GB1566057A - Labelling machines - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO LABELLING MACHINES (71) We, MORGAN FAIREST LIMITED.

a British Company of Fairway Works.

Carlisle Street, Sheffield S4 7LP, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be perfonned, to be particularly described in and by the following statement : This invention relates to labelling machines, and has for its object the provision of a labelling machine incorporating means for melting heat seal adhesives.

Heat seal adhesives are of two types : - (1) instantaneous heat seal adhesives which, on heating, change from a rigid plastic state, through a soft flexible stage, to become an adhesive melt, and which, on removal of the heat source, rapidly cool and solidify; and (2) delayed action heat seal adhesives, which also soften and melt on heating, but which are formulated to remain molten for a longer time when the heat source is removed, this delayed action being achieved by incorporating in a thermoplastic coating plasticisers which melt and dissolve the thermoplastic to form the adhesive.

Both these types of adhesives are used on labels and are normally heated by means of hot plates or hot air, but these methods have several disadvantages: (A) they are inefficient in that only a small proportion of the heat is used to melt the adhesive; (B) the excess heat tends to heat up the machinery and the articles being labelled; and Q the label heating time is long, due to inefficient heat transfer to the adhesive.

The present invention overcomes these disadvantages by using focussed infra-red radiation to melt the adhesive. Thus, according to the present invention, a labelling machine comprises a heater having a reflector with an elliptical section, and an infra-red radiant element having its axis disposed at one focal line of the elliptical reflector, a magazine for labels bearing heat seal adhesive and transfer means for transferring individual labels from the magazine to articles to be labelled via the heater with each label passing through the second focal line of the elliptical reflector and wth the adhesive toward the heater element.

The speed with which the labels are passed through the second focal line depends upon the power dissipation in the heater element, the efficiency of the reflector, the wave length range of the emitted energy, and the properties of the adhesive - that Is, the heat required to melt the adhesive and raise its temperature to the required value and the absorption characteristics of the adhesive for the given wave length range, It will be evident that in order for the labels to pass through the second focal line of the elliptical reflector the elliptical refelector cannot be a complete ellipse, but by preferably extending the elliptical reflector to a plane substantially at the sec- ond focal line through which the labels pass (which plane is preferably perpendicular to the major axis of the ellipse), or by using additional flat reflectors beyond the extent of a more limited part-elliptical reflector, a very large percentage of the heat generated can be focussed on to the adhesive, with a very high energy density at the second focal line so that short heating times can be achieved. By providing flat reflectors (which with the elliptical reflector are preferably polished or plated) at the ends of the element and screens defining an aperture around the second focal line of the elliptical reflector, stray emission can be limited to prevent heating up of machinery and articles being labelled.

The elliptical reflector is preferably pro vided with passages for cooling medium, e.g. recirculating water, and the flat end reflectors may also be provided with passages for cooling medium. The screens defining an aperture around the second focal line of the elliptical reflector are preferably detachably secured to the reflector, so as to enable the screens to be changed to change the size of the aperture (particularly in the direction parallel to the second focal line) to suit a change in the size of labels.

A silicon carbide resistance heater element can be operated at 15000C so that the machine can be operated at high speed.

However, the machine is also required to operate at low and medium speeds and, therefore, is preferably provided with a feedback control system for changing the temperature of the element as a function of tfie labelling speed. An adhesive condition sensor is preferably disposed adjacent the heater to detect that adhesive on a label has been melted by passage past the heater, which sensor may consist of a light emitting diode sensing the reflectivity of the adhesive.The adhesive condition sensor is preferably inter-linked to a label inlet sensor, so that the adhesive condition sensor only functions when a label is present on the rotary transfer means, and the label inlet sensor is preferably inter-linked to a counter switch for putting the machine into a "stand-by" mode, if for for example - more than three successive labels are absent from the rotary transfer means, as could result from an empty label magazine, the "stand-by" maintained at the required temperature, mode being one in which the heater is but a movable shutter is preferably provided to close the aperture defined by the heater screens, so that overheating of the transfer means does not occur.One or more heat sensors may be incorporated in the reflector or reflectors and linked to the feedback control system so that, if the heater fails or the temperature of the heater element exceeds a set amount, the machine is switched off.

