Patent Application
20060283386
This invention relates to hand-held, electrostatically-aided coating atomizing and dispensing equipment (hereinafter sometimes electrostatic spray guns, or simply guns). However, it is believed to be useful in other applications as well.
A great number of spray guns are known. Among configurations of interest are the configurations illustrated and described in the following listed U.S. Patents and published applications: 2003/0006322; 6,712,292; 6,698,670; 6,669,112; 6,572,029; 6,460,787; 6,402,058; RE36,378; 6,276,616; 6,189,809; 6,179,223; 5,836,517; 5,829,679; 5,803,313; RE35,769; 5,639,027; 5,618,001; 5,582,350; 5,553,788; 5,400,971; 5,395,054; D349,5.59; 5,351,887; 5,332,159; 5,332,156; 5,330,108; 5,303,865; 5,299,740; 5,289,974; 5,284,301; 5,284,299; 5,236,129; 5,209,405; 5,209,365; 5,178,330; 5,119,992; 5,118,080; 5,180,1.04; D325,241; 5,090,623; 5,074,466; 5,064,119; 5,054,687; D318,712; 5,022,590; 4,993,645; 4,934,607; 4,934,603; 4,927,079; 4,911,367; D305,453; D305,452; D305,057; D303,139; 4,844,342; 4,770,117; 4,760,962; 4,759,502; 4,747,546; 4,702,420; 4,613,082; 4,606,501; D287,266; 4,537,357; 4,529,131; 4,513,913; 4,483,483; 4,453,670; 4,437,614; 4,433,812; 4,401,268; 4,361,283; D270,368; D270,367; D270,180; D270,179; RE30,968; 4,331,298; 4,248,386; 4,214,709; 4,174,071; 4,174,070; 4,169,545; 4,165,022; D252,097; 4,133,483; 4,116,364; 4,114,564; 4,105,164; 4,081,904; 4,037,561; 4,030,857; 4,002,777; 4,001,935; 3,990,609; 3,964,683; and, 3,940,061. Reference is here also made to U.S. Pat. Nos. 6,562,137; 6,423,142; 6,144,570; 5,978,244; 5,159,544; 4,745,520; 4,485,427; 4,481,557; 4,324,812; 4,187,527; 4,075,677; 3,894,272; 3,875,892; and, 3,851,618. The disclosures of these references are hereby incorporated herein by reference. This listing is not intended to be a representation that a complete search of all relevant art has been made, or that no more pertinent art than that listed exists, or that the listed art is material to patentability. Nor should any such representation be inferred.
According to one aspect of the invention, an apparatus for electrostatically aided atomization and dispensing of coating material includes a power supply for supplying operating potential and a coating dispensing device remote from the power supply. The coating dispensing device includes an input/output (I/O) device. The I/O device includes at least one indicator for selectively indicating a commanded state of the power supply and a fault state of at least one of the power supply and the coating dispensing device. A pair of conductors are provided for coupling commands from the I/O device to the power supply, for coupling commanded state information from the power supply to the I/O device, and for coupling fault state information from the power supply to the I/O device.
Illustratively according to this aspect of the invention, the power supply includes a controller. The pair of conductors couple the I/O device to the controller to couple commands from the I/O device to the controller and to receive from the controller commanded state information and fault state information.
Illustratively according to this aspect of the invention, the controller includes an input port for coupling to one of the pair of conductors for receiving commands from the I/O device and an output port for coupling to said one of the pair of conductors for coupling commanded state information from the power supply to the I/O device, and for coupling fault state information from the power supply to the I/O device.
Illustratively according to this aspect of the invention, the input port comprises an input port to an analog-to-digital (A/D) converter provided in the controller.
Further illustratively according to this aspect of the invention, the apparatus includes a digital-to-analog (D/A) converter. The output port is coupled to said one of the pair of conductors through the D/A converter.
Further illustratively according to this aspect of the invention, the apparatus includes a current source. The output port is coupled to said one of the pair of conductors through the current source.
Illustratively according to this aspect of the invention, the power supply includes a controller. The pair of conductors couple the I/O device to the controller to couple commands from the I/O device to the controller and to receive from the controller commanded state information and fault state information.
Illustratively according to this aspect of the invention, the power supply includes a first terminal at which the power supply provides a regulated output voltage and the coating dispensing device includes a second terminal coupled to the first terminal. The regulated output voltage varies in response to the commands from the I/O device.
Illustratively according to this aspect of the invention, the regulated output voltage comprises a selectively variable, relatively lower magnitude, direct current (DC) voltage. The coating dispensing device includes an inverter and a multiplier for multiplying the regulated output voltage to a relatively higher magnitude DC voltage at an output electrode of the coating dispensing device.
