GB2384765A

GB2384765A - Alignment of a moving item with a moving carriage prior to cutting

Info

Publication number: GB2384765A
Application number: GB0202413A
Authority: GB
Inventors: Peter Bell
Original assignee: ADVANCED FOOD TECHNOLOGY Ltd
Current assignee: ADVANCED FOOD TECHNOLOGY Ltd
Priority date: 2002-02-01
Filing date: 2002-02-01
Publication date: 2003-08-06
Also published as: WO2003064299A1; GB0202413D0; EP1499546A1; CA2506530A1

Abstract

An automatic aligning apparatus comprises conveyance means 1, article 4 position sensing means 9 and alignment means 7a, 7b, 7c, 7d, with associated actuating 8a, 8b and control means 14, mounted on a moveable carriage 6 such that the article 4 is aligned as the carriage 6 and article move together along a production line. Also disclosed is a method associated with the aforementioned apparatus in which the article 4 is aligned as previously described. The article 4 may be a substantially flat article 4 such as a generally rectangular or square sandwich 4 which, once a diagonal of which has been aligned with the direction of travel, may be cut along its diagonal by a blade 5 on the same production line. Alignment may be seen in the transition from fig.3a to fig.3b. A front pair of the alignment means 7a, 7c abut the article 4, a rear pair of the alignment means 7b, 7d moving inwards relative to the direction of travel of the article 4 to align the article 4. The sensing means 9 may be a photoelectric sensor 9. The actuators 8a, 8b may be pneumatic rams 8a, 8b. The apparatus may align and cut a stack of articles 4 at once.

Description

AUTOMATIC ALIGNMENT APPARATUS AND METHOD The invention relates to an automatic alignment apparatus and method for flat polygonal articles. It is particularly suitable for situations where it is desired that the article is to be correctly aligned before being cut. This includes devices such as sandwich cutters where a substantially square sandwich is cut in half diagonally.

Prepackaged sandwiches represent a huge commercial market, and a large proportion of these comprise two substantially square slices of bread enclosing a filling. Such sandwiches are often cut in half diagonally and sold in triangular prismatic packs. It is therefore advantageous to use a device which cuts these sandwiches automatically. It is important that these devices align the sandwiches so that they are accurately cut from comer to comer.

Automatic cutting devices for sandwiches, particularly those suitable for use on production lines are known. In one such device sandwiches arranged so as to have one comer pointing roughly in the direction of travel, and so forming the leading comer of the sandwich, are conveyed towards a precision alignment section comprising a pair of gates. Each gate is oriented at 45 degrees to the direction of travel. When they are closed the gates resemble a funnel in the direction of travel. As the sandwich travels along the production line it runs up against the gates and stops.

The leading comer is guided into the apex of the funnel formed by the gates. When it is determined by a sensor that the sandwich is correctly aligned the gates open to allow the sandwich to travel down the device to the cutting section. A disadvantage is this method is that sandwiches made of bread slices which are not precisely square may not be accurately cut from corner to comer.

A second device is known in which the sandwich is conveyed into an alignment section comprising four fingers. An example of such a device is the "Sandwich Aligner and Cutter"manufactured by Advanced Food Technology. The fingers are arranged in two pairs. One pair located downstream contacts the leading comer of the sandwich (as referred to above) and another pair located upstream

aligns the trailing comer of the sandwich. When a sandwich on a passing conveyor belt is in position for alignment each pair has one finger either side of the sandwich, on a respective line perpendicular to the direction of travel. The downstream pair is roughly aligned with the leading comer of the sandwich and the downstream pair is roughly aligned with the trailing comer. A sandwich in position for alignment is detected by a photocell. The sandwich is paused briefly and lifted, with the conveyor belt, into an alignment position whereupon the fingers of each pair close together, perpendicular to the direction of travel, to align the comers of the sandwich precisely.

When it is determined that the sandwich is correctly aligned, the sandwich is released by the fingers and, again with the conveyor belt, drops free of the fingers to be conveyed towards the cutting section.

The fingers of each pair can be adjusted using an eccentric cam arrangement to ensure that when they close, the sandwich is perfectly aligned before starting the cutting process.