In the particular application of the invention to the labelling of bottles, the labelling machine preferably also comprises a conveyor for feeding bottles past the rotary transfer means, and spacing and timing means arranging for bottles to be brought to the transfer means in phase with labels carried by the transfer means; and the feedback control system preferably includes a movable stop to prevent bottles entering the machine during the "stand-by" mode, which will also have to be achieved when the machine is first switched on and the heater has to equilibrate at the required temperature before labelling can commence. A bottle detector is preferably provided in the feedback control system to cause the absence of a succession of bottles (e.g. three or more) at the spacing and timing means to put the machine into "stand-by" mode.The label magazine is preferably provided with means (e.g., an air cylinder or solenoid) for moving it from an operative to an inoperative position when a bottle is not detected by the bottle detector after withdrawal of the movable bottle stop, so that a label cannot be carried by the transfer means (and past the heater) if there will be no bottle to receive it. The label magazine is preferably otherwise substantially fixed in position and high-speed-rotary pick-out means (e.g., of any known type) is provided to remove labels one at a time from the magazine and carry them to the transfer means.

Finally, a hold-up detector (e.g., a pressure sensitive switch) is preferably provided beside the conveyor leading away from the rotary transfer means, so that if there is a hold up in the discharge of labelled bottles from the machine then the machine is put into the "stand-by" mode.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic plan of a bottle labelling machine in accordance with the invention; Figure 2 is an enlarged part-sectional plan of the transfer means and pick-out means appearing in Figure 1; Figure 3 is an enlarged part-sectional plan of the heater appearing in Figure 1; and Figure 4 is a vertical section substantially on the line IV-IV of Figure 3.

In Figure 1 bottles 10 are carried by a slat conveyor 11 through the labelling machine, and the bottles are spaced and timed by a feed-worm 12 for rolling contact with label-holding pads 13 of rotary transfer means 14, which receives labels 15 removed from a magazine 16 by rotary pick-out means 17 having picker pads 18.

As can be seen in Figure 2 the pidker pads are provided in known manner on arms 19 guided for radial movement with respect to the axis 20 of rotation of the pick-out means and are reciprocated relative thereto by cranks 21 oscillated about axes 22 by pinion gears 23, which mesh with gear segments 24 carrying follower rollers 25 travelling in a cam track 26.At the position of maximum throw 26X of the cam track each follower roller 25, segment 24 and pinion 23 causes its picker pad 18 to push into the label magazine 16 and, whilst the picker pad is substantially stationary in a rotary sense because of anticlockwise movement of the crank 21 about its axis 22, suction in apertures 27 in the picker pad is able to get hold of the foremost label and withdraw it from the stack as the picker pad moves on its arm 19 radially towards the axis 20 of the pickout means 17. In the region of closest approach of the picker pads 18 to the labelholding pads 13 of the transfer means 14 the cam track 26 is concentric with the axis 20 of the pick-out means, so that rolling contact takes place between a label 15 on a picker pad 18 and a label-holding pad 13 of the transfer means 14.The labelholding pads are also provided with suction apertures 28 to enable the labels 15 to be held by suction until they are rolled in turn on to bottles 10 at the end of the feedworm 12.

The rotary transfer means 14 carries each label 15 past a heater 29 (see also Figures 3 and 4) with heat seal adhesive on the labels facing towards the heater, whereby the adhesive is melted so that it will cause the labels to adhere to the bottles 10. The heater has a reflector 30 with an elliptical section, and an infra-red radiant element 31 having its axis disposed at one focal line 32 of the elliptical reflector, and the rotary transfer means 14 carries each label 15 through the second focal line 33.

As is evident, the elliptical reflector 30 cannot be a complete ellipse, but it extends to a plane 34 substantially at the second focal line 33 and perpendicular to the major axis of the ellipse. Thus a very large percentage of the heat generated by the element 31 can be focussed on to the adhesive on the labels 15, with a very high energy density at the second focal line 33 so that short heating times can be achieved whereby the speed at which the labels can pass the heater 29 matches the speed that can be achieved with the pickout means 17 and the speed with which labels can be rolled on to bottles.

Flat reflectors 35 (which with the elliptical reflector 30 are preferably polished or plated) at the ends of the element 31 and screens 36 defining an aperture 37 around the second focal line 33 limit stray emission to prevent heating up of the machinery and bottles. The elliptical reflector 30 and the end reflectors are provided with passages 38 for recirculating cooling water.

The screens 36 are detachably secured (by means not shown) to the elliptical reflector 30, so as to enable the screens to be changed to change the size of the aperture 37 (particularly in the direction parallel to the second focal line 33) to suit a change in the size of labels.

The infra-red element 31 is preferably a silicon carbide resistance heater ele -ment, which can be operated at 15000 C to enable the machine to operate at high speed. However, the machine is also required to operate at low and medium speeds and, therefore, is provided with a feedback control system for changing the temperature of the element 31 as a function of the labelling speed. The inter-linking circuitry of the feedback control system is housed in a control console 39 for the machine and will not be described in detail, as it is within the skills of any competent electrical-electronic engineer, and the following description will be confined to the feedback and protection devices that art inter-linked by the circuitry.

