Patent Publication Number: US-10322894-B2

Title: Cleanable sheet feeder

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
     This application is a non-provisional application of Application No. 62/492,536, filed May 1, 2017 and claims priority from that application which is also deemed incorporated by reference in its entirety in this application. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR. DEVELOPMENT 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     The present invention relates generally to an apparatus for feeding sheet-like articles, one at a time, from the bottom of a stack of such articles and, more particularly, to a sheet feeder especially designed for use in the food, pharmaceutical and medical products industries. The design, construction, and materials must comply with applicable industry and regulatory standards and facilitate effective cleaning and disinfection of the sheet feeder by a variety of methods without harm to the equipment. 
     II. Discussion of the Prior Art 
     Over the past twenty years, applicant&#39;s assignee, Multifeeder Technology, Inc., of White year, Minnesota, has been manufacturing and selling sheet feeding equipment of the type generally described in the Vedoy et. al U.S. Pat. Nos. 6,050,563 and 7,040,613, the contents of these two patents are hereby incorporated by reference as if set forth in full Machines constructed as described therein have been widely used to feed, one at a time, from a stack of flat articles, such as printed materials, card stock, compact disks, pharmaceutical blister packs and the like at high speeds. However, due to their construction, they failed to meet FDA and other applicable standards for use in the food and other industries where pathogens must be addressed. These standards dictate cleaning and disinfection outcomes for equipment exposed to organic materials, such as food products for human and animal consumption. If the equipment is to be cleaned and disinfected, it necessarily must be taken off-line, which adversely impacts product production, especially if it is to be subjected to pressure washing, washing, and rinsing operations that are needed to remove soilage and pathogens. 
     In the following discussion of the prior art machine described in the aforereferenced Vedoy patents, the reference numerals are those found in the Vedoy patents referenced above. 
     To meet the applicable standards and requirements, applicants have redesigned the earlier sheet feeding machines in a way to facilitate effective cleaning and disinfection and comply with above referenced standards. For example, the stripper wheel shaft  54  seen in FIG. 9 of the &#39;563 patent has been redesigned as a single, one-piece, roller, thereby eliminating the need for plural rollers  52  and their joints and crevices which make the earlier machine difficult to clean. Likewise, the feed belt drive shaft  42  of the earlier machine is replaced with a one-piece, multi-crown shaft, again eliminating the need for plural drive rollers  40 . 
     In the design of the present invention, flexible, accordion-pleated, bellows-type gaskets in conjunction with bearing isolators are made to surround the openings in the housings  12 ,  14  where the ends of the input drive shaft, input idler shaft, the stripper shaft and the upper and lower discharge shafts enter the housings to prevent entry of cleaning solutions into the housings while still allowing tension adjustments of the infeed belts and vertical spacing adjustment of the stripper shaft and upper discharge drive shaft relative to the infeed drive shaft and lower discharge drive shaft. 
     In the design of the present invention, the entire discharge conveyor assembly is of a unitary construction allowing it to be cleaned in place or readily removed in a matter of a minute or two from the remainder of the sheet feeder, allowing it to be cleaned in a dipping or submersion mode. 
     The housings  12 ,  14  of the earlier machine of the &#39;563 patent are now made of stainless steel. The new housing covers of the present invention incorporate a formed in-place internal gasket and mate with the remainder of the box-like enclosures to block entry of cleaning liquids into the interior of the housings. Also, on the new design of the present invention, a moisture-tight, clear polymer hinged cover is made to shield the keypad and display from exposure to moisture when closed atop the housing. 
     Further modifications of the older sheet feeder of the &#39;563 patent to render it useful in the food, pharmaceutical and medical products industries will be further explained below. To the best of applicant&#39;s belief, the present invention constitutes the first and only hygienic sheet feeder currently commercially available for use in the food processing and packaging industry. 
