GB2109772A - Device for wrapping loads with stretchable wrapping material - Google Patents

Abstract

In a hand-held device for wrapping a load with a web 28 of stretchable plastics film, a deflector strip 30 of rigid plastics material is attached to an upright 4 of the frame 1 of the device so that it is disposed in spaced relation with the roll 26 of the web and substantially parallel to the axis thereof. The deflector strip has a substantially straight edge 33 adjacent the roll and convexly curved surface 32 contiguous with the straight edge and extending away from the roll. When the web 28 is dispensed from the roll 26 it may be engaged against the straight edge 33 of the deflector and against at least part of the adjoining curved surface, the extent of the curved surface which is engaged being controlled by manipulating the entire device so as to alter the angle between the load, the deflector strip and the roll. This enables the degree of stretch applied to the web during a wrapping operation to be easily and rapidly changed and reduces the tendency of the web to "neck-in". <IMAGE>

Description

SPECIFICATION Improvements in devices for wrapping loads with stretchable wrapping material The present invention relates to devices for wrapping loads with webs of stretchable wrapping material which is pulled, under tension, from a roll of the web mounted in the device.

Such devices may be used for circularly or spirally wrapping even or uneven loads, such as a single article or a stack of goods on a pallet, with a web of stretchable plastics film, paper or other stretchable wrapping material in order to bind the load in place, protect the load during transportation and storage, and/or guard against pilferage.

During a stretch wrapping operation, the web of wrapping material is stretched to a considerable extent in order to bind the load securely. For example, a web of plastics wrapping film may be stretched by 5060%. Such a degree of stretching causes the width of the film to be significantly reduced as it is pulled from the roll. This reduction is commonly referred to as "necking in". It results in the use of more wrapping film than would otherwise be necessary in wrapping operations.

Moreover, with hand held wrapping devices, it is frequently necessary to adjust the drag or tension applied to the web of wrapping material during a wrapping operation by adjusting the clamping or braking force applied to the core of the roll of wrapping material. For example, the clamping force may be initially set to a low value to facilitate attachment of the web to a load, upon commencement of a wrapping operation, and thereafter, the clamping force is increased to produce the required amount of drag and, hence, stretch in the wrapping web during the main part of the winding procedure.

It is an object of the present invention to reduce necking-in of a web of stretchable wrapping material as it is dispensed, under tension, from a wrapping device, and to permit the degree of stretch applied to a web, during a wrapping operation, to be easily and rapidly changed.

The present invention consists in a device for wrapping a load with a web of stretchable wrapping material dispensed from a roll of the material mounted in the device, in which a deflector member is disposed in spaced relation with a roll substantially parallel to the axis thereof, said deflector member comprising a substantially straight edge adjacent the roll and a convexly curved surface contiguous with the straight edge and extending away from the roll, whereby the web dispensed from the roll may be engaged against the straight edge of the deflector and progressively against its curved surface by moving the deflector member so as to deflect the path of travel of the web pulled from the roll.

The deflector member may be made from a strip of rigid plastics material, such as a rigid P.V.C. moulding, which is attached to a rod or bar fixed to or forming part of the roll holder.

Surprisingly, when the web is pulled, under tension, from the roll in contact with the deflector, the latter minimises the tendency of the web to neck-in and stretching is achieved at the expense of the thickness of the web rather than its width.

By retaining the width of the web nearly the same as that of the unstretched web, the invention enables as much as 20% saving to be achieved in the use of wrapping material for wrapping loads.

Moreover, as the web is pulled from the roll in contact with the deflector member, the latter applies drag to the web and the degree of drag and hence stretch applied to the web can readily be adjusted by altering the width of the zone of the surface contact of the deflector member with the web. For example, with a hand wrapping device embodying the invention, the clamping force applied by the core supports engaged with the roll core may be adjusted to apply a low initial drag to the web and, thereafter, the drag and the degree of stretch of the web may be readily varied by the operator, as the web is dispensed, by simple manipulating the device so that the deflector member deflects the web to a greater or lesser extent, from a straight path of travel from the roll to the load, thereby altering the width of the zone of contact of the web with the deflector member.

