Packaging machine with a carriage-locking device

Abstract

Various embodiments of the present disclosure provide a packaging machine comprising a load supporter, a rack comprising a base and multiple teeth extending from the base, a carriage vertically movable relative to the rack and the load supporter, a carriage actuator operably connected to the carriage to vertically move the carriage, and a carriage-locking device supported by and movable with the carriage. The carriage-locking device includes a lock movable between an engaged position and a disengaged position. When the lock is in the engaged position, the lock is positioned to contact one of the teeth of the rack and prevent the carriage from descending toward the load supporter. When the lock is in the disengaged position, the lock is positioned not to prevent the carriage from descending toward the load supporter.

Description

PACKAGING MACHINE WITH A CARRIAGE-LOCKING DEVICEPriority

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 608,449, filed December 11, 2023, and U.S. Provisional Patent Application No. 63 / 649,595, filed May 20, 2024, the entire contents of both of which are incorporated herein by reference.Field

[0002] The present disclosure relates to packaging machines for applying packaging material to loads.Background

[0003] There are many types of packaging machines for applying packaging material to loads to bundle or unitize the loads in preparation for future transport. Some examples of these packaging machines include strapping machines that apply plastic, paper, or steel strap around loads; wrapping machines that apply plastic stretch film or paper around loads; and stretchhooding machines that apply a hood of plastic stretch film around loads. These packaging machines include a vertically movable carriage that supports components that assist in applying the packaging material and that enables the packaging machine to adapt to loads of different heights.

[0004] For example, certain strapping machines include a carriage that supports at least part of a strapping head configured to form a tensioned strap loop around the load. The carriage moves vertically to accommodate the load — and in certain strapping machines compresses the load — before the strapping head forms the tensioned strap loop. Certain wrapping machines include a carriage that supports a rotatable ring that itself supports a film carriage including a roll of plastic stretch film. The carriage moves vertically while the ring rotates to apply the plastic stretch film to the load in a helical pattern. Certain stretch-hooding machines include a carriage that includes multiple reefing fingers. The reefing fingers gather andstretch the hood of plastic stretch film above the load, and afterward the carriage descends while the reefing fingers dispense the hood of plastic stretch film onto the load.

[0005] Packaging machines are typically deenergized before they are serviced or otherwise scheduled for downtime. Suspension brackets are used to prevent the carriage from descending when the packaging machine is deenergized. To install the suspension brackets, the operator controls the packaging machine to move the carriage to a particular position above the floor. While the motor controlling the carriage suspends it in place, the operator manually unlocks and moves the suspension brackets into place below the carriage. The operator then controls the packaging machine to move the carriage downward into contact with the suspension brackets so the carriage rests on the suspension brackets, at which point the packaging machine can be deenergized.

[0006] Existing suspension brackets can suspend the carriage in place at one particular position, which requires the operator to move the carriage to a specific position each time the operator wants to suspend the carriage. These suspension brackets also require the operator to manually position them, which requires the operator to move away from the control area to do so or requires a second operator to help. Not only is this inconvenient for operators, but it also takes time to complete, reducing efficiency.Summary

[0007] Various embodiments of the present disclosure provide a packaging machine comprising a load supporter, a rack comprising a base and multiple teeth extending from the base, a carriage vertically movable relative to the rack and the load supporter, a carriage actuator operably connected to the carriage to vertically move the carriage, and a carriage-locking device supported by and movable with the carriage. The carriage-locking device includes a lock movable between an engaged position and a disengaged position. When the lock is in the engaged position, the lock is positioned to contact one of the teeth of the rack and prevent the carriage from descending toward the load supporter. When the lock is in the disengaged position, the lock is positioned not to prevent the carriage from descending toward the load supporter.Brief Description of the Figures

[0008] Figure l is a perspective view of one example embodiment of a packaging machine of the present disclosure in the form of a strapping machine.

[0009] Figure 2 is a front elevational view of the strapping machine of Figure 1.

[0010] Figure 3 is a block diagram of certain components of the strapping machine of Figure 1.

[0011] Figures 4A and 4B are assembled and exploded perspective views, respectively, of a carriage-locking device of the strapping machine of Figure 1.

[0012] Figures 5A and 5B are cross-sectional front elevational views of the carriagelocking device of Figure 4A taken substantially along line 5A-5A of Figure 4A that show the lock of the carriage-locking device in engaged and disengaged positions, respectively.

[0013] Figures 6A-6C are front elevational views of the carriage-locking device of Figure 4A and a locking rack of the strapping machine of Figure 1 that show the lock of the carriage-locking device being disengaged.

[0014] Figures 7A-7D are front elevational views of the carriage-locking device of Figure 4A and the locking rack of Figures 6A-6C that show the lock of the carriage-locking device being engaged.

[0015] Figures 8A-8F are simplified front elevational views of the strapping machine of Figure 1 compressing and strapping a load.Detailed Description

[0016] 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 thatrefer 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.

