LIGHTING DEVICE FOR A SPRAY GUN AND SPRAY GUN WITH SUCH A LIGHTING DEVICE

Description

[0001] The invention relates generally to the technical field of spray coating of objects or items.

[0002] According to one aspect of the invention, this relates in particular to a spray gun for the preferably manual spray coating of objects with powdered coating material. However, the invention is not limited to this, but can also be used for spray guns for the automatic spray coating of objects, in particular for spray coating objects with liquid coating material.

[0003] In particular, the invention relates to a powder spray gun, wherein the spray gun has a handle part and a gun barrel connected to the handle part.

[0004] Spray guns of this type are at least known in principle from the prior art. For example, publication EP 0 383 030 A1 relates to a spray gun for spray coating objects with coating powder. The spray gun known from this prior art has a handle and a barrel connected to the handle.

[0005] When spray coating objects, it is important to achieve the most homogeneous and uniform coating possible. This goal is often only achievable with considerable effort, especially for complex objects that have undercuts, openings, or irregular surfaces.

[0006] In manual coating processes, especially with objects being coated, the experience and skill of the operator using the spray gun are crucial for achieving the best possible coating result. The operator's experience is based primarily on knowing how to guide the manual spray gun relative to the object being coated to maintain a consistent distance between the spray gun's nozzle and the surface of the object.

[0007] There is a fundamental need to simplify the spray coating process for the operator of a spray gun so that even inexperienced operators can achieve the best possible coating result.

[0008] This is especially true for applications where the spray gun has to be operated under unfavorable lighting conditions. The problem here is that the work area (i.e., the surface of the object to be coated) is not optimally illuminated, making it extremely difficult for the spray gun operator to assess the quality and homogeneity of the sprayed coating material immediately during application. If quality defects are discovered during subsequent inspection under better lighting conditions, a complete recoating is necessary to achieve the required homogeneity.

[0009] If, on the other hand, the quality of the coating with coating material could be assessed by the spray gun operator under favorable lighting conditions during the application of the coating material, this would lead to significant time and cost savings and contribute to environmental protection due to the reduced use of often environmentally harmful coating materials.

[0010] Document US 10,539,318 B2 relates to a powder spray gun with a lighting device connected to the gun barrel at an upstream end of the powder spray gun.

[0011] Publication CN 201878412 U relates to a spray gun for wet paint with a lighting device arranged in the area of ​​the spray nozzle.

[0012] Another spray gun is known from the publication CN 202113973 U.

[0013] Finally, document US 2016 / 0167070 A1 concerns a water spray gun with a lighting device integrated into the spray channel.

[0014] The invention aims to solve the problem of creating a lighting device that can be added to a spray gun as needed, in particular to retrofit commercially available spray guns with a corresponding lighting device. This lighting device should, on the other hand, not impair the ease of use of the spray gun.

[0015] This problem is solved by the subject matter of independent claim 1.

[0016] Accordingly, the invention relates in particular to a powder spray gun, wherein the spray gun has a handle and a barrel connected to the handle. According to the invention, it is particularly provided that the spray gun further comprises a lighting device for continuously or as needed illuminating and / or exposing at least one area of ​​an object to be coated with the spray gun. The lighting device is detachably and replaceably connected to the spray gun.

[0017] In the solution according to the invention, the lighting device comprises an annular light source carrier with at least one light source, in particular in the form of an LED. The light source carrier extends around a downstream region of the pistol barrel, on which it is radially supported.

[0018] The solution according to the invention has several advantages. In particular, the lighting device is suitable for retrofitting a conventional spray gun. The ring-shaped light source carrier provides a ring light that allows for optimal illumination of at least one area of ​​the object to be coated. Because the light source carrier extends around a downstream area of ​​the gun barrel, on which it is radially supported, no structural modifications to the spray gun are necessary to equip it with the lighting device.

[0019] According to the invention, the barrel of the spray gun further comprises a pistol grip, at the downstream end of which a nozzle is arranged, through which the coating material (coating powder) is atomized during the spraying process. The nozzle is preferably interchangeably connected to the pistol grip by means of a coupling nut, which is at least partially sleeve-shaped.

