Strapping machine with strap pre-feed

Abstract

Various embodiments of the present disclosure provide a strapping system including a frame, a load supporter defining a strapping area, a platen movable toward and away from the load supporter, a platen actuator operably connected to the platen and configured to move the platen toward and away from the load supporter, a strap chute encircling the strapping area, a strapping head, and a controller. The controller is configured to control the platen actuator to begin moving the platen toward a load positioned in the strapping area and, responsive to a strap-feed condition being met based on an applied compressive force the platen applies to the load, control the strapping head to feed strap from a strap supply into and around the strap chute.

Description

STRAPPING MACHINE WITH STRAP PRE-FEEDPriority

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 663,938, filed June 25, 2024, the entire contents of which is incorporated herein by reference.Field

[0002] The present disclosure relates to strapping machines for forming tensioned loops of strap around loads.Background

[0003] A strapping machine forms a loop of plastic strap (such as polyester or polypropylene strap), metal strap (such as steel strap), or paper strap around a load. Certain strapping machines include a support surface that supports the load, a strap chute that encircles the support surface, a strap reservoir (also called a strap accumulator or a slack box) storing strap in a slack state, a strapping head that forms the strap loop using strap drawn from the strap reservoir, a controller that controls the strapping head to strap the load, and a frame that supports these components. The strap reservoir is periodically replenished via strap drawn from a strap coil. A typical strapping head includes a strap-feeding assembly, a strap-tensioning assembly, and a strap-sealing assembly. The strap-feeding assembly is configured to feed strap from the strap reservoir into and around the strap chute and to retract the strap so it exits the strap chute and moves radially inwardly into engagement with the load with the excess being fed back into the strap reservoir. The strap-tensioning assembly is configured to tension the strap around the load. The strap-sealing assembly is configured to hold the leading end of the strap, to attach two portions of the strap together to form the tensioned strap loop, and to cut the tensioned strap loop from the remaining strap. Certain strapping machines have multiple strapping heads and respective strap chutes that define respective strap paths. These strapping machines areconfigured to simultaneously form multiple tensioned strap loops around a load using strap from separate respective strap supplies.

[0004] To strap the load, the strapping machine carries out a strapping process including a strap-feeding cycle, a strap-retraction cycle, a strap-tensioning cycle, and a strapsealing cycle. The strapping machine first carries out the strap-feeding cycle during which the strap-feeding assembly feeds strap (with the leading strap end first) through the strap-sealing assembly and into and around the strap chute until the leading strap end returns to the strapsealing assembly. The strapping machine then carries out the strap-retraction cycle during which the strap-sealing assembly holds the leading strap end while the strap-feeding assembly retracts the strap to pull the strap out of the strap chute and onto and around the load. The strapping machine then carries out the strap-tensioning cycle during which the strap-tensioning assembly tensions the strap to a designated strap tension. The strapping machine then carries out the strapsealing cycle during which the strap-sealing assembly attaches the leading strap end to another portion of the strap to form a strap joint, thereby forming a tensioned strap loop around the load, and cuts the tensioned strap loop from the remaining strap.

[0005] Press-type strapping machines apply a compressive force to the load to partially compress the load — such as to partially compress a stack of corrugated sheets — and / or to stabilize the load — such as to stabilize a load of stacked lumber — before strapping the load using one or more strapping heads. A typical press-type strapping machine includes a platen supported by the frame and vertically movable relative to the support surface and the load. The platen supports the strap-sealing assembly, and a strap dispenser adjacent the strapping machine supports the strap supply (e.g., a coil of strap) and the strap-feeding and strap-tensioning assemblies. An input chute connects the strap-feeding assembly to the strap-sealing assembly and provides a path for the strap to follow when fed from the strap-feeding assembly to the strapsealing assembly.

