Method for stacking meat patties

Method for stacking substantially flat products such as meat patties. Rows of patties are conveyed under a metal detector and then to a sigmoidal slide. Patties contaminated with metal trigger the metal detector to send a signal to the slide. Upon receipt of a signal from the metal detector, the slide pivots in a manner to dispose of metal contaminated patties. Uncontaminated patties are conveyed down the slide without flipping over and onto a second lower conveyor having a plurality of vertical blades mounted thereto, between which patties are received in stacks. An optical counter is mounted to count patties conveyed down the slide. The counter is in communication with the second indexed conveyor and signals such conveyor to move forward after a predetermined number of patties have been stacked between two adjacent vertical blades on the indexed conveyor. Stacks of patties are then conveyed on the second conveyor to a packing station where workers can grasp the stacks with each of their hands for packing into distribution boxes.

Field of the Invention 
This invention relates to a method and apparatus for forming organized 
stacks of products and particularly relates to a method and apparatus for 
selecting acceptable meat patties, counting such patties and stacking such 
patties in substantially aligned and uniform stacks for incorporation into 
distribution packages. 
Background of the Invention 
In packaging products such as meat patties for subsequent distribution, it 
is desirable to have the patties organized in stacks to facilitate easy 
handling and transfer of patties into packing boxes. In conventional meat 
pattie stacking methods and apparatuses, meat patties are often flipped or 
vertically dropped into stacked arrangement, creating misalignment of 
pattie stacks. Prior art methods and apparatuses which produce irregular 
pattie stacks delay a worker's handling of such stacks, thus slowing the 
entire packaging process. 
Moreover, prior art methods and apparatuses fail to address ergonomic 
concerns. For example, conventional methods often require a worker to use 
both of his/her hands when transferring patties from a conveyor into 
packaging boxes. The lack of efficiency of prior art methods also adds 
considerably to worker fatigue and adds significantly to the overall costs 
of the packaging operation. 
In prior art methods and apparatuses that form stacks by flipping meat 
patties, patties often fail to complete a 180.degree. rotation and thus 
land on their sides, damaging the individual pattie as well as the stack 
into which the pattie falls. Removing improperly stacked patties results 
in significant inefficiencies and delays in the packaging process. 
Numerous types of prior art stacking devices are known. For example, U.S. 
Pat. No. 3,998,339 by Booth discloses a pattie stacker which conveys a 
selected number of patties to form a substack on a stacker plate, 
subsequently removes the stacker plate and allows the substack to 
vertically drop into a finished stack. U.S. Pat. No. 4,759,433 by Kraft 
discloses an apparatus for stacking products one on top of the other by 
flipping the product 180.degree. onto the top of other patties to form a 
stack. U.S. Pat. No. 3,915,316 by Pomara discloses an apparatus for 
counting and stacking flat articles in which the articles are stacked 
against vertical tines positioned above a moving conveyor of laterally 
spaced belts. After a predetermined number of articles are stacked against 
the tines, the tines are rapidly retracted downward and the stack of 
articles are discharged on the moving conveyor. 
Other prior art inventions use mechanical means to straighten stacks after 
an initial stacking procedure. For example, U.S. Pat. No. 4,827,692 by 
Fiske discloses a mechanism for packaging hamburger patties wherein a 
continuously growing column of hamburger patties is created from a 
bottom-fed stacking device Fiske teaches the use of gripping means to 
manipulate stacked patties into columnar structures. 
Other inventions relate to forming stacks from sliced food patties such as 
sliced sausage patties. For example, U.S. Pat. No. 4,529,082 by Mally 
discloses a method and apparatus for aligning nonuniform stacks of sliced 
meat patties. 
