Abstract:
A weight correction system for a slicing apparatus includes a weigh scale that weighs a draft of slices output from a slicer, a laser device arranged above the drafts of slices from the slicer, and a control that assigns a weight to each draft of slices, compares the weight to a pre-selected acceptable weight and determines a correction indicator representative of the number of slices to be added to or subtracted from each draft. The control commands the laser device to project the correction indicator onto a top slice of the draft. The laser device can project the correction indicator onto the draft as the draft is moving on a conveyor, or the laser device projects the correction indicator onto the drafts when the drafts are stationary, such as when the drafts are stationary in a packaging station.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a system used to monitor groups of food slices for correct weight. 
       BACKGROUND OF THE INVENTION 
       [0002]    In food processing, food product drafts can be a single food portion or a group of food portions such as a stack of slices. Food product drafts are sold according to a precise predetermined weight; under-weight drafts are rejected or supplemented with additional food slices and over-weight drafts are accepted but may represent an appreciable give-away and loss of revenue to the plant operator. 
         [0003]    Even with advanced controls, the slicing machines and like food product machines that produce groups of food products cannot always maintain those groups within the present tolerance limit. To minimize waste, it is desirable to correct any out-of-tolerance or “reject” food product groups. 
         [0004]    U.S. Pat. No. 5,109,936 to Ruppel describes a system that includes a slicing machine having a slicing blade and a feed mechanism, and uses feedback from primary and secondary weighing systems to control slice thickness in order to make proper weight. Another example is described in U.S. Pat. No. 3,846,958 to Divan. In this system, out-of-tolerance drafts are diverted to another location in order that an attendant may add or subtract product slices to make proper weight. Each of these patents is incorporated by reference herein. Common to all such systems is the fact that food products leaving the slicer are evaluated for weight and then slices of product are either added, or taken away to achieve an acceptable weight. 
         [0005]    It has previously been proposed that excess product can be reintroduced into the system to supplement drafts that are under-weight and therefore minimize waste. One example of such a “makeweight” method is set forth in U.S. Pat. No. 5,499,719 to Lindee et al., which is hereby incorporated by reference herein. This system uses a standalone take away and correction conveyor system for a food loaf slicer or other food product machine that produces groups of food products that must be held to close tolerance as to weight or some other readily measurable characteristics. There are two conveyors, one for reject groups and one for acceptable groups. The two conveyors are mounted on one base, spaced parallel in relation to each other, with the reject conveyor above the accept conveyor. A correction tray is used for correction of reject groups of food products. The correction tray is positioned adjacent to the reject and accept conveyors, so that an operator can divert reject groups from the reject conveyor to the correction receptacle, correct the reject groups at the correction receptacle to form acceptable groups therefrom, and deposit the corrected acceptable groups on the accept conveyor. 
         [0006]    Back bacon off-weight rejects from the Formax SNS® slicer are typically transferred to a conveyor at 90 degrees to the slicer. These reject stacks are manually taken off the conveyor and placed on a freestanding scale. The scale operator will add or remove slices to the rejected stacks in order to make an acceptable on-weight portion. These stacks are then hand-carried to the end of the slicing line in order to be manually introduced into the packaging machine. 
         [0007]    The present inventor has recognized this method is labor intensive. 
         [0008]    The present inventor has also recognized the desirability of providing a more efficient method for correcting weight of packaged food products. 
       SUMMARY OF THE INVENTION 
       [0009]    The invention provides and exemplary method of correcting the weight of portions produced by a machine, the portions being carried by a conveyor away from the machine. The method includes the steps of: transporting a portion on a conveyor away from the machine; weighing the portion and determining a deviation corresponding to an amount the portion is over or under a pre-selected weight; projecting an image onto the portion that represents the deviation; and making a correction to the amount of the portion that corresponds to the deviation. 
         [0010]    Preferably, the image is projected onto the portion while the portion is moving on the conveyor and the image moves with the portion. 
         [0011]    Alternately, the image is projected onto the portion while the portion is moving on the conveyor and the image does not move with the portion. The portion in effect moves through the image. 
         [0012]    Alternately, the image is projected onto the portion while the portion is stopped on the conveyor. This can occur in the packaging area. 
         [0013]    As an enhancement, a sensing whether the step of making a correction has been completed can occur and, if the step of making a correction has been completed, the image can be automatically turned off. 
         [0014]    Advantageously, the portion is a collection of slices and the machine is a slicing machine. The step of making a correction is further defined as adding a slice to or subtracting a slice from the collection. This can be done manually by a worker observing the laser image on the collection and adding a slice to or removing a slice from the collection. 
         [0015]    The invention provides a method of identifying under-weight and over-weight groups of food slices in order to manually correct the groups. 
