AU2004203520B2

AU2004203520B2 - Spray coating device

Info

Publication number: AU2004203520B2
Application number: AU2004203520A
Authority: AU
Inventors: Thomas Scholz
Original assignee: ITW Oberflaechentechnik GmbH
Current assignee: Carlisle Fluid Technologies Germany GmbH
Priority date: 2003-08-02
Filing date: 2004-07-30
Publication date: 2006-06-15
Anticipated expiration: 2024-07-30
Also published as: CN1623675A; DE502004000291D1; EP1504823A1; EP1504823B1; DE10335420A1; JP2005052830A; AU2004203520A1

Description

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Name of Applicant: ITW Oberflachentechnik GmbH Co. KG Actual Inventor(s): Thomas Scholz Address for Service and Correspondence: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: SPRAY COATING DEVICE Our Ref 724281 POF Code: 1559/461117 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): -1- 6006q la SPRAY COATING EQUIPMENT The invention concerns spray coating equipment to coat objects by spraying.

The coating material may be a liquid, e.g. paint, in particular varnish, or a coating powder, that is sprayed on the object to be coated and afterwards is permanently bonded with the object by heat treatment. The spraying equipment can be a hand-held spray gun or an automatic spray gun held by a machine.

From the printed patent specification DE 34 02 945 C2 (corresponds to GB 2 153 260 A) an electrostatic hand-held spray gun is disclosed for the spray coating of objects, which has at least one high-voltage electrode to electrostatically charge the coating material. On the spray gun a voltage indicating instrument is provided with a rearward facing display field to display an optical signal as the function of the prevailing voltage of the high-voltage electrode. The spray gun may be designed for the spraying of coating powder or to coat by using coating liquid. The rearward facing display field of the voltage indicating instrument can be observed during the spray coating operation by a person holding the spray gun without the need to look away from the object to be coated by the spray jet. The document describes an embodiment, wherein the voltage indicating instrument is connected to a highvoltage generator that is located in the spray gun. A light emitting diode is connected via an electric resistance to the primary side of a transformer, to the secondary side of which a cascade circuit is connected to generate a highvoltage DC for the high-voltage electrode. The transformer and the light emitting diode are situated in a transformer housing, that is provided on the spray gun and is detachably fastened on the spray gun. A rapid separation of the transformer housing from the spray gun is, however, not possible because of the electric leads, by which the transformer, accommodated in the transformer housing, is connected to the cascade circuit positioned in the spray gun. Instead of the light emitting diode the voltage indicating instrument may have a incandescent lamp, a volt meter or a similar voltage-dependent optical indicating instrument. The accommodation of a high-voltage generator in the spray gun, with or without the high-voltage transformer on or in the spray gun, W:\DELILAH\ABM\IRN724281.RETYPED PAGES.doc 2 has the advantage that to supply the electric energy from a control unit to the spray gun not a high-voltage cable, but a low-voltage cable is required, that is considerably lighter and less rigid than a high-voltage cable. Before integrating a high-voltage generator in a spray gun the high-voltage generator was accommodated in the control unit, what is still possible nowadays, but normally is not done. Usually nowadays a low-voltage DC is supplied from the control unit to the spray gun via a low-voltage lead, and transformed to a high-voltage DC in the range of between 4000 V to 140000 V or higher by a high-voltage generator accommodated in the spray gun.

Small changes of the high-voltage value, the high-voltage electron current flowing through the electrode, and/or the quantity of coating material fed per unit of time, and/or the quantity of compressed air fed per unit of time, to vaporise the coating material or to form the spray jet for the coating material, and/or changes in the air pressure, for example, may already lead to a deterioration of the quality of the coating. Therefore a person should constantly observe the spray jet being sprayed and the object to be coated. In the case of the prior art mentioned above, the voltage indicator supports the person inasmuch that he commences the spraying operation by pressing the button on the spray gun only after the high-voltage is switched on, and that by releasing the button of the spray gun the person terminates the spraying operation immediately when the high-voltage drops or falls below a certain minimum value. The person can see the actual prevailing voltage when the voltage indicating instrument contains a volt meter instead of light emitting diodes.

