Patent Application
20210229843
The invention generally relates to wrapping loads with packaging material through relative rotation of loads and a packaging material dispenser.
Various packaging techniques have been used to build a load of unit products and subsequently wrap them for transportation, storage, containment and stabilization, protection and waterproofing. One system uses wrapping machines to stretch, dispense, and wrap packaging material around a load. The packaging material may be pre-stretched before it is applied to the load. Wrapping can be performed as an inline, automated packaging technique that dispenses and wraps packaging material in a stretch condition around a load on a pallet to cover and contain the load. Stretch wrapping, whether accomplished by a turntable, rotating arm, vertical rotating ring, or horizontal rotating ring, typically covers the four vertical sides of the load with a stretchable packaging material such as polyethylene packaging material. In each of these arrangements, relative rotation is provided between the load and the packaging material dispenser to wrap packaging material about the sides of the load.
A primary metric used in the shipping industry for gauging overall wrapping effectiveness is containment force, which is generally the cumulative force exerted on the load by the packaging material wrapped around the load. Containment force depends on a number of factors, including the number of layers of packaging material, the thickness, strength and other properties of the packaging material, the amount of pre-stretch applied to the packaging material, and the wrap force or tension applied to the load while wrapping the load. An insufficient containment force can lead to undesirable shifting of a wrapped load during later transportation or handling, and may in some instances result in damaged products. On the other hand, due to environmental, cost and weight concerns, an ongoing desire exists to reduce the amount of packaging material used to wrap loads, typically through the use of thinner, and thus relatively weaker packaging materials and/or through the application of fewer layers of packaging material. As such, maintaining adequate containment forces in the presence of such concerns can be a challenge.
One challenge associated with conventional wrapping machines is due to the difficulty in selecting appropriate control parameters to ensure that an adequate containment force is applied to a load. In many wrapping machines, the width of the packaging material is significantly less than the height of the load, and a lift mechanism is used to move an elevator or roll carriage in a direction generally parallel to the axis of rotation of the wrapping machine as the load is being wrapped, which results in the packaging material being wrapped in a generally spiral manner around the load. Conventionally, an operator is able to control a number of wraps around the bottom of the load, a number of wraps around the top of the load, and a speed of the roll carriage as it traverses between the top and bottom of the load to manage the amount of overlap between successive wraps of the packaging material. In some instances, control parameters may also be provided to control an amount of overlap (e.g., in inches) between successive wraps of packaging material.
The control of the roll carriage in this manner, when coupled with the control of the wrap force applied during wrapping, may result in some loads that are wrapped with insufficient containment force throughout, or that consume excessive packaging material (which also has the side effect of increasing the amount of time required to wrap each load). In part, this may be due in some instances to an uneven distribution of packaging material, as it has been found that the overall integrity of a wrapped load is based on the integrity of the weakest portion of the wrapped load. Thus, if the packaging material is wrapped in an uneven fashion around a load such that certain portions of the load have fewer layers of overlapping packaging material and/or packaging material applied with a lower wrap force, the wrapped load may lack the desired integrity regardless of how well it is wrapped in other portions.
Ensuring even and consistent containment force throughout a load, however, has been found to be challenging, particularly for less experienced operators. Traditional control parameters such as wrap force, roll carriage speed, etc. frequently result in significant variances in number of packaging material layers and containment forces applied to loads from top to bottom. Furthermore, many operators lack sufficient knowledge of packaging material characteristics and comparative performance between different brands, thicknesses, materials, etc., so the use of different packaging materials often further complicates the ability to provide even and consistent wrapped loads.
As an example, many operators will react to excessive film breaks by simply reducing wrap force, which leads to inadvertent lowering of cumulative containment forces below desired levels. The effects of insufficient containment forces, however, may not be discovered until much later, when wrapped loads are loaded into trucks, ships, airplanes or trains and subjected to typical transit forces and conditions. Failures of wrapped loads may lead to damaged products during transit, loading and/or unloading, increasing costs as well as inconveniencing customers, manufacturers and shippers alike. Another approach may be to simply lower the speed of a roll carriage and increase the amount of packaging material applied in response to loads being found to lack adequate containment force; however, such an approach may consume an excessive amount of packaging material, thereby increasing costs and decreasing the throughput of a wrapping machine.
In addition, wrapping machines are finding use in connection with more and more applications where the loads to be wrapped differ in some respect from the traditional, cuboid-shaped loads consisting principally of regularly-stacked and substantially rigid cartons of products. Some loads, for example, may include portions or layers, herein referred to as inboard portions, that are substantially inboard of a supporting body upon which they are disposed and to which they must be secured. For example, loads that are palletized using an automated pallet picker may end up with less than complete layers of products on the top layer, and as such the top layer may be substantially inboard from the corners of the main body of the load. In some instances, only one product, or one case of products, may be placed on the top layer of the load. As another example, some loads may have a “ragged” topography due to the inclusion of multiple products or cases of products having varying elevations at different points across the top of the load. As another example, some products loaded onto pallets may be substantially smaller in cross-section than a pallet, and may therefore be substantially inboard from the corners of the pallet. Still other loads may include uncartoned and easily compressible products that may be susceptible to compression or twisting due to excessive wrap force applied during a wrapping operation. Still other loads may include top sheets or slip sheets that are placed on top of a load to protect the top of a load from dust, moisture or damage from another load stacked on top of the load.
Each of these situations places greater demands on a wrapping machine, as well as on an operator of the wrapping machine, to ensure that loads are sufficiently contained. Further, in some situations a wrapping machine may be incapable of adequately wrapping a load regardless of how it is set by an operator.
Therefore, a significant need continues to exist in the art for an improved manner of reliably and efficiently controlling a wrapping machine.
The invention addresses these and other problems associated with the art by providing a method, apparatus and program product that perform automatic load profiling to optimize a wrapping operation performed with a stretch wrapping machine. Automatic load profiling may be performed, for example, to determine a density parameter for a load that is indicative of load stability such that one or more control parameters may be configured for a wrapping operation based upon the density parameter. Automatic load profiling may also be performed, for example, to detect a load with a nonstandard top layer, e.g., a load with a top or slip sheet, a load with an easily deformable top layer, a load with a ragged top surface topography and/or a load with an inboard portion, such that a top layer containment operation may be activated during wrapping to optimize containment for the load.
Therefore, consistent with one aspect of the invention, a method of controlling a load wrapping apparatus of the type configured to wrap a load on a load support with packaging material dispensed from a packaging material dispenser through relative rotation between the packaging material dispenser and the load support may include sensing a plurality of points on a plurality of surfaces of the load using one or more sensors directed at the load, generating a surface model of the load based upon the sensed plurality of points, where the generated surface model identifies a top surface topography including a plurality of elevations for the load, and controlling one or more control parameters for the load wrapping apparatus when wrapping the load based upon the generated surface model.
In some embodiments, the one or more sensors includes a digital camera, a range imaging sensor or a three-dimensional scanning sensor. Also, in some embodiments, the one or more sensors includes first and second height sensors operatively coupled for substantially vertical movement with the packaging material dispenser and respectively configured to detect elevations for a main body and an inboard portion of the load. In addition, some embodiments may further include determining a density parameter for the load from the generated surface model.
Some embodiments may further include determining a weight parameter for the load, where determining the density parameter includes determining a volume and/or height of the load from the generated surface model and determining the density parameter based upon the determined volume and/or height and the determined weight parameter. Further, in some embodiments, determining the weight parameter includes measuring a weight of the load using a weight sensor.
In some embodiments, determining the volume and/or height of the load includes determining the volume from a length, a width and a height of the load. In addition, in some embodiments, determining the volume from the length, the width and the height of the load includes determining at least one of the length, the width and the height of the load using the generated surface model. In some embodiments, controlling the one or more control parameters for the load wrapping apparatus when wrapping the load based upon the generated surface model includes determining a stability for the load based upon the determined density parameter. In some embodiments, controlling the one or more control parameters for the load wrapping apparatus when wrapping the load based upon the generated surface model includes determining a containment force requirement for the load based upon the determined density parameter. In some embodiments, controlling the one or more control parameters for the load wrapping apparatus when wrapping the load based upon the generated surface model includes determining a wrap force or a number of layers of packaging material to be applied to the load based upon the determined density parameter.
In addition, some embodiments may also include determining whether the load has a nonstandard top layer based upon the generated surface model. In addition, some embodiments may further include determining whether the load has an inboard portion based upon the generated surface model. Some embodiments may also include determining dimensions of the inboard portion of the load based upon the generated surface model.
In some embodiments, controlling the one or more control parameters for the load wrapping apparatus when wrapping the load based upon the generated surface model includes activating a top layer containment operation when wrapping the load based upon determining the load has a nonstandard top layer. In some embodiments, controlling the one or more control parameters for the load wrapping apparatus when wrapping the load based upon the generated surface model further includes selecting the activated top layer containment operation from among a plurality of top layer containment operations based upon the generated surface model.
