Abstract:
An apparatus for coating sheet metal strip substrate with lubricant type laminate includes top and bottom roller coaters for pinching the metal therebetween. Each roller coater includes an applicator roll supported between three contact points provided by two support rolls and the sheet metal surface itself. As such the applicator roll can be without and axle and freely removable. The applicator roll is driven by the movement of the metal strip. The roller coaters are movable between engaged and disengaged positions. When in the disengaged position, support brackets on the top roller coater prevent the applicator roll from dropping and replace the bottom support of the sheet metal. Pneumatic cylinders for actuating the top and bottom roller coaters are operatively connected such that the top and bottom roller coaters can “float” or move vertically while at the same time pinching the metal strip therebetween. One of the support rolls also acts as a lubricant transfer roll to transfer lubricant from a plurality of dispensing heads to the applicator roll. The dispensing heads include a cylindrically shaped recess surface receiving the transfer roll and a longitudinal outlet slot thereon for supplying lubricant to the transfer roll. The cylindrically shaped recess surface is spring loaded against the transfer roll. A manifold connects the dispensing heads to a electrically actuated solenoid valve. An electronic controller selectively modulates the solenoid valve to set an application rate for lubricant.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to roller coater type apparatus which are used to apply laminate to a substrate, and more particularly to a roller coater for coating one or both sides of a sheet metal strip fed along a predetermined path, such as for example into a press. 
     BACKGROUND OF THE INVENTION 
     In the metal forming industry, apparatus commonly known as roller coaters are used to apply a lubricant type laminate to sheet metal strip substrate. The lubricant laminated sheet metal is then typically fed into a press which punches and forms the sheet metal into patterns as desired. The lubricant performs the desirable function of lubricating the tooling of the press when it is working the metal. Sometimes it is desirable to switch the type of lubricant depending upon the particular types of operations being performed to the metal. It is usually desirable to coat both sides of the sheet metal strip with lubricant although it is occasionally desirable to coat only one side of sheet. It may also be desirable to change the width of the laminate application depending upon the width of the metal strip or the operations of the downstream press. 
     In the sheet metal lubrication industry, the typical roller coater apparatus includes upper and lower roller coater assemblies for application of lubricant to both sides of the sheet metal substrate. The upper and lower roller coaters include respective applicator rolls which pinch the sheet metal strip therebetween to apply lubrication to the top and bottom sides of the sheet metal strip. The applicator rolls are journalled in bearings at their ends for rotation about parallel rotational axes. 
     Heretofore, prior roller coater apparatus have had several drawbacks. One drawback is that there is typically a substantial amount of downtime and labor required when changing applicator rolls to apply different types of laminate. Another drawback is that roller coaters have less than desirable lubricant application that is either non-uniform or uneven, particularly where a small application rate is desired. This often results in wasted lubricant or alternatively a poorly lubricated press. Yet another drawback is that roller coater apparatus have not been able to adapt to changes in feed of the sheet metal strip. 
     SUMMARY OF THE INVENTION 
     It is therefore the general objective of the present invention to provide a more practical and reliable roller coater apparatus that is well suited to apply lubricant to sheet metal strip. 
     According to certain aspects of the present invention, it is an object to provide a roller coater apparatus that applies a more controlled amount of lubricant on sheet metal strip. 
     According to another aspect of the present invention, it is an object of the present invention to provide a roller coater apparatus that allows operators to easily change an applicator roll with a replacement roll or a different type of roll. 
     According to yet another aspect of the present invention, it is an object of the present invention to provide a roller coater apparatus that better accommodates vertical height fluctuations in the sheet metal strip during operation. 
     Accordingly, the present invention is directed in part towards a novel support arrangement for the applicator roll of a roller coater apparatus which is used to apply lubricant or other laminate to metal strip. The apparatus generally includes top and bottom roller coaters which are adapted to pinch metal strip there between in an engaged position. The support of the applicator roll is accomplished by three contact points arranged in a triangular configuration such that the applicator roll may be carried without the need for a physical connection between the applicator roll and the roller coater apparatus. The first contact point is provided by the metal strip itself A pair of supports such as support rolls or bearing rollers provide the second and third contact points and allow the applicator roll to rotate between the three contact points to apply lubricant to the metal strip. 
