Abstract:
A magnetic separator for spacing a plurality of workpieces in face-to-face relationship includes upper and lower guide plates that define a passage having an inlet opening and an outlet opening for workpieces moving through the separator, with the inlet opening having a funnel-shaped configuration adapted to admit and align any misaligned workpieces moving into the passage. Upper and lower pole pieces adjacent the upper and lower guide plates provide a magnetic field operative to orient workpieces in the passage. The upper guide plate has an intermediate portion that extends between an inlet and outlet end portions of the upper guide plate, with the inlet end portion extending transverse to the intermediate portion of the upper guide plate. The passage has an intermediate portion disposed between the inlet opening and outlet openings, with the inlet opening being substantially larger in cross-sectional area than the intermediate portion of the passage.

Description:
RELATED APPLICATIONS 
     This application is a continuation application of currently pending U.S. application Ser. No. 10/780,984, filed on Feb. 18, 2004 for ADJUSTABLE MAGNETIC SEPARATOR, which claims the benefit of U.S. Provisional Patent Application No. 60/481,241 filed Aug. 16, 2003, the entire disclosures of both of which are fully incorporated herein by reference. 
    
    
     BACKGROUND 
     The present invention relates to a magnetic separator that is especially adapted to separate plate-like metal objects such as metal can lids, also known as “closures” or “ends”. 
     Closures for metal beverage containers are generally of a circular shape with a flanged perimeter called a curl. The closures, or ends, are usually made of aluminum or steel, and the curl is used in attaching the end to a can body through a seaming operation. To aid the integrity of the seal thus formed between the can body and the end, it is a common practice to apply a bead of sealant or adhesive (“compound”) within the curl during manufacture of the end. Different types of coatings are also selectively or generally applied to can ends and can bodies for various other purposes as well, for example, to repair damaged coatings. For the purposes of the present description, coatings, sealants and adhesives are all considered to be “liquids” applied to a workpiece. 
     It is necessary in this manufacturing operation to cure or dry such liquids. It is known to dry can ends by infrared radiation, convection heating, or induction heating. 
     An induction heater, for example, typically includes a cabinet that supports a tube extending generally horizontally across the cabinet from one end to the other. An induction coil is wrapped around the tube. The ends move through the tube in a stacked relationship, that is, with abutting face-to-face contact with each other. When a suitable current is passed through the coil, the metal can ends are inductively heated. The heat is transferred to the compound on the can ends by conduction. The compound is heated and water is driven off from the compound into the surrounding air. 
     When the can ends exit the dryer, the compound on the can ends is substantially dry. A small amount of moisture may still be present in the compound, however. In addition, the can ends exit the dryer in a condition stacked adjacent each other (in a “stick”). Therefore, it is known to provide a magnetic separator at the outlet end of the dryer. The separator separates the can ends from each other by a small space, for example, one quarter inch. This separation facilitates final drying of the compound on the can ends. This separation also facilitates the grabbing of the can ends individually by a rotating wheel at the outlet end of the separator, as is necessary for further use and processing of the can ends. 
     The stick of ends coming into the inlet end of the separator may include some ends that stick up from the others. In some prior art separators, this can cause jamming or other problems. 
     The can ends are guided through the separator by upper and lower guide members that are solid metal pieces and therefore block the view of the pole plates. This can make it more difficult to adjust accurately the position of the pole plates, which determines magnetic strength. 
     In the prior art separator, the steps needed to adjust the vertical positions of the guide plates and the pole pieces can be tedious and may need to be repeated to set the adjustment properly. In addition, the upper guide plate is not easily removable to gain access to areas of the separator. 
     SUMMARY 
     The present application relates to a magnetic separator having for metal objects such as metal can lids, also known as “closures” or “ends”. In one aspect of the invention, the separator has an inlet opening that is adapted to admit and align any misaligned workpieces moving into the separator. This may be accomplished by providing an upper guide plate with a funnel-shaped configuration. 