[0017] Various embodiments of the present disclosure provide a packaging machine including a carriage, a locking rack, and a carriage-locking device. The carriage-locking device includes a lock movable between an engaged position in which the lock is positioned to contact the locking rack to prevent the carriage from descending and a disengaged position in which the lock is positioned so it does not prevent the carriage from descending. Figures 1-8F show one example embodiment of the packaging machine of the present disclosure and components thereof in the form of a press-type strapping machine 10, though the packaging machine may be another type of strapping machine, a wrapping machine, a stretch-hooding machine, or any other type of packaging machine in other embodiments. The strapping machine 10 includes a frame 100, a load supporter 200, a carriage 300, a carriage actuator 350, strap chutes 400a-400f, strapping heads 500a-500f, strap supplies 600a-600f, input chutes 700a-700f, a first locking rack 800a, a second locking rack 800b, a first carriage-locking device 900, a second carriagelocking device 1000, and a controller 2000.

[0018] The frame 100 is configured to support certain 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 carriage 300 to move vertically 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.

[0019] 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 theloads are positioned during compression and strapping and over which loads move as they move through 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.

[0020] The carriage 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 carriage 300 can adjust to loads of different heights and apply a compressive force to the loads. In this example embodiment, the carriage 300 includes a carriage frame 310 that rotatably supports (such as via suitable bearings) a pinion shaft 305 having one rotatable pinion at each of its opposite ends. The pinions are fixed in rotation with the pinion shaft 305 so 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 carriage actuator 350 (described below) causes the pinions to climb or descend their respective toothed racks such that the carriage 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 carriage frame 310 includes one or more compression surfaces on its underside for engaging and applying the compressive force to the load.

[0021] The carriage actuator 350 includes any suitable actuator, such as an electric, pneumatic, or hydraulic motor, operably connected to the carriage 300 and configured to move the carriage 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 carriage actuator 350 is mounted to the carriage frame 310 and is operably connected to the pinions and the pinion shaft 305 of the carriage 300 via suitable gearing or other components such that rotation of an output shaft of the carriage actuator 350 results in rotation of the pinion shaft 305 and the pinions and vertical movement of the carriage 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 carriage 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 carriage actuator 350 in one direction results in movement of the carriage 300 away from the support surface 210, and rotation of the output shaft in the opposite direction results in movement of the carriage 300 toward the support surface 210. This is merely one example embodiment of the carriage actuator, and any suitable actuator may be employed. Additionally, any other suitable manner of controlling vertical movement of the carriage 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.

[0022] The strap chutes 400a-400f are spaced apart, and each encircles the support surface 210 and defines a strap path that the strap follows when fed through that strap chute and from which the strap is removed when retracted onto the load. As best shown in Figures 8A-8F, each strap chute 400 includes spaced-apart first and second upstanding legs, an upper connecting portion that spans the first and second legs and is positioned in the carriage 300, and a lower connecting portion that spans the first and second legs and is positioned in the load supporter 200. A strapping area is defined between the load supporter 200 and the carriage 300 and is encircled by the strap chutes 400a-400f. In this example embodiment, the radially inward walls of each strap chute 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 that strap chute. When the corresponding strapping head 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 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.

[0023] Each strapping head 500a-500f is configured to form an individual tensioned strap loop around the load by feeding the strap through its associated strap chute 400a-400f, holding the leading end of the strap while retracting the strap to remove it from the strap chute 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, each strapping head 500a-500f is a modular strapping head including independently removable and replaceable feed, tensioning, and sealing assemblies 510a-510f, 520a-520f, and 530a-530f, respectively. The strap-feeding assemblies 510a-510f,which are configured to feed and retract the strap, and the strap-tensioning assemblies 520a- 520f, which are configured to tension the strap, are mounted to a frame of the corresponding strap supply 600a-600f The carriage 300 supports the strap-sealing modules 530a-530f, which are 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 of a given strapping head 500 are located remote from the corresponding 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 carriage 300, or any other suitable component of the strapping machine 10).

[0024] This is merely one example strapping head, and the strapping machine 10 may include any suitable modular strapping heads or non-modular strapping heads (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 head and the type of strap. Certain strapping machines 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 machines 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 machines 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 machines 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.

[0025] Each strap supply 600a-600f includes a suitable frame (not labeled) that supports a strap-feeding assembly, a strap-tensioning assembly, and a coil of strap.

[0026] Each inlet chute 700a-700f connects a respective one of the strap-feeding assemblies 510a- 51 Of to its corresponding strap chute 400a-400f. In this example embodiment, each inlet chute includes a flexible tubular member that has an arch shape and defines a strappath between the respective strap-feeding assemblies 510a-510f and strap-sealing assemblies 530a-530f.