In any production line it is desirable to provide as large a throughput as possible. One way in which throughput can be increased is to stack the sandwiches so that more than one sandwich is cut for each alignment and cutting cycle. However, a problem inherent in both these devices is that the sandwich must pause briefly during the alignment process. It is an object of the present invention to solve this problem.

Accordingly, the present invention provides an automatic aligning apparatus for aligning a substantially flat article comprising; conveyance means acting on the bottom of said article to convey said article through the apparatus, sensing means to sense when said article is in position for alignment, alignment means to align said article when said sensing means sense it is in position, at least one actuator to move said alignment means so as to align said article correctly, and control means to control said at least one actuator; characterised in that, said alignment means is mounted on a carriage, and in that

said carriage moves said alignment means at a speed substantially the same as that of said article while alignment is carried out.

The present invention also provides a method of aligning a substantially flat article moving along a production line comprising the steps of : determining whether said article is in position to be aligned, when it is determined that said article is in position to be aligned, moving a carrier, on which is mounted alignment means, at a speed substantially the same as that of said article, effecting the alignment of said article while said carrier is moving, and returning said carrier to said position when said alignment of said article has been carried out.

In this way the present invention allows an article to be aligned without needing to stop it to carry out the alignment. This gives a greater throughput increasing production line efficiency.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which :- Figure I is a side elevation of the embodiment; Figure 2 is a cross section through one pair of pneumatic actuators; Figure 3a is a plan view of the alignment section of the embodiment, prior to aligning the article; and Figure 3b is a plan view of the alignment section of the embodiment, after aligning the article.

Figure I shows the overall arrangement of the apparatus. A belt I runs for the entire length of the apparatus, it includes an entry end and an exit end, and is used to convey through the apparatus the sandwich 4 to be cut. The sandwich 4 to be cut is placed on the belt I at the entry end so that one (leading) comer is pointing roughly

towards the exit end of the belt, leading the rest of the sandwich. The sandwich is then conveyed by the belt 1 into an alignment section 2 which positions the sandwich so that both the leading and the trailing comers are correctly aligned with the cutting blade 5 of the cutting section 3. A detailed description of the action of the alignment section is given below. As the sandwich leaves the alignment section 2 it enters the cutting section 3. The cutting section 3 cuts the sandwich in half from comer to comer. Finally, the cut sandwich leaves the apparatus via the exit end of the belt 1 (on the right of Figure 1) ready for packaging in a further section of the production line (not illustrated).

The construction and operation of the alignment section 2 will now be described in detail. As shown in Figure 3a, the sandwich 4 arrives in the alignment section roughly aligned with a leading comer at its front. The movement of four cylindrical fingers 7 then causes the sandwich 4 to be aligned as shown in Figure 3b.

The fingers 7 are connected to a carriage 6 and extend vertically with respect to the plane of the belt 1. They are pivotally connected to the carriage 6 allowing them to move in a plane normal to their axis. The external surface of each finger is enclosed by a freely rotatable sleeve. The fingers are arranged in two pairs. Each pair has one finger at either side of the belt 1 on a respective line perpendicular to the direction of travel 16. The two pairs are spaced apart by approximately the side dimension of the sandwich 4. Movement of the fingers 7 is actuated by a pneumatic ram 8 via an air supply 10. Each finger 7 has a bolt (not shown) which allows adjustment relative to its respective pneumatic ram 8. Although a pneumatic ram 8 has been used as an actuator in this embodiment, the person skilled in the art will appreciate that other actuators, for example a gearing system, could also be used.

Figure 2 illustrates the arrangement of one pair of fingers 7a, 7c either side of the belt. Each finger is moved by the pneumatic ram 8a and 8c respectively. Figure 2 shows two of the positions that can be adopted by the pair of fingers 7a and 7c. Solid lines indicate the position in which they are far apart. Dashed lines indicate the position in which they are close together.

The carriage 6 is mounted using a motorised gearing system onto the rack 12.

This allows the carriage 6, the attached fingers 7 and actuators 8 to move along the

belt in a controlled manner. The distance 15 that the carriage can move along the direction of travel 16 is typically 75 mm. Although rack system 12 is used to move the carriage 6 in this embodiment, the person skilled in the art will appreciate that an alternative system could also be used.