         [0016]    The present invention provides a laser indicator system that can be used with a conveyor system, such as for a food slicing machine. Once a group of food slices is collected onto a conveyor as a draft and weighed, a laser image follows the food group and indicates whether the food group is under-weight or over-weight by illuminating a number on the top slice of the food group (0, −1, +1, etc.). If a food group is under-weight, the laser will specify how many slices are needed to make the food group make the correct, acceptable weight. If the food group is over-weight, the laser will specify how many slices need to be taken off to make correct weight without being unduly overweight, which constitutes “giveaway.” Once the under-weight or over-weight food group makes correct weight, this information can be fed back to the laser indicator system whereupon the system turns the laser off of this food group. The laser will then be reset to a home position to follow another group of food slices and indicate whether that food group is of sufficient weight, under-weight, or over-weight. 
         [0017]    Multiple laser devices can be used to simultaneously track multiple food slice groups or drafts, such as one laser for each lane of food groups carried on a multilane conveyor. Alternately, a single laser device can be provided for each column or lane of drafts that are carried on the conveyor. 
         [0018]    Alternately, the laser can project the slice correction indication in the packaging area. The indication can be directed onto the product after it has been placed into the packaging. In order to project the correct indication on the product, the control system tracks the product from the weigh scale to the packaging so that the correct indication can be projected onto the underweight or overweight stack or draft as loaded into the packaging array. 
         [0019]    If there is a dwell period wherein the entire array that is filled in the packaging station is stationary in the packaging station, the slice correction can be made to all stacks in the array during the dwell period. Alternately, the slice correction can be made while the packaging is indexed row by row at the packaging station. 
         [0020]    The components of the food slicing machine (input scale, slicing mechanism, output scale, etc.) can be similar to that in U.S. Pat. No. 5,628,237 or U.S. patent application Ser. No. 12/255,634 filed Oct. 21, 2008 or any variation thereof, these references being incorporated by reference herein. The laser in this system can be similar to that in U.S. Pat. Nos. 7,336,686; 6,874,893; 7,440,590; 7,408,558 or any variation thereof and are incorporated by reference therein. The laser indicator system is not limited to one laser; rather more than one laser can be used in the system. 
         [0021]    Numerous other advantages and features of the present invention will be become readily apparent from the following detailed description of the invention and the embodiments thereof, and from the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is an elevation view of a conveyor system and slicer incorporating the invention; and 
           [0023]      FIG. 2  is a plan view of the conveyor system and slicer of  FIG. 1 . 
           [0024]      FIG. 3  is an elevation view of another embodiment of the conveyor system and slicer of the present invention. 
           [0025]      FIG. 4  is a top view of a packaging location of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    While this invention is susceptible of embodiment in many different forms, there are shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
         [0027]      FIG. 1  is a side elevation view of a conveyor system  10  fed sliced products  11  by a food slicing machine  12 , such as a FX180® or PowerMax 4000™ slicer from Formax, Inc. of Mokena, Ill., USA. 
         [0028]    The slices  11  are collected on the conveyor system  10  as a stacked draft, shingled draft or loose draft  14  that are translated in the direction “X” on a conveyor surface  15  toward a packaging station  16 . 
         [0029]    A laser indicator system  24  contains at least one laser device  28  that communicates with a food slicing machine control unit  30  via a signal carrier, such as a cable  36 . 
         [0030]      FIG. 2  is a plan view of the conveyor system  10  and the food slicing machine  12 . Once a draft  14  of food slices  11  is collected on the conveyor it passes over a weigh scale  40 , and the weigh scale  40  measures the weight of the draft and communicates the weight to the control  30 . The weigh scale  40  conveys the weight information of each draft to the control unit  30  via a signal carrier, such as a cable  50 . The control unit  30  calculates the number of slices that need to be added or removed for that particular draft to make correct weight. In this regard the control unit  30  has a predetermined slice weight in memory. The control unit  30  conveys this information to the laser indicator system  24 , which then directs a laser beam  60  that illuminates the corresponding number (0, −1, +1, etc.) image  66  on the top slice of the food draft. If the weight is satisfactory the displayed number can be “0” or no indication at all. The laser indicator system  24  tracks the draft  14  until further information commands the laser device  28  to turn off the beam  60  displayed on that draft. 
         [0031]    To track the draft  14  as it is transported on the conveying surface  15 , the beam  60  must either be translated with the draft at a similar speed as it is transported in the direction “X”, or must be tilted as the drafts  14  are transported such as to always display the correction number on that draft. A laser tracking actuator  90  can comprise: a translating mechanism that moves the laser device  28  along the direction “X”; or a tilting mechanism that progressively tilts the laser device  28  (clockwise in  FIG. 1 ) to maintain the image  66  on the draft as it moves along the conveyor in the direction “X.” In either case, after a limited amount of travel of the draft, the actuator  90  must reset the laser device  28  to a home position to track a subsequent draft. The control  30  has as an input the speed of the conveying surface and the location of each completed draft on the conveying surface. This information is communicated to the laser system  24  particularly to the actuator  90 . 
