WO2001087713A1

WO2001087713A1 - Stack retaining means and method for delivering stacked articles

Info

Publication number: WO2001087713A1
Application number: PCT/GB2001/002160
Authority: WO
Inventors: Richard Humphrey Haynes
Original assignee: APV Systems Ltd; APV Ltd
Current assignee: SPX Flow Technology London Ltd
Priority date: 2000-05-19
Filing date: 2001-05-16
Publication date: 2001-11-22
Anticipated expiration: 2002-11-19
Also published as: GB0012015D0; AU2001256519A1

Abstract

A magazine assembly (20) comprises a set of guide rods (22) located each side of the stack (6), an outer guide rod (23), a support slide (24) and an adjustable stripping gate (5). The magazine assembly (20) is formed with an initial bend (26), an intermediate straight portion (27), a first curved portion (28) and a lower second curved portion (29) that is set back from the first curved portion. The support slide (24) extends radially through the bend (26) along the intermediate straight portion (27) and through the first curved portion (28) up to the second curved portion (29). As the outer guide rod (23) passes through the first curved region (28) the rod (23) extends through a first arc. As the rod (23) passes through the second curved portion region (29) the rod (23) extends through a second arc that is in the reverse direction to the first arc. As the stack of shells (6) passes through the first curved region (28) they substantially follow the arc defined by the curved support (24) until they are substantially horizontal and travelling in a substantially vertically downward direction. The stack of shells (6) continues in a downward direction until they abut the second arc of the guide rod (23) at which point the stack of shells are forced in reverse arc direction. The action of the stack of shells (6) being subjected to a gentle reverse curve path tends to release the wedging force that has built up in the stack.

Description

STACK RETAINING MEANS AND METHOD FOR DELIVERING STACKED ARTICLES

The present invention relates to stack retaining means and method for delivering stacked articles and is concerned particularly, although not exclusively with, a stack retaining magazine and method for delivering stacked delicate or fragile planar articles, such as biscuits.

Biscuit shells delivered from a post oven cooling band are conventionally overlap layered or 'shingled' in rows gradually standing up to an on-edge stack or 'penny stack' . The stack is then fed to one or more curved magazines that guide the stacked biscuits to a lower horizontal or near horizontal plane from where the individual shells are stripped out from the stack. The shells are stripped out or de-stacked one at a time so that they can be phase fed to a second process equipment.

The conventional magazines have an inherent problem of a build-up of pressure that is transmitted through the stack of shells. The pressure causes the shells to become wedged together. The wedging of the shells tends to jam the process flow.

According to a first aspect of the present invention there is provided retaining means for conveying a stack of articles, the retaining means comprising a first curved portion, and a second curved portion that is offset from the first curved portion and is curved in a reverse direction to the first curved portion, the arrangement being such that, in use wedging forces of the stack of articles within the retaining means are reduced.

Preferably, the first curved portion is adjacent to the second curved portion. The second curved portion is preferably located below the first curved portion of the retaining means.

The second curved portion is preferably not aligned with the tangent of the end of the first curved portion.

According to a second aspect of the present invention there is provided a method for delivering stacked articles, the method comprising releasing the wedging forces of a stack of articles that are contained within a curved stack retaining magazine by subjecting a part of the stack to a curve in the reverse direction to the main curve of the stack retaining magazine.

Preferably, the method comprises subjecting a portion of the stack of articles to a curve in a first direction, then subjecting the portion of articles to a curve in a reverse direction, the arrangement being such that the curve in the first direction has a greater radius of curvature than the curve in the reverse direction.

The invention may include any combination of the features or limitations referred to herein.

The present invention may be carried into practice in various ways, but an embodiment will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 shows a side view of a known conventional curved magazine assembly and de-stacking means; Figure 2 shows a side view of a first embodiment of a stack retaining magazine according to the present invention and de- stacking means;

Figure 3 shows a aside view of a second embodiment of a stack retaining magazine according to the present invention and de- stacking means; and

Figure 4 shows a side view of the lower portion of the magazine and an alternative de-stacking means.

Referring to the Figures 1 , a conventional biscuit magazine assembly 1 comprises a set of curved guide rods 2, a curved support slide 4 and an adjustable strip out gate 5 located at the lowermost end of the magazine assembly 1. In use biscuit shells 6 are delivered to the entrance of the magazine assembly 1 by an infeed drive belt 8. The shells 6 are initially overlapped or 'shingled' as they travel on the drive belt 8. As the shells 6 approach the entrance of the magazine they are gradually lifted to a vertical orientation such that they are stood up on one edge so forming a 'penny stack'. The shells 6 are removed from the magazine assembly 1 by a de-stacking stripping belt assembly 7 located below the magazine assembly 1. The stripping action of the belt assembly 7 is described in the UK patent specification No 2296914. The skilled person in the art will appreciate that any other suitable de-stacking apparatus can be used to strip the stacked articles from the magazine assembly 1. One such alternative de-stacking apparatus is shown in Figure 4. This de-stacking apparatus comprises a known pin chain strip-out system 9.

