JPS6144545B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an automatic method in which a spray gun that reciprocates in a direction substantially perpendicular to the direction of conveyance coats a workpiece conveyed in one direction by a conveyance device such as a conveyor. The present invention relates to a coating method and apparatus, and particularly relates to an automatic coating method and apparatus that can coat an object with a uniform thickness even when the conveyance speed of the object to be coated is changed.

For example, when applying anti-rust paint to the surface of a steel plate that is conveyed in one direction on a conveyor, the first and second
As shown in the figure, an endless chain c that circulates in a direction perpendicular to the conveyance direction of the steel plate a is arranged above the conveyor b, and a sliding guide d that is connected to the endless chain c and crosses the conveyor b at right angles. A downward spray gun f is attached to a carriage e that reciprocates, and the paint is sprayed while the spray gun f is reciprocated at right angles to the conveying direction of the steel sheet a, thereby continuously coating the steel sheet a. Generally, an automatic coating device with a different structure is used, and as shown in FIG. a forward stroke L1 tilted at a constant angle determined by combining the motion speeds of the spray gun f;
A backward stroke L2 inclined in the opposite direction at the same angle, and a substantially semi-elliptical turning stroke L3 in which the semicircular locus drawn by the spray gun f at the turning parts on both sides of the endless chain c is extended in the conveying direction of the steel plate a. It has a zig-jig shape. At this time, if the paint is injected only in the forward stroke L1, and the pitch in the direction perpendicular to the forward stroke L1 is made to match the spray width W of the paint, as shown in FIG. Furthermore, there is no uncoated area, and the coating is uniformly applied once by the continuous coating band g. However, in reality, the density of the paint is low at both edges of the coating strip g, resulting in a thin coating film, so both edges of the coating strip g should overlap slightly, but in this specification, the spray width The following discussion assumes that the density of the paint is constant over the entire W and that a uniform film thickness can be obtained. However, if the conveyance speed of the steel plate a is increased without changing the motion speed of the spray gun f, the inclination angle of the forward stroke L1 and the backward stroke L2 of the trajectory L increases, as shown in FIG. , since the turning stroke L3 is stretched in the conveying direction of the steel plate a and the pitch of the forward stroke L1 is expanded, if the paint spraying width W is the same as the example in FIG. This causes unpainted areas, and the backward stroke L2
Even if the paint is sprayed, there will be areas that have been coated once and areas that have been coated twice, resulting in uneven coating. In this case, unpainted areas can be prevented by enlarging the coating width W, but changing the coating width W requires replacing the nozzle, which not only makes setup changes complicated;
Since the coating width W is changed in stages by changing the nozzle, there is a drawback that fine adjustment is not possible. On the other hand, the spray gun f is proportional to the conveying speed of the steel plate a.
If the speed of movement of spray gun f is increased, it is possible to maintain the trajectory L of spray gun f in the state shown in Figure 5 and achieve uniform coating. In order to prevent this, it is necessary to replace the nozzle with a larger discharge amount, which results in the same drawbacks as mentioned above.

An object of the present invention is to provide an automatic painting method and apparatus that can solve these drawbacks all at once.

Hereinafter, an example of the apparatus of the present invention will be explained based on FIGS. 3 and 4, and an example of the method of the present invention will be clarified in the explanation of its operation.

