Abstract
The invention relates to applying a liquid to pasty hot-melt adhesive to a substrate (44), comprising a template (29), having at least one cavity (38) for the hot-melt adhesive, and also comprising an adhesive-transfer infeed (33), which is assigned to the template (29) and through which the adhesive can be introduced into the cavity (38). The special feature consists in that the apparatus (10) further comprises a transporting-fluid-supply opening (35), assigned to the template (29), and a device for displacing (13, 15), in particular pivoting, the template (29) between a first position, in which the cavity (38) is assigned to the adhesive-transfer infeed (33), and a second position, in which the cavity (38) is assigned to the transporting-fluid-supply opening (35), and therefore the adhesive, in the second position, can be discharged from the cavity (38) by a transporting fluid flowing through the transporting-fluid-supply opening (35).
Claims
1. An apparatus for applying a liquid to pasty hot-melt adhesive to a substrate, comprising: a template, having at least one cavity for the hot-melt adhesive, the template having a first side and a second side opposite to the first side; an adhesive-transfer infeed cooperating with the template and through which the adhesive is introduced into the at least one cavity from the first side; a transporting-fluid-supply opening cooperating with the template; a device for displacing the template between a first position, in which the at least one cavity is assigned to the adhesive-transfer infeed, and a second position, in which the at least one cavity is assigned to the transporting-fluid-supply opening, wherein the adhesive, in the second position, is discharged from the at least one cavity at the second side of the template by a transporting fluid flowing through the transporting-fluid-supply opening.
2. The apparatus of claim 1 including a stationary exit opening in communication with the at least one cavity when the template is in the second position, the stationary exit opening positioned opposite the transporting-fluid-supply opening relative to the template.
3. The apparatus of claim 1 including an outflow channel, an inlet of the outflow channel cooperating with the at least one cavity when the template is in the first position, the inlet being arranged opposing the adhesive-transfer infeed relative to the template.
4. The apparatus of claim 1 including sealing walls between the adhesive-transfer infeed and the transporting-fluid-supply positioned on either side of the template.
5. The apparatus of claim 1, wherein the template is operably connected to the displacement device for rotating the template and wherein with each full revolution of the template, the at least one cavity passes by the adhesive-transfer infeed once and the transporting-fluid-supply opening once.
6. The apparatus of claim 1, wherein the template is in the form of an disk having a diameter between 5 and 20 cm.
7. The apparatus of claim 6, wherein the disk has a diameter between 7 and 14 cm.
8. The apparatus of claim 7, wherein the disk has a diameter of about 12 cm.
9. The apparatus of claim 1, wherein the template has a positioning marker and wherein the apparatus has a counter-marker, and wherein alignment of the counter-marker and positioning marker permits initial positioning of the template in the apparatus.
10. The apparatus of claim 1, wherein the apparatus has an opening mechanism for removably replacing the template with an alternative template without the use of tools.
11. The apparatus of claim 1, wherein the at least one cavity has a width of less than or equal to 2 mm.
12. The apparatus of claim 11, wherein the at least one cavity has a width of less than or equal to 1 mm.
13. The apparatus of claim 1, wherein the template includes multiple cavities, the multiple cavities being arranged in a pattern.
14. The apparatus of claim 1 including an air knife for discharging the adhesive from the cavity.
15. An apparatus for applying a liquid to pasty hot-melt adhesive to a substrate, comprising: a template, having at least one cavity for the hot-melt adhesive; an adhesive-transfer infeed cooperating with the template and through which the adhesive is introduced into the at least one cavity; a transporting-fluid-supply opening cooperating with the template; and a device for displacing the template between a first position, in which the at least one cavity is assigned to the adhesive-transfer infeed, and a second position, in which the at least one cavity is assigned to the transporting-fluid-supply opening, wherein the adhesive, in the second position, is discharged from the at least one cavity by a transporting fluid flowing through the transporting-fluid-supply opening, and wherein the template is in the form of an disk having a diameter between 5 and 20 cm.