In order that the invention may be more readily under stood, reference will now be made to the accompanying drawings in which: Fig. 1 is an elevational view, partially in section, of a hand wrapping device constructed according to the invention, and Fig. 2 is a section on the line Il-Il of Fig. 1.

The hand wrapping device is illustrated in the drawings is fully described in our prior specification No. 2069457A and will only be described herein in so far as is necessary for the understanding of the present invention.

Referring to the drawings, the wrapping device comprises a frame 1 which is of rectangular configuration in elevation and comprises a base 2, two mutually parallel uprights 3, 4 projecting upwardly from the base, and a hinged cross bar 5.

The uprights and bar are hollow square section members and the base 2 is an open framework structure of generally rectangular shape in plan on which the frame 1 can be stood in an upright position when not in use. The cross frame member 5 is hinged to the upper end of the upright 3 by a clevis 7 and, at its opposite end, the bar is releasably secured to the upper end of the upright 4 by a screw fastening device 10.

Hinged to the centres of the base 2 and the bar 5 are two core supports 1 7.

In order to load a roll 26 of stretchable wrapping material into the device, which may conveniently be effected with the device standing on its base 2, the screw fastener 10 is released and the bar 5 is swung into its open position. A roll 26 is then located in an upright position in the frame with the bottom end of its core 27 engaged with the bottom core support 17. The bar is then shut to engage the upper core support with the upper end of the core, whereupon the screw fastener is engaged and its knob 14 is screwed down onto the bar 5 in order to lock the bar in its shut position. The knob may be further tightened to increase the clamping force exerted on the core by the core supports 17 and, hence, the drag applied to the web 28 pulled from the roll 26.

Fastened along one side of the upright 4, at or adjacent its outer edge, is a deflector strip 30.

This deflector strip is extruded from rigid plastics material and is adhered to the face of the upright by suitable adhesive. The bar mounts the deflector strip in spaced relation with the roll 26 and substantially parallel to its axis. The deflector strip extends along the bar for at least the width of the web 28 to be dispensed from the device and has the cross sectional shape illustrated in Fig. 2. It comprises a rebate 31 extending along its edge adjacent the roll and this rebate is connected to the opposite edge of the strip by a convexly curved surface 32. The rebate forms a substantially straight edge 33 adjacent the roll which may be engaged with the web 28 dispensed from the roll, and this straight edge is contiguous with the convexly curved surface 32 which extends away from the roll.

When the device is to be used to wrap a load, such as a stack of goods on a pallet, the web 28 is led over the deflector strip 30, as illustrated in Fig.

2, and its leading edge is fixed to the top or bottom of the load. To facilitate pulling of the web from the roll for this operation, the fastener 10 is only tightened sufficiently to retain the roll securely mounted in the device and not to apply any significant degree of drag to the web. Having attached the web to the load, the operator grips the device by the upright 3 and walks around the load so as to allow the web to be pulled from the roll and produce a spiral wrap of overlapping turns about the load. In order to achieve the desired amount of stretch in the wrapped turns, a suitable braking force must be applied to the web as it is pulled from the roll. This determines the tensile force required to pull the web from the roll and, hence, the degree of stretch applied to the web.A suitable braking force is applied to the web by engaging the deflector strip 30 with the web and deflecting it from the direct path of travel between the roll and the load. The web firstly engages the sharp edge 33 of the deflector strip which applies an initial drag, and, thereafter, the degree of drag can be progressively increased by turning the device so as to engage more of the deflector curved surface 32 with the web. The deflector strip also prevents the web from necking-in to any significant extent. The action of the deflector strip is assisted by the web also engaging the inner edge of the upright 4, as illustrated in Fig. 2. If required, the fastener 10 may be used for making fine adjustments to the drag appliej to the web and, once these have been made, no further adjustment of the fastener may be required during the life of the roll 26.The degree of stretch may be simply and rapidly adjusted by the operator manipulating the holder to change the width of the zone of contact of the deflector strip with the web.