     The present invention is also directed towards the provision of a novel lubricant applicator assembly which generally comprises a transfer roll and a dispensing head. The transfer roll contacts the applicator roll along a laminate transfer line generally parallel with the rotational axis of the applicator roll. The dispensing head has a recessed surface which closely receives the outer cylindrical surface of the transfer roll. The dispensing head includes a longitudinal outlet in the recessed surface which receives laminate and applies laminate to the transfer roll, which in turn applies laminate to the applicator roll. 
     The present invention is also directed in part towards the provision of pneumatic vertical floatation of the top and bottom roller coater assemblies of a roller coater apparatus. According to this aspect, the roller coater apparatus includes top and bottom roller coater assemblies which are adapted to pinch metal strip there between to selectively coat one or both sides of the metal strip with lubricant. A pneumatic cylinder assembly is provided that is capable of moving upward and downward along with variations with the vertical type of the flow of the metal strip. To accomplish this, at least one pneumatic cylinder assembly is provided that includes a top and a bottom pneumatic cylinder. The top pneumatic cylinder operates the upper roller coater assembly while the bottom pneumatic cylinder operates the lower roller coater assembly. The compartments of the top and bottom cylinders are operatively connected in order to allow the cylinders to move upward and downward in unison without changing the pinching force applied to the sheet metal strip there between. 
     The present invention is also directed towards an improved control system for controlling the rate at which lubricant is applied to sheet metal strip. According to this aspect, a lubricant supply assembly generally includes a control valve, a manifold connecting the output flow of the control valve to at least one head in the roller coater, and means for modulating the valve between at least two different flow regulating positions to set an application rate of the laminate or lubricant. The modulating means may take the form of an electronic controller that is controllable to change the application rate if so desired. 
     Other object and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevation view of a roller coater apparatus for applying laminate to sheet metal strip, illustrated in a disengaged position. 
     FIG. 2 is a cross-section of the roller coater apparatus of FIG. 1 taken about line  2 — 2 , with hidden lines indicating how the applicator roll is removed. 
     FIG. 3 is a cross-section of the roller coater apparatus of FIG. 1 taken about line  3 — 3  illustrating the plumbing of the pneumatic cylinder assembly (partially shown in schematic). 
     FIG. 4 is a side elevation view of the roller coater apparatus of FIG. 1, shown in partial schematic form, illustrating the lubricant supply assembly in greater detail. 
     FIG. 5 is a side view of an applicator head used in the roller coater  10  apparatus of FIG.  1 . 
     FIG. 6 is a front view of the applicator head shown in FIG.  5 . 
     FIGS. 7 a  and  7   b  are cross sections of the applicator head shown in FIG. 5 taken about lines  7   a — 7   a  and  7   b — 7   b , respectively. 
     FIG. 8 is a top plan view of the roller coater apparatus illustrated in FIG.  1 . 
     FIG. 9 is a perspective view of certain working parts of the roller coater apparatus shown in FIG. 1, illustrated in an engaged position. 
     FIG. 10 is a cross section of certain parts of a roller coater of the roller coater apparatus illustrated in FIG.  1 . 
     FIG. 11 is a perspective view of certain working parts of a roller coater apparatus according to an alternative embodiment of the present invention. 
     While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1,  2  and  9 , a roller coater apparatus  20  for applying laminate to sheet metal is illustrated in accordance with a preferred embodiment of the present invention. The roller coater apparatus  20  is adapted to coat one or both sides of sheet metal strip material  21  with a liquid laminate, such as lubricant. The apparatus  20  is preferably positioned upstream of a press (not shown) that forms metal into desired shapes in mass production operations. With this arrangement, the lubricant on the sheet metal strip material  21  lubricates the movable tools (not shown) of the press to ensure sharper cutting tools and a longer lifespan for the tools. 
