Stretch wrapping machine with film sealing system

Description

Priority

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 367,511, filed July 1, 2022.Field

[0002] The present disclosure relates to stretch-wrapping machines, and more particularly to stretch-wrapping machines that include a film-sealing assembly.Background

[0003] Several types of known stretch-wrapping machines use stretch film to secure loads of goods on pallets. These stretch-wrapping machines include a film carriage to which a replaceable roll of stretch film is mounted. Depending on the type of stretch-wrapping machine, the film carriage rotates relative to the palletized load or the palletized load rotates relative to the film carriage while the film carriage vertically moves relative to the load to wrap the load with the stretch film in a spiral pattern. For instance, a turntable wrapping machine rotates a turntable carrying the palletized load while vertically moving the film carriage to wrap the load with the stretch film. A ring wrapping machine rotates the film carriage on a circular ring that circumscribes the palletized load while vertically moving the film carriage to wrap the load with the stretch film. A rotating arm wrapping machine rotates a cantilevered arm carrying the film carriage around the palletized load while vertically moving the film carriage to wrap the load with the stretch film.

[0004] Once the wrapping process is substantially complete, the film web extending between the load and the film roll on the film carriage is severed, creating a film tail extending from the load. This film tail must be secured to the film already wrapped around the load to prevent the film from unwinding off the load. This securing process may take place before or after the film web is severed to form the film tail. While certain existing stretch-wrapping machines include various mechanisms for securing the film tail, there is a continuing need to simplify and speed up this process to increase throughput.

[0005] EP 3 795 481 A1 relates to a stretch-wrapping machine with self-adjusting pinch rollers configured to reorient themselves to compensate for misalignment relative to their respective pre-stretch rollers. This ensures the pinch roller press the entire width of the film against their respective pre-stretch rollers as the film is drawn through the rollers.

[0006] US 2002 / 0174626 A1 relates to a heat sealing device for sealing layers of plastic film together. The heat sealing device is incorporated into a stretch wrapping apparatus for wrapping a load. The heat sealing device includes a heater element, an air compressor or blower, and a sealing head in fluid communication with the heater element to distribute the heated air. The sealing head is flexible and includes a plurality of convection ports configured to apply heated air to a portion of the packaging material without being completely covered by the packaging material. At least one insulated film contact portion is provided to distance the convection ports from the plastic film.

[0007] EP 0 597 809 A1 relates to a unit for heat-sealing plastic film used to wrap palletized stacks of commodities, wherein the end of a length of stretch film enveloping a pallet is restrained, prior to being heat-sealed, by a gripping mechanism that can be traversed toward and away from the pallet, and is capable of contracting longitudinally in a direction parallel to the plane occupied by the tail end of the film, transversely to the wrapping direction, from a position of engagement in which the gripping surfaces are spaced apart and uniformly in contact with the film across its maximum width, to a position of restraint in which the selfsame surfaces are drawn together, pinching the film to produce a uniform succession of folds and thus narrowing the material to a width that can be accommodated fully by the heat-seal plate.Summary

[0008] Various embodiments of the present disclosure provide a wrapping machine including: a wrapping-machine frame; a guide mounted to the wrapping machine frame; a guide actuator operably connected to the guide to move the guide vertically relative to the wrapping-machine frame; a wrapping assembly mounted to the guide and comprising a film carriage; a wrapping-assembly actuator operably connected to the wrapping assembly to move the wrapping assembly relative to the guide; and a sealing and cutting device mounted to the guide. The sealing and cutting device includes a heating element support, a heating element guard, a heating element positioned between the heating element support and the heating element guard, and movable between a sealing position and a home position to seal two layers of film together, and a clamp facing inwardly toward the heating element and positionable on an opposite side of the two layers of film from the heating element.

