GB1595112A

GB1595112A - Apparatus and method for applying hot melt

Info

Publication number: GB1595112A
Application number: GB18411/78A
Authority: GB
Original assignee: Akerlund and Rausing AB
Current assignee: Akerlund and Rausing AB
Priority date: 1977-05-09
Filing date: 1978-05-09
Publication date: 1981-08-05
Also published as: JPS53139645A; SE418253B; DE2819562A1; SE7705342L

Description

(54) APPARATUS AND METHOD FOR APPLYING HOT MELT (71) We, AB AKERLUND & RAUS ING, a Swedish Company of Fack S-221 Ol Lund 1, Sweden, do hereby decLare the in vention for which we pray that a patent may be granted to ws, and the method by which it is to Ibe performed, to be particularly described in and by the following statement: - The present invention relates to an apparatus and method for applying hot melt to a work piece, and is relates in platiow1ar, but not exclusively, to a packaging machine including a device for applying hot melt to carton blanks.

In machines for erecting plane carton blanks to form tray-shaped packages, it is known to use hot melt for locking the joint flaps of the blanks aster the blanks have been erected in forming shafts. The device for applying the hot melt is usually located in front of the forriag shaft in order to avoid complex tool constructions.

The known devices are basically so arranged that moving arms are immersed in trays con taining hot melt, the hot melt being heated by separate heating elements in the tray. In operation, the arms move to take up the heated hot melt and transfer the same for application to appropriate surface areas of the blank. During this operation the appli orator portions of the arms carrying the hot melt have to be moved out of the hot melt in the container. This produces cooling of the hot melt applicators and leads to certain undesirable effects.In particular, the hot melt cools and forms filaments on the applicators with the result that subsequent transfer of hot nielt deteriorates. This deterioration often becomes so serious that the intended function completely fails.

According to the present invention there is provided apparatus for applying hot melt to a work piece, the apparatus comprising an open-topped container for hot melt, ap plicator means for transferring hot melt from the container to a work piece by substantially vertical reciprocating movement of the ap plicator means into and out of the container, and heater means for heating the melt in the container, the heater means being coupled to the applicator means in such a manner as to move with the applicator means, and to transfer heat to the applicator means, while the applicator means is transferring mçlt from the container.

The applicator means may be mounted on and supported by the heater means.

Preferably the heater means is so positioned as to remain, throughout the movement of the applicator means, below the level of hot melt provided in the contaiar in normal operation.

In one preferred arrangement the heater means comprises a heated, heat-conducting plate, for example made of metal In a particularly preferred arrangement, the apparatus according to the invention forms part of a packaging machine for erecting plane carton blanks, the carton blanks constituting the said work piece to which the hot melt is applied.

There is also provided in accordance with the present invention a method of applying hot melt to a work piece comprising the steps of heating the melt in an open-topped container by a heater means transferring hot melt from the container to a work piece by substantially vertical reciprocating movement of the applicator means into and out of the container, the method including moving the heater means with the applicator means and transferring heat from the heater means to the applicator means during the movement of the applicator means.

The method according to the invention also finds particular advantage where the said worlopiece is constituted by a carton blank for erection into a package in a packaging machine.

The embodiments of the invention may be constructed in which the formation of fila- ments from the hot melt is eliminated or reduced because the applicator means are not sulbjected to the cooling which inherently occurs in known devices. This improvement results from the heater means transferring heat to the applicator means which is therefore maintained at substantially the same temperature as the heater means, i.e. at a temperature above or equal to the temperature of the hot melt in the container.

In order to achieve uniform heat distri- bution in the hot melt container, the heater plate is preferably in the form of a plate having substantially the same shape as the crosssection of the hot melt container. Also, apertures are preferably formed in the plate to effect stirring of the hot melt and this assists in achieving uniform temperature in the whole of the container. Such apertures preferably consist of slots in which supports for the applicator means are adjustably mountable.