An adhesive condition sensor 40, which is preferably a light emitting diode sensing the reflectivity of the adhesive, is disposed adjacent the heater 29 to detect that adhesive on a label 15 has been melted by passage past the heater, and is inter-linked to a label inlet sensor 41, so that the adhesive condition sensor only functions when a label is present on a pad 13 of the rotary transfer means 14.The label inlet sensor is inter-linked to a counter switch 42 for putting the machine into a "stand-by" mode, if - for example - more than three successive labels 15 are absent from the rotary transfer means 14, as could result from an empty label magazine 16, the "stand-by" mode being one in which the heater 29 is maintained at the required temperature, but a shutter 43 (movable by a rotary solenoid 44 and arms 45 connected by a link 46) is provided to close the aperture 37, so that overheating of the transfer means does not occur. One or more heat sensors (not shown) may be incorporated in the reflector 30 or reflectors 35 and linked to the feedback control system so that, if the heater fails or the temperature of the element 31 exceeds a set amount, the machine is switched off.

The feedback control system also includes a stop 47 (movable by an air cylinder 48) to prevent bottles 10 entering the machine during the "stand-by" mode, which will also have to be achieved when the machine is first switched on and the heater has to equilibrate at the required temperature before labelling can commence. A bottle detector 49 is provided to cause the absence of a succession of bottles 10 (e.g., three or more) at the feed-worm 12 to put the machine into "stand-by" mode. The label magazine is provided with an air cylinder 50 for moving it from an operative to an inoperative position when a bottle is not detected by the bottle de tector 49 after withdrawal of the movable bottle stop 47, so that a label cannot be carried by the transfer means 14 if there will be no bottle to receive it.A hold-up detector 51 (e.g., a pressure sensitive switch beyond after-roll means 52 for labelled bottles) is provided beside the conveyor 11 leading away from the rotary transfer means 14, so that if there is a hold up in the discharge of labelled bottles from the machine then the machine is put into the "stand-by" mode.

WHAT WE CLAIM IS: 1. A labelling machine comprising a heater having a reflector with an elliptical section and an infra-red radiant element having its axis disposed at one focal line of the elliptical reflector, a magazine for labels bearing heat seal adhesive, and transfer means for transferring individual labels from the magazine to articles to be labelled via the heater with each label passing through the second focal line of the elliptical reflector and with the adhesive towards the heater element, 2. A machine as in Claim 1, wherein the elliptical reflector extends to a plane substantially at the second focal line through which the labels pass.

3. A machine as in Claim 2, wherein the plane to which the elliptical reflector extends is perpendicular to the major axis of the ellipse.

4. A machine as in any one of Claims 1 to 3, wherein flat reflectors are provided at the ends of the element and screens define an aperture around the second focal line of the elliptical reflector.

5. A machine as in Claim 4, wherein the elli tical reflector and the flat reflectors are polished or plated.

6. A machine as in any one of Claims 1 to 5, wherein the elliptical reflector is provided with passages for cooling medium.

7. A machine as in Claim 4 and Claim 6, wherein the flat end reflectors are also provided with passages for cooling medium.

8. A machine as in Claim 4, wherein the screens defining an aperture around the second focal line of the elliptical reflector are detachably secured to the reflector.

9. A machine as in any one of Claims 1 to 8, wherein a feedback control system is provided for changing the temperature of the element as a function of the labelling speed.

10. A machine as in Claim 9, wherein an adhesive condition sensor is disposed adjacent the heater to detect that adhesive on a label has been melted by passage past the heater.

11. A machine as in Claim 10, wherein the adhesive condition sensor consists of a light emitting diode sensing the reflectivity of the adhesive.

12. A machine as in Claim 10 or Claim 11, wherein the adhesive condition sensor is inter-linked to a label inlet sensor, so that the adhesive condition sensor only functions when a label is present on the rotary transfer means.

13. A machine as in Claim 12, wherein the label inlet sensor is inter-linked to a counter switch for putting the machine into a "stand-by" mode, the "stand-by" mode being one in which the heater is maintained at the required temperature.

14. A machine as in Claim 13, wherein a movable shutter is provided to close the aperture defined by the heater screens, so that overheating of the transfer means does not occur.

15. A machine as in any one of Claims 9 to 14, wherein one or more heat sensors is incorporated in the reflector or reflectors and linked to the feedback control system so that, if the heater fails or the temperature of the heater element exceeds a set amount, the machine is switched off.

16. A machine as in any one of the preceding claims also comprising a conveyor for feeding bottles past the rotary transfer means, and spacing and timing means arranging for bottles to be brought to the transfer means in phase with labels carried by the transfer means.

17. A machine as in Claim 16 in combination with any one of Claims 9 to 15, wherein the feedback control system includes a movable stop to prevent bottles entering the machine during the "stand-by" mode.