     SUMMARY OF THE INVENTION 
     It is believed that the sheet feeder described in the following specification and illustrated in the drawings is the first friction feeder especially designed for use in the food industry. As an example, it can be made to deliver cardboard disks onto a conveyor, later topped with a frozen pizza and printed advertising material before entering a film wrapping machine. The new friction feeder can be cleaned in place on a factory floor and need not be removed from its normal work station in order to effect cleaning. Further, the electronic components for the sheet feeder are self-contained rather than stored separately in a cable connected module. The use of bellows-style seals at entry points where shafts enter the mechanical and electrical housings permits adjustment of the shaft&#39;s height and belt tensions to accommodate sheets of differing thicknesses while precluding entry of cleaning fluids into the housings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, especially when considered in conjunction with the accompanying drawings in which like numerals in the several views refer to corresponding parts: 
         FIG. 1  is a perspective view of the sheet feeder of the present invention when viewed from one side of the product discharge end; 
         FIG. 2  is a close-up of the machine of  FIG. 1  when viewed from one side of the product infeed end; 
         FIG. 3  is a close-up of the machine viewed from the product infeed end with the infeed hopper removed to better illustrate the infeed belts and stripper shafts; 
         FIG. 3A  is a partial cross-section view taken through the bearings and gap height adjustment mechanism in the area of item  54  in  FIG. 3 ; 
         FIG. 3B  is a partial cross-section view showing the mechanism for adjustment of the belt tension of the infeed belts in the area of item  48  in  FIG. 3 ; 
         FIG. 3C  is a partial left side elevation view of the preferred embodiment with the left side housing removed; 
         FIG. 3D  is a partial right side elevation view of the preferred embodiment with the right side housing removed; 
         FIG. 4  is a perspective view of the infeed hopper removed from the sheet feeder; 
         FIG. 5  is a detailed perspective view of the sheet feeder&#39;s discharge assembly removed from the rest of the sheet feeder and with the discharge belts removed; 
         FIG. 6  is a partial view of the discharge assembly showing the shaft attachment in cross-section; 
         FIG. 7  is a partial bottom view of the preferred embodiment; 
         FIG. 8  is a further partial bottom view showing the infeed shaft and bellows style gasket employed with it. Also shown is one of the cross members and it&#39;s gasket seal; 
         FIG. 9  shows the electronics housing with a keypad and display viewable beneath a water-tight clear polymer hinged cover; 
         FIG. 10  is a close-up partial view of the junction between the mechanical housing and the upper discharge shaft and the on stripper shaft; 
         FIG. 11  is a sectioned view taken through the infeed drive shaft, the infeed idler shaft and the lower discharge shaft; and 
         FIG. 12  is a cross-section view taken through a cross bar connecting the housings to one another. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     This description of the preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top” and “bottom” as well as derivatives thereof (e.g., “horizontally”, “downwardly”, “upwardly”, etc.) should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “connected”, “connecting”, “attached”, “attaching”, “join” and “joining” are used interchangeably and refer to one structure or surface being secured to another structure or surface or integrally fabricated in one piece, unless expressively described otherwise. 
     In many respects, the sheet feeder of the present invention constitutes a modification of the sheet feeders described in the Vedoy et al Patents referenced above. It has been modified so as to comply with existing regulations for equipment that is intended to be exposed to food for humans and other animals. For example, under the provisions of 21 CFR 117.40, all plant equipment and utensils used in manufacturing, processing, packing or holding food must: 
     (1) Be designed and of such material and workmanship that they are adequately cleanable, and must be adequately maintained to protect against allergen cross-contact and contamination; 
     (2) Be designed, constructed and used appropriately to avoid the adulteration of food with lubricants, fuel, metal fragments, contaminated water or other contaminants; 
     (3) Be installed so as to facilitate cleaning and maintenance of the equipment and of adjacent spaces; 
     (4) Have food-contact surfaces that are corrosion-resistant when in contact with food; 
     (5) have food-contact surfaces made of non-toxic materials and designed to withstand the environment of their intended use and the action of food, and, if applicable, cleaning compounds, sterilizing agents, and cleaning procedures; and 
     (6) Be maintained so that food-contact surfaces are protected from allergen cross-contact and from being contaminated by any source, including unlawful indirect food additives. 