[0020] Furthermore, it is provided that the area on which the ring-shaped light source carrier is supported is a section of the retaining nut, and in particular a sleeve-shaped section of the retaining nut. Of course, other embodiments are also possible.

[0021] In order to ensure optimal alignment of the light source carrier relative to the pistol barrel, the pistol barrel and in particular the retaining nut can have at least one indexing means, which in particular interacts in a form-fitting manner with preferably at least one counter-indexing means of the light source carrier designed complementary to the indexing means, such that in particular a rotational alignment of the light source carrier with respect to the pistol barrel is effected.

[0022] Alternatively or additionally, it may be provided that the ring-shaped light carrier is movable relative to the pistol barrel in an axial and / or radial direction and can be locked in the selected position by suitable positioning means.

[0023] In preferred embodiments of the solution according to the invention, at least one connecting web is provided, preferably extending in the longitudinal direction of the pistol barrel in a region, which is connected on the one hand to the light source carrier and on the other hand is preferably detachably connected or connectable to an upstream region of the pistol barrel, wherein the at least one connecting web extends outside the pistol barrel and at least partially supports the light source carrier.

[0024] In these embodiments of the spray gun according to the invention, it can be provided that an electrical connection is formed by the at least one connecting bridge between an electrical connection, particularly in the upstream region of the gun barrel, and the at least one light source of the light source holder. The electrical connection can, for example, be an electrical conductor extending at least partially through the at least one connecting bridge.

[0025] In particular, the connecting bridge can therefore be tubular, at least in some sections. Alternatively or additionally, the connecting bridge can also consist of an electrically conductive material that forms the electrical connection.

[0026] The electrical connection, particularly on the upstream side of the pistol barrel, is galvanically connected, in particular via an electrical conductor running at least partially through the grip part, to an adapter preferably provided on the lower part of the grip part.

[0027] According to the invention, a plurality of light sources, in particular each in the form of an LED, are provided, wherein the light sources are arranged in an equidistant manner around the ring-shaped light source carrier and are oriented towards the downstream end region of the pistol stock.

[0028] In addition, it may be possible to direct and / or focus the illumination provided by the light sources or the at least one light source onto different areas of the object to be coated. The focus of the illumination can also preferably be adjustable (for example, analogous to the focusing of a flashlight) in order to optimally illuminate areas of the object to be coated at different distances.

[0029] However, the lighting can also be fixed in focus or focusable in increments to indicate to the operator of the spray gun - especially during vocational training - the optimal distance of the spray gun to the object to be coated.

[0030] According to further developments of the spray gun according to the invention, a purge air device is provided for selectively or as needed flowing compressed air around the lamp holder, in order to keep the at least one lamp of the lamp holder free of coating material. Since compressed air is already required for the operation of the spray gun, and this is usually already supplied to the spray gun, the implementation of such a purge air device is possible without significant effort.

[0031] According to embodiments of the spray gun according to the invention, it is designed for the electrostatic spray coating of objects and has at least one charging electrode for this purpose, in order to transfer electrostatic charge to the coating material sprayed or to be sprayed with the spray gun. The charging electrode has an electrical potential that differs from the electrical potential of the object to be coated in such a way that the charged coating material is electrostatically attracted to the object to be coated.

[0032] In this electrostatic spray coating process, the coating material can be positively or negatively electrostatically charged either immediately before or after the outlet opening, particularly the nozzle opening, of the spray gun. The at least one charging electrode used for this purpose is connected to a high electrical voltage in the range of 40 kV to 140 kV. The object to be coated has a different electrical potential, preferably ground potential. The atomized coating material moves along electric field lines generated by the high voltage between the charging electrode and the object to be coated. Once a thin layer of coating material has formed on the object, this layer repels subsequent coating material particles due to its electrical charge, as these particles are similarly electrostatically charged.This means that only a limited layer thickness can be applied to the object being coated in a single step. Furthermore, the mutual repulsion of the coating material particles on the surface of the object creates an unstable force balance. This unstable force balance can result in an uneven coating surface rather than a smooth, flat one, forming a kind of "hilly landscape" which, during the subsequent curing process, creates a so-called "orange peel" effect and should therefore be avoided if possible.