16. An apparatus for applying a hot-melt adhesive to a substrate, comprising: a template, having at least one cavity for the hot-melt adhesive; an adhesive-transfer infeed cooperating with the template and through which the adhesive is introduced into the at least one cavity; a transporting-fluid-supply opening cooperating with the template; a device for displacing the template between a first position, in which the at least one cavity is assigned to the adhesive-transfer infeed, and a second position, in which the at least one cavity is assigned to the transporting-fluid-supply opening; an outflow channel downstream from the template, an inlet of the outflow channel cooperating with the at least one cavity when the template is in the first position, the inlet being arranged opposing the adhesive-transfer infeed relative to the template; a stationary exit opening downstream from the template in communication with the at least one cavity when the template is in the second position, the stationary exit opening positioned opposite the transporting-fluid-supply opening relative to the template, and wherein the adhesive, in the second position, is discharged from the at least one cavity by a transporting fluid flowing through the transporting-fluid-supply opening.
Description
DESCRIPTION OF THE DRAWINGS
(1) Further advantages of the present disclosure can be gathered with reference to the appended claims in their entirety and from the following description of the exemplary embodiments illustrated in the drawings, in which:
(2) FIG. 1 shows, in a schematic, perspective obliquely illustrated plan view from the front, of an embodiment of the apparatus in a state in which it has not yet been connected to electricity and compressed air;
(3) FIG. 2 shows, in a perspective/schematic obliquely illustrated bottom view from the rear side, the apparatus of FIG. 1, connected neither to an adhesive outflow nor to an adhesive infeed;
(4) FIG. 3 shows, in a further perspective obliquely illustrated bottom view from the front side, the apparatus of FIG. 1 in a partially exploded state and with a first example of a template inserted;
(5) FIG. 4a shows a highly schematic, partially transparent section through the apparatus according of FIG. 3, for example along the seal which, in FIG. 3, is arranged above the template, the seal in FIG. 4a having a modified, essentially square shape, and the template according to FIG. 3, in addition, having been replaced by an alternative template with a different pattern;
(6) FIG. 4b shows, in a view according to FIG. 4a, the apparatus with a template pivoted slightly in the counterclockwise direction;
(7) FIG. 5 shows, in a highly schematic, cut-away basic illustration, a lateral sectional view through the apparatus in the region of the template;
(8) FIG. 6 shows a perspective, highly schematic basic obliquely illustrated plan view of a further alternative template, with adhesive applied to a substrate;
(9) FIG. 7a shows, in a view similar to FIG. 6, the template of FIG. 3;
(10) FIG. 7b shows a highly schematic, cut-away, enlarged plan view of a pattern from the template illustrated in FIG. 7a, the pattern being found approximately in the region VIIb of FIG. 7a; and
(11) FIG. 8 shows a second embodiment in a highly schematic perspective obliquely illustrated bottom view.
DETAILED DESCRIPTION
(12) Ahead of the following description of the figures, it should be noted that, for the sake of simplicity, the same or comparable parts in comparable exemplary embodiments are provided with the same reference signs, in some cases with the addition of lower-case letters or of apostrophes.
(13) A first exemplary embodiment of the apparatus is provided with the reference sign 10 in FIGS. 1 to 3.
(14) FIG. 1 shows, in a perspective schematic obliquely illustrated plan view, in the first instance the basic construction of the apparatus 10. Thus, the apparatus has an application head 11, by means of which the apparatus 10 dispenses adhesive in pattern form onto a substrate, which is arranged beneath the apparatus 10, as seen in relation to FIG. 1, but is not illustrated in FIG. 1. The substrate would be arranged in the vertical direction z beneath the apparatus 10 illustrated in FIG. 1 and could be displaced, for example, linearly in a direction of guidance X.
(15) A template, which will be described in more detail at a later stage in the text, can be introduced into the application head 11 according to FIG. 1, the template being concealed in FIG. 1 since it is arranged in the interior of the application head 11. This template is driven in rotation, in the plane defined by the conveying direction X and the transverse direction Y, by a servomotor 13. The servomotor 13 here acts on the template via a transmission 14 with a shaft 15, which may have, for example, a hexagonal cross section.