A stainless steel shelf 11 supports the sandwich as it travels through the alignment section. A photoelectric sensor 9 is provided on the side of the carriage 6 facing the belt I to detect when a sandwich 4 has entered the aligning section.

The operation of the alignment section 2 will now be described with reference to Figures 3a and 3b. Before a sandwich 4 is conveyed into the alignment section 2, the carriage 6 is positioned at the entry end of the rack 12 so that it can move along the rack 12 together with the sandwich 4 during the aligning process. (This is the position shown in Figure 1. ) The fingers 7 are positioned as follows (Figure 3a): the fingers 7a and 7c towards the exit end of the apparatus are spaced so as to intercept the leading comer of the sandwich 4. The fingers 7b and 7d towards the entry end of the apparatus are spaced apart by a great enough distance to ensure that the sandwich 4 can pass between them without being obstructed by these fingers.

When the photoelectric cell 9 indicates that a sandwich has entered the alignment section 2 and that one of its leading edges is in contact with either the finger 7a or 7c, the control system 14 operates to move the carriage 6 along the direction of travel 16 of the belt, at the same speed as the belt, towards the exit end of the apparatus. While the carriage 6 is in motion the control system sends a signal to the pneumatic rams 8 to cause them to move fingers 7b and 7d together. As fingers 7b and 7d move together one of them will come into contact with a trailing edge of the sandwich 4 and cause it to rotate on the belt 1. This will also cause rotation between the sandwich 4 and the fingers 7, which is accommodated by the rotatable sleeve.

When the motion of fingers 7b and 7d is complete the sandwich 4 has been rotated so that both of its comers are in alignment with the cutting blade 5 as shown in Figure 3b. The control system determines when the motion of the fingers 7b, 7d is complete and the sandwich 4 is aligned correctly.

If the sandwich had already been aligned it would have been contacted

simultaneously by the finger 7b and finger 7d and would not have been moved by them.

The control system 14 then sends a signal to the pneumatic rams 8 to cause them to stop moving fingers 7b and 7d together and instead move fingers 7a and 7c apart. Fingers 7a and 7c are moved far enough apart to ensure that the sandwich can pass through them unobstructed. When the control system 14 determines that fingers 7a and 7c are far enough apart, it sends a signal to the pneumatic rams 8 to stop all motion of the fingers 7.

The control system 14 then stops the motion of the carriage 6 towards the exit end of the apparatus and sends a signal to make it move towards the entry end of the apparatus back to its starting position. As the carriage travels back to the starting position the control system 14 determines from the photoelectric sensor 9 when the sandwich 4 is no longer located between the fingers 7. It then instructs the pneumatic rams 8 to move the fingers 7 so that fingers 7b and 7d are apart and fingers 7a and 7c are together as positioned at the start of the process.

The control system 14 stops the movement of the carriage 6 when it has travelled as far towards the entry end of the apparatus as the rack 12 allows it. The alignment process can then be repeated for the next sandwich which the belt 1 carries into the alignment section 2.

Although a certain pattern of operation of the fingers to align the sandwich has been described in this embodiment, the person skilled in the art will appreciate that other systems of moving the fingers will also achieve the same effect. The person skilled in the art will also appreciate that alternative alignment systems, for example one based on the gate system identified in the prior art, could also be mounted on the carriage instead of the finger system.

The construction and operation of the cutting section 3 will now be described.

The cutting section 3 includes an extra belt 13, which presses on top of the sandwich to ensure that the sandwich 4 remains in the correct alignment throughout the cutting process. The belt 13 moves in the same direction at the same velocity as belt 1.

Preferably, belt 13 is adjustable in height to accommodate the height of the sandwich 4 to be cut. If this is the case, the height adjustment also allows the cutting section 3

to cut a stack of more than one sandwich at a time, further increasing throughput.

Some distance along the cutting section 3 there is located a vertical blade 5.