In some embodiments, the plurality of top layer containment operations includes a cross wrap containment operation and a U wrap containment operation, and in some embodiments, selecting the activated top layer containment operation from among the plurality of top layer containment operations includes selecting between the cross wrap containment operation and the U wrap containment operation based upon at least one dimension of an inboard portion of the load determined from the generated surface model.
In addition, in some embodiments controlling the one or more control parameters for the load wrapping apparatus when wrapping the load based upon the generated surface model further includes controlling one or more control parameters for the top layer containment operation based upon the generated surface model. In addition, in some embodiments, controlling the one or more control parameters for the top layer containment operation includes controlling one or more of an elevation of a web of packaging material, a width of the web of packaging material, an elevation of an elevator of a packaging material dispenser, a speed of the elevator, an activation state of a roping mechanism, an elevation change start time, an elevation change start angle, or a top edge contact point based upon the generated surface model.
Some embodiments may further include determining a verticality of at least one side of the load based upon the generated surface model. Also, in some embodiments, controlling the one or more control parameters for the load wrapping apparatus when wrapping the load based upon the generated surface model includes selecting or configuring a wrap profile for the load based upon the generated surface model.
Consistent with another aspect of the invention, a method of controlling a load wrapping apparatus of the type configured to wrap a load on a load support with packaging material dispensed from a packaging material dispenser through relative rotation between the packaging material dispenser and the load support may include determining a density parameter for the load prior to wrapping the load, and controlling one or more control parameters for the load wrapping apparatus when wrapping the load based upon the determined density parameter for the load.
Some embodiments may also include determining a weight parameter and a volume and/or height of the load, where determining the density parameter includes determining the density parameter from the weight parameter and the volume and/or height of the load. In addition, in some embodiments, determining the weight parameter of the load includes measuring a weight of the load using a weight sensor.
Also, in some embodiments, determining the volume and/or height of the load includes determining the volume from a length, a width and a height of the load. Moreover, in some embodiments, the load includes an inboard portion, and determining the volume from the length, the width and the height of the load includes determining the volume from a plurality of lengths, widths and heights of the load.
Some embodiments may further include sensing a plurality of points on a plurality of surfaces of the load using one or more sensors directed at the load and generating a surface model of the load based upon the sensed plurality of points, where the generated surface model identifies a top surface topography including a plurality of elevations for the load, and where determining the volume includes determining the volume based upon the generated surface model.
Consistent with another aspect of the invention, a method of controlling a load wrapping apparatus of the type configured to wrap a load on a load support with packaging material dispensed from a packaging material dispenser through relative rotation between the packaging material dispenser and the load support may include sensing a plurality of points on a plurality of surfaces of the load using one or more sensors directed at the load, determining whether the load has a nonstandard top layer based upon the sensed plurality of points, and selectively controlling the load wrapping apparatus to perform a top layer containment operation on the load during wrapping of the load based upon determining that the load has a nonstandard top layer.
Also, in some embodiments, determining whether the load has a nonstandard top layer includes determining whether the load includes an inboard portion. Also, in some embodiments, selectively controlling the load wrapping apparatus to perform the top layer containment operation includes selecting the top layer containment operation from among a plurality of top layer containment operations. Further, in some embodiments, the plurality of top layer containment operations includes a cross wrap containment operation and a U wrap containment operation. Further, in some embodiments, selecting the top layer containment operation from among the plurality of top layer containment operations includes selecting between the cross wrap containment operation and the U wrap containment operation based upon at least one dimension of the inboard portion of the load.
In some embodiments, selecting between the cross wrap containment operation and the U wrap containment operation is based upon a thickness of the inboard portion of the load. In addition, in some embodiments, selectively controlling the load wrapping apparatus to perform the top layer containment operation includes controlling one or more control parameters for the top layer containment operation based upon the sensed plurality of points.
Also, in some embodiments, controlling the one or more control parameters for the top layer containment operation includes controlling one or more of an elevation of a web of packaging material, a width of the web of packaging material, an elevation of an elevator of a packaging material dispenser, a speed of the elevator, an activation state of a roping mechanism, an elevation change start time, an elevation change start angle, or a top edge contact point based upon the sensed plurality of points. Some embodiments may also include generating a surface model of the load based upon the sensed plurality of points, where the generated surface model identifies a top surface topography including a plurality of elevations for the load, and where determining whether the load has a nonstandard top layer is based upon the generated surface model.
Consistent with yet another aspect of the invention, a method of controlling a load wrapping apparatus of the type configured to wrap a load on a load support with packaging material dispensed from a packaging material dispenser through relative rotation between the packaging material dispenser and the load support may include sensing whether the load includes an inboard portion using at least one sensor directed at the load, and in response to sensing that the load includes an inboard portion, automatically activating a top layer containment operation during wrapping of the load to secure the inboard portion to a supporting body of the load.
In some embodiments, sensing whether the load includes the inboard portion includes sensing an elevation of the inboard portion that is different from an elevation of the supporting body. Further, in some embodiments, activating the top layer containment operation includes performing a cross wrap containment operation or a U wrap containment operation. Some embodiments may further include, in response to sensing that the load includes the inboard portion, selecting the top layer containment operation from among a plurality of top layer containment operations. In some embodiments, the plurality of top layer containment operations includes a cross wrap containment operation and a U wrap containment operation, and where selecting the top layer containment operation from among the plurality of top layer containment operations includes selecting between the cross wrap containment operation and the U wrap containment operation based upon a sensed elevation of the inboard portion of the load relative to that of the supporting body.
Consistent with another aspect of the invention, a method of controlling a load wrapping apparatus of the type configured to wrap a load on a load support with packaging material dispensed from a packaging material dispenser through relative rotation between the packaging material dispenser and the load support may include sensing a plurality of points on a plurality of surfaces of the load using one or more sensors directed at the load, determining at least one dimension of the load from the sensed plurality of points, determining a weight parameter for the load, determining a wrap force control parameter and a minimum layer control parameter based upon the determined at least one dimension and the determined weight parameter, and controlling the load wrapping apparatus when wrapping the load using the determined wrap force and minimum layer control parameters.
Some embodiments may further include sensing a weight of the load, where determining the weight parameter includes determining the weight parameter based upon the sensed weight. Also, in some embodiments, sensing the plurality of points and sensing the weight are performed during conveying of the load to the wrapping apparatus. In addition, in some embodiments, sensing the plurality of points is performed by a distance sensor disposed overhead of a conveyor, and sensing the weight is performed by a load cell coupled to the conveyor. In some embodiments, determining the wrap force control parameter and the minimum layer control parameter based upon the determined at least one dimension and the determined weight parameter includes one or more of a containment force requirement for the load, a stability for the load or a density parameter for the load.
Some embodiments may also include detecting an inboard load from the sensed plurality of points, and activating an inboard load containment operation when wrapping the load in response to detecting the inboard load. In addition, in some embodiments, the inboard load containment operation reduces the wrap force control parameter when wrapping around a pallet. In addition, some embodiments may further include detecting a degree to which the load is inboard of the pallet, where activating the inboard load containment operation includes activating an inboard load containment operation that reduces the wrap force control parameter when wrapping around a pallet and that applies an additional band of packaging material around the load above the pallet in response to the detected degree. In addition, some embodiments may also include detecting an irregular load from the sensed plurality of points, and reducing the wrap force control parameter in response to detecting the irregular load.
In addition, some embodiments may also include automatically increasing the minimum layer control parameter in response to reducing the wrap force control parameter in order to maintain a containment force requirement for the load. Some embodiments may also include determining whether the load has a nonstandard top layer based upon the sensed plurality of points, and activating a top layer containment operation when wrapping the load in response to determining that the load has a nonstandard top layer.
Some embodiments may also include an apparatus for wrapping a load with packaging material and including a packaging material dispenser configured to dispense packaging material to the load, a drive mechanism configured to provide relative rotation between the packaging material dispenser and the load about an axis of rotation, and a controller configured to perform any of the aforementioned methods. In addition, some embodiments may also include a non-transitory computer readable medium and program code stored on the non-transitory computer readable medium and configured to control a load wrapping apparatus of the type configured to wrap a load with packaging material dispensed from a packaging material dispenser through relative rotation between the packaging material dispenser and the load, where the program code is configured to control the load wrapping apparatus by performing any of the aforementioned methods.
These and other advantages and features, which characterize the invention, are set forth in the claims annexed hereto and forming a further part hereof. However, for a better understanding of the invention, and of the advantages and objectives attained through its use, reference should be made to the Drawings, and to the accompanying descriptive matter, in which there is described example embodiments of the invention.
Embodiments consistent with the invention perform automatic load profiling to optimize a wrapping operation performed with a stretch wrapping machine. Automatic load profiling may be performed, for example, to determine a density parameter for a load that is indicative of load stability such that one or more control parameters may be configured for a wrapping operation based upon the density parameter. Automatic load profiling may also be performed, for example, to detect a load with a nonstandard top layer, e.g., a load with a top or slip sheet, a load with an easily deformable top layer, a load with a ragged top surface topography and/or a load with an inboard portion, such that a top layer containment operation may be activated during wrapping to optimize containment for the load. Prior to a further discussion of these various techniques, however, a brief discussion of various types of wrapping apparatus within which the various techniques disclosed herein may be implemented is provided.
