WO1992021566A1

WO1992021566A1 - Bread unwrapping apparatus

Info

Publication number: WO1992021566A1
Application number: PCT/AU1992/000263
Authority: WO
Inventors: John Petrevski; Ray Gordon
Original assignee: George Weston Foods Limited
Priority date: 1991-06-07
Filing date: 1992-06-04
Publication date: 1992-12-10

Abstract

A device to remove bread from its wrapper so that the bread may be recycled. Wrapped bread moves on conveyor (11) between vertical guide plates (not shown). A horizontal rotating disc blade (12), the radius of which extends right across the bread, slices through the lower part of the loaf including slitting the front and sides of the wrapper. However, the rear face of the wrapper is not cut and on subsequent movement of the article the intact but open wrapper adheres to upper conveyor (14) due to vacuum from chamber (15) whilst the bread drops onto lower conveyor (16). A chute (17) supplied with air from duct (18) draws the wrapper away on release from the vacuum of belt (14). Alternatively a pair of horizontal disc blades may be used. These are mounted on arms which pivot from opposite sides of conveyor (11) and cooperate to cut the face of the wrapper and then their respective sides thereof - thus avoiding cutting the bread itself. Bandsaws may be used in place of cutting discs and vacuum may be used, instead of an air blast, to remove the wrappers.

Description

BREAD UNWRAPPING APPARATUS This invention relates to the removal of bread from its wrapper in order that the bread may be recycled. In particular, this invention relates to apparatus for unwrapping bread which enables the wrapper to be separated from its contents. Traditionally the removal of bread from its wrapper was a laborious manual operation which, apart from being slow, was also dangerous for the operator who had to apply a sharp instrument to the wrapper so as to perforate the wrapper and remove the bread therefrom.

One improvement to this traditional method is described in US patent 4219299 (Watson). An apparatus is described therein which conveys wrapped bread across a stationary knife blade which in turn longitudinally slits the wrapper on its lower surface from one end to the other. The wrapper, having been caught between a pair of V- belts trained around a corresponding pair of idler pulleys before passing over the knife blade, is then pulled upwardly and away from the bread. The bread continues on to a take- away conveyor for further processing.

The difficulty with this apparatus is that frequently, the slit provided in the wrapper by the knife blade is not sufficiently wide to allow the full contents of the wrapper to be removed. It is common therefore that some bread will remain in the wrapper and before the wrapper can be disposed of, the bread removal must be manually completed by an operator. A second difficulty is that, to be effective, stationary blades need to be kept extremely sharp. If they are not sharp, they will not reliably cut the bread wrapping material. As a result the blade needs to be continually replaced with a sharpened blade to try to maintain reliability in opening and removal of the wrapping material. Whilst this automated process is certainly faster than an entirely manual operation, its reliability is low and hence a manual operator is constantly .required to ensure quality control. The requirement of a manual operator also detracts from a reduction in the operating costs of the apparatus.

Accordingly, it is an object of this invention to provide a bread unwrapping apparatus which substantially alleviates the difficulties of the prior art. In particular, it is an object of this invention to provide a bread unwrapping apparatus which enables bread to be wholly removed from its wrapper without manual interference by an operator.

According to a first aspect of the present invention there is provided apparatus for reliably opening a wrapper on a wrapped bread article to enable subsequent removal of the bread from said wrapper, said apparatus comprising means for creating relative movement between said wrapped bread article and cutting means, characterised in that said cutting means comprises at least one rotating cutting element.

According to a second aspect of the invention there is provided apparatus for reliably opening a wrapper on a wrapped bread article to enable subsequent removal of the bread from said wrapper, said apparatus comprising means for creating relative movement between said wrapped bread article and cutting means, characterized in that said cutting means is adapted to substantially open at least one face of the wrapper.

This aspect of the invention is predicated on the discovery that by the provision of cutting means which enables the bread wrapper to be opened across one entire face of its surface, the bread can be easily and wholly removed without the assistance of a manual operator.

In a preferred embodiment of the second aspect of the invention, the cutting means is characterized in that it is a rotating cutting element. With respect to both aspects of the invention a rotating cutting element has surprisingly been found to not suffer from the need to be kept sharp to reliably cut and open a wrapper on wrapped bread.