It is an advantage, however, when the operator obtains additional operational information related to the coating, e.g. the nominal value of the high-voltage electrode current, the actual value of the high-voltage electrode current, the maximum permissible high-voltage limit value, to keep the operating mode highvoltage constant and/or the operating mode high-voltage electrode current constant without the necessity for the operator to move his/her head away from the spray jet or the object to be coated, for example away from the direction towards the object to be coated to the control unit, on which the operational W:\DELILAHf\ABM\IRN724281.RETYPED PAGESdOC parameters can be adjusted and which is usually provided with indicating instruments for the information mentioned above.

The disadvantage of an indicating instrument, permanently joined with the spraying equipment or the disconnection of which from it requires a long time, is that the spraying equipment has to be occasionally cleaned with a cleaning agent, a solvent for example, while the indicating instrument is not cleaning agent-proof or solvent-proof. A further disadvantage is that in the case of a faulty indicating instrument a replacement of the instrument is expensive, or, if the indicating instrument is undetachably joined with the spraying equipment, the entire spraying equipment has to be replaced. Another further disadvantage is, that when coating the rear sides or hollow spaces of the objects to be coated, the spraying equipment has to be moved very close to or into the object, and consequently the sprayed coating material settles on the indicating instrument. In such a case it would be advantageous not to provide the indicating instrument on the spraying equipment, but separately from it, yet still in the vicinity of the operator, where the indicating instrument can be observed by the operator, without the necessity to turn or appreciably turn his head away from the spray jet or the object to be coated so that he could observe the spray jet and the object to be coated as well as the display field of the indicating instrument. In such a case it could be, for example, advantageous to arrange the indicating instrument on the object to be coated or on a support provided behind or directly next to the object to be coated.

It would be desirable to construct the spray coating equipment in such a manner, that the location, operational capability, cleaning conditions and service life of the spraying equipment is independent from the indicating instrument, while the position of the indicating instrument is also independent from the control unit and consequently can be so positioned, that its display field can be observed by a person, whose face is directed directly or at an angle towards the spray jet or the object to be coated, that object being situated in the spray jet.

The discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the DELILAHABM\IRN724281.RETYPED PAGES.doc present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia before the priority date of each claim of this application.

According to the present invention, there is provided spray coating equipment, including a control unit, by which electric energy can be supplied via an electric lead to an electric spraying device, for spraying coating material on an object to be coated and which has at least one high-voltage electrode for the electrostatic charging of the coating material by means of high-voltage; wherein the control unit is designed to adjust at least one parameter of the coating operation; and including at least one optical indicating instrument for optical display of at least one information relating to the coating operation, wherein the indicating instrument can be positioned externally from the control unit, wherein the control unit includes a transmitter for wireless data transfer of the at least one information regarding the coating operation and the indicating instrument includes a receiver for the wireless data reception of the at least one information regarding the coating operation.

The following advantages can result from this: the spraying equipment, the indicating instrument and the control unit can be positioned, operated and cleaned independently from one another. The indicating instrument can be positioned anywhere where it does not get soiled or does not hinder the use of the spraying equipment or of the control unit. If the spraying equipment or the control unit become defective, the indicating instrument may not need to be replaced or dismantled, and in the case of a defective indicating instrument the spraying equipment or the control unit may not need to be replaced or dismantled. This can provide cost-effective feasible alternatives. When compared with data transfer via cables, e.g. electric leads, the wireless data transfer has the advantages that any distance between the individual parts can be set without the necessity of cables having various lengths; that the individual parts can be positioned with great variations, and also at places where no cables could otherwise be used; no data transmission cable, that would require cleaning, exists; cost saving.