Various wrapping apparatus configurations may be used in various embodiments of the invention. For example,
Packaging material dispenser 106 may include a pre-stretch assembly 112 configured to pre-stretch packaging material before it is applied to load 110 if pre-stretching is desired, or to dispense packaging material to load 110 without pre-stretching. Pre-stretch assembly 112 may include at least one packaging material dispensing roller, including, for example, an upstream dispensing roller 114 and a downstream dispensing roller 116. It is contemplated that pre-stretch assembly 112 may include various configurations and numbers of pre-stretch rollers, drive or driven roller and idle rollers without departing from the spirit and scope of the invention.
The terms “upstream” and “downstream,” as used in this application, are intended to define positions and movement relative to the direction of flow of packaging material 108 as it moves from packaging material dispenser 106 to load 110. Movement of an object toward packaging material dispenser 106, away from load 110, and thus, against the direction of flow of packaging material 108, may be defined as “upstream.” Similarly, movement of an object away from packaging material dispenser 106, toward load 110, and thus, with the flow of packaging material 108, may be defined as “downstream.” Also, positions relative to load 110 (or a load support surface 118) and packaging material dispenser 106 may be described relative to the direction of packaging material flow. For example, when two pre-stretch rollers are present, the pre-stretch roller closer to packaging material dispenser 106 may be characterized as the “upstream” roller and the pre-stretch roller closer to load 110 (or load support 118) and further from packaging material dispenser 106 may be characterized as the “downstream” roller.
A packaging material drive system 120, including, for example, an electric motor 122, may be used to drive dispensing rollers 114 and 116. For example, electric motor 122 may rotate downstream dispensing roller 116. Downstream dispensing roller 116 may be operatively coupled to upstream dispensing roller 114 by a chain and sprocket assembly, such that upstream dispensing roller 114 may be driven in rotation by downstream dispensing roller 116. Other connections may be used to drive upstream roller 114 or, alternatively, a separate drive (not shown) may be provided to drive upstream roller 114.
Downstream of downstream dispensing roller 116 may be provided one or more idle rollers 124, 126 that redirect the web of packaging material, with the most downstream idle roller 126 effectively providing an exit point 128 from packaging material dispenser 102, such that a portion 130 of packaging material 108 extends between exit point 128 and a contact point 132 where the packaging material engages load 110 (or alternatively contact point 132′ if load 110 is rotated in a counter-clockwise direction).
Wrapping apparatus 100 also includes a relative rotation assembly 134 configured to rotate rotating arm 104, and thus, packaging material dispenser 106 mounted thereon, relative to load 110 as load 110 is supported on load support surface 118. Relative rotation assembly 134 may include a rotational drive system 136, including, for example, an electric motor 138. It is contemplated that rotational drive system 136 and packaging material drive system 120 may run independently of one another. Thus, rotation of dispensing rollers 114 and 116 may be independent of the relative rotation of packaging material dispenser 106 relative to load 110. This independence allows a length of packaging material 108 to be dispensed per a portion of relative revolution that is neither predetermined nor constant. Rather, the length may be adjusted periodically or continuously based on changing conditions. In other embodiments, however, packaging material dispenser 106 may be driven proportionally to the relative rotation, or alternatively, tension in the packaging material extending between the packaging material dispenser and the load may be used to drive the packaging material dispenser.
Wrapping apparatus 100 may further include a lift assembly 140. Lift assembly 140 may be powered by a lift drive system 142, including, for example, an electric motor 144, that may be configured to move roll carriage 102 vertically relative to load 110. Lift drive system 142 may drive roll carriage 102, and thus packaging material dispenser 106, generally in a direction parallel to an axis of rotation between the packaging material dispenser 106 and load 110 and load support surface 118. For example, for wrapping apparatus 100, lift drive system 142 may drive roll carriage 102 and packaging material dispenser 106 upwards and downwards vertically on rotating arm 104 while roll carriage 102 and packaging material dispenser 106 are rotated about load 110 by rotational drive system 136, to wrap packaging material spirally about load 110.
In some embodiments, one or more of downstream dispensing roller 116, idle roller 124 and idle roller 126 may include a sensor to monitor rotation of the respective roller. In addition, in some embodiments, wrapping apparatus may also include an angle sensor for determining an angular relationship between load 110 and packaging material dispenser 106 about a center of rotation 154. In other embodiments, an angular relationship may be represented and/or measured in units of time, based upon a known rotational speed of the load relative to the packaging material dispenser, from which a time to complete a full revolution may be derived such that segments of the revolution time would correspond to particular angular relationships. Other sensors may also be used to determine the height and/or other dimensions of a load, among other information.
Wrapping apparatus 100 may also include additional components used in connection with other aspects of a wrapping operation. For example, a clamping device 159 may be used to grip the leading end of packaging material 108 between cycles. In addition, a conveyor (not shown) may be used to convey loads to and from wrapping apparatus 100. Other components commonly used on a wrapping apparatus will be appreciated by one of ordinary skill in the art having the benefit of the instant disclosure.
An example schematic of a control system 160 for wrapping apparatus 100 is shown in
Controller 170 in the embodiment illustrated in
For the purposes of the invention, controller 170 may represent practically any type of computer, computer system, controller, logic controller, or other programmable electronic device, and may in some embodiments be implemented using one or more networked computers or other electronic devices, whether located locally or remotely with respect to the various drive systems 120, 136 and 142 of wrapping apparatus 100.
Controller 170 typically includes a central processing unit including at least one microprocessor coupled to a memory, which may represent the random access memory (RAM) devices comprising the main storage of controller 170, as well as any supplemental levels of memory, e.g., cache memories, non-volatile or backup memories (e.g., programmable or flash memories), read-only memories, etc. In addition, the memory may be considered to include memory storage physically located elsewhere in controller 170, e.g., any cache memory in a processor in CPU 52, as well as any storage capacity used as a virtual memory, e.g., as stored on a mass storage device or on another computer or electronic device coupled to controller 170. Controller 170 may also include one or more mass storage devices, e.g., a floppy or other removable disk drive, a hard disk drive, a direct access storage device (DASD), an optical drive (e.g., a CD drive, a DVD drive, etc.), and/or a tape drive, among others. Furthermore, controller 170 may include an interface 190 with one or more networks 192 (e.g., a LAN, a WAN, a wireless network, and/or the Internet, among others) to permit the communication of information to the components in wrapping apparatus 100 as well as with other computers and electronic devices, e.g. computers such as a desktop computer or laptop computer 194, mobile devices such as a mobile phone 196 or tablet 198, multi-user computers such as servers or cloud resources, etc. Controller 170 operates under the control of an operating system, kernel and/or firmware and executes or otherwise relies upon various computer software applications, components, programs, objects, modules, data structures, etc. Moreover, various applications, components, programs, objects, modules, etc. may also execute on one or more processors in another computer coupled to controller 170, e.g., in a distributed or client-server computing environment, whereby the processing required to implement the functions of a computer program may be allocated to multiple computers over a network.
In general, the routines executed to implement the embodiments of the invention, whether implemented as part of an operating system or a specific application, component, program, object, module or sequence of instructions, or even a subset thereof, will be referred to herein as “computer program code,” or simply “program code.” Program code typically comprises one or more instructions that are resident at various times in various memory and storage devices in a computer, and that, when read and executed by one or more processors in a computer, cause that computer to perform the steps necessary to execute steps or elements embodying the various aspects of the invention. Moreover, while the invention has and hereinafter will be described in the context of fully functioning controllers, computers and computer systems, those skilled in the art will appreciate that the various embodiments of the invention are capable of being distributed as a program product in a variety of forms, and that the invention applies equally regardless of the particular type of computer readable media used to actually carry out the distribution.
Such computer readable media may include computer readable storage media and communication media. Computer readable storage media is non-transitory in nature, and may include volatile and non-volatile, and removable and non-removable media implemented in any method or technology for storage of information, such as computer-readable instructions, data structures, program modules or other data. Computer readable storage media may further include RAM, ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other solid state memory technology, CD-ROM, digital versatile disks (DVD), or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and which can be accessed by controller 170. Communication media may embody computer readable instructions, data structures or other program modules. By way of example, and not limitation, communication media may include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of any of the above may also be included within the scope of computer readable media.
Various program code described hereinafter may be identified based upon the application within which it is implemented in a specific embodiment of the invention. However, it should be appreciated that any particular program nomenclature that follows is used merely for convenience, and thus the invention should not be limited to use solely in any specific application identified and/or implied by such nomenclature. Furthermore, given the typically endless number of manners in which computer programs may be organized into routines, procedures, methods, modules, objects, and the like, as well as the various manners in which program functionality may be allocated among various software layers that are resident within a typical computer (e.g., operating systems, libraries, API's, applications, applets, etc.), it should be appreciated that the invention is not limited to the specific organization and allocation of program functionality described herein.