The blade 5 is located in the centre of the belts I and 13 with its cutting edge facing towards the oncoming sandwich 4. The cutting edge may be designed to minimise the spreading of the sandwich fillings. For example, in this embodiment, the blade 5 is typically 0.5 mm thick. This allows the blade 5 to cut the sandwich 4 with minimal disturbance to the sandwich filling.

The blade 5 moves with a vertical reciprocating motion so as to cut the sandwich. To allow the blade 5 to operate without obstruction each of the belts 1, 13 are split la, lob in a longitudinal direction to allow the blade 5 free motion.

After the belts 1,13 have conveyed the sandwich 4 through the cutting section it exits the apparatus with a perfectly aligned comer-to-comer cut.

The present invention therefore achieves correct alignment of sandwiches with no need to pause the motion of the sandwich. The applicant has discovered that this allows a significant increase in the throughput of a cutting production line from typically 45 cycles per minute to typically 60 cycles per minute in the present invention.

Although the above described embodiment has related specifically to sandwiches, the person skilled in the art will realise that it could easily be adapted to cut any similar flat article from comer-to-comer. Likewise, although the alignment of a square item has been considered the invention could equally be applied to rectangular items, or indeed any item which requires aligning and then being cut.

Claims

CLAIMS 1. An automatic aligning apparatus for aligning a substantially flat article comprising ; conveyance means acting on the bottom of said article to convey said article through the apparatus, sensing means to sense when said article is in position for alignment, alignment means to align said article when said sensing means sense it is in position, at least one actuator to move said alignment means so as to align said article correctly, and control means to control said at least one actuator; characterised in that, said alignment means is mounted on a carriage, and in that said carriage moves said alignment means at a speed substantially the same as that of said article while alignment is carried out.
2. An automatic aligning apparatus according to claim I wherein said sensing means comprises a photoelectric sensor.
3. An automatic aligning apparatus according to claim 1 or claim 2 wherein said conveyance means comprises at least one belt.
4. An automatic aligning apparatus according to any preceding claim characterised in that said alignment means comprises four vertical members arranged in two pairs and each mounted so its axis is vertical with respect to the plane of said flat article; and in that said at least one actuator moves said vertical members independently in a plane normal to said axis; and wherein when said sensing means senses that an article is in position for alignment, said control means controls said at least one actuator to move said vertical members which then push said article into the desired alignment.

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5. An automatic aligning apparatus according to any preceding claim wherein said at least one actuator is a pneumatic ram.
6. An automatic aligning apparatus according to claim 4 or claim 5 wherein said vertical members have a cylindrical shape and the outer surface of said members is freely rotatable about the axis of the cylinder.
7. An automatic aligning apparatus as in claim 4,5 or 6 wherein the cylinders can be individually adjusted with respect to said actuator through a bolt on each cylinder.
8. An automatic aligning and cutting apparatus for aligning a substantially flat article and cutting said article after it has been aligned comprising: automatic alignment apparatus according any of the preceding claims to align said article, and cutting apparatus comprising holding means, acting on the top of the article and moving at the same speed as said conveyance means, which acts in collaboration with said conveyance means to feed said article past a vertical cutting blade which cuts said article ; and wherein, said conveyance means extends through both the automatic alignment apparatus and said cutting apparatus so that said article is first conveyed through the alignment section and then through the cutting section.
9. An automatic aligning and cutting apparatus according to claim 8 characterised in that said holding means is adjustable in height to allow a stack of more than one said article to be cut at a time.
10. An automatic aligning and cutting apparatus as in claim 8 or claim 9, characterised in that said article is a sandwich and said cutting blade has a cutting edge designed to minimise the spread of the filling of said sandwich during cutting.

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11. A method of aligning a substantially flat article moving along a production line comprising the steps of : determining whether said article is in position to be aligned, when it is determined that said article is in position to be aligned, moving a carrier, on which is mounted alignment means, at a speed substantially the same as that of said article, effecting the alignment of said article while said carrier is moving, and returning said carrier to said position when said alignment of said article has been carried out.
12. A method of aligning two comers of an article substantially as hereinbefore described with reference to the accompanying drawings.
13. An automatic aligning apparatus substantially as hereinbefore described with reference to the accompanying drawings.