Patent Grant
9433953
The invention relates to a reversible coating material nozzle for a spray gun for coating a workpiece with coating material.
When coating a workpiece with a coating material, such as paint, a spray gun if often used that sprays the pressurised coating material through a coating material nozzle. In particular if there are particles of dirt in the coating material, the coating material nozzle may become blocked. If the spray gun continues to be used, either no more coating material will be sprayed or only an insufficient quantity of coating material will still be sprayed. The coating material nozzle then has to be cleaned. To this end, the trigger of the spray gun is locked, for example using a trigger lock, such that no more coating material can exit from the spray gun. With an electrostatic spray gun, the locking of the trigger additionally ensures that a high voltage is no longer applied across the high-voltage electrode. The coating material nozzle can then be dismantled. The blocked coating material nozzle then has to be cleaned manually, for example with solvent and a fine cleaning needle. The coating material nozzle then has to be reinstalled in the spray gun. Once the trigger lock is released again, the spray gun is again ready for operation. This process requires a lot of time. It may be during the manual cleaning process that the coating material nozzle is damaged and has to be replaced by a new nozzle. In addition, it may be that the blocked coating material nozzle can no longer be cleaned manually and then likewise has to be replaced.
A satisfactory solution is not previously known from the prior art.
One object of the invention is to specify a reversible coating material nozzle for a spray gun for coating workpieces with coating material, the reversible coating material nozzle being designed such that it can be used to coat a workpiece and is also self-cleaning where necessary.
A further object of the invention is to be able to dismantle the coating material nozzle from the spray gun head and to be able to install it in the spray gun head without an additional tool, that is to say merely by hand, in spite of its small dimensions.
The coating material nozzle is advantageously easily removable from the spray gun and centres itself automatically during installation.
The object is achieved by a reversible coating material nozzle for a spray gun for coating workpieces with coating material having the features specified in patent claim 1.
The reversible coating material nozzle according to the invention for a spray gun for coating a workpiece with coating material is designed such that it can be installed in a first and a second installation position in a nozzle mount of the spray gun. It comprises a nozzle core with a nozzle core opening and a nozzle nipple connected to the nozzle core, the nozzle nipple having a nozzle nipple opening. In addition, a nozzle channel for the coating material is provided and reaches through the nozzle nipple and the nozzle core and connects the nozzle nipple opening to the nozzle core opening. The nozzle nipple has a cylindrical portion, which in the first installation position forms a form fit with the nozzle mount of the spray gun. In addition, a stop is provided. The ratio between the length from the stop to the cylindrical portion and the nozzle diameter lies in the range between 0.75 and 2.00.
Advantageous developments of the invention will emerge from the features specified in the dependent patent claims.
In an embodiment of the coating material nozzle according to the invention, the ratio between the length and the nozzle diameter lies in the range between 0.80 and 1.35.
In a further embodiment of the coating material nozzle according to the invention, the nozzle nipple has a cone, which in the first installation position forms a form fit with the nozzle mount of the spray gun. The nozzle core likewise has a cone, which in the second installation position forms a form fit with the nozzle mount.
In a development of the coating material nozzle according to the invention, the nozzle nipple is made of plastic. This has the advantage that the nozzle nipple can be produced from an economical material and can be produced by means of injection moulding.
In another development of the coating material nozzle according to the invention, the nozzle core is made of carbide metal or ceramic. The service life of the nozzle is thus extended. In addition, in this development, even abrasive coating material can be sprayed.
In an additional development of the coating material nozzle according to the invention, the nozzle nipple has a further cylindrical portion, which forms a form fit with the nozzle core. Tolerances during the production of this portion do not play a specific role. Even a potential material pressing is not critical or is even beneficial for the tightness.
In an embodiment of the coating material nozzle according to the invention, a seal is provided between the nozzle core and the nozzle nipple. The tightness between the nozzle nipple and the nozzle core can thus be increased, and it is possible to ensure that the coating material exits from the coating material nozzle exclusively through the nozzle core opening.
In a further embodiment of the coating material nozzle according to the invention, a nozzle holder is provided, which holds together the nozzle core and the nozzle nipple. In this embodiment, the nozzle nipple can also be produced from carbide metal or ceramic. The service life of the coating material nozzle can thus be further increased.
In a further embodiment of the coating material nozzle according to the invention, the nozzle holder is made of plastic. Such a coating material nozzle can be produced cost-effectively by means of injection moulding.
It is additionally proposed, with the coating material nozzle according to the invention, to form the connection between the nozzle holder and the nozzle nipple as a snap-fit connection. This likewise facilitates the production. The nozzle holder and the nozzle nipple can be interconnected however by adhesive bonding, welding or by a pressing process.