Illustratively according to this aspect of the invention, the I/O device includes at least one indicator for providing a visual indication of at least one of commands coupled from the I/O device to the power supply, commanded state information coupled from the power supply to the I/O device, and fault state information coupled from the power supply to the I/O device.
Illustratively according to this aspect of the invention, the I/O device further includes a first switch for commanding the power supply to occupy a state.
Illustratively according to this aspect of the invention, the at least one indicator comprises at least one indicator for each state the power supply can occupy and a second switch for each state the power supply can occupy.
Illustratively according to this aspect of the invention, the at least one indicator for each state the power supply can occupy comprises at least one light emitting diode (LED) for each state the power supply can occupy and the second switch for each state the power supply can occupy comprises a separate Zener diode having a Zener voltage corresponding to each separate state the power supply can occupy.
Illustratively according to this aspect of the invention, each indicator is coupled in series circuit with a respective second switch, forming an indicator/second switch series circuit. The indicator/second switch series circuits are in parallel with each other. The first switch is coupled in parallel with the parallel-coupled indicator/second switch series circuits.
According to another aspect of the invention, a method is provided for controlling an apparatus for electrostatically aided atomization and dispensing of coating material. The apparatus includes a power supply for supplying operating potential and a coating dispensing device remote from the power supply. The coating dispensing device includes an input/output (I/O) device. The I/O device includes at least one indicator for selectively indicating a commanded state of the power supply and a fault state of at least one of the power supply and the coating dispensing device. The method includes providing a pair of conductors coupling the I/O device to the power supply, coupling commands from the I/O device to the power supply, coupling commanded state information from the power supply to the I/O device, and coupling fault state information from the power supply to the I/O device.
Illustratively according to this aspect of the invention, coupling commands from the I/O device to the power supply through the pair of conductors includes coupling commands from the I/O device to a controller in the power supply through the pair of conductors. Coupling commanded state information from the power supply to the I/O device and coupling fault state information from the power supply to the I/O device comprise coupling the controller to the I/O device through the pair of conductors.
Further illustratively according to this aspect of the invention, the method includes providing on the controller an input port and an output port. Coupling commands from the I/O device to the controller includes coupling the input port to one of the pair of conductors. Coupling commanded state information from the power supply to the I/O device and coupling fault state information from the power supply to the I/O device comprise coupling the output port to said one of the pair of conductors.
Further illustratively according to this aspect of the invention, the method includes providing on the power supply a first terminal, providing at the first terminal a regulated output voltage, providing on the coating dispensing device a second terminal, coupling the second terminal to the first terminal, and varying the regulated output voltage in response to the commands from the I/O device.
Illustratively according to this aspect of the invention, providing a regulated output voltage comprises providing a selectively variable, relatively lower magnitude, direct current (DC) voltage, providing on the coating dispensing device an inverter and a multiplier, and multiplying the regulated output voltage to a relatively higher magnitude DC voltage at an output electrode of the coating dispensing device.
Further illustratively according to this aspect of the invention, the method includes providing on the I/O device at least one indicator for providing a visual indication of at least one of commands coupled from the I/O device to the power supply, commanded state information coupled from the power supply to the I/O device, and fault state information coupled from the power supply to the I/O device.
Further illustratively according to this aspect of the invention, the method includes providing on the I/O device a first switch for commanding the power supply to occupy a state.
Illustratively according to this aspect of the invention, providing on the I/O device at least one indicator comprises providing on the I/O device at least one indicator for each state the power supply can occupy and a second switch for each state the power supply can occupy.
Illustratively according to this aspect of the invention, providing on the I/O device at least one indicator for each state the power supply can occupy comprises providing on the I/O device at least one light emitting diode (LED) for each state the power supply can occupy. Providing on the I/O device the second switch for each state the power supply can occupy comprises providing on the I/O device a separate Zener diode having a Zener voltage corresponding to each separate state the power supply can occupy.
The invention may best be understood by referring to the following detailed description and accompanying drawings which illustrate the invention. In the drawings:
a-c illustrate a partly block and partly schematic diagram of a power supply for an electrostatic spray gun constructed according to the invention;
a-c illustrate a side elevational view, a plan view and an end view, respectively, of certain components illustrated schematically in
In the detailed descriptions that follow, several integrated circuits (hereinafter sometimes ICs) and other components are identified, with particular component values, circuit types and sources. In many cases, terminal names and pin numbers for specifically identified circuit types and sources are noted. This should not be interpreted to mean that the identified component values and circuits are the only component values and circuits available from the same, or any, sources that will perform the described functions. Other components and circuits are typically available from the same, and other, sources which will perform the described functions. The terminal names and pin numbers of such other circuits may or may not be the same as those indicated for the specific circuits identified in this application.
