Wrapping machine

Abstract

The present disclosure provides a film carriage for a wrapping machine. The film carriage includes a film-carriage frame, a first prestretch roller rotatably mounted to the film-carriage frame, a third prestretch roller rotatably mounted to the film-carriage frame, and a roller support including a roller-support frame and a second prestretch roller rotatably mounted to the roller¬ support frame. A first space is defined between the first and third prestretch rollers. The roller support is movable relative to the film-carriage frame between a closed position in which the second prestretch roller at least partially occupies the first space and an open position in which the second prestretch roller is removed from the first space.

Description

WRAPPING MACHINEPriority

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 567,688, filed March 20, 2024, the entire contents of which is incorporated herein by reference.Field

[0002] The present disclosure relates to stretch-wrapping machines, and more particularly to stretch-wrapping machines that include prestretch rollers.Background

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

[0004] Certain stretch-wrapping machines include prestretch assemblies that prestretch the film along its longitudinal axis after it is pulled off of the film roll and before it is applied to the load. Prestretching the film before applying it to the load has several benefits, including increasing the film’s containment force and extending the longevity of the film roll. One known prestretch assembly includes an upstream prestretch roller, a downstream pre- stretch roller, and a prestretch-drive assembly operably connected to the upstream and downstreamprestretch rollers to rotate them. The downstream prestretch roller has a diameter that is larger than the diameter of the upstream prestretch roller. The pre stretch-drive assembly drives the prestretch rollers so the downstream prestretch roller has a higher linear speed than the upstream prestretch roller. The linear speed (alternatively called the tangential speed) of a roller is a function of its diameter and its rotational speed and corresponds to the speed of the film contacting the roller. This linear speed differential results in the downstream prestretch roller imposing a stretching force on the film, resulting in the film stretching after it disengages the upstream prestretch roller and travels onto the downstream prestretch roller. The difference in the diameters of the prestretch rollers enables the prestretch assembly to achieve a relatively high prestretch.Summary

[0005] Various embodiments of the present disclosure provide a film carriage for a wrapping machine. The film carriage includes a film-carriage frame, a first prestretch roller rotatably mounted to the film-carriage frame, a third prestretch roller rotatably mounted to the film-carriage frame, and a roller support including a roller-support frame and a second prestretch roller rotatably mounted to the roller-support frame. A first space is defined between the first and third prestretch rollers. The roller support is movable relative to the film-carriage frame between a closed position in which the second prestretch roller at least partially occupies the first space and an open position in which the second prestretch roller is removed from the first space.Brief Description of the Figures

[0006] Figure l is a perspective view of one example embodiment of a stretchwrapping machine of the present disclosure.

[0007] Figure 2 is a block diagram showing certain components of the stretchwrapping machine of Figure 1.

[0008] Figure 3 is a perspective view of the film carriage of the wrapping assembly of the stretch-wrapping machine of Figure 1.

[0009] Figure 4 is a top plan view of the rollers of the film carriage of Figure 3.

[0010] Figure 5 is a perspective view of part of the film carriage of Figure 3 with certain components removed to show the prestretch-drive assembly.

[0011] Figures 6A and 6B are front and rear perspective views of the roller support of the film carriage of Figure 3.

[0012] Figures 7A, 7B, and 7C are perspective views of part of the film carriage of Figure 3, including the roller support and the roller-support guide, with the roller support in the closed position, partially open position, and open position, respectively.

[0013] Figures 8 A, 8B, and 8C are side elevational views corresponding to Figures7A, 7B, and 7C.

[0014] Figures 9A, 9B, and 9C are cross-sectional side elevational views of part of the film carriage of Figure 3 taken substantially along line 9-9 of Figure 7A with the roller support in the closed position, partially open position, and open position, respectively.

[0015] Figures 10A, 10B, and 10C are cross-sectional top plan views of part of the film carriage of Figure 3 taken substantially along line 10-10 of Figure 7A with the roller support in the closed position, partially open position, and open position, respectively.

[0016] Figure 11 A is a cross-sectional side elevational view of part of the film carriage of Figure 3 taken substantially along line 11-11 of Figure 6A with the handle and the locking assembly in their respective locked positions.

[0017] Figure 1 IB is similar to Figure 11A, but with the handle and the locking assembly in their respective unlocked positions.

[0018] Figure 12A-12C are top plan views of the prestretch rollers and the idler rollers of the film carriage of Figure 3 and show replacement of an empty film roll with a new film roll.

[0019] Figure 13 is a perspective view of another embodiment of the film carriage of the present disclosure that includes an automatic-opening-and-closing assembly.Detailed Description

[0020] 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.

[0021] Figures 1 and 2 show one embodiment of the wrapping machine 1 of the present disclosure and components thereof. The wrapping machine 1 includes a wrappingmachine frame 10, a circular guide 20, a guide actuator 20a, a wrapping assembly 40, a cutting- and-sealing device (not shown), an operator interface 1000, and a controller C.

