PACKAGING MACHINE AND METHOD

Abstract

A packaging machine with a platform (6) on which a container (27) can be supported and sensor (23) for detecting the presence or absence of a container (27) at a position on the platform (6). A control apparatus with a memory is configured to cause the packaging machine to perform a setup operation in which relative motion between the platform (6) and sensor (23) is caused and monitored. A parameter relating to the amount of relative motion from a starting position to a position at which the sensor output changes to reflect the presence or absence of a container (27) is stored in the memory. The control apparatus is also configured to use the stored parameter to control the machine in a packaging operation.

Claims

1. A packaging machine comprising: a platform on which a container can be supported; longitudinal transfers arms shaped to define engagement locations to engage containers on the platform in spaced apart locations along the lengths of the transfer arms; a sensor for detecting the presence or absence of a container at a position on the platform; and a control apparatus with a memory, wherein the control apparatus is configured to cause the packaging machine to perform a setup operation in which relative motion between the platform and sensor is caused and monitored and a parameter relating to the amount of relative motion from a starting position to a position at which the sensor output changes to reflect the presence or absence of a container is stored in the memory, and the control apparatus is configured to use the stored parameter to control the machine in a packaging operation.

2. A packaging machine as claimed in claim 1, wherein during the set-up operation the control apparatus is arranged to store a parameter relating to the amount of relative motion from a starting position to the point at which a container is detected by the sensor.

3. A packaging machine as claimed in either claim 1, wherein during the setup operation the control apparatus is arranged to store a parameter relating to the amount of relative motion from a position at which the sensor first detects the presence of a container to a position at which the sensor no longer detects the presence of the container.

4. A packaging machine as claimed in claim 1, wherein during the set-up operation the control apparatus is arranged to store a parameter relating to the amount of relative motion from a position at which the sensor first detects the absence of one container to a position at which the sensor first detects the presence of another container.

5. A packaging machine as claimed in claim 1, wherein during the setup operation the control apparatus is arranged to store a parameter relating to the number of containers sequentially detected by the sensor.

6. A packaging machine as claimed in claim 1, comprising a transfer arrangement operable to move to a pick up position to engage a container at a predetermined position on the platform during a packaging operation, wherein the control apparatus is arranged, during the setup operation, to cause the transfer arrangement to move to the pick-up position to enable a user to place a container on the platform at the predetermined position.

7. A packaging machine as claimed in claim 6, wherein the transfer arrangement comprises a pair of transfer arms each defining one or more bays and arranged, together, to engage on or more containers on the platform.

8. A packaging machine as claimed in any preceding claim 1, wherein the platform comprises a conveyor and the sensor is arranged to detect the presence or absence of a container at a fixed position relative to the conveyor.

9. A packaging machine as claimed in claim 8, wherein, during the setup operation, the control apparatus is arranged to monitor the distance moved by the conveyor relative to the sensor.

10. A packaging machine as claimed in claim 1, wherein during the setup operation the control apparatus is arranged to cause the conveyor to move in one direction, and during a packaging operation it causes the conveyor to move in the opposite direction.

11. A packaging machine as claimed in claim 8, wherein the conveyor is an accumulation conveyor and the control apparatus is arranged, during a packaging operation, to control motion of the conveyor to position containers on the conveyor at predetermined positions relative to one another and to the packaging machine.

12. A packaging machine as claimed in claim 8, comprising an encoder for monitoring motion of the conveyor.

13. A packaging machine as claimed in claim 1 wherein the packaging machine is a tray sealer.

14-17. (canceled)

18. A method of setting up a packaging machine having longitudinal transfers arms shaped to define engagement locations to engage containers in spaced apart locations along the lengths of the transfer arms, comprising the steps of: a. placing one or more containers in a predetermined position or positions on a platform of the machine corresponding to the engagement location(s) of the longitudinal transfer arms; b. causing and monitoring relative movement between the platform and a sensor of the machine; c. detecting the presence or absence of a container at a position on the platform using the sensor; and d. storing a parameter in a memory of the machine, the parameter relating to the amount of relative motion from a starting position to a position at which the sensor output changes to reflect the presence or absence of a container, for subsequent use in controlling the machine in a packaging operation.

19. A method as claimed in claim 18, wherein the parameter relates to the amount of relative motion from a starting position to the point at which a container is detected by the sensor.

