Abstract
The invention relates to a device for providing adhesive without an adhesive basin, including a conveyor unit, having a first conveying device, a first inlet and a first outlet, through which an adhesive present at least in part as a solid is conveyed, and further comprising a heating unit, having a second inlet and a second outlet, and a first heating device for softening and/or liquefying the adhesive. In order to provide an efficiently and cleanly working device and a method for providing adhesive, a dosing unit having a dosing inlet, a longitudinal slit and a roller is provided.
Claims
1. A device for providing adhesive (1) without an adhesive basin, comprising: a conveyor unit (4), having a first conveying means, a first inlet (3) and a first outlet (6) through which an adhesive present at least in part as a solid is conveyed, a heating unit (7), having a second inlet (9) and a second outlet (10a), as well as a first heating means for softening and/or liquefying the adhesive, and a dosing unit (14) having a dosing inlet (10b), a longitudinal slit (11) as well as a roller (13), wherein the dosing unit (14) is assigned a means for applying a colored substance and/or a dye adjacent to the adhesive layer.
2. The device according to claim 1, wherein a first closing device and/or a second closing device are arranged between the conveying and heating unit (4, 7), or respectively between the heating and dosing unit (7, 14), and are each controllable and/or regulatable.
3. The device according to claim 2, wherein the closing device is designed as a ball valve (12).
4. The device according to claim 1, wherein the heating unit (7) has a second conveying means.
5. The device according to claim 1, wherein the first heating means is designed as an at least single-stage heating coil (19, 20).
6. The device according to claim 1, wherein the heating means are controllable and/or regulatable, wherein at least one temperature sensor interacts with the control and/or regulating unit.
7. The device according to claim 1, wherein the dosing unit (14) has a means for the longitudinal adjustment (23) of the longitudinal slit (11).
8. The device according to claim 1, wherein the dosing unit (14) has a means for adjusting the width of the longitudinal slit (11).
9. The device according to claim 1, wherein the dosing unit (14) has means for closing the longitudinal slit (11).
10. The device according to claim 1, wherein the roller (13) is assigned a means for evening out an adhesive layer placed on the roller.
11. The device according to claim 1, wherein the roller (13) is equipped with means (51) for swinging or pivoting.
12. The device according to claim 1, wherein the first and/or the second conveying means are designed as a screw or extruder.
13. The device according to claim 1, wherein means for processing and/or providing thermoplastic hot melt adhesive are provided, preferably in the form of polyurethane granules.
14. (canceled)
15. A method for providing adhesive by using a device according to claim 1, wherein, wherein an adhesive at least partially present as a solid is placed under a conveying pressure in a conveyor unit (4) and conveyed into a heating unit (7) in which the adhesive is softened and/or liquefied under the effect of heat, and is conveyed into a dosing unit (14), wherein the heated and/or liquefied adhesive is deposited on a roller (13) through a longitudinal slit (11), and wherein a means is provided for applying a colored substance and/or a dye adjacent to the adhesive layer.
16. A dosing unit (14) for providing adhesive, having a dosing inlet (10b), a longitudinal slit (11), as well as a roller (13).
17. (canceled)
18. The new device according to claim 13, wherein the means for processing and/or providing thermoplastic hot melt adhesive process and/or provide the thermoplastic hot melt adhesive in the form of polyurethane granules.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Details of the invention are explained in greater detail below using exemplary embodiments. In the figures:
[0038] FIG. 1 shows a schematic representation of an exemplary embodiment of the device according to the invention for providing adhesive in a side view;
[0039] FIG. 2 shows a schematic representation of the conveyor unit from FIG. 1 in a cross-section;
[0040] FIG. 3 shows a schematic representation of an exemplary embodiment of the heating unit in a side view;
[0041] FIG. 4 shows a schematic representation of an exemplary embodiment of the dosing unit with an assigned scraper in a section transverse to the rotational axis of the roller;
[0042] FIG. 5a shows a focused schematic representation of an exemplary embodiment of the longitudinal slit in the dosing unit;
[0043] FIG. 5b shows a schematic representation of an alternative embodiment of the longitudinal slit in a front view;
[0044] FIG. 5c shows a schematic representation of an alternative embodiment of the longitudinal adjustment of the longitudinal slit in a front view;
[0045] FIG. 6 shows a schematic front view of an exemplary embodiment of the device according to the invention for providing adhesive with a means for applying a colored substance and/or dye;
[0046] FIG. 7 shows a schematic exploded representation of a roller;
[0047] FIG. 8 shows a schematic representation of a roller with a hinge and latch;
[0048] FIG. 9 shows a schematic representation of a dosing unit with a swung-away roller.
