US2764125A

US2764125A - Electrostatic atomizing and coating apparatus

Info

Publication number: US2764125A
Application number: US271625A
Authority: US
Inventors: James W Juvinall
Original assignee: Ransburg Corp
Current assignee: Ransburg Corp
Priority date: 1952-02-14
Filing date: 1952-02-14
Publication date: 1956-09-25
Anticipated expiration: 1973-09-25

Description

W 19% J. W. JUVINALL 2,764,125

ELECTROSTATIC ATOMIZING AND COATING APPARATUS Filed Feb. 14-, ,1952

4 Sheets-Sheet 1,

IN V EN TOR.

JAMES W. J UVINALL BY hi5 11:956 J. W; JuvmALL 21,764,125

ELECTROSTATIC ATOMIZING AND COATING APPARATUS Filed Feb. 14, 1952 4 Shets-Sheet 2 I IIIIII. K L" IN V EN TOR.

| JAMES W. JUVINALL ,d/farney 1Q 1956 J. w. JUVHNALL ,7

ELECTROSTATIC ATOMIZING AND COATING APPARATUS 4 Sheets-Sheet 3 Filed Feb. 14, 1952 INVENTOR.

JUVINALL JAMES W.

Afforney I a znia S AN 25, 1956 J. W. JUVENALL 2,,764 125 4 Sheets-Sheet 4 V INVENTOR.

JAMES w. JUV/NALL. BY

ATTORNEY United States Patent ELECTROSTATIC ATOMIZING AND COATING APPARATUS James W. Juvinall, Indianapolis,

Ind., assignor to Ransburg Electro-Coating Corp.,

This invention relates to apparatus for spray-coating articles. More particularly it is directed to the adjustment of one or more atomizing heads of such apparatus for obtaining desired coating material distribution on articles to be coated and to the adjustment of the atomizers of coating apparatus when an electric field is established over the surface of the article to aid in the precipitation of coating material.

In the coating art the problem of obtaining a desired coating material distribution over the surface of an article to be coated has been a major one which can only be solved after the atomizers of the apparatus are readily adjustable to all positions with respect to the surface being coated and are easily fixed in any position to which they can be adjusted. This is particularly true where the surface being coated is extended and the number of atomizers is large.

More recently it has been found desirable to utilize electrostatic fields in cooperation with coating apparatus wherever possible because of high coating eificiences obtained by such apparatus. However, the problem of coatting material distribution and the adjustment of atomizers also exists in this case.

That form of such coating apparatus which yields the highest coating etficiences includes one or more discharge devices which are maintained at high voltage. Such device may comprise a discharge member such as a bell having the form generally of a hollow cone and which may be mounted in series for rotation about the principal axis of the cone. Suitable apparatus may be provided for mounting the bell opposite an object having a surface to be coated. Simultaneously with the rotation of the bell, coating material may be injected through an orifice at the apex of the bell, the coating material flows in the form of a film over the inner surface of the bell to its outer periphery from where it is atomized in the form of a spray. The electrostatic field that exists between the discharge member and the surface to be coated effects the deposition of the spray on the article. When a sta tionary flat sheet of material to be coated is disposed opposite to such bell, a spray pattern is precipitated thereon which is in the form of an annulus or doughnut devoid of coating material at its center. When the flat sheet is moved with respect to the atomizing head, the pattern of this form produces on the surface a coated area of non-uniform film thickness whereby there is a thick band of coating material at either edge and a relatively thin band of coating material in the center.

Due to the non-uniform material distribution obtained from such single bell type atomizers, their utilization in some instance have been restricted notwithstanding the high coating efficiencies which can be obtained through the use of apparatus incorporating such atomizers.

To supplement the deficiencies of such single heads, additional heads are used in overlapping relationship to each other and in this way large areas can be uniformly coated. Such combining of many bell-type atomizers requires free movement of such atomizers relative to the 2 surface being coated and accurate control over the positions of such atomizers when theyare in final or combined position.

Accordingly it is the principal object of this invention to provide novel coating apparatus for coating surfaces of extended area more uniformly and with high efficiency.

Another object of this invention is to provide novel electrostatic coating apparatus adapted to form a coating of desired distribution.