[0006] To carry out a strapping process, the press-type strapping machine first carries out a load-compression process. Specifically, the platen first moves downward toward the support surface and into engagement with the load. As the platen continues moving downward, it applies a compressive force to the load. As this occurs, the controller monitors the compressive force the platen applies to the load and stops the platen once the applied compressive force reaches a target compressive force, thereby completing the load-compression process. At thispoint, the load is stabilized and / or partially compressed (depending on the application), and the controller then controls the strapping head(s) to strap the load as explained above. The platen then moves upward away from the support surface and the load to disengage the load and enable the load to be moved out of the strapping machine.

[0007] Figures 1A-1F show a simplified illustration of a press-type strapping machine 1 carrying out this strapping process. A load L is moved onto a support surface of a load supporter 20 beneath a platen 30, as shown in Figure 1 A. The platen 30 descends into engagement with the load L and partially compresses the load L, as shown in Figure IB. The strapping machine 1 carries out the strap-feeding cycle by controlling a strap-feeding assembly to feed strap S from an inlet chute 70, leading strap end first, through a strap-sealing assembly 50 and into and around a strap chute 40 and then controlling the strap-sealing assembly 50 to hold the leading strap end once it traverses the strap chute 40, as shown in Figure 1C. The strapping machine 1 carries out the strap-retraction cycle by controlling the strap-feeding assembly to retract the strap S such that it exits the strap chute 40 and moves radially inwardly into engagement with the load L, as shown in Figure ID. The strapping machine 1 carries out the strap-tensioning cycle by controlling the strap-tensioning assembly to tension the strap S to a designated tension. The strapping machine 1 carries out the strap-sealing cycle by controlling the strap-sealing assembly 50 to attach two portions of the strap S to one another to form a tensioned strap loop TSL around the load L and to cut the tensioned strap loop TSL from the remaining strap S, as shown in Figure IE. The platen 30 ascends and disengages the load L, as shown in Figure IF, completing the strapping process.

[0008] In integrated packaging lines, loads are conveyed from one machine to another to prepare them for shipment before being conveyed to the end of the line where they are loaded into a truck or container. To maximize throughput, packaging line operators strive to minimize the time each load spends idle, i.e., not moving down the packaging line.Summary

[0009] Various embodiments of the present disclosure provide a strapping system including a frame, a load supporter defining a strapping area, a platen movable toward and away from the load supporter, a platen actuator operably connected to the platen and configured tomove the platen toward and away from the load supporter, a strap chute encircling the strapping area, a strapping head, and a controller. The controller is configured to control the platen actuator to begin moving the platen toward a load positioned in the strapping area and, responsive to a strap-feed condition being met based on an applied compressive force the platen applies to the load, control the strapping head to feed strap from a strap supply into and around the strap chute.

[0010] Various embodiments of the present disclosure provide a method of operating a strapping system, including moving a platen toward a load in a strapping area of a load supporter; determining that a strap-feed condition is met based on an applied compressive force the platen applies to the load; and responsive to the strap-feed condition being met, feeding strap from a strap supply into and around a strap chute encircling the strapping area.Brief Description of the Figures

[0011] Figures 1A-1F are simplified elevational views of an example known strapping machine compressing and strapping a load.

[0012] Figure 2 is a perspective view of one example embodiment of a strapping system of the present disclosure.

[0013] Figure 3 is a simplified elevational view of the strapping system of Figure 2.

[0014] Figure 4 is a block diagram showing certain components of the strapping system of Figure 2.

[0015] Figure 5 is a flowchart of an example strapping process of the present disclosure.

[0016] Figures 6A-6F are simplified elevational views of the strapping system of Figure 2 carrying out the strapping process of Figure 5.Detailed Description

[0017] 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 without departing from the spirit or scope of the claims. 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.

[0018] Figures 2-4 show one example embodiment of a press-type strapping system 10 of the present disclosure and components thereof. The strapping system 10 includes a frame 100, a load supporter 200, a platen 300, a platen actuator 350, multiple strap chutes 400 (only one of which is shown for clarity), multiple strapping heads 500 (only one of which is labeled for clarity), multiple strap supplies 600 (only one of which is labeled for clarity), multiple input chutes 700 (only one of which is labeled for clarity), one or more force sensors S, and a controller 800.