In the discussion hereinafter, the hardware and software used to control wrapping apparatus 100 is assumed to be incorporated wholly within components that are local to wrapping apparatus 100 illustrated in
Now turning to
Packaging material dispenser 206 may include a pre-stretch assembly 212 including an upstream dispensing roller 214 and a downstream dispensing roller 216, and a packaging material drive system 220, including, for example, an electric motor 222, may be used to drive dispensing rollers 214 and 216. Downstream of downstream dispensing roller 216 may be provided one or more idle rollers 224, 226, with the most downstream idle roller 226 effectively providing an exit point 228 from packaging material dispenser 206, such that a portion 230 of packaging material 208 extends between exit point 228 and a contact point 232 where the packaging material engages load 210.
Wrapping apparatus 200 also includes a relative rotation assembly 234 configured to rotate rotating ring 204, and thus, packaging material dispenser 206 mounted thereon, relative to load 210 as load 210 is supported on load support surface 218. Relative rotation assembly 234 may include a rotational drive system 236, including, for example, an electric motor 238. Wrapping apparatus 200 may further include a lift assembly 240, which may be powered by a lift drive system 242, including, for example, an electric motor 244, that may be configured to move rotating ring 204 and roll carriage 202 vertically relative to load 210. In addition, similar to wrapping apparatus 100, wrapping apparatus 200 may include various sensors, as well as additional components used in connection with other aspects of a wrapping operation, e.g., a clamping device 259 may be used to grip the leading end of packaging material 208 between cycles.
Packaging material dispenser 306 may include a pre-stretch assembly 312 including an upstream dispensing roller 314 and a downstream dispensing roller 316, and a packaging material drive system 320, including, for example, an electric motor 322, may be used to drive dispensing rollers 314 and 316, and downstream of downstream dispensing roller 316 may be provided one or more idle rollers 324, 326, with the most downstream idle roller 326 effectively providing an exit point 328 from packaging material dispenser 306, such that a portion 330 of packaging material 308 extends between exit point 328 and a contact point 332 (or alternatively contact point 332′ if load 310 is rotated in a counter-clockwise direction) where the packaging material engages load 310.
Wrapping apparatus 300 also includes a relative rotation assembly 334 configured to rotate turntable 304, and thus, load 310 supported thereon, relative to packaging material dispenser 306. Relative rotation assembly 334 may include a rotational drive system 336, including, for example, an electric motor 338. Wrapping apparatus 300 may further include a lift assembly 340, which may be powered by a lift drive system 342, including, for example, an electric motor 344, that may be configured to move roll carriage or elevator 302 and packaging material dispenser 306 vertically relative to load 310. In addition, similar to wrapping apparatus 100, wrapping apparatus 300 may include various sensors, as well as additional components used in connection with other aspects of a wrapping operation, e.g., a clamping device 359 may be used to grip the leading end of packaging material 308 between cycles.
Each of wrapping apparatus 200 of
Those skilled in the art will recognize that the example environments illustrated in
During a typical wrapping operation, a clamping device, e.g., as known in the art, is used to position a leading edge of the packaging material on the load such that when relative rotation between the load and the packaging material dispenser is initiated, the packaging material will be dispensed from the packaging material dispenser and wrapped around the load. In addition, where prestretching is used, the packaging material is stretched prior to being conveyed to the load. During a main portion of a wrapping cycle, the dispense rate of the packaging material is controlled during the relative rotation between the load and the packaging material, and a lift assembly controls the position, e.g., the height or elevation, of the web of packaging material engaging the load so that the packaging material is wrapped in a spiral manner around the sides of the load from the base or bottom of the load to the top. Multiple layers of packaging material may be wrapped around the load over multiple passes to increase overall containment force, and once the desired amount of packaging material is dispensed, the packaging material is severed to complete the wrap.
In addition, as noted above, during a wrapping operation, the position of the web of packaging material may be controlled to wrap the load in a spiral manner.
A packaging material dispenser 610 is mounted to a roll carriage or elevator 612 that is configured for movement along an axis 614 by a lift mechanism 616. Packaging material dispenser 610 supports a roll 618 of packaging material, which during a wrapping operation includes a web 620 extending between packaging material dispenser 610 and load 606.
Axis 614 is generally parallel to an axis about which packaging material is wrapped around load 606, e.g., axis 608, and movement of elevator 612, and thus web 620, along axis 614 during a wrapping operation enables packaging material to be wrapped spirally around the load. It will be appreciated, however, that axis 614 need not be parallel to axis 608 in some embodiments, and in such embodiments, a change in elevation of web 620 parallel to axis 608 may represent only a component of the movement of elevator 612 along axis 614 that is parallel to axis 608. It will be appreciated that a roll carriage or elevator, in this regard, may be considered to include any structure on a wrapping machine (e.g., a turntable-type, rotating ring-type or rotating arm-type) that is capable of controllably changing the elevation of a packaging material dispenser coupled thereto, and thereby effectively changing the elevation of a web of packaging material dispensed by the packaging material dispenser.
The position of packaging material dispenser 610 may be sensed using a sensing device (not shown in
Moreover, in the illustrated embodiments discussed hereinafter, axis 608 is vertically oriented such that elevator 612 moves substantially vertically in a direction corresponding to a height dimension of the load. In some embodiments, however, such as in connection with a horizontal ring-type wrapping apparatus, the axis of rotation may not be vertically oriented. As such, while reference may be made hereinafter to directions or positions such as “top,” “bottom,” “up,” “down,” “elevation,” etc., one of ordinary skill in the art will appreciate that such nomenclature is used merely for convenience, and the invention is not limited to use with a vertical axis of rotation.
Control of the position of elevator 612, as well as of the other drive systems in wrapping apparatus 600, is provided by a controller 622, the details of which are discussed in further detail below.
As will become more apparent below, automatic load profiling in the illustrated embodiments may be used to generate a load profile for a load, generally representing a collection of properties of the load that may be utilized in the control of a stretch wrapping machine to wrap the load. In addition, in some embodiments, a load profile may be configured as a data structure and may be stored in a database or other suitable storage, and may be created using a controller or computer system, imported from an external system, exported to an external system, retrieved from a storage device, etc. In other embodiments, however, a load profile may simply be a collection of properties for a load collected prior to a wrapping operation performed on the load using one or more of upstream sensor data, sensor data collected at a wrapping location prior to and/or during a wrapping operation, data retrieved from a database or external source or data input by an operator, and in some embodiments, the collected properties may be discarded after the load is wrapped.
The properties that may be incorporated into a load profile may vary in different embodiments, and sensor inputs from a number of different types of sensors may be used in order to determine a number of different types of properties of a load for inclusion in a load profile. In particular, a load profile may include various load dimensions such as overall height or elevation, length and/or width for a load, as well as dimensions of different portions of a load, e.g., of a main body, an inboard portion, an inboard product, a pallet, etc. Further, in some embodiments, dimensions of individual products, cartons, packages, etc. may also be included in a load profile. The dimensions may be based upon distances along regular Cartesian axes, e.g., heights or elevations, widths, lengths in the case of cuboid-shaped loads or load portions, as well as based on other distances as may be appropriate for non-cuboid-shaped loads or load portions, e.g., circumferences, perimeters, diameters, chord lengths, etc. In addition, in some embodiments, the determination of various dimensions of a load may be based upon sensing the locations of one or more surfaces of a load in a three-dimensional space, e.g., by sensing the locations of one or more points on such surfaces, and as such, in some embodiments, a load profile may include locations of one or more points, surfaces, edges, corners, etc. of a load. Still further, dimensions may be represented as relative dimensions (e.g., “short”, “normal”, “long”, etc.), and dimensions may also be determined as averages, medians, etc. of multiple data points.
Further, in some embodiments a load profile may include a surface model for the load. A surface model, in this regard, may be considered to include a collection of data that models one or more surfaces of the load. A surface may be modeled, for example, using one or more points defining the surface, by one or more dimensions defining the surface, etc.
Further, in some embodiments, a surface model may identify a top surface topography that may be used, for example, to identify various irregular aspects of a particular load. A top surface topography may, for example, define a plurality of elevations for the load, generally taken at a plurality of locations on one or more top surfaces defined on the load. As an example, assuming a substantially vertical axis of rotation and a Cartesian (x, y, z) coordinate system, height or elevation may be defined along the z-axis, and the plurality of locations may be defined with different coordinates along the x and y axes. The height or elevation may be taken relative to various planes that are perpendicular to the axis of rotation, e.g., a floor, a load support upon which a load has been placed, a top of a pallet, a predetermined reference elevation on the load (e.g., a top surface of a main body), or even a reference elevation located at a higher elevation than the load (e.g., the position of an overhead sensor).
As will become more apparent below, a surface model may be used, for example, to define an inboard portion of a load or a ragged topography for a top surface of a load. As such, a surface model in some embodiments may include data such as values representing respective heights/elevations for a main body, an inboard portion, a pallet, etc., or values representing maximum, minimum, average or median heights/elevations therefor. In some embodiments, however, a surface model may include additional data, e.g., heights/elevations at a plurality of locations or surface definitions derived from such points.