Preferably said means for creating relative movement between said wrapped bread article and said cutting means comprises conveyor means.

In another embodiment of this invention said cutting means is arranged to make a continuous cut in said wrapper with a first portion of said cut extending longitudinally along said wrapped bread article over substantially the length of said wrapped bread article, a second portion of said cut extending transversely across said wrapped bread article over substantially the width of said wrapped bread article, and a third portion of said cut spaced from and generally parallel to said first portion of the cut extending longitudinally along said wrapped bread article over substantially the length of said wrapped bread article. This arrangement is particularly useful since it prevents the lower surface of the bread article being severed in addition to edges of said bread wrapper.

Preferably said cutting means comprises a pair of rotating cutting elements conveniently positioned so as to sever the bread wrapper along a forward edge and then to each sever a side edge of said bread wrapper. In this embodiment the load on the rotating cutting means is further reduced owing to the duplicity of elements thereby slowing the rate of blunting of the elements. Furthermore, the decreased load on each element assists in reducing friction thus enabling the operating temperature of the elements to be at a lower level than normally expected. At least one of said pair of rotating cutting elements may be adapted so as to move transversely relative to said conveyor means. This arrangement is useful since it allows the apparatus to process bread articles of varying width.

Said rotating cutting means are preferably adapted to rotate in a plane parallel to the at least one face of said wrapper opened by said cutting means.

Preferably the relative horizontal movement of each of the pair of rotating cutting elements occurs by means of air cylinders or other suitable means, which means may be triggered by a sensor or other appropriate means in the apparatus which detects the approach of a wrapped bread article. In a further embodiment of the invention, the means for creating relative movement between said wrapped bread article and said cutting means comprises a lower, in-feed conveyor having upper and lower runs, said upper run being driven so as to carry articles thereon towards said cutting means. in all aspects of the invention, cutting means is preferably located adjacent the upper run of the lower conveyor and more preferably is located such that a cutting edge extends across a width of the lower conveyor at a height of between 15 and 40 millimetres above the upper run of the lower conveyor. Preferably the height of said blade is between 25 and 35 millimetres above the upper run of the lower conveyor. Most preferably, the height of the cutting edge above the upper run of the lower conveyor is 30 millimetres. The height of the cutting edge above the upper run of the lower conveyor is most conveniently adjustable.

In a preferred embodiment of the invention, the cutting means rotates such that its cutting zone moves in the same general direction as the upper run of the lower conveyor. The cutting means should preferably rotate at such a speed that the cutting edge thereof is not worn by its interaction with the wrapped bread, but also so that its relative bluntness does not effect the efficiency of its cutting action. The cutting means may be formed by one disc or a pair of discs which is caused to rotate such that its outer peripheral cutting edge travels at a rate of 700-1200 revolutions per minute, preferably 800-1000 revolutions per minute. Additionally, the in-feed lower conveyor may be provided in the region of the cutting means with upstanding guide plates located on each side of the upper run of the lower conveyor so as to maintain correct orientation of the bread through the cutting means.

In another embodiment of the invention there is preferably provided means for creating relative movement between an opened wrapper and unwrapped bread so as to assist the opened wrapper to be separated from the unwrapped bread.

Preferably the means for creating relative movement between the opened wrapper and the unwrapped bread comprises an upper conveyor having a bread engaging lower run driven so as to travel away from the cutting means. The bread engaging lower run of the upper conveyor is conveniently displaced vertically from the upper run of the lower conveyor by a height substantially equivalent to the height of the bread being processed. The vertical distance between the upper and lower conveyors may be adjustable so as to accommodate different sized bread articles. The upper conveyor may be a square bar mesh, preferably having apertures of approximately 4mm². It should be noted that in order to maximise the efficiency of the upper conveyor in taking away the opened wrapper, the mesh preferably should be as open weave as possible without permitting the opened wrapper to become entrapped therein.

In one aspect of the invention, the bread entry end of the upper conveyor is located subsequent to the position of the cutting means of the apparatus. Said upper conveyor is preferably associated with a vacuum chamber adapted to assist in separating the wrapper from the bread. In this embodiment, the upper conveyor is provided with perforations throughout its length so as to enable the vacuum from the vacuum chamber to act upon the opened wrapper. When the wrapper reaches the end of the upper conveyor remote from the bread entry end it is released from the vacuum by means obstructing the vacuum and in this manner the opened wrapper can be caused to be taken away from the unwrapped bread.