[0019] The frame 100 is configured to support some of the components of the strapping system 10. In this example embodiment, the frame 100 includes a base 110, first and second spaced-apart upstanding legs 120 and 130, and a connector 140 that spans and connects the upper ends of the first and second legs 120 and 130. Although not labeled, the first and second legs 120 and 130 each include a vertically extending toothed rack to enable the platen 300 to move relative to the first and second legs 120 and 130 in a rack-and-pinion fashion, as described below. This is merely one example of a configuration of components that form the frame 100, and any other suitable configuration of any other suitable components may form the frame 100 in other embodiments.

[0020] The load supporter 200 is positioned atop the base 110, between the first and second legs 120 and 130, and below the connector 140 of the frame 100. The load supporter 200 is configured to support loads as they are compressed and strapped by and as they move through the strapping system 10. The load supporter 200 includes a support surface 210 on which the loads are positioned during compression and strapping and over which loads move as they move through the strapping system 10. In this example embodiment, the support surface 210 includesmultiple rollers that facilitate movement of the load through the strapping system 10. The rollers may be driven or undriven. In other embodiments, the support surface includes a driven conveyor instead of rollers.

[0021] The platen 300 is supported by the first and second legs 120 and 130 above the load supporter 200 and is vertically movable relative to the load supporter 200 so the platen 300 can adjust to loads of different heights and apply a compressive force to the loads. In this example embodiment, the platen 300 includes two rotatable pinions (not shown) fixed to opposite ends of a pinion shaft 305 such that the pinions and the pinion shaft 305 rotate together. The pinion shaft 305 extends between the first and second legs 120 and 130 such that one pinion meshes with the toothed rack in the first leg 120 and the other pinion meshes with the toothed rack in the second leg 130. In this configuration, rotation of the pinions (which rotate together via their fixed connection to the pinion shaft 305) under control of the platen actuator 350 (described below) causes the pinions to climb or descend their respective toothed racks such that the platen 300 moves away from or toward the support surface 210 of the load supporter 200 (i.e., upward or downward, as described in more detail below). The platen 300 also includes one or more compression surfaces 310 on its underside for engaging and applying the compressive force to the load.

[0022] The platen actuator 350 includes any suitable actuator — such as an electric, pneumatic, or hydraulic motor — operably connected to the platen 300 and configured to move the platen 300 relative to the first and second legs 120 and 130 toward and away from the support surface 210 of the load supporter 200 (i.e., downward and upward). In this example embodiment, the platen actuator 350 is operably connected to the pinions and the pinion shaft 305 of the platen 300 via gearing such that rotation of an output shaft of the platen actuator 350 results in rotation of the pinion shaft 305 and the pinions and vertical movement of the platen 300. In one example embodiment, an output gear of the gearing is meshed with one of the pinions such that rotation of the output gear caused by rotation of the output shaft of the platen actuator 350 directly causes that pinon to rotate, which in turn causes the pinion shaft 305 and the other pinion to rotate. Rotating the output shaft of the platen actuator 350 in one direction results in movement of the platen 300 away from the support surface 210, and rotation of the output shaft in the opposite direction results in movement of the platen 300 toward the support surface 210. This is merely one example embodiment of the platen actuator, and any suitableactuator may be employed. Additionally, any other suitable manner of controlling vertical movement of the platen 300 may be employed (e.g., hydraulic or pneumatic cylinders, belt-and- pulley assemblies, and the like), as the rack-and-pinion configuration is merely one example embodiment.

[0023] Each strap chute 400 encircles the support surface 210 and defines a strap path that the strap traverses when fed into and through the strap chute 400 and from which the strap is removed when retracted onto the load. As shown in Figure 3, the strap chute 400 includes spaced-apart first and second upstanding legs 410 and 420, an upper connecting portion 430 that spans the first and second legs 410 and 420 and is positioned in the platen 300, and a lower connecting portion 440 that spans the first and second legs 410 and 420 and is positioned in the load supporter 200. The strap chute 400 includes a first comer Cl at the junction of the first leg 410 and the upper connecting portion 430, a second comer C2 at the junction of the first leg 410 and the lower connecting portion 440, a third corner C3 at the junction between the second leg 420 and the lower connecting portion 440, and a fourth corner C4 at the junction between the second leg 420 and the upper connecting portion 430.