Still another object of this invention is to provide in an electrostatic coating apparatus using a plurality of atomizers a supporting mechanism providing ready adju'stment of those atomizers With respect to each other and With respect to a surface to be coated and permitting the sprays from the plurality of atomizers to be combined to obtain a coating of desired distribution on the surface to be coated.

A further object of the present invention is to provide a novel, multiple atomizer coating apparatus which is simply and conveniently adjusted to permit coating article surfaces which vary in dimension and shape from run to run and also which is of rigid construction and is adapted to remain in a predetermined adjusted condition from run to run.

Still a further object of this invention is to provide, in an electrostatic coating apparatus using a plurality of rotating atomizing heads, electrically insulated driving connections adapted to permit the driving of said heads from a single electrically grounded motor.

A still further object of this invention is to provide electrostatic coating apparatus in which the electrostatic atomizing head or heads are electrically insulated from ground and to which "electrically conducting coating materials may be fed without electrically grounding the atomizing head orheads.

A still further object of this invention is to provide novel means for supporting a plurality of multiple head atomizing units which permit coincident adjustment of the atomizing units and also separate adjustment of each such unit relative to the surface being coated.

In accordance with one feature of this invention there is provided an atomizing unit comprising a support, a plurality of discharge devices rotatably mounted on the support, and driving mechanism connected to each of the discharge devices for rotating such devices.

In accordance with another feature of this invention there is provided an atomizing apparatus comprising a stand, a support mounted on the stand, one or more rotating atomizing heads mounted on the support and ad justable connections between the stand and support for providing adjustment of the atomizing heads.

In accordance with another feature of this invention, there is provided an apparatus for coating a surface of an article comprising a stand adjacent the article to be coated, one or more atomizing units each of which includes one or more discharge devices, and adjustable connections between the units and the stand to permit uniform adjustment of the discharge device or devices relative to the surface being coated.

For a better understanding of the invention, with other and further objects thereof, reference is made to the following description, taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

In the accompanying drawings:

Figure l is an isometric view of a multiple head electrostatic coating apparatus illustrating one embodiment of my invention.

Figure 2 is an enlarged isometric view partly in section of a portion of the apparatus shown in Figure 1 illustrating the adjusting mechanism for an atomizing unit.

together Figure 3 is a cross-sectional view taken on line 3-3 of Figure 4 with certain parts omitted.

Figure 4 is a cross-section taken on line 4-4 of Figure l with certain parts omitted.

Figure 5 is a top plan view of a multiple head electrostatic coating apparatus illustrating another embodiment of my invention.

Figure 6 is a side elevation view of the apparatus illustrated in Figure 5.

Figure 7 is an end view of the apparatus illustrated in Figure 5.

While one form of atomizing unit and two forms of apparatus for adjustably supporting one or more atomizing units are illustrated in the drawings and will be described hereafter as providing a coating of desired distribution on a surface, it will be understood that these are representative embodiments only. It will also be understood that forms of atomizing units other than the particular atomizing unit shown may be utilized, that the atomizing unit may comprise more or less than the three 9 atomizing heads shown, and that forms of adjustable supporting apparatus other than the particular adjustable supporting apparatus shown may be utilized; and it is to be understood that no limitations are to be implied from such spcific description as is now provided. 1

Referring to the drawings, particularly to Figure 1 thereof, there is provided in accordance with one embodiment of my invention a plurality of articles 10 supported on supports 12 for movement over a predetermined path past coating apparatus by means of a conveyor 14.

The coating apparatus comprises a plurality of atomizing units, 16, 17 and 18. Each atomizing unit comprises three

atomizers

20, 21 and 22, which include atomizing heads or

discharge devices

24, 25 and 26, respectively, in the form of rotatable bells. As illustrated, the

bells

24 and 26 may be of a smaller size than the bells 25. The size of the bells may be selected so that when they are properly adjusted relative to each other and the articles being coated a coating pattern will be provided for obtaining a coating of uniform thickness on the articles being coated. The bell portions of these atomizers is being claimed in the copending U. S. application Serial No. 229,247, filed May 24, 1951.

