JPH06198229A - Method and apparatus for applying adhesive - Google Patents

Abstract

PURPOSE: To attain uniform spray applying of an adhesive and to enable automatizing applying work by executing a cleaning process in which a solvent is added to spray air for a short time while interrupting supply of the adhesive during a transition stage from a spraying process to a standstill stage. CONSTITUTION: A method for applying the adhesive has a spraying process in which the adhesive from an adhesive container 71 is atomized by jetting the spray air by using a spray head 13 and is sprayed in a form of conical spray and the standstill stage at which both supply of the adhesive and supply of the spray air are interrupted. During the transition stage from the spraying process to the standstill stage, the cleaning process, in which the solvent for the adhesive is added to the spray air from a solvent container 91 at least for a short time while interrupting supply of the adhesive, is executed. Consequently the solvent added to the spray air dissolves and blows off the adhesive stuck to the spray head 13, especially to regions of an adhesive nozzle 41 and a spray air nozzle 55.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive application method and apparatus for spraying an adhesive with a jet of spray air by using a spray head and spraying the adhesive in the form of a conical spray.

[0002]

BACKGROUND OF THE INVENTION In many applications, adhesives must be applied to a wide range of surfaces as evenly as possible, and even to specially contoured surfaces. For example, in the manufacture of shoes, in order to bond the sole, the adhesive must be applied to the bottom of the shoe very accurately. This is because a sufficient amount of adhesive must be applied to fill the outer peripheral surface of the bottom surface of the shoe, but the adhesive must not reach the upper of the shoe. To that end, in addition to the above-mentioned requirement that the application of adhesive must be very precisely restricted to specific areas, there is a clear distinction between adhesive-coated and uncoated surfaces. It is necessary to define boundaries or boundaries.

Application of the adhesive to the required surface of the workpiece, in particular the bottom surface of the shoe, by spraying has already been tried in practice. In this spray method, the adhesive ejected from the nozzle is entrained by a jet of compressed air during the adhesive spraying process, stirred, and applied to the bottom surface of the shoe. If the nozzle for ejecting the adhesive and the nozzle for ejecting the compressed air are designed in harmony, the jet of compressed air is defined in a relatively clear shape and is disturbed (turbulent). Into droplets of adhesive, forming a cone-shaped spray. This cone spray is moved over the surface to be applied once or several times to apply the required thickness of adhesive layer. The achievable accuracy of the contour of the adhesive surface (adhesive-coated surface) corresponds approximately to that of the cone spray. Here, the “adhesive surface” refers to the surface to which the adhesive is applied or the surface to which the adhesive is applied.

After the adhesive has been applied to the adhesive surface, a conical spray so that the work piece can be replaced (the work piece with the adhesive application can be transferred and the next work piece can be carried in). To stop. Therefore, the adhesive spray device operates intermittently with some rest phases.

The distribution and number of adhesive droplets in the jet of compressed air, and the cross-sectional area of the jet of compressed air,
Therefore, the shape of the spray adhesive spot formed on the surface to be coated depends on the shape and condition of the compressed air nozzle and the adhesive nozzle and the parts arranged in the vicinity of these nozzles. For example, the adhesive deposited in those nozzles may change the shape of the cone spray to such an extent that it causes an uneven distribution of adhesive droplets in the cone spray. As a result, the shape of the adhesive surface is changed, and the thickness of the adhesive layer is made uneven, especially near the periphery of the adhesive surface.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an adhesive application method which makes it possible to form an adhesive surface having constant and well-defined boundaries, and an adhesive application apparatus for carrying out the method. Is to provide.

[0007]

In order to solve the above-mentioned problems, the present invention comprises a spraying step of atomizing an adhesive with a jet of spray air using a spray head and spraying it in the form of a conical spray. In an adhesive application method having a pause step in which both the supply of adhesive and the supply of spray air are interrupted, during the transition step from the spraying step to the pause step, the adhesive supply is interrupted while the supply of adhesive is interrupted. Provided is a method for applying an adhesive, which comprises performing a cleaning step of adding a solvent to spray air for at least a short time.