[0024] A strapping area is defined between the load supporter 200 and the platen 300 and is encircled by the strap chute 400. In this example embodiment, the radially inward walls of the strap chute 400 are formed from multiple gates that are spring biased to a closed position that enables the strap to traverse the strap path when fed through the strap chute 400. When the strapping head 500 later exerts a sufficient pulling force on the strap to retract the strap, the pulling force overcomes the biasing force of the springs and causes the gates to pivot to an open position, thereby releasing the strap from the strap chute so the strap engages the load as the strapping head 500 continues to retract the strap. In other embodiments, the radially inward walls of the strap chute are configured to be actively opened, such as under control of a suitable actuator.

[0025] Each strapping head 500 is configured to form a tensioned strap loop around the load by feeding the strap through one of the strap chutes 400, holding the leading end of the strap while retracting the strap to remove it from the strap chute 400 so it engages the load, tensioning the strap around the load to a designated tension, connecting the leading strap end to another portion of the strap, and cutting the strap from the strap supply. In this example embodiment, the strapping head 500 is a modular strapping head including independentlyremovable and replaceable feed, tensioning, and sealing assemblies 510, 520, and 530. The strapfeeding assembly 510, which is configured to feed and retract the strap, and the strap-tensioning assembly 520, which is configured to tension the strap, are mounted to a frame of the strap supply 600. The platen 300 supports the strap-sealing module 530, which is configured to hold the leading strap end, cut the strap from the strap supply, and connect two portions of the strap to one another. That is, in this example embodiment, the strap-feeding and strap-tensioning assemblies 510 and 520 are located remote from the strap-sealing assembly 530 (though in other embodiments the strap-feeding and / or strap-tensioning assemblies 510 and 520 may be supported by the frame 100, the platen 300, or any other suitable component of the strapping system 10). In this example embodiment, each strapping head is associated with and configured to feed strap into a different one of the strap chutes.

[0026] This is merely one example strapping head, and the strapping system 10 may include any suitable modular strapping head or non-modular strapping head (i.e., a strapping head that is not comprised of independently removable and replaceable feed and sealing modules). The manner of attaching the two portions of the strap to one another depends on the type of strapping machine and the type of strap. Certain strapping systems configured for plastic strap or paper strap include strapping heads with friction welders, heated blades, or ultrasonic welders configured to attach the two portions of the strap to one another. Some strapping systems configured for plastic strap or metal strap include strapping heads with jaws that mechanically deform (referred to as “crimping” in the industry) or cut notches into (referred to as “notching” in the industry) a seal element positioned around the two portions of the strap to attach them to one another. Other strapping systems configured for metal strap include strapping heads with punches and dies configured to form a set of mechanically interlocking cuts in the two portions of the strap to attach them to one another (referred to in the strapping industry as a “sealless” attachment). Still other strapping systems configured for metal strap include strapping heads with spot, inert-gas, or other welders configured to weld the two portions of the strap to one another.

[0027] Each strap supply 600 includes a suitable frame (not labeled) that supports the strap-feeding assembly 510 and the strap-tensioning assembly 520 of the associated strapping head 500 along with a coil of strap.

[0028] Each inlet chute 700 connects the strap-feeding assembly 510 of one of the strapping heads 500 to the strap chute 400 associated with that strapping head 500. In thisexample embodiment, each inlet chute 700 is a flexible tubular member that has an arch shape and defines a strap path between the strap-feeding assembly 510 and the strap-sealing assembly 530 of the associated strapping head 500.

