Stretch Film Dispenser For Orbital Pallet Wrappers

This application is a continuation of U.S. non-provisional patent application Ser. No. 17/246,994 filed on May 3, 2021 continuation of U.S. non-provisional patent application Ser. No. 16/037,721, filed on Jul. 17, 2018 of continuation of U.S. non-provisional patent application Ser. No. 13/919,132, filed on Jun. 17, 2013, which claim priority to U.S. Provisional Patent Application No. 61/661,112, filed on Jun. 18, 2012, the contents of which are incorporated herein by reference.

This invention relates generally to a wrapping apparatus and, more particularly, to an orbital stretch wrapping apparatus for packaging.

Wrapping stretch film around a cargo before shipment has been utilized for many years. The plastic film binds the products into a stable, more secured load that can be easily shipped from the manufacturing source of the products to the end user. Generally, the wrapped cargo is sized to be placed onto a pallet that facilitates the handling of the cargo during transportation and during the movement from one location to another.

Stretch film wrapping devices have traditionally been utilized to place stretch film around the cargo on the pallet. To this end, some stretch film wrapping machines place the cargo onto a rotating turntable while the roll of plastic stretch film, which is oriented vertically, is held in a stationary position for the application of the stretch film as the cargo is rotated on the turntable. One such apparatus can be found in U.S. Pat. No. 4,299,076, granted on Nov. 10, 1981, to John R. Humphrey, in which the cargo is placed onto a pallet and then moved along a horizontal roller conveyor to reach the turntable where the plastic film is applied as the pallet and the load thereon is rotated about a vertical axis. Another such wrapping apparatus is found in U.S. Pat. No. 5,606,849, granted to Roger V. Bettenhausen on Mar. 4, 1997. The vertically oriented roll of plastic stretch film is vertically movable to facilitate the application of the stretch film to the entire vertically oriented faces of the palletized cargo as the turntable is rotated.

Another more commonly found configuration of the stretch film wrapping system has the cargo placed on the pallet which is held in a stationary position while the wrapping apparatus rotates around the cargo to apply plastic stretch film to the vertically oriented faces of the palletized cargo. One example of such a wrapping machine can be found in U.S. Pat. No. 6,253,532, issued on Jul. 3, 2001, to Kenneth S. E. Orpen, in which the vertically oriented roll of plastic stretch film is carried on an arm that is rotated about a vertical axis of rotation carried by the apparatus and positioned over top of the cargo to be wrapped. In the Orpen wrapper apparatus, the cargo is anticipated to be in a cylindrical shape which is also rotated about a horizontal axis while the plastic stretch film is being applied to the cargo. The end result is that the entire cylindrical object is wrapped with the plastic stretch film. Such wrapping devices are commonly found in the agricultural industry to wrap cylindrical bales of hay or other organic material to create an airtight seal that converts the organic material into a silage product.

A variation of the stretch film wrapping machines having vertically oriented rolls of stretch film can be found in U.S. Pat. No. 7,581,368, granted to Darrel Bison on Sep. 1, 2009, and in U.S. Pat. No. 8,037,660, issued to Patrick R. Lancaster, III, et al, on Oct. 18, 2011. In these alternative wrapping machines, the plastic is applied as a rope that is passed around the vertically oriented faces of the cargo being secured and stabilized thereby. For some forms of cargo to be wrapped into a stabile shippable configuration, the consolidation of the stretch film into a rope configuration provides adequate stabilization of the cargo.

An orbital variation of the plastic stretch film wrapping system can be found in U.S. Pat. No. 4,723,393, issued on Feb. 9, 1988 to Peter Silbernagel, wherein the plastic stretch film is applied around the cargo from a generally horizontally oriented roll of stretch film that is passed vertically around the cargo to be stabilized for shipment. In the '393 patent, the cargo being wrapped in plastic is wrapped while being passed through the center of the wrapping mechanism, the wrapped cargo being subsequently shipped with or without the use of a pallet. The orbital wrapping mechanism is operated within a gap formed in a horizontal conveyor along which the cargo is passed to be wrapped in stretch film.