[0009] Various embodiments of the present disclosure provide a method of wrapping a load with a wrapping machine, wherein the method includes: positioning the load in a wrapping area of the wrapping machine; wrapping the load using a wrapping assembly mounted to a guide; positioning a sealing-and-cutting device comprising a heating element assembly near the wrapped load; wrapping the load and the heating element assembly with an inner film sealing layer; overlapping at least a portion of the inner film sealing layer with an outer film sealing layer; positioning a clamp against the outer film sealing layer, such that the clamp faces inward toward the load; actuating the sealing-and-cutting device to seal the inner film sealing layer to the outer film sealing layer; and cutting the outer film sealing layer.Brief Description of the Figures

[0010] Figure 1 is a perspective view of one example embodiment of a stretch-wrapping machine of the present disclosure. Figure 2 is a block diagram showing certain components of the stretch-wrapping machine of Figure 1. Figures 3A-3F are diagrammatic cross-sectional views of the load, the film, and the film-sealing assembly of the wrapping machine of Figure 1 undergoing a sealing process. Figure 4 is flowchart showing steps of a wrapping process including a film-sealing process. Detailed Description

[0011] While the systems, devices, and methods described herein may be embodied in various forms, the drawings show and the specification describes certain exemplary and nonlimiting embodiments. Not all of the components shown in the drawings and described in the specification may be required, and certain implementations may include additional, different, or fewer components. Variations in the arrangement and type of the components; the shapes, sizes, and materials of the components; and the manners of connections of the components may be made. Unless otherwise indicated, any directions referred to in the specification reflect the orientations of the components shown in the corresponding drawings and do not limit the scope of the present disclosure. Further, terms that refer to mounting methods, such as mounted, connected, etc., are not intended to be limited to direct mounting methods but should be interpreted broadly to include indirect and operably mounted, connected, and like mounting methods. This specification is intended to be taken as a whole and interpreted in accordance with the principles of the present disclosure and as understood by one of ordinary skill in the art.

[0012] Various embodiments of the present disclosure provide a stretch-wrapping machine with a heating-element assembly configured to seal sealing layers of the film to complete a stretch wrap of a load.

[0013] Figures 1, 2, and 3A-3F show one example embodiment of the stretch-wrapping machine 1 (sometimes referred to herein as the "wrapping machine" for brevity) of the present disclosure. The wrapping machine 1 includes a wrapping-machine frame 10, a circular guide 20, a guide actuator 30, a wrapping assembly 40, a sealing-and-cutting device 100 (not shown in Figures 1 and 2), an operator interface 500, and a controller 600.

[0014] The wrapping-machine frame 10 is formed from multiple tubular and / or solid members (not individually labeled) and configured to support the other components of the wrapping machine 1. The wrapping-machine frame 10 defines a wrapping area within its interior and has an infeed area 10a at which a palletized load (such as a load L on a pallet P) is conveyed (such as via a conveyor C) into the wrapping area for wrapping and an outfeed area 10b at which the palletized load is conveyed (such as via the conveyor C) from the wrapping area after wrapping. The illustrated wrapping-machine frame 10 is merely one example configuration, and any suitable configuration may be employed.

[0015] The circular guide 20 serves as the mount for the wrapping assembly 40 and is movably mounted to the wrapping-machine frame 10 (such as to one or more vertical members of the wrapping-machine frame 10) such that the circular guide 20 is vertically movable relative to the wrapping-machine frame 10 between an upper position and a lower position.

[0016] The guide actuator 30 is operably connected to the circular guide 20 to move the circular guide 20 relative to the wrapping-machine frame 10 between the upper and lower positions. In certain embodiments, the guide actuator 30 includes one or more motors operably connected to the circular guide 20 via one or more belt-and-pulley assemblies to move the circular guide 20 between the upper and lower positions. In other embodiments, the guide actuator 30 includes one or more pneumatic or hydraulic cylinders operably connected to the circular guide 20 to move the circular guide 20 between the upper and lower positions. There are merely examples, and the guide actuator 30 may include any suitable actuator configured to move the circular guide 20 between the upper and lower positions.

[0017] The wrapping assembly 40 is movably mounted to the circular guide 20 such that the wrapping assembly 40 is rotatable relative to the circular guide 20. The wrapping assembly 40 includes a ring-shaped support (not shown), a film carriage (not labeled), and a wrapping-assembly actuator 400 (Figure 2).

[0018] The ring-shaped support serves as the mount for the film carriage and is movably mounted to the circular guide 20 such that the support (and the carriage and other components connected to the support) is rotatable relative to the circular guide 20. In this example embodiment, the support is movably mounted to the circular guide 20 via multiple spaced-apart rollers (not shown) that are connected to the support and positioned on a track (not shown) on the circular guide 20.