[0027] The first and second carriage-locking devices 900 and 1000 are operable with the first and second locking racks 800a and 800b to prevent the carriage 300 from descending. The first locking rack 800a, which is shown in Figures 2 and 6A-7D, includes a rectangular base 805a and multiple teeth 810a, 812a, 814a, and 816a (among other nonlabelled teeth) extending from the base 805a. Each tooth includes a planar contact surface extending substantially perpendicularly from the base 805a and an angled surface angularly extending from the end of the contact surface back toward the base 805a such that the tooth has a substantially triangular cross section (and in particular a cross-section of a right triangle). Here, the teeth 810a, 812a, 814a, and 816 have contact surfaces 810al, 812al, 814al, and 816al, respectively, and angled surfaces 810a2, 812a2, 814a2, and 816a2, respectively. The teeth are arranged adjacent to one another on the base 805a such that the teeth form a sawtooth pattern and such that a locking- tooth-receiving space having a triangular cross-section is defined between the contact and angled surfaces of adjacent teeth. Here, a locking-tooth-receiving space 81 la is defined between the teeth 810a and 812a, a locking-tooth-receiving space 813a is defined between the teeth 812a and 814a, and a locking-tooth-receiving space 815a is defined between the teeth 814a and 816a. The first locking rack 800a is mounted to the first leg 120 of the frame 100. The first locking rack 800a is oriented such that the base 805a is substantially vertical, the teeth extend toward the carriage 300 (and in particular the first carriage-locking device 900 on the carriage 300), and the contact surfaces 812al of the teeth are substantially horizontal and above their corresponding angled surfaces 812a2. These are merely one example of the teeth, and they may have any other suitable shape and configuration in other embodiments.

[0028] The second locking rack 800b, which is shown in Figure 2, is identical to the first locking rack 800a and includes a rectangular base and multiple teeth extending from the base. Each tooth includes a planar contact surface (not labeled) extending substantially perpendicularly from the base and an angled surface (not labeled) angularly extending from the end of the contact surface back toward the base such that the tooth has a substantially triangular cross section (and in particular a cross-section of a right triangle). The teeth are arranged adjacent to one another on the base such that the teeth form a sawtooth pattern and such that a locking-tooth-receiving space (not shown) having a triangular cross-section is formed betweenthe contact and angled surfaces of adjacent teeth. The second locking rack 800b is mounted to the second leg 130 of the frame 100. The second locking rack 800b is oriented such that the base is substantially vertical, the teeth extend toward the carriage 300 (and in particular the second carriage-locking device 1000 on the carriage 300), and the contact surfaces of the teeth are substantially horizontal and above their corresponding angled surfaces. These are merely one example of the teeth, and they may have any other suitable shape and configuration in other embodiments.

[0029] The first carriage-locking device 900, which is shown in Figures 2 and 4A- 7D, includes a locking-device housing 900h, first and second mounting bolts 910a and 910b, a spacer 912, a lock 920, a collar 932, a lock-mounting shaft 934, a first retainer 936, a second retainer 938, a biasing-element mount 942, an engaged element 944, a lock-biasing element 956, a lock mover 960, a first locking-device actuator 970, a lock-mover-mounting shaft 982, a first sensor SI, a second sensor S2, and a third sensor S3.

[0030] The locking-device housing 900h supports and / or at least partially encloses certain components of the first carriage-locking device 900. The locking-device housing 900h includes a first side panel 901, a second side panel 903, and a stop 909. The first and second mounting bolts 910a and 910b extend between and connect the first and second side panels 901 and 903. The spacer 912, which has a tubular shape in this example embodiment, circumscribes part of the second mounting bolt 910b that is positioned between the first and second side panels 901 and 903. The stop 909 is connected to and extends between the first and second side panels 901 and 903 via suitable fasteners or in any other suitable manner.

[0031] The lock 920 includes a lock body 922 defining a bore 922o therethrough, a locking tooth 924 including an engagement surface 924s and extending from a side of the lock body 922, spaced-apart first and second upper mounting ears 926a and 926b extending from the top of the lock body 922, and spaced-apart first and second lower mounting ears 928a and 928b extending from the bottom of the lock body 922. In this example embodiment, the lower mounting ears are part of a bracket attached to the lock body via fasteners, but they may be integrally formed with the lock body in other embodiments. The biasing-element mount 942, which is a pin in this example embodiment, is mounted to and extends between the first and second lower mounting ears 928a and 928b. The engaged element 944, which is a pin in thisexample embodiment, is mounted to and extends between the first and second upper mounting ears 926a and 926b.

[0032] The lock 920 is pivotably mounted within the locking-device housing 900h via the collar 932, the lock-mounting shaft 934, and the first and second retainers 936 and 938. Specifically, the collar 932, which has a tubular shape in this example embodiment, is press-fit within the bore 922o of the lock body 922. The lock-mounting shaft 934 extends through the collar 932 and through respective bores defined through the first and second side panels 901 and 903 of the locking-device housing 900h such that the ends of the lock-mounting shaft 934 protrude from the first and second side panels. The first and second retainers 936 and 938, which are retaining rings in this example embodiment, are fit into grooves around the protruding ends of the lock-mounting shaft 934 to retain it in place.