[0029] The one or more force sensors S, which are shown in Figure 4, are configured to sense force, and in particular the compressive force the platen 300 applies to the load. In this example embodiment, the force sensors S are load cells mounted between the frame 100 and the load supporter 200 such that the load supporter 200 is floatingly mounted to the frame 100 via the force sensors S. In this configuration, the force sensors S carry the entire weight of the load supporter 200 and any load on the load supporter 200 and are also subjected to the compressive force the platen 300 applies to the load. In other embodiments, the force sensors S are strain gauges, compression force gauges, or torque gauges. In other embodiments, the force sensors S are mounted to another component of the strapping system 10, such as to the underside of the platen 300. The one or more force sensors S may include any suitable quantity of sensors. In this example embodiment, the one or more force sensors S include four sensors positioned near the four corners of the load supporter 200.

[0030] The controller 800 includes a processing device or devices communicatively connected to a memory device or devices. For instance, the controller may be a programmable logic controller. 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, readonly 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 strapping system 10.

[0031] The controller 800 is communicatively and operably connected to the platen actuator 350 and the strapping heads 500 to receive signals from and to control those components and is communicatively connected to the force sensors S to receive signals fromthose sensors. As described below, the controller 800 is configured to control the platen actuator 350 and the strapping heads 500.

[0032] The controller 800 is configured to determine the applied compressive force the platen 300 applies to a load on the load supporter 200 based on feedback (signals) received from the force sensors S in any suitable manner. In this example embodiment, after a load is introduced atop the load supporter 200 and below the platen 300 into the strapping area of the strapping system 10, the controller 800 determines the combined compressive force exerted on the force sensors S based on feedback from the force sensors S. At this point, this combined compressive force represents the combined force the load and the load supporter 200 exert on the force sensors S via their combined mass — in other words, the combined weight of the load and the load supporter 200. The force sensors S each detect a portion of that combined compressive force (which may or may not be the same for all four sensors) and send respective feedback (e g., force readings) to the controller 800. The controller 800 sums these readings to determine the combined compressive force. For example, a load is introduced into the strapping area of the strapping system 10 atop the load supporter 200. The first force sensor detects a 498 Newton force and sends appropriate feedback to the controller 800. The second force sensor detects a 502 Newton force and sends appropriate feedback to the controller 800. The third force sensor detects a 505 Newton force and sends appropriate feedback to the controller 800. The fourth force sensor detects a 495 Newton force and sends appropriate feedback to the controller 800. The controller 800 uses the combined feedback (such as by summing the force readings) to determine the combined 2,000 Newton compressive force exerted on the force sensors S by the load and the load supporter 200.

[0033] After the platen 300 contacts the load, the combined compressive force exerted on the force sensors S increases due to the addition of the applied compressive force of the platen (which adds to the force the load and the load supporter 200 already exert on the force sensors S). During compression, the force sensors S periodically detect a portion of that combined compressive force (which again may or may not be the same for all four sensors) and send respective feedback (e.g., force readings) to the controller 800. The controller 800 sums these readings to determine the combined compressive force. The controller determines the applied compressive force that the platen 300 applies to the load by determining the difference between the combined compressive force and the compressive force the load and the loadsupporter 200 exert on the force sensors S (i.e., the combined weight of those components). Continuing with the above example, after the platen 300 contacts the load, the first force sensor detects a 748 Newton force and sends an appropriate force reading to the controller 800. The second force sensor detects a 752 Newton force and sends an appropriate force reading to the controller 800. The third force sensor detects a 755 Newton force and sends an appropriate force reading to the controller 800. The fourth force sensor detects a 745 Newton force and sends an appropriate force reading to the controller 800. The controller 800 sums these readings to determine the combined 3,000 Newton compressive exerted on the force sensors S by the load, the load supporter 200, and the platen 300. The controller determines an applied compressive force of 1,000 Newtons by determining the difference between the combined 3,000 Newton compressive force and the 2,000 Newton compressive force applied by the load and the load supporter 200.