     Applicable regulations further include the requirement that any equipment in areas where food is manufactured, processed, packed or held that does not come into contact with the food must be so constructed that it can be kept in a clean and sanitary condition. Good manufacturing practices further require that the performance of filling, assembling, packaging and other operations be carried out so that food is protected against allergen cross-contact, contamination and growth of undesirable microorganisms. 
     In redesigning its sheet feeder for use in the food processing and related industries, the named inventor at Multifeeder Technology, Inc., has redesigned its sheet feeding equipment to comply with these applicable standards. The following specification describes certain of the measures taken to achieve the desired results that are not readily obvious from the applicable industry standards. 
     Referring to  FIGS. 1 and 2 , a preferred embodiment of a sheet feeder designed for use in the food industry is indicated generally by numeral  10 . It includes a base comprising a pair of box-like housings  12  and  14  held in parallel, spaced-apart relation by a three cross members, including item  16  shown in  FIG. 2  and item  102  shown in  FIGS. 7, 8 and 12 . The housing  12  contains the mechanical gearing and drive belts functionally similar to that shown in FIG. 4 of the &#39;563 patent referenced above, but here the housing  12  is fabricated from stainless steel rather than ordinary cold rolled steel, aluminum, or molded polymer. It has an open-top box portion  18  with a removable cover  20  held by separable hinges, as at  22 , and by hygienic cam locks as at  24 , purposely selected to avoid Allen wrench sockets in their heads which might otherwise be difficult to clean. A liquid impervious gasket  26  formed in place in the removable cover  20  serves to prevent ingress of moisture between the cover and a box portion during cleaning operations. 
     The housing member  14 , also of stainless steel, contains both mechanical gearing and drive belts, like that shown in FIG. 5 of the &#39;563 patent, as well as the electronic circuitry for controlling operation of the sheet feeder. The housing  14  meets NEMA and IP66 standards and includes a box-like receptacle  28  having a removable cover  30  similar in construction to the housing  12  and also includes a gasket seal  32  formed in place in the removable cover  30  Attached to the top of the receptacle  28  is a clear polymer cover  34  that is hinged at  36  allowing it to be lifted from its covering relation with respect to an underlying display panel  38  and a key pad  40 , like the display panel and key pad 94 of the Vedoy &#39;563 patent. The clear polymer cover  34  also has a peripherally located gasket  41  that seals to the box-like receptacle  28  when the cover is closed. 
     The upper and lower discharge belts  66  (see also  FIG. 10 ) are deployed about motor driven upper and lower discharge drive shafts  80  and  82  respectively (see also  FIG. 10 ). These shafts are each of a one-piece, multi-crown, undulating construction which avoids the use of multiple pulleys on shafts that were used in the earlier Vedoy &#39;563 patent. In this way, there are no joints and crevices along the shafts that would otherwise make it more difficult and time consuming to sanitize. 
     Referring to  FIG. 3 , which shows a partial view of the sheet feeder  10  with its infeed hopper removed, the infeed belts  42  are deployed about a motor driven drive shaft  45  and an infeed idler shaft  44 , each of a one-piece, multi-crown, undulating construction which avoids the use of multiple pulleys on shafts like 40 and 42 of the Vedoy &#39;563 machine. In this way, there are no joints and crevices along the that would otherwise make it more difficult and time consuming to sanitize. Likewise, in the machine of the present invention, the stripper roller  46  is of a similar one-piece construction, thereby again eliminating the multiple pulleys on shafts, like 52 used in the Vedoy &#39;563 patent. 
     To better understand the drive mechanism for the endless feeder belts  36 ′, the upper and lower endless discharge belts  62 ′,  FIGS. 3C and 3D  respectively show a left side view and a right side view with the housings removed to reveal the working parts. As can be seen, the feed belt drive shaft  42 ′ passes through a circular opening in the housing wall and then through a similar hole in a bearing support plate  94 ′ that is affixed to the inside of the wall of the housing  14 . Secured to the free end of the feed belt drive shaft  42 ′ is a pulley  96 ′ that is adapted to be driven by a motor by way of a timing belt. 