[0033] The electrostatic attraction of the object to be coated differs, particularly at corners, edges, and openings, compared to larger, flat surfaces. Corners and edges are typically coated less effectively or with a thinner layer than adjacent larger areas. Under the influence of the electrostatic field, the coating material particles are drawn around the outer edges and openings of the object. Due to the object's electrostatic attraction, they are then drawn to its reverse side, thus coating that side as well. This can be described as "electrical perimeter coating."

[0034] By using a counter electrode that extracts free ions from the sprayed coating material stream, the surface finish and the penetration of the coating material into recesses of the object being coated can be improved. Furthermore, a thicker layer of coating material can be applied to the object in a single spraying process without excessive coating material particles bouncing off or being electrostatically repelled. In particular, an "orange peel"-like surface texture can be avoided.

[0035] For this reason, further developments of the spray gun according to the invention provide that the spray gun has at least one counter electrode arranged near the charging electrode, which is connected to a different electrostatic potential than the charging electrode, so that it absorbs at least a portion of the free ions generated during the electrostatic charging of the coating material. In particular, it is provided in this context that the ring-shaped lamp carrier carries the at least one counter electrode.

[0036] This implementation of the invention has the advantage that the light source carrier thus has a dual function: firstly, the light source carrier serves to hold at least one light source in order to continuously or as needed illuminate at least one area of ​​the object to be illuminated. Secondly, the light source carrier serves to hold at least one counter electrode in order to absorb at least some of the free ions generated during the electrostatic charging of the coating material and thus improve the coating result.

[0037] According to further developments of the last-mentioned embodiment, in which the ring-shaped light source carrier carries the at least one counter electrode, it is provided that the at least one connecting bridge extending in the longitudinal direction of the pistol barrel also serves to form an electrical connection between a potential connection and the at least one counter electrode.

[0038] As with regard to the light sources which are received by the ring-shaped light source carrier, it is preferred that several counter electrodes, preferably in the form of needle electrodes, protrude from the ring-shaped light source carrier.

[0039] To capture the free ions generated during the electrostatic charging of the coating material as efficiently as possible using at least one counter electrode, the distance between the charging electrode and the counter electrode should be smaller than the distance between the charging electrode and the object to be coated. Specifically, the distance between the charging electrode and the counter electrode should be one-third to one-half of the distance between the charging electrode and the object to be coated.

[0040] The counter electrode is preferably arranged at a distance from a coating material cloud atomized by the spray gun, wherein the distance between the counter electrode and the coating material cloud is smaller than the distance between the charging electrode and the object to be coated.

[0041] The present disclosure relates not only to a spray gun with a corresponding lighting device that can be interchangeably connected to the spray gun, but also to a lighting device as such for a spray gun, in particular a spray gun of the aforementioned type. The lighting device thus serves for the continuous or on-demand illumination of at least one area of ​​an object to be coated with the spray gun. The lighting device can be detachably and, in particular, interchangeably connected to the spray gun and has an annular light source carrier with at least one light source, in particular in the form of an LED, wherein the light source carrier is designed such that it can extend around a downstream area of ​​the spray gun barrel and can be radially supported on it.

[0042] Preferably, the lighting device has at least one connecting bridge which serves to support the ring-shaped light source carrier in the assembled state of the lighting device, wherein the at least one connecting bridge also serves in particular to supply the at least one light source of the light source carrier with electrical energy.

[0043] An exemplary embodiment of the spray gun according to the invention is described below with reference to the drawings.

[0044] They show: FIG. 1 shows a schematic and side view of an exemplary embodiment of the spray gun according to the invention; and FIG. 2 shows a schematic and downstream view of the exemplary embodiment of the spray gun according to the invention. FIG. 1 .

[0045] The spray gun 1 according to the invention, as shown schematically in the drawings with reference to an exemplary embodiment, serves in particular to apply coating material 21 to a surface FIG. 1 to apply the schematically depicted object 20.