In the cleaning step immediately following the spraying step, the solvent added to the compressed air dissolves the adhesive adhering to the spray head, in particular the area of its nozzles (adhesive nozzle and spray air nozzle). The solution in which the adhesive is dissolved in this way has high fluidity and is blown off by a jet of spray air. After the cleaning process is complete, the spray head is kept degreased for a long time during the next rest phase. When the spraying process is restarted, the spray air and adhesive dry or solidified adhesive are ejected through a clean nozzle free of deposits. Thus, the conical spray takes its intended shape and the homogeneity of the adhesive droplet distribution in the conical spray is not disturbed. Regardless of the mode of operation of the spray head, i.e. regardless of the ratio of the length of time of the spraying process to the length of time of the rest phase, a constant conical spray is obtained, and therefore a uniform adhesive spray is obtained. Spray application is achieved. Thus, it is possible, for example, to automate the coating operation by mounting the spray head on a robot arm which moves in a predetermined sequence with respect to a particular workpiece.

By carrying out the washing step after each spraying step, a good and even cleaning action is achieved, so that a constant conical spray is obtained. When an aqueous PU adhesive is used as the adhesive and water is used as the solvent, it is possible to substantially avoid the vapor load on the ambient air that is harmful or toxic to human health. If the spray air supply is interrupted and the solvent is supplied instead during the cleaning process, the cleaning process can be performed without the need to connect an additional conduit for solvent to the spray head. The effect is obtained. The addition of solvent to the spray air can be done easily in three steps. That is, in the first and first stage of the cleaning process, only the spray air is supplied to blow off the relatively coarse residual adhesive mass,
Then, in the second stage, the supply of the spray air is interrupted to supply the solvent to the spray air conduit under pressure, and in the final third stage, the spray air is supplied again for a short time to remove the solvent (eg
Residual adhesive can be removed substantially completely by discharging (water) with the spray air in a disturbed state.
When the time required for the first step and the time required for the second step are substantially equal to each other and the time required for the second step is substantially one fifth of the time required for the first step, a good cleaning effect is obtained. . In that case, it is sufficient to set the time required for the first stage to approximately 0.5 seconds.

The method of the invention is suitable for use in applying an adhesive to the bottom of shoes in the manufacture of shoes. If the adhesive is applied in a direction perpendicular to the bottom of the shoe during the spraying process, it is easy to control the transition from the adhesive sprayed surface to the unsprayed surface. If the adhesive is sprayed starting from the center of the front of the shoe sole and along the periphery of the sole, the cone spray that forms first stabilizes at the center of the shoe sole, thus forming a cone spray. The process transitions do not adversely affect the quality of the adhesive coating (marginal contours and uniform thickness).

Advantageously, the cleaning step is carried out by holding the spray head above a central region remote from the periphery of the bottom of the shoe. The solvent spots that splatter on the bottom of the shoe during the cleaning process will dry on the bottom of the shoe without compromising the sharply defined contours of the previously sprayed adhesive coating.

In order to solve the above problems, the present invention also comprises a spray head having an adhesive connection port and a spray air connection port connected to a spray air conduit for carrying out the above method. In the adhesive application device, a spray pressure conduit that connects the spray air conduit to a compressed air supply source, or a switch for selectively connecting to a solvent supply source is connected to the spray air conduit. Provided is an adhesive coating device. The spray air conduit is connected to a controllable switch that can selectively connect the conduit to a compressed air source or a solvent source so that solvent can be supplied directly to the spray air conduit.

Advantageously, the spray head is provided with a needle valve for regulating and controlling the supply of adhesive. This avoids dripping or sticking of the adhesive during the closing of the needle valve. If the supply device is shut off by a needle valve provided with a spring-loaded needle valve element in the valve closed position, it is possible to prevent the adhesive agent from spouting. Furthermore, this needle valve
It can be connected to a piston, which is hermetically housed in a chamber provided with a connection opening for receiving compressed air and is movable in the longitudinal direction of the needle valve. This piston is
A simple pneumatic drive means for driving the needle valve is constructed.

The amount of adhesive ejected, and thus the thickness of the adhesive coating produced, is controlled by the adhesive discharge adjusting screw disposed on the axial extension of the needle valve to open the needle valve. It can be made adjustable by controlling the movement stroke towards the position.

The rapid introduction of the solvent into the spray air conduit is effected by the above-mentioned diverter, which preferably has both an electromagnetically actuated compressed air valve and a solvent valve. 3/2
By using the directional control valve, it is possible to release the pressure at the inactivated one of the two inlets of the two-way valve (two-way opening / closing valve) connected to the outlet side thereof. Thus, the switching operation in these two directions can be performed quickly and stably. The compressed air does not enter the area of the solvent and, for example, the solvent does not enter the spray air during the spraying process.