     Referring next to  FIG. 3D , it can be seen that the shaft  42 ′ passes through a circular opening formed in the back wall of the housing  12  and through a hole formed in a right bearing support plate  97 ′ and that a timing belt pulley  98 ′ is affixed to the right end of the shaft  42 ′. The lower discharge belt shaft  68 ′ is journaled for rotation in bearings disposed in the right bearing support plate  97 ′ and a further timing belt pulley  100 ′ is affixed to the protruding end of the shaft  68 ′. A notched timing belt  102 ′ is deployed about the pulleys  98 ′ and  100 ′ so that rotation of the feed belt drive shaft  42 ′ by the motor also rotates the lower discharge output shaft  68 ′. The pulley  100 ′ is of a slightly smaller diameter than the pulley  98 ′ so that the discharge belt pulley  100 ′ moves about 12 percent faster than the infeed belt  36 ′. 
     Referring again to  FIG. 3C , the left end of the lower discharge belt shaft  68 ′ is journaled for rotation in the bearing support plate  94 ′ and has a spur gear  104 ′ keyed to it. The spur gear  104 ′ is arranged to mesh with a similar spur gear  106 ′ that is affixed to the left end of the upper discharge belt shaft  74 ′. Hence, the upper discharge shaft  74 ′ is made to turn at the same rotational speed as the lower discharge belt shaft  68 ′, causing the adjacent flights of the discharge belts  62 ′ and  60 ′ to move in the forward direction at the same linear speed. 
     The upper discharge shaft  74 ′ is journaled for rotation in a sliding bearing block  108 ′ that is fitted into a vertically oriented slot  110 ′ formed in the bearing support plate  94 ′. The sliding bearing block  108 ′ preferably has its side edges treated with Teflon® or other lubricious material so to be free to move up and down vertically within the slot  110 ′. It is normally urged in a downward direction by compression springs  112 ′ and  114 ′ operatively disposed between shoulders formed on the sliding bearing block  108 ′ and the upper edge of the slot  110 ′ in the bearing mounting plate  94 ′. 
     By providing elongated teeth on the spur gears  104 ′ and  106 ′, they continue to remain meshed even with upward displacement of the shaft  74 ′ against the force of the compression springs  112 ′ and  114 ′. 
     The stripper wheel shaft  54 ′ is also journaled for rotation in a sliding bearing block  116 ′ fitted into a vertically oriented slot  118 ′ in the bearing support plate  94 ′. Again, compression springs  120 ′ and  122 ′ normally urge the sliding bearing block  1116 ′ and the shaft  54 ′ downward toward the feed belt drive shaft  42 ′. 
     Returning again to  FIG. 3D , it shows the right ends of the stripper wheel shaft  54 ′ and the upper discharge shaft  74 ′, each being journaled for rotation in separate sliding bearing blocks  124 ′ and  126 ′, respectively. These sliding bearing blocks are again fitted into vertically oriented slots  128 ′ and  130 ′ in the bearing support plate and are preferably coated along their side edges with a lubricious material for facilitating low friction sliding contact between the bearing blocks and their associated slots. Compression springs, as at  132 ′,  134 ′  136 ′ and  138 ′, normally urge the sliding bearing blocks  124 ′ and  126 ′ toward the underlying shafts  42 ′ and  68 ′. 
     In order to be able to adjust the tension of the infeed belts  42  and the spacing (height) of the gap between the infeed belts  42  and the stripper roller  46  to accommodate sheet items of differing thicknesses in the manner described in column 7, line 9 through column 8, line 15, of the Vedoy &#39;563 patent and as also described in greater detail in the Vedoy &#39;613 patent, while still blocking entry of water or cleaning chemicals into the interior of the housings  12  and  14 , bellows gaskets  48 ,  50  ( FIGS. 3 and 3B ) incorporating bearing isolators, fit over apertures in the housings leading to the slidable bearing assemblies for the infeed idler shaft  44 . 