Atomizers

20, 21 and 22 are connected together structurally by means of electrically

conductive shaft housings

28 and 30. For supporting the atomizers and housings of each atomizing unit and insulating them from ground,

shaft housings

32 and 34 at least partially of electrically insulating material, are connected to the

atomizers

20 and 22, respectively, and supports or

connectors

36 and 38, respectively. Thus, there is provided an electrically insulated multiple head atomizing unit.

For supplying coating material such as paint, enamel, and the like to the atomizing heads of each unit 16, 17 and 18, there is provided a pump 40 which conveniently may be insulated from ground and which may be connected to each head by a separate pipe. For the sake of simplicity only

pipes

42, 43, and 44 connecting the

heads

20, 21 and 22, respectively of atomizing unit 18 with pump 40 are shown. The pump 40 is supplied with coating material from container 46 by means of pipes 48, 49 and 50. If desired, the container 46 may be insulated from ground by means of legs 52 made of electrically insulating material. The container 46 may be provided with an air driven agitator 54 for mixing the coating material. The agitator may be energized by means of air from hose 56. Both container 46 and pump unit 40 may conveniently be supported on platform 58, which bridges the conveyor 14.

The bells of each of the atomizing units 16, 17 and 18 are maintained at an electrical potential, for example 90,000 volts, by means of

conductors

60, 61 and 62, which are connected to one terminal of high voltage pack 64 while the other terminal of the high voltage pack as well as the articles 10, through the conveyor 14, are electrically grounded as indicated. Thus a high voltage electrostatic field is established between the bells of each of the atomizing units 16, 17 and 18 and the articles 10.

For connecting the atomizing units 16, 17 and 18 to permit their adjustment in a plane parallel to the path of article movement as well as normal thereto, there are provided frames 66 and 67 which bridge the conveyor 14 at spaced locations along its path of movement. Each frame comprises a pair of

standards

68 and 69 mounted on bases 70 and 71, respectively, and a tube slidably connected to the

standards

68 and 69 by

brackets

74 and 75, respectively.

Referring to Figure 2, the bracket 75 comprises tubular section '76 slidably mounted on the standard 69 and socket 78 for receiving one end of the tube 72. In order to adjustably move bracket 75 and the tube 72 connected thereto along the standard 69, the upper portion of the standard 69 is threaded as shown at 80. Adjustable member or nut 82 is threadedly mounted on the standard 69 below the bracket 75. A stabilizing nut 34 is provided above sleeve 76 and threaded on threads 80. By withdrawing nut 84 and rotating the adjustable nut 82 the bracket may be adjusted upwardly or downwardly along the standard 69 in any desired position. This results in adjusting the atomizing units 17, 18, and 19 toward and away from the articles 10 on the conveyor. By rotating the stabilizing nut 84 into engagement with the bracket 75, it functions to hold the bracket 75 rigid relative to the standard 69. The adjustable and stabilizing

nuts

82 and 84 may be provided with

shields

86 and 88, respectively, to maintain the threaded portion of the standard 69 in a clean condition.

The supports 36 and 38 of each atomizing unit are connected to the tubes 72 of the frames 66 and 67 and permit adjustment of each atomizing unit in a plane parallel to the path of movement of the articles 10. Referring to Figure 2, the support or connector 36 for adjustably supporting atomizing unit 17 comprises clamp 90 and angle member 92. The clamp 90 is mounted on the tube 72 of frame 66 for adjustable movement along the tube 72 and is adapted to be fixed in any desired position by the screws 94. The angle member 92 comprises

sections

96 and 97 which are at an angle to each other. Section 96 is provided with pin 98, and section 97 is provided with socket 102. The angle member 92 is connected to the clamp 90 by screw 1614 which extends through arcuate opening 106 in the lower portion of the clamp. This connection permits pivoting the angle member 92 about the axis of the pin 98 for any desired adjustment and also permits fixing the angle member 92 relative to the clamp by tightening screw 104 after the proper adjustments have been made. The socket 102 supports the housing 32 of the atomizing unit 17, which is fixed in the socket by screw 108. A motor is afl'lxed to the section 96 in a suitable manner and functions to drive the bells of the atomizing unit 17 in a manner to be described in greater detail hereafter. The motor 110 is connected to a source of power (not shown) by means of conductor 112. The connector 36 and the motor 110 are enclosed by a housing 114 which has smooth contours and preferably is of electrically insulating material. The housing 114 is supported on the motor 110 and the socket 102 by means of mounting sleeves 116 and 118, respectively.

