GB2226003A - Packaging equipment - Google Patents

Abstract

An adhesive joint checking device, which in normal operation is intended to be preceded by or form part of packaging equipment which delivers to the device a succession of roll-wrapped packages, for example, cylindrical packages, whose wrapping is lap-joined along the length of the package; the device comprising means, for example, two contra-rotatable rollers 2 which support the package and rotate it about its longitudinal axis; a wrapping-edge-displacing member comprising at least one protuberance 13 which is so mounted in relation to the rollers or other package-support means that the protuberance or at least one of the protuberances if there are more than one, engages the package at an appropriate position along the adhesive joint, when the package is rotated, in such a way that if the adhesive joint between the over- lapping portions of she packaging is defective, the protuberance will tend to displace the over-lapping portion 15 of the package away from the body of the package; and a detector comprising e.g. photocells in sufficiently close proximity to the displacing member that it generates a reject signal when the amount of thus displaced package material fails to satisfy predetermined requirements. An air jet may assist in lifting said portion 15. The device is disposed along a walking beam type conveyor comprising fixed and moving toothed racks. A first test facilitating comprising a reciprocable pad for detecting incompletely filled packs is followed by package and hot and cold shaping presses, end fold checking station comprising a photocell unit, the adhesive joint checking station, and a weighing station. <IMAGE>

Description

PACKAGING EQUIPMENT Background to the Invention The invention relates to packaging equipment and, in particular, to the provision of testing facilities in such equipment.

In many cases, the packaging of an item includes a foil or paper wrapper which embraces the item, and has overlapping portions attached to one another along an adhesive joint. The adhesive joint of such packaging commonly has to satisfy requirements relating to its effectiveness.

The invention is more specifically concerend with checking whether or not such requirements are met.

According to the invention, there is provided packaging equipment which includes transfer means for feeding packaged items to adhesive joint checking means at which the effectiveness of an adhesive joint in the packaging of each packaged item is checked and, in the event of a faulty joint being identified, a reject signal is generated, the adhesive joint checking means comprising a pair of rollers between which, in use, a cylindrical packaged item is supported, the rollers being so rotated as to effect rotation of the package; at least one displacing member; and means detecting the displacement of the overlapping portions of the package away from the main body of the package, the displacing member having one or more protruberances and being so mounted relative to the rollers that the or at least one of protruberances engages, in use, the package in such a way that, if the adhesive joint between the overlapping portions of the packaging is defective, the protruberance will displace the overlapping portion of the package away from the body of the package.

The transfer means may be such that feeding of the packaged items is effected in discrete steps and that a dwell is provided between successive steps, the length of a dwell being such that a checking operation can be performed by the adhesive joint checking means during one or more dwell periods.

In this case, the transfer means may comprise a walking beam unit, the walking beam unit comprising a moveable toothed rack which co-operates with stationery toothed rack so that, during each advancing movement of the moveable rack, a packaged item is transferred from one trough of the fixed toothed rack to another trough of the fixed tooth rack, the dwell between successive steps of advancing movement of a packaged item being provided by return movement of the moveable rack which is driven by a suitable eccentric drive mechanism.

Preferably the displacing member comprises a cylinder rotatably mounted generally above the rollers and having one or more protruberances, the or each protruberance being formed as a spike projecting radially from the surface of the cylinder.

There are preferably provided two such cylinders which are so positioned that, in use, the protruberances engage the pack at the respective end regions of the adhesive joint.

The means detecting the displacement of the overlapping portion of a package may be provided by a checking station situated downstream of the displacing member, and comprising a pair of rollers between which, in use, a cylindrical packaged item is supported, the rollers being rotated so as to effect rotation of the cylindrical packaged item; and a photocell unit which projects a beam towards the packaged item at a position such that, if the overlap at the joint has been displaced away from the body of the package, the light beam of the photocell unit will be interrupted, this interruption will be detected by the photocell unit which consequently generates a reject signal.

Brief Description of the Drawings The invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic side view of apparatus providing adhesive joint checking means according to the invention and Figure 2 is a plan view of the apparatus shown in figure 1.

Description of an Embodiment In this embodiment, the invention provides one of a number of testing facilities present on a walking beam inspection unit for a packaging machine for packaging wrapped boiled sweets or mints into packets of, say ten or twelve mints, the packaging which is placed around the mints after they have been arranged in a row comprising a foil wrapper and, around this, a paper wrapper which is printed with advertising and other material, the paper wrapper being in the form of a rectangular sheet which is folded into cylindrical form around the pack of mints and the overlapping edges of which are bonded together using an adhesive.