[0034] In other embodiments, the controller is configured to zero (or tare) the force sensors after the load is positioned in the strapping area. In these embodiments, after zeroing the force sensors no longer detect the weight of the load supporter or the load, so the applied compressive force is equal to the force reading received from the force sensors. For instance, using the above example, a load is introduced into the strapping area of the strapping machine atop the load supporter. The first force sensor detects a 498 Newton force and sends appropriate feedback to the controller. The second force sensor detects a 502 Newton force and sends appropriate feedback to the controller. The third force sensor detects a 505 Newton force and sends appropriate feedback to the controller. The fourth force sensor detects a 495 Newton force and sends appropriate feedback to the controller. The controller zeroes (or tares) the force sensors. After the platen contacts the load, the first force sensor detects a 250 Newton force and sends an appropriate force reading to the controller. The second force sensor detects a 250 Newton force and sends an appropriate force reading to the controller. The third force sensor detects a 250 Newton force and sends an appropriate force reading to the controller. The fourth force sensor detects a 250 Newton force and sends an appropriate force reading to the controller. The controller sums these readings to determine an applied compressive force of 1,000 Newtons.

[0035] The controller 800 is configured to control the platen actuator 350 and the strapping heads 500 to carry out a strapping process that generally includes a load-compression process, a strap-feeding cycle, a strap-retraction cycle, a strap-tensioning cycle, and a strap-sealing cycle. The controller 800 is configured to start the load-compression process, monitor the applied compressive force the platen applies to the load, start the strap-feeding cycle responsive to a strap-feed condition being met based on the applied compressive force, and start the strapretraction cycle once the load-compression process and the strap-feeding cycle are complete. The strap-retraction cycle is followed by the strap-tensioning and strap-sealing cycles. The strap-feed condition is met before the load-compression process is completed. In other words, the controller 800 is configured to control the strapping heads 500 to start feeding strap into and around the strap chutes 400 while the platen 300 is still descending and compressing the load, and then to control the strapping heads 500 to retract, tension, and seal the strap after the load has been compressed. By starting the strap-feeding cycle before completing the load-compression process, the strapping system of the present disclosure decreases cycle time and increases throughput compared to certain prior art strapping systems that do not initiate the strap-feeding cycle until the load-compression process is complete.

[0036] In this example embodiment, the load-compression process is complete when the applied compressive force reaches a target compressive force, which may be any suitable value. The strap-feed condition is met when the applied compressive force reaches a feed compressive force that is less than the target compressive force (but which may itself be any suitable value).

[0037] Operation of the strapping system 10 to carry out a strapping process 1000 is now described in conjunction with the flowchart shown in Figure 5 and the example embodiment of the strapping system shown in Figures 6A-6F.

[0038] Before the strapping process 1000 begins in this example embodiment, a load LI is introduced into the strapping system 10. In this example embodiment, the load LI is moved atop the support surface 210 of the load supporter 200 and into the strapping area of the strapping system 10, as shown in Figure 6A. The strapping process 1000 begins with beginning to move a platen toward a load on a support surface while monitoring a compressive force applied to the load by the platen, as block 1002 indicates. In this example embodiment, the controller 800 controls the platen actuator 350 to begin moving the platen 300 toward the support surface 210 and into contact with the upper surface of the load LI. As this occurs, the controller 800 determines the applied compressive force the platen 300 applies to the load LI based on feedback from the force sensors S, as explained above. The strapping process 1000 continues bydetermining whether a strap-feed condition is met based on the compressive force applied to the load by the platen, as diamond 1004 indicates. As explained above, in this example embodiment, the strap-feed condition is met when the applied compressive force by the platen 300 reaches a feed compressive force, and the controller 800 is configured to periodically compare the applied compressive force to the feed compressive force. If the strap-feed condition is not met, the platen continues moving toward the load.

