Easy thread carriage for stretch film wrapping system

A stretch film wrapping machine includes a wrap location and a film carriage that is movable during wrap operations. The film carriage includes a first driven roller, a second driven roller and a drive a drive arrangement for the driven rollers. The carriage includes a primary frame part and a secondary frame part. A film path runs between the primary frame part and the secondary frame part and passes between the driven rollers. The secondary frame part moves relative to the primary frame part between an open position for film threading and a closed position for operation. The second driven roller is mounted to the secondary frame part for movement therewith and has a driven gear that engages with a drive gear of the drive arrangement when the secondary frame part is in the closed position. In the open position the driven gear dis-engages from the drive gear.

TECHNICAL FIELD

The present application relates to a system for applying stretch wrap film to loads, such as palletized loads, and more particularly to a film support and feed carriage stretch wrap film applying machines.

BACKGROUND

Palletized loads are typically wrapped in plastic stretch film prior to shipping to stabilize the load on the pallet and prevent product shifting off of the pallet during transport. By way of example, automated systems are known in which the palletized load is placed on a load platform that sits alongside a stretch film roll support mechanism (e.g., a support spindle) associated with a movable carriage. To wrap the palletized load the platform and palletized load are rotated causing film to be drawn off of the film roll while the stretch film roll support mechanism is also moved vertically up and down along a mast to cover the full vertical height of the palletized load. In another machine type, the palletized load remains stationary while the film roll support mechanism (e.g., mounted on a mast that extends downward from a rotatable overhead arm) travels around the load to cause film to be drawn off the film roll, while the film roll support mechanism simultaneously moves vertically up and down along the mast.

Such automated machines are commonly used to wrap large numbers of loads over time, and therefore film roll replacement is a task that operators regularly handle. Film roll replacement typically involves removing an empty roll core from the support spindle, loading an new stretch film roll onto the spindle and then threading the leading end of the film of the new film roll through a film stretch and/or feed roller system of the carriage.

Accordingly, it would be desirable to provide a carriage that facilitates the film threading operation.

SUMMARY

In one aspect, a stretch film wrapping machine for wrapping film about palletized loads includes a wrap location for receiving palletized loads to be wrapped and a film carriage that is movable relative to the wrap location during wrap operations. The film carriage includes a film roll support mandrel, and a roller assembly including at least a first driven roller and a second driven roller over which film can pass for delivery to the wrap location. A drive arrangement for the first driven roller and the primary driven roller is located at an upper part of the carriage. The carriage includes a primary frame part and a secondary frame part, where a film path is defined between the primary frame part and the secondary frame part and passes between the first driven roller and the second driven roller. The secondary frame part is movable relative to the primary frame part between an open position to provide access to the film path for the purpose of threading film along the film path and a closed position for operation. The first driven roller is mounted to the primary frame part and the second driven roller is mounted to the secondary frame part for movement therewith. The drive arrangement includes a drive gear on the primary frame part that engages with a driven gear at an end of the second driven roller when the secondary frame part is in the closed position. When the secondary frame part is moved to the open position the driven gear of the second driven roller dis-engages from the drive gear and moves into a spaced apart condition relative to the drive gear.

In one implementation, the drive arrangement is configured to rotate the first driven roller and the second driven roller in opposite directions.

In one implementation, the first driven roller has an upright orientation, the second driven roller has an upright orientation and the secondary frame part is mounted to pivot away from the primary frame part.

In one implementation, the first driven roller has a substantially vertical orientation, the second driven roller has a substantially vertical orientation and the secondary frame part is mounted to pivot away from the primary frame part about a substantially horizontal pivot axis located toward a lower end of the carriage, the driven gear is located at an upper end of the second driven roller.

In one implementation, a housing covers the drive arrangement, the housing includes a downwardly extending housing portion having a upwardly extending slot formed therein, the slot aligned with the drive gear, wherein the driven gear of the second driven roller moves through the slot when the secondary frame part is moved between open and closed positions.

In one implementation, a gear cover is located at one side of the driven gear, the gear cover also moves through the slot when the secondary frame part is moved between open and closed positions, and when the secondary frame part is in the closed position the gear cover and the downwardly extending housing portion cooperate to limit access to the driven gear from external of the carriage.

In one implementation, the carriage is mounted for vertical movement along a mast during wrap operations.

In one implementation, the mast is either (i) movable about the wrap location during wrap operations or (ii) stationary and a load platform of the wrap location is rotated during wrap operations.

In one implementation, a control arrangement, including a control unit and at least one sensor, monitors whether the secondary frame part is in the open or closed position.

In another aspect, a stretch film wrapping machine for wrapping film about loads includes a wrap location for receiving loads to be wrapped and a film carriage that is movable during wrap operations. The film carriage includes a first driven roller, a second driven roller and a drive a drive arrangement for the first driven roller and the second driven roller. The carriage includes a primary frame part and a secondary frame part, where a film path is defined between the primary frame part and the secondary frame part and passes between the first driven roller and the second driven roller. The secondary frame part is movable relative to the primary frame part between an open position to provide access to the film path for the purpose of threading film along the film path and a closed position for operation. The second driven roller is mounted to the secondary frame part for movement therewith and has a driven gear that engages with a drive gear of the drive arrangement when the secondary frame part is in the closed position. When the secondary frame part is moved to the open position the driven gear of the second driven roller dis-engages from the drive gear.

In one implementation, the drive arrangement is configured to rotate the first driven roller and the second driven roller in opposite directions and is located at an upper end of the carriage.

In one implementation, the first driven roller has an upright orientation, the second driven roller has an upright orientation and the secondary frame part is mounted to pivot away from the primary frame part.

In one implementation, the first driven roller has a substantially vertical orientation, the second driven roller has a substantially vertical orientation and the secondary frame part is mounted to pivot away from the primary frame part about a substantially horizontal pivot axis located toward a lower end of the carriage.

In one implementation, a housing covers the drive arrangement, the housing includes a downwardly extending housing portion having a upwardly extending slot formed therein, the slot aligned with the part of the drive arrangement, wherein the driven gear of the second driven roller moves through the slot when the secondary frame part is moved between open and closed positions.

In one implementation, a gear cover is located toward an external side of the driven gear, the gear cover also moves through the slot when the secondary frame part is moved between open and closed positions, and when the secondary frame part is in the closed position the gear cover and the downwardly extending housing portion cooperate to limit access to the driven gear from external of the carriage.

In one implementation, the carriage is mounted for vertical movement along a mast during wrap operations.

In one implementation, the mast is either (i) movable about the wrap location during wrap operations or (ii) stationary and a load platform of the wrap location is rotated during wrap operations.

DETAILED DESCRIPTION

Referring toFIG. 1, one embodiment of a stretch film wrapping system10is shown, which includes a rotatable load platform12alongside a mast14having an associated film dispensing carriage16mounted to the mast14and movable up and down along the mast14for wrap operations. The film dispensing carriage16includes a pre-stretch roller assembly20that receives film from a film roll22mounted on a film roll support mandrel assembly. For wrap operations, a palletized load is placed on the load platform12and a free end of the film exiting the pre-stretch roller assembly20is attached to the palletized load. The load platform12is rotated, thereby rotating the palletized load, and causing film to be drawn from the film dispensing carriage16. At the same time, the film dispensing carriage16is moved vertically up and down along the mast14to cover the full vertical height of the palletized load. Variations of such machines include fully automatic systems, in which the machine cuts the film at the end of the rotating operation and presses the trailing end of the cut film against the wrapped load, and semi-automatic systems, in which an operator performs the film cut and pressing steps upon completion of the rotation operation. The system10includes an operator interface24(aka human machine interface, HMI) with associated controller.

As shown inFIG. 2, another embodiment of a stretch film wrapping system30includes an overhead gantry32with a rotatable arm33. A mast34extends downward from the end of the arm33and includes an associated film dispensing carriage36mounted to the mast34and movable up and down along the mast34for wrap operations. The film dispensing carriage36includes a pre-stretch roller assembly40that receives film from a film roll42mounted on a film roll support mandrel assembly. For wrap operations, a palletized load43is positioned under the gantry32and centered below the rotation axis of the overhead arm33. A free end of the film exiting the pre-stretch roller assembly40is attached to the palletized load43. Through rotation of the overhead arm33, the mast34is then rotated about the palletized load43while the palletized load43remains stationary, causing the film to be drawn from the film dispensing carriage36. At the same time, the film dispensing carriage36is moved vertically up and down along the mast34to cover the full vertical height of the palletized load43. Similar to the machine ofFIG. 1, variations of such overhead gantry type machines can include fully automatic systems and semi-automatic systems. The system30includes an operator interface44with associated controller to control the wrap operation.

Advantageously, the film dispensing system of either of the above machine types, as well as other existing stretch film wrapper machines, can incorporate a film thread feature that provides for simple film threading while at the same time providing an S-path through driven rollers of the pre-stretch roller assembly. One embodiment of this feature is described below with respect toFIGS. 3-13, but other embodiments are contemplated.

Referring toFIGS. 3-5, a film dispensing carriage36is shown and includes a film roll support mandrel50located to one side of a carriage housing52within which a set of rollers (not shown) are located. The set of rollers includes at least two driven rollers54and56(seen inFIGS. 6-8). A film roll is loaded onto the mandrel50and fed through the housing52and over the driven rollers for delivery to the wrap location of the machine on which the carriage36is installed. As shown, in addition to the driven rollers, the carriage36may include additional rollers58,60,62,64and66over which the film may travel as it passes along the film path defined by the carriage36. A drive arrangement70for the driven rollers is located at an upper part of the carriage housing52, and may include a primary mover, such as motor72, that drives a belt or chain74, which in turn engages a driven gear76at the top of the driven roller54. The belt or chain74also drives a drive wheel/plate78which in turn drives a belt or chain80that engages a drive wheel/plate82, where a drive gear84extends downward from drive wheel82.

The carriage36includes a primary frame part90(FIG. 6) and a secondary frame part92(FIGS. 7 and 8), where the film path94is defined between the two frame parts. Within the housing52the film path94passes between the driven rollers54and56. The secondary frame part92is movable relative to the primary frame part90between an open position to provide access to the film path94for the purpose of threading film along the film path94and a closed position for operation. The driven roller54and rollers58,60and62are mounted to the primary frame part90, while the driven roller56and rollers64and66are mounted to the secondary frame part92so that the rollers56,64and66all move with the secondary frame part92.

In operation, a film roll42is mounted on the mandrel50and the secondary frame part92is moved away from the primary frame part90to open the film path94as shown inFIG. 9. The film is then pulled through the film path94along the externally facing side of all of the rollers58,54,60and62. When the secondary frame part92is then moved back to the closed position, the drive roller56moves into contact with the roller58to form a nip therebetween, through which the film passes. Likewise, the roller66moves into contact with the drive roller54to form a nip therebetween, through which the film also passes. The result is an S-shaped film drive path94as suggested in the top schematic view ofFIG. 13. As suggested in the top view ofFIG. 13, in order to drive the film in the same direction, driven roller54and driven roller56must be rotated in opposite directions.

Thus, driven roller54is mounted to the primary frame part90and driven via gear76of the drive arrangement. Driven roller56is mounted to the secondary frame part92and is driven by a drive gear84on the primary frame part90that engages with a driven gear100at an upper end of the driven roller56when the secondary frame part92is in the closed position. On the other hand, when the secondary frame part92is moved to the open position the driven gear100of the driven roller56disengages from the drive gear84and moves into a spaced apart condition relative to the drive gear86as shown inFIG. 9.

It is generally contemplated that in most stretch film wrapping machine implementations, the various rollers of the carriage will all be oriented in upright orientations (i.e., orientations in which the longitudinal axis of the roller is nearer to vertical than it is to horizontal). By way of example, in the machine of the type shown inFIG. 2the rollers would typically be offset at least fifty degrees from horizontal. In the machine of the type shownFIG. 1, the rollers will typically have a substantially vertical orientation (i.e., wherein the longitudinal axis of the rollers is offset from vertical by no more ten degrees).

As best seen inFIGS. 5 and 9, a housing portion110covers the drive arrangement and includes a downwardly extending front portion having a upwardly extending slot112formed therein. The slot aligns with the drive gear84and the driven gear100of the driven roller56moves through the slot112when the secondary frame part92is moved between open and closed positions. In this regard, the secondary frame part92may be mounted for pivotal movement about a substantially horizontal114axis near the lower end of the carriage36. A gear cover116is located at one side of the driven gear100and also moves through the slot112when the secondary frame part92is moved between open and closed positions. When the secondary frame part92is in the closed position, the gear cover116and the downwardly extending housing portions alongside the gear cover cooperate to limit access to the driven gear from external of the carriage36. Alternately, the secondary frame part92may be mounted for linear movement toward and away from the primary frame part90for transition between the open and closed positions.

As suggested inFIG. 12, by incorporating the driver roller arrangement atop the carriage, the carriage36can be adequately moved downward to a position low enough to dispense film to the bottom of a palletized load.

It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation, and that changes and modifications are possible.