DETAILED DESCRIPTION
[0049] FIG. 1 shows a device for providing adhesive 1. This comprises a conveyor unit 4, a heating unit 7 and a dosing unit 14. The conveyor unit 4 is surrounded by a tubular first housing 5, the heating unit 7 is surrounded by tubular second housing 8, and the dosing unit 14 is surrounded by a block-shaped third housing 15. The tubular housings 5, 8 are made from a stainless, temperature-resistant steel that is coated on the inside with an anti-adhesive agent; the block-shaped housing 15 was made from aluminum. The housings 5, 8, 15 can as needed alternatively be made of steel, aluminum, copper, a temperature-resistant plastic, ceramic or a glass-like material. Between each of the units 4, 7 and 14, there is a ball valve 12 that, when in an open position, connects these units with each other in an air- and gas-tight matter, and that separates them from each other when in a closed position. The conveyor unit 4 is moreover assigned a funnel-shaped reservoir 2 in which a particulate PUR is located. Alternative to PUR, any other thermoplastic adhesive can also be used. The reservoir 2 is made of aluminum and does not react with the PUR. In addition, the reservoir 2 ensures a continuous supply of new PUR to the conveyor unit 4. The PUR moves downward out of the reservoir 2 under gravity through a first inlet 3 into the conveyor unit 4 where the PUR is collected by a screw conveyor and conveyed up to a first outlet 6 in the direction of the conveying direction F. The screw conveyor subjects the PUR to a conveying pressure of approximately 30 bar so that the adhesive is pressed through a ball valve 12 and through second inlet 9 into the heating unit 7. Alternatively, conveying pressures between 0.1 bar and 100 bar can be realized. In the heating unit 7, energy is supplied to the PUR in the form of heat, whereby the PUR is softened, or respectively liquefied to a viscosity suitable for provision.
[0050] The heating unit 7 has a second conveying means (not shown here) in the interior. Accordingly, the conveying pressure can be maintained after the change of the viscosity of the PUR. The heated PUR passes through the second outlet 10a through the dosing inlet 10b into the dosing unit 14. FIG. 4 describes the properties of the dosing unit 14. The PUR is pressed up to a longitudinal slit 11, and at that location comes into contact for the first time with the atmosphere surrounding the device. The PUR is then deposited directly onto a rotating roller 13. The components of the device according to FIG. 1 are coated on the inside with an anti-adhesive and chemically highly selective agent.
[0051] FIG. 2 shows the conveyor unit 4 of the device from FIG. 1 with the funnel-shaped reservoir 2 in a section along an axis parallel to the conveying direction. The tubular housing 5 forms a tubular first conveying channel 18 with a diameter K that is dimensioned to receive a screw conveyor 17 with a conveying capacity sufficient to move a desired conveyed amount of PUR. The conveying capacity is approximately 5 kg/h, wherein conveying capacities between 0.5 kg/h and 50 kg/h are preferably moved. The screw conveyor 17 has a rotational direction D such that the PUR is conveyed in the conveying direction F. The particulate PUR passes in the entry direction E through the first inlet 3 into the first conveying channel and is conveyed through the entire length L1 of the conveyor unit up to the first outlet 6. Alternatively, instead of a screw conveyor, an extruder can be used that is more suitable for the buildup of high conveying pressures. The conveying pressure is approximately 5 bar, wherein preferred conveying pressures lie between 0.1 bar and 50 bar, particularly preferably between 1 bar and 30 bar, and most preferably between 2 bar and 8 bar.