[0033] Once mounted within the locking-device housing 900h, the lock 920 is pivotable about a lock-pivot axis A920 — which is coaxial with the longitudinal axis of the lockmounting shaft 934 — between: (1) an engaged position, shown in Figure 5A, in which the locking tooth 924 projects from the locking-device housing 900h; and (2) a disengaged position, shown in Figure 5B, in which the locking tooth 924 is substantially retracted within the lockingdevice housing. The stop 909 and the sleeve 912 are sized, shaped, oriented, positioned, and otherwise configured to stop and prevent further pivoting of the lock 920 after it reaches the engaged position and the disengaged position, respectively. As shown in Figure 5A, the stop 909 is positioned to be engaged by the first and second upper mounting ears 926a and 926b when the lock 920 is in the engaged position and afterwards to prevent further pivoting of the lock 920 in that direction (clockwise from the perspective shown in Figure 5A). As best shown in Figure 5B, the sleeve 912 is positioned to be engaged by the first and second upper mounting ears 926a and 926b when the lock 920 is in the disengaged position and afterwards to prevent further pivoting of the lock 920 in that direction (counterclockwise from the perspective shown in Figure 5B).

[0034] The lock 920 is sized, shaped, mounted to the locking-device housing 900h, and otherwise configured such that it has a center of mass COM920 — shown in Figures 5A and 5B — positioned to enable gravity to bias the lock 920 to the engaged position. In this example embodiment, the center of mass COM920 is positioned beneath the lock-pivot axis A920 and on a side of the lock-pivot axis A920 opposite the locking tooth 924 when the lock 920 is in its engaged and disengaged positions.

[0035] The lock-biasing element 956 also biases the lock 920 to the engaged position. Specifically, the lock-biasing element 956, which is an extension spring in this example embodiment but may be any other suitable biasing element, is connected to and extends between the first mounting bolt 910a and the biasing-element mount 942. These components are positioned and the spring constant of the lock-biasing element 956 is selected such that the lockbiasing element 956 exerts a biasing force — and in this illustrated embodiment a pulling force — that biases the lock 920 to the engaged position (in addition to gravity as explained above).

[0036] The first locking-device actuator 970 is configured to move the lock mover 960 to force the lock 920 to move from the engaged position to the disengaged position. The lock mover 960 includes a tubular body 962 and a curved finger 964 extending from the body 962 and including a contact surface 964s. The first locking-device actuator 970 — which is an electric motor in this example embodiment but may be any other suitable actuator in other embodiments — includes an actuator housing 972 and an actuator output shaft 974 extending from the actuator housing 972. The first locking-device actuator 970 is configured to rotate the actuator output shaft 974.

[0037] The lock-mover-mounting shaft 982 is fit into a bore defined through the body 962 of the lock mover 960. The perimeter of the lock-mover-mounting shaft 982 and the corresponding perimeter of the bore are shaped such that the lock-mover-mounting shaft 982 is fixed in rotation with the lock mover 960. The actuator housing 972 of the first locking-device actuator 970 is mounted to the second side panel 903 of the locking-device housing 900h such that the actuator output shaft 974 extends through a suitable opening in the second side panel 903 and is received in a bore defined in the lock-mover mounting shaft 982. The actuator output shaft 974 is fixed in rotation with the lock-mover-mounting shaft 982 — and, therefore, the lock mover 960 is fixed in rotation with the lock-mover-mounting shaft 982 — via set screws 984, though any other suitable manner of fixing these components in rotation (such as a keyed connection or a non-circular perimeter shape) may be employed in other embodiments. A fastener 986 and a washer 988 are attached to the lock-mover-mounting shaft 982 on the side opposite the actuator output shaft 974 to prevent lateral movement of the components. The lock mover 960 is positioned such that the finger 964 is positioned between the first and second upper mounting ears 926a and 926b of the lock 920.

[0038] The first locking-device actuator 970 is configured to pivot the lock mover 960 about a lock-mover pivot axis A960 — which is coaxial with the longitudinal axis of the actuator output shaft 974 — from a first position shown in Figure 5A to a second position shown in Figure 5B to force the lock 920 to move from the engaged position to the disengaged position and to hold the lock mover 960 in the second position (and, therefore, hold the lock 920 in the disengaged position). The contact surface 964s of the finger 964 of the lock mover 960 is adjacent to (and in this example embodiment contacts) the engaged element 944 on the lock 920 when the lock 920 is in the engaged position and the lock mover 960 is in the first position. The first locking-device actuator 970 is energized (powered on) to exert a torque on the actuator output shaft 974 in a first rotational direction (clockwise from the perspective shown in Figures 5A and 5B) to rotate the actuator output shaft 974 — and the lock-mover-mounting shaft 982 and the lock mover 960 fixed in rotation with the actuator output shaft 974 — in the first rotational direction. As this occurs, the contact surface 964s of the finger 964 of the lock mover 960 exerts a force (here, a pushing force) on the engaged element 944 that causes the lock 920 to pivot toward the disengaged position. Eventually, as shown in Figure 5B, the first stop 952 stops the lock 920 from moving once the lock 920 reaches the disengaged position and the lock mover 960 reaches the second position. So long as the first locking-device actuator 970 remains energized, it continues to exert the torque on the actuator output shaft 974 and to hold the lock mover 960 in the second position and the lock 920 in the disengaged position.