W:\DELILAH ABM\IRN724281-RETYPED PAGES.doc In the following description the invention is described, based on preferred embodiments with reference to the attached drawings. The drawings show in: Fig.1 a preferred embodiment of a spray coating equipment according to the invention, schematically and not to scale, Fig.2 a further embodiment of a spray coating equipment according to the invention, schematically and not to scale, Fig.3 a rear view of a spray gun with an indicating instrument detachably fastened thereon, according to a special embodiment of the invention.

Fig.1 shows an electronic control unit 2 and an electrostatic spray gun 4, that can be carried manually by a person 6 and can be switched on and off by actuating a trigger 8 to spray coating material in the form of a spray jet 10 onto an object 11 to be coated.

At one end the control unit 2 has a mains connection 12 and at the other it is connected via a current cable 14 to the spray gun 4 to supply electric energy to at least one high-voltage electrode 15, to generate on the high-voltage electrode 15 an electric high-voltage potential in the range of 1000-160000 V relative to the earth potential, so that to electrostatically charge the coating material and to produce an electro-magnetic field between the at least one highvoltage electrode 15 and the object 11 to be coated. The control unit 2 is preferably so constructed, that on the high-voltage electrode 15 not just one single high-voltage value but various high-voltage values can be selectively set by means of the operating element 16. The control unit 2 has preferably a light 18, that with the high-voltage switched on lights up and with the high-voltage switched off is unlit, and/or an indicating instrument 20, on which at least one information, e.g. the set nominal high-voltage value and/or the actual highvoltage value, and/or the nominal current and/or the actual current of the highvoltage electrode 15 can be optically displayed.

W:\DELILAHIBM\IRN724281-RETYPED PAGES.doc 6 The spray gun 4 is connected to a coating material conveying device 24 via a coating material hose 22 for the purpose of supplying the coating material from a reservoir 26 to the spray gun 4 and through this for vapourising in a spray head 28 of the spray gun 4, so that the spray jet 10 is produced. By means of the conveying device 24 preferably not only a constant quantity of coating material can be conveyed per unit of time, but the conveyed quantity per unit of time can be preferably be adjusted on the control unit 2 via a control lead 25 by, for example, by automatic control or manually via an operating element 28. On the same indicating instrument or preferably on another indicating instrument of the control unit 2 at least one information can be optically displayed regarding the coating material, e.g. a parameter, e.g. a nominal value of the conveyed quantity of the coating material per unit of time, or an actual value of the conveyed quantity, or a value depending on the relevant values.

Various types of conveying devices 24 may be used: a) a compressed air equipment, that produces excess pressure in the reservoir 26, thus pressing the coating liquid into the hose 22; b) a liquid pump; or c) in case of coating powder an injector for the pneumatic transporting of the powder, as it is known from the state-of-the-art.

The description of the embodiment of Fig.1 applies without limitation also to the embodiment shown in Fig.2. The difference between the two embodiments is that in the case of the embodiment according to Fig.1 the control unit 2 comprises a high-voltage generator 32, so that the high-voltage is transmitted via the electric lead cable 14 to the at least one electrode 15 of the spray gun 4, whereas in the case of the embodiment according to Fig.2, that is the embodiment preferred to that of Fig.l, the control unit 2 does not comprise a high-voltage generator 32, but a voltage transformer 34, that produces from the mains voltage of the mains connection 12 a lower voltage, preferably a DC of 12 or 24 V, for example, that is conveyed via a low-voltage cable 35 to a highvoltage generator 36 accommodated in the spray gun 4. In this case the at least one high-voltage electrode 15 is connected to the high-voltage side of the highvoltage generator 36.