The adjustable connector 38 comprises clamp 120 and swivel member 122, both of which are formed to present a smooth uniform contour to reduce to a minimum any field reducing effect these parts may have on the atomizing field at the discharge devices and to facilitate in keeping these parts clean. Clamp 120 is provided at its lower end with a tubular section 124 in the outer peripheral wall of which there is formed annular groove 126. This clamp is mounted on the tube 72 of frame 67 for adjustable movement along the tube 72 and is adapted to be fixed in any desired position by the screws 128. The swivel member 122 is provided with sockets and 132 formed perpendicular to each other and is swivelly mounted on the clamp by screw 134, which connects sockets and tubular section 124 and is adapted to move in the groove 126. After the swivel member 122 is adjusted as desired, it may be fixed in this position by tightening the screw 134. The socket 132 slidably supports the member 34 of the atomizing unit 17. Screw 136 is provided on the end of the member 34 to prevent it from slipping out of the socket 132 during adjustment. After adjustment of the atomiz'ing unit 17 relative to the swivel member 122 is accomplished, the member 34 is fixed in position relative to the socket 132 by means of screw 13?).

Referring again to Figure l, the electrical power for energizing the high voltage pack or, the bell motors 110, the pump unit as, and the conveyor 14 is "supplied from a source (not shown) by means of conductor 140 which is connected to a control panel 142 through master switch 1 M and conductor 146. The control panel distributes the electrical power to the high voltage pack 64 by means of conductor 148. The connection of the control panel t 142 to the bell motors 1110, pump unit 40, and to the conveyor 1 tare not shown. The switches 150, 151, i152 and 153 on the control panel function to energize and deenergize the high voltage pack, the bell motors, the pump unit, and the conveyor, respectively. Also the control panel may be provided with a control knob 154 for varying the voltage of the discharge devices of each of the atomizing units 1 17 and 18.

Referring to Figure 3 of the drawings, each of the atomizers 12d, and 22 of each atolnizing unit is sub stantially identical in construction. Therefore, atomizer 21 will be described as typical. The atomizer includes a gear housing 16d, a seal housing 161 bolted thereto by means of a suitable bolt 162, a rear end cover 163, and a front end cover 16 1. to present a smooth, uniform contour to reduce to a minimum any concentration of electrostatic field on these parts. Within the gear housing there are provided bearings 165 and to; for rotatably supporting the drive shaft 167 upon which the bell -24- may be suitably mounted onthe front end thereof. I

Shaft 167 is provided with a passage 169 for supplying paint or other coating material to the interior surface or the bell 24. For coupling the passage 169 to one of the pipes, such, for example as the pipe 42, there is provided a coupling member 170 which may be threaded or otherwise attached to the seal housing 161. For sealing the shaft so that coating material will not leak from the space between coupling 1'70 and the end ofshaft 167, there are provided a plurality of chevron seals 171. In this manner the coating material may be piped into a rotating shaft without danger of leak-age. I

For driving the shaft 167 there is fixed thereto a helical gear 172 which is adapted to mesh with apinion gear 173 fixed on a drive shaft 174. Shaft 17 i is rotatably supported in a manner that will be described subsequently.

For permitting electrical connection of the assembly to the voltage pack 64 there is provided a plug receiving aperture 175 and a set screw 176 for engaging the plug to retain it within the aperture. Since all of the atomizers on one atomizing unit are connected electrically -by housing 28 and 311 only a single electrical connection to a single atomizer is necessary. 1

Referring to Figure 4 of the drawings, it will be noted the shaft 174, mounted in bearings 177, may be driven from the motor 110 Within the housing 114 by means of a coupling 178 connected to the motor and to a shaft 179 made of insulating material and extending from the motor coupling to the coupling 180 within housing 160. Shaft 179 may be rotatably mounted by means of bearing 181 which is in turn mounted within the insulating housing 32. Thus the motor 110 may drive shaft 174 through shaft 179. Shaft 174 is in turn coupled to shaft 182 by means of a flexible coupling 183. The electrically con-

Covers

163 and 164 are formed 6 ducting shaft housing 28 in the form of a metallic cylinder extends from the atomizer 20 to the atomizer 21.