     To facilitate coating of both sides of the metal strip material  21 , the apparatus  20  preferably includes top and bottom roller coater assemblies  22 ,  24  (designated as such for ease of understanding because the top roller coater assembly  22  is typically vertically above the bottom roller coater assembly  24 ). The roller coater assemblies  22 ,  24  are carried on a stationary support frame  26  and have generally cylindrical applicator rolls  30  that are adapted to pinch the metal strip material therebetween for application of lubricant to top and bottom sides of the metal strip material  21 . During operation, the metal strip material  21  is advanced through the roller coater apparatus  20  towards the press by a feed apparatus that is typically separate from the coater apparatus  20 . The advancing movement of the metal strip material  21  drives each of the applicator rolls  30  about an axis of rotation. The rotation of the applicator rolls  30  causes them to receive a controlled amount of lubricant across their surface from a lubricant applicator assembly  34 . After receiving the controlled amount of lubricant, the applicator rolls  30  subsequently coat the lubricant across the entire or selected surface areas of the metal strip material  21 . 
     Each roller coater assembly  22 ,  24  also includes a support carriage  28  carried by the frame  26  for linear movement relative thereto. The carriages  28  are mounted between a pair of pneumatic cylinder assemblies  32  which position the carriages  28  relative to each other. In particular, the pneumatic cylinder assemblies  32  are operable to move the roller coater assemblies  22 ,  24  closely together or far apart between engaged and disengaged positions, as illustrated with a comparison of FIGS. 1 and 9. In the engaged position, the applicator rolls  28  pinch the metal strip material  21  therebetween for application of lubricant. In the disengaged position, the applicator rolls  28  are spaced vertically apart from each other to facilitate service maintenance and/or loading of new stock material to the roller coater. 
     It is an aspect of the present invention that the applicator rolls are carried between three contact points while in the engaged position, such that a mechanical connection between the applicator roll  30  and the support carriage  28  is not necessary. To provide two of the contact points, a pair of supports which take the form of a bearing roller  36  and a transfer roll  38  are provided for each of the respective top and bottom roller coater assemblies  22 ,  24 . However, other supports and support combinations may also be used such as two support rolls as shown in alternative embodiment of FIG. 11, and/or other similar such support means as a low friction skid support surface. It should be noted that supports which rotate with the applicator rolls are preferred for durability and reliability reasons. In either event, the preferred embodiment of each support includes a stationary support shaft  41  mounted to the support structure  39  of the carriage  28  and ball or roller bearings  43  for facilitating rotation of the roll followers. The rotational axes of the bearing roller  36  and transfer roll  38  are generally parallel with the rotational axis of the applicator roll  30 . In the top roller coater assembly  22  the support rolls bearing roller  36  and transfer roll  38  provide support to the top side of the applicator roll  30 . In the bottom roller coater assembly  24 , the reverse is true, namely, the bearing roller  36  and transfer roll  38  provide support to the bottom side of the applicator roll  30 . The bearing roller  36  and transfer roll  38  are preferably made of rigid material such as steel to facilitate proper alignment of the respective applicator rolls  30  of the top and bottom roller coater assemblies  22 ,  24 . 
     The bearing roller  36  and transfer roll  38  provide two contact points for support of the applicator roll  30 . When the roller coater assemblies  22 ,  24  are in the engaged position, the sheet metal strip material  21  provides the third contact point, and the pinching force between the top and bottom roller coater assemblies  22 ,  24  maintains the applicator rolls  30  against the bearing roller  36  and transfer roll  38 . When the roller coater assemblies  22 ,  24  are moved apart from each other to the disengaged position, the support provided by the sheet metal strip material  21  ceases to exist. In the bottom roller coater assembly  24 , this is of little significance as gravity maintains the applicator roll  30  against the bearing roller  36  and transfer roll  38  for support. However, in the top roller coater assembly  22 , gravity causes the applicator roll  30  drop downward away from the bearing roller  36  and transfer roll  38 . As such, the preferred embodiment includes means for supporting the upper applicator roll  30  in the disengaged position, which takes the form of two support arms  42  on the top roller coater assembly  22 . The support arms  42  include beveled or cylindrical contact surfaces  44  that provide two contact points to support the bottom side of the applicator roll. The contact surfaces  44  are located in close proximity to the outer peripheral surface of the applicator roll  30  while in the engaged position such that the applicator roll moves downward only slightly when the top roller coater assembly moves into the disengaged position. Alternatively, the arms  42  could carry small rolls or rollers if desired to provide the contact points which could also continuously contact the applicator rolls. In the preferred embodiment, the support arms  42  are connected to the support structure  39  of the upper carriage  28 , and selectively held in position by a pair of manually operable spring loaded locking mechanisms  47  mounted to the support structure at opposing ends of the roller coater  22 . 