[0016]

1 shows a five-axis robot consisting of a fixed column 3 and a movable part 2 mounted on it. The movable part 2 is mounted on the column 3 rotatably about a vertical axis 4 and comprises an arm 6 pivotable up and down about a horizontal axis 5. The arm 6 consists of two links which are pivotable about an axis 7 parallel to the axis 5 at approximately its midpoint. At the outer end of the arm 6 on the side remote from the column 3, a holder 9 is attached, which is pivotable around an axis 8 parallel to the axes 5 and 7, and a tool carrier 11 is rotatably carried by the holder 9. Has been done. The tool carrier 11 is rotatable about an axis 12 that is perpendicular to the axis 8.

The pivoting or rotary movement about each axis 4, 5, 7, 8 and 12 is carried out by respective drive means, for example a hydraulic motor or an electric motor. These drive means are controlled by the control unit so that the tool carrier 11 makes the necessary movements.

A spray head 13 for spraying a water-soluble adhesive, preferably a PU-based adhesive, onto the corresponding surface 15 of the workpiece 16 in the form of a conical spray is fixed to the tool carrier 11. In the illustrated embodiment, the workpiece 16
Is a shoe and the surface 15 is the bottom of the shoe. The shoe 16 is put on a shoe mold and tightened. Sole is the bottom of the shoe 15
Adhesive must be applied to the bottom surface 15 prior to bonding to. The bottom surface 15 of the shoe is not flat because it has a curvature that matches the shape of the shoe (and thus the finished shape of the shoe 16). The adhesive must be applied to the bottom surface 15 of the shoe up to its rim 17, but not to the upper of the shoe.

The shoe 16 which is placed on the shoe last is held in place by a clamp consisting of, for example, four clamping jaws 18 schematically illustrated in FIG. The allowable range of displacement of the shoe holding position is at most 0.5 mm.

The peripheral edge 1 of the bottom surface 15 of the shoe during the application of the adhesive.
The spray head 13 guided along 7 is shown in longitudinal section in FIG. Longitudinal axis or spray axis 2
The spray head 13, which is rotationally symmetrical with respect to 1, comprises a substantially cylindrical valve body 22 and the components carried on it. The valve body 22 has cylindrical bores 23, 24 of approximately the same diameter formed coaxially with respect to the spray axis 21 at both ends, i.e. at the top and bottom as seen in FIG. Each inner hole 23, 24 has a flat bottom wall 25, 26.
The inner holes 23 and 24 are connected by a guide hole 27. The needle valve 28 has a diameter corresponding to the cylindrical shaft portion 29 of the needle valve element 28, receives the shaft portion slidably in the vertical direction, and guides the vertical movement of the shaft portion. In order to seal the shaft portion 29 from the valve body 22, an annular groove 32 is cut in the wall of the guide hole 27, and an O-ring seal 31 is attached to these grooves.

A piston 34 in the form of a disk-shaped head that is vertically movably received in the inner hole 23 is connected to one end of the shaft portion 29 of the needle valve element 28. An annular groove 35 is cut on the outer peripheral surface of the piston 34, and an O-ring seal 36 is attached to the groove. Thus, the piston 34 is received axially movably in a sealed manner within the bore 23 and opens and closes a chamber 37 having a connection port 38 for receiving compressed air.

The needle valve element 28 has a tapered conical valve member 39 protruding from the inner hole 24 at the other end. A conical adhesive nozzle 41 having a circular adhesive injection port 42 is provided coaxially with the conical valve member 39. The adhesive nozzle 41 is screwed into an internal thread 43 formed on the wall of the inner hole, and the annular shoulder portion 44 of the nozzle is brought into contact with the edge of the inner hole 24. The inner diameter of the adhesive nozzle 41 is gradually reduced toward the adhesive injection port 42. The size of this inner diameter is determined by the piston 34 being displaced axially back and forth (up and down as viewed in FIG. 2) in the inner hole 23 so that the adhesive injection port 42 is opened and closed by the valve member 39 of the needle valve element 28. Is determined. Adhesive nozzle 41 and bore 24 define an adhesive chamber 45. Adhesive is supplied to the adhesive chamber 45 through the adhesive connection port 46 at a constant pressure of 1 to 1.5 bar.