[0022] The wrapping-machine frame 10 is formed from multiple components j oined together and configured to support the other components of the wrapping machine 1. The wrapping-machine frame 10 defines a wrapping area within its interior and has an infeed area 10a at which a load — such as a load L on a pallet P — is conveyed via a conveyor into the wrapping area for wrapping and an outfeed area 10b at which the load is conveyed from the wrapping area after wrapping. The illustrated wrapping-machine frame 10 is merely one example configuration, and any suitable configuration can be employed.

[0023] The circular guide 20 serves as the mount for the wrapping assembly 40 and is movably mounted to the wrapping-machine frame 10 (such as to one or more vertical members of the wrapping-machine frame 10) such that the circular guide 20 is vertically movable relative to the wrapping-machine frame 10 between an upper position and a lower position. The guide actuator 20a is operably connected to the circular guide 20 to move the circular guide 20 relative to the wrapping-machine frame 10 between the upper and lower positions. In certain embodiments, the guide actuator 20a includes one or more electric motors operably connected to the circular guide 20 via one or more belt-and-pulley assemblies to move the circular guide 20 between the upper and lower positions. In other embodiments, the guideactuator 20a includes one or more pneumatic or hydraulic actuators operably connected to the circular guide 20 to move the circular guide 20 between the upper and lower positions. These are merely examples, and the guide actuator 20a can include any suitable actuator configured to move the circular guide 20 between the upper and lower positions.

[0024] The wrapping assembly 40 is movably mounted to the circular guide 20 such that the wrapping assembly 40 is rotatable relative to the circular guide 20. The wrapping assembly 40 includes a ring-shaped support (not shown), a film carriage 100, and a wrappingassembly actuator 40a.

[0025] The ring-shaped support serves as the mount for the film carriage 100 and is movably mounted to the circular guide 20 such that the support — and the film carriage 100 and other components connected to the support — is rotatable relative to the circular guide 20. In this example embodiment, the support is movably mounted to the circular guide 20 via multiple spaced-apart rollers that are connected to the support and positioned on a track on the circular guide 20. The wrapping-assembly actuator 40a is operably connected to the support to rotate the support and components thereon relative to the circular guide 20 and the load L. In certain embodiments, the wrapping-assembly actuator 40a includes one or more motors operably connected to the wrapping assembly 40 via one or more belt-and-pulley assemblies to rotate the wrapping assembly 40 relative to the circular guide 20 and the load L. This is merely an example, and the wrapping-assembly actuator 40a can include any suitable actuator configured to rotate the wrapping assembly 40 relative to the circular guide 20 and the load L.

[0026] The film carriage 100 is fixedly connected to the support to move with the support, i.e., rotate relative to the circular guide 20 and move vertically relative to the wrappingmachine frame 10. The film carriage 100 is configured to rotatably support a replaceable roll R of film F (such as plastic stretch film), prestretch a web of the film FW after pulling it from the roll R, and apply the prestretched film web FW to the load as the film carriage 100 rotates around the load. The film carriage 100 includes: a film-carriage frame 110; a roller support 200; a roller-support guide 300; a set of rollers 400 including a first idler roller 402, a second idler roller 404, a first prestretch roller 406, a second prestretch roller 408, a third prestretch roller 410, a third idler roller 412, a fourth idler roller 414, a fifth idler roller 416, and a sixth idler roller 418; and a prestretch-drive assembly 430.

[0027] The film-carriage frame 110 serves as a support for the other components of the film carriage 100 and includes an upper support 112, a lower support 114, a first spacer 116, a second spacer 117, and a film-roll-support frame 118 including upper and lower rotatable filmroll engagers 119a and 119b. The first and second spacers 116 and 117 extend between, are transverse to, and are connected to the upper and lower supports 112 and 114. The film-roll- support frame 118 is connected to, is transverse to, and extends downward from the upper support 112.

[0028] The first idler roller 402, the first prestretch roller 406, the third prestretch roller 410, the fourth idler 414, the fifth idler roller 416, and the sixth idler roller 418 are supported by the film-carriage frame 110. Specifically, these rollers are rotatably mounted to the film-carriage frame 110, such as via suitable bearings, such that these rollers can rotate relative to the film-carriage frame 110. These rollers extend between the upper and lower supports 112 and 114 are oriented substantially parallel to one another and to the first and second spacers 116 and 117. The first, third, fourth, fifth, and sixth idler rollers 402, 414, 416, and 418 are freely rotatable, while the first and third prestretch rollers 406 and 410 are driven in rotation by the prestretch-drive assembly 430 as described below.

[0029] As used herein, “downstream” means the direction of travel of the film web FW as it is pulled off the roll R and through the rollers 400, and “upstream” means the opposite direction.