The walking beam inspection unit comprises two toothed racks each of which comprises two parallel spaced rows of teeth. The first of the two racks is a stationary rack and the two rows of teeth of this stationary rack are spaced apart, the tooth form of the one rack being identical with that of the other rack and with the teeth in the one rack in register with those of the other rack. Each tooth has two equally and oppositely inclined faces and the dimensions of the troughs between the teeth are such that when a pack of mints is placed in aligned troughs of the two rows of teeth, it will touch the side faces of the teeth at a position spaced from the base of the trough, the precise point of contact being dependent on the diameter of the pack of mints in relation to the spacing between adjacent teeth.

The two rows of teeth forming the first of fixed rack are disposed one on each side of two further rows of teeth of a second toothed rack, the second toothed rack being moveable and the teeth of the two rows of the second toothed rack being identical to the teeth of the two rows of the first or fixed toothed rack. The two rows of teeth of the movable rack are spaced apart one from another with the spacing between the two rows of teeth of the movable rack an order of magnitude greater than the spacing between one of the rows of teeth of the movable rack and the adjacent row of teeth of the fixed rack.

The movable rack is connected to an eccentric drive mechanism whereby any point on the movable rack Is caused to move in a generally circular path. The diameter of this circular path corresponds to the pitch of the teeth of the toothed racks and the arrangement is such that, during one cycle of movement of the movable rack, the movable rack moves upwardly from a position in which a tooth on the movable rack is in register with a corresponding tooth of the fixed rack and then, as the circular movement continues and a half revolution is effected, the tooth on the movable rack moves into a position in register with the next tooth of the fixed rack. With continued downward movement of the movable rack, the movable rack continues Its cycle of movement to return it to its original position. The radius of movement of any point on the movable rack Is such that, during movement of the movable rack through its first 1800 of movement from its original position as described above, a cylindrical pack of mints located in one tooth trough of the fixed rack will be moved into the next tooth trough of the fixed rack.

The motion is thus such that, during the first 1800 of rotation, the teeth of the movable rack effectively pick up and transfer all the packets of mints on the fixed rack by one step.

During the second 1800 of movement, the movable rack moves downwardly clear of the packs of mints and of the fixed rack and returns to Its initial position ready for the next cycle of operations.

If, therefore, one considers the movement of a pack of mints, it is moved during the first 900 cycle of operations upwardly out of one trough, during the next 90 of rotation, it is moved downwardly into the next tooth trough. During the following 180 of rotation it remains in the position in which it has been placed, i.e there Is a dwell in the advancing movement of the packs of sweets with the length of the dwell time equal to the length of the feed time.

A number of stations are located along the length of the inspection unit afforded by the fixed and moveable racks.

Two such stations form the adhesive joint checking means according to the invention.

Referring to figure 1, the adhesive joint checking means includes a first station (generally referenced 1) at which there are provided two parallel rotating rollers 2. The rollers 2 are arranged for rotation parallel to one another, and extend at right angles to the path of movement of the packets of mints, each of which is advanced in the direction indicated by the arrow A by one cycle of the walking beam unit.

The rollers 2 are arranged to be driven in unison by a belt drive system (not shown), and are disposed between the two rows of teeth of the moveable toothed rack. The rollers 2 are positioned so that their upper surfaces are disposed at substantially the same horizontal level as the tooth tips of the teeth of the fixed rack so that, when a packet of mints 3 is at the first station, it is supported between the rollers 2, the elongate axis of the packet 3 being substantially parallel to those of the rollers 2. The rollers 2 are arranged to rotate the packet of mints resting between them in a clockwise direction as seen from figure 1 A displacing member 4 is mounted above the rollers 2 on a frame member 5, and includes a shaft 6 fixed to the frame member 5.The shaft 6 extends in the direction parallel to the elongate axis of the rollers 2, and carries a pair of trailing arms 7, each of which is pivotally mounted on an end region of the shaft 6.

A spring (not shown) acts between the shaft 6 and the arms 7 to exert a downward biasing force on the arms 7.

A stop 8 is mounted on the shaft 6, and serves to limit the downward pivotal movement of the arms 7 by engaging a screw threaded member 9 mounted in a correspondingly screw threaded hole in a bar 10 running between the arms 7.

The limit of the downward pivotal movement of the arms 7 can thus be adjusted by screwing or unscrewing the member 9 in the bar 10.