(16) The apparatus of FIG. 1, in addition, has a transporting-fluid or compressed-air connection 16, through which a transporting fluid, for example compressed air, can be introduced into the application head 11 in order to discharge the adhesive from the template and the apparatus 10 and to transfer the adhesive onto the substrate. The transporting fluid may be, in particular, heated for this purpose, and an electrical connection 17 is therefore provided, it being possible for the electrical connection to be supplied with power in heating zones arranged in the apparatus 10, but not illustrated explicitly. These heating zones can be used both for heating the compressed air introduced through the connection 16 and for keeping the adhesive introduced into the apparatus 10 warm, and therefore liquid to pasty.
(17) The adhesive is directed into the apparatus 10 via an adhesive connection 18 illustrated in FIG. 2. For this purpose, the connection 18 can have connected to it, for example, a separate hose, which connects the apparatus 10 to a hot-melt store. As an alternative, the connection 18 can also be used to mount the apparatus 10 rigidly (that is to say not via a hose) on an adhesive infeed. In addition, the rear side of the apparatus 10, the rear side being illustrated in FIG. 2, has fasteners 19 in the manner of retaining clamps.
(18) The adhesive, which enters into the apparatus 10 via the connection 18, is directed first of all (in a manner which is not illustrated in FIGS. 1 and 2) into the application head 11, where it can be directed into the template. The adhesive here flows through the template and, in particular, cavities which have been introduced into the template. Displacement of the template thus gives rise, on the one hand, to fractions of adhesive which are displaced along with the template and, on the other hand, when the template is flushed out, in fractions of adhesive which are removed in a manner which will be explained at a later stage in the text. For this purpose, the adhesive, once it has flowed through the template (without being transported along by the template), enters, in particular, into an adhesive-outflow channel in the application head 11 and is then directed to an outflow connection or return connection 20. By means of the connection 20, the adhesive either is directed out of the system or, as an alternative, preferably, is introduced back into the adhesive circuit. For example it is possible for the return connection 20, for this purpose, likewise to be connected to the same store to which the connection 18 is connected.
(19) The adhesive transported along by the template is then discharged from the apparatus 10, out of an exit opening 21 of the application head 11, the opening being illustrated in FIG. 2, at a different location, with the aid of the transporting fluid directed into the apparatus 10 via the connection 16 according to FIG. 1, and applied to the substrate located beneath.
(20) In order to clarify the construction of the application head 11, FIG. 3 shows the application head 11 in an exploded state. As is clear from FIG. 3, the application head 11 comprises, from top to bottom, a base 22, a first seal 23, a frame 24 for the template, a second, lower seal 25 and a nozzle plate 26. As can be gathered from FIG. 3, all the structural elements of the application head 11 here have a multiplicity of assembly openings which are aligned in relation to one another and of which just in each case one assembly opening of each structural element is designated by 27 in FIG. 3. For assembly of the apparatus 10 or of the application head 11, pin-like retaining means 28, such as bolts or screws, can be plugged in a conventional manner through the openings 27.
(21) During assembly here, a template 29 is introduced into the frame 24, that is to say beneath the first seal 23 and above the second seal 25. The template is of round design, in the form of a disk, and has approximately the diameter of a commercially available CD. It has a central engagement opening 30, which may be of, for example, hexagonal design and through which, during assembly, a head 31 of the shaft 15 is plugged in a form-fitting manner.
(22) The template 29 consists, for example, of stainless steel and is provided with cavities which are arranged to form patterns (a plurality of identical patterns in the form of teddy-bear heads are evident in FIG. 3) and are introduced into the disk 29 in the manner of laser cutting.
(23) Purely for the sake of completeness, it should be noted that the apparatus shown in FIGS. 1 to 3 is provided with a single template for the duration of use. It is therefore the case that FIGS. 1 to 3 do not show any means for changing over the template 29 without use being made of tools. In an embodiment, albeit one which is not illustrated in FIGS. 1 to 3, the apparatus 10 may be adapted such that the template 29 can be changed over in the manner of a CD player or CD changer, without use being made of tools. For this purpose, the application head 11 may provide, for example, an ejecting drawer or some other kind of (for example a slot-like) ejecting mechanism, as is also known from commercially available CD players.