As an adjunct in disassociating the bread from its wrapper the lower conveyor preferably transfers the unwrapped bread to an aligned take-away conveyor which is vertically displaced below the level of the upper run of the lower conveyor. By force of gravity, the unwrapped bread drops out of the aperture formed by the cutting means in the lower surface of the bread wrapper onto the take-away conveyor thereby causing separation of the bread from its wrapper, which wrapper is concurrently being held by the vacuum of the vacuum chamber acting through the perforated lower run of the upper conveyor. Most preferably, the conveyors operate at a speed of approximately metre per second.

Conveniently, the end of the upper vacuum chamber associated, conveyor remote from the bread entry end is provided adjacent this same end with a bag exhaust chute.

Said bag exhaust chute is associated with an air duct which channels air through the chute from the end associated with the upper conveyor to a disposal point. When the vacuum ceases to act upon the wrapper by virtue of the obstruction means at the end of the upper conveyor, the wrapper is disassociated from the upper conveyor and is drawn away by the air stream through the bag exhaust chute for disposal purposes. If necessary, the force of the air duct upon the wrapper can be augmented by an air jet directing air into the bag exhaust chute in the direction of wrapper disposal.

In order to ensure efficiency of disposal of the opened wrapper, the apparatus according to the invention may also be provided with means to detect the non-separation of the bread from its wrapper. Preferably said means comprises at least one eye adapted to cause shutdown of the apparatus should it not detect the passage of an opened wrapper along the upper vacuum associated conveyor.

More preferably, said means for detection of the non-separation of the opened wrapper from the bread comprises a pair of electronic eyes, the first located adjacent the upper vacuum associated wrapper and adapted to detect the passage of the opened wrapper, and the second located adjacent said aligned takeaway conveyor and adapted so as to detect the passage of the unwrapped bread. In this embodiment, should both electronic eyes not detect the passage of the unwrapped bread and the opened wrapper, an associated circuit remains incomplete and the apparatus is shut down to enable recovery of the opened wrapper.

The one preferred aspect of the invention will now be described with reference to the accompanying illustrations in which:

Figure 1 represents a schematic sectional view of the apparatus according to a first preferred embodiment of the invention;

Figure 2 represents a sectional view of the apparatus taken through the line AA of Figure 1 ; Figure 3 represents a schematic plan view of a second preferred embodiment of the present invention; and

Figure 4 represents a schematic elevation view of the embodiment of Figure 3.

A bread unwrapping apparatus 10 is provided with a lower in-feed conveyor 11 which delivers the wrapped bread by virtue of its upper run 11a to the cutting means 12. The wrapped bread is maintained in a position aligned with the conveyor 11 by guide plates 13a and 13b positioned on each side of the in-feed conveyor 11. The cutting means 12 which may be a horizontal rotationally driven blade which extends across the width of the in-feed conveyor 11 , may rotate at a speed of 2000 metres per minute, a speed slightly greater than the speed of the in-feed conveyor 11. The rotationally driven blade may be located at approximately 30 millimetres above the height of the upper run 11a of the lower in-feed conveyor 11. The height of the rotationally driven blade, 12 above the upper run 11a of the lower conveyor 11 is adjustable. The rotationally driven blade removes the lower face of the bread wrapper from proximity with the bread by severing the forward and side edges of the wrapper but leaving the trailing end edge 5 intact.

The bread, with an intact but opened wrapper is conveyed past the cutting means 12 by the upper run 11a of the in-feed lower conveyor 11 wherein it comes into contact with the lower run 14a of the upper conveyor 14. The vertical displacement of the lower run 14a of the upper conveyor 14 above the upper run 11a of the lower in-feed 1 0 conveyor 11 is substantially equivalent to the height of the bread and is adjustable so as to cope with different types of the sizes of bread input. The upper conveyor 14 is perforated throughout its length so as to enable an associated vacuum chamber 15 to act upon the bread wrapper.

As an adjunct to the action of the vacuum associated perforated upper conveyor 1 5 14 upon the bread wrapper, the lower conveyor 11 transfers the unwrapped bread to an aligned endless take-away conveyor 16 travelling away from the bread unwrapping apparatus 10.