In some embodiments, surfaces modeled by a surface model may be assumed to be substantially perpendicular to an axis of rotation, and as such, may be identified simply using a single height or elevation. Thus, for example, a surface model in one embodiment may identify a height or elevation of an inboard load to effectively define a top surface of the inboard portion of a load, along with a height or elevation of a supporting body of a load to effectively define a top surface of the supporting body. In other embodiments, however, the surfaces modeled by a surface model may be defined based upon multiple data values, e.g., multiple points.
Further, in some embodiments, a load profile may include various parameters associated with the weight of the load and/or any components of the load. A weight parameter, for example, may be the actual weight of a load or a component of a load, or may simply be a relative weight such as a categorization of the load as “heavy” or “light” or some other collection of ranges. In addition, a weight parameter may be based upon a single weight measurement or multiple weight measurements (e.g., to calculate an average or to select a maximum measurement), and a weight parameter may include the weight of the pallet or may have the weight of the pallet removed therefrom.
In addition, in some embodiments a load profile may also include one or more density parameters associated with a density of the load. Density, in this regard, may be considered to refer to a general relationship between the size of a load and its weight that is indicative of the relative stability of the load during wrapping. It will be appreciated, for example, that a relatively short load of relatively heavy products will likely be more stable than a relatively tall load of relatively light products, and as such, relative stability of a load may be based on a relationship between the size of the load and its weight.
A density parameter may be based upon the ratio of actual volume and the actual weight for a load in some embodiments, while in other embodiments, other values that are indicative of a relative density of a load may be used. For example, in some embodiments, a load may be assumed to be cuboid in shape regardless of its actual top surface topography, and a density parameter may be based upon a volume approximation calculated from the product of the overall height, length and width of the load. In other embodiments, no volume may be calculated, and an assumption may be made that all loads have similar lengths and widths, such that a height or elevation of a load and/or one or more components of the load may combined with a weight parameter in order to determine the density parameter. In still other embodiments, the size and/or the weight may be categorized into various ranges (e.g., “short” for less than H1 inches, “medium” for between H1 and H2 inches and “tall” for more than H2 inches and/or “light” for less than X1 pounds, “normal” for between X1 and X2 pounds, and “heavy” for more than X2 pounds), and a relative density parameter may be determined based upon these categorizations (e.g., “tall and light”, “short and heavy”, etc.).
A stability parameter may also be used in a load profile in some embodiments. In some embodiments, for example, a stability parameter associated with relative stability may be derived from a density parameter as discussed above. In other embodiments, stability may be sensed using a sensor. For example, in one embodiment a load may be subjected to a rocking motion through movement of a load support and force resolutions thereafter may be recorded (e.g., using one or more load cells coupled to the load support) to detect the amount of movement induced in the load. In still another embodiment, a rocking motion may be induced and one or more image sensors may detect an amount of movement induced in a top portion of the load.
Another load property that may be used in a load profile in some embodiments is a verticality property, representing the verticality of one or more sides of the load. The verticality may be used, for example, to detect a load that is leaning, a load that is twisted about the axis of rotation, a load that is irregular from layer to layer, etc. The verticality property may represent the degree to which a load is irregular, e.g., a load where at least some of the sides of the load are not substantially vertical and/or are not substantially planar in profile. An irregular load may result, for example, from differently-sized articles being placed in each layer, from adjacent layers of same-sized articles not being placed in perfect alignment, from the load leaning due to a weight imbalance, or from shifting of the load while on the conveyor or otherwise during movement of the load.
Verticality/irregularity may be detected, for example, based upon a surface model of the main body of a load, based on distance measurements taken from a sensor that changes in elevation with a packaging material dispenser, based upon distance measurements taken from a fixed sensor (e.g., as shown in
It will also be appreciated that in some embodiments, one or more load properties may be sensed by a sensor mounted to a wrapping machine or otherwise positioned to sense the load when the load is placed in a wrapping position, and further, in some embodiments, one or more load properties may be sensed by sensors positioned to sense the load prior to the load being placed in a wrapping position (e.g., while the load is on a conveyor, a pallet truck, or a lift truck, or while the load is positioned in a palletizer or other upstream handling equipment. Further still in some embodiments, one or more load properties may be based upon operator input, based on data stored in a database, or otherwise determined without the use of a sensor (e.g., if standard 40×48 pallets are used, properties such as pallet length, width, height and/or weight could be entered by an operator, stored in a database, or hard-coded into a control program).
The sensors used to sense various load properties for incorporation in a load profile may vary in different embodiments.
In some instances, one sensor may be used to directly determine the height of an inboard portion of a load as well as to determine the height of a load not having an inboard portion. In other instances, however, it may be desirable to use a different sensor to sense the height of an inboard portion of a load, e.g., any of sensors 632, 634 or 636 of
Other types of sensors may be used to measure various properties of the load, e.g., other types of sensors capable of sensing dimensions and/or surfaces such as proximity sensors, laser distance sensors, ultrasonic distance sensors, digital cameras, range imaging sensors, three-dimensional scanning sensors, light curtains, sensor arrays, etc., as well as other types of sensors capable of sensing weight such as load cells, conveyor-mounted scales or load cells, etc. Other sensors not explicitly mentioned herein but suitable for use in some embodiments will be appreciated by those of ordinary skill in the art having the benefit of the instant disclosure. Further, it will be appreciated that sensing or measuring of a load may also be performed prior to the load being placed or conveyed to a wrapping location, e.g., while the load is being conveyed to a wrapping apparatus.
In some embodiments, an off-axis sensor may be used to detect the height of a supporting body and thereby enable the height of an inboard portion of a load to be separately determined by an on-axis sensor. The term “off-axis”, in this regard, refers to a sensing direction of a sensor that does not intersect the axis of rotation between a load and a packaging material dispenser. With reference to
By directing off-axis sensor 708 offset from axis of rotation 712, off-axis sensor 708 may detect the presence of main body 702 without detecting inboard portion 704. In some embodiments, for example, off-axis sensor 708 may be oriented to detect main body 702 of load 700 about 10″ inside of a corner of main body 702 when main body 702 is oriented in the position illustrated in
In addition, in some embodiments, it may be desirable to sense the heights of the supporting body and/or inboard portion of the load while the load is stationary (i.e., when there is no relative rotation between the load and a packaging material dispenser). In one embodiment, for example, a wrap cycle may begin with a roll carriage or elevator rising from a bottom position while no relative rotation is performed between the load and the packaging material dispenser. During this process, off-axis sensor 708 scans for the top of main body 702 while on-axis sensor 710 scans for the top of inboard portion 704.
In still other embodiments, determination of the presence and/or dimensions of an inboard portion of a load may be made using one or more sensors capable of automatically determining a three-dimensional profile of at least the top of a load. Various types of cameras, range imaging sensors, three-dimensional scanning sensors, etc. may be used, for example, to determine a complete profile of the top of a load, including the topography of the top of the load as well as the overall length and width of a main body of the load. In some embodiments, other types of information related to a three-dimensional profile may also be sensed and/or derived from a three-dimensional profile, e.g., the presence/absence of an inboard portion, the height of the inboard portion and/or a supporting body of the load, the dimensions, orientation and/or position of an inboard portion and/or any individual cartons or products making up an inboard portion, etc.
It will be appreciated from
Returning to
Now turning to
In some embodiments, load profile manager block 642 may be controlled by wrap control block 652 to analyze a load positioned in a wrapping position prior to wrapping such that a load profile may be generated for access by wrap control block 652 to generate or modify a suitable wrap profile to be used when wrapping the load. In some embodiments, load profiles may be stored in a database or other data store and accessed in response to operator input or input from an external device. In still other embodiments, load profile manager block 642 may analyze a load prior to the load being positioned in a wrapping position, and in some instances, load profile manager block 642 may be implemented within a device that is external to a wrapping apparatus, and in some embodiments some of all of the data in a load profile may be input by an operator, retrieved from a database, or otherwise received from non-sensor data.
Wrap control block 652 is additionally coupled to a wrap profile manager block 654 and a packaging material profile manager block 656, which respectively manage a plurality of wrap profiles 658 and packaging material profiles 660.
Each wrap profile 658 stores a plurality of parameters, including, for example, a containment force parameter 662, a wrap force (or payout percentage) parameter 664, and a layer parameter 666. In addition, each wrap profile 658 may include a name parameter providing a name or other identifier for the profile. In addition, a wrap profile may include additional parameters, collectively illustrated as advanced parameters 670, that may be used to specify additional instructions for wrapping a load. Additional parameters may include, for example, an amount of overlap, number of top/bottom wraps, wrap force variations for different areas of the load, rotation speeds for different areas of the load and/or times during the wrap cycle, band positions and wrap counts, a rotational data shift to apply during wrapping, whether a load is inboard of a pallet, etc.