(24) The operation of the apparatus 10 illustrated in FIGS. 1 to 3 will now be described. It is thus possible for a hot-melt adhesive to be directed into the apparatus 10 via the adhesive connection 18 illustrated in FIG. 2. The adhesive is then transferred, or directed onward, within the base 22 of the application head 11, from a dispensing opening 32, which is illustrated in FIG. 3, to a transfer opening 33 in the first seal 23. For transportation from the adhesive connection 18 to the transfer opening 33, it is possible to provide pumps, such as piston pumps or the like, in particular upstream of the apparatus 10.
(25) Beneath the transfer opening 33 in the first seal 23, the template 29, which is driven by the shaft 15 and has cavities which can be assigned to the transfer opening 33, rotates within the frame 24.
(26) Accordingly, the adhesive can enter, from the transfer opening 33, into those cavities of the template 29 which are moving past the transfer opening 33. The cavities of the template 29 have in particular the adhesive which is exiting from the transfer opening 33 flowing through them and, once it has passed through the template 29 (at any rate at least in part), the adhesive passes into an outflow opening 34 in the second seal 25. From this outflow opening 34 in the second seal 25, the outflowing adhesive can then pass into an outflow channel within the nozzle plate 26 and, from there, be directed to the return connection or outflow connection 20 illustrated in FIG. 2.
(27) When the template 29 is displaced, however, a sub-quantity of the adhesive flowing through the template 29 is carried along by the template 29, and therefore, rather than passing into the outflow opening 34 in the second seal 25, this sub-quantity remains in the template 29 during displacement of the latter. The adhesive here, once it has entered into the template 29 from the transfer opening 33, is displaced to a fluid opening 35 in the first seal 23.
(28) Exiting through the fluid opening 35 is a transporting fluid, in particular compressed air, which is supplied to the fluid opening 35 via the connection 16, which is illustrated in FIG. 1, and a fluid-transfer opening 36, which is provided in the base 22 and is illustrated in FIG. 3. The fluid exits from the fluid opening 35 with a very sharp edge, the fluid opening 35 and the fluid-transfer opening 36 constituting part of a so-called air knife, which provides high-pressure air which exits discretely with very sharp edges. The geometry of the fluid opening 35 is therefore also very much narrower than the geometry of the fluid-transfer opening 36.
(29) The very sharp-edged compressed air exiting from the fluid opening 35 of the first seal 23 then drives the adhesive out of the adhesive-filled cavities in the template 29 which are being guided past beneath the air. The compressed air, together with the adhesive, is removed from, or blown out of, the apparatus 10 from the template 29, via a dispensing opening 37 in the second seal 25 and the exit opening 21 in the nozzle plate 26, and transferred onto the substrate located beneath.
(30) In respect of the exemplary embodiment of FIG. 3, it should be noted, in conclusion, that the first and second seals 23 and 25 particularly advantageously have coefficients of friction, in order to allow the disk 29 to be displaced within the application head 11 in as friction-free a manner as possible. At the same time, however, the seals 23 and 25 are capable of butting closely enough against the template 29 to be able to perform their sealing function to a sufficient extent.
(31) FIG. 4a shows a section, in plan view, through the apparatus 10, the section being taken, in respect of FIG. 3, approximately level with the first seal 23 and being illustrated in a partly transparent form, in which the template 29 can also be seen.
(32) The template 29 illustrated in FIG. 4a, however, is an alternative template to the template which is illustrated in FIG. 3, since the template 29 according to FIG. 4 has a different pattern. It is also the case that, for reasons of simplicity, the geometry of the first seal 23 has been simplified in the illustration to a square shape (whereas FIG. 3 illustrates a half-rounded seal 23), but, rather than adversely affecting the basic character of the seal, this is merely intended to simplify the illustration.
(33) At any rate, FIG. 4a shows a template with cavities 38 which are arranged in a raster-like manner, for the sake of simplicity only some of these cavities being designated thus in FIG. 4a.