This take-away conveyor 16 is vertically displaced below the lower in-feed conveyor 11 thereby enabling the bread to drop by force of gravity of the end of the in- 0 feed conveyor 11 on to the take-away conveyor 16 for further processing.

The wrapper, now devoid of bread is carried to the end 14b of the lower run 14a of the upper conveyor 14 which end is remote from the entry end of the apparatus and horizontally displaced from the end of the lower conveyor 11 by a distance greater than the length of the bread input. At this end 14b of the upper conveyor 14, the vacuum 5 from the vacuum chamber 15 ceases to act through the perforated upper conveyor 14 thereby releasing the wrapper from contact with the conveyor 14. A bag exhaust chute 17 with air channelled through it by virtue of air duct 18 is located adjacent the end 14b of the lower run 14a of the upper conveyor 14 so as to draw away the waste wrapper when it is released from the vacuum created by the vacuum chamber 15. The 0 wrapper is then drawn away to a disposal point not illustrated.

A second preferred aspect of the invention will now be described with reference to Figures 3 and 4. A bread unwrapping apparatus 100 is provided with a lower in-feed conveyor 110 which delivers the wrapped bread by virtue of its upper run 110a to the cutting means 112. The cutting means 112 comprises a pair of horizontal rotationally 5 driven disc blades 112a and 112b which extend across the width of the in-feed conveyor 110. The blades may rotate at a speed of 2000 metres per minute, a speed greater than the speed of the in-feed conveyor 110. The rotationally driven blades 112a and 112b may be located at approximately 30 millimetres above the height of the upper run 110a of the lower in-feed conveyor 110. The height of the rotationally driven blades, 112a 5 and 112b above the upper run 110a of the lower conveyor 110 is adjustable. The rotationally driven blades remove the lower face of the bread wrapper from proximity with the bread by severing the forward and side edges of the wrapper but leaving the trailing end edge intact.

The rotationally driven blades 112a and 112b are mounted on arms 119a and

1 0 119b respectively which are pivoted at 120a and 120b respectively on opposite sides of the conveyor 110. The arm 119a locates, in a rest position, the leading blade 112a over the edge of the conveyor 110 distant from the pivot axis 120a. Similarly the arm 119b locates (as illustrated), the blade 112b over the edge of the conveyor 110 distant from the pivot axis 120b. Actuations 113a and 113b are provided to pivot the arms 119a and

1 5 1 19b respectively about pivot axis 120a and 120b as described hereinafter. In operation, the actuators 113a, 1 13b move the arms 119a and 1 19b outwardly in response to a wrapped bread loaf triggering a sensor (not shown). This movement causes the blades to traverse the width of the conveyor 110 thereby ensuring the leading lower end edge of the wrapping bag is cut. Thereafter the two blades are held at an outer 0 position whereby the peripheral cutting edge of the blades is positioned to enter only a small distance into the wrapped bread loaf so that the lower side edges of the wrapper are cut by a respective one of the blades. If desired, only the leading blade 112a might perform the aforesaid complete transverse movement across the conveyor, however, in this embodiment it is necessary that the blades are positioned at the appropriate time to 5 cut the lower side edges of the wrapping bag. When the bread loaf has passed the cutting blades 112a, 112b, the actuators 113a and 113b are reversed so that the rotationally driven blades 112a and 112b are moved back to the rest position illustrated. The degree of horizontal movement of each of the rotationally driven blades 112a and 112b may be adjusted so as to enable the apparatus to cater for bread products of differing sizes. 0 This embodiment has the advantage over that illustrated in Figures 1 and 2 in that the blades do not need to slice through the lower surface of the bread in the wrapping bag. Subsequent to passing the cutting blades 112a, 112b, the apparatus is similar to the earlier embodiment in that the opened wrapper is conveyed by the lower conveyor 110 and subsequently also via the upper conveyor 114 when it comes into contact with 5 its lower run 114a. The vertical displacement of the lower run 114a of the upper conveyor 114 above the upper run 110a of the lower in-feed conveyor 110 is substantially equivalent to the height of the bread and is adjustable so as to cope with different types of the sizes of bread input. The upper conveyor 114 is perforated throughout its length so as to enable an associated vacuum chamber 115 to act upon and hold the bread wrapper within the zone of the chamber 115.