In addition, in some embodiments the advanced parameters 670 may also include indicators as to whether a top layer containment operation should be performed, and if so, what type of operation and/or any parameters controlling how the operation should be performed (e.g., number of revolutions, how far inward the packaging material should pass from each corner, etc.). Some or all of these parameters may be input by an operator in some embodiments, while in some embodiments one or more of these parameters may be automatically selected or generated based upon automatic load profiling.
A packaging material profile 660 may include a number of packaging material-related attributes and/or parameters, including, for example, an incremental containment force/revolution attribute 672 (which may be represented, for example, by a slope attribute and a force attribute at a specified wrap force), a weight attribute 674, a wrap force limit attribute 676, and a width attribute 678. In addition, a packaging material profile may include additional information such as manufacturer and/or model attributes 680, as well as a name attribute 682 that may be used to identify the profile. Other attributes, such as cost or price attributes, roll length attributes, prestretch attributes, or other attributes characterizing the packaging material, may also be included.
Each profile manager 654, 656 supports the selection and management of profiles in response to input data, e.g., as entered by a user or operator of the wrapping apparatus. For example, each profile manager may receive user input 684, 686 to create a new profile, as well as user input 688, 690 to select a previously-created profile. Additional user input, e.g., to modify or delete a profile, duplicate a profile, etc. may also be supported. Furthermore, it will be appreciated that user input may be received in a number of manners consistent with the invention, e.g., via a touchscreen, via hard buttons, via a keyboard, via a graphical user interface, via a text user interface, via a computer or controller coupled to the wrapping apparatus over a wired or wireless network, etc. Similar functionality may also be supported for load profile manager 642 in some embodiments.
In addition, load, wrap and/or packaging material profiles may be stored in a database or other suitable storage, and may be created using control system 640, imported from an external system, exported to an external system, retrieved from a storage device, etc. In some instances, for example, packaging material profiles may be provided by packaging material manufacturers or distributors, or by a repository of packaging material profiles, which may be local or remote to the wrapping apparatus. Alternatively, packaging material profiles may be generated via testing.
A load wrapping operation using control system 640 may be initiated, for example, upon selection of a wrap profile 658 and a packaging material profile 660, as well upon selection or generation of a load profile 646, e.g., based upon sensing of the load using one or more sensors 644. Doing so results in initiation of a wrapping operation through control of a packaging material drive system 692, rotational drive system 694, and lift drive system 696. Further, in some embodiments where top layer containment operations are performed, a roping mechanism 698 may also be controlled. Additional controllable components, e.g., clamps, heat sealers, etc., may also be controlled at appropriate points in a wrap cycle.
Wrap profile manager 654 may also include functionality for automatically calculating one or more parameters in a wrap profile based upon a load profile and/or one or more other wrap profile parameters. For example, wrap profile manager 654 may be configured to select a top layer containment operation for a wrap profile and/or may select a load containment force requirement for the wrap profile based in part on a density parameter in the load profile.
Furthermore, wrap profile manager 654 may include functionality for automatically calculating one or more parameters in a wrap profile based upon a selected packaging material profile and/or one or more other wrap profile parameters. For example, wrap profile manager 654 may be configured to calculate a layer parameter and/or a wrap force parameter for a wrap profile based upon the load containment force requirement for the wrap profile and the packaging material attributes in a selected packaging material profile. In addition, in response to modification of a wrap profile parameter and/or selection of a different packaging material profile, wrap profile manager 654 may automatically update one or more wrap profile parameters.
Now turning to
Next, in block 804, one or more dimensions of the load may be determined from the surface model, and in block 806, a weight parameter may be determined for the load, e.g., based upon a sensed weight from a scale, based upon an input from an upstream weight sensor, based upon a relative weight (e.g., light, normal, heavy) etc. Next, in block 808, a density parameter is determined for the load based upon the determined dimension(s) and weight parameter, and in block 810, a load stability is determined from the density parameter, e.g., to characterize the load as stable or unstable. Then, based upon the aforementioned determined properties, the load profile is generated and stored in the control system in block 812.
Returning to block 802, a surface model may be generated in a number of manners consistent with the invention. For example, as illustrated at 820 in
Next, in block 828, an attempt may also be made to determine if a load has a top or slip sheet and/or if a load has an easily deformable top layer. As an example, if the sensor data is collected from an image-based sensor, image data may be analyzed to attempt to identify shapes, colors, reflectivity, markings, or other visual structures to determine whether a top sheet or a slip sheet has been placed on the top of the load. A slip sheet, for example, may be formed of cardboard and may have both a characteristic brown color and a characteristic rectangular size and shape that may be readily detected through image analysis. In addition, in some embodiments image analysis may be performed to attempt to determine if a top layer of a load is easily deformable or crushable, e.g., by attempting to detect whether products in the top layer are in cartons or not, or by attempting to detect characteristic shapes and/or colors of easily deformable products such as paper towels, beverage bottles, etc. In other embodiments, however, block 828 may be omitted, and no attempt may be made to sense the presence of a top/slip sheet and/or easily deformable top layer.
Now turning to
Then, in block 836, wrap force and/or minimum layer control parameters may be determined based upon the determined containment force requirement. As discussed in the aforementioned cross-referenced application, for example, the containment force requirement and the properties of the packaging material to be used in the wrapping operation may be used to determine an incremental containment force (ICF) parameter, from which a wrap force parameter and a minimum number of layers parameter may be calculated. Further details regarding the determination of control parameters from containment force, and the control of a wrapping operation based upon containment force, are discussed, for example, in U.S. Patent Application Publication No. 2014/0116006, entitled “ROTATION ANGLE-BASED WRAPPING,” and filed Oct. 25, 2013; U.S. Patent Application Publication No. 2014/0116007, entitled “EFFECTIVE CIRCUMFERENCE-BASED WRAPPING,” and filed Oct. 25, 2013; U.S. Patent Application Publication No. 2014/0116008, entitled “CORNER GEOMETRY-BASED WRAPPING,” and filed Oct. 25, 2013; U.S. Patent Application Publication No. 2014/0223863, entitled “PACKAGING MATERIAL PROFILING FOR CONTAINMENT FORCE-BASED WRAPPING,” and filed Feb. 13, 2014; U.S. Patent Application Publication No. 2014/0223864, entitled “CONTAINMENT FORCE-BASED WRAPPING,” and filed Feb. 13, 2014; and U.S. Patent Application Publication No. 2015/0197360, entitled “DYNAMIC ADJUSTMENT OF WRAP FORCE PARAMETER RESPONSIVE TO MONITORED WRAP FORCE AND/OR FOR FILM BREAK REDUCTION,” and filed Jan. 14, 2015, all of which are incorporated herein by reference in their entirety.
It will be appreciated that in other embodiments, no intermediate stability type may be stored in a load profile and/or used to determine a containment force requirement for a load, such that the density parameter may be used to directly determine a containment force requirement for a load. Further, in other embodiments, a density parameter may be used to control other parameters used in other types of wrapping machines given that the density may be considered to represent a relative stability of a load in many situations. For example, a density parameter may be used to control wrap force, tension, payout percentage, carriage speed, rotation speed, conveyor speed and/or other types of control parameters that may be used in other types of wrapping machines.
Next, in block 838, a determination may also be made as to whether a load is inboard of a pallet, and if so, a distance that the load is inboard. Such a determination may be based, for example, on a comparison of the cross-sectional dimensions of a pallet and a main body of a load, as determined from the surface model. The presence of an inboard load on a pallet may be used to decrease a wrap force used while wrapping around the pallet and/or to increase a number of layers applied proximate a pallet to reduce the risk of packaging material breaks occurring while wrapping packaging material around the pallet.
Next, in block 840, a determination is made as to whether the load has a nonstandard top layer, and if so, a top layer containment operation is activated, and optionally, one or more control parameters for the top layer containment operation are generated. Various types of top layer containment operations are disclosed, for example, in U.S. Provisional Application No. 62/145,789 filed on Apr. 10, 2015, U.S. Provisional Patent Application Ser. No. 62/232,906 filed on Sep. 25, 2015, and PCT Application No. PCT/US2016/026723 filed on Apr. 8, 2016, each of which is incorporated by reference herein.
Next, in block 842, the determined control parameters are stored in a wrap profile, and block 844 determines whether to wait for operator changes to be made to the wrap profile. In some embodiments, for example, automatic load profiling may not incorporate any operator input and/or may not be initiated and/or completed until after a wrapping cycle has been initiated (e.g., activation of a top layer containment operation may not be performed until a sensor mounted on a packaging material dispenser carriage has moved to a position where an inboard load can be detected), so after control parameters have been automatically determined, block 844 may pass control directly to block 846 to wrap the load based upon the wrap profile. In other embodiments, however, the control parameters stored in the wrap profile may be accessible by an operator and may be modified if desired, and the operator may be required to manually initiate a wrapping operation (e.g., by pressing a start button). In such instances, therefore, block 844 may pass control to block 848 to modify the wrap profile based upon operator input, and then to block 846 to wrap the load. It will be appreciated that due to the fact that automatic load profiling may be performed based upon sensor data collected upstream of a wrapping machine, at a wrapping position and/or during a wrapping cycle, and that at least some of the load properties for a load may be based on operator input and/or retrieved from a database or external device, the types of operator interaction (if any) that may be performed between generating control parameters based upon automatic load profiling and actually wrapping a load using those control parameters may vary substantially in different embodiments.