U.S. Pat. No. 3,866,741 by Carbon discloses a stacker which conveys meat 
patties to the end of an input conveyor where the patties flip 180.degree. 
and fall onto a stationary stacking conveyor. To enable individual patties 
to rotate through a 180.degree. flip, the input conveyor must be 
positioned a certain defined distance above the stacking conveyor. The 
distance with which each pattie must fall, together with the 
non-uniformity of each flip of individual patties, results in the 
formation of misaligned pattie stacks. The Carbon apparatus includes a 
retractable separator guide which is mounted above the stacking conveyor, 
providing a space into which successive rows of patties fall to form 
pattie stacks. When a specified number of patties are stacked, the 
separator guide is lifted, the stacking conveyor is activated and the 
stacked patties are moved forward. The sudden lifting of the separator 
guide and the coincident movement forward of the pattie stack, disturbs 
the stack, causing individual patties to fall from the top of the stack 
and often into other stacks, resulting in a domino effect. The non-uniform 
partial stacks are then conveyed on the stacking conveyor in a disheveled 
state, making the task of picking up individual stacks difficult. Workers 
must use both hands to grab and organize the patties into stacks in order 
to remove the patties from the conveyor for packaging into shipping boxes. 
Because the size of each stack can vary in prior art devices, depending 
upon whether the stack has fallen over or has had patties fall off, 
workers must expend additional time organizing appropriate stacks of 
patties to ensure that each box contains a specified number of patties. 
In view of the above, a new method and apparatus is needed to consistently 
stack products in uniform and aligned stacks and to efficiently and 
effectively transfer such stacks to a packaging station. A method and 
apparatus is needed which can smoothly transfer products without the 
products rotating or falling from too great a height, in order to reduce 
the damage to individual products or to product stacks and to improve the 
efficiency of the whole packaging operation. An ergonomic method and 
apparatus is also needed in which workers can transport stacks of products 
from a conveyor into packaging boxes by using only one hand per stack. 
Additionally, a method and apparatus are needed which can detect defects, 
such as the presence of metal in the products and efficiently reject such 
defective products without a significant delay in the packaging operation. 
Summary of the Invention 
The present invention includes a method and apparatus for transferring 
substantially flat products such as meat patties from one moving conveyor 
onto another lower conveyor without flipping the products in the process. 
The invention further includes a method and apparatus for aligning 
successive rows of products into a stacked arrangement on a conveyor, the 
conveyor having a plurality of parallel spaced blades mounted thereon, 
between which products are received. The products are held in organized 
stacks during transport to a final packaging station. The present 
invention also provides a method and apparatus for detecting and disposing 
of metal contaminated products without undue delay in the packaging 
operation. 
In one embodiment of the present invention, patties are conveyed through a 
metal detector on a continuously moving conveyor surface. The metal 
detector inspects each row of patties being conveyed to determine whether 
any metal particles may be present in one or more of the patties. When 
metal particles are detected in a pattie, the metal detector sends a 
signal to a pivotally mounted slide, such slide being responsive to such 
signals. Upon receipt of a signal, the slide is pivoted to discharge metal 
contaminated patties into a disposal bin. 
The slide, in one embodiment of the invention, is pivotally mounted at an 
angle to receive patties from a first conveyor and transport the patties 
to a lower indexing conveyor. The slide is preferably sigmoidal in shape 
and positioned at an angle which allows for the efficient transport of 
patties to the indexed conveyor without the patties flipping over in the 
process. 
In another embodiment of the invention, a counter is provided for counting 
patties transferred down the slide. The counter is preferably an optical 
sensing device and one or more of such counters may be positioned to 
register the number of pattie rows being transported down the slide and 
onto the indexed conveyor. 
The indexed conveyor of the present invention is preferably provided with a 
plurality of parallel blades mounted approximately one pattie length from 
each other, between which stacks of meat patties are formed. Side walls to 
the indexed conveyor are also provided in one embodiment to facilitate the 
gathering of pattie stacks by packaging employees. 
In a further embodiment of the invention, a control device activates the 
indexed conveyor after receiving signals from the counter, thus moving the 
indexed conveyor forward to allow for further stacks of patties to be 
formed in an additional space between two parallel spaced blades.