[0030] As best shown in Figure 4, the first idler roller 402 is positioned downstream of the film-roll engagers 119a and 119b such that the first idler roller 402 is the first roller the film web FW contacts after leaving the roll R. The first prestretch roller 406 has a first diameter and is positioned downstream of the first idler roller 402. The first idler roller 402 and the first prestretch roller 406 are spaced apart such that the second idler roller 404 can fit between them, as explained below. A first-prestretch-roller gear 406g is positioned atop of and fixed in rotation with the first prestretch roller 406 such that the two components rotate together. The outer surface of the first prestretch roller 406 can have a high-friction coating. The third prestretch roller 410 has a third diameter and is positioned downstream of the first prestretch roller 406. The third diameter is greater than (and in this particular example, about 2*) the first diameter of the first prestretch roller 406. The first and third prestretch rollers 406 and 410 are spaced apart such that the second prestretch roller can 408 fit between them, as explained below. The outersurface of the third prestretch roller 410 can have a high-friction coating. The fourth idler roller 414 is positioned downstream of the third prestretch roller 410. The third prestretch roller 410 and the fourth idler roller 414 are spaced apart such that the third idler roller 412 can fit between them, as explained below. The fifth idler roller 416 is positioned downstream of and spaced apart from the fourth idler roller 414, and the sixth idler roller 418 is positioned downstream of and spaced apart from the fifth idler roller 416.

[0031] The roller support 200, best shown in Figures 6A and 6B, serves as a support for the second idler roller 404, the second prestretch roller 408, and the third idler roller 412 and can move relative to the film-carriage frame 110 between closed and open positions to facilitate changing film rolls and to enable easy re-threading of the film between the rollers 400. The roller support 200 includes a roller-support frame 210, a lock actuator 230, and a lock 240.

[0032] The roller-support frame 210 serves as a support for the second idler roller 404, the second prestretch roller 408, the third idler roller 412, and the other components of the roller support 200. The roller-support frame 210 includes an upper support 212, a lower support 214, a first spacer 216, and a second spacer 218. The first and second spacers 216 and 218 extend between, are transverse to, and are connected to the upper and lower supports 212 and 214.

[0033] The second idler roller 404 is rotatably mounted, such as via suitable bearings, to one or more arms that are pivotably mounted to the roller-support frame 210 such that the second idler roller 404 can freely rotate relative to the roller-support frame 210. The second idler roller 404 is substantially parallel to the first and second spacers 216 and 218. The arms are spring-biased to force the second idler roller 404 toward the roller-support frame 210.

[0034] The second prestretch roller 408 is rotatably mounted to the roller-support frame 210, such as via suitable bearings, such that it can rotate relative to the roller-support frame 210. The second prestretch roller 408 extends between the upper and lower supports 212 and 214 and is oriented substantially parallel to the second idler roller 404 and to the first and second spacers 216 and 218. The second prestretch roller 408 has a second diameter, which is substantially the same as the first diameter of the first prestretch roller 406 in this example embodiment, is positioned downstream of the second idler roller 404. The second idler roller 404 and the second prestretch roller 408 are spaced apart such that the first prestretch roller 406 can fit between them, as explained below. A second-prestretch-roller gear 408g is positioned atop ofand fixed in rotation with the second prestretch roller 408 such that the two components rotate together. The outer surface of the second prestretch roller 408 can have a high-friction coating.

[0035] The third idler roller 412 is rotatably mounted, such as via suitable bearings, to one or more arms that are pivotably mounted to the roller-support frame 210 such that the third idler roller 412 can freely rotate relative to the roller-support frame 210. The third idler roller 412 is positioned downstream of the second prestretch roller 408 and is oriented substantially parallel to the second prestretch roller 408 and the first and second spacers 216 and 218. The third idler roller 412 and the second prestretch roller 408 are spaced apart such that the third prestretch roller 410 can fit between them, as explained below. The arms are spring-biased to force the third idler roller 412 toward the roller-support frame 210.

[0036] The lock actuator 230 includes a lock-actuator body 232, a handle 234 at an upper end of the lock-actuator body 232, stops 236 at a lower end of the lock-actuator body 232 and substantially parallel to the handle 234, and lock engagers 238 extending from the lockactuator body 232 transversely to the handle 234 and the stops 236. The lock actuator 230 is pivotably mounted to the first and second spacers 216 and 218 of the roller-support frame 210 via a shaft 230s having a longitudinal axis A230 such that the lock actuator 230 is pivotable relative to the roller-support frame 210 about the axis A230 between a locked position (Figure 11 A) and an unlocked position (Figure 1 IB).

[0037] As best shown in Figures 11 A and 1 IB, the lock 240 includes a rod 242, a hook 244 fixedly connected to an upper end of the rod 242, a pin 246 extending transversely through the rod 240, an upper collar 240c 1 slidably connected to the rod 242 and positioned below the hood 244, a lower collar 240c2 fixedly connected to the rod 242 below the upper collar 240cl, and a lock-biasing element 240s (which is a compression spring in this example embodiment) extending between and engaging the upper and lower collars 240c 1 and 240c2. The rod 242 is slidably mounted to the roller-support frame 210 and oriented substantially parallel to the first and second spacers 216 and 218. The pin 246 is positioned above the lock engagers 238. The lock 240 is movable — and in this example embodiment, translatable — between a locked position (Figure 11 A) and an unlocked position (Figure 1 IB).