Shaft 182 extends along the axis of the housing 28 from the coupling 183 to atomizer 21 whereby there is a driving connection between atomizers 20 and 21. Each of the atomizers is formed to provide sockets 184 for receiving the ends of

shaft housings

28, 30, 32 and 34 whereby the atomizers may be supported by the housings.

Atomizer 21 comprises substantially the same structure as atomizer 21), shaft 182 having attached thereto a helical gear 185 and being supported by means of bearings 186. Gear 1 85 corresponds to gear 173 of atomizer 2'0. Shaft 182 extends through the assembly to the flexible coupling 187 which may be attached to another drive shaft 188. Shaft 188 extends through the electrically conductive housing 30 to the atomizer 22 and terminates therein. The shaft 188 is provided with helical gear 189 which corresponds to

gears

173 and 185, for driving bell 26. The atomizer 22 is similar to the atomizers 20 and 21 except that it is connected to the swivel'ed 'end member 122 by means of the insulating housing 34. Housing 34 terminates in a metallic 'end shaft 190 which may be arranged to slide inwardly and outwardly with respect to member 122 as previously explained whereby the entire assembly of

atomizers

20, 21 and 22 may be adjusted in a horizontal plane.

In operation the tubes 72 are adjusted so that the

atomizers

20, 21 and 22 of each atomizing unit are spaced the proper distance from the surface of the articles 10 on the conveyor 14. Then the

connectors

36 and 38 of each atomizing unit connected to the horizontal tubular members 72 are adjustably spaced along these tubes and are adjustably pivoted about their axes so that the bells are properly positioned relative to each other so that the patterns from all the bells are interlaced to obtain a uniform coating on the articles to be coated. Thereafter, the voltage pack '64, bell motors 110, and the pump unit "40 are energized by actuating the switches 150, 151 and 152, respectively. With the coating apparatus in operation, the conveyor 14 is energized by actuating switch 153 for moving articles past the bells of the coating apparatus for being coated thereby.

In the embodiment of the invention just described, coatings of commercially satisfactory quality have been obtained on sheet metal siding sections 68 inches long when the following specifications were followed; the sheets were arranged on the conveyor moving 1.5 feet per minute so that their 68 inch dimensions were transverse to their direction of travel; each atomiz-ing unit was provided with two outside bells 4 inches in diameter and an intermediate hell 6 inches in diameter; the three atomizing units were adjusted into positions so that the discharge edges of each bell were coplanar and at a distance of 13 inches from the sheets, the bells on each atomizing unit were spaced so that the axes of adjacent bells were 18 inches apart, the axes of the smaller bells of each atomizing unit were offset 3 /2 inches from the axis of the larger bell in opposite directions transversely of the path of sheet travel and the axes of the larger bells of adjacent atomizing units were spaced 22 /5. inches from each other and the axis of the larger bell of the central atomizing unit was spaced 34 inches from the opposite sheet edges arranged parallel to the path of sheet movement; a D. C. potential diiference having an average value of 90,000 volts was maintained between the bells and the sheets; the heads were rotated at approximately 900 R. P. M.; and a modified urea formaldehyde olive drab enamel (20 sec. viscosity on a No. 2 Zahn cup at 75 degrees F.) was supplied to each of the smaller bells at a rate .of 60 cc. per minute and to the larger bell at the rate of 90 cc. per minute.

Another embodiment of my invention is illustrated in Figures 5, 6 and 7 of the drawings where there is shown an electrostatic coating apparatus comprising a plurality of atomizers 20 1, 202, 203, 204, 205 and 206 including discharge devices in the form of rotatable bells. As illustrated,

atomizers

201, 203, 204 and 206 may have bells of smaller size than

atomizers

202 and 205. The sizes of the bells may be selected to provide a coating pattern such that a coating of uniform thickness may be produced on an article to be coated. The atomizers and bells just referred to are similar in construction to the atomizers and bells of the apparatus described in connection with Figures 1-4.