[0039] The first locking-device actuator 970 is configured to enable the lock 920 to move from the disengaged position to the engaged position via the biasing forces imparted on the lock 920 by gravity (via the position of its center of mass COM920) and the lock-biasing element 956. In this example embodiment, the first locking-device actuator 970 is configured to — when deenergized — be driven in reverse to enable the lock 920 to move from the disengaged position to the engaged position and the lock mover 960 to move from the second position to the first position. Specifically, when the first locking-device actuator 970 is deenergized with the lock 920 in the disengaged position and the lock mover 960 in the second position, the first lockingdevice actuator 970 stops exerting the torque on the actuator output shaft 974. When this occurs, the biasing forces exerted on the lock 920 overcome any resistive force exerted by the lockingdevice actuator 970 and force the lock 920 to move back to its engaged position and the lockmover 960 to move back to its first position (via a force exerted on the contact surface 964s of the finger 964 of the lock mover 960 by the engaged element 944).

[0040] More specifically, the center of mass COM920 is positioned such that a first biasing torque is exerted by gravity on the on the lock 920 when the lock is in the disengaged position that biases the lock 920 to the engaged position. The lock-biasing element 956 exerts a second biasing torque on the lock 920 when the lock is in the disengaged position that biases the lock 920 to the engaged position. Any resistive torque exerted by the locking-device actuator 970 on the lock 920 when the locking-device actuator 970 is deenergized is less than the combined first and second biasing torques. Additionally, the center of mass COM920 is positioned such that a third biasing torque is exerted by gravity on the on the lock 920 when the lock is in the engaged position that biases the lock 920 to the engaged position. The lock-biasing element 956 exerts a fourth biasing torque on the lock 920 when the lock is in the engaged position that biases the lock 920 to the engaged position. Any resistive torque exerted by the locking-device actuator 970 on the lock 920 when the locking-device actuator 970 is deenergized is less than the combined third and fourth biasing torques. The third biasing force is less than the first biasing torque, and the fourth biasing force is less than the second biasing torque.

[0041] The first sensor SI is attached to the locking-device housing 900h, such as via a suitable bracket and fastener, and is positioned and configured to detect the teeth of the locking rack 800a as the first carriage-locking device 900 ascends and descends with the carriage 300. The second sensor S2 is attached to the locking-device housing 900h, such as via a suitable bracket and fastener, and is positioned and configured to detect when the lock 900 is in the disengaged position by detecting one of the first and second upper mounting ears 926a and 926b (or any other suitable component). The third sensor S3 is attached to the locking-device housing 900h, such as via a suitable bracket and fastener, and is positioned and configured to detect when the lock 900 is in the engaged position by detecting one of the first and second lower mounting ears 928a and 928b (or any other suitable component). The one or more sensors S may be any suitable type of sensor, such as mechanical proximity sensors, capacitive proximity sensors, inductive proximity sensors, magnetic proximity sensors, optical proximity sensors, and / or ultrasonic proximity sensors.

[0042] As shown in Figures 2 and 6A-7D, the first carriage-locking device 900 is mounted to the carriage 300 adjacent the first locking rack 800a and such that the locking tooth924 extends toward the teeth of the first locking rack 800a when the lock 920 is in the engaged position. Each locking-tooth-receiving space defined between adjacent teeth of the first locking rack 800a is sized to receive part of the locking tooth 924a of the lock 920 when the lock 920 is in the engaged position. Additionally, when the lock 920 is in the engaged position and the locking tooth 924 is received in one of the locking-tooth-receiving spaces, the engagement surface 924s of the locking tooth 924 is positioned to contact the contact surface of one of the teeth and prevent the carriage 300 from descending. Conversely, when the lock 920 is in the disengaged position, the locking tooth 924 is removed from the locking-tooth-receiving spaces and positioned so as not to prevent the carriage 300 from descending.

[0043] The second carriage-locking device 1000 is a mirror image of and functions in the same manner as the first carriage-locking device 900 and is not described in further detail. The second carriage-locking device 1000 includes a second locking-device actuator 1070 that is shown in Figure 3.

[0044] As shown in Figure 2, the second carriage-locking device 1000 is mounted to the carriage 300 adjacent the second locking rack 800b and such that the locking tooth of the lock of the second carriage-locking device extends toward the teeth of the second locking rack 800b when the lock is in the engaged position. Each locking-tooth-receiving space defined between adjacent teeth of the second locking rack 800b is sized to receive part of the locking tooth of the lock when the lock is in the engaged position. Additionally, when the lock is in the engaged position and the locking tooth is received in one of the locking-tooth-receiving spaces, the engagement surface of the locking tooth is positioned to contact the contact surface of one of the teeth and prevent the carriage 300 from descending. Conversely, when the lock is in the disengaged position, the locking tooth is removed from the locking-tooth-receiving spaces and positioned so as not to prevent the carriage 300 from descending.

[0045] The controller 2000 includes a processing device or devices communicatively connected to a memory device or devices. For instance, the controller is a programmable logic controller in certain embodiments. 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 strapping machine 10.