[0019] The film carriage is fixedly connected to the support to move with the support (i.e., rotate relative to the circular guide 20 and move vertically relative to the wrapping-machine frame 10). The film carriage is configured to rotatably support a roll of film (such as plastic stretch film). The film carriage can include various components such as but not limited to a film-carriage frame, film-reel supports, one or more idler rollers, one or more pinch-rollers, one or more pre-stretch rollers, and a pre-stretch drive assembly.

[0020] The wrapping-assembly actuator 400 is operably connected to the wrapping assembly 40 to rotate the wrapping assembly 40 relative to the circular guide 20 and the load L. In certain embodiments, the wrapping-assembly actuator 400 includes one or more motors operably connected to the wrapping assembly 40 via one or more belt-and-pulley assemblies to rotate the wrapping assembly 40 relative to the circular guide 20 and the load L. This is merely an example, and the wrapping-assembly actuator 400 can include any suitable actuator configured to rotate the wrapping assembly 40 relative to the circular guide 20 and the load L.

[0021] The sealing-and-cutting device 100 is supported by the wrapping-machine frame 10 and configured to, after the load L has been wrapped, seal two layers of film F together and cut the film F from the film roll to complete the wrapping process. Cutting the film F creates a leading end of the film F for the film roll for use in the next wrapping process. The sealing-and-cutting device 100 can also be configured to hold the leading end after cutting the film F and to connect the leading end to the next load as it is being wrapped.

[0022] As best shown in Figures 3A-3F, the sealing-and-cutting device 100 includes a film-sealing assembly 200 and a cutter (not shown). The film-sealing assembly 200 includes a heating-element assembly 205 and a clamp 240. The heating-element assembly 205 includes a heating element 210, a heating-element support 220, and a heating-element guard 230. The heating-element assembly 205 is vertically movable (relative to the load L) between a home position (an upper position in this illustrated embodiment) and a sealing position (a lower position in this illustrated embodiment). In the home position, the film-sealing assembly is disengaged from the film and the load and positioned to enable the load L to be wrapped without interference by the film-sealing assembly 200. In the sealing position, the heating-element assembly 205 is positioned as shown in Figure 3B to carry out the film-sealing process as described in detail below. The film-sealing assembly 200 can be coupled to the circular guide 20, and / or the wrapping assembly 40, and moved between the upper and lower positions by the sealing and cutting actuators 300. In certain embodiments, the sealing and cutting actuators 300 can be configured to move the film sealing assembly 200, the heating element assembly 205, the clamp 240, and / or one or more components of these assemblies.

[0023] The heating element 210 includes a suitable component configured to melt two overlapping layers of the film F to one another via thermal conduction, convection, or radiation, depending on the embodiment. In this example embodiment, the heating element 210 includes a rotatable roller configured to be heated to a temperature above the melting temperature of the film F via electrical heating (such as but not limited to resistive heating or induction heating). The heating element 210 is positioned between and in this embodiment is rotatable relative to the heating-element support arm 220 and the heating-element guard 230. The heating-element guard 230 can be independently movable relative to the heating-element support arm 220 and the heating element 210. As best illustrated in Figures 3B and 3C, the heating-element guard 230 is movable relative to the heating-element support arm 220 and the heating element 210 between a shielding position at which the heating-element guard 230 shields the heating element 210 from heating and melting the inner and outer film sealing layers FS1 and FS2 (e.g., Figure 3B) and a heating position at which the heating-element guard 230 exposes the heating element 210 to the inner film sealing layer FS1 (e.g., Figure 3C) so the heating element 210 can heat and melt the inner and outer film sealing layers FS1 and FS2. As shown best in Figures 3C-3E, the heating-element support arm 220 is positioned on an interior side (or load side) of the heating element 210, and the heating-element guard 230 is positioned on an exterior side (or sealing side) of the heating element 210. In various other embodiments, the heating element guard is connected to the heating element support and movable therewith. In such embodiments, the bottom of the heating element guard is above the heating element and thus the heating element guard protects the film above and except for at the position or level of the heading element.