[0052] FIG. 3 shows an outside view of the heating unit 7. In the interior, the tubular housing 8 forms a second conveying channel (not shown here) with the channel diameter K and the length L2. Arranged around the housing 8 in this case are two separate heating coils 19, 20. The heating coils 19, 20 each consist of a continuous heating line 21 that is produced as a resistance wire from an iron/chromium/aluminum alloy and is electrically conductive. The heating coils 19, 20 correspondingly function as resistance heaters. The PUR is conveyed in the heating unit 7 under the conveying pressure and by the second conveying capacity of a second conveying means (not shown here) in the interior of the heating unit 7 from a second inlet 9 to a second outlet 10a along the conveying direction F. The first heating coil 19 has a tighter winding than the second heating coil 20. Accordingly, the input of thermal energy into the PUR at the beginning is locally greater. The PUR arrives in a solid and cool state; consequently a high temperature gradient promotes efficient and rapid heating. The heating coils 19, 20 are separately regulatable by a regulation unit (not shown here) so that the second heating coil 20 with the other winding can finely adjust the PUR to approximately a precise target processing temperature over a longer path and period. The heating coils 19, 20 heat the PUR up to approximately 140° C., wherein alternatively processing temperatures between 15° C. and 250° C. can be exactly generated.
[0053] FIG. 4 shows the dosing unit 14 of the device according to the invention with an associated roller 13 on which the PUR is deposited onto the roller surface 26 from the longitudinal slit 11. The roller 13 rotates about the rotational axis A in the rotational direction R, wherein the roller 13 is driven by an electric motor (not shown here). The longitudinal slit 11 is formed in the example according to FIG. 5a as a stripped-shaped cutout in the side of the dosing unit facing the roller 13. Alternatively, FIG. 5b shows a biconcave design of the longitudinal slit so that less PUR is deposited in the middle of the longitudinal slit 11 than at the edge regions to save adhesive. In this case, the longitudinal slit has a maximum width B2 at the edge regions and a minimal width B1 in the middle. The PUR passes through the dosing inlet 10b (not shown here) into the dosing unit 14. The dosing inlet 10b in this case lies behind the image plane, just like a tubular third conveying channel that ends in the distribution chamber 30. The distribution chamber 30 is a hole in the block-like housing 15 that widens the cross-section of the third conveying channel up to that of the longitudinal slit 11. The path of the third conveying channel is meandering so that the PUR has a longer dwell time in the block-like housing 15 through which heating channels 22 run. The energy introduced by the heating channels 22 in the form of heat provides for the exact, fine adjustment of the provision temperature of the PUR that lies at about 150° C. The provision temperature should be reached by the PUR before it is finally pressed out of the longitudinal slit 11 and is deposited onto the roller surface 26.
[0054] A longitudinal adjustment 23 is upstream from the longitudinal slit 11. This is a continuous hole into which an adjustment element can be introduced from one or from both sides, and accordingly the PUR can be directed to the unsealed regions of the longitudinal slit 11 instead of applying PUR to the entire thing. An adjustment element is not shown in greater detail in this case, but it can however for example be a bolt or a pin consisting of various minimally adhesive material. The roller 13 is a cylindrical body with two end surfaces spaced by the length of the roller 13. A potential design of the roller 13 is explained further in FIG. 7. The roller is made from a piece of aluminum, wherein the surface has a relief-like pattern (not shown here). The roller 13 has a roller heater 27. Thermal oil flows therethrough so that the temperature of the PUR on the roller 13 can be kept constant. In a preferred embodiment, the roller heater 27 can be realized as a heating channel, or by electrically heated heating rods. Analogously, the heating channels 22 can also be replaced by electrically heated heating rods. These ensure that the exact processing temperature of the PUR at the longitudinal slit 11 is reached. Correspondingly, the temperature of the heating channels 22 and the roller heater 27 can be regulated to a target value.