In order to facilitate uniform application of hot melt onto a work piece, for example the joint flaps of a carton blank, the appli cater means preferably include," one Of more pins, each one of which has a head with an annular groove formed therein to accom- modate hot melt and to apply the same onto the canon blank. This annular groove allows the hot melt to flow therefrom radially inwardly and outwardly and this affords a uniform distribution of the hot melt.

An embodiment of the preset invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows in side view a tray erecting machine incorporating an embodiment of the invention; Figure 2 shows an end view of the machine in Figure 1 seen from the left end in Figure 1, but in a different operating position; Figure 3 is a partial view showing parts in the machine shown in Figures 1 and 2; Figure 4 shows some of the parts shown in Figure 3, seen from above; Figure 5 shows schemiatically the operating mechanism in the tray erecting machine in corp orating the embodiment of the invention shown in the preceding Figures;; Figure 6 shows an applicator pin included in Sthe embodiment shown in the preceding Figures; and Figure 7 shows a support for a pin as shown in Figure 6.

A fully detailed description of the tray erecting machine shown in Figures 1 and 2 is not regarded as necessary to an under standing of the present invention, but such a description is given Zin our co-pending U.K.

Patent Application No. 9787/78 (Serial No.

1,595,111). However, it is appropriate briefly to describe the main parts of the machine for an understanding of the present invention.

In a machine stand 10 there are sup ported a pair of rocker arms 11 and 12.

The rocker arm 11 provides upwards and downwards movement to a plunger 13 which is passed through a forming shaft and erects tray blanks transported from a storage means 14. Transportation from the storage means 14 is controlled by the rocker arm 12 which is synchronized to the rocker arm 11 and is driven from a cam shaft 15 in the machine.

The rocker arm 12 controls a gripper 16 which transports the blanks forwards to a processing station 17. The apparatus which embodies the present invention in this example is located at this station. Tranisporbatiion of the bilanks from the processing station 17 to the forming shaft is effected by a reciproacateiry chain conveyor. This conveyor is driven by a sector-shaped gear 18 which is controlled by a cam disk 20 via a belicrank lever 19 and a cam follower Sarm 21.There is a groove in one surface of the cam disk 20 and the cam follower arm 21 is guided by a cam follower roller 22 engaged in this groove. A further cam follolwef arm 23 and a cam follower roller 24 are guided by the groove in the cam disk 20. The arm 23 is operatively connected to the apparatus embodying the present invention.

After this brief description of the general construction of the machine, a more detaIled description of said embodiment incorporated therein will now be made with reference to Figures 2 to 7.

As seen from Figure 2, the arm 23 is operatively connected to a vertical rod 26.

At 26 this rod is journalied for vertical recd- procatory movement. This movement is controlled by the arm 23 in relation to the cam disk 20. The drive for the cam disk has not been described but it is understood that the driving force for all movable elements is provided by a single motor 27. At the upper end thereof, the rod 25 is rigidly connected to a horizontal transverse rod 28.

There are several pins 29 mounted on the rod 25, which pins pass through guides 30 in a horizontal baffle plate 31, and at the upper ends thereof the pins, in pairs, support horizontal rods 32 arranged to follow the reci- procatcry movement of the rods 25 and the pins 29. Each rod 32 carries at its outermost end a bracket 33. The brackets 33 are engaged in guides 34 and thus follow the vertical reciprocatory movement of the rods 32. Each of the brackets 33 supports a plate 35. The plates 35 are heat conducting memhers and are constructed to be heat-dosssplating and are located in the respective hot melt containers 36. Figure 4 shews that each plate 35 has a rectangular shape substantially corresponding to the cross-section of its hot melt container 36. Also Figure 4 shows that the plates are formed with longitudinal slots 37.

Electrical heating elements (not shown) are incorporated in the plates between the slots thereof. In the slots 37 there are located supports 38 for applicator pins 39. Each support 38 is formed with a rib 40 to adjustably engage one of the slots 37. The supports are locked in place in the relevant slots by inserting locking bolts into holes 41 passing through the ribs.

