Strapping machine configured to control the force exerted on strap between a drive roller and a counter roller

Abstract

Strapping device (10) configured to control the force exerted on strap between a drive roller (512) and a counter roller (514). In one embodiment, the strapping machine includes a drive roller, a drive-roller actuator (512a) operably connected to the drive roller and configured to rotate the drive roller, a counter roller, a force sensor (516) configured to detect a force exerted on strap between the drive roller and the counter roller, an actuator (514a) operably connected to one of the drive roller and the counter roller, and a controller (800). The controller is configured to monitor the detected force and, responsive to a force-change condition being met based on the detected force, control the actuator to cause the force exerted on the strap between the drive roller and the counter roller to change.

Description

STRAPPING MACHINE CONFIGURED TO CONTROL THE FORCE EXERTED ONSTRAP BETWEEN A DRIVE ROLLER AND A COUNTER ROLLERPriority

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 561,455, filed March 5, 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 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 definerespective strap paths. These strapping machines are configured 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 strapping cycle including a strap-feeding process, a strap-retraction process, a strap-tensioning process, and a strap-sealing process. The strapping machine first carries out the strap-feeding process during which the strapfeeding 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 strap-sealing assembly. The strapping machine then carries out the strap-retraction process 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 process during which the strap-tensioning assembly tensions the strap to a designated strap tension. The strapping machine then carries out the strap-sealing process 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] A typical strap-feeding assembly includes a motor-driven drive roller and a counter roller biased by a spring into engagement with the drive roller. When strap is introduced between the drive roller and the counter roller, the spring compresses or extends — depending on the type of spring — so the counter roller can move away from the drive roller and make room for the strap. Once the strap is between the drive roller and the counter roller, the counter roller exerts a force on the strap via the spring. To prevent slippage between the drive roller and the strap when the motor rotates the drive roller — i.e., to prevent the drive roller from rotating but not moving the strap — that force must exceed a threshold force.

[0006] Due to variations in the strap itself, such as its thickness and composition, and in environmental factors, such as the ambient temperature and the temperature inside the strap-feeding assembly, in certain instances the spring cannot cause the counter roller to exert the target force on the strap. To avoid undesired slippage, the operator must recognize this and troubleshoot it, such as by adding another spring or swapping the spring for a stronger one.Summary

[0007] Various embodiments of the present disclosure provide a strapping machine configured to control the force exerted on strap between a drive roller and a counter roller. In one embodiment, the strapping machine includes a drive roller, a drive-roller actuator operably connected to the drive roller and configured to rotate the drive roller, a counter roller, a force sensor configured to detect a force exerted on strap between the drive roller and the counter roller, an actuator operably connected to one of the drive roller and the counter roller, and a controller. The controller is configured to monitor the detected force and, responsive to a forcechange condition being met based on the detected force, control the actuator to cause the force exerted on the strap between the drive roller and the counter roller to change.Brief Description of the Figures

[0008] Figure l is a perspective view of one example embodiment of a strapping system of the present disclosure.

[0009] Figure 2 is a block diagram showing certain components of the strapping system of Figure 1.

[0010] Figure 3 is a simplified elevational view of the strap-feeding assembly of the strapping system of Figure 1.

[0011] Figure 4 is a flowchart showing an example force-monitoring method of the present disclosure.

[0012] Figures 5A and 5B are similar to Figure 3 but show strap of different thicknesses introduced into the strap-feeding assembly.

[0013] Figures 6A-6F are simplified elevational views of the strapping system of Figure 1 applying a tensioned strap loop to a load.Detailed Description

[0014] 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 thespecification 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.

[0015] Figures 1-3 show one example embodiment of a strapping machine 10 of the present disclosure and components thereof. The strapping machine 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), and a controller 800.

[0016] The frame 100 is configured to support some of the components of the strapping machine 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.

[0017] 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 machine 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 movethrough the strapping machine 10. In this example embodiment, the support surface 210 includes multiple rollers that facilitate movement of the load through the strapping machine 10. The rollers may be driven or undriven. In other embodiments, the support surface includes a driven conveyor instead of rollers.

[0018] 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 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.

[0019] The platen actuator 350 is 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 merelyone example embodiment of the platen actuator, and any suitable actuator 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.

[0020] Each strap chute 400 encircles the support surface 210 and defines a strap path that the strap follows when fed through the strap chute 400 and from which the strap is removed when retracted onto the load. As shown in Figure 5A, 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. 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.

[0021] 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 independently removable 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 toone 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 machine 10). In this example embodiment, each strapping head is associated with and configured to feed strap into a different one of the strap chutes.

