosure.  
           [0012]    Yet another feature of the invention is adapted to be embodied in a drying apparatus as set forth above and employs a conveyor that comprises a flexible transmitter and the articles to be dried are carried by racks supported on a floor positioned below the flexible transmitter and driven by the flexible transmitter.  
           [0013]    Another feature of the invention is adapted to be embodied in a conveyor for conveying articles between a plurality of stations comprising a flexible transmitter positioned above a workplace floor and a plurality of racks supported on the floor and driven by the flexible transmitter. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0014]    [0014]FIG. 1 is a cross sectional view looking from above of a heat drying apparatus and conveyor system constructed in accordance with an embodiment of the invention.  
         [0015]    [0015]FIG. 2 is a side elevational view of the apparatus looking in the direction of the arrow  2  in FIG. 1.  
         [0016]    [0016]FIG. 3 is an end elevational view of the apparatus taken from the loading and removing end shown to the left in FIGS. 1 and 2.  
         [0017]    [0017]FIG. 4 is a top plane view of one of the racks with its connection to the conveyor being shown in broken lines.  
         [0018]    [0018]FIG. 5 is a front elevational view of the rack.  
         [0019]    [0019]FIG. 6 is a partially schematic view showing how the closure doors of the heating and cooling apparatus are operated. 
     
    
     DETAILED DESCRIPTION  
       [0020]    Referring now in detail to the drawings and initially primarily to FIGS. 1 through 3, a heat drying and cooling apparatus constructed in accordance with an embodiment of the invention is identified generally by the reference numeral  11 . The apparatus  11  includes a conveyor apparatus, indicated generally by the reference numeral  12  that conveys a plurality of work pieces, shown in phantom in FIGS. 4 and 5 and indicated generally by the reference numeral  13 ,that are mounted on rack assemblies, indicated generally by the reference numeral  14 , through a housing assembly, indicated generally by the reference numeral  15 .  
         [0021]    The housing assembly  15  includes a first more highly insulated portion  16  that has a generally L-shape in top plane view and a second, less highly insulated portion  17 . The portion  17  protrudes at one end and has work piece insertion openings  18  and dried work piece removal openings  19 . The work pieces  13  are placed upon the racks  14  through the opening  18  for heat drying and subsequent forced cooling and removed there from through the opening  19 The housing assembly  15  is adapted to be placed upon a floor  21  of a factory and is supported in elevated location relative location thereto by a plurality of spaced supporting legs  22  that have adjustable leveling bases  23 . Thus, the openings  18  and  19  are positioned in a convenient location and are easily accessible by workmen.  
         [0022]    The conveyor assembly  12  is comprised of a pair of posts or shafts  24  and  25  that are rotatably journalled about vertical axes. A pair of driving sprockets  26  are affixed at axially spaced locations to the drive shaft  24  which is driven by an electric drive motor  27  mounted beneath the housing  15 . The remaining shaft  25  carries like idler sprockets. A pair of conveyor chains  28  is driven by the sprockets  26  and they and the idler sprockets carried by the shaft  25  define a generally oval path of travel of the conveyor assembly  12 .  
         [0023]    This oval path defines a pair of longitudinally extending parallel paths comprising a feed path for conveying the racks  14  first through the highly insulated portion  16  and specifically the interior cavity  29  thereof. A small portion of the return path extends though a shorter side  31  which is also heated. Openings are formed in end walls of these two heated and more highly insulated portions of the housing  16 . These openings are sequentially opened and closed by an admitting door  32  and a removal door  33  which are operated in a manner which will be described later by reference to FIG. 6.  
         [0024]    A plurality of drive arms or links  34  are affixed at spaced locations to the chains  28  and are connected to the racks  14  in a suitable manner so that the racks  14  will move through a path that also has an oval configuration. Thus the racks  14  and supported work pieces will be moved through the heating chambers  29  and  31 , through a cooling chamber  35  formed at one side of the housing portion  17  and which terminates in a cavity  36  that is accessible through the openings  18  and  19 .  