[0039] If, on the other hand, the strap-feed condition is met, the strapping process 1000 continues by feeding strap from a strap supply into and around a strap chute that encircles the load, as block 1006 indicates. This strap feeding step starts while the platen continues moving toward the load. In this example embodiment, when the controller 800 determines that the applied compressive force reaches the feed compressive force, the controller 800 controls the strap-feeding assembly 510 to begin feeding strap S leading strap end LE first through the input chute 700, through the strap-sealing assembly 530, and into and around the strap chute 400 until the leading strap end LE returns to the strap sealing assembly 530. When this occurs, the controller 500 controls the strap-sealing assembly 530 to hold the leading strap end LE and controls the strap-feeding assembly 510 to stop feeding the strap S, thereby completing the strapfeeding cycle. Figure 6B shows the strapping system 10 after the strap-feed condition is met and the strap-feeding assembly 510 has started to feed the strap into the strap chute 400, and Figure 6C shows the strapping system 10 after the strap-feeding cycle is complete.

[0040] The strapping process 1000 continues by continuing to move the platen toward the load while monitoring the compressive force applied to the load by the platen, as block 1008 indicates. In this example embodiment, the controller 800 continues to control the platen actuator 350 to move the platen 300 toward the support surface 210. The strapping process 1000 continues by determine whether the compressive force applied to the load by the platen has reached a target compressive force, as diamond 1010 indicates. In this example embodiment, the controller 800 is configured to periodically compare the applied compressive force to the target compressive force. If the applied compressive force has not reached the target compressive force, the platen continues moving toward the load.

[0041] If, on the other hand, the applied compressive force has reached the target compressive force, the strapping process 1000 continues by stopping movement of the platen toward the load, as block 1012 indicates. In this example embodiment, the controller 800controls the platen actuator 350 to stop the platen 300. The strapping process 1000 concludes by retracting the strap from the strap chute and onto the load, as block 1014 indicates; tensioning the strap, as block 1016 indicates; and attaching two portions of the strap to one another to form a tensioned strap loop around the load and separating the tensioned strap loop from the strap supply, as block 1018 indicates. In this example embodiment, the controller 800 controls the strap-feeding assembly 510 to retract the strap S so that it exits the strap chute 400 and moves radially inwardly and engages the load LI, as shown in Figure 6D; controls the strap-tensioning assembly 520 to tension the strap around the load; and controls the strap-sealing assembly 530 to attach the two portions of the strap to one another, as shown in Figure 6E. Figure 6F shows the strapping system 10 after the platen 300 has been raised to enable the load to be moved..

[0042] In certain embodiments, the strap-feeding cycle starts and finishes before the platen stops descending, i.e., before the load-compression process is completed. In other embodiments, the strap-feeding cycle starts before and finishes after the platen stops descending, i.e., starts before and finishes after the load-compression process is completed. In other embodiments, the strap-feeding cycle starts before the platen stops descending, i.e., before the load-compression process is completed, and finishes at substantially the same time as the platen stops descending, i.e., at substantially the same time as the load-compression process is completed.

[0043] In various embodiments, the feed compressive force and the target compressive force are received from operators of the strapping system, such as via an input device of the strapping system. In certain embodiments, the controller is configured to determine and set the target compressive force based on one or more factors — such as the compressibility of the load, the anticipated speed of the platen, and / or the anticipated cycle time for the strapfeeding cycle — such that the strap-feeding cycle and the load-compression process finish at substantially the same time.

[0044] In certain embodiments, for a constant target compressive force, the feed compressive force for a first load is greater than the feed compressive force for a second load when the first load is more compressible than the second load.

[0045] In other embodiments, the strapping system does not include force sensors. In these embodiments, the controller is configured to estimate the applied compressive force bymonitoring the electrical current drawn by the platen actuator as it compresses the load and converting the electrical current value into an estimated force value.

Claims

Claims1. A strapping system comprising: a frame; a load supporter defining a strapping area; a platen movable toward and away from the load supporter; a platen actuator operably connected to the platen and configured to move the platen toward and away from the load supporter; a strap chute encircling the strapping area; a strapping head; and a controller configured to control the platen actuator to begin moving the platen toward a load positioned in the strapping area and, responsive to a strap-feed condition being met based on an applied compressive force the platen applies to the load, control the strapping head to begin feeding strap from a strap supply into and around the strap chute while continuing to control the platen actuator to move the platen toward the load.