When the needle valve 28 is displaced upward as viewed in FIG. 2, the injection port 42 of the adhesive nozzle 41 is opened, and the width of the annular gap between the conical valve member 39 and the injection port 42 is reduced to the needle valve valve. Two
8 gradually increases with upward displacement. In order to enable setting of the width of the annular gap, and thus the amount of adhesive ejected per unit time at a predetermined pressure, an adhesive discharge amount adjusting screw 48 is provided with a holding member 49 screwed to the valve body 22. It is screwed into it as an adjustable stopper for the piston 34 and abuts against the end face of the piston 34. A knurled head is connected to an end portion of the adhesive discharge amount adjusting screw 48 protruding from the holding member 49 to facilitate manual adjustment of the adhesive discharge amount. The holding member 49 for receiving the adhesive discharge amount adjusting screw 48 has a coaxial threaded inner hole 51, and the threaded inner hole 51 is formed into a large diameter inner hole 52 on the side facing the piston 34. linked. A coil spring 53 is housed in the large-diameter inner hole 52, one end of the spring 53 abuts on the bottom wall of the inner hole 52, and the other end abuts on the end surface of the piston 34. Thus, needle valve 28 and adhesive nozzle 41 are biased by spring 53 toward the valve closed position.

The valve body 22 has a male screw 54 at the lower end thereof, and a spray air nozzle 55 is screwed onto the male screw coaxially with the spray axis 21. The spray air nozzle 55 is formed in the shape of a cap and has a circular spray air nozzle 56 having a diameter larger than the outer diameter of the adhesive nozzle 41 in the region of the adhesive nozzle 42. The spray air nozzle 56 defines an annular spray air passage coaxial with the adhesive nozzle 42 with the adhesive nozzle 41.
The width of this annular spray air passage is fixed and not adjusted.

The inner diameter of the spray air nozzle 55 is gradually reduced from the valve body 22 toward the spray air nozzle 56. A generally annular spray air chamber 57 is defined between the spray air nozzle 55 and the adhesive nozzle 41.
The spray air is formed in the valve body 22 parallel to the spray axis 21 and is supplied to the spray air chamber 57 through an air channel 58 leading to the spray air connection port 59. The air channel 58 and the spray air chamber 57 are in communication via an annular gap 61 defined by the annular shoulder 44 of the adhesive nozzle 41 and an axial recess formed in the valve body 22. As a result, the pressure distribution in the spray air chamber 57 is made uniform, so that a jet of spray air having a circular cross section is uniformly ejected from the spray air ejection port 56 in the circumferential direction.

The spray head 13 is connected to the supply device 63. The supply device 63 supplies compressed air, adhesive and spray air to the compressed air conduit 64 and the adhesive conduit 65, respectively.
And spray head 13 through spray air conduit 66
To the compressed air connection port 38, the adhesive connection port 46, and the spray air connection port 59. The compressed air conduit 64 is connected to a compressed air distribution conduit 68 via a spring-loaded 3/2 directional control valve 69, which is connected to a compressed air supply 67. When the 3/2 directional control valve 69 is in the rest position, i.e. when the electromagnet of the 3/2 directional control valve 69 is not energized, the pressure (compressed air) is released from the compressed air conduit 64 and thus the chamber 37. .
When the electromagnet of the 3/2 directional control valve 69 is energized to place the 3/2 directional control valve 69 in the actuated position, the compressed air conduit 64
Compressed air distribution conduit 68 via a 3/2 directional control valve 69
And the piston 34 is actuated by the compressed air and is lifted.

An adhesive conduit 65 for supplying adhesive to the adhesive chamber 45 is connected to a sealed adhesive container 71 which holds a large quantity of adhesive ready for supply. A pressure conduit 73 is connected to the top of the adhesive container 71. The pressure conduit 73 is connected to the compressed air distribution conduit 68 via an adjustable pressure reducing valve 74. Thus, above the adhesive supply 72 in the adhesive container 71 is maintained an air cushion 75 which maintains the adhesive under the above-mentioned constant pressure of 1 to 1.5 bar. A pressure gauge 76 is attached to the pressure conduit 73 for checking the pressure of the adhesive that defines the amount of the adhesive ejected when the adhesive ejection port 42 is opened.