In the coating material nozzle according to the invention, the plastic may be electrically non-conductive. Such a coating material nozzle can be used in an electrostatic spray gun. As a result of the non-conductive plastic, the electrical charge of the high-voltage-carrying electrode at the spray gun head does not reach the housing of the spray gun. In addition, an inadmissible increase of the capacitance with respect to earth potential is thus avoided. A sudden discharge is prevented. In the case of an electrostatic spray gun, this additionally has the advantage that the electrical capacitance of the coating nozzle is reduced due to the lower fraction of metal. Since less electrical charge can thus be stored, the risk of a sudden discharge is reduced.
In an additional embodiment of the coating material nozzle according to the invention, a shoulder is provided which has a diameter of at least 5 mm and at most 15 mm and forms an axial stop.
In the coating material nozzle according to the invention, the nozzle nipple is advantageously an injection-moulded part, which surrounds the nozzle core in part. This embodiment is also cost effective and can be produced easily.
In addition, in the coating material nozzle according to the invention, the shoulder can be formed in such a way that it forms a form fit with an air cap of the spray gun in the installed state. If the air cap is rotated about its longitudinal axis, the coating material nozzle also rotates. This is advantageous in particular if the nozzle core opening is formed in a slit-shaped manner. The flat jet produced by the coating material nozzle can thus be rotated and adapted to the respective requirements during the coating process.
In a further embodiment of the coating material nozzle according to the invention, the lateral surface of the shoulder has a flat area. During the installation of the coating material nozzle, the flat area of the shoulder is aligned with the flat area of the air cap.
The spray gun according to the invention for coating a workpiece with coating material has a coating material nozzle which is formed as described above.
In the spray gun according to the invention, the nozzle mount may have a bore for receiving the nozzle nipple.
In addition, the spray gun may have a high-voltage electrode.
The coating material nozzle according to the invention can be used in a spray gun for coating a workpiece with coating material.
Lastly, a method for operating the above-described spray gun for coating a workpiece with coating material is proposed, in which the coating material nozzle is installed in the first installation position in the spray gun when the spray gun is to function in coating operation. If the spray gun is to function in cleaning operation, the coating material nozzle is installed in the second installation position in the spray gun.
The invention will be explained in greater detail hereinafter with a number of exemplary embodiments on the basis of six figures.
In addition, the spray gun head 6 comprises a nozzle protector 8, which is optional however. As a result of the nozzle protector, the risk of the operator coming directly into contact with the coating material at the nozzle outlet 24 of the coating material nozzle 20 (see
The coating material nozzle 20 is supplied via a material line 13. This is in turn connectable to a material tube (not shown in the figures) via a connection for coating material 3.
The spray gun 1 further has a connection for compressed air 4. The compressed air can be directed to the coating material jet as required by shaping air channels 11 and 12, which are located in the downstream region in an air cap 10 of the spray head 8. With the aid of the compressed air, the shape of the coating material jet can be adapted.
Furthermore, the spray gun 1 comprises an electric connection 5, via which an electrode 15 on the spray gun head 6 can be supplied with high voltage. The high voltage is used to ionise the coating material. A spray gun formed in this way will also be referred to hereinafter as an electrostatic gun.
In order to control the flow of coating material, the spray gun 1 also comprises a trigger guard 2. With actuation thereof, a valve arranged in the spray gun 1 is opened via a valve stem such that the coating material reaches the coating material nozzle 20 and is sprayed therethrough. With the aid of a trigger lock 16, the trigger guard 2 can be locked. In the locked state, the trigger guard 2 can no longer be actuated, such that no more coating material can be sprayed.
The nozzle holder 21 is designed such that it holds together the nozzle nipple 22 and the nozzle core 23. The connection between the nozzle holder 21 and the nozzle nipple 22 can be designed as a snap-fit connection 21.3, 22.3. To this end, the nozzle holder 21 has a resilient element or a catch 21.3, which engages in a groove 22.3 of the nozzle nipple 22.
The nozzle holder 21 can be produced from plastic. Such a coating material nozzle 20 can be produced cost-effectively by means of injection moulding.
The plastic, from which the nozzle holder 21 and/or the nozzle nipple 22 is/are produced, is preferably an electrically non-conductive plastic. Due to the non-conductive plastic, the electrical charge of the high-voltage-carrying electrode 15 on the spray gun head 6 does not reach the housing 14 of the spray gun 1. In addition, an inadmissible increase of the capacitance with respect to earth potential is thus avoided. A sudden discharge is prevented. Instead of plastic, another electrically non-conductive material may also be used. Such a coating material nozzle can be used in an electrostatic spray gun.