As seen in Figure 3, the pins 39 are pre fierably attached to the support plate 13 under the action of compression springs 42. The pins will therefore be resiliently applied against the carton blank. Preferably the head 43 of each pin is shaped as shown in Figure 6 with a central portion 44 surrounded by an annular groove 45.

It should be mentioned that the heating plate 35, and also the supports 38 and the pins 39, are suitably manufactured from a good heat-conducting material, such as copper or brass.

Although the operation of the illustrated embodiment is already evident from the foregoing description, the operation will now be briefly described.

Each container 36 is filled with bot melt up to such a level that the heads 43 and the pins 39 are located well below the upper surface of the hot melt when in their lowermost position. The heating eleents of the plates 35 are activated and the power supply to the elements is set at such a level that the hot melt assumes the desired working temperature.

The vertical reciprocation of the rod 25 controlled by the cam follower arm 23 is applied to the transverse rod 28, the pins 29, the rods 32, and the brackets 33 when the machine is operating. Each support plate and the pins 39 follow this movement sc that the heads 44 of the pins are cyclically brought below the upper surface of the hot melt in the container 36 and then above the said surface to engage a blank transported to the processing station 17.

The pins 39 will maintain the temperature substantially the same as that of the respective plate 35, even when the heeds 43 are located above the level of the hot melt, and this avoids the formation of ffliameias on the applicator pins such as mentioned in the introduction of this specification.

Also, the specific shaping of the heads of the applicator pins such that each head has an annular groove 45, facilitates uniform ap plication of hot melt from the pins onto the blank.

Furthermore, since the supports 38 are seen to be formed with an array of holes 46 for receiving the pins, the pins can be selectively located in numerous positions in the supports. In addition the supports 38 can be adjustably located in the slots 37. These adjustments allow account to be taken of ddfer- ent sizes and shapes of blank transported to the processing station 17.

Although the invention has been described with more particular reference to a specific tray erecting machine, it will be appreciated that the invention is capable of variation within the scope of the appendant claims and can be applied to other types of machines.

The only practical limitation thlat exists, in connection with the embodiment illustrated, is that the hot melt necessarily has to be applied from the under side of the blank.

However this is completely acceptable in most applications.

WHAT WE CLAIM IS: 1. Apparatus for applying hot melt to a work piece, the apparatus comprising an open topped container for hot melt, applicator means for transferring hot melt from the container to a work piece by substantially vertically reciprocatory movement of the ap plicator means into and out of the con tainer, and heater means for heating the melt in the container, the heater means being coupled to the applicator means in such a manner as to mov with the applicator means, and to transfer heat to the applicator means, while the applicator means is transferring melt from the container.

2. Apparatus according to Claim 1 in which the applicator means is mounted on and supported by the heater means.

3. Apparatus according to Claim 1 or Claim 2 in which the heater means is so positioned as to remain, throughout the movement of the applicator means, below the level of hot melt provided in the container in normal operation.

4. Apparatus according to any preceding Claim in which the heater means incorporates electrical heating elements.

5. Apparatus according to any preceding Claim in which the heater means comprises a heatfflconducting plate arranged to be heated in operation and to transfer heat to hot melt in the container.

6. Apparatus according to Claim 5 in which the plate has substantially the same shape as the cross-section of the container for hot melt.

7. Apparatus according to Claim 5 or Claim 6 in which the plate is apertured to act as a stirrer for the hot melt.

8. Apparatus according to Claim 7 wherein the applicator means includes a support adjustably connectable with one or mere apertures in the plate.

9. Apparatus according to Claim 8 wherein said piate is apertured wilth at least one slot, and said support has a nib to adjustably engage said slot.

10. Apparatus according to any preceding Claim wherein said appLicator means includes at least one pin having a head formed with an annular groove to accommodate hot melt for application to the work piece.