Referring now particularly to
Oscillator circuit 104 illustratively includes a low power monostable/astable multivibrator IC, such as, for example, a Fairchild CD4047BCM IC having C, R, RCCommon, notASTable, ASTable, − (negative) TRiGger, VSS, + (positive) TRiGger, eXtemaIREset, Q, notQ, ReTriGger, OSCillator output, and VDD terminals, pins 1-14, respectively. A 100 pF capacitor is coupled across the C and RCC terminals. A 13 KΩ resistor and 100 KΩ potentiometer in series are coupled across the R and RCC terminals. The notAST, AST and -TRIG terminals are coupled to 5 VDC supply. The VSS, +TRIG, XRE and RTG terminals are coupled to ground. The OSC terminal is coupled through a 100 KΩ resistor to 5 VDC. The VDD terminal is coupled to 5 VDC, and through a 100 nF capacitor to ground. The cathode of a 6.7 V Zener diode is coupled to the VDD terminal and its anode is coupled to ground.
Driver circuit 106 illustratively includes an FET driver IC, such as, for example, a Microchip Technology Inc., TC4426COA dual high-speed power MOSFET driver IC having INputA, GrouND, INputB, notOUTputB, VDD, and notOUTputA terminals, pins 2-7, respectively. The Q output terminal of oscillator circuit 104 is coupled to the INA terminal of driver circuit 106. The GND terminal of driver circuit 106 is coupled to ground. The notQ output terminal of oscillator circuit 104 is coupled to the INB terminal of driver circuit 106. The VDD terminal of driver circuit 106 is coupled to 5 VDC, and through a 100 nF capacitor to ground. The cathode of a 6.7 V Zener diode is coupled to the VDD terminal and its anode is coupled to ground.
The notOUTA and notOUTB terminals of driver circuit 106 are coupled to the gate electrodes of respective MOSFET switches 108-1 and 108-2. Switches 108-1 and 108-2 illustratively are International Rectifier IRLU3410 power MOSFETs. The gates of switches 108-1, 108-2 are coupled to the cathodes of respective 7.5 V Zener diodes, illustratively ON Semiconductor 1SMA5922BT3 Zener diodes, whose anodes are coupled to ground. The source terminals of both switches 108-1, 108-2 are coupled to ground, and their drain terminals are coupled to the opposite end terminals 110-1-1-1 and 110-1-1-2 of primary 110-1. The drains of switches 108-1, 108-2 are also coupled to the cathodes of respective 68 V Zener diodes, illustratively ON Semiconductor 1SMA5945 Zener diodes, whose anodes are coupled to ground. A series 33Ω, 0.5 W resistor and 4.7 nF capacitor are coupled across terminals 110-1-1-1 and 110-1-1-2 of primary 110-1. Voltage is supplied to a center tap 110-1-CT of primary 110-1.
Referring now particularly to
Regulated voltage supply 114 illustratively includes an ON Semiconductor LP2951ACDM low power, low dropout voltage regulator IC having OUTput, SeNSE, ShutDown, GrouND, notERRoroutput, Vo TAP, FeedBack and INput terminals, pins 1-8, respectively. The OUT and SNSE terminals are coupled together and form the 5 VDC supply. A 10 nF capacitor is coupled across the combined OUT and SNSE terminals, on the one hand, and the FB and TAP terminals, on the other. The parallel combination of a varistor such as, for example, an AVX VC120626D580DP, and a 1 μF, 25 V capacitor is coupled across the IN terminal and ground, and 5 Vin is coupled to the IN terminal.
A VCT voltage supply 123 with a maximum magnitude of, for example, 24 VDC, is coupled to the center tap 110-1-CT of primary 110-1. VCT power supply 123 may be, for example, a power supply of the type illustrated and described in one of the above-identified U.S. Pat. Nos. 5,978,244; 6,144,570; 6,423,142; or 6,562,137. Two parallel 22 μF, 35 V capacitors are coupled across the center tap 110-1-CT of primary 110-1 and ground. Gun 102 is also supplied with coating material from any suitable source 125, and additionally, may be supplied with compressed gas or mixture of gases (for example, compressed air) to aid in atomization from a suitable source 129.
Referring now particularly to
Referring now particularly to
The low voltage connection to the circuits mounted on PC board 119 is made through a low voltage contact plug 146 which is mounted on PC board 119. Plug 146 includes five terminals 146-1-146-5 providing the 5 Vin, VCT, IFB, LED and GND terminals.