[0022] Figure 3 shows certain components of the strap-feeding assembly 510. Specifically, the strap-feeding assembly 510 includes a drive roller 512, a drive-roller actuator 512a, a counter roller 514, a counter-roller actuator 514a, and a force sensor 516.

[0023] The drive roller 512 is disc-shaped and is mounted to a suitable component of the strap-feeding assembly 510 such that the drive roller is rotatable. The drive-roller actuator 512a, which may be an electric motor or any other suitable actuator, is operably connected to the drive roller 512 and configured to rotate the drive roller 512. The drive-roller actuator 512a may be operably connected to the drive roller 512 in any suitable manner, such as via a keyed or splined connection or via a suitable drive train.

[0024] The counter roller 514 is disc-shaped and is mounted to a suitable component of the strap-feeding assembly 510 such that the counter roller 514 is freely rotatable. The counter-roller actuator 514a, which may be a linear actuator, a pneumatic or hydraulic cylinder, or any other suitable actuator, is operably connected to the counter roller 514 and configured to move the counter roller 514 toward and away from the drive roller 512. In other words, the counter-roller actuator 514a is configured to change the position of the counter roller 514 relative to the drive roller 512.

[0025] The force sensor 516, which is a load cell in this example embodiment but may be any other suitable type of force sensor in other embodiments, is positioned and otherwise configured to sense the force the counter roller 514 exerts on strap (not shown in Figure 3) positioned between the drive roller 512 and the counter roller 514. In this example embodiment, the force sensor 516 is positioned between the counter-roller actuator 514a and the counter roller 514, though the force sensor 516 may be positioned in any other suitable location in other embodiments. As described below in connection with Figure 4, feedback from the force sensor 516 is used to control the counter-roller actuator 514a to control the position of the counter roller514 relative to the drive roller 512 and, therefore, to control the force the counter roller 514 exerts on the strap between the drive roller 512 and the counter roller 514.

[0026] This is merely one example strapping head, and the strapping machine 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, the strap-tensioning assembly 520, and 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 this example 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 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 machine 10.

[0030] 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. As described below, the controller 800 is configured to receive feedback from the force sensor 516 and to control the platen actuator 350 and the strapping heads 500, including the drive-roller actuator 512a and the counter-roller actuator 514a.

[0031] To prevent slippage between the drive roller 512 and the strap when the drive-roller actuator 512a rotates the drive roller 512, the counter-roller 514 must exert a target force — or substantially the target force or a force within a target force range — on the strap. To do so, the controller 800 is configured to carry out a force-monitoring process 1000 shown in Figure 4 during operation of the strapping machine 10.

[0032] The force-monitoring process 1000 begins by monitoring the force exerted on strap between a drive roller and a counter roller, as block 1010 indicates. The force-monitoring process 1000 continues by determining whether a force-change condition has been met, as diamond 1020 indicates. If the force-change condition has not been met, the force-monitoring process 1000 continues by returning to block 1010. If the force-change condition has been met, the force-monitoring process 1000 continues by controlling an actuator to cause the force exerted on the strap to change, as block 1030 indicates. The force-monitoring process 1000 continues by returning to block 1010.

[0033] In this example embodiment, the controller 800 — and in particular, a Proportional — Integral — Derivative (PID) module of the controller 800 — is configured to carry out the force-monitoring process 1000. The controller 800 does so by using feedback from the force sensor 516 to control the position of the counter roller 514 relative to the drive roller 512 (and the strap between the drive roller 512 and the counter roller 514) such that the force the counter roller 514 exerts on the strap between the drive roller 512 and the counter roller 514 is equal or substantially equal to a force setpoint. Specifically, in this example embodiment, the controller 800 periodically receives feedback from the force sensor 516 that represents the forcethe counter roller 514 exerts on the strap between the drive roller 512 and the counter roller 514. The controller 800 compares this measured force to a force setpoint stored in the memory device. If the measured force differs from the force setpoint by at least a designated amount, the forcechange condition is met. In this example embodiment, the designated amount is any amount. In other embodiments, the designated amount is a particular percentage of the force setpoint (e.g. 1% of the force setpoint) or any other suitable amount. In response, the controller 800 is configured to: (1) if the measured force is less than the force setpoint, control the counter-roller actuator 514a to move the counter roller 514 toward the drive roller 512 to increase the force the counter roller 514 exerts on the strap; or (2) if the measured force is greater than the force setpoint, control the counter-roller actuator 514a to move the counter roller 514 away from the drive roller 512 to decrease the force the counter roller 514 exerts on the strap. In this example embodiment, the controller 116 is therefore configured to modulate the position of the counter roller 514 relative to the drive roller 512 to converge the measured force to the force setpoint.The force setpoint may be preset and in certain embodiments can differ depending on the type of strap being used in the strapping machine (e.g., one type of strap has a first force setpoint and another type of strap has a second, different force setpoint).