[0038] The lock-biasing element 240s biases the lock 240 to the locked position and, because the pin 246 is above the lock engagers 238, biases the lock actuator 230 to the lockedposition. Accordingly, the lock actuator 230 is pivotable from the locked position to the unlocked position to move the lock 240 from the locked position to the unlocked position.

[0039] As best shown in Figures 9A-10C, the roller support 200 is pivotably mounted to the film-carriage frame 110 via first and second links 290a and 290b. Specifically, the lower ends of the first and second links 290a and 290b are pivotably connected to the first and second spacers 116 and 117, respectively, of the film-carriage frame 110 such that the first and second links 290a and 290b are pivotable relative to the film-carriage frame 110 about a first pivot axis A2ooa. The opposing upper ends of the first and second links 290 and 290b are pivotably connected to opposing ends of the upper support 212 of the roller-support frame 210 such that the roller support 200 is pivotable relative to the first and second links 290a and 290b about a second pivot axis A2oob, which is substantially parallel to the first pivot axis A2ooa. This connection thus enables the roller support 200 to move relative to the film-carriage frame 110 by pivoting about both the first and second pivot axes A2ooaand A2oob. As the roller support 200 pivots about the first pivot axis A2ooa, the second pivot axis A2oob pivots with the roller support 200 and translates slightly downward. Put more broadly, this the roller support 200 is movably mounted to the film-carriage frame 110 such that the roller support 200 can move relative to the film-carriage frame 110 in three degrees of freedom (two pivoting degrees of freedom and one translating degree of freedom).

[0040] The roller support 200 is pivotably mounted to the film-carriage frame 110 via the first and second links 290a and 290b such that the roller support 200 can move relative to the film-carriage frame 110 between a closed position and an open position. Figures 7A, 8A, 9A, and 10A show the roller support 200 in the closed position. When the roller support 200 is in the closed position, the rollers 400 are substantially parallel to one another. Additionally, the second idler roller 404 occupies the space between the first idler roller 402 and the first prestretch roller 406, the second prestretch roller 408 occupies the space between the first prestretch roller 406 and the third prestretch roller 410, and the third idler roller 412 occupies the space between the third prestretch roller 410 and the fourth prestretch roller 414. When the roller support 200 is in the closed position, the first-prestretch-roller gear 406g meshes with and drivingly engages the second-prestretch-roller gear 408g.

[0041] As shown in Figure 11A, when the roller support 200 is in the closed position and the lock 240 is in the locked position, the bottom end of the rod 242 of the lock 240 isreceived in an opening defined in a lock plate 1 14a attached to the lower support 1 14 of the filmcarriage frame 110, and the hook 244 engages a catch (not shown) attached to the upper support 112 of the film-carriage frame 110. This prevents the roller support 200 from moving away from the closed position. When the lock actuator 230 is moved to the unlocked position to move the lock 240 to the unlocked position, as shown in Figure 1 IB, the bottom end of the rod 242 is removed from the lock plate 114a, and the hook 244 is disengaged from the catch, which enables the roller support 200 to move away from the closed position.

[0042] Figures 7C, 8C, 9C, and 10C show the roller support 200 in the open position. When the roller support 200 is in the open position, the second idler roller 404, the second prestretch roller 408, and the third idler roller 412 are oriented transversely to the remaining rollers 400. Additionally, the second idler roller 404 is removed from the space between the first idler roller 402 and the first prestretch roller 406, the second prestretch roller 408 is removed from the space between the first prestretch roller 406 and the third prestretch roller 410, and the third idler roller 412 is removed from the space between the third prestretch roller 410 and the fourth prestretch roller 414. Additionally, when the roller support 200 is in the open position, the first-prestretch-roller gear 406g is unmeshed from the second-prestretch-roller gear 408g.

[0043] The roller-support guide 300, best shown in Figures 7A-7C, helps guide the roller support 200 as it moves between the open and closed positions. The roller-support guide 300 includes a first shaft 302, a second shaft 304, a third shaft 306, a first arm 310, a second arm 312, a first mount 322, and a second mount 324. The first shaft 302 is connected to the upper ends of and extends between the first and second arms 310 and 312. The first shaft 302 is fixed in rotation with the first and second arms 310 and 312. The third shaft 306 is rotatably connected to, such as via bearings, the lower ends of and extends between the first and second arms 310 and 312 such that the third shaft 306 can rotate relative to the first and second arms 310 and 312. The second shaft 304 is connected to and extends between the first and second arms 310 and 312 and is positioned between the first and third shafts 302 and 306. The first and second mounts 322 and 324 are rotatably mounted to the third shaft 306 such that the third shaft 306 is rotatable relative to the first and second mounts 322 and 324.