2. The strapping system of claim 1, wherein the controller is further configured to, after the strap-feed condition is met and responsive to the applied compressive force reaching a target compressive force, control the strapping head to: retract the strap such that the strap exits the strap chute and engages the load; tension the strap around the load; and attach two portions of the strap to one another to form a tensioned strap loop around the load.

3. The strapping system of claim 2, wherein the controller is further configured to determine the applied compressive force.

4. The strapping system of claim 3, further comprising one or more force sensors, wherein the controller is further configured to determine the applied compressive force based on feedback from the one or more force sensors.

5. The strapping system of claim 2, wherein the strapping head comprises a strapfeeding assembly configured to feed and retract the strap, a strap-tensioning assembly configured to tension the strap, and a strap-sealing assembly configured to attach the two portions of the strap to one another, wherein the platen supports the strap-sealing assembly, wherein the strapfeeding assembly and the strap-tensioning assembly are located separately from the strap-sealing assembly.

6. The strapping system of claim 2, wherein the controller is further configured to determine that the strap-feed condition is met when the applied compressive force reaches a feed compressive force that is less than the target compressive force.

7. The strapping system of claim 6, wherein the feed compressive force is a first feed compressive force for a first load and a second feed compressive force for a second load, wherein the first feed compressive force is greater than the second feed compressive force, wherein the first load is more compressible than the second load.

8. The strapping system of claim 2, wherein the controller is further configured to control the strapping head to feed strap from the strap supply into and around the strap chute until a leading end of the strap reaches an end point.

9. The strapping system of claim 8, wherein the controller is further configured to control the platen actuator and the strapping head such that the leading end of the strap reaches the end point at substantially the same time as the applied compressive force reaches the target compressive force.

10. The strapping system of claim 8, wherein the controller is further configured to control the platen actuator and the strapping head such that the leading end of the strap reaches the end point before the applied compressive force reaches the target compressive force.

11. The strapping system of claim 8, wherein the controller is further configured to determine that the strap-feed condition is met when the applied compressive force reaches a feed compressive force that is less than the target compressive force, wherein the controller is furtherconfigured to set the feed compressive force such that the leading end of the strap reaches the end point at substantially the same time as the applied compressive force reaches the target compressive force.

12. A method of operating a strapping system, the method comprising: moving a platen toward a load in a strapping area of a load supporter; determining that a strap-feed condition is met based on an applied compressive force the platen applies to the load; and responsive to the strap-feed condition being met, begin feeding strap from a strap supply into and around a strap chute encircling the strapping area while continuing to move the platen toward the load.

13. The method of claim 12, further comprising, after determining that the strap-feed condition is met: determining that the applied compressive force has reached a target compressive force; and responsive to determining that the applied compressive force has reached the target compressive force: retracting the strap such that the strap exits the strap chute and engages the load; tensioning the strap around the load; and attaching two portions of the strap to one another to form a tensioned strap loop around the load.

14. The method of claim 13, further comprising determining the applied compressive force.

15. The method of claim 14, further comprising determining the applied compressive force based on feedback from one or more force sensors.

16. The method of claim 13, further comprising determining that the strap-feed condition is met when the applied compressive force reaches a feed compressive force that is less than the target compressive force.

17. The method of claim 16, wherein the feed compressive force is a first feed compressive force for a first load and a second feed compressive force for a second load, wherein the first feed compressive force is greater than the second feed compressive force, wherein the first load is more compressible than the second load.

18. The method of claim 13, further comprising feeding strap from the strap supply into and around the strap chute until a leading end of the strap reaches an end point.

19. The method of claim 18, further comprising controlling movement of the platen and feeding of the strap such that the leading end of the strap reaches the end point at substantially the same time as the applied compressive force reaches the target compressive force.

20. The method of claim 18, further comprising: determining that the strap-feed condition is met when the applied compressive force reaches a feed compressive force that is less than the target compressive force; and setting the feed compressive force such that the leading end of the strap reaches the end point at substantially the same time as the applied compressive force reaches the target compressive force.

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