[0034] Figure 5 A shows the strap-feeding assembly 510 with first strap SI of a first thickness tl between the drive roller 512 and the counter roller 514. Figure 5B shows the same strap-feeding assembly 510 after the first strap SI has been swapped with second strap S2 of a second thickness t2 that is less than the first thickness tl. Because the second strap S2 is thinner than the first strap SI, the controller 800 controls the counter-roller actuator 514a to move the counter roller 514 toward the drive roller 512 until the force measured by the force sensor 516 meets the force setpoint.

[0035] Monitoring and, when necessary, controlling an actuator to maintain the force exerted on strap between a drive roller and a counter roller at a target force ensures that the drive roller will be able to move strap through the strap-feeding assembly without slippage. It also eliminates the need for operators to recognize when slippage is occurring and mechanically modify the strapping machine to remedy the problem.

[0036] Operation of the strapping machine 10 to carry out a strapping process is now described in conjunction with the Figures 6A-6F. The load L is moved to the strapping area of the strapping machine 10, as shown in Figure 6A. The controller 800 then controls the platenactuator 350 to begin moving the platen 300 toward the support surface 210 and, eventually, stops the platen 300 after the platen 300 engages the load L. In certain embodiments, the controller 800 monitors the amount of compressive force the platen 300 applies to the load L, such as via a compression sensor, and stops the platen 300 once the applied compressive force reaches a predefined threshold. In other embodiments, the controller 800 monitors the position of the platen 300, such as via a distance sensor, and stops the platen 300 once the platen 300 is a predetermined distance above the support surface 210. Figure 6B shows the strapping machine 10 after the platen 300 has engaged the load L and stopped descending.

[0037] The controller 800 controls the strapping head 500 to carry out the strapfeeding process. Specifically, the controller 800 controls the strap-feeding assembly 510 to feed strap S through the input chute 700, through the strap-sealing assembly 530, and into and around the strap chute 400 and controls the strap-sealing assembly 530 to hold the leading end of the strap S after it traverses the strap chute 400 and returns to the strap-sealing assembly 530. Figure 6C shows the strapping machine 10 after the strap-feeding process has been completed.

[0038] 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 L. Figure 6D shows the strapping machine 10 after the strap S has exited the strap chute 400 and engaged the load L. The controller 800 controls the strap-tensioning assembly 520 to tension the strap S around the load to a designated tension and controls the strap-sealing assembly 530 to attach two portions of the strap S to one another and to cut the strap S from the strap supply to form a tensioned strap loop TSL around the load L. Figure 6E shows the strapping machine 10 after the strap S has been tensioned, sealed, and cut to form the tensioned strap loop TSL. The controller 800 controls the platen actuator 350 to raise the platen 300 until it disengages the load L so the load L can be moved out of the strapping machine 10. Figure 6F shows the strapping machine 10 after the load L has been moved.

[0039] In other embodiments, the force-change condition is met when the force monitored by the force sensor is outside of the upper and lower bounds of a target force range. The target force range may be preset and in certain embodiments can differ depending on the type of strap being used in the strapping machine (e.g., one type of strap has a first target force range and another type of strap has a second, different target force range). In these embodiments, responsive to the force-change condition being met, the controller controls the counter-rolleractuator to move the counter roller: (1) if the monitored force is below the lower bound of the target force range, toward the drive roller until the monitored force is within the target force range; or (2) if the monitored force is above the upper bound of the target force range, away from the drive roller until the monitored force is within the target force range.

[0040] In certain embodiments, the force-monitoring process and associated mechanical components are implemented in the strap-tensioning assembly as well as or in addition to being implemented in the strap-feeding assembly. In these embodiments, the straptensioning assembly includes a tensioning drive roller and associated actuator, a tensioning counter roller and associated actuator, and a force sensor configured to sense the force the tensioning counter roller exerts on strap between the tensioning drive roller and the tensioning counter roller. In these embodiments, the controller is configured to carry out the forcemonitoring process and modulate the position of the tensioning counter roller to maintain the force at a force setpoint.

[0041] Characteristics of the strap may vary based on temperature. For instance, certain strap may become more compliant when its temperature exceeds a certain threshold. In certain embodiments, the strapping machine includes a temperature sensor configured to sense the temperature within the strap-feeding assembly (and / or the strap-tensioning assembly). The controller is configured to modify the force setpoint (or target force range) based on the temperature. In other words, for a particular type of strap, the force setpoint may be a first force setpoint when the temperature is below a threshold temperature and a second, different force setpoint when the temperature exceeds the threshold temperature.