The spray air conduit 66 is connected to a water conduit 79 and a spray pressure conduit 80 via a switch 78. The switch 78 includes a two-way valve 81 and two 3 / 2-way control valves 83 and 84. The two-way valve 81 has an outlet 82 that is directly connected to the spray air conduit 66 and two inlets 85 and 86 that are connected to the respective outlets of the 3/2 directional control valves 83 and 84. The inlet having the higher pressure is connected to the outlet 82, and the inlet having the lower pressure is shut off. The 3/2 directional control valves 83 and 84 are both spring-loaded solenoid valves similar to the 3/2 directional control valve 69, and are operated by electromagnets against the return spring. 3/2 directional control valves 69, 83,
Each of the electromagnets 84 is connected to a control device (not shown) that also controls the driving means of the robot arm 6.

The electromagnet of the 3/2 directional control valve 83 (also called "compressed air valve") is de-energized and the 3/2 directional control valve 83 is
2 is placed in the rest position shown in FIG. 2, compressed air is discharged and pressure (air) is released from the inlet 85 of the two-way valve 81. The 3 / 2-way control valve 83 connects the spray pressure conduit 80 to the inlet 85 of the 2-way valve 81 when it is displaced to the right in FIG. . The spray pressure conduit 80 includes an adjustable throttle valve 87 for adjusting the amount of air and an adjustable pressure reducing valve 88.
Connected to the compressed air distribution conduit 68 via. The pressure reducing valve 88 is set to a spray pressure of approximately 3 bar. A pressure gauge 89 is attached to the outlet side of the pressure reducing valve 88.

When the electromagnet of the 3/2 directional control valve 84 (also referred to as the "solvent valve") is de-energized and placed in the rest position shown in FIG. 2, pressure is relieved from the inlet 86 of the two-way valve 81. When the 3/2 directional control valve 84 is displaced to the right as viewed in FIG. Connect to. The water conduit 79 is connected to the outlet of a closed water container 91 that holds the water supply 92 ready for immediate supply. On the liquid surface of the water supply source 92 in the water container 91, an air cushion 93 that maintains a water pressure of 0.5 to 1.5 bar is held. The air cushion 93 is set by compressed air supplied from the compressed air distribution conduit 68 via an adjustable pressure reducing valve 94. The value of this air pressure can be read by a pressure gauge 95 attached to the outlet side of the pressure reducing valve 94.

The operation of the adhesive coating device of the present invention described above is as follows. In order to apply the adhesive to the bottom surface 15 of the shoe 16, the arm 6 of the robot 1 that has been pivoted upward while the shoe 16 is clamped and fixed to the shoe mold is pivoted downward to move the spray head 13 to the shoe 16. Position in the front central region about 20-40 mm above the bottom of the shoe. The spray head 13 is positioned such that its spray axis 21 is perpendicular to the bottom surface 15 of the shoe 16 at a point 96 approximately in the center of the front of the shoe 16, for example. Of course, during this positioning operation, 3/2 of the feeding device 63
The directional control valves 69, 83, 84 are all kept closed. The needle-shaped valve element 28 of the spray head 13 is pressed by the coil spring 54 to the closed position that closes the adhesive injection port 42, and the spray head 13 is placed in the rest stage.

At the start of the adhesive spraying process, first the 3/2 directional control valve 83 is operated to connect the spray pressure conduit 80 under the pressure of 3 bar to the inlet 8 of the 2 directional valve 81.
Connect to 5. The 3/2 directional control valve 84 is kept in a de-energized state to shut off the flow path that connects the water conduit 79 to the inlet 86, so that the pressure at the inlet 86 is released. Therefore, the two-way valve 81 connects one inlet 85 to the spray air conduit 66 and shuts the other inlet 86. Thus, the spray air jet is ejected from the spray air jet port 56 of the spray head 13, and the spray air jet becomes a clear conical shape in several tens of milliseconds, and is stabilized in this state.

After about 0.5 seconds, the blowing process is started by introducing compressed air into the chamber 37 through the compressed air conduit 64. For this purpose, the 3/2 directional control valve 69 is actuated, opening the flow path for full pressure compressed air from the compressed air distribution conduit 68. Compressed air immediately
The piston 34 is pushed up until it comes into contact with the stopper formed by the end face of the adhesive discharge amount adjusting screw 48, thereby lifting the needle valve 28 and opening the adhesive injection port 42. Thus, the adhesive ejected from the adhesive ejection port 42 at the above-mentioned pressure of 1 to 1.5 bar from the ejection port 42 is entrained by the spray air jet ejected from the spray air ejection port 56, disturbed and crushed into droplets, Evenly distributed in the spray air jet. In this way, the conical spray 14 is formed. The opening of the adhesive jet 42 and the addition of adhesive to the spray air jet will initially cause some turbulence in the spray air jet, but the conical spray 14 will soon stabilize automatically. , The shape becomes constant (no change, stable). This stabilization process is performed in the center of the front part of the shoe 16.
That is, since it occurs relatively far from the periphery 17 of the bottom surface 15 of the shoe, the short-term fluctuations or deformations that occur in the conical spray 14 are the quality of the adhesive coating (a well-defined contour and a uniform thickness). Does not interfere with.