[0055] A scraper 28 assigned to the roller 13 ensures that the PUR deposited on the roller surface 26 has a homogeneous thickness viewed over the perimeter of the roller before the PUR is applied to a workpiece introduced from the thrust direction S. The scraper is made of aluminum. The material is relatively cheap, light, chemically selective and also has high strength in addition to being easily machinable.
[0056] FIG. 5a especially illustrates the design of the longitudinal slit 11. The length L of the longitudinal slit is greater by a ratio of 20:1 in comparison to its width B. Preferably, such a ratio lies between 5:1 and 100:1, particularly preferably 15:1 to 60:1. Correspondingly, the longitudinal slit 11 is always elongated, for example strip-shaped as in this case. The width B is adjustable by a control valve 29, or respectively the longitudinal slit 11 can be closed when the control valve 29 is in an end position. The control valve 29 has for example two adjusted positions so that the slit width can be discontinuously selected between narrow and wide, and the PUR flow, inter alia, can be thereby controlled. A narrow longitudinal slit 11 is easily covered by a diaphragm that is part of the maximum slit width. In alternative embodiments, a control valve 29 can be designed with continuously adjustable adjusted positions that can also control different slit widths.
[0057] In another alternative embodiment according to FIG. 5c, the control valve 29 is used to offer an alternative option for longitudinal adjustment. The adjustment is not performed by adjusting elements that can be inserted by the ends (see FIG. 4), but rather by a diaphragm 35 that can be screwed in in rotational direction D2, wherein the diaphragm 35 has a (bi)convex design. Accordingly, the longitudinal slit 11 is first covered at the edge regions, and as the diaphragm is increasingly screwed in at the end position, is also covered up to the middle from the inside. The principle can for example also be realized by a ball valve with an oval flow bore. In an alternative embodiment, the longitudinal adjustment 23 can also be designed with a concave diaphragm and can therefore cover the longitudinal slit 11 successively from the middle to the end regions upon being screwed in further.
[0058] FIG. 6 shows a preferred embodiment of the device according to the invention for providing adhesive with a coloring device 34 for applying a colored substance to the roller 13. Alternatively, a binder or a second adhesive can also be applied in this manner. The coloring device 34 consists of a mixing reservoir 31, a feedline 32 and a color outlet 33. The mixing reservoir 31 contains several separate reservoirs of basic colors, and a controllable means for mixing these basic colors into a desired application color. The components of the coloring device 34 are made of aluminum and are arranged in this case so that the color can be applied directly onto the roller 13 together with the provision of the adhesive. The color application C is effected to the edge regions P of the PUR layer deposited on the roller surface 26. The resulting distance according to FIG. 6 between the color application C and the edge region P of the PUR layer is purely illustrative. In practice, contact is also possible. FIG. 6 moreover illustrates that the PUR layer can also be only over parts of the height H of the roller depending on the longitudinal adjustment of the longitudinal slit (not shown here).
[0059] FIG. 7 shows a design of the roller 13, wherein heating elements mentioned above that the roller 13 can possess are not shown for the sake of clarity. A shaft 36 extends from a drive (not shown here) to a driver 37 that is mounted on the free end 38 of the shaft 36 which is not clamped in the drive. The shaft 36, and therefore the roller 13, extend generally vertically upward since the workpiece (not shown) to be coated is guided past the side of the roller 13. The driver 37 is provided with a groove 39. The shaft 36 is enclosed by a holder 40 close to the drive. The holder 40 can be provided with a top part of a hinge (not shown here). The guide 41 that does not rotate with the shaft 36 during operation is mounted on the holder 40. The guide 41 is designed as a sleeve that is arranged concentric to the shaft 36 and encloses it. The guide 41 extends mainly from the holder 40 to the driver 37. At least one slide bearing 42 is arranged on the outside of the guide; in FIG. 7, the preferred arrangement with two slide bearings 42 is shown, wherein a first slide bearing 42 is arranged near the holder 40, and a second slide bearing 42 is attached near the free end of the 38 of shaft 36.