     Similar “double” bellows gaskets  52 ,  54  ( FIGS. 3 and 3A ) fit about housing apertures leading to the slidable bearings used to journal the stripper roller  46  and upper discharge drive shaft  80  ( FIGS. 1 and 3A ). 
       FIG. 3A  is a partial cross-section view taken through the bearings and gap height adjustment mechanism (in the area of item  54  in  FIG. 3 ) for setting the spacing between the infeed belts  42  on infeed shaft  45  and the stripper rollers  46 , and between the upper and lower discharge drive shafts  80  and  82  respectively. Seen clamped to a the back wall of the housing  14  by a clamping ring  51  and precision length shoulder screws  49  is the accordion-pleated, flexible, elastomeric double bellows member  54 . Vulcanized to its proximal end  53  are two stainless steel plates  55  in which are fitted bearing isolators  57  of a multi piece labyrinth design allowing the shaft to rotate while precluding entry of water or other cleaning fluid and also preventing the loss of bearing lubricants. 
     The plates  55  are joined to each of two slide blocks  59  by screws within precision length spacers  61  and  63 , respectively, four screws and spacers per plate. The screws within spacers extend through a slot formed through the housing wall  14 . The slide blocks  59  have combination radial-axial locating bearings  65  for journaling extensions  67  of the upper discharge drive shaft  80  and stripper shaft  46 . The slide blocks  59  have a vertically extending threaded bore  69  into which is inserted a lead screw  71  which, when turned, raises or lowers the stripper roller  46  and upper discharge drive shaft  80  relative to the infeed roller  45  for adjusting the height of the gaps there between. 
     The above adjusting mechanism is isolated from the (food or pharmaceutical) product area of the sheet feeder in a hygienic design by the first and second pairs of flexible elastomeric bellows incorporating molded in plate and bearing isolator. The bellows, plate and isolator are precisely aligned and connected to and move with the above first and second movable bearing blocks. All the items above referring to  FIG. 3A  together comprise a hygienic height adjustment mechanism. 
     The precision turned lower discharge shaft extension  73  is journaled for rotation in a combination radial-axial locating bearing  75  fitted into a stationary block  77  bolted to the inner wall of the housing  14  after passing through a further bearing isolator  79  and a tubular steel spacer  81  that is immovably affixed (welded) to the outer wall surface of the housing  14 . The infeed drive shaft  45  is driven from a toothed sprocket from the motor  86  seen in the bottom view of  FIG. 8  via a toothed belt (not shown) contained within the housing  12 . As seen in  FIGS. 3, 8 and 11 , the same type of shaft to housing sealing arrangement immovably affixed (welded) is employed on the opposed ends of the lower discharge drive shaft  82 . 
     Referring next to  FIG. 3B , shown is a cross-section through the infeed idler shaft  44  of  FIG. 2 . Again, to seal the assembly against entry of cleaning solutions which may be delivered via a pressure-washer source or other means, a flexible, elastomer bellow  48  is clamped to the outer surface of the back walls of housings  12  and  14  using clamp rings as at  87  and slot head precision length shoulder screws  89 , as illustrated. Again, the bellows  48  are vulcanized to a stainless steel plate  91  having a center bore  93  in which is fitted a commercially available bearing isolator of known construction having a labyrinth seal that functions to prevent entry of fluids into the cavity containing components including roller bearing  95  that journals the ends of the infeed shaft  44 . The roller bearings  95  are disposed within a slide block  97 . An adjustment lead screw  99  passes through a plate  101  fastened to the outer side of the back wall of the housing  14  and into a threaded bore  103  in the slide block  97  so that rotation of the lead screw  99  laterally displaces the slide block as well as the plate  91  and shaft  44  horizontally due to the screws within precision length spacers  105  connecting the two together to thereby loosen or tighten the belt tension of the infeed belts  42  ( FIG. 2 ). 