20. A method as claimed in claim 18 wherein the parameter relates to the amount of relative motion from a position at which the sensor first detects the presence of a container to a position at which the sensor no longer detects the presence of the container.

21. A method as claimed in claim 18 wherein the parameter relates to the amount of relative motion from a position at which the sensor first detects the absence of one container to a position at which the sensor first detects the presence of another container.

22. A method as claimed in claim 18, wherein the parameter relates to the number of containers sequentially detected by the sensor.

23. A method as claimed in claim 18, wherein the machine comprises a transfer arrangement operable to move to a pick-up position to engage a container at a predetermined position on the platform during a packaging operation and comprising the steps of: causing the transfer arrangement to move to the pick-up position; and placing a container on the platform at the predetermined position, using the transfer arrangement as a guide.

24. A method as claimed in claim 18, wherein the platform comprises a conveyor which moves relative to the sensor which remains fixed relative to the remainder of the machine.

25-27. (canceled)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0037] In order that the invention may be more clearly understood one or more embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

[0038] FIG. 1 is a perspective view of a packaging machine;

[0039] FIG. 2 is a front view of the packaging machine of FIG. 1;

[0040] FIG. 3 is a schematic plan view of part of the machine of FIG. 1 in a first state; and

[0041] FIGS. 4 to 9 are corresponding views to FIG. 3 showing the machine in different sequential states during a setup operation.

[0042] In what follows the terms upper, lower, top, bottom, left and right are used to refer to the packaging machine and its components in the orientation in which it is illustrated, which is the orientation in which it is intended to be used, but should not be taken as otherwise limiting. Like reference numerals are used to denote like features throughout the drawings, which are not to scale.

[0043] Referring to the drawings, there is shown a packaging machine. The packaging machine is a tray sealer comprising a main body in the form of a cabinet 1 which houses a sealing station 2 over which is a second cabinet 3 housing switchgear and programmable control apparatus. The programmable control apparatus comprises a processor connected with a memory (or other suitable storage means) and is appropriately programmed to cause the machine to perform the functions described herein. A machine operator may operate the machine via an interface 4, such as a touch screen, provided as part of the control apparatus.

[0044] The machine is for sealing trays and comprises three servomotor driven conveyors 5, 6, 7. A first, infeed, conveyor 5 is supported on the outside left side of the cabinet 1 and extends toward a second, accumulation, conveyor 6. The accumulation conveyor 6 is also supported on the outside left side of the cabinet 1 and extends parallel to the infeed conveyor 5 from a position adjacent the end of the infeed conveyor 5 to protrude slightly into an opening in the left-hand side of the cabinet 1.

[0045] A third, outfeed, conveyor 7 extends from slightly inside an opening in the right-hand side of the cabinet 1, out of said opening and away from the cabinet 1.

[0046] The outfeed conveyor 7 extends parallel to the infeed and accumulation conveyors 5, 6. The central elongate axis of each of the three conveyors are aligned. All conveyors are substantially level and at the same height.

[0047] In operation, trays are carried toward the sealing station 2 by the infeed and accumulation conveyors 5, 6 and are carried away from the sealing station 2 by the outfeed conveyor 7.

[0048] The sealing station 2 is of a largely conventional type and is therefore not described in detail. Briefly, the sealing station 2 comprises a lower tool 8 and an upper tool 9. The lower 8 and upper tool 9 are removably fitted to the machine and are adapted to cooperate with trays to be sealed.

[0049] The lower tool 8 is supported on a platform 10 which is mounted to an actuator 11 operable to raise and lower the platform 10 and thus the lower tool 8 relative to the rest of the machine. In a lowered position, the lower tool 8 is of recesses for receiving trays to be sealed. In this exemplary embodiment, the lower tool is substantially rectangular with curved corners and comprises three, evenly spaced, substantially rectangular, recesses formed in its upper surface. The central elongate axis of the lower tool 8 is aligned with that of each of the three conveyors 5, 6, 7.

[0050] The upper tool 9 is positioned above the lower tool 8 in a fixed position. The upper tool 9 is heated and in use a sealing film (not shown) extends between the two tools adjacent the upper tool 9.