In the figure, 1 indicates horizontal frames 2, 2 on both the left and right sides.
The conveyor is a conveyor in which a large number of rollers 3 are rotatably supported at equal intervals between them, and two sprockets 4, 4 are attached to every two rollers 3, and a chain 5 is installed between each sprocket 4, 4. The chain 5 at the end is connected to a variable speed motor (not shown) attached to the horizontal frame 2.
By driving this motor, the rollers 3 to which the sprockets 4, 4 are attached rotate at the same speed, so that the steel plate a, which has been brought in from the right side in the figure, is conveyed to the left side in the figure. Also, sprockets 4, 4
A small sprocket 6 is attached to the roller 3 (the rightmost roller in the figure), and a chain 10 is stretched between this sprocket 6 and a sprocket 9 attached to the input shaft 8 of the pulse transmitter 7. The input shaft 8 rotates at a speed proportional to the speed of the roller 3, and one pulse is emitted from the pulse transmitter 7 each time the input shaft 8 rotates by a certain angle. Vertical frames 11, 11 are provided opposite to each other on the outside of the horizontal frames 2, 2, and two guide bars 12, 12, which are perpendicular to the conveying direction of the conveyor 1, are spaced apart from each other in the horizontal direction. A spray gun 14 is mounted downward on a carriage 13 which is slidably supported by both guide bars 12, 12. A variable hydraulic motor 15 is attached to the outer surface of the vertical frame 11 on one side, and a bracket 18 that projects upward from the conveyor 1 is attached to the inner surface of the vertical frame 11.
A sprocket 20 is attached to a shaft 19 which is rotatably supported by this bracket 18.
and a sprocket 17 attached to the output shaft 16 of the variable hydraulic motor 15, and a chain 21 passing through a window hole 11a provided in the vertical frame 11. A driven sprocket 2 is attached to a bracket 22 protruding from the inner surface of the vertical frame 11 on the other side.
3 is rotatably supported, and an endless chain 25 is stretched between this driven sprocket 23 and a drive sprocket 24 attached to the shaft 19, and driven by the variable hydraulic motor 15, the endless chain 25 is rotated on both sides. It is designed to circulate between sprockets 23 and 24. This endless chain 25
A pin 26 erected on one link constituting the carriage 13 is connected to the lower surface of the carriage 13 so that it can rotate freely and move relatively freely in the transport direction of the conveyor 1. 13 is adapted to reciprocate across the conveyor 1 at right angles. In addition, limit switches 29 and 30 are attached to fixtures 27 and 28 fixed to the side surfaces of the vertical frame 11 on both sides, and the carriage 13 reaches the turning point of its reciprocating stroke, as shown by chain lines in FIG. when the side surface is the stylus 29a,
The limit switches 29 and 30 are activated by contacting the limit switch 30a.

In addition, 31 is a variable hydraulic pump that supplies hydraulic oil to the variable hydraulic motor 15, 32 is an electromagnetic directional control valve interposed therebetween, and 33 is a stop control device with a built-in counter, which controls the limit switch 2.
9 and 30 are activated, a stop signal is issued from the stop control device 33 only until the pulses emitted from the pulse transmitter 7 reach an arbitrarily set constant value, and during that time the directional control valve 32 is closed to the hydraulic pressure. It operates in the direction of cutting off the supply, and returns to the direction of supplying hydraulic pressure to the variable hydraulic motor 15 at the same time as the stop signal disappears.

Next, the operation of this embodiment will be explained.

While supplying the steel plate a onto the conveyor 1 and conveying it from the right to the left in the figure at a constant speed, the variable hydraulic motor 1
5 is rotated at a constant speed to cause the spray gun 14 to reciprocate, the relative locus L of the spray gun 14 with respect to the steel plate a is determined by the transport speed of the steel plate a and the movement of the spray gun 14, as shown in FIG. An outgoing stroke L1 inclined at a constant angle determined by combining speeds, and a backward stroke L2 inclined at the same angle in the opposite direction;
A zigzag pattern consisting of a return stroke L3 in which a straight line with a length corresponding to the stop time T of the carriage 13 is inserted in the middle of an ellipse obtained by extending the semicircular path at the turning part of the endless chain 25 in the conveying direction of the conveyor 1. It takes shape. Then, the stop control device 3
When the stopping time T is determined by the adjustment in step 3, as shown in FIG. 7, the coating bands g are continuous and in contact with each other, and there are no uncoated areas or overcoated areas, and uniform coating can be achieved.

When the speed of the conveyor 1 increases due to an increase in the speed of the entire production line for steel plate a, if the movement speed of the spray gun 14 does not change, the forward stroke L1 and the backward stroke L2 of the trajectory L will change as described above. The inclination angle of the pulse transmitter 7 increases.
Since the transmission cycle of is shortened, even if the set value of the stop control device 33 is not changed, the time for transmitting the same number of pulses as the set value is shortened, the stop time T is shortened, and the turn-back process L3 is shortened. becomes shorter, the pitch of the outgoing stroke L1 hardly changes, and the pitch of the 8th
As shown in the figure, even if the paint is sprayed with the same spray width W as shown in FIG. 7, there will be no uncoating or overcoating, and the coating can be applied almost uniformly. If a satisfactory painted surface cannot be obtained with the above-mentioned automatic adjustment alone, the set value of the stop control device 33 can be adjusted. Conveying speed and spray gun 1
If the configuration is such that an appropriate stopping time is calculated from the movement speed in step 4 and the settings are automatically changed to correspond to this time, manual adjustment is not necessary.

