GB2400536A

GB2400536A - Production of sandwiches

Info

Publication number: GB2400536A
Application number: GB0308571A
Authority: GB
Inventors: James Ratcliffe
Original assignee: INBIS Ltd
Current assignee: INBIS Ltd
Priority date: 2003-04-12
Filing date: 2003-04-12
Publication date: 2004-10-20
Anticipated expiration: 2023-04-12
Also published as: GB0308571D0; GB2400536B

Abstract

In an apparatus and method for the automatic production of sandwiches, slices of bread are conveyed in top and bottom streams to a loading station 1, where sandwich filling is deposited on each bottom slice 14. The slices proceed to a topping station where top slices 13 are placed on the filling on the bottom slices 14. The sandwich assemblies are aligned in an alignment station 3 prior to cutting and separation in a sandwich cutting and sandwich halves separation station 4. The cut halves are assembled with one half superposed on the next half in a clapping station 5 and subsequently packed in a skillet packing station 6.

Description

1 2400536 Apparatus For The Automatic Production Of Sandwiches The present

invention relates to apparatus for the automatic production of sandwiches.

Apparatus for the automatic production of sandwiches is already known. In one such apparatus, individual elements, which together form the finished product, are indexed between workstations at which different operations are carried out. Indexing increases cycle time, induces spillage and requires a high cost drive system. Increased complexity leads to higher maintenance and cleaning costs. The apparatus has limited flexibility and its ability to accommodate bread size tolerances is limited. In general the increased mechanical complexity requires higher safety guarding which in turn leads to higher space requirements.

According to the present invention there is provided apparatus for the automatic production of sandwiches comprising a plurality of workstations, means at each workstation for carrying out an operation on a component part of a sandwich or a sandwich and conveyor means for continuously conveying component part of a sandwich or in sandwich between workstations.

In a preferred embodiment, the workstations comprise one or more of the followings a loading station, a topping station, an alignment station, a sandwich cutting and sandwich halves separation station, a clapping station and a skillet packing station. In the loading station top and bottom slices of the sandwich are fed to the conveyor means. Advantageously, the top slice is differently oriented to the bottom slice. Preferably, the top slice has a horizontal axis arranged in the direction of travel of the conveyor means and the bottom slice has a diagonal axis arranged in the direction of travel of the conveyor means. Advantageously, the sandwich filling is supported on the bottom slice. In the topping station the top slice is raised, rotated and inserted to be on the bottom slice for the purpose the loading station advantageously comprises a rotary hand and a vacuum paddle. In the alignment station, the assembled slices are correctly aligned for the subsequent cutting operation which is carried out at the sandwich cutting and sandwich halves separation station following that latter station, at the clapping station, two triangular cut halves are placed one on top of the other to form a triangular package. To achieve this the clapping station advantageously comprises means for lifting one half relative to the other and rotating it through 180 relative to the other preferably, the means for lifting and rotating comprise a rotary hand. The skillet packing station preferably comprises means for placing the stacked triangular halves from the clapping station into a triangular skillet preferably a thermoformed skillet. The conveyor means comprises two lanes for conveying top and bottom slices respectively. Operations are preferably controlled automatically by sensors under the control of a programmable logic controller (plc).

In order that the invention may be more clearly understood, The embodiment thereof will now be described, by way of example, with reference to the accompanying drawings in which: Figure la diagrammatically shows a sequence of individual operations in the formation and packaging of a sandwich, Figure lb diagrammatically shows the orientation of sandwich parts at different workstations, Figure 2 is a plan view of apparatus for carrying out the sequence of operations of Figure la, and Figure 3 is a side elevational view of the apparatus of Figure 2 Referring to Figure la, there are six workstations in the production line at which different individual operations are carried out. These are a loading station 1, a topping station 2, an alignment station 3, a sandwich cutting and sandwich halves separation station 4, a clapping station 5 and a skillet packing station 6.

S In Figure lb, the workstations bear the same reference numerals as in Figure la. Referring to Figure lb, the product datum point identified by a black circle symbol is shown. The faces of the product through which the product is located are identified by black arrow symbols and the flow of product by a white arrow. The rise (curved faces of the bread) is indicated by the letter R. At the clapping station positions are located using sensors and the top half is rotated through 180 in a first stage operation before the top and bottom halves are aligned in a second stage operation. At the packing station the two halves together are pushed and rotated through 90 .