A pair of cylinders 11 are rotatably mounted on a shaft 12 running between the end regions of the arms 7 opposite the shaft 6. Eight equally circumferentially spaced spikes (for example 13) radiate from the surface of each cylinder 11. Each spike 13 is mounted on its respective cylinder 11 in a position which is offset from the centre of the cylinder. As a result, the lateral position of the spike may be altered by removing the shaft 12 from the arms 7, and reversing the cylinders 11 on the shaft 12 so that the end of each cylinder 11 previously nearest the corresponding end of the shaft 12 is now the end furthest frona the end of the shaft 12.

An overhead roller 13 is situated between the cylinders 11, and is rotatably mounted on the shaft 12, the shaft 12 passing through a central bore 14 of the roller 13. The diameter of the bore 14 is significantly greater than that of the shaft 12, enabling the roller 13 to be raised or lowered to a limited extent with respect to the shaft 12.

With no packets of mints resting between the rollers 2, the screw threaded member 9 enagages the stop 8, and the cylinders 11 thus occupy their lower most position. As a packet of mints (for example 3) is advanced into a position in which it rests on the rollers 2, the arms 7 pivot on the shaft 6 in such a way that the cylinders 11 (and the roller 13) are raised to accomodate the packet 3.

When the packet 3 is resting between the rollers 2, the cylinders 11 and the roller 13 bear against the packet 3.

The packet 3 is then rotated in a clockwise direction by the rollers 2, causing the cylinders 11 to be rotated in an anti-clockwise direction until one of the spikes 13 (for example 13a) engages the packet 3. The position of the overlapping portion of the wrapper of the packet 3 is such that, as the spike 13a travels over the overlapping portion of the wrapper, it travels over first the upper overlapping edge and then the lower overlapping edge of the wrapper.

If the adhesive joint is defective, the spike 13a will urge the upper edge of the overlapping portion away from the rest of the packet to form a flap 15. As this happens, the force exerted on the spike 13a may so pivot the arm 7 that the cylinders 11 move slightly away from the packet 3. However, should this happen, the enlarged bore 14 of the roller 13 enables it to keep exerting its full weight on the packet 3. The purpose of the roller 13 is to prevent the racket 3 from being dislodged from the rollers 2 by this process.

Additionally, a jet of compressed air may be caused to impinge upon the surface of the packet 3 in such a way as to assist the lifting of the flap 15 away from the packet 3 . The air jet may, for example, be directed parallel to the arrow B.

The positioning of the spikes 13 depends on the requirements that the adhesive joint has to satisfy; commonly, the adhesive joint must extend to within 20 millimetres of each end region of the overlapping portion of the wrapper.

In this case, the position of the spikes 13 is accordingly chosen so that, in use, two of the spikes engage the wrapper at least 20 millimetres from its ends, i.e the edges of the wrapper perpendicular to the overlapping edges.

The packet 3 is then advanced to a second station 16 which is situated downstream of the first station 1, and which provides the means detecting the displacement of the overlapping part of the package, the flap 15. The second station 16 comprises two rollers 17 which are similar in both form and function to the rollers 2.

Two overhead wheels 18 are rotatably mounted above the rollers 17 on an arm 19 which is, in turn, pivotally mounted at a pivot 20 on a projection 21 from the frame member 5. The arm 19 incorporates a projection beyond the pivot 20 which, when no packet is present on the roller 17, bears against a screw threaded stop 22 on a projection 23 from the frame member 5 to limit the downward pivotal movement of the arm 19. This limit can be adjusted by screwing or unscrewing the stop 22 in the projection 23.

Two photocells (not shown) are positioned one at either end region of the rollers 17, and are so positioned as to project, in use, a beam of light onto the wrapper of a packet (for example 3a) resting on the rollers 17. The arrangement is such that, if the packet 3a includes a flap such as the flap 15, the beam from one of the photocell units will be interrupted, this interruption will be detected and a reject signal consequently generated.

As a packet is placed on the rollers, the wheels 18 move up on the arm 19 to accommodate the packet (for example the packet 3a). The packet is then rotated by the rollers through about 2 revolutions so that the photocells scan the overlapping portions of the wrapper. The purpose of the wheels 18 is to inhibit any pitching or yawing motion that the packet may exhibit as it is rotated on the rollers 17.

If a flap such as the flap 15 is detected, a reject signal will be generated by at least one of the photocells, and will be used to eject the package as it passes a reject station the operation of which will be described below.

The rest of the inspection unit will now be described.