[0051] The machine comprises a pair of transfer arms 12 positioned above and at opposite sides respectively of the lower tool 8 (when in a lowered position). Each arm is elongate with a rectangular cross section. The arms 12 are level and extend parallel to the long sides of the lower tool 8 (and consequently, parallel to the three conveyors 5, 6, 7) and substantially parallel to the upper surface of the lower tool. The transfer arms 12 are mirror opposites of each other.

[0052] The opposed, inner faces of the arms are shaped to engage with multiple spaced apart trays. Each arm comprises six fingers 13 provided in two groups of three separated by a central portion 14 which projects in the same direction as the fingers 13. The three fingers in each group are evenly spaced and the width of the central portion is approximately equal to the separation between adjacent fingers. The fingers 13 and central portions 14 of each arm together define six bays 15. The lower edge of each bay comprises a lip projecting diagonally outward so that when the arms close around a tray, the tray is lifted slightly from the surface on which it is supported.

[0053] A central connecting bracket 16 projects from the outer face of the arm opposite the central portion 14. A first substantially vertical support member 17 connects at one end to the bracket 16 of one arm and is movably mounted at the other end to one of a pair of parallel rails 18. A second substantially vertical support member 19 connects to the bracket 20 of the other arm and is movably mounted to the other rail. The rails 18 are vertically positioned above the upper tool 9 and extend horizontally and parallel to the long sides of the lower tool 8.

[0054] The rails 18 are movably mounted on transverse, horizontal supports and a servomotor controls the separation between the rails 18. The arms are movable away from each other to an open state in which the minimum separation between the arms is greater than the tray width so that a tray may travel along the conveyors 5, 6, 7 between the transfer arms 12, and also movable towards each other to a closed state in which a tray positioned between the transfer arms 12 is engaged by the arms.

[0055] Each support member 17, 19 is driven along the rails 18 by a servomotor provided at its rail-mounted end. The arms 12 are movable from a pick-up position, wherein the three bays defined at the infeed end of the arms (infeed bays) 21 are positioned above the accumulation conveyor 6 and the three bays at the opposite ends of the arms (outfeed bays) 22 are positioned above, and aligned with, the recesses in the lower tool 8, to a set-down position, wherein the infeed bays 21 are positioned above, and aligned with, the recesses in the lower tool 8 and the outfeed bays 22 are positioned above the outfeed conveyor 7.

[0056] The control apparatus controls the operation of all servomotors in the packaging machine. Each servomotor comprises an encoder, which outputs a pulsed signal to the control apparatus representative of the motion of the servomotor. The control apparatus monitors the motion of the servomotor by counting pulses output by the encoder, and uses this information to determine the position, speed and like information relating to the motion of each servomotor. For the servomotors used to drive the conveyors 5, 6, 7, the control apparatus uses the encoder information to determine the distance travelled by the conveyor.

[0057] A photoelectric, break-beam sensor 23 is provided at the end of the infeed conveyor 5 closest the accumulation conveyor 6. The sensor 23 comprises an emitter which emits a beam 25 (typically of visible or infra-red light) and a receiver (not shown) which detects the beam 25. The beam 25 extends perpendicularly across the conveyor path. The break-beam sensor 23 is connected to the control apparatus and is arranged to output a first signal thereto when the beam 25 is detected by the receiver (indicating the absence of a tray in the line-of-sight of the sensor 23) and a second signal when the beam 25 is “broken”, and is therefore not detected by the receiver (indicating the presence of a tray in the line-of-sight of the sensor 23). The first signal may be an output from the sensor and the second signal the absence of an output. The control apparatus is configured to count the number of trays which pass the sensor 23.

[0058] As with conventional tray sealers, the control apparatus causes the infeed and accumulation conveyors 5, 6 to operate depending on three positioning parameters, pitch, position and length, and the number of containers.