If the coating material nozzle is used for non-electrostatic applications, the plastic may also be electrically conductive, or metal can also be used instead of the plastic. Such a coating material nozzle can be used in a non-electrostatic spray gun. This coating material nozzle can also be used in an electrostatic spray gun if the spray gun is operated without electrostatics.
The nozzle holder 21 also comprises a shoulder 21.5, which serves as an axial stop. It extends between the heel 21.8 and the heel 21.7. In the region of the shoulder 21.5, the coating material nozzle 20 preferably has an outer diameter D of at least 5 mm and at most 15 mm. In a preferred embodiment, the outer diameter D is 11 mm. The shoulder 21.5 is positioned with respect to the cone 23.1 of the nozzle core 23 and the cone 22.1 of the nozzle nipple 22 in the axial direction such that the dimensions L1 and L2 are approximately of identical size. The dimension L1 is defined as the distance between the heel 21.8 and the cone 23.1. The dimension L2 is defined as the distance between the heel 21.7 and the cone 22.1. The ability to install the coating material nozzle 20 both in the first installation position and in the second installation position is thus improved.
In the first installation position, the heel 21.7 forms an axial stop on the shoulder 21.5. If the cap nut 7 is screwed onto the housing 14 of the spray gun, the cap nut 7 via the axial stop 21.7 pushes the cone 22.1 of the coating material nozzle 20 onto the nozzle mount 9.
In the second installation position, the other heel 21.8 of the shoulder 21.5 forms an axial stop. If the cap nut 7 is screwed onto the housing 14 of the spray gun, the cap nut 7 via the axial stop 21.8 pushes the cone 23.1 of the nozzle core 23 onto the nozzle mount 9.
The coating material channel 26 reaches through the nozzle nipple 22 and the nozzle core 23 and connects the nozzle nipple opening 25 to the nozzle core opening 24.
In order to increase the tightness between the nozzle nipple 22 and the nozzle core 23, a seal (not shown in the figures) can be provided between the nozzle core 22 and the nozzle nipple 23. The seal can be formed as an axial seal, for example as an O-ring.
As shown in
The coating material nozzle 20 has a length L in the range from 10.0 mm to 14.6 mm and preferably of 12.3 mm. The nozzle diameter is preferably 11 mm. The dimensions of the coating material nozzle 20 are relatively small, however it can still be grasped by hand.
These dimensions give a ratio between the length L and the nozzle diameter D from 0.91 to 1.33. A ratio of L/D in the region from 0.75≦L/D≦2 can still be tolerated. The length L and the nozzle diameter D are preferably matched to one another such that the ratio L/D is 1.12. With this ratio of L/D, the coating material nozzle 20 can be installed optimally in the spray gun head 6. If the ratio L/D lies outside the above-specified region, the coating material nozzle 20 may tilt both during disassembly and during installation in the spray gun head 6, such that the installation or disassembly without an additional tool is then only still possible with difficulty, if at all, and requires a relatively large amount of time and a relatively large amount of patience.
The nozzle nipple 32 comprises a shoulder 32.5, which serves as an axial stop. It is located approximately in the middle of the coating material nozzle 30 and reaches from the heel 32.8 to the heel 32.7. In the region of the shoulder 32.5, the coating material nozzle 30 preferably has an outer diameter of at least 5 mm and at most 15 mm.
In the first installation position, the heel 32.7 on the shoulder 32.5 forms an axial stop. If the cap nut 7 is screwed onto the housing 14 of the spray gun, the cap nut 7 via the axial stop 32.7 pushes the cone 32.1 of the coating material nozzle 30 onto the nozzle mount 9.
In the second installation position, the other heel 32.8 of the shoulder 32.5 forms an axial stop. If the cap nut 7 is screwed onto the housing 14 of the spray gun, the cap nut 7 via the axial stop 32.8 pushes the cone 33.1 of the nozzle core 33 onto the nozzle mount 9 (see also
The coating material nozzle 30 has a length L in the range from 7.3 mm to 11.3 mm and preferably of 9.3 mm. The nozzle diameter D is preferably 9 mm. The dimensions of the coating material nozzle 30 are also relatively small, however they can still be grasped by hand.
These dimensions give a ratio between the length L and the nozzle diameter D from 0.81 to 1.26. A ratio of L/D in the range from 0.75≦L/D≦2 can still be tolerated. The length L and the nozzle diameter D are preferably matched to one another such that the ratio L/D is 1.03. With this ratio of L/D, the coating material nozzle 20 can be installed optimally in the spray gun head 6. If the ratio L/D lies outside the above-specified range, the coating material nozzle 30, as already mentioned, may tilt both during disassembly and during installation in the spray gun head 6, such that the installation or disassembly without additional tools is then only possible with difficulty, if at all, and requires a relatively large amount of time and a relatively large amount of patience.