[0060] A roller sleeve 43 whose inner diameter is dimensioned such that the roller sleeve can be shoved over the guide 41 is also shown in FIG. 7. A handle 44 is on the roller sleeve 43 along with a bearing 45, in this case designed as a ball bearing, that can optionally be fastened to the dosing unit 14 (not shown here). To clean the device, or when changing an adhesive, or when changing the workpiece to be coated, it may be necessary to change the roller. In the present case, only the roller sleeve 43 needs to be removed and a new roller sleeve 43 mounted. The other components of the roller 13 can remain in the device. Removing the entire roller 13 is therefore avoided. It is obvious that this design is very service-friendly since only the roller sleeve 43, or respectively its outer surface needs to be cleaned without having to take into account the guide 41, or the shaft 36, or respectively the drive. More-over, only one drive, one shaft 36 and one guide 41 are needed. Only several roller sleeves 43 must be kept available, which makes this design economical and efficient to operate.
[0061] The roller sleeve 43 has an opening 46 which is penetrated by a set screw 47. The set screw 47 engages with the groove 39 during operation and causes the shaft 36 to also set the roller sleeve 43 in rotation. The outer surface 48 of the rotating roller sleeve 43 takes the adhesive from the dosing unit 14 and then transfers it within a path that is shorter than one rotation of the roller 13 to the narrow surface of the workpiece to be coated (not shown here).
[0062] FIG. 8 shows a roller 13 according to FIG. 7 that has on its handle 44 a latch 49 attached to the dosing unit 14 (not shown here). The latch is designed as a simple hook which is placed over a projection that is attached to the handle 44 of the roller 13. FIG. 9 shows the dosing unit 14 with the roller 13 attached thereto. The drive 50 of the roller 13 is fixed to the dosing unit 14. A means, in this case designed as a hinge 51, is arranged between the drive 50 and roller 13 for swinging, or respectively pivoting the roller 13. The hinge 51 makes it possible to swing away, or respectively pivot the roller 13 relative to the dosing unit 14 when the latch 49 is opened. The longitudinal slit 11 of the dosing unit 14 is freely accessible when the roller 13 is swung away, or respectively pivoted, for example for cleaning tasks or to close the longitudinal slit 11. Alternatively, the roller 13, if applicable also with the drive 50, can also be equipped to be linearly shiftable, for example vertically shiftable. According to another embodiment, the roller 13 can also be designed for a combined movement, for example, first a shifting, and then a swinging or pivoting.
TABLE-US-00001 List of Reference Signs 1 Device for providing adhesive 2 Reservoir 3 First inlet 4 Conveyor unit 5 First housing 6 First outlet 7 Heating unit 8 Second housing 9 Second inlet 10a Second outlet 10b Dosing inlet 11 Longitudinal slit 12 Ball valve 13 Roller 14 Dosing unit 15 Third housing 17 Screw conveyor 18 First conveying channel 19 First heating coil 20 Second heating coil 21 Heating line 22 Heating channel 23 Longitudinal adjustment 26 Roller surface 27 Roller heater 28 Scraper 29 Control valve 30 Distribution chamber 31 Mixing reservoir 32 Feedline 33 Color outlet 34 Coloring device 35 Screwable diaphragm 36 Shaft 37 Driver 38 Free end of the shaft 39 Groove 40 Holder 41 Guide 42 Sliding surface 43 Roller sleeve 44 Handle 45 Bearing 46 Opening 47 Set screw 48 Outer surface 49 Latch 50 Drive 51 Hinge A Rotational axis B Width B1 Minimum width B2 Maximum width C Color application D Rotational direction of a screw conveyor D2 Rotational direction of an oval diaphragm E Entry direction F Conveyance direction K Channel diameter L Length L1 Length of the conveyor unit L2 Length of the heating unit P Edge region of the PUR layer R Rotational direction S Thrust direction