[0046] The controller 2000 is communicatively and operably connected to the carriage actuator 350, the strapping heads 500a-500f, the first and second locking-device actuators 970 and 1070, and the sensors S1-S3 to receive signals from and / or to control those components.

[0047] The controller 2000 is configured to control the first and second lockingdevice actuators 970 and 1070 in several ways during operation of the strapping machine 10. Initially, when the strapping machine 10 is deenergized (powered off), the locks of the first and second carriage-locking devices 900 and 1000 are in their respective engaged positions and engaging the contact surfaces of teeth of the respective first and second locking racks 800a and 800b to suspend the carriage 300 and prevent it from descending. Once the strapping machine 10 is energized (powered on) or otherwise receives a platen-unlock instruction, such as responsive to an input from the operator, the locks must be moved to their respective disengaged positions to enable the carriage 300 to descend so the strapping machine 10 can carry out strapping processes. To do so, the controller 2000 controls the carriage actuator 350 to raise the carriage 300 until the first sensors of the first and second carriage-locking devices 900 and 1000 detect a tooth of the first and second locking racks 800a and 800b, respectively. The controller 2000 then controls the first and second locking-device actuators 970 and 1070 (e.g., by energizing them) to move their respective locks to their respective disengaged positions and hold them there. Specifically, the controller 2000 controls the first and second locking-device actuators 970 and 1070 to move the locking devices until the second sensors of the first and second carriagelocking devices detect their respective locks, at which point the controller 2000 controls the first and second locking-device actuators 970 and 1070 to hold the locks in place. The carriage 300 is then movable upwards and downwards without interference from the locking-device actuators, and the strapping machine 10 is ready to carry out strapping processes. In certain embodiments,the controller 2000 prevents operation of the strapping machine 10 until receiving feedback from the one or more sensors S indicating that the locks are in their respective disengaged positions.

[0048] Figures 6A-6C show this process for the first carriage-locking device 900. Figure 6A shows the engagement surface 924s of the locking tooth 924 of the lock 920 engaging the engagement surface 810al of the tooth 810a of the first locking rack 800. Figure 6B shows the first carriage-locking device 900 positioned so the first sensor SI detects the tooth 814a of the first locking rack 800a. At this point, the lock 920 is between its engaged and disengaged positions. This occurs passively via the locking tooth 924 contacting the angled surface 812a2 of the tooth 812 as the first carriage-locking device 900 ascends with the carriage 300 relative to the first locking rack 800a. Figure 6C shows the lock 920 after it has been moved completely to the disengaged position by the first locking-device actuator 970 responsive to the first sensor SI detecting the tooth 814a.

[0049] When the controller 2000 receives a platen-lock instruction, such as responsive to an input from the operator to deenergize the strapping machine 10 or the actuation of an emergency-stop button of the strapping machine 10, the controller 2000 controls the first and second carriage-locking devices 900 and 1000 to do so. Specifically, if the first sensors of the first and second carriage-locking devices 900 and 1000 already detect teeth of the first and second locking racks 800a and 800b, respectively, the controller 2000 controls the carriage actuator 350 to stop moving the carriage 300. If the first and second sensors of the first and second carriage-locking devices 900 and 1000 do not already detect teeth of the first and second locking racks 800a and 800b, respectively, the controller 2000 controls the carriage actuator 350 to raise the carriage 300 until they do so and then controls the carriage actuator 350 to stop moving the carriage 300. The controller 2000 deenergizes (or otherwise controls) the first and second locking-device actuators 970 and 1070 to enable the respective biasing forces (exerted by gravity and the lock-biasing element) to move the locks to their respective engaged positions. The controller 2000 then controls the carriage actuator 350 to lower the carriage 300 until the third sensors of the first and second locking carriage-locking devices S3 detect their respective locks, at which point the locking teeth of the locks engage the teeth of the respective locking racks 800a and 800b and suspend the carriage 300.

[0050] Figures 7A-7D show this process for the first carriage-locking device 900. Figure 7A shows the lock 920 in the disengaged position and the sensor SI not detecting a toothof the locking rack 800a when a platen-lock instruction is received. Figure 7B shows the first carriage-locking device 900 after it has ascended until the first sensor SI detects the tooth 816a of the locking rack 800a. Figure 7C shows the first carriage-locking device 900 in the same position as in Figure 7B, but with the first locking-device actuator 970 deenergized and the lock 920 partially between its engaged and disengaged positions. Figure 7D shows the first carriagelocking device 900 after it has descended further such that the lock 920 is in its engaged position and the locking tooth 924 is engaging the contact surface 812al of the tooth 812a.

[0051] The first and second carriage-locking devices 900 and 1000 are also configured to automatically suspend the carriage 300 if the strapping machine 10 is deenergized (such as due to a power outage) when the carriage 300 is not suspended. In this scenario, when the strapping machine 10 is deenergized, the carriage actuator 350 and the first and second locking-device actuators 970 and 1070 are deenergized. As explained above, when the lockingdevice actuators are deenergized, gravity and the lock-biasing element force the locks to move to their respective engaged positions. The carriage actuator 350 includes an integrated brake that prevents the carriage 300 from moving (descending) when the carriage actuator 350 is deenergized. But if the brake fails, the carriage 300 will descend via gravity and, eventually, the locks will engage the teeth of the first and second locking racks 800a and 800b to stop the carriage 300 from descending and suspend it.