[0046] In the illustrated embodiment of the spray gun 1 according to the invention, the coating material 21 to be applied to the object 20 is in particular an electrostatically charged or chargeable coating powder.

[0047] However, it is intended that a spray gun 1 constructed according to the invention can also be used to apply other coating materials 21 instead of electrostatically charged coating powder to an object 20. For example, the spray gun 1 can be used to apply liquid coating materials 21 to an object 20.

[0048] The spray gun 1, as shown schematically in the drawings, essentially has a handle part 2 and a gun barrel 3 connected to the handle part 2.

[0049] The manually gripping handle 2 has a base body which is connected to a base body of the pistol barrel 3. Preferably, the base body of the handle is formed integrally with the base body of the pistol barrel 3, for example as a monolithic injection-molded plastic part. In this way, a base body of the spray gun 1, in particular a single piece, is created.

[0050] The barrel 3 of the spray gun 1 has a first (front or downstream) section extending to a nozzle assembly 8 and a second (rear or upstream) section at the rear. The handle 2 is positioned between the front and rear sections, preferably in a position where it is located above the center of gravity of the entire barrel 3. This improves the comfort of the operator of the spray gun 1, particularly during extended use.

[0051] The basic body of the spray gun 1 is formed in one piece from an electrically insulating (polymeric) material.

[0052] The coating material 21 to be sprayed, in particular coating powder carried in an airflow, is supplied to the spray gun 1 from a powder source not shown in the drawings. The stream of coating powder carried in the air is fed from a coating material supply line through an adapter 14 provided at the lower part of the handle 2 into a coating material line running through the handle 2.

[0053] Furthermore, connections 15 for compressed air and connections 16 for electrical energy are provided at the lower end of the handle part 2.

[0054] The exemplary embodiment of the spray gun 1 according to the invention is characterized in particular by the fact that it has a lighting device 4 in order to continuously or as required illuminate at least an area of ​​an object 20 to be coated with the spray gun 1.

[0055] The lighting device 4 is detachably and in particular interchangeably connected to the spray gun 1 and has a ring-shaped light carrier 5 with at least one light source 6, in particular in the form of an LED, and preferably with a plurality of light sources 6, in particular each in the form of an LED.

[0056] As can be seen from the front viewpoint FIG. 2 The light sources 6 are arranged in an equidistant manner around the ring-shaped light source carrier 5 and are oriented towards the downstream end area of ​​the pistol stock 7.

[0057] The ring-shaped light carrier 5 extends around a downstream area of ​​the pistol barrel 3, on which it is radially supported.

[0058] In the exemplary embodiment of the spray gun 1 according to the invention shown in the drawings, it is particularly provided that the gun barrel 3 has a gun shaft 7, at the downstream end of which a nozzle 8 is arranged, which is preferably interchangeably connected to the gun shaft 7 by means of a coupling nut 9, which is preferably at least partially sleeve-shaped. It is particularly provided that the area on which the annular light source carrier 5 is supported is an area of ​​the coupling nut 9, and in particular a sleeve-shaped area of ​​the coupling nut 9.

[0059] According to the side view FIG. 1It can be seen that the lighting device 4 further comprises a connecting web 10 extending at least partially in the longitudinal direction of the pistol barrel 3, which is connected on the one hand to the light source carrier 5 and on the other hand is preferably detachably connected or connectable to an upstream area of ​​the pistol barrel 3. The connecting web 10 extends outside the pistol barrel 3 and supports at least part of the light source carrier 5.

[0060] Preferably, the connecting web 10 forms an electrical connection between an electrical connection 17 and the light sources 6 of the light source carrier 5. For this purpose, the upstream end region of the connecting web 10 can be connected to the electrical connection 17, which is provided, for example, in the rear shell of the spray gun 1.

[0061] The electrical connection 17 is galvanically connected, in particular via an electrical line running at least partially through the handle part 2, to an adapter 14 preferably provided on the lower part of the handle part 2 or to a connection provided on the lower part of the handle part 2.

[0062] The object 20 to be coated is usually carried by a transport device and transported through a spray coating booth. The transport device is generally grounded, so that the object 20 it carries is also grounded by the transport device.