The orbital stretch wrapping apparatus shown in U.S. Pat. No. 6,564,532, issued to Robert J. Gutche on May 20, 2003, has the horizontally oriented roll of stretch film mounted on an arm that is rotated about the cargo and pallet being wrapped in plastic. The wrapping mechanism in the '532 patent is configured substantially like the vertical axis wrappers as depicted in U.S. Pat. No. 6,253,532, except oriented with the axis of rotation of the arm carrying the roll of plastic stretch film being positioned horizontally. A significant difference between the orbital stretch wrapping apparatus shown in U.S. Pat. No. 4,723,393 and the wrapping mechanism shown in U.S. Pat. No. 6,564,532 is that the apparatus in U.S. Pat. No. 6,564,532 wraps stretch film around both the cargo and the pallet on which the cargo is situated.

A commercially available stretch film wrapping system of the orbital configuration is marketed under the brand of “Yellow Jacket”. This “Yellow Jacket” orbital wrapping mechanism has a base frame supporting a cylindrical wrapping mechanism that is linearly movable along the base frame. Within the cylindrical wrapping mechanism is an orbital wrapper that carries a roll of plastic stretch film positioned horizontally. The plastic roll is then driven around the cylindrical wrapping mechanism to dispense plastic stretch film around the cargo and the pallet on which the cargo is mounted. Typically, the pallet bearing the cargo is carried by a forklift in a manner that the cargo bearing pallet is positioned in the center of the cylindrical wrapping mechanism. The orbital drive is actuated to spin the roll of plastic stretch film around cargo and pallet and apply the stretch film thereto. The cylindrical wrapping mechanism is then moved along the base frame so that the plastic stretch film is applied along the entire longitudinal length of the cargo and pallet. The end result is that the cargo is secured directly to the pallet to provide stability and security to the wrapped cargo.

One of the difficulties in applying plastic stretch film around the cargo, whether or not the pallet is wrapped in plastic stretch film with the cargo, is that the stretch film is not placed in tension as the stretch film is being applied to the cargo. Although an adequate number of layers of the plastic film will ultimately resolve the stability problem inherent with a loose application of the stretch film to the cargo, more plastic stretch film is applied than is necessary to provide proper stability and security to the wrapped cargo.

Thus, it would be desirable to provide a plastic stretch wrap dispensing mechanism that would place tension on the stretch film as the plastic stretch film is being applied to the cargo. The end result is that less plastic stretch film would be required to stabilize a cargo being wrapped and less time would be needed to apply the stretch film to wrap and stabilize a cargo for shipment.

It would also be desirable to provide an orbital stretch film wrapping machine that is less expensive to manufacture while providing the end results of a wrapped, stabilized cargo bearing pallet.

It is an object of this invention to overcome the disadvantages of the known prior art by providing an orbital stretch film wrapping system. An orbital stretch wrapping apparatus is provided and includes a base frame, a circular ring mounted on the base frame and rotatable with respect to the base frame about an axis of rotation, a stretch film dispenser mounted on the circular ring and rotatable with the circular ring about the axis of rotation, the stretch film dispenser having a subframe fixed to the circular ring, a roll of stretch film mounted to the subframe, a first feed roller mounted to the subframe, a second feed roller mounted to the subframe, and a brake member connected to the first feed roller and the second feed roller. The stretch film dispenser, the first feed roller, and the second feed roller are rotatable with respect to the subframe.

Referring first to, a stretch film wrapping system incorporating the principles of the instant invention can best be seen. The orbital stretch wrapping apparatusis formed with a base frameoperable to support the wrapper apparatuson a floor surface. The base framesupports a circular ringthat is rotationally mounted on the base frame. A plurality of rotational supports, preferably in the form of rubber tires, are mounted on the base frameto rotatably support the circular ring. Preferably, one rotational supportis located at each corner of the base framemounted on a gusset spanning across the corner of the base frame. Three of the rubber tiresare idlers that simply support the rotational movement of the circular ring. The fourth rubber tireis rotatably driven by an electrical motorto power the rotation of the circular ring.

A stretch film dispenseris mounted in a cantilevered manner on the circular ringso as to not interfere with the rotational support of the circular ringby the rubber tires,. A counterweightis also mounted on the circular ringdiametrically opposite the mounting of the stretch film dispenserso that the rotation of the circular ringwith the stretch film dispensermounted thereon can be balanced. Alternatively, a second stretch film dispenser could be supported on the circular ringin diametric opposition to the first stretch film dispenserinstead of the counterweight.

The circular ringcarrying the stretch film dispenseris powered to rotate relative to the base frame. The circular ringdoes not move longitudinally relative to the base frame; therefore, the stretch film supplied by the stretch film dispenser, as will be described in greater detail below, will only be applied in a single swath to the cargo inserted into the wrapping apparatus. Thus, the construction of the wrapping apparatusis substantially simplified without providing a track on the base framethat would support a longitudinal movement of the circular ringin order to apply the stretch film to the cargo in longitudinally spaced swaths or in a spiral manner. The application of stretch film to the cargo to be wrapped can be accomplished by moving the cargo relative to the circular ring, as will be described in greater detail below.

The stretch film dispenseris best seen in. The dispenserincludes a subframesecured to the circular ringin an offset or cantilevered orientation. The subframecan be stabilized by a pair of optional stabilizing rodsthat are attached to the remote end of the subframeand then to the circular ring on opposite sides of the subframein a manner that will not interfere with the support of the exterior surface of the circular ringon the rubber tires,. The subframerotatably supports the roll of stretch film, such as by a shaftthat extends through the core of the roll of stretch filmor through the application of end capsas described in greater detail below. The subframealso rotatably supports first and second feed rollers,in proximity to the roll of stretch filmto receive the stretch film from the roll. Preferably, the feed rollers,have the same diameter and are formed of a relatively soft rubber or neoprene.

Referring now to the first embodiment of the stretch film dispensershown in, each of the two feed rollers,have at one end thereof a gear,. The two gears,are meshed with one another within a casingto control the differential speed of the associated rollers,. The first feed roller, which is the feed roller that is physically closest to the roll of stretch film, has a larger gearthan the gearat the end of the second feed roller, as is best seen in. The relative sizes of the two gears,are such that the first feed rollerrotates approximately 45% slower than the second feed roller. The end result is that the stretch film wrapped from the supply rollaround the first rollerand then back wrapped around the second roller, as is reflected by the arrows in, has a tension induced thereon during the application of the stretch film to the cargo placed at the center of the rotatable circular ring.

One skilled in the art will recognize that the two feed rollers,are not powered in rotation. The rotation of the feed rollers,is caused by the wrapping of the stretch film around the cargo as the circular ringrotates spinning the dispenseraround the cargo to apply the stretch film thereto. The pulling of the stretch film against the second rolleras the dispenseris rotated with the circular ringaround the cargo causes the second rollerto rotate. The intermeshed gears,, transfer the rotational movement of the second rollerto the first roller. The relative differential speeds of rotation of the first and second rollers,induce tension into the stretch film as the stretch film is unrolled from the supply roll.

As best seen in, the rollof stretch film is preferably mounted on a pair of end capspositioned at each opposing end of the roll, although only one of the end capsis depicted in. Each end capis mounted on a stub axlethat is supported in a mounting flangeforming part of the subframe. A pinengaged in at least one of the stub axlesretains the stub axlesand associated end capsin position on the subframeto dispense a supply of stretch film from the rollaround the feed rollers,to the cargo being wrapped. The end capsare simply plugged into the opposing ends of the carrier tube (not shown) on which the stretch film is wrapped and retained there by friction and an inability to move laterally due to receipt of the stub axlesinto the mounting flanges.

Referring now to, a second embodiment of the stretch film dispensercan be seen. The primary difference between the first embodiment of the stretch film dispenserdepicted inand the second embodiment of the stretch film dispenserinis the manner in which the first feed rollis driven from the second feed roll. In the second embodiment shown in, the corresponding ends of the feed rolls,have mounted thereon sprockets,, instead of intermeshed gears,. The sprockets,are entrained by an endless chainthat transfers rotational motion from the second feed rollto the first feed roll. The chainrequires a tensioning idler, which can be in the form of a positionable curved blockas depicted in, or as a separate idler sprocketrotatably mounted on the subframe, to engage the chainand maintain tension therein.

Referring now to the third embodiment of the stretch film dispensershown in, a brake memberis added to the dispenserto further restrict the movement of the stretch film from the rollof stretch film around the two feed rolls,and onto the cargo to be wrapped. The brake membercarries a sprocketthat is entrained by the chainalong with the sprockets,on the two feed rolls,and the tensioning idlerso that the movement of the chainaround the sprockets,,and, is restricted by the brake memberwhich applies a drag on the chain. The use of the brake membercan allow the sprockets,on the feed rolls,to be the same size, as differential speed of the respective rollers,is no longer needed as the brake memberwill provide the necessary tension in the stretch wrap as the dispenseris rotated about the circular ring. Preferably, the brake memberwill be operatively adjustable in a known manner to vary the resistance imparted by the brake memberin the application of the stretch film to the cargo.

A manually adjustable brake memberis depicted in. The gearis modified to include a rotor portionagainst which a braking discpresses into engagement to restrict the rotation of the gear. The braking discis biased against the rotor portionby s compression springthat is contained by a spring housing memberreceived on a pair of guide pinssupported on the braking disc. The spring housingis movable along the guide pinsto selectively vary the compression on the spring, and thus the spring force exerted by the springonto the braking disc. The position of the spring housingis controlled by the adjustment rodthat has a head portioncapturing an actuation armon the spring housing. The adjustment rodis treaded into a mountsupported on the subframeto allow the adjustment rodto move relative to the mount

In operation, the amount of tension placed on the stretch film as the stretch film is being wrapped around the cargo is a function of the amount of spring force exerted by the springonto the braking discto engages the face of the rotor portion. The compression of the springis controlled by moving the adjustment rodinto or outwardly of the mount, as this movement controls the positioning of the spring housingalong the guide pins. A selective movement of the adjustment rodcan be accomplished by utilizing an Allen wrench (not shown) or socket wrench (not shown) to engage the headand cause rotation thereof.

In, a variation of the manually adjustable braking devicecan be seen. In lieu of an adjustment rodthreaded into a mount, the position of the spring housingalong the guide pinscan be controlled by a linear actuatorsecured to the subframeand connected to the actuation armfor extension and retraction that moves the spring housingalong the guide pins. The linear actuatoris preferably electrically operated, and may be battery powered, to permit a remote control of the movement of the linear actuator, and the amount of tension asserted on the stretch film as the stretch film is applied to the cargo being wrapped. A remote controller (not shown) can vary the tension in the stretch wrap as the stretch wrap is being applied by increasing the spring force exerted by the springas a function of the number of revolutions of the stretch film dispenseraround the cargo being wrapped. As a result, the initial wraps of the stretch film can be applied to the cargo under low torque and then increase with each revolution or each increment of revolutions of the dispenseraround the cargo.

In operation, the pallet (not shown) having a cargo (not shown) supported thereon is lifted by a fork lift (not shown) with the tines inserted into the pallet in a conventional manner. The fork lift operator inserts the cargo bearing pallet into the center of the circular ring. The loose end of the stretch film is secured on the cargo and the electric motoris started to drive the rotation of the drive wheel. The drive wheelrotates the circular ringand rotates the stretch film dispenseraround the pallet and the cargo mounted thereon. As the stretch film dispenseris rotated around the pallet and cargo, the fork lift operator advances the fork lift, and the pallet supported thereon further into the circular ring, thus advancing the cargo and pallet longitudinally relative to the longitudinally fixed circular ringand the base frame.

The differentially rotated feed rollers,of the stretch film dispenserkeep the stretch film taut as the stretch film is wrapped around the cargo and pallet. As a result, the cargo and pallet require less stretch film to stabilize the cargo on the pallet and the wrapping of the cargo and pallet. Accordingly, the process of wrapping a cargo and pallet for shipment will take less time to accomplish. Furthermore, since the base frameof the wrapping apparatusdoes not have a track to enable the longitudinal movement of the circular ring relative to the cargo, the wrapping apparatus can be manufactured less expensively. When the cargo and pallet have been wrapped adequately with the stretch film to stabilize the cargo on the pallet, the stretch film is severed and the fork lift operator withdraws the wrapped pallet and cargo for subsequent shipping. One skilled in the art will note that the stretch film is wrapped in an orbital manner around both the pallet and the cargo, thus securing the cargo to the pallet and providing a highly stabilized package for shipment. In the third embodiment of the stretch film dispenser, as described above, the brake memberwill maintain tension in the stretch film as the stretch film is being wrapped around the cargo to be shipped.

It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the invention.