It is to be appreciated that the other facilities to be provided along the length of the inspection unit will vary depending upon the nature of the confectionery and the particular manner in which it has been wrapped and packaged. The other stations will, however, each be arranged to perform a partiuclar function on each of the packages of sweets in succession during the dwell times corresponding to the second part of the cycle of movement of the moveable ram.

The packages of mints are fed onto the input end of the inspection unit with the method of feeding such that, at the input end of the unit each gap between adjacent teeth is occupied by a package of mints. The first test facility which is provided may be a loose pack detector which comprises a pad mounted on a reciprocable piston with the pad arranged to engage a package of mints approximately centrally thereof . The arrangement is such that, if the package Is a complete package of mints, the path of travel of the pad will be interrupted at predetermined position and the pad will then be retracted. If, however, the resistance to movement of the pad is reduced as a result of, for example, loose packaging of the mints, any degree of over-travel of the pad will result in the transmission of a reject signal.This reject signal is transmitted to a pneumatic control mechanism via a delay mechanism, the pneumatic control mechanism being connected to a nozzle located at a reject station at a position spaced three steps along the inspection unit.

When, therefore, the incorrectly packaged pack of mints which has been responsible for the reject signal reaches the reject station, an air blast is directed horizontally across the path of travel of the packs of mints to displace the pack of mints at the reject station. The nozzle provides a confined blast of air such that it is only the pack of mints at the reject station which is affected by the air blast. At the reject station, a cradle is provided to receive the packs of mints in turn and to channel the air blast. It is convenient to have a number of teeth between the test station and the reject station.

If desired, however, the reject station may immediately follow the test station.

At a position downstream from the loosepack detector and its associated reject station, the packets of mints pass through a series of end press units which shape the ends of the packets of mints. Each end press unit comprises a pair of reciprocable forming dies, one disposed on each side of the path of travel of the mints, the packets of mints being arranged so that their longitudinal axes are at right angles to the path of travel and so that their ends are accessible for forming operations.There are conveniently three pairs of heated end press units, i.e. end press units which have heated dies which act on the ends of the packets of mints to form them to the desired shape, the three heated end press units being followed by a cold press unit, i.e. an end press unit the forming dies of which are cold, the cold forming dies of this final end press unit performing a final shaping of the ends of the packets of mints. The individual end press units are preferably spaced along the path of travel of the packets of mints with a spacing between adjacent units equal to twice the toothed pitch of each toothed rack.

If, therefore, one considers the travel of a packet of mints, it reaches the first end press unit position at which its ends are acted upon by the heated dies which move in as soon as the packet of mints reaches its dwell position and then, immediately before the next advancing movement of the packets of mints, the heated dies are withdrawn. The packet of mints is then advanced by a distance corresponding to one tooth pitch. No operation is performed on the packet of mints during this dwell stage and then the packet of mints, in the next cycle of operation of the moving rack, is advanced to the position of the next heated end press unit. This cycle of operations is repeated for each of the heated end press units and for the cold end press unit.After the packets of mints have passed through the various end press unit stations, repeated advancing movement of the packets of mints brings them to the first of a series of three testing positions, the space between the first of the three testing stations and the cold end press unit corresponding to three tooth pitches with the spacing between adjacent test stations also corresponding to three tooth pitches.

The first of the three testing stations is a reflective foil check ing station at which a check is made to determine whether the reflective foil at the ends of each package of mints has been folded correctly. The reflective foil checking station comprises two units, one at each side of the path of travel of the mints and each unit comprises a light source and a photocell unit. The light source is arranged to direct a beam of light onto a position on the end face of the package of mints substantially centrally thereof so as to be reflected onto the photocell. If the position at which the reflected light beam strikes the photocell unit corresponds to correctly folded foil then an accept signal is generated.If, however, the reflected light beam fails to impinge on the correct pos tion of the photocell unit, a reject signal is generated. Since light beam and photocell units are disposed at each side of the path of travel of the packets of mints so as to inspect both ends of each packet of means, and it is desired that a packet of mints should be rejected if the reflective foil at either end has been incorrectly folded, the reject signals from the two photocell units are transmitted to an OR gate such that, if either end of the packet of mints is faulty, a reject signal is obtained from the output of the OR gate. This reject output signal is transmitted to a control unit which controls operation of a reject station at a position further down the path of travel of the packets of mints. The second station is the adhesive joint checking means already described.