[0024] The clamp 240 is movable between a release position and a clamping position. In the release position, the clamp 240 is positioned so the wrapping assembly 40 can wrap the film F around the load L and / or the heating-element support arm 220 and the heating-element guard 230 without interference from the clamp 240. In the clamping position, the clamp 240 is moved toward and into engagement with the outermost film layer (e.g., outer film sealing layer FS2). The clamp 240 can move between the release position and the clamping position via any suitable form of movement, such as sliding, pivoting, rotating, or translating under control of the sealing and cutting actuators 300.

[0025] The operator interface 500 is configured to receive inputs from an operator and, in certain embodiments, to output information to the operator. The operator interface includes one or more input devices configured to receive inputs from the operator. In various embodiments, the one or more input devices include one or more buttons (such as hard or soft keys), one or more switches, and / or a touch panel. In various embodiments, the operator interface 500 includes a display device configured to display information to the operator, such as information about the palletized load, the status of the wrapping operation, or the parameters of the wrapping machine 1. The operator interface may include other output devices instead of or in addition to the display device, such as one or more speakers and / or one or more lights. In certain embodiments, the operator interface 500 is formed as part of the wrapping machine 1 and is, for instance, mounted to the wrapping-machine frame 10. In other embodiments, the operator interface is remote from the wrapping machine 1.

[0026] The controller 600 includes a processing device communicatively connected to a memory device. The processing device may include any suitable processing device such as, but not limited to, a general-purpose processor, a special-purpose processor, a digital-signal processor, one or more microprocessors, one or more microprocessors in association with a digital-signal processor core, one or more application-specific integrated circuits, one or more field-programmable gate array circuits, one or more integrated circuits, and / or a state machine. The memory device may include any suitable memory device such as, but not limited to, read-only memory, random-access memory, one or more digital registers, cache memory, one or more semiconductor memory devices, magnetic media such as integrated hard disks and / or removable memory, magneto-optical media, and / or optical media. The memory device stores instructions executable by the processing device to control operation of the wrapping machine 1 (such as to carry out a wrapping operation, as described below).

[0027] The controller 600 is communicatively and operably connected to the guide actuator 30, the sealing-and-cutting device 100, the sealing and cutting actuators 300, and the wrapping-assembly actuator 400 to control operation of these components in conjunction with the wrapping operation. The controller 600 is communicatively connected to the operator interface 500 to: (1) receive signals from the operator interface 500 that represent inputs received by the operator interface 500; and (2) send signals to the operator interface 500 to cause the operator interface 500 to output (such as to display) information.

[0028] A wrapping process including a film-sealing process for sealing the film to itself after wrapping is shown in Figures 3A-3F and is described with reference to the flow chart shown in Figure 4. Further, Figures 3A-3F illustrate partial cross-sectional views of the right side of the load, so the left side of the load and the film layers wrapped on the left side of the load are not shown.

[0029] As indicated in block 410, the wrapping process includes positioning the load L in the wrapping area. This includes positioning the circular guide 20 in its upper position, and the sealing-and-cutting device 100 holding the leading end of the film F on the roll R. The controller 600 controls the conveyor C to move the load L on the pallet P through the infeed area 10a and into the wrapping area of the wrapping machine 1.

[0030] As indicated in block 420, the wrapping process includes substantially wrapping the load L, as shown in Figure 3A. After the load L on the pallet P reaches the wrapping area, the controller 600 controls the guide actuator 30 to lower the circular guide 20 such that the wrapping assembly 40 is at least partially vertically aligned with part of the load L. The controller 600 controls the sealing-and-cutting device 100 to hold the leading end of the film F against the load L while controlling the wrapping-assembly actuator 400 to rotate the wrapping assembly 40 relative to the circular guide 20 and the load L. The rotation of the wrapping assembly 40 relative to the load L combined with the sealing-and-cutting device 100 holding the leading end of the film F against the load L causes the film F to be drawn off of the roll R, directed through the rollers of the film carriage, and wrapped around the load L.

[0031] Once the film F has been wrapped around the leading end, the controller 600 controls the sealing-and-cutting device 100 to release the leading end and move away from the load L. The controller 600 continues to control the wrapping-assembly actuator 400 to rotate the wrapping assembly 40 while controlling the guide actuator 30 to vertically move the circular guide 20 such that the load L is wrapped with the film F in a spiral pattern. During wrapping the controller 600 controls one or more pre-stretch actuators to rotate one or more pre-stretch rollers to pre-stretch the film F as it is drawn through the rollers.