(34) According to FIG. 4a, the template 29 is located in a position in which eight cavities 38, which are arranged in a row 39, are arranged beneath the transfer opening 33 in the seal 23, as yet no cavity 38 being arranged beneath the fluid opening 35. The first row 39 of cavities is thus, according to FIG. 4a, just in the process of being filled with adhesive. The template 29 here, in respect of FIGS. 4a and 4b, is displaced in the pivoting direction S, that is to say is pivoted in a counterclockwise direction, by the shaft head 31 engaging in the engagement opening 30 of the template 29. During this displacement, the template 29 reaches the position which is illustrated in FIG. 4b, and in which the first row 39 of cavities 38 is now arranged beneath the fluid opening 35 of the first seal 23. In this position, the air knife can then blow out the contents of the first row 39 of cavities 38, via the fluid opening 35, in a downward direction as seen in relation to the plane of the figure, that is to say onto a substrate arranged beneath the plane of the figure, through the exit opening 21 (as is illustrated in FIG. 3). In a position according to FIG. 4b, the first row 39 is thus having its contents blown out, whereas the fifth row 40 of cavities 38 is in the process of being charged with adhesive, namely via the transfer opening 33.
(35) The rows of cavities between the first row 39 and the fifth row 40 have been filled with adhesive; those rows of cavities which follow the fifth row 40 are still empty.
(36) In an embodiment, a feature which is illustrated in FIGS. 4a and 4b, is a positioning marker 41 of the template 29, which is designed in the form of a physical notch. The shaft or the shaft head 31, in contrast, has arranged on it a positioning lug 42, which engages in the positioning notch 41. These positioning aids 41 and 42 are essentially not involved in driving the template 29; rather, they are used for correct initial positioning of the template 29 within the application head 11 (or within the frame 24). By virtue of these positioning aids 41 and 42 coinciding, the template can be positioned manually just in precisely one (aligned) position within the application head 11.
(37) This ensures that, each time the apparatus 10 is switched on or started up, the template always has its pattern arranged correctly in relation to the transfer opening 33 and the fluid opening 35 and the exit opening 21.
(38) FIG. 5 is intended to clarify the filling operation of a template 29 and illustrates a highly schematic, lateral sectional view through a template 29 and through the first seal 23, the second seal 25 and the nozzle plate 26 (the material thicknesses of the components being illustrated in distorted form in FIG. 5 for reasons of clarity).
(39) FIG. 5 illustrates a snapshot in which a first cavity 38a has not yet been filled with adhesive. A second cavity 38b, according to FIG. 5, is in the process of having adhesive flowing through it, the adhesive being directed into the cavity 38b via the transfer opening 33 in the first seal 23. On the underside of the cavity 38b, the adhesive flowing through can enter into the second seal 25, to be precise into the outflow opening 34. From the outflow opening 34, the adhesive then passes into an outflow channel 43 in the nozzle plate 26, via which it passes (via further channel portions which are not illustrated) to the outflow connection or return connection 20 according to FIG. 2.
(40) FIG. 5 also shows a third cavity 38c, which has already been filled, but is not yet emptied. Finally, FIG. 5 illustrates a fourth cavity 38d, which has just been emptied by the air knife, using compressed air supplied via the fluid opening 35. Accordingly, the adhesive located in the cavity 38d has just been removed from the apparatus 10 via the dispensing opening 37 and via the exit opening 21.
(41) It can also be seen in FIG. 5 that the exit opening 21, and in particular also the dispensing opening 37, are designed to be wider than the cavity 38d. This allows optimized discharge of the adhesive from the cavity 38d.
(42) In respect of FIG. 5, it should be noted that the chambers in the present exemplary embodiment all have the same width b, which in the present exemplary embodiment is somewhat less than one millimeter, and it should be pointed out that the cross-sectional illustration of the disk 29 is distorted, since the individual cavities 38, on account of the rotary arrangement on the round disk, would not actually be located in a section plane. In sectional illustration, the cavities 38 have thus been projected into a common section plane, in order for the filling and emptying operations of the cavities to be explained purely schematically.
(43) And, in respect of FIG. 5, reference is also made to the walls 50a of the upper seal 23 and 50b of the lower seal 25, the walls sealing the disk 29 and/or the cavities, in particular cavity 38c, arranged in this region. In an alternative embodiment, however, it is also possible to dispense with the walls 50a and 50b, in particular the lower wall 50b, if it is ensured that the adhesive remains in the cavity 38 on account of surface tensions or the like. In such an exemplary embodiment, the exit opening of the apparatus could then be provided by the underside of the cavity 38 itself.