         [0032]    Accordingly, a worker  70  is informed as to the number of slices required to be added or removed from a draft to make correct weight for that draft. The worker  70  can then add or remove a slice or slices from the drafts  14  displaying the particular number image  66  generated by the laser indicator system  24  as the drafts are moving on the conveyor. 
         [0033]    As an enhancement, once the appropriate slices have been added or deleted, the laser indicator system is turned off for that food group and such food group continues down the conveyor to the packaging unit. The laser indicator system can be automatically turned off and reset to a home position when the correction is made by one or a combination of the following examples: 
         [0034]    (1) the laser indicator senses an optical interruption of the laser path by the addition or removal of a slice or slices; or 
         [0035]    (2) a camera  110  senses the face of a new top slice compared to the face of a prior top slice sensed by a camera  112 , caused either by the addition or removal of a slice or slices, on the top of the draft; or 
         [0036]    (3) the laser device senses the draft has reached a certain point  120  on the conveyor. 
         [0037]    The cameras  110 ,  112  may be incorporated into the laser indicator system  24  or may stand alone. The camera  110  can communicate directly with the laser indicator system  24  to reset the laser indicator system  24  after a draft is adjusted or the cameras  110 ,  112  can communicate with the unit  30  via a signal carrier, such as a cable  126 , which will then communicate that the adjustment has occurred to the laser indicator system  24  via the signal carrier  36  to reset the laser device  28 . 
         [0038]    The laser indicator system does not need to divert “reject” groups to a separate location, nor does it need an additional conveyor in order to separate “reject” groups from groups that have made proper weight. As a result, the use of a laser to track groups of food slices permits “reject” groups to be identified and corrected by workers as the groups are moving toward the packaging station. The groups need not be stopped or redirected and weight correction can be made in a faster and more efficient manner than prior systems. 
         [0039]    A second embodiment is shown in  FIGS. 3 and 4 . Slicing machine  12  incorporates similar features, including a conveyor surface  15 , control unit  30 , and a laser device  28 . Food slices  11  are fed to the conveyor surface  15  from a slicing system. When the food slices  11  reach the end of conveyor surface  15 , they are transferred onto a declined loading conveyor surface  15   a  which loads the drafts into a packaging array  17  of trays  18  at the packaging station  16 . 
         [0040]    The arrays  17  of trays  18  are formed successively in a continuous web  19  of packaging film upstream of the packaging station  16 . The web  19  is pulled to the left in  FIG. 3  to move arrays  17  through the packaging station  16 . The arrays  17  are filled, either during a dwell period as upstream trays are being formed, as the array  17  is stationary in the packaging station, or filled row-by-row in index fashion as the array  17  enters the packaging station. The packaging array  17  moves longitudinally, with respect to conveyor surface  15   a , so drafts  14  of food slices  11  being transferred on conveyor surface  15   a  fall into trays  18 . 
         [0041]    Methods of filling trays are described in U.S. Pat. No. 7,065,936, herein incorporated by reference. 
         [0042]    A top view of food packaging  17  is shown in  FIG. 4 . Food packaging is shown with eight trays  18  to hold food slices  11  therein. Example images  66  of “+1,” “−1,” and “+2” projected onto the top slice of each draft  14  are shown. 
         [0043]    According to this embodiment, laser device  28  is located at the packaging station. An image  66  is projected onto the surface of the top food slice  11  by the laser device  28 . A worker  70  is present at the location of the packaging station  16 , to add or remove the required amount of food slices  11  according to the instruction of the image  66 . When the adjustment is made, a camera  110 , timer, or other apparatus, may be used to signal the correction has been made and turns off the display  66  from the laser device  28 . 
         [0044]    Because the packaging station is spaced downstream from the weigh scale  40 , the system control  30  must “track” the drafts so that the correct indication of stack underweight or overweight is projected on the stack or draft at the packaging station  16 . 
         [0045]    The laser or lasers can be configured to project an image onto the draft that follows the movement of the draft on the conveyor. Alternately, the draft can be moved through the laser projection wherein the laser doesn&#39;t follow the draft. In that case the image would only briefly be viewable on the draft as the draft is moved through the stationary laser projection. Alternately, the draft can be stopped on the conveyor and the image projected onto the draft from a laser that projects a stationary laser projection, i.e., the projection does not follow or track a moving draft. 
         [0046]    From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred.