ZA200508271B - Wrapping method and device - Google Patents

Description

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FIELD OF THE INVENTION

THIS INVENTION relates to the wrapping of objects such as palletised loads with sheet material from rolls. In particular, the invention relates to a method and a device for wrapping an object, by hand. | BACKGROUND TO THE INVENTION

Techniques are known to wrap palletised loads such as boxes stacked on pallets, to secure the loads, to limit environmental exposure of the loads, etc.

The loads are typically wrapped with thermoplastic film from rolls, which is applied by hand by unrolling the film, while moving a roll around the pallet and the load, or is applied in an automated manner in a machine.

Known techniques used in automated machines for wrapping thermoplastic films around palletised loads include pre-stretching of the plastic film before wrapping it around the load and deformation of edges of the film to increase the mechanical strength of its edges. In automated wrapping, the tension under which the film is wrapped around the load can be controlled and all parts of the load can be wrapped with consistent tension.

In many applications, the substantial cost of automated wrapping machines of this type are not justified and palletised loads are wrapped by hand, by moving rolls of plastic film around the load and unwinding the film from the roll, to wrap the load. Tension can be applied to the rolls by applying braking friction to the loads, by hand, to place the films under tension when applying them, but this tension can obviously no be controlled. Further, it is often difficult for an operator who is wrapping a palletised load by hand, to reach all parts of the load and/or to handle the roll comfortably while wrapping all parts of the load. The result is that the plastic films with which palletised loads have been wrapped by hand, are generally not evenly distributed around the load and are prone to variations in the tension with which it has been wrapped. This adversely affects the mechanical strength and effectiveness of the wrapping to secure the load. These manual wrapping techniques do not allow for deformation of the edges of the plastic films prior to wrapping.

Operators can use simple mechanical devices to assist them in handling the rolls from which plastic films are unwound during mechanical wrapping of palletised loads. These devices include wooden rods and dispensers which hold the rolls on shafts, with one or more handles attached to the shafts. These devices assist in the ergonomics of handling the rolls, but still do no assist operators to control the tension with which the plastic films are applied and still do not provide for deformation of the edges of the plastic films. Some of the devices have handles that are positioned generally midway along the rolls, in cantilever fashion. These devices are prone to mechanical failure, especially if an operator pulls hard on the film while wrapping and while holding it by such a cantilevered handle.

It is an object of the present invention to assist in controlling the tension under which plastic films are wound around objects such as palletised loads, by hand.

It is a further object of the invention to assist in deforming the edges plastic films while winding the films around objects, by hand.

BRIEF DESCRIPTION OF THE INVENTION

According to a first aspect of the present invention there is provided a dispenser for dispensing film from a roll, said dispenser comprising: a frame, two shoulder elements, each defining a spigot, said shoulder elements being attached to the frame in a spaced configuration with their spigots facing each other, such that the respective ends of the roll are receivable on the spigots to rotate about an axis extending between the spigots; and means for urging at least one of the shoulder formations towards the other.

The first shoulder formation may be attached to the frame and the second shoulder formation may be displacable relative to the frame. Further, the urging means may include an adjustment mechanism configured to displace the second shoulder formation towards the first shoulder formation, such as an adjustment mechanism including a threaded element that can be displaced towards the first shoulder element, by twisting it.

A part of the frame may extend alongside the axis in a spaced configuration and may include at least one protuberance, protruding from the frame, so that it will interfere with the film, as it is dispensed from the roll. Preferably, the dispenser may include two of said protuberances, with inner edges spaced apart by a distance that is shorter than the distance between the shoulders of the shoulder elements and at least one protuberance, but preferably both, may define a recess extending generally perpendicular to the axis, in which an edge of the film can be deformed, as it slides through the protuberances.

According to another aspect of the invention there is provided a method of dispensing film from a roll, said method comprising: holding the roll by two shoulder formations, with spigots of the shoulder formations extending into ends of the roll, the shoulder formations being supported by a frame; attaching an end of the film to an object; pulling the frame relative to the object to apply a tensile load to the film and to unwind it from the roll; and urging at least one of the shoulder formations against the roll, to cause friction between the shoulder formation and the roll.

At least one of the shoulder formations may be urged against the roll by twisting a treaded element, attached to the shoulder formation, relative to the frame.

The method may include passing at least one edge of the film across a protuberance, protruding from the frame, to deform an edge of the film, preferably by gathering it into folds.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of non- limiting example, to the accompanying drawings in which:

Figure 1 is a three dimensional view of a dispenser in accordance with the present invention, in use; and

Figure two is a detailed sectional view through part of the dispenser of Figure 1.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to the drawings, a dispenser in accordance with the invention is generally indicated by reference numeral 10 and includes a rectangular frame 12 which supports a first or stationary shoulder formation 14, a second or rotating shoulder formation 16 and two protuberances in the form of gathering guides 18. A roll 20 of plastic sheet or film 22 is held on the shoulder formations 14,16.

The frame 12 can be of any suitably strong material, but should preferably also be light in weight, to allow easy manipulation by hand. In a preferred embodiment of the invention, the frame 12 is welded from aluminium tubing.

Each of the shoulder formations 14,16 includes a disc 24 with a diameter that is wider than the roll 20, and a spigot 26. The spigots 26 face each other and protrude into a bore 28 of the roll 20. The stationary shoulder formation 14 is fixedly attached to the frame 12 by way of an internal bolt 30.

The rotating shoulder formation 16 is rotatably fitted onto a shaft 32, with a bearing 34. Part of the shaft 32 is externally threaded to form a threaded bar 36, which extends through the frame 12. A threaded bush 38 is fitted in the frame 12, through which the threaded bar 36 passes in thread fashion, so that the shaft 32, including the threaded bar, is axially displaced relative to the frame and bush, when the shaft is twisted. A knurled knob 40 is attached to the end of the threaded bar 36, remote from the rotating shoulder formation 16 and a locknut is provided on the bar, between the bush 38 and the knob. The Knob 40, shaft 32 and threaded bush 38, together comprise an adjustment mechanism, configured to displace the rotating shoulder formation 16 axially.

A common axis (not shown) extends through all the components mentioned thus far, except for the frame and the guides.

Each of the guides 18 is attached to a part of the frame 12 that is spaced from the axis, but runs alongside the roll 20 in a parallel configuration. Each of the guides 18 is generally semi circular in shape and defines a recess in the form of a rounded groove 44 along its circumference. The part of each groove 44 closest to the other guide 18 is generally perpendicular to the axis and defines an inner edge and the inner edges are spaced apart by a distance that is much shorter than the width of the film 22 when it comes off the roll.

In use, the dispenser 10 is loaded with a roll 20 by twisting the knob 40 to move the rotating shoulder formation 16 towards the frame 12, until the space between the spigots 26 is large enough to place a roll between the shoulder formations 14,16. The knob 40 is twisted in the opposite direction to move the rotating shoulder formation 16 towards the stationary shoulder formation 14, with the spigots 26 extending into the bore 28 of the roll. The roll 20 includes a hollow cylindrical inner core 46, typically of cardboard, around which the film 22 is wound.

The film 22 will be selected for its intended application, but is typically a polyethylene stretch film, the thickness of which can vary.

Depending on the extent to which the film 22 needs to be stretched when applied to wrap an object, the knob 40 is twisted to urge the rotating shoulder formation 16 towards the stationary shoulder formation, so that a compressive load is applied to the roll 20 by the discs 24. It is to be appreciated that the compression will cause the roll 20 and rotating shoulder formation 16 to rotate together relative to the shaft 32, frame 12, etc., with negligible friction, owing to the bearing 34.

However, the compression will cause friction and/or increased friction between the roll 20 and the disc 24 of the stationary shoulder formation 14, if the roll rotates relative to the frame 12. The adjustment mechanism is locked in position with the lock nut 42, which is twisted until it engages the frame 12, to prevent rotation of the threaded bar 36. If necessary, the compressive load between the shoulder

-0- formations 14,16 can be adjusted by releasing the lock nut 42, twisting the knob 40 and re-tightening the lock nut.