WADELIL4ABMIRN72428l -RETYPED PAGES.doc In the case of both coating devices according to Figs.1 and 2, instead of or additionally to the indicating instruments 20 and/or 30, for example, of the control unit 2, at least one indicating instrument 40 is provided, that is external to the control unit 2 and optically indicates at least one information relevant for the coating operation with regard to the high-voltage or the coating material or both. These information are preferably the same that have been mentioned above regarding the indicating instruments 20 and 30 of the control unit 2. The control unit 2 comprises a transmitter 42 for the wireless data transfer of at least one information regarding the coating operation and the external indicating instrument 40, spatially independent from the control unit 2, comprises a receiver 44 for the wireless data reception of at least one information regarding the coating operation of the control unit 2. In the drawings the transmitter 42 and the receiver 44 are schematically represented as antennae which protrude from the respective equipment, however, they are preferably fully integrated into the control unit 2 and into the external indicating instrument By virtue of this, the information relevant for the coating operation can be displayed to the person 6 instead of on the indicating instruments 20 and/or of the control unit, or additionally to them, on the indicating instrument 40. The external indicating instrument 40, that transmits signals in a wireless manner, is preferably so constructed, that it does not need any external energy supply for its operation, a mains connection, for example. The energy, required to operate the external indicating instrument 40 may come from an external or internal power source, e.g. a battery or an accumulator that can be inserted into the external indicating instrument 40, or preferably from the spraying equipment, e.g. the spray gun 4, or, for example, via electric contacts, of which at least one can be provided on the spray equipment and at least one other on the indicating instrument and the two can be brought into contact with one another.

Of all the information relevant for the spray coating operation at least one can be optically displayed on an external indicating instrument 40. Such information are, for example, high-voltage switched on, high-voltage switched off, nominal high-voltage value, actual high-voltage value, nominal value of high-voltage electrode current, actual value of high-voltage electrode current, maximum W:\DELILAH\ABMXIRN724281-RETYPED PAGES.doc permissible high-voltage limit value, to keep the operating mode high-voltage constant and/or the operating mode high-voltage electrode current constant.

The display field 46 of the external indicating instrument 40 is preferably a flat display screen according to one of the technologies: plasma display panel (PDP), vacuum fluorescence display panel (VFD), light emitting diodes panel (LED) or liquid crystal diode panel (LCD).

The external indicating instrument 40 has preferably a first rapid fastening means, with which it can be fastened rapidly and released many times on a second rapid fastening means. This may be a hook and loop-type fastener that can be inserted into one another or locked within one another, or clamped on one another or suspended on one another or a zip fastener that can be fastened on one another.

The second rapid fastening means can be fastened on the spray gun or built on it or on another support. The other support may be the object to be coated itself, or an element that is arranged behind or next to the object to be coated or on the spray gun 4, for example a support device, that carries also the object to be coated. Both rapid fastening means can have contacts to transfer electric energy to the indicating instrument Another embodiment provides, that only the spray gun is provided with a fastening means to fasten it on a support, while this fastening means may be a hook, a tape or a chain or another means that can be fastened on the spray gun or on another support, without the spray gun or the other support also having fastening means. The fastening means can be a tape or a ring, that, for example, envelopes the spray gun or another support so that to be held on it.

According to another embodiment of the invention an arm band or an arm ring may be fastened on the external indicating instrument 40, with which the indicating instrument can be fastened on the arm of a person.

W:\DELILAH ABM\lRN724281 -RETYPED PAGES.doc The external indicating instrument 40 is so positioned, that its display field 46 is directly in the front of or obliquely in front of the face of a person 6, who is facing the spray jet 10 or the object 11 to be coated, that is situated in the spraying range of the spray gun 4.

Fig.3 shows the rear of the spray gun 4 together with the external indicating instrument 40 fastened thereon. On its underside the external indicating instrument 40 has a rapid fastening means 50, for example in the form of a plug-in device, that can be connected with a second rapid fastening means 52, for example in the form of a plug-in device, that is formed or fastened on the upper side of the spray gun 4. The two mating rapid fastening means 50, 52 may be, for example, a groove-and-tongue connection, for example with a dove-tail cross-section.

The external indicating instrument 40 may have one or several display fields 46 or one or several information may be displayed in the display field 46.

In addition to hand-held spray guns the invention also comprises automatic spraying equipment.