[0052] The packaging machine of the present disclosure — and particularly the carriage-locking devices and associated locking racks — solve the above problems. Unlike existing suspension brackets, the carriage-locking devices and locking racks enable suspension of the carriage at any vertical position. This speeds the deenergizing process and provides more flexibility for operators and service technicians who may desire the carriage to be suspended at different heights depending on the situation. The carriage-locking devices and locking racks also act as a failsafe that stops and suspends the carriage following unexpected deenergizing of the packaging machine and failure of the brake of the carriage actuator. Finally, the carriage-locking devices are electronically controlled and do not require the operator to manually move any components into place to suspend the carriage.

[0053] Operation of the strapping machine 10 to carry out a strapping process is now described in conjunction with Figures 8A-8F. First, a load L is moved onto the support surface 210 of the load supporter 200 beneath the carriage 300, as shown in Figure 8 A. The controller2000 controls the carriage actuator 350 to move the carriage 300 downward into engagement with the top surface of the load L and partially compresses the load L, as shown in Figure 8B. The controller 2000 then controls the strapping heads 500a-500f to carry out a strap-feeding process by controlling each strap-feeding assembly 510a-510f to feed strap S from its respective strap supplies 600a-600f, through its respective inlet chute 700a-700f, and into and around its respective strap chute 400a-400f and then controlling the respective strap-sealing assemblies 530a-530f to hold the leading ends of the strap, as shown in Figure 8C. The controller 2000 then controls the strapping heads 500a-500f to carry out a strap-retraction process by controlling each strap-feeding assembly 510a-510f to retract its respective strap S such that the strap S exits its respective strap chute 400a-400f and moves radially inwardly into engagement with the load L, as shown in Figure 8D. The controller 2000 then controls the strapping heads 500a-500f to carry out a strap-tensioning process by controlling each strap-tensioning assembly 520a-520f to tension its respective strap S to a designated tension. The controller 2000 then controls the strapping heads 500a-500f to carry out a strap-sealing process by controlling each strap-sealing assembly 530a-530f to attach two portions of its respective 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 8E. The controller 2000 then controls the carriage actuator 350 to raise the carriage 300 until the carriage 300 no longer contacts the load L, as shown in Figure 8F, completing the strapping process.

[0054] In the above example embodiment, the locking racks are separate from and in addition to the racks used in the rack-and-pinion assembly for raising and lowering the carriage. In other embodiments, the racks used in the rack-and-pinion assembly for raising and lower the carriage are also used as the locking racks. In these embodiments, the carriage-locking devices are oriented appropriately such that their locking teeth extend toward the teeth of the racks when in their engaged positions.

[0055] In the above example embodiment, the packaging machine includes two carriage-locking devices and locking racks. In other embodiments, the packaging machine includes only one carriage-locking device and locking rack or more than two carriage-locking devices and locking racks.

[0056] Other embodiments of the carriage-locking devices do not include the lockbiasing element. In these embodiments, the torque imposed on the lock by gravity (via the position of the center of mass of the lock) biases the lock to the engaged position.

Claims

Claims1. A packaging machine comprising: a load supporter; a rack comprising a base and multiple teeth extending from the base; a carriage vertically movable relative to the rack and the load supporter; a carriage actuator operably connected to the carriage to vertically move the carriage; and a carriage-locking device supported by and movable with the carriage, the carriage-locking device comprising a lock movable between an engaged position and a disengaged position, wherein when the lock is in the engaged position, the lock is positioned to contact one of the teeth of the rack and prevent the carriage from descending toward the load supporter, wherein when the lock is in the disengaged position, the lock is positioned not to prevent the carriage from descending toward the load supporter.

2. The packaging machine of claim 1, wherein the carriage-locking device further comprises a locking-device actuator operably connected to the lock and configured to move the lock from the engaged position to the disengaged position.

3. The packaging machine of claim 2, wherein the locking-device actuator comprises an electric motor.

4. The packaging machine of claim 2, wherein the locking-device actuator is further configured to hold the lock in the disengaged position.

5. The packaging machine of claim 4, further comprising a controller operably connected to the locking-device actuator and configured to control the locking-device actuator to move the lock from the engaged position to the disengaged position and to hold the lock in the disengaged position.

6. The packaging machine of claim 5, wherein the lock is biased to the engaged position.

7. The packaging machine of claim 6, further comprising a biasing element biasing the lock to the engaged position.

8. The packaging machine of claim 6, wherein the lock is pivotable between the engaged position and the disengaged position, wherein the lock is configured such that a center of mass of the lock is positioned such that gravity biases the lock to the engaged position.