18. A machine as in Claim 17, wherein a bottle detector is provided in the feed back control system to cause the absence of a succession of bottles at the spacing and timing means to put the machine into "stand-by" mode.

19. A machine as in Claim 18, wherein the label magazine is provided with means for moving it from an operative to an inoperative position when a bottle is not detected by the bottle detector after withdrawal of the movable bottle stop, so that a label cannot be carried by the transfer means if there be no bottle to receive it.

20. A machine as in any one of Claims 16 to 19, wherein a hold-up detector is provided beside the conveyor leading away from the rotary transfer means, so that if there is a hold up in the discharge of labelled bottles from the machine then the machine is put into the "stand-by" mode.

21. A bottle labelling machine substantially as hereinbefore described with refer ence to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (21)

**WARNING** start of CLMS field may overlap end of DESC **. beyond after-roll means 52 for labelled bottles) is provided beside the conveyor 11 leading away from the rotary transfer means 14, so that if there is a hold up in the discharge of labelled bottles from the machine then the machine is put into the "stand-by" mode. WHAT WE CLAIM IS:

1. A labelling machine comprising a heater having a reflector with an elliptical section and an infra-red radiant element having its axis disposed at one focal line of the elliptical reflector, a magazine for labels bearing heat seal adhesive, and transfer means for transferring individual labels from the magazine to articles to be labelled via the heater with each label passing through the second focal line of the elliptical reflector and with the adhesive towards the heater element,

2. A machine as in Claim 1, wherein the elliptical reflector extends to a plane substantially at the second focal line through which the labels pass.

3. A machine as in Claim 2, wherein the plane to which the elliptical reflector extends is perpendicular to the major axis of the ellipse.

4. A machine as in any one of Claims 1 to 3, wherein flat reflectors are provided at the ends of the element and screens define an aperture around the second focal line of the elliptical reflector.

5. A machine as in Claim 4, wherein the elli tical reflector and the flat reflectors are polished or plated.

6. A machine as in any one of Claims 1 to 5, wherein the elliptical reflector is provided with passages for cooling medium.

7. A machine as in Claim 4 and Claim 6, wherein the flat end reflectors are also provided with passages for cooling medium.

8. A machine as in Claim 4, wherein the screens defining an aperture around the second focal line of the elliptical reflector are detachably secured to the reflector.

9. A machine as in any one of Claims 1 to 8, wherein a feedback control system is provided for changing the temperature of the element as a function of the labelling speed.

10. A machine as in Claim 9, wherein an adhesive condition sensor is disposed adjacent the heater to detect that adhesive on a label has been melted by passage past the heater.

11. A machine as in Claim 10, wherein the adhesive condition sensor consists of a light emitting diode sensing the reflectivity of the adhesive.

12. A machine as in Claim 10 or Claim 11, wherein the adhesive condition sensor is inter-linked to a label inlet sensor, so that the adhesive condition sensor only functions when a label is present on the rotary transfer means.

13. A machine as in Claim 12, wherein the label inlet sensor is inter-linked to a counter switch for putting the machine into a "stand-by" mode, the "stand-by" mode being one in which the heater is maintained at the required temperature.

14. A machine as in Claim 13, wherein a movable shutter is provided to close the aperture defined by the heater screens, so that overheating of the transfer means does not occur.

15. A machine as in any one of Claims 9 to 14, wherein one or more heat sensors is incorporated in the reflector or reflectors and linked to the feedback control system so that, if the heater fails or the temperature of the heater element exceeds a set amount, the machine is switched off.

16. A machine as in any one of the preceding claims also comprising a conveyor for feeding bottles past the rotary transfer means, and spacing and timing means arranging for bottles to be brought to the transfer means in phase with labels carried by the transfer means.

17. A machine as in Claim 16 in combination with any one of Claims 9 to 15, wherein the feedback control system includes a movable stop to prevent bottles entering the machine during the "stand-by" mode.

18. A machine as in Claim 17, wherein a bottle detector is provided in the feed back control system to cause the absence of a succession of bottles at the spacing and timing means to put the machine into "stand-by" mode.

19. A machine as in Claim 18, wherein the label magazine is provided with means for moving it from an operative to an inoperative position when a bottle is not detected by the bottle detector after withdrawal of the movable bottle stop, so that a label cannot be carried by the transfer means if there be no bottle to receive it.

20. A machine as in any one of Claims 16 to 19, wherein a hold-up detector is provided beside the conveyor leading away from the rotary transfer means, so that if there is a hold up in the discharge of labelled bottles from the machine then the machine is put into the "stand-by" mode.

21. A bottle labelling machine substantially as hereinbefore described with refer ence to the accompanying drawings.