[0032] Figure 3A illustrates the load L wrapped by one layer of film, labeled as F1. Although the illustrated embodiment shows the load L wrapped by a single layer F1, the load L can be wrapped one, two, or more times by the wrapping assembly 40, and using any suitable pattern, such as a spiral pattern.

[0033] As indicated in block 430, the film sealing process of the wrapping process includes positioning the film-sealing assembly near the load. Figure 3B illustrates the film-sealing assembly 200 positioned near the load L after the load L has been wrapped by the layer of film F1. The film-sealing assembly 200 may be positioned to engage the film layer F1 or may be positioned adjacent to the film layer F1 without making contact. The heating-element guard 230 is in the shielding position or lower position, preventing exposure of any film to the heating element 210.

[0034] As indicated in block 440, the film sealing process of the wrapping process includes wrapping the load L and the film-sealing assembly 200 with an inner film sealing layer and an outer film sealing layer. The inner film sealing layer is illustrated as first film sealing layer FS1 in Figure 3B. Figure 3C illustrates the second film sealing layer FS2 positioned by the wrapping assembly such that it overlaps at least partially with the first film sealing layer FS1. The second film sealing layer FS2 need not extend fully around the load L, and instead may only partially extend around the load such that creates an overlapping section with the first film sealing layer FS1. The overlapping section of the first and second film sealing layers FS1 and FS2 may be positioned such that it is aligned with the film-sealing assembly 200. The first and second film sealing layers FS1 and FS2 may be wrapped such that they are vertically aligned with each other, as shown in Figure 3C.

[0035] As indicated in block 450, the film sealing process of the wrapping process includes positioning the clamp 240 against the outer film sealing layer FS2. Figure 3C illustrates the clamp 240 moved into the clamping position, pressed against the outer film sealing layer FS2. Alternatively, the clamp 240 can be positioned next to or close to the second film sealing layer FS2 without making contact. The heating-element guard 230 is then moved from the shielding position to the heating position to expose the heating element 210 to the first film sealing layer FS1, as shown in Figure 3C.

[0036] As indicated in block 460, the film sealing process of the wrapping process includes actuating the heating element assembly 205 to seal the inner film sealing layer FS1 to the outer film sealing layer FS2. Figures 3D and 3E illustrate the heating element assembly 205 moving from the sealing position toward the home position, and as the heating element assembly 205 moves, the heating element 210 seals the inner film sealing layer FS1 to the outer film sealing layer FS2, creating a sealed layer FS1 / FS2. To seal the layers together, the heating element 210 presses the first and second film sealing layers FS1 and FS2 into the clamp 240, applying heat as the heating element 210 moves upward. As the heating element assembly 205 moves upward, the combined sealed film layer FS1 / FS2 springs back into contact with the film layer F1 wrapped around the load L, due in part to the pre-stretch applied to those portions of the film F. As shown in the Figures, the heating element 210 extends beyond the heating-element guard 230 (i.e., to the right) when the guard 230 is in the heating position. This can be caused by the guard 230 moving upward and to the left when moving to the heating position (i.e., to expose the eating element), or by moving the heating element 210 to the right (i.e., beyond the guard 230) when the guard 230 moves to the heating position. Alternatively, the heating-element guard 230 may not be movable, and may be always positioned in the heating position such that the heating-element 210 is always exposed.

[0037] Figure 3F illustrates the heating element assembly 205 after it has completed is movement to the home position, and film sealing layers FS1 and FS2 sealed together and sprung back onto the film layer F2. At this stage, the clamp 240 may be moved to the release position to enable the wrapped and sealed load L to be removed from the wrapping area.

[0038] As indicated in block 470, the wrapping process includes cutting the outer film sealing layer FS2. Although not shown in Figures 3A-3F, the cutter of the sealing and cutting device 100 may cut the film either during or after the process of sealing. For example, as the heating element assembly 205 moves from the sealing position to the home position and seals layers FS1 and FS2 together, a cutter may simultaneously be moved to cut film layer FS2 (i.e., the outermost layer of film). The cutter may also include a leading edge film holder to hold the cut end of the film, in preparation for wrapping a next load.