     The above adjusting mechanism is isolated from the (food or pharmaceutical) product area of the sheet feeder in a hygienic design by the third pair of flexible elastomeric bellows incorporating molded in plate and bearing isolator. The bellows, plate, and isolator are precisely aligned and connected to and move with the above third movable bearing blocks. All the items above referring to  FIG. 3B  together comprise a hygienic belt adjustment mechanism. 
     Referring next to  FIG. 4 , it shows the sheet infeed hopper  13  of  FIGS. 1 and 2  removed from the sheet feeder&#39;s base. It is designed to allow it to be readily removed from the base to be cleaned in a dipping or emersion-type cleaning operation. It optionally can be cleaned in place with minimal disassembly of removing guide rods  15 . The vertical sheet guide rods  15  have an arcuate contour at their lower ends to closely conform to and straddle the stripper roller  46 , as shown in  FIG. 2 , when the hopper assembly is bolted to the rear surface of the housings  12  and  14  by two bolts  17 , one per side, as seen in  FIG. 10 . Removal of just two bolts  17  allows quick release of the hopper assembly as a unit from the sheet feeder base. 
       FIG. 5  is a detailed, perspective view of the sheet feeder&#39;s discharge assembly with the discharge belts absent to better show the constructional details. It is indicated generally by numeral  56  and seen to comprise a pair of parallel stainless steel side plates  58  and  60  with a plurality of stationary cylindrical rods  62  held in parallel alignment with one another along the length dimension of the discharge assembly  56 . Flat, toroidal seals  63  surround the stationary rods  62  at their points of entry of the plates  58 ,  60 , as best seen in  FIG. 6 . The fasteners used to retain the rods  62  are also sealed with toroidal seals of the same type as  63 . Mounted for rotation on the plurality of rods  62  are belt spools  64  over which a set of endless belts  66  ( FIG. 3 ) are strung leading to nose rollers  68  and  70 . Again, the spacing between these two nose rollers is adjustable by means of the Vernier adjustment screws  72  and  74  fitted into threaded retainers on the ends of the upper nose roller  68 . Mounting rings  76  and  78  are bolted to the side rails  58 ,  60  and are designed to surround the tubular steel spacer  81  ( FIGS. 3A and 11 ). In this way, the discharge assembly can also be readily removed from the remainder of the sheet feeder as a unit, allowing it to be cleaned separately from the rest of the sheet feeder it optionally can be cleaned in place with minimal disassembly of removing the upper discharge sub-assembly for separate cleaning. The discharge belts  66  ride over the spools  64  and a sufficient clearance is provided between the shafts and the ID of the spools to permit effective entry of cleaning fluid to flush out any microorganisms. The spools are also easily moved axially on the shafts to facilitate cleaning of the entire shaft surfaces. 
     Referring to  FIG. 8 , the motor for driving the infeed conveyor, the discharge conveyor and the stripper rollers is identified by numeral  86 . Also shown is crossbar  102  and seal  101  used for precision alignment of mechanisms contained in housings  12  and  14  of  FIGS. 1, 2, and 3 . The gearing and drive belts involved are contained within the housings  12  and  14  and are more particularly described in the Vedoy &#39;563 patent. 
     As seen in  FIG. 10 , the upper discharge shaft  80  has a bellows-type seal arrangement  107  clamped to the rear panels of housings  12  and  14  surrounding the entry points of the shaft  80  into the housings. The seal arrangement for the mechanism for adjusting the spacing between the upper and lower discharge shafts is quite similar to that used on the stripper shaft  46  and its description need not be repeated here. 
       FIG. 12  is a cross section cut through the cross bar  102  and seal gaskets  101 . Crossbar  102  abuts housings  12  and  14 . The joint is sealed in a hygienic design by seal gaskets  101 . More importantly, it is used to precisely align and connect the first and second movable bearing blocks  59  and first stationary bearing block  77  in housing  12  with the same blocks in housing  14  with precision dowel pins  105  and fasteners  106 . This precise alignment is independent of the particular location of the stationary bearing blocks in housings  12  and  14 . 
     This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use embodiments of the example as required. However, it is to be understood that the invention can be carried out by specifically different devices and that various modifications can be accomplished without departing from the scope of the invention itself.