Block 842 may, in some embodiments, configure a wrap profile e.g., by creating a new wrap profile or modifying an existing wrap profile. In other embodiments, block 842 may select from among preexisting wrap profiles based upon the load profile.
If above the threshold, block 856 passes control to block 858 to activate a “U wrap” top layer containment operation, and if not, block 856 passes control to block 860 to activate a “cross wrap” top layer containment operation, the details of which will be discussed in greater detail below.
Returning to block 854, if no inboard portion or ragged topography is detected, block 854 passes control to block 862 to determine if the load has a top or slip sheet and/or if the load has an easily deformable top layer. Block 862 in some embodiments may determine these nonstandard top layers automatically based upon sensor data, as discussed above in connection with block 828 of
If either of such nonstandard top layer is determined to be present on the load, block 864 passes control to block 860 to activate the cross wrap top layer containment operation. Otherwise, block 864 passes control to block 866 to deactivate all top layer containment operations, such that the load will be wrapped using a traditional, spiral wrapping operation with no additional packaging material wrapped over a top surface of the load.
With this cross wrap top layer containment operation, two revolutions of a cross wrap sequence are illustrated, with a first revolution applying packaging material identified at 746. In this revolution, a web of packaging material engages corner C1 of a first pair of opposing corners (C1 and C3), after which the elevation of the web increases such that the web passes inwardly of corner C2. The elevation of the web is then decreased such that the web engages corner C3, after which the elevation of the web increases such that the web passes inwardly of corner C4. The elevation of the web is then decreased such that the web again engages corner C1, with portions of the web of packaging material overlapping or engaging a top surface 736 of main body 726, side surfaces of one or more cartons 734 in top layer 732 and/or top surfaces 738 of cartons 734 in top layer 732. In a second revolution, which may begin 90 degrees, 270 degrees, 450 degrees, etc. after the completion of the first revolution, another cross wrap sequence is performed, but starting at a corner from the other pair of opposing corners (i.e., corner C2 or C4) to apply packaging material identified at 748. Assuming, for example, that the second revolution begins 90 degrees after the first revolution, during the 90 degrees of rotation, the elevation of the web may be held at substantially the same elevation to enable the web to wrap around the side of the load and engage corner C2. Thereafter, the elevation of the web is increased such that the web passes inwardly of corner C3, then the elevation is decreased such that the web engages corner C4, then the elevation of the web is increased such that the web passes inwardly of corner C1, and then the elevation is decreased such that the web again engages corner C2, with portions of the web again overlapping or engaging a top surface 736 of main body 726, side surfaces of one or more cartons 734 in top layer 732 and/or top surfaces 738 of cartons 734 in top layer 732.
With this U wrap top layer containment operation, two revolutions of a U wrap sequence are illustrated, with a first revolution applying packaging material identified at 888. In this revolution, a web of packaging material engages corner C1, after which the elevation of the web increases such that the web passes inwardly of corners C2 and C3 to engage inboard portion 884 within each of quadrants Q2 and Q3. Thereafter, the elevation of the web is decreased such that the web engages corner C4, after which the elevation of the web is maintained at a level such that the web again engages corner C1. In a second revolution, which may begin, for example, 180 degrees after the completion of the first revolution, another U wrap sequence may be performed to apply the packaging material identified at 890, but starting at corner C3. In this revolution, the web engages corner C3, after which the elevation of the web increases such that the web passes inwardly of corners C4 and C1 to engage inboard portion 884 within each of quadrants Q4 and Q1. Thereafter, the elevation of the web is decreased such that the web engages corner C2, after which the elevation of the web is maintained at a level such that the web again engages corner C3.
As discussed in the aforementioned cross-referenced applications, control of the elevation of a web may be based upon movement of an elevator or carriage supporting at least a portion of a packaging material dispenser, engagement of a roping mechanism to fully or partially narrow the web from the top and/or bottom edge, changing the orientation or tilt of the web, and other manners that would be apparent to one of ordinary skill in the art having the benefit of the instant disclosure. Further, the control may be used for functional purposes, e.g., to contain a particular size or type of inboard load or top surface topography, as well as for aesthetic purposes, e.g., to provide a symmetrical wrapping pattern around all four sides of the load.
Furthermore, various control parameters may be used to control the placement of the web for functional and/or aesthetic concerns. For example, control of the elevation of a web to position the web in desired position(s) on a load may be based upon the elevation of the web, the rate of change of the elevation of the web (e.g., the speed of an elevator), the timing of when changes in the elevation of the web occur and/or the separation between corners (e.g., based upon the length (L) and/or width (W) of the load and/or any offset in the load from a center of rotation). For example, the timing may be based upon a sensed rotational angle between a packaging material dispenser and a load (e.g., using a rotary encoder or other angle sensor), or in some embodiments, may be based upon a timer that is triggered at a known rotational position (e.g., a home rotational position) and that is based upon a known rate of rotation (e.g., in RPM). Further, trigonometric principles may be applied to determine, based the elevation of the web after engaging a corner and the desired point of contact between adjacent corners, what the elevation of the web needs to be and when the web needs to reach the desired elevation. It will be appreciated that due to the tackiness of packaging material, a portion of a web that engages a corner will generally adhere to the corner and retain the elevation and angle at which it was applied. Likewise, a portion of a web that wraps over an edge between a side and the top surface of the load will also generally adhere to the side of the load and thereby retain the same elevation and angle at which it was applied. As such, control over the elevation of the web at each of these points of contact with the corner and the edge (as well as corresponding control of the elevation when returning to engage a subsequent corner) may be used to pass the web inwardly of the subsequent corner to a controlled amount.
Further, in some embodiments it may also be desirable to control a wrap force or tension applied to a web of packaging material during a top layer containment operation to optimize containment and reduce the risk of packaging material breaks. For example, it should be appreciated that when a web is increasing in elevation in conjunction with relative rotation, the effective demand of the load increases above the demand during the main portion of a wrapping cycle, and as such, decreasing the wrap force or tension applied to the web of packaging material during an elevation increase in association with passing inwardly of a corner may offset the increased demand. Likewise, increasing the wrap force or tension applied to the web of packaging material during an elevation decrease after passing inwardly of a corner may offset a decrease in demand occurring due to the lowering of the elevation of the web. In some embodiments, for example, it may be desirable to temporarily increase and/or decrease a wrap force relative to a wrap force parameter that is used to control the wrap force during the main portion of a wrapping cycle. It will also be appreciated that control over a wrap force or tension may also be handled by changing a dispense rate of a packaging material dispenser, as dispense rate is generally inversely proportional to the tension in a web of packaging material during a wrapping operation.
Now turning to
After the density parameter is determined, block 908 determines wrap force and/or minimum layer control parameters based on the density parameter, and in block 910 the load is wrapped using the determined control parameters. As noted above, the control parameters that may be controlled may vary based upon the type of wrapping machine and wrapping technology employed. Further, it may be seen in this figure that the load may in some embodiments be wrapped in a fully automated fashion and without operator input.
Block 922 may first determine from the surface model whether a load has an inboard portion and/or ragged topography, i.e., whether the load includes an incomplete top layer that is substantially inboard of a main body of a load, whether the load includes a product that is substantially inboard of a pallet, or whether the load has a top layer with varying elevations, e.g., in the manner discussed above in connection with
If either of such nonstandard top layer is determined to be present on the load, block 934 passes control to block 930 to activate the cross wrap top layer containment operation. Otherwise, block 934 passes control to block 936 to deactivate all top layer containment operations, such that the load will be wrapped using a traditional, spiral wrapping operation with no additional packaging material wrapped over a top surface of the load. Upon completion of any of blocks 928, 930 and 936, control passes to block 938 to continue wrapping the load using the determined control parameters, and performing any activated top layer containment operation at an appropriate point in the wrapping cycle.
In addition, it may be seen that the bottom five layers of load 940 are not perfectly aligned, such that the main body 946 does not have substantially planar vertical sides. As such, load 940 may be considered to be an irregular load.
Load 940 may be conveyed to a wrapping machine on a conveyor 950, and an overhead distance sensor 952 may be positioned to sense a distance to the nearest surface opposing the sensor along a generally vertical axis as load 940 is conveyed past the sensor, and to generate distance data representative of such distance. In addition, a weight sensor 954, e.g., a load cell mounted to a side rail of the conveyor, may be used to generate weight data indicative of the weight of the load. It will be appreciated that while distance sensor 952 and weight sensor 954 may respectively generate actual distances and weights, in some embodiments, only relative distances and/or relative weights may be generated. For example, weight sensor 954 may only generate a signal that is proportional to weight such that the signal may be used to determine whether a load is within one of a plurality of weight categories such as “very light,” “light,” “normal,” “heavy,” and “very heavy,” or other suitable ranges.