[0063] Preferably, the exemplary embodiment of the spray gun 1 according to the invention shown in the drawings is used for electrostatic spray coating and has at least one charging electrode 11 located axially in the powder flow. The charging electrode 11 is located in the outlet region of the nozzle 8 or in the immediate vicinity upstream or downstream of the outlet region and is connected to a high-voltage generator which generates an electrical output voltage in the range between 40 kV and 140 kV. The high-voltage generator can be arranged inside the gun barrel 3 of the spray gun 1 or externally thereto.

[0064] In the spray gun 1 according to the invention, as shown schematically in the drawings, a needle-shaped charging electrode 11 arranged axially in the powder stream is used in the outlet region of the nozzle 8. Instead of one axial needle-shaped charging electrode 11 in the outlet region, several charging electrodes can also be arranged in the core of the coating material 21 stream or around it.

[0065] The high-voltage electric field generates electric field lines that extend from the tip of the charging electrode 11 to the object 20 to be coated. The powder particles sprayed at the nozzle outlet move along these field lines onto the object 20. In doing so, they also penetrate into recesses and through openings in the object 20. As a result of the "electrical spillover effect," the particles also reach the back of the object 20, particularly at its edges. Electrostatic interactions result in a greater coating thickness at protruding edges or corners of the object 20 than on raised surfaces or larger flat areas.

[0066] To optimize the coating result, the spray gun 1, shown schematically in the drawings, has an annular counter electrode 12, which is arranged on or integrated into the annular light source carrier 5 together with the light sources 6. The annular counter electrode 12 has a different electrical potential than the charging electrode 11 and serves to absorb free ions that are generated during the electrostatic charging of the coating material powder.

[0067] The side view in FIG. 1 It can be seen that at least one galvanically conductive grounding element 17 is integrated into the rear housing of the spray gun 1. This at least one grounding element 17 serves to ground the counter electrode 12 of the spray gun 1 or to bring it to a grounding potential.

[0068] For this purpose, in the assembled state of the spray gun 1, the grounding element 17 integrated in the rear housing can be connected via a grounding conductor, such as a galvanically conductive connecting bridge 10, to the counter electrode 12 located near the charging electrode 11 of the spray gun 1, in order to connect the counter electrode 12 to an electrical potential that is different from the electrical potential to which the charging electrode 11 is connected. In this way, at least a portion of the free ions generated during the electrical charging of the coating powder can be absorbed via the counter electrode 12 and the grounding element 17 integrated in the rear housing.

[0069] Preferably, the grounding element 17 integrated in the rear shell is electrically connected to the grounding or a potential connection via an electrical conductor, which runs particularly inside the handle of the spray gun 1. Reference symbol list

[0070] 1 Spray gun 2 Grip 3 Gun barrel 4 Lighting device 5 Bulb holder 6 Bulb 7 Gun stock 8 Nozzle 9 Union nut 10 Connecting bridge 11 Charging electrode 12 Counter electrode 13 Grounding element 14 Adapter 15 Compressed air connection 16 Electrical connection 17 Electrical / grounding connection 20 Object 21 Coating material

Claims

1. A spray gun (1) in form of a powder spray gun, wherein the spray gun (1) comprises a handle member (2) and a gun barrel (3) connected to the handle member (2), wherein the spray gun (1) further comprises a lighting device (4) for the continuous or as required illuminating and / or lighting of at least one area of an object (20) to be coated with the spray gun (1), wherein the lighting device (4) is detachably and replaceably connected to the spray gun (1), and wherein the lighting device (4) comprises an annular illuminant carrier (5) having at least one illuminant (6), particularly in the form of an LED, wherein the illuminant carrier (5) extends around a downstream region of the gun barrel (3) on which it is radially supported, wherein the gun barrel (3) comprises a gun shaft (7) with a nozzle (8) arranged at its downstream end region which is replaceably connected to the gun shaft (7) by means of a sleeve-shaped union nut (9), wherein the area on which the annular illuminant carrier (5) is supported is a sleeve-shaped area of the union nut (9), wherein a plurality of illuminants (6), each particularly in the form of an LED, is provided, wherein the illuminants (6) are in particular arranged in equidistant distribution around the annular illuminant carrier (5) and oriented toward the downstream end region of the gun shaft (7).