     At least one of the arms  42  is movable between supporting and nonsupporting positions to facilitate removal of the applicator roll  30  if desired. As shown in FIG. 2, one of the arms  42  is pivotably connected to the carriage  28  and is capable of being locked in a conventional manner in the supporting position for support of the applicator roll  30 . It is an advantage that facilitates easy changing of applicator rolls  30 . Applicator rolls may be changed when worn or damaged or alternatively when switching between two different types of lubricant, or other maintenance reason. Little labor and effort is necessary to change the applicator roll as the applicator roll  30  drops down once the support arm  42  is moved to the non-supporting position. It should be noted that the applicator roll  30  of the bottom roller coater assembly  30  may be easily lifted off the bearing roller  36  and transfer roll  38  to facilitate changing of the applicator roll  30 . It is an advantage that the applicator rolls  30  do not need an axle journalled in bearings for support or location. 
     Greater detail of a preferred embodiment of the applicator roll  30 , the supports in the form of a bearing roller  36  and transfer roll  38 , the support arm  42  and locking mechanism  47  are illustrated in the partial fragmentary cross section of FIG.  10 . As illustrated in FIG. 10, the applicator roll  30  includes a metal cylindrical drum  51 , a felt transfer liner  53 , a pair of end caps  55  enclosing the ends of the drum  51  and a pair of collars  57  that secure the liner  53  to the drum  51 . The collars  57  in combination with the end caps  55  define cylindrical recesses  59  which provide a riding surface for the bearing roller  36 . The collars  57  also provide beveled surfaces  61  which act as mechanical stops for axial retention of the applicator roll  30 . 
     It is another aspect of the present invention, that the pneumatic cylinder assemblies  32  are operatively configured to allow the top and bottom roller coater assemblies  22 ,  24  to “float” or move vertically upwards or downwards in unison with the feed or flow of the sheet metal strip material  21 . For lighter metal strip material the cylinders may also be supported in central position by a vertically adjustable shelf or support bar (not shown). Referring to FIGS. 1,  3  and  8 , the pneumatic cylinder assemblies  32  generally include top and bottom pneumatic cylinders  46 ,  48  and a pneumatic control  50  operatively connected to the cylinders  46 ,  48  for selectively pressurizing or exhausting the pneumatic cylinders  46 ,  48  to move the support carriages  28  between engaged and disengaged positions. In the preferred embodiment, the pneumatic control  50  comprises a manually operated four-way valve  49  (two three-way valves) pneumatically connected to a compressed air supply  65  (which receives compressed air from a compressor and conditions the air appropriately) and connected to a manual control  69  for control thereby. Each of the pneumatic cylinders  46 ,  48  includes a cylinder housing  52  and a piston actuator  54 . The housing  52  defines a cylindrical control chamber in which the piston actuator  54  is slidably mounted to facilitate linear translation between the piston actuator  54  and the housing  52 . 
     The piston actuators  54  divide each of their corresponding control chambers into top and bottom pressure compartments  58 ,  60 . In the preferred embodiment, the piston actuators  54  are secured to the frame  26  by a central vertical support shaft  62  extending through both top and bottom cylinders  46 ,  48 . The housings  52  are fastened or pinned to the support structures  39  of the carriages  28  such that the cylinder housings  52  are movable relative to the frame  26  while the piston actuators  54  are stationary relative to the frame  26 . However, it will be appreciated to one skilled in the art that the reverse could be true with the pistons secured to the carriages and the cylinder housings secured to the frame. 
     In the engaged position, the bottom compartments  60  of the top cylinders  46  and the top compartments  58  of the bottom cylinders  48  are pressurized to cause the roller coater assemblies  22 ,  24  to be biased towards one another and thereby pinch the sheet metal strip material  21  therebetween. While in the engaged position, the pneumatic actuator assemblies  32  are configured to allow the top and bottom roller coater assemblies  22 ,  24  to float in unison vertically upward and downward. To achieve this floatation, the top compartment  58  of each top cylinder  46  is connected by a first conduit  64  to the bottom compartment  60  of the corresponding bottom cylinder  48 , and the bottom pressure compartment  60  of each top cylinder  46  is connected by a second conduit  66  to the top compartment  58  of the corresponding bottom cylinder  48  (See FIG.  3 ). As indicated in the preferred embodiment, the conduits  64 ,  66  are preferably provided entirely or partially by internal passages in the support shaft  62 , or alternatively external hoses or pipes. It is an advantage that the internal passage of conduit  64  reduces the need for hoses on the apparatus  20 . 