Further, the pulse transmitter 7 may be omitted, and an analog timer may be used in the stop control device 33 to arbitrarily set the stop time. In this case as well, an arithmetic circuit may be incorporated to set the stop time. By automatically changing the time in almost inverse proportion to the conveyance speed of the conveyor 1, even if the conveyance speed of the conveyor 1 changes, the coating strips g can always be kept in contact with each other to ensure uniform coating. can be done.

The endless chain 25, which is the driving device for the spray gun 14, may be stopped by disconnecting the clutch.

In addition, the method and apparatus of the present invention can be used not only when changing the conveying speed of the object to be coated, but also by changing the movement speed of the spray gun for the purpose of adjusting the thickness of the coating film. It can also be effectively applied when the locus of movement relative to the object to be coated changes.

As clarified by the above explanation, the automatic painting method of the present invention reciprocates the spray gun in a direction substantially perpendicular to the direction of conveyance of the object to be coated, with respect to the object being conveyed in one direction. In an automatic painting method in which paint is injected while the paint is being sprayed, the gist is to stop the spray gun at the halfway point of the reciprocating stroke for an arbitrary period of time, and the spray gun's reciprocating speed is When the trajectory of the spray gun relative to the object to be coated changes due to a change in Therefore, it is possible to perform uniform coating with the same spray width. The apparatus of the present invention also includes a conveyance device that conveys the object to be coated in one direction at an arbitrary speed, a drive device that reciprocates the spray gun in a direction substantially perpendicular to the direction of conveyance of the object, and a drive device that causes the spray gun to reciprocate. a detection device that detects when the turning point of the exercise stroke has been reached;
The present invention is characterized in that it comprises a stop device that stops the drive device for an arbitrary period of time in response to a detection signal from the detection device, and this configuration provides the effect that the method of the present invention described above can be carried out effectively.

[Brief explanation of the drawing]

Figures 1 and 2 show an example of a conventional automatic painting device, Figure 1 is a plan view, Figure 2 is a sectional view taken along the line A-A in Figure 1, and Figures 3 and 4 are an embodiment of the present invention apparatus. FIG. 3 is a plan view, FIG. 4 is a sectional view taken along the line B-B in FIG. FIG. 3 is a plan view of the relative movement trajectory of the spray gun in the method and apparatus of the present invention. a: Steel plate (workpiece), 1: Conveyor, 7: Pulse transmitter, 14: Spray gun, 15: Variable hydraulic motor, 25: Endless chain, 29, 30: Limit switch, 32: Directional switching valve, 33: Stop Control device.

Claims (1)

[Scope of Claims] 1. An automatic coating method in which a spray gun is reciprocated in a direction substantially perpendicular to the conveyance direction of the object to be coated while spraying paint onto the object to be coated, which is being conveyed in one direction. An automatic painting method characterized by stopping a spray gun for an arbitrary period of time at a turning point in a reciprocating stroke. 2. The automatic coating method according to claim 1, wherein the stop time of the spray gun is automatically changed in substantially inverse proportion to the conveyance speed of the object to be coated. 3. A conveying device that conveys the object to be coated in one direction at an arbitrary speed, a drive device that reciprocates the spray gun in a direction substantially perpendicular to the direction of conveyance of the object, and a drive device that moves the spray gun back and forth in a direction substantially perpendicular to the direction of conveyance of the object to be coated. An automatic painting device comprising: a detection device that detects when the paint has been reached; and a stop device that stops the drive device for an arbitrary period of time based on a detection signal from the detection device. 4. The automatic coating apparatus according to claim 3, wherein the stop device is configured to automatically change the stop time of the drive device in substantially inverse proportion to the conveyance speed of the object to be coated.