2. The spray gun (1) according to claim 1, wherein the gun barrel (3) and in particular the union nut (9) comprises at least one indexing means which in particular interacts in a form-fitting manner with preferably at least one counter-indexing means of the illuminant carrier (5) of complementary design to the indexing means so as to effect particularly a rotational alignment of the illuminant carrier (5) with respect to the gun barrel (3).

3. The spray gun (1) according to claim 1 or 2, wherein at least one connecting bar (10) preferably extending longitudinally in certain areas of the gun barrel (3) is provided which is connected on one side to the illuminant carrier (5) and is preferably detachably connected or connectable on the other side particularly to an upstream region of the gun barrel (3), wherein the at least one connecting bar (10) extends beyond the gun barrel (3) and at least partially supports the illuminant carrier (5).

4. The spray gun (1) according to claim 3, wherein an electrical connection is formed between an electrical connector (17) and the at least one illuminant (6) of the illuminant carrier (5) by the at least one connecting bar (10), wherein the electrical connection is preferably an electrical line extending at least through sections of the at least one connecting bar (10).

5. The spray gun (1) according to claim 4, wherein the electrical connector (17) is galvanically connected to an adapter (14) preferably provided in the lower region of the handle member (2) by means of an electrical line running at least through sections of the handle member (2).

6. The spray gun (1) according to one of claims 1 to 5, wherein a purge air device is provided for flowing compressed air around the illuminant carrier (5), in particular selectively or as required, particularly so as to keep the at least one illuminant (6) of the illuminant carrier (5) free of coating material.

7. The spray gun (1) according to one of claims 1 to 6, wherein the spray gun (1) has at least one charging electrode (11) for transferring electrostatic charge to the coating material (21) being or to be sprayed with the spray gun (1), wherein the charging electrode (11) has an electric potential which differs from the electric potential of the object (20) to be coated such that the charged coating material (21) is electrostatically attracted to the object (20) to be coated.

8. The spray gun (1) according to claim 7, wherein the spray gun (1) has at least one counter electrode (12) arranged in the proximity of the charging electrode (11) which is connected to a different electrostatic potential than the charging electrode (11) so that it absorbs at least some of the free ions generated when the coating material (21) is electrostatically charged, wherein the at least one counter electrode (12) is accommodated by the annular illuminant carrier (5).

9. The spray gun (1) according to claim 8, wherein at least one connecting bar (10) preferably extending longitudinally in certain areas of the gun barrel (3) is provided which is connected on one side to the illuminant carrier (5) and is detachably connected or connectable on the other side to an upstream region of the gun barrel (3), wherein an electrical connection is formed between a potential terminal (17) and the at least one counter electrode (12) by the at least one connecting bar (10); and / or wherein multiple counter electrodes (12) in the form of needle electrodes protrude from the annular illuminant carrier (5).

10. The spray gun (1) according to claim 8 or 9, wherein the distance between the charging electrode (11) and the counter electrode (12) is smaller than the distance between the charging electrode (11) and the object (20) to be coated.

11. The spray gun (1) according to claim 10, wherein the distance between the charging electrode (11) and the counter electrode (12) is one-third to half of the distance between the charging electrode (11) and the object (20) to be coated.

12. The spray gun (1) according to one of claims 8 to 11, wherein the counter electrode (12) is arranged at a distance from a cloud of coating material atomized by the spray gun (1), and wherein the distance between the counter electrode (12) and the coating material cloud is smaller than the distance between the charging electrode (11) and the object (20) to be coated.

13. The spray gun (1) according to one of claims 8 to 12, wherein the counter electrode (12) is connected to ground potential.

14. The spray gun (1) according to one of claims 1 to 13, wherein the annular illuminant carrier (5) is axially and / or radially displaceable relative to the gun barrel (3) and able to be locked in the selected position by suitable positioning means.