The present invention relates to an improvement of electrostatic painting apparatus.
The electrostatic painting is a painting method which efficiently applies paint to a vehicle body with an electrostatic attractive force produced by setting the vehicle body at zero voltage and setting the paint at negative voltage. Also, it has been known to mount a painting gun on a robot (see, for example, FIGS. 1 and 2 of Japanese PCT-Based Patent Application Laid-Open Publication No. JP-A 2005-521544 (hereinafter referred to as “Patent Literature 1”).
After the paint is supplied to the painting gun 105, the robot 103 turns the arm 104 and ejects or sprays the paint onto the vehicle body 101 by means of the painting gun 105, as shown in
If painting of a multiplicity of different colors is to be performed by use of the single painting gun 105, so-called color change is executed. Cleaning liquid is supplied from the paint supply section 107 to the painting gun 105 to clean the painting gun 105. Next, paint of a desired new color is supplied from the paint supply section 107 to the painting gun 105. Because the paint supply section 107 and the painting gun 105 can be separated from each other, a cleaning range can be selectively limited to the painting gun 105, so that the cleaning liquid can be saved and the cleaning of the painting gun 105 can be done in a short time.
As paint is ejected or sprayed from the painting gun 105 in the illustrated example of
Further, it is necessary to make it difficult for the connection section 108 to be soiled or smeared with the uncoated paint. If the connection section 108 can be made difficult to be smeared, frequency of the cleaning operation can be lowered, and thus, decrease in the efficiency of the painting operation can be minimized.
In view of the foregoing prior art problems, it is an object of the present invention to provide an improved electrostatic painting apparatus which can reliably eliminate a possibility of the connection section being smeared with the uncoated paint.
In order to accomplish the above-mentioned object, the present invention provides an improved electrostatic painting apparatus, which comprises: a painting gun having at one end thereof a paint spray section for spraying paint onto an object of painting; a gun movement means for moving the painting gun; a paint storage section provided on the gun movement means; a connection section provided on the gun movement means and detachably connectable to an external paint supply section for receiving a supply of paint from the external paint supply section and supplying the received paint to the paint storage section, the paint storage section storing therein a predetermined amount of the paint supplied from the connection section and supplying the stored paint to the painting gun; and a peripheral wall surrounding the connection section.
So-called “uncoated paint”, which is a portion of the paint sprayed from the painting gun drifting around the painting gun without being appropriately painted onto an object of painting, such as a vehicle body, is blocked by the peripheral wall surrounding the connection section and thus does not reach the connection section (or is difficult to reach the connection section). As a result, according to the present invention, there can be provided an electrostatic painting apparatus where the connection section is difficult to be soiled or smeared with the uncoated paint. Because the connection section can be prevented from being easily smeared with the uncoated paint, the present invention can lower the frequency of the cleaning operation and thus minimize decrease in the efficiency of the painting operation.
Preferably, the connection section and the peripheral wall are provided at another end, remote from the one end, of the painting gun. Because the connection section is provided at the other end of the painting gun remote from the one end where the paint spray section is provided, the uncoated paint can be prevented from reaching the connection section with an increased reliability.
Preferably, the electrostatic painting apparatus of the present invention has a groove formed between the connection section and the peripheral wall. Thus, in case the paint leaks from between the connection section and the external paint supply section, the leaked paint is accumulated or retained in the groove. Thus, the present invention can eliminate a possibility of the leaked paint undesirably falling out onto the object of painting, such as a vehicle body.
Preferably, the external paint supply section has a fitting member provided thereon, and the connection section is connectable to the external paint supply section with the painting gun placed on the fitting member. Because the connection section can be connected to the external paint supply section with the painting gun placed on the fitting member, accurate positioning of the painting gun relative to the external paint supply section can be facilitated.
Preferably, the fitting member is a fork member of a generally U shape. In the case where the fitting member is constructed as such a fork member of a simple shape, it can be manufactured with ease at low cost.
Preferably, the fork member includes a bifurcated section formed in a generally semicircular arc shape, and the fork member is disposed in such a manner that the center of the semicircular arc of the fork member is aligned with the centerline of the external paint supply section. Further, the connection section is provided on the painting gun in such a manner that the center of the connection section can be aligned with the center of the generally semicircular arc of the bifurcated section of the fork member. Because the center of the generally semicircular arc is aligned with the centerline of the external paint supply section, a connector sleeve or mouthpiece of the external paint supply section can be positioned accurately relative to the connection section, and thus, the present invention can reliably prevent leakage of the paint from the connection section.
Preferably, the painting gun has a flange or a groove fittingly engageable with the fork member. By fittingly engaging the groove or flange of the painting gun with the fork member, the present invention can eliminate a need for enhancing accuracy of a stopped position of the gun movement means.