Whilst a particular embodiment has been described it will be understood that modifications can be made without departing from the scope of the invention.

Claims (Filed on 23 Nov 82) 1 A device for wrapping a load with a web of stretchable wrapping material dispensed from a roll of the material mounted in the device, in which a deflector member is disposed in spaced relation with the roll substantially parallel to the axis thereof, and is constructed and arranged so that the web dispensed from the roll may be engaged progressively against the deflector surface by moving the deflector member so as to deflect the path of travel of the web pulled from the roll.

2. A device for wrapping a load with a web of stretchable wrapping material constructed and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (2)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   engage the upper core support with the upper end of the core, whereupon the screw fastener is engaged and its knob 14 is screwed down onto the bar 5 in order to lock the bar in its shut position. The knob may be further tightened to increase the clamping force exerted on the core by the core supports 17 and, hence, the drag applied to the web 28 pulled from the roll 26.

   Fastened along one side of the upright 4, at or adjacent its outer edge, is a deflector strip 30.

   This deflector strip is extruded from rigid plastics material and is adhered to the face of the upright by suitable adhesive. The bar mounts the deflector strip in spaced relation with the roll 26 and substantially parallel to its axis. The deflector strip extends along the bar for at least the width of the web 28 to be dispensed from the device and has the cross sectional shape illustrated in Fig. 2. It comprises a rebate 31 extending along its edge adjacent the roll and this rebate is connected to the opposite edge of the strip by a convexly curved surface 32. The rebate forms a substantially straight edge 33 adjacent the roll which may be engaged with the web 28 dispensed from the roll, and this straight edge is contiguous with the convexly curved surface 32 which extends away from the roll.

   When the device is to be used to wrap a load, such as a stack of goods on a pallet, the web 28 is led over the deflector strip 30, as illustrated in Fig.
2. 2. A device for wrapping a load with a web of stretchable wrapping material constructed and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.

   2, and its leading edge is fixed to the top or bottom of the load. To facilitate pulling of the web from the roll for this operation, the fastener 10 is only tightened sufficiently to retain the roll securely mounted in the device and not to apply any significant degree of drag to the web. Having attached the web to the load, the operator grips the device by the upright 3 and walks around the load so as to allow the web to be pulled from the roll and produce a spiral wrap of overlapping turns about the load. In order to achieve the desired amount of stretch in the wrapped turns, a suitable braking force must be applied to the web as it is pulled from the roll. This determines the tensile force required to pull the web from the roll and, hence, the degree of stretch applied to the web.A suitable braking force is applied to the web by engaging the deflector strip 30 with the web and deflecting it from the direct path of travel between the roll and the load. The web firstly engages the sharp edge 33 of the deflector strip which applies an initial drag, and, thereafter, the degree of drag can be progressively increased by turning the device so as to engage more of the deflector curved surface 32 with the web. The deflector strip also prevents the web from necking-in to any significant extent. The action of the deflector strip is assisted by the web also engaging the inner edge of the upright 4, as illustrated in Fig. 2. If required, the fastener 10 may be used for making fine adjustments to the drag appliej to the web and, once these have been made, no further adjustment of the fastener may be required during the life of the roll 26.The degree of stretch may be simply and rapidly adjusted by the operator manipulating the holder to change the width of the zone of contact of the deflector strip with the web.

   Whilst a particular embodiment has been described it will be understood that modifications can be made without departing from the scope of the invention.

   Claims (Filed on 23 Nov 82) 1 A device for wrapping a load with a web of stretchable wrapping material dispensed from a roll of the material mounted in the device, in which a deflector member is disposed in spaced relation with the roll substantially parallel to the axis thereof, and is constructed and arranged so that the web dispensed from the roll may be engaged progressively against the deflector surface by moving the deflector member so as to deflect the path of travel of the web pulled from the roll.