JPS61125461A - Device for controlling discharge of painting spray gun fixed to variable stroke elevator - Google Patents

Abstract

PURPOSE:To paint in fixed film thickness a material to be painted having different vertical width by fixing a spray gun to a variable stroke elevator, and changing the discharge of paint in proportion to the stroke of the spray gun. CONSTITUTION:An elevator 3 whose lifting stroke is variable is provided in the vicinity of a painting line, and a spray gun 23 is fixed to the elevator. The height between the upper and the lower edge of a material (a) to be painted is detected by a detector such as a photocell 27 on this side of a painting position, and a signal for regulating the upper and the lower limit of the lifting stroke of the elevator 3 is outputted on the basis of the signal from the detector 27. Consequently, the discharge of paint from the spray gun 23 is regulated almost in proportion to the lifting stroke of the elevator 3. The discharge from the spray gun is thus controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a spray gun for painting, which is attached to an elevating body of an elevating device with a variable elevating stroke, which is provided near a conveyor line that conveys objects to be coated in a horizontal direction. The present invention relates to a device that automatically changes the discharge amount in proportion to the stroke length of an elevating body.

The key point to be solved by the prior art and the invention is that each spray gun that is conveyed in front of it from a spray gun that reciprocates at a constant speed up and down on the side of a conveyance line that conveys objects to be coated at a constant speed in the horizontal direction. In an automatic painting line that continuously coats objects with a large vertical width by spraying paint toward the object, the stroke length of the spray gun is adjusted to match the object being flowed down the conveyor line. By matching the vertical width of the object to be coated, it is possible to eliminate unnecessary movement of the spray gun and avoid unnecessary spraying of paint, making painting work more economical and efficient. If you change it to match the width, the number of strokes per unit time of the spray gun will change. For example, if you halve the stroke length of the spray gun to match the vertical width of the object to be painted, the number of strokes per unit time will double. If you paint without changing the amount of paint discharged from the spray gun or gun, the amount of paint sprayed per unit area of the object will double, making the coating thicker than necessary. It is necessary to increase or decrease the amount of paint discharged by the spray gun in proportion to the stroke length of the spray gun, that is, the vertical width of the object to be painted. It was done manually. However, when objects with different shapes are randomly flowed down the conveyor line, the vertical width of the objects conveyed in front of the spray gun frequently changes, so the stroke length of the spray gun must be adjusted accordingly. must be changed frequently,
As a means of changing it, it is possible to automatically change it by detecting the vertical width of each object to be coated beforehand on the conveyance line before the coating position and controlling the reciprocating drive device of the spray gun using the detection signal. As the stroke length of the spray gun changes, it is impossible to manually change the amount of paint discharged from the spray gun each time in proportion to the stroke length of the spray gun.

The present invention was completed in view of these points, and
The amount of paint discharged from the spray gun can be automatically changed in proportion to the stroke length of the spray gun. It is an object of the present invention to provide a discharge amount control device for a spray gun attached to a variable stroke lifting device.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a chain conveyor that suspends and conveys a workpiece a to be coated at a constant speed in the horizontal direction. A base 2 is installed on the floor on the side of this chain conveyor 1. An elevating device 3 is placed on the upper surface so as to be movable back and forth by means of an axle at its lower end, and is positioned forward and backward by rotation of a screw 4 of the base 2 screwed to the lower end of the elevating device 3. Inside the lifting device 3, two vertically long guide rails 5.5 are erected parallel to each other with an interval left and right. An endless chain 12 is connected to an output shaft 8 of a hydraulic motor 7 fixed to the lower part of the lifting device 3, and is connected to a sprocket 10 supported at the lower part between both guide rails 5, S. , this endless chain 12 is connected to a bracket 13 of an elevating body 14 that is supported vertically and freely between both guide rails 5.5, and the hydraulic motor 7 is driven by one hydraulic fluid as shown in FIG. Entrance/exit 1
5.16 is connected to a hydraulic drive source in the hydraulic unit 20 via a directional switching valve, and rotates in alternate directions by switching the directional switching valve, thereby causing the hydraulic motor 7 to rotate in alternate directions. The rotation causes the endless chain 12 to move up and down between the sprockets 6.10, causing the elevating body 14 to reciprocate along the guide rail 5.5. , an elongated support 21 with both ends protruding from both left and right sides of the lifting bag [3] is fixed horizontally, and a support rod 22 fixed to one end of the support 21 and protruding forward is attached to the tip of the support rod 22 to be coated. Thing a
A spray gun 23 is horizontally supported by a mounting rod.

This spray gun 23 is of an air atomization type in which paint ejected from a nozzle is atomized by an air flow ejected from around the nozzle, and as shown in FIG. Paint hose 2 to gear pump 25
5 elevators connected through 6! ! ! 3, the chain conveyor 1 at the front position in the conveyance direction of the object a to be coated
on both sides.

Photocell 27 that detects the heights of the upper and lower edges of the object a suspended on the chain conveyor 1 and sends out a detection signal.
is arranged, and the detection signal of the phototube 27 is the control table! 28
Further, an encoder in the lifting device 3 that detects the height of the spray gun 23 and sends out a detection signal is connected to the input portion of the control device 28 .