[0044] The first shaft 302 of the roller-support guide 300 is rotatably connected to the upper support 112 of the film-carriage frame 110. The first and second mounts 322 and 324are fixedly connected to the first and second spacers 216 and 218, respectively, of the rollersupport frame 210 of the roller support 200, such as via suitable fasteners. The roller-support guide 300 — and the roller support 200 connected to it — is pivotable about a pivot axis Asooa that is coaxial with the longitudinal axis of the first shaft 302. The roller support 200 is also pivotable (to the extent allowed by the first and second links 290a and 290b) about a pivot axis Aaoob that is coaxial with the longitudinal axis of the third shaft 306.

[0045] Figures 7A-7C, 8A-8C, 9A-9C, and 10A-10C show the roller support 200 moving from the closed position to the open position from different perspectives. Initially, the roller support 200 moves away from the film-carriage frame 110 in a substantially horizonal direction. During this movement, the second pivot axis A2oob moves horizontally away from and vertically toward (downward) the fist pivot axis A2ooa. After this initial substantially transverse movement, the roller support 200 pivots to the open position. During this movement, the second pivot axis A2oob moves further horizontally away from and further vertically toward (downward) the first pivot axis A2ooa. The initial substantially transverse movement — facilitated by the doubly pivotable first and second links 290a and 290b — enables the second-prestretch-roller gear 408g to unmesh from the first-prestretch-roller gear 406g without damaging the teeth of the gears.

[0046] As shown in Figure 4, when the roller support 200 is in the closed position, the film web FW extends from the roll R, passes between the first and second idler rollers 402 and 404, partially around the second idler roller 404, and contacts the first prestretch roller 406. The film web FW passes partially around the first prestretch roller 406, onto and partially around the second prestretch roller 408. The film web FW passes partially around the second prestretch roller 408, onto and partially around the third prestretch roller 410. The film web FW then passes partially around the third prestretch roller 410 and onto and partially around each of the third idler roller 412, the fourth idler roller 414, the fifth idler roller 416, and the sixth idler roller 418, before exiting the film carriage 100 and contacting the load L. The film web FW thus winds in a serpentine manner around rollers 402, 404, 406, 408, 410, 412, and 414 before contacting rollers 416 and 418, so: (1) a first surface of the film web FW contacts the first idler roller 402, the first prestretch roller 406, the third prestretch roller 410, the fourth idler roller 414, the fifth idler roller 416, and the sixth idler roller 416; and (2) a second surface of the film web FW opposite the first surface contacts the second idler roller 404, the second prestretch roller 408, and the third idler roller 412.

[0047] The ability of the roller support 200 to move to the open position enables easy removal and replacement of the film roll without threading the film web around the rollers. Figure 12A shows the rollers 400 with the roller support 200 in the closed position. Figure 12B shows the rollers 400 with the roller support 200 in the open position and with a film roll R mounted to the film carriage 100. Film F is pulled off the film roll R such at the film web FW extends between the rollers 402, 406, 410, and 414 mounted to the film-carriage frame 110 and the rollers 404, 408, and 412 mounted to the movable rollers support 200. Figure 12C shows the rollers 400 after the roller support 200 has moved back to the closed position. As the roller support 200 moves back to the closed position, the rollers 404, 408, and 412 engage the film web FW and force it into engagement with the rollers 402, 406, 410, and 414 and such that it follows the serpentine path described above.

[0048] The prestretch-drive assembly 430, best shown in Figures 5, is operably connected to the first, second, and third prestretch rollers 406, 408, and 410 and configured to drive the prestretch rollers so they stretch the film web FW as it travels between the prestretch rollers. The prestretch-drive assembly 430 includes a prestretch actuator 430a and a prestretch transmission including a first belt 431, a first gear pulley 432, a second gear pulley 434, a third gear pulley 436, and a second belt 438. The prestretch actuator 430a is an electric motor mounted to the film-carriage frame 110 (though it may be any other suitable actuator in other embodiments). The prestretch transmission operably connects the prestretch actuator 430a to the first and third prestretch rollers 406 and 410 (and, when the roller support 200 is in the closed position, to the second prestretch roller 408 via the first prestretch roller 406). The first and second gear pulleys 432 and 434 are fixed in rotation with the third prestretch roller 410. The third gear pulley 436 is fixed in rotation with the first prestretch roller 406. A gear pulley fixed in rotation with an output shaft of the prestretch actuator 430a is operably connected to the first gear pulley 432 via the first belt 431 such that rotation of the output shaft of the prestretch actuator 430a causes the first gear pulley 432 to rotate. This causes rotation of the second gear pulley 434 and the third prestretch roller 410 because they are fixed in rotation with the first gear pulley 432. The second gear pulley 434 is operably connected to the third gear pulley 436 via the second belt 438 such that rotation of the second gear pulley 434 causes the third gear pulley 436 to rotate. This causes rotation of the first prestretch roller 406 — and the first prestretch-roller gear 406g — fixed in rotation with the third gear pulley 436 to rotate. Since the first prestretch-roller gear 406g is meshed with the second prestretch-roller gear 408g, rotation of the first prestretch-roller gear 406g drives the second prestretch-roller gear 408g — and the second prestretch roller 408 — to rotate.