When the conical spray 14 becomes stable and has a constant shape, the robot arm 6 operates the spray head 13 to move the spray head 13 on the bottom surface 15 of the shoe. In that case, the spray head 13 is always moved along the path 97 so that the outer edge of the conical spray 14 fits exactly around the periphery 17 of the bottom surface 15 of the shoe, but never over the periphery 17. The spray axis 21 of the spray head 13 is held perpendicular to the bottom surface 15 of the shoe at any time during the movement of the spray head. The spray head 13 is guided at a constant speed along the entire periphery 17 of the bottom surface 15 of the shoe, and the adhesive is sprayed from about 20-40 mm above the bottom surface 15 of the shoe as described above. The spray head 13 is guided with a positioning accuracy with an error of less than 0.5 mm.

Once the spray head 13 has moved along the entire periphery 17 of the bottom surface 15 of the shoe and the adhesive has been applied to the bottom surface 15 of the shoe, the spraying process is terminated and the adhesive nozzle 41 and the spray air nozzle. A cleaning process is started to remove residual adhesive adhering to 55. Spray head 1
The 3/2 directional control valve 69 is switched to its rest position with 3 still centered away from near the periphery 17 of the bottom surface 15 of the shoe. Thereby, the air pressure is released from the chamber 37, and the spring 53 pushes down the piston 34. As a result, the conical valve member 39 of the needle-shaped valve element 28 causes the adhesive injection port 4 to move.
Close 2 The blast of spray air is continued by maintaining the 3/2 directional control valve 83 for spray air in operation for about 0.5 seconds after the start of the cleaning process, thereby causing a relatively coarse residual adhesive mass. Blow away.

After about 0.5 seconds, the 3/2 directional control valve 83 for spray air is closed for 0.1 seconds. In the meantime, the 3/2 directional control valve 84 for water introduction is opened for a few milliseconds to bring the water source 92 under pressure from the water conduits 79 and 2.
A few drops of water (solvent for adhesive) are introduced into the spray air conduit 66 through the directional valve 81. After the lapse of the time of 0.1 seconds, the 3/2 directional control valve 83 for spray air is again set to 0.5 with the 3/2 directional control valve 84 closed.
Open for seconds. Thus, the spray air at a pressure of 3 bar disturbs the water in the spray air conduit 66 (and also the water if it is already present in the spray air chamber 57), 3 / for the spray air. 2-way control valve 8
Rinse the liquid residual adhesive until 3 is closed. During the washing process, water (solvent) is scattered in the central area of the bottom surface of the shoe to form a water spot, which is dried in a few minutes.

After the cleaning process is completed, the spray head 1
3 is put in the dormant phase again. Spray head 13
Does not clog with residual adhesive for long periods during the rest phase. As described above, when the residual adhesive accumulated during the spraying process adheres to the inside of the adhesive nozzle 41 and the spray air nozzle 55 of the spray head 13, it affects the cross-sectional area of the nozzle and thus the cross-sectional shape of the conical spray. However, according to the present invention, the residual adhesive is removed in the cleaning process.

Although the present invention has been described with reference to the embodiments, the present invention is not limited to the structures and modes of the embodiments illustrated herein, and deviates from the spirit and scope of the present invention. It should be understood that various embodiments are possible and that various changes and modifications can be made.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of an adhesive application device for applying an adhesive in the manufacture of shoes.

FIG. 2 is a schematic view of an adhesive application device for carrying out the method of the present invention, showing the spray head in cross-section.