The third of the three testing stations is a weighing station at which each packet of mints is weighed. The weighing station includes a weigh head which is formed with an upwardly open V-section channel to receive a packet of mints, the tops of the sidewalls of this V-section channel being at a level just above the tips of the teeth of the fixed rack. The sides of the V-section channel are positioned so that, when a packet of mints is at the weighing station, it is supported by said channel sidewalls just clear of the sidewalls of the teeth of the fixed rack. The weigh head is connected to a load cell which transmits an output signal determined by the weight of a packet of mints and this output signal is transmitted to a comparitor unit at which a comparison is effected between the output signal determined by the weight of a packet of mints being tested and a standard reference value. If the weight of a packet of mints being tested varies from the reference weight by more than a predetermined amount, a reject signal is generated which is transmitted to the control means for the reject station as described below.

During the course of a day, there will be a degree of variation in the weights of a complete packet of mints, such variation arising from, for example, variations in temperature and other variables. In order to compensate for such variation, the reference value with which the weight of a packet of mints under test is compared is not a constant value but is continuously updated. The reference value may be based on, for example, the average weight of the ten previous packets of mints which were acceptable.

At the reject station there is a support tray having a curvate supporting surface to receive a packet of mints and to support it clear of the sidewalls of the teeth of the fixed rack.

This support tray is disposed between the two rows of teeth of the movable rack. It has a longitudinal axis which Is disposed at right angles to the path of movement of the packets of mints and, at its leading and trailing edges, it is substantially flush with the tips of the teeth of the fixed rack.

When a packet of mints is supported on the curvate support surface at the reject station, its axis Is disposed substantially in line with the axis of a pneumatic nozzle. The pneumatic nozzle is connected to a source of compressed air and, on operation, is arranged to direct a blast of air across the path of movement of the packets of mints and to displace a packet of mints supported at the reject station and to direct it to a reject chute.

The control of operation of the pneumatic nozzle is effected by a control system which is arranged to receive reject signals from any one of the three testing stations. A stepping control is initiated on receipt of a reject signal and this steps forward for each advancing step of the movable rack so that, when a packet of mints responsible for generation of a reject signal reaches the reject station, the control means at the reject station will cause a controlled blast of air to be directed across the inspection unit to displace the reject packet of mints.

One of the things which can happen, particularly at the commencement of a shift, with incomplete bonding of paper or foil wrapping materials because of, for example, hardening of the adhesive if the apparatus has been allowed to stand for an extended period. A facility to test for packages of sweets which have not been effectively wrapped is accordingly provided at the commencement of the walking beam inspection unit.

When a package of sweets is advanced during appropriate movement of the moveable rack, the package of sweets is supported at two spaced positions and, if there has been any failure of the adhesive, the package will sag or bow between the two positions at which it is supported. A sensor is accordingly provided and is so positioned that, when a correctly wrapped package of sweets is lifted, the sensor is displaced through firm engagement with the package of sweets and an accept signal is generated. If, on the other hand, the sensor has not been operated by the time that a predetermined position in the cycle of operations of the apparatus is reached, a reject signal will be generated. The generation of the reject signal will result in an operation being carried out designed to remove an incorrectly or incompletely wrapped package of sweets. The reject operation may be carried out by means of a piston and cylinder mechanism which is positioned above the walking beam inspection unit, the pistion carrying a plate which is arranged to move downwardly between the rows of teeth of the moveable rack so as to ensure that any package of sweets is push downwardly between the two rows of teeth of the moveable rack for passage to a reject shoot. The sensor which senses the presence of a correctly wrapped package of sweets may be mounted on the piston of the piston and cylinder mechanism so that a compact unit may be provided. Alternatively, the piston and cylinder mechanism may be located at a position one tooth downstream of the sensor.

Claims (1)

1. CLAIMS:

   1. An adhesive joint checking device, which in normal operation is intended to be preceded by or form part of packaging equipment which delivers to the device a succession of roll-wrapped packages, for example, cylindrical packages, whose wrapping is lap-joined along the length of the package; the device comprising means, for example, two contra-rotatable rollers which support the package and rotate it about its longitudinal axis; a wrapping-edge-displacing member comprising at least one protruberance which is so mounted in relation to the rollers or other package-support means that the protruberance or at least one of the protruberances if there are more than one, engages the package at an appropriate position along the adhesive joint, when the package is rotated, in such a way that if the adhesive joint between the over-lapping portions of the packaging is defective, the protruberance will tend to displace the over-lapping portion of the package away from the body of the package; and a detector in sufficiently close proximity to the displacing member that it generates a reject signal when the amount of thus displaced package material fails to satisfy predetermined requirements.