A power supply fault condition indicates that high voltage cannot be delivered to electrode 130, for example, because the power supply 123 has detected a malfunction of its internal circuit, a malfunction of the conductor 150 coupling power supply 123 to VCT terminal 146-2, or a malfunction of gun 102 circuitry. The malfunction may be, for example, a temporary condition caused by the operator or the application. A power supply fault condition may also indicate that high voltage cannot be delivered to the electrode 130, for example, because the power supply 123 has determined that the maximum power capability of the gun 102 circuitry,
The system makes use of integrated LED indicators 118-1-118-6 and membrane switch 118-7 to indicate to the gun 102 operator that a fault has occurred and that high voltage cannot be supplied. The system also provides the gun 102 operator with the capability to reset the power supply 123 from the gun 102 once such a fault has cleared.
A signal conductor coupled to LED terminal 146-4 and a return conductor coupled to GrouND terminal 146-5 are connected to power supply control board 118. Zener diodes 118-8, 118-9 and 118-10 of increasing voltage ratings 2.7V, 5.1V and 7.5 V, respectively, and current limiting resistors of 750Ω resistance, 499Ω resistance and 249Ω resistance, respectively, are connected in series with the LEDs 118-1-2, 118-3-4, and 118-5-6, respectively. Each LED 118-1-6 is illuminated when the input signal voltage exceeds the corresponding Zener diode rating of 2.7V, 5.1V or 7.5 V, respectively. The total current consumed by the power supply control board 118 is proportional to the number of LEDs 118-1-6 that are illuminated. A resistor 118-11 is supplied in series from the input signal at LED terminal 146-4 through the switch 118-7 to circuit GrouND. Switch 118-7 activation causes an increase in total circuit current detected by the power supply 123. The illustrated power supply control board 118 accommodates three preset voltage levels at VCT terminal 146-2, which correspond to three preset output voltage levels at electrode 130. The desired level is selected by the operator by depressing membrane switch 118-7 once for each increase in the desired output voltage. If switch 118-7 is depressed after LEDs 118-5-6 are energized, the power supply 123 cycles back to the lowest preset voltage level, illuminating only LEDs 118-1 and 118-2. The current to power supply control board 118 is monitored by the power supply 123 as confirmation of the selected preset level.
Power supply 123 includes a circuit for detecting the total current. With reference to
A low value, for example, 100Ω, resistor 118-11 is in series with pushbutton switch 118-7. When switch 118-7 is momentarily closed, LED terminal 146-4 is coupled through resistor 118-11 to circuit GrouND terminal 146-5. The current source transistor 218 supplies constant output current commensurate with the commanded voltage level. Therefore, when current flows through switch 118-7 and resistor 118-11, the voltage at LED terminal 146-4 is reduced. The voltage reduction is interpreted by μP 200 as a pushbutton switch 118-7 depression.
The resistor values of 750Ω, 499Ω and 249Ω, respectively, associated with each LED color pair 118-1-2, 118-3-4, 118-5-6, respectively, decrease in value from green (118-1-2) through yellow (118-3-4) to red (118-5-6), respectively, and serve to limit current to below device maximum specifications. Each LED bank 118-1-2, 118-3-4, 118-5-6 is illuminated at the desired source transistor 218 output current and voltage at LED terminal 146-4. As the source signal at LED terminal 146-4 is commanded to increase by depression of switch 118-7, raising the voltage at LED terminal 146-4 until the next Zener diode 118-9 or 118-10 in sequence begins to conduct. This places another pair of LEDs 118-3-4 or 118-5-6 and their associated 499Ω or 249Ω resistors, respectively, in parallel with the LEDs 118-1-2 and their associated 750Ω resistors. The current increases through each pair of LEDs 118-1-2, 118-3-4, 118-5-6 given that the source signal is of sufficient magnitude to bias the 2.7 V Zener diode 118-8, the 5.1 V Zener diode 118-9 and the 7.5 V Zener diode 118-10 into conduction. Therefore, the developed output voltage at LED terminal 146-4 increases as the source signal current increases thereby illuminating each LED color bank 118-1-2, 118-3-4, 118-5-6 in succession.
In the event the μP 200 detects a fault condition, it removes the voltage at VCT terminal 146-2. It also pulses the base of transistor 218 with sufficient drive signal to illuminate all of LEDs 118-1-6, so that LEDs 118-1-6 flash, advising the operator of the fault condition. The operator depresses the membrane pushbutton switch 118-7 for at least two seconds to turn off the flashing LEDs 118-1-6. The operator may then depress switch 118-7 for two seconds to reinitialize the supply of voltage at the lowest preset level to VCT terminal 146-2, illuminating LEDs 118-1-2. If μP 200 does not detect a fault condition, operation of gun 102 proceeds. If μP 200 again detects a fault condition, it again removes the voltage at VCT terminal 146-2 and pulses the base of transistor 218 with sufficient drive signal to illuminate all of LEDs 118-1-6, so that LEDs 118-1-6 flash, advising the operator that the fault condition persists. The operator may then disable LEDs 118-1-6 and investigate the cause of the fault.