The length 'v' of the penny stack entering the magazine assembly 1 can be adjusted to vary the storage capacity. Typically 'v' can vary up to 20 metres in length. The length of the penny stack is increased to provide a cushion between short-term stoppages of secondary process equipment and the need to stop upstream baking equipment. Increasing the speed of the operation of the secondary process equipment can reduce the storage capacity.

As the penny stack proceeds through the magazine 1 it has to generally follow the curvature of the guide rods 2 and the support slide 4. When the length of the penny stack is increased the pressure on the shells entering the magazine causes a wedging pressure through the curve of the magazine. This wedging pressure restricts the free movement of the stack 6 through the magazine 1. A curved space 10 is provided above the radially outermost edge of the stack of shells 6. The space 10 is provided for the infeed overpressure stack deformation caused by the build-up of pressure.

In use the stripping assembly 7 causes the lower shells 6 in the stack to press against the adjustable stripping gate 5 and the additional pressure generated retards the fall of the contact edges of the shells 6. The combination of the additional pressure generated by the stripping gate and the wedging pressures generated within the stack of shells 6 distorts the intended presentation of the shells to the stripping surface 12 of the de- stacking assembly 7 and such distortion can cause jamming of the shells 6 against the stripping gate 5.

Referring to Figure 2 a magazine assembly 20 comprises a set of guide rods 22 located each side of the stack 6, an outer guide rod 23, a support slide 24 and an adjustable stripping gate 5. The magazine assembly 20 is formed with an initial bend 26, an intermediate straight portion 27, a first curved portion 28 and a lower second curved portion 29 that is set back from the first curved portion. The support slide 24 extends radially through the bend 26 along the intermediate straight portion 27 and through the first curved portion 28 up to the second curved portion 29.

Below the lowermost end of the support slide 24 there is a straight support slide 30 the uppermost end of which abuts an end portion of the support slide 24. The distance 'x' represents the set-back gap between the radially innermost edges of the stack of shells 6 as they leave contact with the curved support 24 and the vertically innermost surface of the support slide 30.

As the outer guide rod 23 passes through the first curved region 28 the rod 23 extends through a first arc. As the rod 23 passes through the second curved portion region 29 the rod 23 extends through a second arc that is in the reverse direction to the first arc.

As the stack of shells 6 passes through the first curved region 28 they substantially follow the arc defined by the curved support 24 until they are substantially horizontal and travelling in a substantially vertically downward direction. The stack of shells 6 continues in a downward direction until they abut the second arc of the guide rod 23 at which point the stack of shells are forced in reverse arc direction. The action of the stack of shells 6 being subjected to a gentle reverse curve path tends to release the wedging force that has built up in the stack.

The distance 'x' could be adjustable to increase the level of control. The optimum distance for this particular embodiment is 8mm. As the distance 'x' is reduced to zero, the shells 6 that are being fed to the de- stacking assembly 7 begin to wedge on the stripping gate 5. As the distance 'x' is increased above 8mm the shells 6 tend to wedge on the guide rod 23 and the edges of the shells 6 tend to fan upwards. If the distance 'x' was increased further the edges of the shells would reach a position where they would not drop downwards in time for the de- stacking assembly to successfully contact them.

With reference to Figure 3, the de-stacking assembly 7 and the lowermost portion of the stack are both at an angle from the vertical. The uppermost surface of the belt of the de-stacking assembly 7 is located at an inclined angle to the lowermost portion of the stack 6 within the magazine 1. The benefits of the action of the stack 6 being subjected to a gentle reverse curve path tending to release the wedging force are also experienced by this arrangement.

Claims

1. Retaining means (1) for conveying a stack of articles (6) , the retaining means (1) comprising a first curved portion (28), and a second curved portion (29) that is offset from the first curved portion (28) and is curved in a reverse direction to the first curved portion (28), the arrangement being such that, in use wedging forces of the stack of articles (6) within the retaining means (1) are reduced.

2. Retaining means (1) as claimed in claim 1, wherein the first curved portion (28) is adjacent to the second curved portion (29) .

3. Retaining means (1) as claimed in claim 1 or claim 2, wherein the second curved portion (29) is located below the first curved portion (28) of the retaining means (1).

4. Retaining means (1) as claimed in any one of claims 1 to 3, wherein the second curved portion (29) is not aligned with the tangent of the end of the first curved portion (28) .

5. A method for delivering stacked articles, the method comprising releasing the wedging forces of a stack of articles (6) that are contained within a curved stack retaining magazine (20) by subjecting a part of the stack (6) to a curve (29) in the reverse direction to the main curve (28) of the stack retaining magazine (20).

6. A method for delivering stacked articles, as claimed in claim 5, wherein the method comprises subjecting a portion of the stack of articles (6) to a curve (28) in a first direction, then subjecting the portion of articles to a curve (29) in a reverse direction, the arrangement being such that the curve (28) in the first direction has a greater radius of curvature than the curve (29) in the reverse direction.