[0049] In this example embodiment, the sizes of the prestretch rollers, the prestretchroller gears, and certain components of the prestretch-drive assembly are selected such that the prestretch rollers are driven at different linear speeds to prestretch the film web FW. The linear speed at the outer surface of a given prestretch roller, which corresponds to the speed of film web when contacting the roller, is a function of the diameter and the rotational speed of the roller. For instance, two rollers having the same diameter and rotating at the same rotational speed (e.g., the same number of rotations per minute) will have the same linear speed. Two rollers with different diameters and rotating at the same rotational speed will have different linear speeds: the linear speed of the larger-diameter roller will be greater than the linear speed of the smaller-diameter roller.

[0050] The prestretch-drive assembly 430 is operably connected to the first, second, and third prestretch rollers 406, 408, and 410 and configured to drive them at first, second, and third linear speeds, respectively. The third linear speed is greater than the second linear speed, and the second linear speed is greater than the first linear speed. This results in the prestretchdrive assembly prestretching the film web FW in two stages: a first prestretch stage as the film web FW transitions from the first prestretch roller 406 to the second prestretch roller 408, and a second prestretch stage as the film web FW transitions from the second prestretch roller 408 to the third prestretch roller 410. The first, second, and third linear speeds of the first, second, and third prestretch rollers 406, 408, and 410 can be controlled such that 1-15 % of the stretching of the film web FW occurs in the first prestretch stage between the first and second prestretch rollers 406 and 408, and such that 85 — 99% of the stretching of the film web FW occurs in the second prestretch between the second and third prestretch rollers 408 and 410. The third linear speed is selected based on the desired film-feeding speed for the particular load being wrapped. To achieve this ratio of stretching, the first linear speed is generally set at 15-95% of the third linear speed, and the second linear speed is set at 101% — 150% of the first linear speed. Due to the fact that the third diameter of the third prestretch roller 410 is greater than the first and second diameters and of the first and second prestretch rollers 406 and 408, the third prestretch roller 410 may not have the greatest rotational speed even though it has the greatest linear speed.As a result, the amount of prestretch can range from 10% to 400%, which corresponds to the percentage amount of additional length added to the film web during the stretch. To explain using a non-limiting example, a 10% stretch corresponds to an increase in length from 10 feet to 11 feet (increasing the length by 10%), a 100% stretch corresponds to an increase in length from 10 feet to 20 feet (increasing the length by 100%), and a 400% stretch corresponds to an increase in length from 10 feet to 50 feet (increasing the length by 400%).

[0051] The cutting-and-sealing device (not shown) is supported by the wrappingmachine frame 10 and configured to, after the load L has been wrapped, cut the film web FW at a position between the load L and the wrapping assembly 40 to form a trailing end of the film web FW and to connect the trailing end of the film web FW to the wrapped load L to complete the wrapping process. Cutting the film web FW also creates a leading end of the film web FW. The cutting-and-sealing device is also configured to hold the leading end after cutting the film web FW and to connect the leading end of the film web FW to the next load as it is being wrapped. The cutting-and-sealing device can be any suitable conventional cutting-and-sealing device known in the art.

[0052] The operator interface 1000 is configured to receive inputs from an operator and, in certain embodiments, to output information to the operator. The operator interface includes one or more input devices configured to receive inputs from the operator. In various embodiments, the one or more input devices include one or more buttons (such as hard or soft keys), one or more switches, and / or a touch panel. In various embodiments, the operator interface 1000 includes a display device configured to display information to the operator, such as information about the palletized load, the status of the wrapping operation, or the parameters of the wrapping machine 1 (e.g., the rotational speeds of the prestretch rollers). The operator interface can include other output devices instead of or in addition to the display device, such as one or more speakers and / or one or more lights. In certain embodiments, the operator interface 1000 is formed as part of the wrapping machine 1 and is, for instance, mounted to the wrappingmachine frame 10. In other embodiments, the operator interface is remote from the wrapping machine 1.

[0053] The controller C includes a processing device communicatively connected to a memory device. The processing device can include any suitable processing device such as, but not limited to, a general-purpose processor, a special -purpose processor, a digital-signalprocessor, 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 can 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 wrapping machine 1 (such as to carry out a wrapping operation, as described below).

[0054] The controller C is communicatively and operably connected to the guide actuator 20a, the cutting-and-sealing device, the prestretch actuator 430a, and the wrappingassembly actuator 40a to control operation of these components in conjunction with the wrapping operation, as described below. The controller C is communicatively connected to the operator interface 1000 to: (1) receive signals from the operator interface 1000 that represent inputs received by the operator interface 1000; and (2) send signals to the operator interface 1000 to cause the operator interface 1000 to output (such as to display) information.

[0055] A wrapping operation in which the wrapping machine 1 is used to wrap the load L with the film F to secure the load L to the pallet P is now partially described. Initially, the circular guide 20 is at its upper position, and the cutting-and-sealing device holds the leading end of the film web FW. The controller C controls the conveyor C to move the load L on the pallet P through the infeed area 10a and into the wrapping area of the wrapping machine 1. After the load L on the pallet P reaches the wrapping area, the controller C controls the guide actuator 20a to lower the circular guide 20 such that the wrapping assembly 40 is at least partially vertically aligned with part of the load L. The controller C controls the cutting-and-sealing device to hold the leading end of the film web FW against or near the load L while controlling the wrappingassembly actuator 40a to rotate the wrapping assembly 40 relative to the circular guide 20 and the load L. The rotation of the wrapping assembly 40 relative to the load L combined with the cutting-and- fixing device holding the leading end of the film web FW against or near the load L causes the film web FW to be drawn off of the roll R, directed through the rollers of the film carriage 100, and wrapped around the load L.

[0056] Once the film web FW has been wrapped around the leading end, the controller C controls the cutting-and-sealing device to release the leading end and move away from the load L. The controller C continues to control the wrapping-assembly actuator 40a to rotate the wrapping assembly 40 while controlling the guide actuator 20a to vertically move the circular guide 20 such that the load L is wrapped with the film web FW in a spiral pattern. During wrapping, the controller C controls the prestretch actuator 430a to rotate the first, second, and third pre- stretch rollers 110, 120, and 130 such that they each have the appropriate linear speeds to prestretch the film web FW as it is drawn through the prestretch rollers 110, 120, and 130. After wrapping is complete, the controller C controls the cutting-and-sealing device to cut the film web FW from the roll R and secure the trailing end of the film web FW to the load L, thereby completing the wrapping operation. The controller C controls the conveyor C to move the wrapped load L and pallet P from the wrapping area and through the outfeed area 10b.

[0057] Figure 13 shows an alternative embodiment of the film carriage 100 including an automatic-opening-and-closing assembly. In this embodiment, the film carriage 100 includes an actuator 600, an arm 710, a connector 720, a first cam 730, and a second cam 740. The actuator 600 includes a piston 602 slidably received in a cylinder 604. The cylinder 604 is fixedly mounted to the film-carriage frame 110. One end of the arm 710 is pivotably connected to the piston 602. The other end of the arm 710 is fixedly connected to the first shaft 302 of the roller-support guide 300 such that the first shaft 302 and the arm 710 are fixed in rotation and pivotable about the pivot axis Asooa. The first cam 730 is fixedly connected to the third shaft 306 of the roller-support guide 300 such that the third shaft 306 and the first cam 730 are fixed in rotation about the axis Aaoob. The connector 720 is rigid and connects the arm 710 to a lobe of the first cam 730. The second cam 740 is fixedly connected to the third shaft 306 of the rollersupport guide 300 such that the third shaft 306 and the first cam 730 are fixed in rotation about the axis Asoob. The second cam 740 is positioned near a roller bearing (not labeled) of the lock actuator 230.

[0058] To open the movable roller assembly 200, the actuator 600 is operated to retract the piston 602 into the cylinder 604. The piston 602 carries the end of the arm 710 with it, which causes the arm 710 to pivot about the axis Aaooa and the connector 720 to move downward. This movement of the connector 720 causes the first cam 730 to rotate about the axis Aaoob. This causes the third shaft 306 and the second cam 740 to rotate with the first cam 730about the axis A oob. The second cam 740 is shaped such that as it forces the lock actuator 230 to pivot to its unlocked position, which causes the lock 240 to move to its unlocked position. As the arm 710 continues to pivot, it causes the first shaft 302 to rotate about the axis Asooa. Since the first and second arms 310 and 312 of the roller-support guide 300 are fixed in rotation with the first shaft 302, rotation of the first shaft 302 causes the entire roller-support guide 300 to pivot and carry the roller support 200 to its open position. Accordingly, the actuator is operably connected to the lock to move the lock from its locked position to its unlocked position while also being operably connected to the roller support to move the roller support from its closed position to its open position, and vice-versa. The controller C is operably connected to the actuator 600 and configured to control the actuator 600.

[0059] In other embodiments, the roller assembly is movable between the closed and open positions via any other suitable combination of movements. For instance, in certain embodiments, the roller assembly is translatable in at least one degree of freedom between the closed and open positions without the need to pivot.