11. Apparatus according to Claim 10 wherein said pin is supported resiliently.

12. Apparatus according to any preceding Claim wherein said appLicator means com

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. are locked in place in the relevant slots by inserting locking bolts into holes 41 passing through the ribs. As seen in Figure 3, the pins 39 are pre fierably attached to the support plate 13 under the action of compression springs 42. The pins will therefore be resiliently applied against the carton blank. Preferably the head 43 of each pin is shaped as shown in Figure 6 with a central portion 44 surrounded by an annular groove 45. It should be mentioned that the heating plate 35, and also the supports 38 and the pins 39, are suitably manufactured from a good heat-conducting material, such as copper or brass. Although the operation of the illustrated embodiment is already evident from the foregoing description, the operation will now be briefly described. Each container 36 is filled with bot melt up to such a level that the heads 43 and the pins 39 are located well below the upper surface of the hot melt when in their lowermost position. The heating eleents of the plates 35 are activated and the power supply to the elements is set at such a level that the hot melt assumes the desired working temperature. The vertical reciprocation of the rod 25 controlled by the cam follower arm 23 is applied to the transverse rod 28, the pins 29, the rods 32, and the brackets 33 when the machine is operating. Each support plate and the pins 39 follow this movement sc that the heads 44 of the pins are cyclically brought below the upper surface of the hot melt in the container 36 and then above the said surface to engage a blank transported to the processing station 17. The pins 39 will maintain the temperature substantially the same as that of the respective plate 35, even when the heeds 43 are located above the level of the hot melt, and this avoids the formation of ffliameias on the applicator pins such as mentioned in the introduction of this specification. Also, the specific shaping of the heads of the applicator pins such that each head has an annular groove 45, facilitates uniform ap plication of hot melt from the pins onto the blank. Furthermore, since the supports 38 are seen to be formed with an array of holes 46 for receiving the pins, the pins can be selectively located in numerous positions in the supports. In addition the supports 38 can be adjustably located in the slots 37. These adjustments allow account to be taken of ddfer- ent sizes and shapes of blank transported to the processing station 17. Although the invention has been described with more particular reference to a specific tray erecting machine, it will be appreciated that the invention is capable of variation within the scope of the appendant claims and can be applied to other types of machines. The only practical limitation thlat exists, in connection with the embodiment illustrated, is that the hot melt necessarily has to be applied from the under side of the blank. However this is completely acceptable in most applications. WHAT WE CLAIM IS:

1. Apparatus for applying hot melt to a work piece, the apparatus comprising an open topped container for hot melt, applicator means for transferring hot melt from the container to a work piece by substantially vertically reciprocatory movement of the ap plicator means into and out of the con tainer, and heater means for heating the melt in the container, the heater means being coupled to the applicator means in such a manner as to mov with the applicator means, and to transfer heat to the applicator means, while the applicator means is transferring melt from the container.

11. Apparatus according to Claim 10 wherein said pin is supported resiliently.

prises a support formed with an array of holes, and at least one pin selectively locatable in one of said holes to project from said Support.

13. A packaging machine for erecting plane carton blanks, inoorporating apparatus for applying hot melt to the blanks according to any preceding claim.

14. A method of applying hot melt to a work piece cornpísing the steps of heating the melt in an op en- topped container by a heater means, transf erring hot melt from the container to a work piece by substantially vertical reciprocatory movement of the ap plicator means into and out of the container, the method including moving the heater means with the applicator means and transferring heat from the heater means to the applicator means during the movement of the applicator means.

15. A method of erecting plane carton blanks in a packaging machine, the method including a method of applying hot melt to the carton blanks according to Claim 14.

16. Apparatus for applying hot melt to carton blanks substantially as hereinbefore described with reference to the accompanying drawings.

17. A packaging machine for erecting carton blanks substantially as hereinbefore aes- bribed with referenoe to the accompanying drawings.

18. A method of applying hot melts to carton blanks substantially as hereinbefore described with reference to the accompanying dramning6.