[Explanation of symbols]

 13: Spray Head 14: Conical Spray 15: Bottom 16: Shoes 17: Periphery 28: Needle Valve 29: Shaft 34: Piston 37: Chamber 38: Compressed Air Connection Port 39: Conical Valve Member 41: Adhesive Nozzle 42: Adhesive injection nozzle 48: Adhesive discharge amount adjusting screw 55: Spray air nozzle 56: Spray air injection nozzle 63: Supply device 66: Spray air conduit 67: Compressed air supply source 69: 3/2 direction control valve 71: Adhesion Agent container 72: Adhesive supply source 78: Switching device 80: Spray pressure conduit 81: Two-way valve 83: Compressed air valve (3/2 direction control valve) 84: Solvent valve (3/2 direction control valve) 91: Water (Solvent) container 92: Water (solvent) supply source

Claims (21)

[Claims] 1. A spraying process in which a spray head is used to atomize the adhesive with a jet of spray air and spray it in the form of a conical spray, and a pause step in which both the supply of adhesive and the supply of spray air are interrupted. In the adhesive applying method having, during the transition step from the spraying step to the resting step, a cleaning step of adding a solvent for the adhesive to the spray air for at least a short time while interrupting the supply of the adhesive. A method for applying an adhesive, which is performed. 2. The adhesive application method according to claim 1, wherein the cleaning step is performed after each spraying step. 3. A water-based PU adhesive is used as the adhesive,
Water is used as the solvent.
The method for applying an adhesive according to. 4. The adhesive application method according to claim 1, wherein during the cleaning step, the supply of spray air is interrupted and a solvent is supplied instead of the spray air. 5. The cleaning process comprises the step of supplying only spray air to remove the adhesive, and interrupting the supply of spray air to supply solvent to the supply conduit for spray air under pressure. The adhesive application method according to claim 1, further comprising a second step of performing a solvent and a third step of stopping the supply of the solvent and supplying spray air to remove the adhesive. 6. The adhesive application method according to claim 5, wherein the time required for the first step and the time required for the third step are substantially equal. 7. The time required for the second step is approximately one fifth of the time required for the first step.
The method for applying an adhesive according to. 8. The method of applying an adhesive according to claim 5, wherein the first step lasts for approximately 0.5 seconds. 9. The adhesive application method according to claim 1, which is applied to apply an adhesive to the bottom surface (15) of a shoe in the production of shoes. 10. The method of applying an adhesive according to claim 9, wherein in the spraying step, the adhesive is sprayed vertically to the bottom surface (15) of the shoe. 11. Adhesion according to claim 9, characterized in that in the spraying step the spraying of the adhesive is started from the central part of the front part of the bottom surface (15) of the shoe and along the periphery of said bottom surface. Agent application method. 12. The adhesive application according to claim 9, wherein the cleaning step is performed by placing the spray head (13) on a central portion of the bottom surface of the shoe, which is separated from the periphery of the bottom surface (15). Method. 13. Adhesion for carrying out the method according to claim 1, comprising a spray head having an adhesive connection and a spray air connection connected to a spray air conduit. In the agent applying device, the spray air conduit (66) is connected to a compressed air supply source (6).
A spray pressure conduit (80) leading to 7) or a switch (78) for selectively connecting to a solvent supply (91) is connected to the spray air conduit (66). Adhesive coating device. 14. The adhesive application device according to claim 13, wherein the spray head includes a needle valve for adjusting and controlling the supply of the adhesive. 15. The adhesive applicator according to claim 14, wherein the needle valve has a needle valve element (28) spring-loaded in a direction of closing the needle valve. 16. A chamber (3) with a needle (28) having a connection (38) for receiving compressed air.
15. Adhesive application device according to claim 14, characterized in that it is connected to a piston (34) housed in 7) in a hermetically sealed manner in the longitudinal direction of the needle valve element. 17. A stroke for moving the piston toward the needle valve opening position is defined by an adhesive discharge amount adjusting screw (48) arranged on an extension line in the axial direction of the needle valve (28). The adhesive application device according to claim 16, wherein: 18. The adhesive applicator of claim 13, wherein the switch (78) includes a compressed air valve (83) and a solvent valve (84). 19. Adhesive applicator according to claim 18, characterized in that the compressed air valve (83) and the solvent valve (84) are 3/2 directional control valves. 20. The adhesive application device according to claim 18, wherein outlet sides of the compressed air valve (83) and the solvent valve (84) are connected to a two-way valve (81). 21. The spray air conduit (66) leading to the spray head on the outlet side of the two-way valve (81).
The adhesive application device according to claim 20, wherein the adhesive application device is connected to.