Claims

Claims1. A film carriage for a wrapping machine, the film carriage comprising: a film-carriage frame; a first prestretch roller rotatably mounted to the film-carriage frame; a third prestretch roller rotatably mounted to the film-carriage frame, wherein a first space is defined between the first and third prestretch rollers; and a roller support comprising a roller-support frame and a second prestretch roller rotatably mounted to the roller-support frame, wherein the roller support is movable relative to the film-carriage frame between a closed position in which the second prestretch roller at least partially occupies the first space and an open position in which the second prestretch roller is removed from the first space.

2. The film carriage of claim 1, further comprising a prestretch-drive assembly operably connected to the first and third prestretch rollers and configured to rotate the first and third prestretch rollers.

3. The film carriage of claim 2, wherein when the roller support is in the closed position, the first prestretch roller is operably connected to and configured to rotate the second prestretch roller, wherein when the roller support is in the open position, the first prestretch roller is not operably connected to the second prestretch roller.

4. The film carriage of claim 3, further comprising: a first-prestretch-roller gear fixed in rotation with the first prestretch roller; and a second-prestretch-roller gear fixed in rotation with the second prestretch roller, wherein when the roller support is in the closed position, the first-prestretch-roller gear meshes with and drivingly engages the second-prestretch-roller gear, wherein when the roller support is in the open position, the first prestretch-roller gear is unmeshed from the second-prestretch-roller gear.

5. The film carriage of claim 4, wherein the prestretch-drive assembly is configured to rotate the first prestretch roller at a first linear speed, the second prestretch roller at a secondlinear speed, and the third prestretch roller at a third linear speed, wherein the third linear speed is greater than the first and second linear speeds of the second prestretch roller.

6. The film carriage of claim 5, wherein the second linear speed is greater than the first linear speed.

7. The film carriage of claim 6, wherein a diameter of the third prestretch roller is greater than a diameter of the first prestretch roller and greater than a diameter of the second prestretch roller.

8. The film carriage of claim 2, wherein the prestretch-drive assembly comprises a prestretch-drive actuator and a prestretch transmission operably connecting the prestretch-drive actuator to the first and third prestretch rollers.

9. The film carriage of claim 1, wherein the roller support is movable relative to the film-carriage frame in at least two degrees of freedom.

10. The film carriage of claim 9, wherein the roller support is pivotable relative to the film-carriage frame about first pivot axis.

11. The film carriage of claim 10, wherein the first pivot axis is fixed relative to the film-carriage frame and the second pivot axis is movable relative to the film-carriage frame.

12. The film carriage of claim 11, wherein the second pivot axis is pivotable about the first pivot axis relative to the film-carriage frame.

13. The film carriage of claim 12, wherein the roller support is pivotably connected to the film-carriage frame via a first link and a second link, wherein the first and second links are pivotable about the first and second pivot axes.

14. The film carriage of claim 13, wherein the second pivot axis moves downward and horizontally away from the first pivot axis as the roller support moves from the closed position to the open position.

15. The film carriage of claim 11, further comprising a roller-support guide pivotably mounted to the film-carriage frame and connected to the roller support, wherein the rollersupport guide is pivotable relative to the film-carriage frame about a third pivot axis different from the first and second pivot axes.

16. The film carriage of claim 15, further comprising an automatic opening-and- closing assembly operably connected to the roller-support guide and configured to pivot the roller-support guide to cause the roller support to move from the closed position to the open position.

17. The film carriage of claim 16, wherein the automatic opening-and-closing assembly comprises an arm fixedly connected to the roller-support guide and an actuator operably connected to the arm and configured to pivot the arm about the third pivot axis to pivot the roller-support guide.

18. The film carriage of claim 1, further comprising: a first idler roller rotatably mounted to the film-carriage frame, wherein a second space is defined between the first idler roller and the first prestretch roller; a second idler roller rotatably mounted to the roller-support frame, wherein a third space is defined between the second idler roller and the second prestretch roller; a third idler roller rotatably mounted to the roller-support frame, wherein a fourth space is defined between the second prestretch roller and the third idler roller; and a fourth idler roller rotatably mounted to the film-carriage frame, wherein a fifth space is defined between the third prestretch roller and the fourth idler roller, wherein when the roller support is in the closed position, the second idler roller at least partially occupies the second space and the third idler roller, the first prestretch roller at least partially occupies the third space, the third prestretch roller at least partially occupies the fourth space, and the third idler roller at least partially occupies the fifth space,wherein when the roller support is in the open position, the second idler roller is removed from the second space and the third idler roller, the first prestretch roller is removed from the third space, the third prestretch roller is removed from the fourth space, and the third idler roller is removed from the fifth space.

19. The film carriage of claim 18, wherein the roller support is movable relative to the film-carriage frame in two degrees of freedom.

20. The film carriage of claim 1, further comprising: a lock movable between a locked position and an unlocked position; and a lock actuator operably connected to the lock and configured to move the lock from the locked position to the unlocked position, wherein when the roller support is in the closed position and the lock is in the locked position, the lock prevents the roller support from moving to the open position, wherein when the roller support is in the closed position and the lock is in the unlocked position, the lock does not prevent the roller support from moving to the open position.

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