Detailed Description of the Invention 
In accordance with the present invention, a method and apparatus are 
disclosed for stacking substantially flat products of generally uniform 
size and dimension. Although various products can be stacked with the 
present invention, it is especially useful for stacking "patties " As used 
herein, "patties" refers generally to flat food products and in particular 
to meat patties. For the sake of simplicity, the following description of 
the invention will be directed to the stacking of patties. However, it is 
to be expressly understood that the present invention can be practiced 
with other products, such as tortillas, cookies, pie pans, etc. 
In a preferred embodiment, the invention relates to the transport of 
partially frozen, preformed meat patties from a first conveyor to a second 
conveyor to form uniform and aligned stacks of patties which are ready for 
packaging into distribution boxes. The ease with which such uniform stacks 
can be handled by employees in pattie packaging operations results in 
significant improvements in efficiency, and thus reduces the costs 
associated with the pattie packaging process. 
The present invention is particularly adapted for use with partially frozen 
or frozen meat patties, as opposed to fresh meat patties. Patties may be 
initially formed and placed on wax paper or the like, and thereafter 
conveyed through either a spiral or tunnel refrigeration unit wherein 
carbon dioxide or nitrogen environments are used to cool the meat quickly. 
Frozen or partially frozen meat patties are less susceptible to 
deformation during the stacking process and may be better handled by 
employees during the packing of meat pattie stacks into distribution 
boxes. 
In general, the present invention includes a device for moving successive 
rows of patties in the same direction. In a preferred embodiment, the 
device for moving comprises a conveyor. Referring to FIG. 1, preformed, 
partially frozen patties 10 are transferred on a first conveyor 12 which 
includes an endless band 14, trained about rollers 16, 18. The first 
conveyor 12 can have substantially vertical blades mounted thereto to 
assist in the registration of rows of patties 10. The first conveyor 12 
transfers patties from a refrigerated environment (not shown) toward a 
packing station 20. As shown in FIG. 2, patties 10 are in a row of about 
three to fifteen patties 10 in each row, more preferably three to ten 
patties 10 and most preferably four to six patties 10. 
In one embodiment of the present invention, a metal detector 22 is 
positioned directly above the first conveyor 12. The metal detector 22 
senses the presence of metal particles that may have entered patties 10 
during prior processing. In a preferred embodiment, the metal detector 22 
is mounted separately from the first conveyor 12 to avoid any disruptive 
vibration that may be caused by the operation of the first conveyor 12. 
A device is provided that can transport patties from the first conveyor to 
a second lower conveyor. In one embodiment of the invention, this device 
is a slide 24 positioned in relation to the first conveyor 12 so as to 
avoid any hindrance of patties 10 being transferred from the first 
conveyor 12 to the slide 24. The slide 24 is preferably pivotally mounted 
at an angle sufficient to facilitate the smooth conveyance of patties 10 
down the slide 24, but is not mounted at so steep an angle as to allow for 
patties to flip or rotate. The slide 24 is preferably constructed from 
stainless steel, but other suitable materials can also be used. In 
particular, the slide 24 can comprise a bar roller 35B. (See FIG. 4). The 
bar roller 35B comprises a plurality of freely rotatable cylinders mounted 
adjacent to each other, that permit patties 10 placed thereon to be 
conveyed with minimal friction. The bar roller 35B is preferably of 
sufficient dimension to receive a row of patties 10 and is mounted so that 
patties 10 conveyed on the slide 24 are transported to the second conveyor 
32 without flipping over. 
While embodiments of the invention wherein a bar roller 35B makes up the 
slide 24 are possible (See FIG. 4), the slide 24 is preferably ccnstructed 
using a stainless steel flat portion 27 or a sigmoidal portion 25, in 
combination with a bar roller 35A and 35C due to difficulties encountered 
by solely using a bar roller 35B as the slide 24. Such difficulties 
include the sticking of individual rollers within a bar roller 35B due to 
meat falling between the rollers, freezing of water on the bar roller, 
etc. 