9. The packaging machine of claim 8, wherein the lock is pivotable about a lockpivot axis, wherein the rack is positioned on a first side of the lock-pivot axis and oriented transverse to the lock-pivot axis, wherein the center of mass of the lock is positioned on a second side of the lock-pivot axis opposite the first side, wherein the center of mass of the lock is positioned closer than the lock pivot axis to the load supporter.

10. The packaging machine of claim 5, wherein the carriage-locking device further comprises a lock mover movable from a first position to a second position to move the lock from the engaged position to the disengaged position, wherein the locking-device actuator is operably connected to the lock mover to move the lock mover from the first position to the second position to move the lock from the engaged position to the disengaged position.

11. The packaging machine of claim 10, wherein the lock is pivotable about a lockpivot axis between the engaged position and the disengaged position, wherein the lock mover is pivotable about a lock-mover pivot axis between the first and second positions, wherein the lock mover is positioned to contact the lock when moving from the first position to the second position to force the lock to move from the engaged position to the disengaged position.

12. The packaging machine of claim 11, wherein the lock comprises a lock body, a locking tooth extending from the lock body, and a pin connected to the lock body, wherein the lock mover is positioned to contact the pin when moving from the first position to the second position.

13. The packaging machine of claim 1 1, wherein the locking-device actuator comprises an electric motor comprising a rotatable output shaft, wherein the lock mover is fixed in rotation with the output shaft.

14. The packaging machine of claim 5, wherein the lock is biased to the engaged position, wherein the locking-device actuator is further configured to enable the lock to automatically move from the disengaged position to the engaged position when the lockingdevice actuator is deenergized.

15. The packaging machine of claim 14, wherein the lock is pivotable between the engaged position and the disengaged position, wherein the lock is configured such that a center of mass of the lock is positioned such that a first biasing torque is exerted on the lock when the lock is in the disengaged position that biases the lock to the engaged position.

16. The packaging machine of claim 15, further comprising a biasing element exerting a second biasing torque on the lock when the lock is in the disengaged position that biases the lock to the engaged position.

17. The packaging machine of claim 16, wherein any resistive torque exerted by the locking-device actuator on the lock when the locking-device actuator is deenergized is less than the combined first and second biasing torques.

18. The packaging machine of claim 17, wherein the lock is further configured such that the center of mass of the lock is positioned such that a third biasing torque is exerted on the lock when the lock is in the engaged position that biases the lock to the engaged position, wherein the biasing element exerts a fourth biasing torque on the lock when the lock is in the engaged position that biases the lock to the engaged position, wherein any resistive torque exerted by the locking-device actuator on the lock when the locking-device actuator is deenergized is less than the combined third and fourth biasing torque.

19. The packaging machine of claim 18, wherein the carriage-locking device further comprises a first stop and a second stop, wherein the first stop is positioned to prevent furtherpivoting of the lock when the lock reaches the engaged position, wherein the second stop is positioned to prevent further pivoting of the lock when the lock reaches the disengaged position.

20. The packaging machine of claim 1, wherein the carriage comprises one of: (a) at least part of a strapping head configured to apply strap to a load; (b) a film carriage configured to support a roll of film; and (c) multiple reefing fingers configured to gather, stretch, and dispense a hood of plastic stretch film.

21. The packaging machine of claim 1, wherein the carriage-locking device further comprises (a) a locking-device actuator operably connected to the lock and configured to move the lock from the engaged position to the disengaged position and to hold the lock in the disengaged position and (b) a sensor configured to detect the teeth of the rack, wherein the packaging machine further comprises a controller configured to, responsive to receiving a platen-unlock instruction when the lock is in the engaged position and engaging a first one of the teeth of the rack: control the carriage actuator to raise the carriage; and responsive to the sensor detecting a second one of the teeth of the rack that is positioned above the first one of the teeth of the rack, control the locking-device actuator to move the lock from the engaged position to the disengaged position and to hold the lock in the disengaged position.

22. The packaging machine of claim 1, wherein the carriage-locking device further comprises (a) a locking-device actuator operably connected to the lock and configured to move the lock from the engaged position to the disengaged position and to hold the lock in the disengaged position and (b) a sensor configured to detect the teeth of the rack, wherein the packaging machine further comprises a controller configured to, responsive to receiving a platen-lock instruction when the lock is in the disengaged position and the sensor is not detecting one of the teeth of the rack: control the carriage actuator to raise the carriage; and responsive to the sensor detecting a first one of the teeth of the rack, control the locking-device actuator to enable the lock to move from the disengaged position to the engaged position and control the carriage actuator to lower the carriage until thelock engages a second one of the teeth of the rack that is positioned below the first one of the teeth of the rack.

23. The packaging machine of claim 22, wherein the controller is further configured to, responsive to receiving a platen-unlock instruction when the lock is in the engaged position and engaging a third one of the teeth of the rack: control the carriage actuator to raise the carriage; and responsive to the sensor detecting a fourth one of the teeth of the rack that is positioned above the third one of the teeth of the rack, control the locking-device actuator to move the lock from the engaged position to the disengaged position and to hold the lock in the disengaged position.

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