(44) FIG. 6 shows, in a highly schematic illustration, a further exemplary embodiment of a template 29, with a bar-like application pattern 45 on the substrate 44. It is clear from FIG. 6 here that the application pattern 45, in terms of its geometrical shape, in the first instance clearly differs from the pattern 46 as is actually provided in the template 29. Whereas the application pattern 45 has its outer contour formed in the shape of a rectangle (and thus has right angles), this is not the case for the contour of the pattern 46 which is actually introduced into the template 29. Rather, the pattern 46 has curved outer contour lines 47a and 47b. The patterns 45 and 46 differ from one another as a result of the rotary displacement of the template 29 along the displacement direction S, which naturally differs from the linear displacement direction or conveying direction X of the substrate 44. Since the aim is for a desired application pattern 45 to be applied to the substrate, it has been found in practice to be advantageous to provide software which a user can use to predetermine their desired application pattern 45. The software, then, automatically calculates the shape of the actual pattern 46 on the template and can initiate appropriate cutting of cavities on a template blank.
(45) It is also clear from FIG. 6 that large-surface-area application patterns, such as the application pattern 45 according to the present invention, are, in principle, rasterized. In other words, rather than a single large cavity being provided within the template 29, the template actually contains a multiplicity of small cavities 38 arranged, and distributed uniformly, within a desired contour.
(46) FIG. 7a shows, in a view according to FIG. 6, the template 29 as can already be seen in FIG. 3. The template has a plurality of patterns 46a to 46j, all of identical configuration. In an alternative embodiment, these patterns 46a to 46j could also be varied. It is clear from FIG. 7a here that the individual template patterns 46a to 46j are arranged in annular form in relation to one another, whereas the patterns, when actually applied to the substrate, are arranged in linear form, that is to say in a row.
(47) FIG. 7b shows an enlarged illustration of the template pattern 46d in FIG. 7a. It is clear from FIG. 7b here that the pattern 46d, rather than being of continuous design, actually comprises numerous small cavities or sub-cavities 38a to 38s. To this extent, rasterization is also provided for such patterns, each of the cavities 38a to 38s having a width of less than one millimeter. To this extent, all the cavities 38a to 38s are of identical width, but vary in length.
(48) Finally, FIG. 8 shows a second exemplary embodiment of an apparatus 10′ according to the invention. The template 29′ here is designed, in a rotationally symmetrical manner about a pivot axis a, in the form of a cylinder surface or cylinder tube 29′, which rotates about the longitudinal axis a along the direction of rotation r. In the same way as for the exemplary embodiment of FIGS. 1 to 7, the individual exit openings of the individual patterns 46′ in the template 29′ here are likewise guided past an exit opening 21′, which is arranged in a central body 47.
(49) On its side assigned to the inside of the template 29′, as is indicated merely schematically in FIG. 8, the central body 47 has connections 16′, 17′, 18′ and 20′ for compressed air, power and adhesive and also has an adhesive outflow. The construction of the central body 47 here may be essentially identical to the construction of the application head 11 belonging to the apparatus 10 according to FIGS. 1 to 7.
(50) In particular, the central body 47 has a cross section which corresponds essentially to FIG. 5. Accordingly, alongside the exit opening 21′ illustrated in FIG. 8, the central body 47 of course also contains within it an outflow opening for the adhesive and a fluid opening for providing an air knife, by means of which the adhesive (which is transported from the transfer opening to the fluid opening along the direction of rotation r) is then transferred, via the exit opening 21′, onto the substrate, which is arranged beneath the central body 47, but is not illustrated in FIG. 8.
(51) FIG. 8 essentially makes clear the fact that the template need not be designed in the form of a disk. Rather, it may also be designed in tubular form. However, a rotary body is always advantageous, be this in the form of a disk 29 or in the form of a cylinder tube 29′, since this allows a rotary operation which can guide the cavities endlessly past the exit opening.