In a preferred embodiment, as shown in FIG. 5, a sigmoidal portion 25 of 
the slide 24 provides a generally short horizontal surface 2 to receive 
patties 10 from the first conveyor 12, a middle angled section 28 to allow 
the pattie 10 to be transported downward, and a final generally horizontal 
section 30 for transport of patties 10 onto the bar roller section 35C of 
the slide 24 and then to a second conveyor 32. The bar roller portion 35C 
is mounted directly below the sigmoidal portion 25 of the slide 24 to 
receive patties 10 transported by the sigmoidal portion 25 and to convey 
such patties 10 onto a second indexed conveyor 32. The patties 10 
preferably exit the bar roller 35C at a speed and horizontal angle that 
allows each individual pattie 10 to be aligned atop of other patties 10 to 
form a substantially organized stack 34, while preventing damage which 
results from individual patties 1 striking the stack 34 at an angle which 
deviates too greatly from the horizontal. 
In one embodiment of the present invention, a slide positioning device 36 
is provided for controlling the position of the slide 24. Such slide 
positioning device 36 is able to receive signals produced by the metal 
detector 22. When a meat pattie 10 contaminated with metal passes under 
the metal detector 22 a signal is generated which activates the slide 
positioning device 36. 
In one embodiment as shown in FIG. 3, the slide positioning device 36 is a 
piston, either pneumatically or hydraulically controlled, mounted to a 
substantially flat portion 27 of the slide 24 in such a manner as to 
reversibly move the flat portion 27 of the slide 24 from a first normal 
position, which permits patties 10 to be transported from the first 
conveyor 12 down the flat portion 27 of the slide 24, into an second 
activated position (shown in phantom in FIG. 3), which permits patties 10 
to fall into a disposal bin 38 (See FIG. 1). Thus, upon receipt of a 
signal from the metal detector 22, the slide positioning device 36 is 
activated, pivoting flat portion 24 of the slide 24 in such a manner that 
the row of meat patties 10 in which metal has been detected is directed 
into a receiving bin 38. The control device 36 then returns the flat 
portion 27 of the slide 24 to its normal functioning position to receive 
additional rows of patties 10. When the flat portion 27 of the slide 24 is 
not activated, patties 10 proceed down the flat portion 27 of the slide 24 
and onto a bar roller portion 35A of the slide 24 for transport to a 
second conveyor 32. In another embodiment, as shown in FIG. 4, the bar 
roller 35B is directly connected to the control device 36. The bar roller 
35B receives patties from the first conveyor 12 for transport to the 
second indexed conveyor 32. Other control devices such as springs, levers, 
cams, etc., can also be employed. 
Other embodiments of the invention include various ways to activate the 
slide 24 in order to dispose of patties 10. For example, the control 
device 36 can angularly adjust the slide 24 at a time when the meat pattie 
10 containing metal is on the slide's surface, thereby causing the pattie 
10 to be conveyed down the slide 24 at a steep angle and into a receiving 
bin 38. The objective in all embodiments is to dispose of contaminated 
patties 10 in a quick and efficient manner so that the overall packaging 
process is not delayed. 
In another embodiment of the invention (See FIGS. 1 and 2), a counter 42 is 
provided to count the number of meat patties 10 transferred down the slide 
24. In a preferred embodiment, the counter 42 is an optical sensing device 
which registers each time a pattie 10 is passed beneath its optical eye. 
The counter 42 is positioned so that it only counts meat patties 10 that 
are transferred down the slide 24 and onto the second conveyor 32. In this 
way, meat patties 40 rejected because they contain metal particles are not 
be registered by the counter, allowing accurate counts of packaged patties 
to be maintained. The counter 42 is preferably placed as close as possible 
to the meat patties 10 passing down the slide 24 and is in a position to 
"see" any meat patties 10 that may be slightly out of line with other meat 
patties 10 within a given row. In another embodiment of the invention, 
numerous optical counting devices can be used to detect each individual 
pattie 10 being transferred down the slide 24. 
A further feature of the invention is a second indexed conveyor 32 in 
general longitudinal alignment with the first conveyor 12. In a preferred 
embodiment, the second conveyor 32 comprises a driven endless belt 44 
trained over one or more rollers 45 (only one shown). The second conveyor 
32 is positioned below the discharge end of the first conveyor 12 and 
below the slide 24. At such position, the second conveyor 32 sequentially 
receives patties 10 being transferred from the first conveyor 12 down the 
slide 24. The indexed conveyor 32 is provided with a plurality of parallel 
partitions 46 mounted substantially perpendicular to the conveyor's 
direction of movement. The partitions 46 are separated by approximately 
the width of a single pattie, and are of sufficient height to allow for 
the alignment of stacks 34 of a predetermined height. When patties 10 are 
transferred down the slide 24 and onto the indexed conveyor 32, they are 
guided into a stacked relationship against each one of the plurality of 
substantially parallel, laterally spaced partitions 46 mounted to the 
second conveyor 32. The partitions 46 stop the forward progress of patties 
10 transferred down the slide 24 and act to align the patties 10 received 
in a stacked relationship. Side walls 37 are also provided on each side of 
the indexed conveyor 32, further aligning and organizing the stacks of 
patties 10 being transported to the packing station 20. 
In a preferred embodiment, the second conveyor 32 is moved forward in 
indexed steps in an intermittent forward motion, stopping to receive a 
predetermined number of patties 10 in a stacked arrangement 34 between 
each adjacent pair of parallel partitions 46 mounted on the second 
conveyor 32. An intermittent drive device (not shown) is provided which 
operatingly connects the counter 42 and the indexed conveyor 32 to control 
the indexed movement of the indexed conveyor 32, such device able to 
receive signals from the counter 42. Thus, when a predetermined number of 
patties 10 have been stacked in the space 48 between two adjacent 
partitions 46 on the indexed conveyor 32, the intermittent drive device 
receives a signal and activates the indexed conveyor 32 to move it 
forward, providing a new space 48 between two partitions 46 on the indexed 
conveyor 32 to receive additional patties 10 to be stacked. The 
intermittent drive device is preferably controlled by either pneumatic or 
hydraulic means. 
The intermittent drive device for the second conveyor is preferably mounted 
on one of the rollers 45 controlling the second conveyor 32, and is able 
to receive signals from the counter 42 in order to trigger forward indexed 
movement of the conveyor 32. 
By use of the present invention, the efficiency of the pattie stacking and 
packing process is greatly increased. In addition, because the invention 
better organizes pattie stacks, it is more ergonomic for workers, causing 
less stress on the job and less physical discomfort in the performance of 
routine duties. In particular, workers whose job it is to physically pick 
up individual stacks 34 of patties 10 and place such stacks 34 into 
distribution boxes, are able to use each of their hands separately to pick 
up and place pattie stacks 34 into distribution boxes. The aligned stacks 
34 positioned between the blades 46 on the second conveyor 32 allow 
workers to either grasp individual stacks 34 from a row of stacks 34, or 
to move aligned stacks 34 between the blades 46 to the side wall 37 and 
then grasp each stack 34 as it is biased against the side wall 37. This 
ability to grasp stacks 34 with a single hand results in significant 
advantages in efficiency, permitting the overall packing process to 
proceed at a faster rate without undue stress on workers. 
While various embodiments of the present invention have been described in 
detail, it is apparent that modifications and adaptations of those 
embodiments will occur to those skilled in the art. However, it is to be 
expressly understood that such modifications and adaptations are within 
the scope of the present invention, as set forth in the following claims.