[0059] Where the control apparatus differs from prior apparatus is that it is arranged to cause the machine to perform a setup operation to determine the positioning parameters and number of trays using information provided by the accumulation conveyor servomotor encoder and the photoelectric sensor 23. Setup of the machine takes place as follows: [0060] a) A machine operator initiates the setup operation from the interface 4. If the setup operation is part of the initialisation of the machine, it is envisioned that the machine will be free from trays. However, if the setup operation is part of a recalibration of the machine, it is important to ensure that there are no trays on the infeed and accumulation conveyors 5, 6. So, initiating the setup operation may involve a final operation of the machine to transfer any trays the machine to the outfeed conveyor 7, resulting in the transfer arms 12 being in the set down position as shown in FIG. 3. [0061] b) After any operation to clear trays from the machine, the transfer arms 12 are moved to the pick-up position and closed state, as shown in FIG. 4. The machine then prompts the user to place trays into the infeed bays 21 of the transfer arms 12. The machine operator opens the protective guard 26 covering the accumulation conveyor 6 and places a tray into each infeed bay, as shown in

[0062] FIG. 5. The sample trays 27 are the same size and shape as the trays to be sealed, and although they do not contain any foodstuff, a weight 28 may be placed in each sample tray so that they behave like a tray containing foodstuff. [0063] c) The machine operator then informs the control apparatus, via the interface 4, that the sample trays 27 have been placed into the any movement along the rails 18, the transfer arms 12 are moved slowly into the open state (that is, slower that the transfer arms are opened during a packaging operation) to leave the sample trays 27 in the pick-up position on the accumulation conveyor 6, as shown in FIG. 6.

[0064] The machine then automatically determines the positioning parameters, and the number of trays, as follows: [0065] a) The infeed and accumulation conveyors 5, 6 are operated in reverse at substantially the same speed as each other to carry the trays 27 away from the sealing station. During this step, the conveyors are operated to run slowly (that is, slower that the conveyors operate during a packaging operation) to ensure that the trays do not move from their positions. The infeed and accumulation encoders provide information to the control apparatus representative of the rotation of each servomotor and thus movement of the conveyors 5, 6. [0066] b) The control apparatus records movement of the accumulation conveyor 6 and, when the rearmost tray (that is, the tray farthest the sealing station) breaks the beam 25 of the photoelectric sensor 23, as shown in FIG. 7, the control apparatus stores the distance moved by the accumulation conveyor from the start of the movement in memory as the position positioning parameter. The control apparatus also records that one tray has passed the sensor. [0067] c) When the beam 25 is received again by the receiver 24 following 23, as shown in FIG. 8, the control apparatus stores the distance moved by the conveyor 6 since the beam was broken as the length positioning parameter. [0068] d) When the second rearmost tray breaks the beam 25 of the photoelectric sensor 23, as shown in FIG. 9, the control apparatus stores the distance moved since the beam 25 was restored as the pitch positioning parameter. The control apparatus also records that two trays have passed the sensor 23. [0069] e) The control apparatus continues to drive the conveyor 6 until it has moved a distance approximately equal to the length of the conveyor and increases the conveyor count for each further container detected thereby to count the total number of trays and stores this value.

[0070] The three positioning parameters are thereby determined with high accuracy and are stored in memory. The number of trays is also determined, which indicates the number of infeed bays 21. The positioning parameters and number of trays parameter can then be used in normal operation of the packaging machine to position trays correctly on the accumulation conveyor 6 so that moving the transfer arms 12 to the pick-up position and closing the arms allows the trays to be received into the bays.

[0071] Optionally, the machine may be configured so that one sample tray need not be placed into each infeed bay 21. In this configuration, the machine may prompt the machine operator to inform the control apparatus, via the interface 4, of the number of transfer arm bays 21 and also in which bays sample trays 27 are placed.

[0072] Where a first sample tray is placed in the rearmost infeed bay, and a second sample tray is placed in a second, non-consecutive, infeed bay, the position and length parameters may be determined as described above, and the pitch positioning parameter may be calculated using knowledge of the bay in which the second sample tray is placed. Where the first sample tray is not placed in the rearmost infeed bay, the position parameter may still be determined using knowledge of the bay in which the first sample tray is placed.

[0073] Further optionally, the machine may be configured so that only one item of the information is required to be inputted by the machine operator. In this regard, a first sample tray is placed in the rear most infeed bay and a second sample tray is placed in the next adjacent infeed bay. With this arrangement, the only information that the operator need input is the number of infeed bays. The system can determine the pitch using the first and second sample trays and with the knowledge of the number of sample bays the position and length parameters may also be determined. It will be appreciated that a minimal amount of information need be provided to the control apparatus while resulting in precise and accurate configuring of the packaging machinery.

[0074] The one or more embodiments are described above by way of example only. Many variations are possible without departing from the scope of protection afforded by the appended claims.