GB2090548A - A hotmelt applicator - Google Patents

Abstract

A hotmelt applicator, for carton-, tray-, folding box- or similar type of erectors requires heating of the hotmelt to an applicable state in the output part proper, which comprises at least one applicator pin (15) having a spring loaded ball valve. The applicator is arranged directly adjacent a forming shaft of an erecting tool, and said pin is arranged for supplying a predetermined amount of hotmelt by pressing the blank (19) against a support carrying the blank and movable between a blank supporting position above a forming shaft of the erecting tool and a withdrawn position in which the blank can be pushed into the forming shaft. <IMAGE>

Description

SPECIFICATION A hot melt applicator The present invention relates to applicators for so called hotmelt.

It is known to apply hotmelt onto packaging blanks (i.e. blanks for erection into packages such as cartons, trays, folding boxes, etc.) by use of fluid pressure operated so-called hotmelt guns. Such known arrangements are, however, very expensive and space demanding, so that one frequently tries to find alternatives to the use of hotmelt although hotmelt as such is favourable in packaging applications.

In addition to pressurized fluid systems for automatic supply of hotmelt by spraying through holes of a very small diameter, in the range of some hundreds of a millimeter, there are also known several fully mechanically operating systems based on applicator wheels or "fingers" in one or another form for elevating hotmelt from a bowl to a desired position on the blank. The latter system has certain drawbacks where among other things the limited possibility of arbitary orientation of the application direction of the hotmelt is a drawback. The arrangement also involves the risk of heavy contamination of the erecting device where it is mounted. Further, open hotmelt bowls produce an annoying smell.

An open system is also known where the applicator unit as such has merits, but the open system together with the bulk construction imply an overall construction which leaves quite a lot to be desired. It is for instance not possible to mount the applicator directly adjacent an erecting tool of an erecting device.

Thus, there exists a need for a more feasible and rational arrangement for hotmelt application in for instance a carton erecting device.

The concept of the present invention is based partly on a known method of applying cold glue, partly on the utilization of an essential feature of a recently developed hotmelt applicator system, where so to speak the heating unit of the applicator is divided into two steps, the heating of the hotmelt to an applicable state being carried out first in the ''gun-unit" proper.

The invention inter alia solves the problem of disturbing the path of movement of the blank through the erecting device shaft in a simple but unexpected manner. According to the invention, there is provided a device for application of hotmelt to a packaging blank comprising an applicator device for said hotmelt movable towards and away from, respectively, the blank in an erecting tool. The applicator comprises at least one applicator pin having a spring loaded bali valve. The device is characterized in that the applicator is arranged directly adjacent a forming shaft of the erecting tool, and in that said pin is arranged for delivering a predetermined amount of hotmelt by pressing the blank against a support carrying the blank and positionable into and out from, respectively, the forming shaft of the erecting tool.The invention has particular, but not exclusive application to blanks for erection into carbons, trays and folding boxes.

Erecting devices of the type proper are usually operating vertically, and therefore the support preferably is arranged for rotation around a generally horizontal shaft during the control of a plunger cooperating with the tool.

The applicator pins preferably operate on the upper side of the blank where the support temporarily carries the blank along at least two opposite side edges forming parts of the side walls of the erected package. A reversed embodiment is also possible.

In order to avoid damage of the blank when pushing it down in the forming shaft, the rotational movement of the support is synchronized to the movement of the plunger in the erecting device, so that the support is rotated away from the blank when the effective plunger movement starts.

In order to illustrate the inventive idea, an illustrative embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a schematic over-all view of an erecting tool seen from above, Figure 2 shows the same tool partly in section, Figure 3 is a schematic perspective view of an applicator pin and its immediate environs, and Figure 4 is a view similar to the one in Fig.

3, but showing a later phase during the blank erection procedure.