Referring additionally to Figures 2 and 3, a continuously running multibelted conveyor 10 is provided to convey bread slices and sandwich assemblies between workstations. The conveyor 10 is separated into two lanes 11 and 12. Each lane handles one half of the sandwich assembly. Height separation between bread or sandwich halves is achieved by elevating one of the two conveyor lanes 1 l and 12.

Access for handling the bread slices or sandwiches is from the underside of the conveyor 10 through the multi-belts.

Each of the workstations is modular and stand-alone in design. The workstation is complete with its own PLC, electrical control cabinet and pneumatic service unit. The unit will be provided with transportation wheels and a docking device to position and secure it to the conveyor arrangement.

In use product arrives at the loading station 1 at a maximum rate of 45 units/mins top and bottom bread slices orientated as follows: A prebuttered top slice 13 is disposed "square on" to the conveyor on the lane 11, with butter side upwards.

A bottom slice 14 carrying a sandwich filling is disposed with its diagonal parallel to the forward movement of the conveyor on lane 12, with filling upwards.

From the loading station 1, the top slice 13 and bottom slice 14 (with fillings) proceed to the topping station 2. At the topping station 2, the top slice of bread 13 is placed onto the filling contained on the bottom slice of bread 14. To achieve this the following actions are taken.

In lane 11 the top slice of bread 13 is transferred and elevated "square on" to the conveyor. Having reached the required separation height, the bread slice 13 travels horizontally and is held "square on" against a gate 15 protruding through the conveyor 10 multi-belts. This signals a rotary hand 16 to transfer the top slice 13 through 45 from lane l l to above lane 12 placing the slice 13 onto a vacuum paddle, 17 as illustrated diagrammatically at 18 in Figure la.

In lane 12 the bottom slice of bread 14 containing the filling travels as shown horizontally on the conveyor 10 and is held against a "V,' shaped gate l9 protruding through the conveyor to multi-belts. This signals a lift table 20 to rise between the conveyor 10 multi-belts and lift the bottom slice 14 clear ofthe conveyor belting. The gate l9 then resets below the conveyor belting.

The vacuum paddle 17 applies a vacuum to hold the top slice 13 rotates through 180 and lowers the now inverted top slice 13 into place on the filling held on the bottom slice 14 and compressed under a regulated pressure. The vacuum is released and the lift table 20 lowered allowing the topped sandwich to transfer on the conveyor 10 to the next workstation 3 in which "Optimum Cut Alignment" is effected.

In order to minimise cycle time, mechanisms in lane 1 and 2 are reset as interlocks permit throughout the topping operation. The vacuum paddle l7 is provided with vacuum porting on both faces of the paddle to eliminate the requirement to reset the paddle 180 .

In the optimum cut alignment operation the full sandwich comprising top and bottom slices 13 and 14 and filling is aligned so that a true diagonal cut can be achieved.

10In lane 12 the topped sandwich travels horizontally at 45 on the conveyor 10 belting passing beneath a vision recognition system 21 that registers the profile size of the sandwich. From this profile the true diagonal cut line is calculated and transferred to an alignment lift table 22.

The topped sandwich continues to travel horizontally on the conveyor 10 15belting until restrained "diamond shape" against a "V'' gate 23 protruding through the I conveyor 10 multi-belts. This signals an alignment lift table 22 to rise between the conveyor 10 multi-belts and lift the sandwich clear of the conveyor 10 belting. The gate 23 is lowered. Using the profile data from the vision system the allignment lift table 22 rotates the sandwich to align the true diagonal of the sandwich with the axis I of travel of the conveyor 10 and lowers the sandwich back onto the conveyor belting for transfer to the next workstation 4 where sandwich cutting and sandwich half separation is carried out.

Sandwich cutting is carried out by existing established mechanised methods.

Preferred methods are ones that can be incorporated within the conveyor 10 belting and least disturb the sandwich position during cutting that is water jet, or ultrasonic knife cutting.

Separation of the sandwich cut halves is achieved by a sideways shift in the conveyor belting, operated by a sensor 30 triggered by the sandwich as it travels on the conveyor 10.

The sandwich cut halves then proceed to the next workstation 5 which is the clapping station. In the clapping operation the two halves of the cut sandwich are brought together, one half on top of the other half to form a triangular package.

To achieve a symmetrical profile alignment of the two sandwich halves 31 and 32 (see Figure 1 a) one half of the sandwich is rotated through 180 prior to placement on the other half.

The conveyor belting transfers the cut halves 31 and 32 of the sandwich with the diagonal cut face travelling along the axis of transfer.