As load 940 is conveyed along conveyor 950, distance sensor 952 collects distance data that may be associated with a time stamp, such that with a known conveyor speed, the time may be converted to a length or distance in the direction along which the load is conveyed by the conveyor. As shown in
In some embodiments, for example, detection of a change in distance sensed by sensor 952 from the distance to the conveyor surface (dc) may trigger data collection over a sample window until the distance sensed by sensor 952 returns to the distance to the conveyor surface, and distance data points may be collected at preset intervals. In some embodiments, only the data points corresponding to changes in detected distances may be retained, such that the load may be characterized by the distances detected at the times corresponding to the detected changes. In addition, in some embodiments, during this sample window one or more weight sensor data points may be collected to determine a weight parameter for the load. The weight parameter may be determined from a single data point, or from multiple data points (e.g., via averaging, via selecting the maximum data point, etc.)
Furthermore, in some embodiments it may be desirable to analyze both the leading and trailing sides of the load to detect irregularity and/or how far inboard a main body of a load is on a pallet. As shown in
Now turning to
Next, in block 968, a stability of the load may be determined from the weight parameter and the total height of the load, and then in block 970, a containment force requirement for the load may be determined from the determined stability. For example, in some embodiments, based on the height and the weight parameter, a density parameter representing stability may be calculated (e.g., as the ratio of the weight parameter to height), and the density parameter may be mapped to one of a plurality of containment force requirements, e.g., using a lookup table. In other embodiments, different load stability types may be defined such as a light stable load type, a light unstable load type, a heavy stable load type, and a heavy unstable load type, with each type associated with a containment force requirement, and one of the load stability types may be selected based upon the weight parameter and the height. In still other embodiments, a formula may be used to select a load stability type or directly calculate a containment force requirement from a height and weight parameter. Such a formula may be determined empirically in some embodiments based upon testing of loads with different height and weight combinations. Other variations such as those discussed above may also be used in other embodiments.
Based upon the determined containment force requirement, block 972 then calculates a wrap force and minimum layer control parameters for use in wrapping the load, e.g., in any of the manners disclosed in the aforementioned U.S. Patent Application Publication No. 2014/0223864. The control parameters may be stored in a wrap profile, which in some embodiments may be stored for later access and/or modification by an operator, while in other embodiments may be used to wrap the load with no operator input.
Blocks 974, 976 and 978 next test for three different special circumstances that may be used to trigger a modification of the wrap profile prior to wrapping the load in block 980. If none of these circumstances are detected, blocks 974, 976 and 978 pass control directly to block 980 to wrap the load using the determined control parameters in the wrap profile.
Block 974 determines whether the load is an irregular load, e.g., based upon the detection of a non-vertical and/or non-planar side of the load. It will be appreciated that if the load is irregular, greater fluctuations in demand and effective girth may occur during wrapping, resulting in an increased risk of packaging material breaks. As such, it may be desirable when an irregular load is detected in block 974 to pass control to block 982 to reduce the wrap force control parameter, e.g., by a fixed percentage or alternatively by a percentage that varies based upon the amount of irregularity detected in the load. In addition, based upon the reduction in the wrap force control parameter, one or more layers may be added to compensate for the corresponding decrease in containment force applied to the load, such that the combination of the wrap force parameter and the layer parameter continues to meet the containment force requirement for the load.
Block 976 determines whether the load is an inboard load, e.g., based upon detection of an inboard length (LI) above a threshold. It will be appreciated that if the load is inboard to the pallet, the girth of the pallet is larger than that of the load, so a wrap around the pallet may have a higher risk of tearing the packaging material at the corners of the pallet due to the higher wrap force encountered at those corners. As such, it may be desirable when an inboard load is detected in block 976 to pass control to block 984 to activate an inboard load containment operation in the wrap profile to reduce the wrap force when wrapping around the pallet and/or increase the number of layers around or near the pallet to account for the different girths of the pallet and the load. For example, it may be desirable for a moderately inboard load (e.g., between about 1-3 inches) to activate an inboard load containment operation that reduces the wrap force parameter by a fixed percentage when wrapping around the pallet, and for an extremely inboard load (e.g., greater than about 3 inches) to activate an inboard load containment operation that reduces the wrap force parameter by the same or additional amount when wrapping around the pallet, coupled with applying an additional band of packaging material around the load just above the pallet (and generally using the wrap force control parameter used to wrap the rest of the load).
Block 978 determines whether the load has a nonstandard top layer, e.g., based upon detection of a top layer that is inboard of a main body of the load. If so, block 978 passes control to block 986 to activate an appropriate top layer containment operation (e.g., to select a U wrap or cross wrap sequence based upon a height of the top layer of the load).
Blocks 982, 984 and 986 may each therefore modify the wrap profile to be used for wrapping the load, e.g., by modifying one or more control parameters and/or activating a particular operation during wrapping. Upon completion of any of blocks 982, 984 or 986, control passes to block 980 to wrap the load using the wrap profile using the modifications made thereto.
It will be appreciated that any of the circumstances detected in blocks 974, 976 and 978 may be omitted in some embodiments. For example, in some embodiments, detection of nonstandard top layers may be omitted such that only irregular loads and inboard loads are the only special circumstances detected prior to wrapping.
Now turning to
It will be appreciated that load stability may be affected by a number of factors related to the dimensions and/or contents of a load. For example, load stability may be impacted in some instances by the footprints or dimensions of the packages or cases in a load relative to the overall height of the load. Load stability may also be impacted by load contents, e.g., partially-filled liquid containers, springy or compressible type products (e.g., diapers vs. bags of flour), etc. Load stability may also be impacted by the amount of friction between layers, the use of interleaving sheets between layers, the overall height of the pallet supporting the load, etc.
To sense load stability in some embodiments, a load may be subjected to a force, impulse, sudden change in momentum or other disturbance so that the reaction of the load thereto can be sensed. In some embodiments, for example, a load may be shaken, tilted, impacted or pushed and the response of the load measured in response thereto. The response, for example, may be based upon movement of the load over time, changes in rocking forces over time, etc.
In some embodiments, for example, a load may be conveyed to a wrapping machine on a conveyor, and the reaction of the load to starting or stopping the conveyor may be monitored. As such, in some embodiments, the disturbance being monitored does not need to be separately induced, or require the use of dedicated machinery. In addition, where a turntable is used, sudden starting or stopping of a turntable may be used to disturb the load. In other embodiments, specific operations and/or components may be used to induce a disturbance. For example, it may be desirable in some embodiments to “push” or impact the side of a load to induce lateral rocking of the load, to “tip”, lift or tilt a conveyor or other load support to rock the load, or to vibrate or otherwise shake the load through vibration or orbital motion. It will be appreciated that in each of these instances, it may also be desirable to maintain the magnitude of the disturbance of the load below that which causes shifting or displacement of the contents of the load prior to wrapping. In some embodiments, this magnitude may vary depending upon other characteristics of the load (e.g., heavier and/or shorter loads may be subjected to higher magnitude disturbances).
Sensing of the load reaction to a disturbance may also be implemented in a number of manners in different embodiments. For example, as illustrated in
As another example, as shown in
It will be appreciated that any of sensors 1004, 1014 and 1016 may be used separately or in combination in different embodiments, and that different numbers and/or positions of such sensors may be used in different embodiments. Other sensors capable of sensing the reaction of a load to a disturbance may be used in other embodiments as well.
As discussed above, automatic load profiling consistent with the invention may be based upon load stability, optionally in combination with other determined load characteristics.
After the load stability parameter is determined, block 1048 determines wrap force and/or minimum layer control parameters based on the load stability parameter, and in block 1050 the load is wrapped using the determined control parameters. As noted above, the control parameters that may be controlled may vary based upon the type of wrapping machine and wrapping technology employed. Further, it may be seen in this figure that the load may in some embodiments be wrapped in a fully automated fashion and without operator input.
A load stability parameter, similar to other load characteristics describe above, may be numerical, may be based upon a particular dimension or may be dimensionless, or may be simply a category among a plurality of categories. Load stability may be determined in different manners based upon the type of sensor(s) used and optionally other load characteristics. In one example embodiment, sensor data may be evaluated to determine one or more of a maximum value (e.g., the maximum amount of movement detected), a frequency value (e.g., the rate of oscillation of movement), a time or decay-related value (e.g., how quickly load oscillation of movement dissipates), or other values associated with the reaction of a load to a disturbance. Thus, for example, a load that reacts to a disturbance by deforming or moving a small amount and only doing so for a small number of oscillations may be determined to have greater stability than another load that deflects a large amount and/or oscillates for a longer period of time.
Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the present invention. Therefore the invention lies in the claims set forth hereinafter.
| Number | Date | Country | |
|---|---|---|---|
| 62232915 | Sep 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15762501 | Mar 2018 | US |
| Child | 17232932 | US |