As an adjunct to the action of the vacuum associated perforated upper conveyor 114 upon the bread wrapper, the lower conveyor 110 transfers the unwrapped bread to an aligned endless take-away conveyor 116 travelling away from the bread unwrapping apparatus 100. This take-away conveyor 116 is vertically displaced below the lower in-feed conveyor 110 thereby enabling the bread to drop by gravity at the end of the in-feed conveyor 110 on to the take-away conveyor 116 for further processing.

The wrapper, now devoid of bread is carried to the end 114b of the lower run 114a of the upper conveyor 114 which end is remote from the entry end of the apparatus and horizontally displaced from the end of the lower conveyor 110 by a distance greater than the length of the bread input. At this end 114b of the upper conveyor 114, the vacuum from the vacuum chamber 115 ceases to act through the perforated upper conveyor 114 thereby releasing the wrapper from contact with the conveyor 114. A bag exhaust chute 117 with air channelled through it by virtue of air duct 118 is located adjacent the end 114b of the lower run 114a of the upper conveyor

114 so as to draw away the waste wrapper when it is released from the vacuum created by the vacuum chamber 115. The wrapper is then drawn away to a disposal point not illustrated.

It can be seen that this bread unwrapping apparatus has advantages over the proposal of the prior art inasmuch as, due to its removal of an entire lower .face of the bread wrapper, the bread can be easily and wholly removed without intervention by a manual operator. By virtue of this apparatus, bread can be more quickly processed and indeed more safely processed due to the lack of interaction between a manual operator and any hand-held cutting blade. It will be appreciated that various modifications may be made to the above described embodiments without departing from the scope of the invention. For example, cutting means comprising a band saw reciprocating at great speed at the same height as a rotationally driven blade will have a similar effect on the lower face of the bread wrapper thereby enabling whole and easy removal of the bread contents. Another alternative envisaged to this apparatus but within the scope of the invention is the use of a vacuum driven exhaust chute for channelling away of the waste wrappers rather than the use of an air duct driven chute.

Whilst the invention has been described with particular reference to the unwrapping of bread, it is to be understood that the invention is not limited to the bread unwrapping field but may also be applied to situations in which a similar apparatus is required.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1 . Apparatus for reliably opening a wrapper on a wrapped bread article so as to enable subsequent removal of bread from said wrapper, said apparatus comprising means for creating relative movement between said wrapped bread article and cutting means, characterised in that said cutting means is adapted to substantially open at least one face of said wrapper.

2. Apparatus as claimed in Claim 1, wherein said cutting means comprises at least one rotating cutting element.

3. Apparatus as claimed in Claim 1 or Claim 2 wherein said means for creating relative movement between said wrapped bread article and said cutting means comprises conveyor means.

4. Apparatus as claimed in Claim 3, wherein said cutting means is in a plane parallel to an upper run of a lower conveyor of said conveyor means for creating relative movement between said wrapped bread article and said cutting means.

5. Apparatus as claimed in Claim 1 wherein said cutting means is arranged to make a continuous cut in said wrapper with a first portion of said cut extending longitudinally along said wrapped bread article over substantially the length of said wrapped bread article, a second portion of said cut extending transversely across said wrapped bread article over substantially the width of said wrapped bread article, and a third portion of said cut spaced from and generally parallel to said first portion of the cut extending longitudinally along said wrapped bread article over substantially the length of said wrapped bread article.

6. Apparatus as claimed in Claim 5 wherein said cutting means comprises a pair of rotating cutting elements.

7. Apparatus as claimed in Claim 6 wherein said cutting elements are adapted to rotate in a plane parallel to the at least one face of said wrapper opened by said cutting means.

8. Apparatus as claimed in Claim 7 wherein at least one of said cutting elements being adapted for movement in a transverse direction relative to said conveyor.

9. Apparatus as claimed in Claim 1 or Claim 2, wherein said cutting means is located such that a cutting edge extends across a width of said lower conveyor at a height of 15-40 mm above a conveyor surface supporting said wrapped bread.

1 0. Apparatus as claimed in any one of Claims 1 to 9 further comprising a vacuum- associated conveyor means for creating relative movement between an opened wrapper and bread within said opened wrapper so as to assist removal of said opened wrapper.