In lane 11 the left hand sandwich half is transferred and elevated to the required separation height then continues to travel horizontally along the conveyor belting triggering a sensor 35. This sensor 35 is linked to a timer. The signal from the sensor 35 actuates a rotary hand 36 positioned below the conveyor belting. The hand 36 rises, lifting the sandwich half clear of the conveyor belting and then rotates the top slice through 180 from lane 11 to above lane 12. As the hand 36 transfers, a stationary stripper plate comes into contact with the leading edge of the rotating sandwich half, causing the hand to slide beneath the sandwich, allowing the sandwich half to drop onto the awaiting right-hand sandwich half (see lane 12). The hand continues and is held at a parking station where it awaits the next signal allowing it to reset itself beneath the conveyor belting.

In lane 12 the right-hand sandwich half is transferred horizontally along the conveyor 10 belting triggering a sensor. This sensor 1 is linked to a timer and the signal from the sensor actuates a lift table 40 positioned below the conveyor 10 belting. The table 40 raises, lifting the sandwich half clear of the belting. The lift continues until the top surface of the sandwich half reaches a position slightly below the path of the rotating hand 36. This position is achieved by activation of a sensor set to the required height. As the left-hand sandwich half is released into position on top of the right-hand sandwich half the two halves are simultaneously moved sideways on the lift table using the stripper plate to align the two halves, the table is lowered. (The stripper plate is of a "V' shaped design, spanning both top, and bottom i halves of the sandwich. A slot is provided centrally In the "V,'profile to allow the top slice transfer hand to pass through). The stacked sandwich contacts the conveyor belting and is transferred to the next workstation 6 in which skillet packing takes place.

To minimise cycle time mechanisms in lanes 11 and 12 are reset as interlocks permit throughout the clapping operation. Also two independently controlled rotary hands are provided to minimise sandwich transfer speeds.

Skillet packing is the operation placing the two-stacked sandwich halves into a: thermoformed triangular skillet.

Skillets 50 are normally formed in rows of three. The description below relates to a single telescopic packing mechanism that extends across and deposits I sandwiches into each of the three skillets in a row. The conveyor belting transfers the stacked halves of the sandwich with the diagonal cut face travelling along the axis of transfer. A sensor detects a stacked sandwich. The signal from the sensor operates a transfer mechanism, which removes the sandwich stack sideways from the conveyor belting using a "V" shaped hand 55 onto a multi-belted conveyor running at a right angle to the main conveyor. This conveyor incorporates a second telescopic multi belted conveyer. The telescopic conveyor transfers the sandwich stack to a four station rotary turret, which can be positioned above any of the three skillet lanes. A sensor identifies the arrival of the sandwich stack and signals a "V" shaped hand to lower behind the stack and transfer the sandwich stack from the telescopic conveyor into the four station rotary turret, each station contains one fixed jaw and one gripping jaw. As the stack is positioned onto the lower fixed jaw the upper jaw is actuated gripping the sandwich stack. The transfer mechanism is reset and the turret rotated 90 above an awaiting skillet. The sandwich stack is released and falls into place in the open-ended skillet.

To minimise cycle time mechanisms are reset as interlocks permit throughout the packing operation. Resetting of the transfer mechanism incorporates a lift device for the "V" hand 55 to allow the hand to return by transferring about the stacked IS sandwich halves being transferred on the conveyor to the other packing mechanisms.

Operation of all rotary turret gripping jaws is simultaneous.

An industry standard programmable logic controller (PLC) is used to control the basic functions of the process. All sensors, variable speed drives, stepper drives, vision system and pneumatic control values are connected and controlled by the PLC.

A touchscreen Human Machine Interface (HMI) is used to operate the machine and to give the operator feedback about the operation state of the machine i.e. running/stopped alarms etc. The HEM also has an engineer mode that allows qualified personnel to change conveyor speeds and also to perform basic sequencing checks. The HMI is connected to the PLC via a serial link.

The conveyors are driven by four conveyor motors 60 to 63. Variable speed drives (VSD) are used to control the speed of the four conveyor motors. The VSD's are controlled by the PLC via the HMI.

Stepper drives are used where controlled movement of the sandwiches is required. A stepper drive is used at the optimum cut station 4 to precisely align the sandwich before the sandwich is cut. The clapping station uses three stepper drives to place the two halves of the cut sandwich precisely on top of each other prior to being packed. The packing station uses a stepper drive to rotate the assembled sandwich through precisely 90 before being dropped into the awaiting skillet. All the stepper drives are controlled by the PLC.