     Accordingly, in one inventive embodiment of the present application, a magnetic separator for spacing a plurality of workpieces in face-to-face relationship includes upper and lower guide plates that define a passage having an inlet opening and an outlet opening for workpieces moving through the separator, with the inlet opening having a funnel-shaped configuration adapted to admit and align any misaligned workpieces moving into the passage. Upper and lower pole pieces adjacent the upper and lower guide plates provide a magnetic field operative to orient workpieces in the passage. The upper guide plate has an intermediate portion that extends between an inlet and outlet end portions of the upper guide plate, with the inlet end portion extending transverse to the intermediate portion of the upper guide plate. The passage has an intermediate portion disposed between the inlet opening and outlet openings, with the inlet opening being substantially larger in cross-sectional area than the intermediate portion of the passage. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features of the present invention will become apparent upon consideration of the following description of the invention with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of a separator in accordance with one embodiment of the invention, taken from a front or outlet end of the separator; 
         FIG. 2  is a perspective view of the separator of  FIG. 1 , taken from a back or inlet end of the separator; 
         FIG. 3  is a front elevational view of the separator of  FIG. 1 ; 
         FIG. 4  is an enlarged front elevational view of portions of the separator of  FIG. 1 ; 
         FIG. 5  is a side elevational view of the separator of  FIG. 1 , with some parts broken away; 
         FIG. 6  is a schematic side view of a portion of the separator of  FIG. 1  showing a plurality of workpieces in the separator; and 
         FIG. 7  is an enlarged side elevational view of the a portion of  FIG. 1 , with some parts broken away. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention relates to a magnetic separator for plate-like metal objects such as metal can lids, also known as “closures” or “ends”. The invention is applicable to separators of differing constructions. As representative of the invention,  FIGS. 1-7  illustrate a separator  10  constructed in accordance with one embodiment of the invention. 
     The separator  10  includes a frame  12 . The frame  12  includes two back uprights  14  and two front uprights  16 . The two back uprights  14  are located at the inlet end  18  of the separator  10 , and the two front uprights  16  are located at the outlet end  20  of the separator  10 . The uprights  14  and  16  provide the frame  12  with a generally rectangular configuration. The back uprights  14  enable the inlet end  18  of the separator  10  to be connected with the outlet of a dryer (not shown), such as an induction dryer. The uprights  14  and  16  have slots  22  for receiving fasteners in a manner slidable along the length of the uprights. 
     The frame  12  includes at least two sub-frames that interconnect the uprights  14  and  16 . One of the sub-frames  30  is located at the top of the separator  10 , and includes a cross-bar  32  that extends between the left and right sides. The sub-frame  30  is fixed in position on the uprights  14  and  16 . Another one of the sub-frames  34  is located part way down the uprights  14  and  16 , from the top. The sub-frame  34  is adjustably supported on the uprights  14  and  16  for vertical sliding movement along the uprights, in a manner as described below. 
     The separator  10  includes an upper M-channel, or guide plate,  40  and a lower M-channel, or guide plate  44 . The upper and lower guide plates  40  and  44  define between them a passage  41 . The passage  41  has an intermediate portion  43  disposed between an inlet opening  45  and an outlet opening  47 . The guide plates  40  and  44  guide movement of workpieces  48  ( FIG. 6 ) through the separator  10 , from the inlet opening  45  to the outlet opening  47 , along the passage  41 . 
     The separator  10  also includes an upper pole piece or magnet assembly  42 , and a lower pole piece or magnet assembly  46 . The upper and lower pole pieces  42  and  46  provide a magnetic field that supports and separates the workpieces  48  from each other as they move through the separator  10  from the inlet end  18  to the outlet end  20 . This separation assists in drying of the workpieces  48  and in proper removal of the workpieces from the separator  10  at the outlet end  20 . 
     The lower guide plate  44  has a generally M-shaped cross-sectional configuration, as best seen in  FIGS. 3 and 4 , including first and second side walls  50  and  52  that are interconnected by a V-shaped upper end wall  54 . The lower guide plate  44  has an intermediate portion  51  that extends between an inlet end portion  53  and an outlet end portion  55  of the lower guide plate. The inlet end portion  53  of the lower guide plate  44  extends parallel to the intermediate portion  51  of the lower guide plate. 
     A pair of first mounting brackets  56  adjustably connects the first side wall  50  of the lower guide plate  44  with the frame  12 . A pair of second mounting brackets  58  adjustably connect the second side wall  52  of the lower guide plate  44  with the frame  12 . As a result, the lower guide plate  44  is adjustably supported on the frame  12  so that it can be positioned at different vertical locations along the uprights  14  and  16 . This adjustment is not normally needed, since the lower guide plate  44  is set to the outlet of the dryer and it is the upper guide plate  40  that is adjusted when more or less space between the guide plates  40  and  44  is needed. 
     The lower pole piece  46  ( FIG. 4 ) includes a frame  60  that supports two permanent magnets  62 . The magnets  62  extend along the length of the separator  10 . The frame  60  is supported at each end on an adjustment screw  64  threaded in the lower guide plate  44 . The frame  60  and the adjustment screws  64  are thus supported on the lower guide plate  44 . 
     The heads of the adjustment screws  64  are accessible from underneath the lower pole piece  46  and the lower guide plate  44 . The separator  10  includes a lower cover  70  that has removable plugs  72  fitted in openings  74  in the lower cover. When one of the plugs  72  is removed as shown in  FIG. 4 , the head of the associated adjustment screw  64  is accessible. The adjustment screw  64  can be reached with a socket on a six-inch extension on a socket wrench, as shown in phantom at  76 . As a result, the lower pole piece  46  is adjustably supported by the lower guide plate  44  on the frame  12 , so that it can be positioned at different vertical locations relative to the upper guide plate  44  and also, separately, relative to the frame  12 . The lower pole piece  46  adjustment is set to the outlet of the dryer and is also changed when the material thickness of the ends  48  changes. 