The material from which the nozzle nipple 32 is produced is preferably electrically non-conductive. The electrical charge of the high-voltage-carrying electrode 15 on the spray gun head 6 therefore does not reach the housing 14 of the spray gun 1. In addition, an inadmissible increase in the capacitance with respect to earth potential is thus avoided. A sudden discharge is prevented. The nozzle nipple 32 therefore provides the electrical insulation between the high-voltage-carrying components and the generally earthed components of the spray gun 1. Such a coating material nozzle can be used in an electrostatic spray gun.
The nozzle nipple 32 may be an injection-moulded part, which surrounds the nozzle core 33 in part. This embodiment is also cost-effective and can be produced easily.
The tightness between the nozzle nipple 32 and the nozzle core 33, as shown in
In order to increase the tightness between the nozzle nipple 32 and the nozzle core 33, a seal (not shown in
The cylindrical portions 22.4 and 22.5 and also 32.4 and 32.9 of the nozzle nipples 22 and 32 respectively additionally have the advantage that they are not susceptible to tolerances and material pressing.
The nozzle cores 23 and 33 can be made of hard metal or ceramic. The service life of the coating material nozzles 20 and 30 is thus extended. In addition, even abrasive coating material can be sprayed using such coating material nozzles without resulting in excessive wear.
The nozzle nipples 22 and 32 can also be produced from carbide metal or ceramic. The service times of the coating material nozzles 20 and 30 can thus be increased further still.
The angles α, β and γ (see
The shoulder 21.5 or 32.5 can be designed both in the case of the coating material nozzle 20 and in the case of the coating material nozzle 30 in such a way that it forms a form fit with the air cap 10 of the spray gun 1. If the air cap 10 is rotated about its longitudinal axis, the coating material nozzle 20 or 30 also rotates. This is advantageous in particular if the nozzle core opening 24 is formed in a slit-shaped manner. The flat jet produced by the coating material nozzle 20 or 30 can thus be rotated and adapted to the respective requirements during the coating process. To this end, as shown in
If the coating material nozzle 20 or 30 is installed in the first installation position in the spray gun, the spray gun 1 functions in coating operation, such that workpieces can be coated. If the coating material nozzle 20 or 30 of the spray gun 1 by contrast is to be cleaned, the coating material nozzle is installed in the second installation position in the spray gun 1.
In a further embodiment of the coating material nozzle, the two angles α and β of the cones 22.1 and 23.1 of the coating material nozzle 20 or the two angles α and β of the cones 32.1 and 33.1 of the coating material nozzle 30 may be of approximately identical size.
The coating material nozzle according to the invention can also be used in a spray gun without compressed air assistance. In the case of such a spray gun, the compressed air connection 4 is absent.
The coating material nozzle according to the invention can also be used in an automatic spray gun. An automatic spray gun is understood to mean a spray gun that is not held by hand, but for example is secured or fixedly installed on a robot or a linear guide.
The above description of the exemplary embodiments according to the present invention is provided merely for illustrative purposes and not for the purpose of limiting the invention. Different amendments and modifications are possible within the scope of the invention without departing from the scope of the invention and equivalents thereof. For example, the different coating material nozzles shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 1140524 | Apr 2011 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CH2012/000078 | 4/3/2012 | WO | 00 | 10/2/2013 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2012/135966 | 10/11/2012 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3563463 | Walker | Feb 1971 | A |
| 4074857 | Calder | Feb 1978 | A |
| 4157163 | Pinto et al. | Jun 1979 | A |
| 5190224 | Hamilton | Mar 1993 | A |
| 5820025 | Troudt | Oct 1998 | A |
| 6390386 | Krohn et al. | May 2002 | B2 |
| 20030006322 | Hartle et al. | Jan 2003 | A1 |
| 20030098369 | Foster et al. | May 2003 | A1 |
| 20040195354 | Leisi | Oct 2004 | A1 |
| 20050082257 | Bierings et al. | Apr 2005 | A1 |
| 20050224602 | Foubert et al. | Oct 2005 | A1 |
| Number | Date | Country |
|---|---|---|
| 298 01 651 | May 1999 | DE |
| Entry |
|---|
| International Search Report for corresponding International Application No. PCTCH2012/000078 mailed Sep. 17, 2012. |
| Number | Date | Country | |
|---|---|---|---|
| 20140044881 A1 | Feb 2014 | US |