The tool in Figs. 1 and 2 is for instance intended to form part of automatic erection machinery of the type available under the Trade Mark STA-LOX. Generally, the machinery comprises a vertical forming shaft 11 and a plunger 10 cooperating therewith and arranged for reciprocating upwards and downwards movement.

On a support plate 1 3 in the tool there is carried a hotmelt applicator pin arrangement 14 also arranged for vertical reciprocating upwards and downwards movement on two opposite sides of the shaft 11. The hotmelt applicator pin arrangement comprises two sets each of two applicator pins 1 5. Each pin basically consists of an outer casing, a valve and a spring and acts essentially as a pressure sensitive "ball pen".

The reciprocating upwards and downwards movement is obtained along vertical guides 1 7 by a pressurized fluid plunger/cylinder 16, whereby the applicator arrangement is supported by a horizontal bracket 1 8.

In Fig. 3 it is shown ssìOW a blank 1 of cardboard or similar material is placed over the shaft 11 resting on supports 12. In the position in Fig. 3, the applicator 14 is in its uppermost position, as is the plunger 10.

It should be noted that the applicator pins 1 5 are directly connected to the output part 20 of a two-step heated, closed hotmelt unit, where the final heating to application temperature is carried out in the part 20. (The hotmelt unit as such is not shown in rigs. 3 and 4).

The two (in total 3 in the tool) applicator pins 1 5 shown in Fig. 3 are intended for applying onto the long side wall panel of the blank 1 9, a pair of hotmelt dots when pressing the ball valves o the pins 1 5 against the blank 1 9. Such a pressing is obtained by vertical downwards movement of the applicator 14 by means o the plunger/cylinder device 1 6 for obtaining abutment of the pins 1 5 against the blank 1 g whilst said blank is supported by the support 1 2. This movement advantageously also may be carried out mechanically over a curve dish.

After the operation just described, the applicator 14 returns to its uppermost position and the plunger 10 starts the movement thereof downwards under the action of a mechanism (not shown) intended therefor. At about the same time, the supports 1 2 start their rotation away. This occurs around shafs 22 under the action of a pressurized fluid plunger/cylinder device 23.

A support 1 2 is shown in a rotated-away position in Fig. 4, whereby the plunger 10 is moving down through the forming shaft 11 and starts the erection of the bland 19.

There has been shown and described a preferred arrnngement r applying hotmelt and emphasis has been laid on the basically important parts in connection therewith. The inventive idea is of course not limited thereto, but modifications and alternatives are possible within the scope of the following claims.

Claims (8)

1. A device for applying hotmelt to a packaging blank, comprising an applicator device for said hotnielt displaceable towards and away from said blanks, said applicator device comprising at least one applicator pin having a spring loaded ball valve, wherein said applicator is arranged directly adjacent an erecting tool of an erecting device, and said pin is arrranged for supplying a predetermined amount of hotmelt to the blank by pressing said blank against a support carrying the blank and movable between a blank support ing position above a forming shaft of the erecting tool and a withdrawn position in which the blank can be pushed into the forming shaft.

2. A device as claimed in Claim 1, wherein said support is rotatable around a generally horizontal shaft.

3. A device as claimed in Claim 2, wherein said shaft is synchronized to the movement of a plunger of the erecting tool so that the support is rotated away from the blank when the effective plunger movement starts.

4. A device as claimed in Claim 2 or Claim 3, wherein said at least one applicator pin acts on the upper face of the blank, and the support temporarily supports the blank along at least two opposite side edges forming parts of the side walls of the package to be erected from the blank.

5. A device as claimed in Claim 4, wherein the rotation of the support and the movement of the plunger are carried out in such a manner that the pushing down of the blank into the forming shaft is permitted without deformation of the blank.

6. A device as claimed in Claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.

7. A method of applying hotmelt to a packaging blank employing a device as claimed in any one of the preceding Claims.

8. A method as claimed in Claim 7 and substantially as hereinbefore described with reference to the accompanying drawings.