     Because the inlet end  18  of the separator  10  is connected with the dryer when the separator is in use, it might not be feasible to view the position of the back end portion of the lower pole piece  46 . In accordance with one aspect of the invention, the lower guide plate  44  has at least one view port  80  for enabling viewing of the lower pole piece  46 , thereby to accurately adjust the position of the lower pole piece, which determines the strength of the magnetic field on the workpieces  48 . 
     The view port  80  is located in the second side wall  52  of the lower guide plate  44  and is shown in  FIGS. 5 and 7 . The view port  80  is an opening formed in the material of the second side wall  52  of the lower guide plate  44 . The opening  80  is located near the top of the second side wall  52  of the lower guide plate  44 . The opening  80  has an oval configuration with an upright long axis. Suitable view ports  80  could have different shapes than the one illustrated. The height of the opening  80  is selected to enable viewing, through the opening, of the lower pole piece  46 , at any point within the range of adjustment of the lower pole piece relative to the lower guide plate  44 . 
     The view port  80  is located near the inlet end, or back end, of the lower guide plate  44 . The lower pole piece  46  is located inside the M-shaped lower guide channel  44 . As a result, the view port  80  enables viewing of the vertical position of the back end of the lower pole piece  46 . The presence of the view port  80  thereby enables accurate adjustment of the position of the lower pole piece  46 , which determines strength of the magnetic field on the workpieces  48 . 
     The upper guide plate  40  is similar in configuration to the lower guide plate  44 , but reversed in orientation. The upper guide plate  40  thus has a generally W-shaped cross-sectional configuration, as best seen in  FIGS. 3 and 4 , including first and second side walls  82  and  84  that are interconnected by a V-shaped lower end wall  86 . The upper guide plate  40  has an intermediate portion  81  has portions that extend between an inlet end portion  83  and an outlet end portion  85  of the upper guide plate. The inlet end portion  83  of the upper guide plate  40  extends transverse to the intermediate portion  81  of the upper guide plate, as described below. 
     Two bolts  88  secure the outlet end  85  of the upper guide plate  40  to the sub-frame  34  (only one bolt  88  may be needed, on one side only). A releasable mechanism  92  supports the inlet end  83  of the upper guide plate  40  on the sub-frame  34 . Specifically, at the inlet end  83  of the upper guide plate  44 , two L-shaped slots  96  on the side walls  82  and  84  receive pins or screws  98  that stick out from the sub-frame  34 . The engagement of the pins  98  in the slots  96  supports the inlet end  83  of the upper guide plate  40  on the sub-frame  34 . 
     A pair of first mounting brackets  100  adjustably connect the sub-frame  34  with the front uprights  16 . In a similar manner, a pair of second mounting brackets  102  adjustably connect the sub-frame  34  with the back uprights  14 . Each one of the mounting brackets  100  and  102  has a fastener opening  108  that receives a fastener in the form of a bolt  110 . The bolts  110  have portions that are received in the slots  22  in the front and back uprights  16  and  14  of the frame  12 . 
     The four bolts  110  may be loosened or tightened to releasably secure the uprights  14  and  16  at different locations along the length of the uprights. When the four bolts  110  are loosened, the upper guide plate  40  and the sub-frame  34  are adjustable on the frame  12  so that they can be positioned at different vertical locations along the uprights  14  and  16 . When the four bolts  10  are tightened, the upper guide plate  40  is fixed in position on the frame  12 . Because the adjustment bolts  110  are provided at both the inlet end  83  and the outlet end  85  of the upper guide plate  40 , the two ends of the upper guide plate can be set at different vertical positions along the uprights  14  and  16 , to tilt the upper guide plate relative to horizontal, as is sometimes desired. 
     In accordance with another aspect of the invention, the separator  10  includes an adjustment mechanism  120  by which the position of the upper guide plate  40  is easily adjustable from above the separator, once the four bolts  110  are loosened. The adjustment mechanism  120  includes an adjusting screw or jack screw  122 . The jack screw  122  extends vertically through an opening  124  in the cross bar  32  in the sub-frame  30 . The jack screw  122  is threadedly received in a collar  126  in the opening  124 . As a result, rotation of the jack screw  122  about its axis causes the screw to move vertically relative to the frame  12  of the separator  10 . A handle  128  is located on the upper end of the jack screw  122 . A lock nut  130  is located on the jack screw  122  adjacent the collar  126 . 
     The lower end of the jack screw  122  is rotatably captured in a collar  132  fixed in the sub-frame  34  fixed for movement with the upper guide plate  40 . As a result, vertical movement of the jack screw  122  results in vertically directed force being applied to the upper guide plate  40 . 