All features and combinations of two or more features of the description and of the claims as well of the drawings are features which can be used individually on their own or in the relevant combination and are advantageous, independently from the extent of protection of the patent claims.

Throughout the description and claims of this specification the word "comprise" and variations of that word, such as "comprises" and "comprising", are not intended to exclude other additives or components or integers.

W:\DELILAH\ABM\IRN72428l-RETYPED PAGESdoc

Claims

1. Spray coating equipment, including a control unit, by which electric energy can be supplied via an electric lead to an electric spraying device, for spraying coating material on an object to be coated and which has at least one high-voltage electrode for the electrostatic charging of the coating material by means of high-voltage; wherein the control unit is designed to adjust at least one parameter of the coating operation; and including at least one optical indicating instrument for optical display of at least one information relating to the coating operation, wherein the indicating instrument can be positioned externally from the control unit, wherein the control unit includes a transmitter for wireless data transfer of the at least one information regarding the coating operation and the indicating instrument includes a receiver for the wireless data reception of the at least one information regarding the coating operation.

2. Spray coating equipment according to claim 1, wherein the control unit and the indicating instrument are designed for wireless data transmission of at least one of the following information: high-voltage switched on, high-voltage switched off, nominal high-voltage value, actual high-voltage value, nominal value of high-voltage electrode current, actual value of high-voltage electrode current, maximum permissible high-voltage electrode current limit value and/or to keep the operating mode high- voltage constant or the operating mode high-voltage electrode current constant.

3. Spray coating equipment according to claim 1, wherein the control unit and the indicating instrument are designed for wireless data transmission and optical display of at least two of the following information regarding the coating operation: high-voltage switched on, high-voltage switched off, nominal high-voltage value, actual high-voltage value, nominal value of high-voltage electrode current, actual value of high-voltage electrode W:1DELILAHABMIRN724281.RETYPED PAGES.doc 11 current, maximum permissible high-voltage electrode current limit value and/or to keep the operating mode high-voltage constant or the operating mode high-voltage electrode current constant.

4. Spray coating equipment according to any one of the preceding claims, wherein the at least one indicating instrument to display the at least one information has a flat display screen according to one of the technologies: plasma display panel (PDP), vacuum fluorescence display panel (VFD), light emitting diodes panel (LED) or liquid crystal diode panel (LCD). Spray coating equipment according to any one of the preceding claims, wherein the at least one indicating instrument has a first rapid fastening means, with which it can be fastened rapidly and released many times on a second rapid fastening means, while the second rapid fastening means is fastened or formed on a support.

6. Spray coating equipment according to claim 5, wherein the two rapid fastening means are clamping means which can be inserted into one another or locked within one another, or a hook and loop-type fastener that can be fastened on one another or a zip fastener that can be fastened on one another and/or hooks or means accommodating hooks for suspension.

7. Spray coating equipment according to claim 5 or 6, wherein the second rapid fastening means is fastened or built on the spray equipment.

8. Spray coating equipment according to any one of claims 1 to 4, wherein the at least one indicating instrument is fitted with a rapid fastening means for the rapid and detachable fastening on a support.

9. -Spray coating equipment according to claim 8, wherein the at least one indicating instrument is fitted with a rapid fastening means for the fastening on the spray equipment. W:\DELILAH\ABM\IRN724281-RETYPED PAGES.doc I Spray coating equipment according to claim 8 or 9, wherein the rapid fastening means has a plug-in device, a clamping device, a hook or an erectable ring.

11. Spray coating equipment according to any one of claims 1 to 4, wherein the at least one instrument is provided with an arm band or an arm for the fastening of the indicating instrument on the arm of a person.

12. Spray coating equipment according to any one of the preceding claims, wherein the spray equipment is a hand-held spray gun.

13. A spray coating equipment substantially as herein described with reference to the accompanying drawings. DATED: 29 July, 2004 PHILLIPS ORMONDE FITZPATRICK Attorneys for: ITW Oberflachentechf W:\DELILAH\ABM\RN724281-RETYPED PAGES.doc