Certain preferred embodiments of the present invention will hereinafter be described in detail, by way of example only, with reference to the accompanying drawings, in which:
Reference is now made to
The paint spray section 12, which is also called “rotary atomizer head” or “bell cup”, atomizes paint by centrifugal force and sprays the atomized paint onto an object to he painted (object of painting). The painting gun 13 is in the form of a cylinder having the paint spray section 12 at its one end and having an ON/OFF valve 19 incorporated therein.
The gun movement section 14 is preferably in the form of a robot (21 in
The paint storage section 15 includes a first cylinder 23, a first piston 24 accommodated in the first cylinder 23, and a first actuator 25 for linearly moving the first piston 24 within the cylinder 23.
The external paint supply section 30 includes: a second cylinder 31 to which paint is supplied from a color change valve (CCV) section 42 via a paint path 41; a second piston 32 accommodated in the second cylinder 31; a second actuator 33 for linearly moving the second piston 32 within the cylinder 31; a hose 34 for directing paint pressed by the second piston 32 to the hose 32; a connector sleeve or mouthpiece 35 having the distal end of the hose 34 connected thereto; and a mouthpiece elevator section 37 for moving the mouthpiece 35 up and down along a vertical shaft 36.
The hose 34 may be a flexible hose, and the mouthpiece 35 is a block having a paint flow path therein.
The mouthpiece elevator section 37, which may be of any desired construction, is preferably a cylinder unit. In an alternatively the mouthpiece elevator section 37 may be in the form of a rack-and-pinion unit.
A fitting member 39 is disposed around a lower section of the vertical shaft 36. Although the fitting member 39 may be of any desired shape or form, it is preferably in the form of a fork member having a simple construction, and thus, the fitting member 39 will hereinafter be referred to as “fork member 39”.
The CCV section 42, painting gun 13, first actuator 25, second actuator 33 and mouthpiece elevator section 37 are controlled by a control section 43.
Preferably, as shown in
Next, a description will be given about general behavior of the electrostatic painting apparatus 10.
As shown in
Then, as shown in
Then, as shown in
Further, as shown in
Further, in the instant embodiment, the connection section 18 is surrounded by a peripheral wall 47. Because the connection section 18 is protected by the peripheral wall 47, the paint traveling as indicated by arrow (8) can pass by the other end 46 of the painting gun 13 without reaching the connection section 18. Consequently, the connection section 18 can be prevented from being undesirably coated or smeared with the paint 11. Even if a portion of the paint 11 adheres to the connection section 18, such a portion adhering to the connection section 18 is of a very small amount, and thus, the cleaning frequency of the connection section 18 can remain so low that it does not adversely influence the productivity of the painting operation.
In an alternative, the connection section 18 surrounded by the peripheral wall 47 may be provided on a side surface 48 of the painting gun 18, because the peripheral wall 47 functions as a guard for the connection section 18. Note, however, that the paint mist indicated by arrow (8) is smaller in amount than the paint mist indicated by arrow (7). Thus, in the case where the paint spray section 12 is provided at the one end of the painting gun 13, it is recommendable that the connection section 18 be disposed at the other end 46 remotest from the paint spray section 12.
The following describe in detail a more preferred embodiment of the connection section 18. According to the more preferred embodiment of the connection section 18, as shown in
If the paint 11 overflows from the peripheral wall 47, it might undesirably fall out onto the vehicle body. However, this preferred embodiment of the connection section 18 can avoid such an undesired possibility by virtue of the provision of the groove 49. Namely, in ease the paint mist adheres to and builds up or accumulates on the connection section 18, the preferred embodiment of the connection section 18 can prevent the accumulated paint from falling out onto the vehicle body by allowing the paint to fall into the moat-shaped groove 49. Note that, although the connection section 18 would change in posture depending on its usage, the paint (including the accumulated paint) can be prevented from readily jumping out of the groove 49 as long as it is accumulated in a bottom section of the groove 49, because the paint has a relatively high viscosity.
The following describe in detail the fork member 39. As shown in
Further, as shown in
Positioning the center 54 of the connection section 18 in alignment with the mouthpiece 35 (
Further, as shown in
Next, a description will be given about modifications of the present invention. As shown in
Further, as shown in
The above-described basic principles of the present invention are well suited for application to electrostatic painting apparatus in which a painting gun has a connection section and in which the connection section is connected to an external paint supply section to receive a supply of paint from the external paint supply section.
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Japanese Office Action and partial English translation dated May 13, 2014, 8 pages. |
Number | Date | Country | |
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20140103149 A1 | Apr 2014 | US |