A vision system is used to analyse the uncut assembled sandwich prior to entering the optimum cut station 4. The system uses software sensors to calculate the optimum diagonal between the leading and trailing corners of the sandwich. This information is passed to the PLC in a Binary Coded Decimal (BCD) format. The PLC processes this information and instructs the stepper drive at the optimum cut station to rotate the sandwich the required amount to align the sandwich.

The vision system also identifies a badly assembled or an over/under sized sandwich. This information can be used to operate a reject station (not shown) to allow the sandwich to be manually reworked.

Proximity switches are used to detect the position of the pneumatic cylinders and the datum positions of the stepper drive operated mechanisms. Background suppression infrared sensors are used to detect the presence of a sandwich at the various stations. All the sensors are connected to the PLC.

It will be appreciated that the above embodiment has been described by way of example only and that many variations are possible without departing from the scope of the invention. s

Claims

1. Apparatus for the automatic production of sandwiches comprising a plurality of workstations, means at each workstation for carrying out an operation on a component part of a sandwich or a sandwich and conveyor means for continuously conveying component part of a sandwich or in sandwich between

2. Apparatus as claimed in claim 1, in which one of the workstations is a loading station in which, in operation, top and bottom slices of the sandwich are fed to the conveyor means.

3. Apparatus as claimed in claim 1, in which the loading station comprises means to orientate the top slice differently to the bottom slice.

4. Apparatus as claimed in claim 3, in which the loading station comprises means to orientate the top slice with a horizontal axis in the direction of travel of the conveyor means and the bottom slice with a diagonal axis in the direction of travel of the conveyor means.

5. Apparatus as claimed in any preceding claim, in which in operation the sandwich filling is supported on the bottom slice in the loading station.

6. Apparatus as claimed in any preceding claim, in which one of the workstations is a topping station comprising means for raising, rotating and inserting the top slice relative to the bottom slice.

7. Apparatus as claimed in any preceding claim, in which one of the workstations is an alignment station comprising means for aligning assembled slices for a subsequent cutting operation.

8. Apparatus as claimed in any preceding claim, in which one of the workstations is a sandwich cutting and sandwich halves separation station comprising means for cutting aligned assembled slices.

9. Apparatus as claimed in any preceding claim, in which one of the workstations is a clapping station comprising means for placing substantially triangular cut halves one on top of the other to form a triangular assembly.

10. Apparatus as claimed in claim 9, in which the clapping station comprises means for lifting one triangular cut half relative to the other and for rotating it relative to the other.

11. Apparatus as claimed in claim 10, in which the means for lifting and rotating comprises a rotary hand.

12. Apparatus as claimed in which the means for lifting and rotating comprise stepper motors.

13 Apparatus as claimed in any preceding claim, in which one of the workstations is a skillet packing station comprising means for placing stacked triangular halves in a triangular skillet.

14. Apparatus as claimed in claim 12, in which the packing station comprises a stepper drive to rotate assembled sandwiches through a precise angle.

15. Apparatus as claimed in any preceding claim, in which the conveyor means comprises two lanes for conveying top and bottom slices respectively.

16. Apparatus as claimed in any preceding claim, in which a programmable logic controller is provided for controlling the operation of the workstations in response to signals received from a plurality of sensors.

17. Apparatus as claimed in any preceding claim, in which conveyor motors are provided to drive the conveyor and variable speed drives are provided to control the speed of the conveyor motors.

18. Apparatus as claimed in any preceding claim, in which means are provided for analysing an uncut but assembled sandwich.

19. Apparatus as claimed in claim 18, in which the means for analysing comprises software sensors operative to calculate an optimum cut line between leading and trailing corners of the assembly.

20. Apparatus for the automatic production of sandwiches substantially as hereinbefore described with reference to the accompanying drawings.

21. A method of assembling a sandwich comprising the steps of conveying slices to a loading station, in a series of top slices and a series of bottom slices, depositing f fling on the bottom slices, placing respective top slices on corresponding bottoms slices and cutting each assembly so formed.

22. A method as claimed in claim 21, in which the cut halves of each assembly are separated and then brought together again with one half on top of the other half.

23. A method as claimed in claim 22, in which the separated halves are packed into a skillet.

24. A method for the automatic production of sandwiches substantially as hereinbefore described with reference to the accompanying drawings.