     Turning now to other details of the preferred embodiment, and particularly the lubricant applicator assembly  34 , reference can be had to FIGS. 5-8. As illustrated, the lubricant applicator assembly  34  for each of the roller coater assemblies  22 ,  24  of the preferred embodiment generally includes at least one and preferably multiple dispensing heads  68  and the transfer roll  38  which as already indicated may also act as a support for the applicator roll  30 . In operation, the feed of the sheet metal strip  31  drives the applicator roll  30  which in turn rotates the transfer roll  38  and thereby causes the transfer of lubricant from the heads  68  to the applicator roll  30 . 
     The dispensing heads  68  include an elongate concave recessed surface  70  that is preferably cylindrical such that is closely receives the cylindrical outer periphery of the transfer roll  38 . Each of the dispensing heads  68  includes an inlet port  72  for receiving lubricant from the hose  73  of a supply manifold  75 , and an elongate outlet  74  that extends across the axial length of the transfer roll  38  for application of lubricant to the transfer roll  38 . In the preferred embodiment, the outlet  74  takes the form of a continuous channel  76  formed in the head  68 . However, it will be appreciated that multiple spaced apart holes arranged closely together along an axial length may also be used to provide the outlet  74 . The outlet  74  is preferably configured to apply a uniform line of lubricant over the transfer roll  38 . 
     As indicated in FIGS. 5 and 7 a , pins  80  are used to mount each dispensing head  68  on a support bracket in the form of an elongate support bar  78 . The pins  80  slidably engage the head  68  to permit linear translation between each head  68  and the transfer roll  30 . At least one spring  81  or other similar resilient mechanism is located between the support bar  78  and the head  68  to serve as means for urging the head  68  against the transfer roll  38  with the recess  70  seated against the outer surface thereof. In the preferred embodiment the head includes a sealed flow passageway  82  from the hose  73  to the outlet channel  76 . The head  68  includes an inlet port  72  connected to the hose  73  by a suitable fitting  79  for reception of lubricant. To ensure relatively even lubricant distribution and pressure in the channel  76 , multiple ports  84  are provided to connect the outlet channel  76  to an elongate lubricant collection chamber  86  inside the head  68 . 
     Referring to FIGS. 1,  4  and  8 , the roller coater apparatus  20  also includes a lubricant supply assembly  88  to feed and supply the dispensing heads  68  with lubricant. The lubricant supply assembly  88  is fed externally from either an air pressurized pressure pot  87  or fixed displacement (or variable displacement) pump  89 , such as a piston pump, or both. The pump  89  or pressure pot  87  generally drive lubricant from a supply reservoir  90  into the inlet  77  of the lubricant supply assembly  88 . The lubricant supply assembly  88  generally includes a control valve in the form of an electrically actuated solenoid valve  94 , multiple on/off control valves  94 , one for each dispensing head  68 , and upper and lower supply manifolds  75  that include a hose  73  for each dispensing head  68 . The on/off control valves  96  are manually operable and turn on or shut off flow to each of the dispensing heads  68 . The control valves  96  are located in upper and lower sets in convenient locations for the upper and lower manifolds  75 . 
     It is an aspect of the present invention, that an electronic controller modulates the electrically actuated solenoid valve  94  between different flow regulating positions at a selected frequency to set an application rate for lubricant application. It has been found that the modulating action along with the novel lubricant applicator assembly  34  provide a more uniform resulting application to the sheet metal strip  21 . The modulating frequency depends upon the desired application rate to the sheet metal strip. In the preferred embodiment, fully open and closed position correspond to the two regulating positions of the solenoid valve  94 , although partially open and closed positions may also be used. The electronic controller  67  can recall different application rates and can also compensate for the number of on/off valves that are open and closed. An optional restriction orifice  98  may also be provided upstream of the inlet port  77  for controlling the maximum amount of lubricant flow to the solenoid valve  94 .