The output section of the control device 28 is connected to the directional control valve of the hydraulic unit 20 and the variable motor 24 of the gear pump 25, respectively. This control device 28 detects the detection signal values of the heights of the upper and lower edges of the object a sent from the phototube 27, and encodes the detected signal values when the object a approaches the front of the spray gun 23. When the detection signal value of the height of the spray gun 23 sent from the respective hydraulic units 2
A switching signal is sent to the direction switching valve 0, and the vertical width of the object a is calculated based on the detection signal of the height of the upper and lower edges of the object a sent from the phototube 27. control voltage proportional to the calculated value obtained by multiplying the value obtained by dividing the value by the vertical width of the reference object to be painted by the reference paint discharge amount of the spray gun 23 set for the reference object to be painted. is sent to the variable motor 24 of the gear pump 25.

Next, the operation of this embodiment will be explained.

The heights of the upper and lower edges of each object to be coated a conveyed to the front of the spray gun 27 by the chain conveyor l are detected by the phototube 27 before reaching the front of the spray gun 23, respectively, as shown in FIG. Like, spray gun 2
3, the hydraulic motor 7 rotates in alternating directions at a predetermined period according to a switching signal sent from the control device 28 to the directional switching valve of the hydraulic unit 20, and the spray gun 23 moves toward the upper edge of the object to be coated. and change direction at the lower edge.

While reciprocating in a zigzag path shown by the two-dot chain line C with respect to the object to be coated a, a suitable amount is supplied to the spray gun 23 from a gear pump 25 driven by a variable motor 24 which is rotated by a control voltage sent out from a control bag [28]. is supplied and sprayed onto the object a, and when the object a passes in front of the spray gun 23, the spray gun 23
The vertical movement of and the spraying of paint are stopped, as shown in Figure 3.

Subsequently, when the object to be painted, which has a vertical width half that of the previous object a, comes in front of the spray gun 23, a switching signal sent from the control device 28 to the directional control valve causes the hydraulic motor 7 to By rotating alternately at half cycles, the spray gun 23 changes direction at the upper and lower edges of the object to be coated, and moves back and forth in a zigzag path shown by the two-dot chain line d with respect to the object to be coated. At the same time, gear pump 2
By sending half the control voltage from the control device 28 to the variable motor 24 of No. 5 as in the case of the object to be painted,
The rotational speed of the gear pump 25 is reduced to one-half, and the paint is injected from the spray gun 23 at half the amount as described above. Although the number of times is doubled, the amount of paint discharged from the spray gun 23 is halved, so the amount of paint sprayed per unit area is equal to that of the object to be painted.
The thickness of the coating film is the same as in the case of .

In this way, even if objects to be coated with different vertical widths are conveyed randomly by the chain conveyor 1.

A coating with a constant thickness is applied to each of the objects a and b.

In addition to the air atomization type spray gun shown in the above embodiment, the present invention can be applied to a spray gun in which the amount of paint discharged can be adjusted, such as an electrostatic spray gun having a rotating cup type atomization head.

Structure and Effects of the Invention As specifically explained in the above embodiments, the discharge amount control device of the painting spray gun attached to the variable stroke lifting device of the present invention is effective for controlling the discharge amount of the painting spray gun that is attached to the variable stroke lifting device of the present invention. A lifting device that can change the lifting stroke is installed nearby, and a spray gun for painting is attached to the lifting device.
A detection device for detecting the height of the upper and lower edges of the object to be coated is installed before the coating position on the conveyance line, and the detection signal from the detection device is used to tell the lifting device the upper and lower limit positions of the lifting stroke. Outputs the specified stroke signal,
The present invention further comprises a control device that outputs a discharge amount signal that defines the paint discharge amount of the spray gun to be substantially proportional to the vertical stroke length of the lifting device to a paint discharge amount control device. By aligning the upper and lower limit positions of the lifting stroke of the lifting device with the upper and lower edges of each workpiece conveyed to the front of the spray gun by the conveyance line, the length of the lift stroke of the spray gun is adjusted to the upper and lower ends of each workpiece. This is because the amount of paint discharged from the spray gun is controlled approximately in proportion to the stroke length of the spray gun when matching the width.

The amount of paint sprayed per unit area of the object to be painted is constant regardless of the stroke length of the spray gun, and it is possible to apply a coating with a constant thickness to each object having different vertical widths.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view and a block diagram of an embodiment of the present invention,
FIG. 2 is a partially cutaway side view thereof, and FIG. 3 is a perspective view illustrating the operation.

Claims (1)

[Claims] A lifting device that can change the lifting stroke is installed near the transport line that horizontally transports the objects to be coated, and a spray gun for painting is attached to the lifting body, and a spray gun for painting is attached to the lifting device, and a spray gun for painting is installed on the transport line in front of the painting position. A detection device for detecting the height of the edge and the lower edge is provided, and a stroke signal defining an upper limit position and a lower limit position of the lifting stroke is outputted to the lifting device based on the detection signal of the sensing device, and the spray gun a paint discharge amount control device for outputting a discharge amount signal to a paint discharge amount control device so that the paint discharge amount is approximately proportional to the lifting stroke length of the lifting device; spray gun discharge rate control device