[0042] In alternative embodiments, the counter-roller actuator includes a cam fixed to a camshaft rotated by a motor or other suitable rotary actuator. In these embodiments, the counter roller is mounted to a cam follower that is spring biased into engagement with the cam. The cam is shaped such that rotation of the camshaft results in translation of the cam follower — and the counter roller mounted to it — toward or away from the drive roller depending on the extent of the rotation and the shape of the cam.

[0043] In certain embodiments, the counter roller is fixed in translation relative to the drive roller, and the drive roller is movable via a suitable actuator toward and away from the counter roller to increase or decrease the force exerted on the strap between the drive roller and the counter roller.

[0044] In various embodiments, the controller is configured to prevent the strapping machine from initiating a strapping cycle until the detected force is equal or substantially equal to the force setpoint (or until it is within the target force range).

[0045] In certain embodiments, a spring is positioned between the counter roller and the counter-roller actuator so the counter roller can vary in position (e.g., by compression and extension of the spring). This, for instance, enables the counter roller to move slightly toward or away from the drive roller to compensate for slight variations in strap thickness without requiring operation of the counter-roller actuator.

Claims

Claims1. A strapping device comprising: a drive roller; a drive-roller actuator operably connected to the drive roller and configured to rotate the drive roller; a counter roller; a force sensor configured to detect a force exerted on strap between the drive roller and the counter roller; an actuator operably connected to one of the drive roller and the counter roller; and a controller configured to monitor the detected force and, responsive to a force-change condition being met based on the detected force, control the actuator to cause the force exerted on the strap between the drive roller and the counter roller to change.

2. The strapping device of claim 1, wherein the controller is configured to, responsive to the force-change condition being met, control the actuator to move the one of the drive roller and the counter roller relative to the other of the drive roller and the counter roller to cause the force exerted on the strap to change.

3. The strapping device of claim 2, wherein the controller is configured to determine that the force-change condition is met when the detected force differs from a force setpoint by at least a designated amount.

4. The strapping device of claim 3, wherein the controller is configured to, responsive to the force-change condition being met: if the detected force is less than the force setpoint, control the actuator to cause the one of the drive roller and the counter roller to move toward the other of the drive roller and the counter roller to increase the force exerted on the strap; and if the detected force is greater than the force setpoint, control the actuator to cause the one of the drive roller and the counter roller to move away from the other of the drive roller and the counter roller to decrease the force exerted on the strap.

5. The strapping device of claim 4, wherein the actuator comprises one of a linear actuator and a rotary actuator.

6. The strapping device of claim 2, wherein the controller is configured to determine that the force-change condition is met when the detected force is outside of a target force range.

7. The strapping device of claim 6, wherein the controller is configured to, responsive to the force-change condition being met, control the actuator to move the one of the drive roller and the counter roller relative to the other of the drive roller and the counter roller until the force exerted on the strap is within the target force range.

8. The strapping device of claim 1, wherein the force sensor is between the actuator and the one of the drive roller and the counter roller.

9. The strapping device of claim 1, wherein the actuator is operably connected to the counter roller and configured to move the counter roller toward and away from the drive roller.

10. A method comprising: detecting a force exerted on strap between a drive roller and a counter roller of a strapping machine; monitoring the detected force; determining that a force-change condition has been met based on the detected force; and responsive to determining that the force-change condition has been met, controlling an actuator to cause the force exerted on the strap to change.

11. The method of claim 10, further comprising, responsive to determining that the force-change condition has been met, controlling the actuator to move one of the drive roller and the counter roller relative to the other of the drive roller and the counter roller to cause the force exerted on the strap to change.

12. The method of claim 11, further comprising determining that the force-change condition is met when the detected force differs from a force setpoint by at least a designated amount.

13. The method of claim 12, further comprising, responsive to determining that the force-change condition has been met: if the detected force is less than the force setpoint, controlling the actuator to cause the one of the drive roller and the counter roller to move toward the other of the drive roller and the counter roller to increase the force exerted on the strap; and if the detected force is greater than the force setpoint, controlling the actuator to cause the one of the drive roller and the counter roller to move away from the other of the drive roller and the counter roller to decrease the force exerted on the strap.

14. The method of claim 11, further comprising determining that the force-change condition is met when the detected force is outside of a target force range.

15. The method of claim 14, further comprising, responsive to determining that the force-change condition has been met, controlling the actuator to move the one of the drive roller and the counter roller relative to the other of the drive roller and the counter roller until the force exerted on the strap is within the target force range.

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