     When the operator desires to adjust the vertical position of the upper guide plate  40 , the operator loosens the four adjusting bolts  110  and also loosens the lock nut  130 . The operator turns the handle  128 , causing the jack screw  122  to rotate relative to the frame  12 . Rotation of the jack screw  122  acts to draw the sub-frame  34  and thus the upper guide plate  40  upward or downward as desired. When the desired position of the upper guide plate  40  is reached, the lock nut  130  and the four adjusting bolts  110  are tightened to fix the upper guide plate in position on the frame  12 . 
     Another manner of adjustment of the upper guide plate  40  is possible. Specifically, the four adjusting bolts  110  can be configured and set to allow them to hold the upper guide plate  40  in position when in use, but allow it to slide along the uprights  14  and  16  when sufficient vertical force is applied. If that is done, then the adjusting bolts  110  do not need to be loosened before the handle  128  is turned. Simply turning the handle  128 , alone, can provide enough force to move the upper guide plate  40  vertically along the uprights  14  and  16 . 
     In accordance with a further aspect of the invention, the configuration of the upper guide plate  40  is adapted to guide any workpieces  48  that might be out of position in the stick, at the inlet end  18  of the separator  10 . Specifically, as can be seen in  FIGS. 2 and 6 , outer side portions of the lower end wall  86  of the upper guide plate  40 , at the inlet end  83  of the upper guide plate, are removed. The remaining central portion of the inlet end  83  of the upper guide plate  40  is split and is turned upward as two tabs  140 . The tabs  140  face backward (that is toward the dryer to which the separator  10  is connected) and downward. In addition, the side walls  82  and  84  of the upper guide plate  40  are cut away as shown at  142 , to provide clearance. 
     The inlet end portion  83  of the upper guide plate  40  thus is flared upward to form a funnel at the inlet end  18  of the separator  10 . The inlet opening  45  of the passage  41  is thus substantially larger in cross-sectional area than the intermediate portion  43  of the passage. This funnel shape of the upper guide plate  40  can catch and redirect any out of position workpieces  48  into their proper position in the stick. This can help to prevent jams and otherwise ensure smooth operation of the separator  10 . 
     In accordance with another aspect of the invention, the upper guide plate  40  ( FIG. 2 ) is easily removable from the frame  12  of the separator  10 . The upper guide plate  40  is held in place on the sub-frame  34  with only the two bolts  88  and the two pins  98 . The engagement of the pins  98  in the slots  96  supports the inlet end  83  of the upper guide plate  40  on the sub-frame  34 . 
     To remove the upper guide plate  40  from the separator  10 , the two bolts  88  are first removed. Then, the upper guide plate  40  is slid longitudinally toward the outlet end  20  of the separator  10 , until the pins  98  can come out of the slots  96 , a distance which may be about one inch, for example. When the pins  98  come out of the slots  96 , the inlet end  83  of the upper guide plate  40  drops down. At that point, the upper guide plate  40  can easily be pulled longitudinally out of the separator  10 , in a direction toward the outlet end  20  of the separator  10 . The separator  10  does not have to be moved away from the dryer to accomplish this, nor do any other parts of the separator have to be removed first. 
     In accordance with yet another aspect of the invention, the vertical position of the upper pole piece  42  is easily adjustable from the top of the separator  10 . The upper pole piece  42  ( FIG. 4 ) includes a frame  150  that supports two permanent magnets  152 . The magnets  152  extend along the length of the separator  10 . The frame  150  is supported at each end on two adjustment screws  154  that are threaded in the upper guide plate  40 . The frame  150  and the adjustment screws  154  are thus supported on the upper guide plate  40  for movement with the upper guide plate. 
     The heads of the adjustment screws  154  are accessible from above the upper pole piece  42  and the upper guide plate  40 . The separator  10  includes an upper cover  156  that has removable plugs  158  fitted in openings  160  in the upper cover. When one of the plugs  160  is removed as shown in  FIG. 4 , the head of the associated adjustment screw  154  is accessible. The adjustment screw  154  can be reached with a socket on a six-inch extension on a socket wrench as shown in phantom at  162 . 
     Rotation of the adjustment screw  154  at one end of the upper pole piece  42  causes that end of the upper pole piece to move upward or downward, as desired, relative to the upper guide plate  40 . The vertical position of the upper pole piece  42  can thus be set separately from the vertical position of the upper guide plate  40 . Alternatively, the upper pole piece  42  can be set a particular distance away from the upper guide plate  40 , then moved vertically with the upper guide plate along the frame  12 . 
     As a result, the upper pole piece  42  is adjustably supported by the upper guide plate  40  on the frame  12 , so that it can be positioned at different vertical locations relative to the frame  12  and also, separately, relative to the upper guide plate.