         [0025]    Referring now specifically to the construction of the racks  14 , these are provided with four corner posts  37  and support plates  38  that extend there between and are affixed thereto. Each of these support plates  38  has a generally H-shaped configuration with a raised central part  39 . This raised central part  39  is complimentary to an opening  41  formed in a partially closed end  42  of the work piece  13 . The upper end of the work piece  13  is opened as aforedescribed. Thus, by virtue of this construction, the work pieces will all be uniformly heated and cooled when passing through the housing assembly  15 . Recesses  42  in the plates  38  affords good air circulation around the work pieces  13  while providing relatively rigid holding of the work pieces during their travel.  
         [0026]    Each rack  14  is supported on a floor  43  of the housing assembly  15  by means of rollers or wheels  44  that are journalled on shafts  45  fixed at the lower end of support legs  46 . As a result, the work pieces  13  and racks  14  are not supported by the conveyor assembly  12 . Thus, the driving force of the chains  28  is substantially reduced and therefore the system can be operated very inexpensively. In addition, since the conveyor  12  consisting of the chains  28  and rack driving arms  34  is quite small, the heated area comprising the chamber portions  29  and  31  can be well insulated and operate at a high efficiency  
         [0027]    The manner in which the chamber comprising the portions  29  and  31  is heated will now be described by primary reference to FIGS. 1 through 3. The side walls of the housing portion  16  are provided with louvered openings  47  that best appear in FIG. 3. Ducts  48  enclose these louvered openings  47  and have a generally rectangular configuration with a downwardly tampering section for a reason which will become apparent shortly.  
         [0028]    Hot air is delivered to each of the ducts  48  by a blower and heater system that includes a common atmospheric air intake  49  having a flow control valve  51  therein. This common intake  49  feeds an inlet duct  52  associated with each of a plurality of blowers each contained within a blower housing  53  and driven by a respective electric motor  54 . The blower housings  53  have outlet ports  55  that communicate with heating chambers  56  at the inlet end of each duct  48  and which are provided with electric heaters  57 . In addition, return passageways  58  communicate with a return duct  59  for returning excess heated air back to the inlet section  49  downstream of the control valve  51 . In this way, the temperature can be accurately controlled.  
         [0029]    Because the ducts  48  have a tampering side wall the flow area to the lowermost louvers  47  is less than that to the uppermost louvers  47 . Hence there will be a uniform flow velocity through each louver  47  to provide uniform heating of the work pieces  13  supported on the racks  14 .  
         [0030]    The work pieces  13  are delivered to the heating chambers  29  and  31  by opening of the door  32  and then closing it after the next series of racks  14  has been moved into position in the heating chamber. From these heating chambers  29  and  31 , the racks are discharged by opening the door  33  and permitting the racks to pass into the cooling chamber  35 .  
         [0031]    Cool atmospheric air is delivered to this chamber  35  by means of a further blower motor  61  that is positioned beneath the housing assembly  15  and which blows atmospheric air into the chamber  35  through a feed duct  62 . Thus, by the time the work pieces  13  have been progressed to register with the opening  19 , the work pieces  13  will be cooled and can be easily removed from the racks  14 .  
         [0032]    The mechanism for opening and closing the doors  32  and  33  is illustrated in FIG. 6. This includes a hydraulic or pneumatic cylinder  63  that has its piston rod  64  connected to the shaft  65  of a pulley  66 . A drive cable  67  is fixed at one end to a fixed abutment  68  and as the piston rod  66  reciprocates in the direction of the arrow A, the drive cable  67  will raise or lower doors  32  and  36  in the direction shown by the arrow B as the drive cable  67  passes over the pulley  66  and fixed axes pulleys  69  and  71 .  
         [0033]    Thus, it should be apparent that the conveyor mechanism, racks and heating and cooling arrangement provides a very compact assembly wherein a number of work pieces can be heated uniformly and then cooled so that they can be easily inserted and removed from their supporting racks  14 . Of course, the structure described represents preferred embodiments of the invention and various changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims.