Patent Application
20080267761
The present invention is generally directed to stackers. More specifically, the present invention is directed to a stacker that can generally stack product in a vertical fashion at a high rate of speed and an interleaver, stacker and loading system for high speed food packaging.
Many manufacturing processes, particularly food handling processes, require the high speed stacking of products in a vertical fashion. Typically, to prevent the products from sticking together when packaged, refrigerated, and/or frozen, a high-speed paper, film, or foil interleaving system is used in conjunction with the stacker to insert a substrate beneath each individual product, which then serves as a separator between stacked products. The vertically stacked products are then typically loaded into a tray, box, or other container, or conveyed to a packaging machine.
Prior known stackers, for example for hamburger patties, typically run at 150 to 200 patties per minute for a single lane. Newer production techniques, however, allow production of patties at higher speeds for single lanes, for example, speeds of up to about 310 patties per minute. The known prior art stackers cannot keep up with the production speed, and thus the production speed is slowed or the product is split into two lanes for separate stacking. Higher cost or slower production results. It would therefore be desirable to address this with a stacker that allows faster production from the overall system by providing an improved high speed stacker.
Briefly stated, the present invention is directed to a stacker adapted to generally stack product in a vertical fashion. The stacker includes a first generally vertical conveyor having a first conveyor belt and a first plurality of flights mounted generally perpendicularly to the first conveyor belt. The first plurality of flights at least partially defines a plurality of stacking platforms. At least one positioning sensor for sensing a relative position of the flights is provided. An advancement sensor is provided for sensing product entering the stacker. A first drive incrementally drives the first conveyor responsive to the advancement sensor so that the stacking platforms descend. Each of the stacking platforms can receive a stack of the items to be stacked, and then be indexed downwardly to allow the next stack to be formed on the subsequent stacking platform.
In another preferred aspect of the invention, the stacker further includes a second generally vertical conveyor having a second conveyor belt and a second plurality of flights mounted generally perpendicularly to the second conveyor belt. The first and second conveyors are mounted opposite each other with the flights on facing sides of the first and second conveyors being generally aligned to define the stacking platforms, which are synchronously moved.
In another aspect, the invention provides a stacking-loading system for stacking and loading a lane of products. The system includes a feed conveyor for providing products in a lane and an interleaver that places a substrate under each of the products as they are carried by the feed conveyor. A stacker for stacking the interleaved product in a generally vertical fashion is provided, which is preferably of the type described above, with either the one or two conveyor belts with the flights defining stacking platforms. A removal conveyor that receives the stacked product from the stacker is also provided.
The invention also provides a method of stacking products which includes:
The following detailed description of the preferred embodiment of the present invention will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It is understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:
Certain terminology is used in the following description for convenience only and is not limiting. The words “right,” “left,” “top,” and “bottom” designate directions in the drawings to which reference is made. The term “containment space” means “the area bounded on the bottom by flights 220ai, 220bi, on top by flights 220ai+1, 220bi+1, in the rear by product stop 240, in the front by the feed conveyor, and on the sides by belts 210a, 210b, where i is 0, 1, 2, . . . n−1.” The words “a,” “and,” “one,” as used in the claims and in the corresponding portions of the specification, are defined as including one or more of the referenced item unless specifically stated otherwise. This terminology includes the words above specifically mentioned, derivatives thereof, and words of similar import.
Referring to
The system 10 further includes a stacker, generally designated 100, that receives the preferably interleaved product 110 for generally vertical stacking. Those skilled in the art will understand from the present disclosure that depending on the type of product, it may not be necessary to interleave the product with the substrate 60. A removal conveyor generally designated 104 is also preferably provided, or the stacked product can be placed in boxes or trays directly, which can be conveyed on the removal conveyor 104.
Briefly stated, the horizontal feed conveyor 102 conveys product 110, which can be provided with or without interleaving substrates by the interleaver 50, in a single lane to the stacker 100. The stacker 100 stacks the product 110 and places the stacked product in a tray or box, which is preferably, but not necessarily carried on the removal conveyor, or on the removal conveyor 104. The removal conveyor 104 conveys the stacked product to a packaging machine or an area for further processing.
The stacker 100 is preferably formed by two vertical conveyors 200a, 200b. The conveyors 200a, 200b are preferably positioned parallel to and facing each other. Specifically, the descending side of the belt 210a of conveyor 200a faces the descending side of the belt 210b of conveyor 200b. The conveyors 200a, 200b may alternatively be placed at a slight angle to create a funneling or tapering effect.
The belt 210a, 210b of each respective conveyor 200a, 200b has a plurality of flights, generally 220a, 220b, and more specifically 220a1, 220a2 . . . 220an; 220b1, 220b2 . . . 220bn extending generally perpendicularly outward from the surface of the belt 210a, 210b. Preferably, the total number of flights n is the same on each respective belt 210a, 210b. Furthermore, the relative positioning of the flights 220a1, 220a2 . . . 220an of belt 210a are identical to the relative positioning of flights 220b1, 220b2 . . . 220bn of belt 210b. The flights 220a, 220b on the facing sides of the belts 210a, 210b are aligned, as described hereinafter, directly across from each other to create a series of platforms for the product 110.
The conveyors 200a, 200b are spaced at a distance such that the aligned flights 220a, 220b have a space between them as they are moved in unison to preferably lower the series of platforms, with the space being less than the size of the product being stacked. A drop opening is created as the flights 220a, 220b round the lower roller 230a, 230b of each respective conveyor 200a, 200b. When the drop opening becomes larger than the size of the product 110 or stack of products 111, the product 110 or stack of products 111 passes between the flights 220a, 220b and drops to the removal conveyor 104. The spacing of the conveyors 200a, 200b and the dimension of the flights 220a, 220b can be adjusted to allow the stacker 100 to accommodate varying size products 110.
A product stop 240 is positioned between conveyors 200a, 200b on the rear of the stacker 100. The product stop 240 is positioned in the area of the stacker 100 where product 110 is received from the feed conveyor (not shown). The product stop 240 assists the orderly stacking of product 110 by confining all product 110 to the containment space. The product stop 240 further prevents the product 110 from overshooting the containment space.
The stacker 100 further comprises positioning photoelectric sensors 250a, 250b for sensing the location of each respective conveyor's 210a, 210b flights 220a, 220b. The positioning photoelectric sensors 250a, 250b are preferably mounted on the return (ascending) side of each respective conveyor 200a, 200b, and are vertically adjustable. An advancing product photoelectric sensor 255 is mounted adjacent to the feed conveyor 102 to sense product approaching the stacker 100. While photoelectric sensors are preferred, other types of positioning sensors could be used.
Preferably, the belts 210a, 210b of respective conveyors 200a, 200b are moved by servo drives 260a, 260b. Referring particularly now to
The exposed mechanics of the stacker 100 are preferably constructed from stainless steel. Where stainless steel cannot be used, sanitary materials are substituted. Sanitary design is also implemented where possible, such as, for example, reducing crevices, providing smooth, wipeable surfaces, and eliminating horizontal platforms where liquids may pool.
The stacker 100 is preferably controlled by a programmable logic controller (PLC). Other types of control systems are possible such as, for example, a distributed control system (DCS) or other similar control system. The PLC is preferably housed in a water-tight enclosure, such as a NEMA-4X enclosure, for example.
The stacker 100 of the present invention, upon initial startup, identifies the position of flights 220a, 220b in a procedure termed “homing”. The PLC instructs the servo drives 260a, 260b to perform the homing procedure, the characteristics of which are stored at the servo drives 260a, 260b. The servo drives 260a, 260b increment their respective belts 210a, 210b and flights 220a, 220b until the photoelectric sensors 250a, 250b sense the position of a flight. A variable offset distance from the positioning photoelectric sensors 250a, 250b to the sensed flight can be programmed so that products 110 of different thicknesses can be handled by the stacker 100. Upon completion of homing, the stacker 100 is ready to receive product 110 from the feed conveyor.
There are two motion profiles utilized by the stacker 100 for receiving product 110. The first motion profile is termed the stacking sequence. In the stacking sequence, the advancement photoelectric sensor 255 identifies an incoming product, for example a hamburger patty, approaching the stacker 100 on the horizontal feed conveyer at a high rate of speed. Upon sensing the incoming patty, the advancement sensor notifies the PLC of the incoming patty. After a programmed delay to allow the patty to enter and settle into the containment space (if this is the first patty in the group) or on to a previously stacked patty (if this is not the first patty in the group), the PLC instructs the servo drive to increment the flights 220a, 220b a programmed distance. The programmed distance is such that the next patty will come to rest on top of the first patty upon entering the containment space. A stack count, which is simply a count of the number of products 110 which have entered the stacker 100, is then incremented. This stacking sequence is repeated until the adjustable stack count is reached. It should be noted that while the stack count is adjustable, there is an upper limit to the height of the stack inherent in the spacing between flights 220a, 220b.
When the stack count reaches a programmed value, the PLC instructs the servo drive to execute the loading sequence. The loading sequence advances the flights 220a, 220b and stops the motion when the next set of flights is in the loading position, preferably when the positioning photoelectric sensor is triggered. The stack count is then reset to zero. An adjustable, programmable offset is provided for controlling the stopping position of the loading sequence. Additionally, the vertical position of the positioning photoelectric sensors 250a, 250b on each respective conveyor 200a, 200b is adjustable. When the stacker 100 executes the loading sequence, the product 110 or stack of products 111 that has moved to the lowest containment space is dropped onto the removal conveyor 104, as described above. A tray, box or other receptacle may be placed on, or be part of, the removal conveyor 104.
A thickness detecting photoelectric sensor, or other device capable of detecting thickness, can also be employed along the feed conveyor 102 to detect a thickness of product 110 fed into the stacker 100. Using the thickness detector, the travel distance of the flights 220a, 220b during stacking could be adjusted for each individual product 110 to be stacked, if desired. This is especially useful when stacking product that has considerable product thickness variability.
Additionally, depending on the type of product 110 being stacked, the position of the flights 220a, 220b can be adjusted so that the product does not slide from the conveyor system 102 onto the flights 220a, 220b or previously stacked product 110, but rather the flights or previously stacked product 110 are spaced downwardly from the level of the conveyor 102 so that the product 110 being stacked is lofted (i.e. airborne) as it travels onto the flights 220a, 220b or previously stacked product 110. This is especially important for soft or sticky products, such as fresh meat patties. The incremental movement down of the flights 220a, 220b can be pre-set for a particular product thickness for generally uniform thickness products, or can be adjusted based on the use of a product thickness sensor.
In another embodiment of the present invention, the stacker 100 can be used as an up or down elevator to raise or lower single products or stacked products to a higher or lower level in tight spaces. Especially, when space is limited and an inclined conveyor system is not practical.
Referring to
It should be understood by those skilled in the art that although the stacker-loader is depicted as having a manual crank 440 and ball screws 450, 470 for adjusting the spacing between the vertical conveyors 410a, 410b, a servo motor or other manual or automated device for achieving the adjustment can be easily implemented in connection with ball screws or other suitable linear guides and drives. A stacker-loader with automated adjustment of the spacing between the flights may also be equipped with a photoeye for sensing the size of an approaching product, and automatically adjusting the spacing of the vertical conveyors to accommodate the sensed product.
Referring to
One skilled in the art will recognize that the various automation techniques described above in reference to the single lane stacker can be implemented in this embodiment of the present invention. For example, optical sensors may be positioned along the feed conveyor 530 to detect incoming product 520, as described above. Optical sensors may also be positioned to determine the position of the flights of each vertical conveyor 510A, 510B, 510C, and for stepping the flights by way of a servo motor or other means controlled by a PLC, as described above. An interleaver may be positioned prior to the stacker-loader 500 for placing a substrate under the product 520 to be stacked, as described above. It should be understood that while three vertical conveyors are shown in
It will be recognized by those skilled in the art that changes may be made to the above described embodiments of the invention without departing from the broad inventive concept thereof. For example, the conveyers 200a, 200b need not be mounted vertically, but instead slightly offset from vertical. Similarly, the spacing of the flights 220a, 220b need not be uniform, thereby allowing stacking of various sized products. Additionally, for single flight stacking, such as using the stacking conveyors 510a, 510b, 510c, the product can hang over the edge of the flight to some extent. While a preferred embodiment of a stacker is shown, any conveyor having rollers can be used in conjunction with the system provided by the present invention.
It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but is intended to cover all modifications which are within the spirit and scope of the invention as defined by the appended claims; the above description; and/or shown in the attached drawings.
| Number | Date | Country | Kind |
|---|---|---|---|
| 60707292 | Aug 2005 | US | national |
| 60772008 | Feb 2006 | US | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US06/31068 | 8/9/2006 | WO | 00 | 1/23/2008 |