Claims

1. A wrapping machine (1) comprising: a wrapping-machine frame (10); a guide (20) mounted to the wrapping machine frame (10); a guide actuator (30) operably connected to the guide (20) to move the guide vertically relative to the wrapping-machine frame (10); a wrapping assembly (40) mounted to the guide (20) and comprising a film carriage; a wrapping-assembly actuator (400) operably connected to the wrapping assembly (40) to move the wrapping assembly (40) relative to the guide (20); and a sealing and cutting device (100) mounted to the guide (20) and comprising: a heating element support (220), a heating element guard (230), a heating element (210) positioned between the heating element support (220) and the heating element guard (230), and movable between a sealing position and a home position to seal two layers of film together, and a clamp (240) facing inwardly toward the heating element (210) and positionable on an opposite side of the two layers of film from the heating element (210).

2. The wrapping machine (1) of claim 1, wherein the heating element support (220) is positioned on a first side of the heating element (210), and the heating element guard (230) is positioned on a second, opposite side of the heating element (210).

3. The wrapping machine (1) of claim 2, wherein the heating element guard (230) is movable between a shielding position and a heating position, wherein in the shielding position the heating element guard (230) prevents the heating element (210) from engaging a first layer of film, and wherein in the heating position the heating element guard (230) enables the heating element (210) to engage the first layer of film.

4. The wrapping machine (1) of claim 1, wherein the clamp (240) is movable between a release position and a clamping position.

5. A method of wrapping a load with a wrapping machine (1), the method comprising: positioning the load in a wrapping area of the wrapping machine (1); wrapping the load using a wrapping assembly (40) mounted to a guide (20); positioning a sealing-and-cutting device (100) comprising a heating element assembly (205) near the wrapped load; wrapping the load and the heating element assembly (205) with an inner film sealing layer (FS1); overlapping at least a portion of the inner film sealing layer (FS1) with an outer film sealing layer (FS2); positioning a clamp (240) against the outer film sealing layer (FS2), such that the clamp (240) faces inward toward the load; actuating the sealing-and-cutting device (100) to seal the inner film sealing layer (FS1) to the outer film sealing layer (FS2); and cutting the outer film sealing layer (FS2).

6. The method of claim 5, wherein the heating element assembly (205) comprises a heating element (210) positioned to face away from the load, a heating element support (220), and a heating element guard (230).

7. The method of claim 6, wherein the heating element guard (230) is movable between a shielding position and a heating position, the method further comprising moving the heating element guard (230) to the heating position to expose the inner film sealing layer (FS1) to the heating element (210).

8. The method of claim 7, further comprising: moving the heating element assembly (205) from a sealing position to a home position while the inner film sealing layer (FS1) is exposed to the heating element (210); and pressing the heating element (210) against the inner film sealing layer (FS1) and toward the clamp (240), to seal the inner film sealing layer (FS1) to the outer film sealing layer (FS2).

9. The method of claim 6, the method further comprising: positioning the heating element assembly (205) such that the heating element support (220) engages an outer layer of film wrapped around the load, and the heating element guard (230) engages the inner film sealing layer (FS1).

10. The method of claim 5, wherein the inner film sealing layer (FS1) and the outer film sealing layer (FS2) are vertically aligned.

11. The method of claim 5, wherein the clamp (240) is positioned against an external surface of the outer film sealing layer (FS2).

12. The method of claim 5, wherein cutting the outer film sealing layer (FS2) occurs at the same time as the sealing-and-cutting device (100) seals the inner film sealing layer (FS1) to the outer film sealing layer (FS2).

13. The method of claim 5, wherein actuating the sealing-and-cutting device (100) to seal the inner film sealing layer (FS1) to the outer film sealing layer (FS2) comprises: exposing the inner film sealing layer (FS1) to a heating element (210) of the heating element assembly (205) such that the heating element (210) contacts the inner film sealing layer (FS1), wherein the heating element (210) faces outward away from the load; and moving the heating element assembly (205) from a sealing position to a home position while maintaining contact between the heating element (210) and the inner film sealing layer (FS1).