An end of the film 22 is taken by hand from the roll 20 and a sufficient length of the film is unwound from the roll, to allow it to be attached to an object to be wrapped with the film. If the object is a palletised load, the end of the film 22 is typically attached to the pallet first. Once the end of the film 22 is attached to the pallet, the operator of the dispenser 10 grips it by the frame 12 and pulls the dispenser relative to the pallet so that more of the film 22 is unwound from the roli and can be wound onto the pallet, by moving the dispenser around the pallet. The operator then continues to wrap the pallet and its load, by continually pulling the dispenser relative to the pallet and its load and moving it around the pallet and its load.

While the film 22 is unwound from the roll 20, the friction between the roll and the disc 24 of the stationary shoulder formation 14 resists the unwinding and requires that substantial tension is applied to the film 22, to unwind it form the roll.

This causes the amount of tension with which the film 22 is wrapped around the pallet and its load to be high and to remain relatively constant, irrespective of the rate or force of wrapping, the comfort with which the operator can reach different parts of the pallet and its load, etc. The tension in the film 22 causes it to stretch and to exert a compressive load on the pallet and its load, thus securing the pallet’s load in place and protecting it against the environment.

In a preferred embodiment of the invention, the edges of the film 22 are tucked between the guides 18, to slide along the grooves 44, while being dispensed. The spacing between the inner edges of the grooves 44 cause the edges of the film to be deformed by gathering it into folds. The gathered edges 46 are much stronger that the unfolded film 22 and thus provides a wrapping with superior mechanical properties.

The semi circular shape of the guides 18 allow them to be changed around, in the event that the inside walls of the grooves 44 become warn in the vicinities of the inner edges.

Claims (13)

3 2005/G627Y CLAIMS

1. A dispenser for dispensing film from a roll, said dispenser comprising: a frame; two shoulder elements, each defining a spigot, said shoulder elements being attached to the frame in a spaced configuration with their spigots facing each other, such that the respective ends of the roll are receivable on the spigots to rotate about an axis extending between the spigots; and means for urging at least one of the shoulder formations towards the other.

2. A dispenser as claimed in Claim 1, wherein the first shoulder formation is attached to the frame and the second shoulder formation is displacable relative to the frame.

3. A dispenser as claimed in Claim 2, wherein the urging means includes an adjustment mechanism configured to displace the second shoulder formation towards the first shoulder formation.

4. A dispenser as claimed in Claim 3, wherein the adjustment mechanism includes a threaded element that can be displaced towards the first shoulder element, by twisting it.

5. A dispenser as claimed in any one of the preceding claims, in which a part of the frame extends alongside the axis in a spaced configuration and includes at least one protuberance, protruding from the frame.

6. A dispenser as claimed in Claim 5, which includes two of said protuberances, with inner edges spaced apart by a distance that is shorter than the distance between the shoulders of the shoulder elements.

7. A dispenser as claimed in Claim 5 or Claim 6, wherein at least one protuberance defines a recess extending generally perpendicular to the axis.

8. A method of dispensing film from a roll, said method comprising: holding the roll by two shoulder formations, with spigots of the shoulder formations extending into ends of the roll, the shoulder formations being supported by a frame; attaching an end of the film to an object; pulling the frame relative to the object to apply a tensile load to the film and to unwind it from the roll; and urging at least one of the shoulder formations against the roll, to cause friction between the shoulder formation and the roll.

9. A method as claimed in Claim 8, wherein at least one of the shoulder formations is urged against the roll by twisting a treaded element, attached to the shoulder formation, relative to the frame.

10. A method as claimed in Claim 8 or Claim 9, which includes passing at least one edge of the film across a protuberance, protruding from the frame, to deform an edge of the film.

11. A method as claimed in Claim 10, wherein the edge of the film is deformed by gathering it in folds.

12 A dispenser for dispensing film from a roll, substantially as described herein with reference to the drawings

13. A method of dispensing film from a roll, substantially as described herein with reference to the drawings. ——————— Dated this 12" day of October 2005 oem Brian Bacon & Associates Inc. Applicant's Patent Attorneys