Atomizers

201, 202, 203 are connected together structurally and supported by means of electrically

conductive shaft housings

210 and 211.

Atomizers

204, 205 and 206 are structurally connected together by similar housings. A source of high voltage may be connected to the structure of oneor more of the atomizers and to the object to be coated. Thus, a high voltage electrostatic field may be created between the bells and the articles 212 to be coated for precipitating atomized coating material from the periphery of the bells to the surfaces of the articles to be coated. For supporting the atomizers and housings and insulating them from ground, the

shaft housings

215 and 216 of insulating material are connected to the

atomizers

201 and 203, respectively, housing 215 extending into a socket within a swivel support or connector 218 and housing 216 extending into a socket within a swivel support or connector 219. The

connectors

218 and 219 may be of similar construction to

connectors

36 and 38, respectively, described above in connection with Figures 1 and 2. Thus there is provided an electrically insulated, multiple head atomizing unit.

For movably or tiltably supporting each atomizing unit so that it may be moved in a vertical plane and adjusted at various angles with respect to the horizontal, there are provided a pair of

columns

220 and 221 mounted on

bases

223 and 224. Each atomizing unit is connected to these columns by the

swivel clamping connectors

218 and 219. By moving these swiveled clamping

connectors

218 and 219 upwardly or downwardly on

columns

220 and 221 the angle to the horizontal of the atomizing units may be adjusted in whatever fashion may be necessary to obtain a coating of uniform thickness on the articles 212.

For supplying paint to the

atomizers

201, 202 and 203 there is provided a pump 228 which may be connected to

atomizers

201, 202 and 203 by means of

pipes

229, 230 and 231, respectively. lump 228 may be connected to a source of coating material (not shown) such as paint, enamel or the like by means of a pipe 232. The

atomizers

204, 205, and 206 may likewise be connected to the pump 228, as will be obvious to those skilled in the art.

In utilizing the apparatus illustrated in Figures 5, 6 and 7 there may be provided a conveyor 233 adapted movably to support a plurality of the articles 212, such as the cylinders shown, adjacent the electrostatic apparatus described above. v The most desirable positions of the

atomizers

201, 202, 203, 204, 205 and 206 may be determined by moving the

swivel connectors

218 and 219 up wardly or downwardly until they are in such a position that a coating of desired distribution is applied to the surfaces of the articles. Suitable means may be provided for slowly rotating the articles 212 as they move past the electrostatic coating apparatus such as by rack bar 234 engageable by pulley 235 on the article supports.

In operation, after high voltage is applied to the atomizers the motors supported on connectors 218 may be energized thereby to rotate the bells of atomizers 3201-206. Upon the energization of the pump 228 coating material flows from the

pipes

229, 230 and 231 to feed coating material to the rotating bells of each atomizing unit. As the bells rotate the coating material spreads over the inner surface thereof and is atomized from the front edge and electrostatically precipitated on the surface to be coated.

It will be readily understood from the foregoing description that there are provided by this invention structures for supporting a plurality of atomizing bell units in relatively fixed relation to one another, and which also permit adjustment in a horizontal plane, a vertical plane and toward and away from the surfaces to be coated. Thus, these structures are adapted readily to combine the patterns from a plurality of atomizing units into an integrated single pattern which has the desirable distribution of thickness and area desired. It will also be understood that apparatus is provided in accordance with this invention for driving a plurality of atomizing bells from a single motor. Furthermore, these adjustment and driving features permit insulation from ground, even though high voltages are used in the coating process.

While there has been described what is at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

I claim:

1. An atomizing unit comprising a plurality of atomizers each of which includes a casing, an atomizing head rotatably mounted on said casing and mechanism within said casing for driving said head; a supporting structure for said atomizers comprising electrically conductive shaft housings joined to and between the casings of said atomizers for supporting and electrically interconnecting them, and end shaft housings at least partially of electrically insulating material connected to the outer atomizers for providing electrical isolation of said atomizers; and drive mechanism comprising interconnected shafts within said conductive housings and connecting said driving mechanisms within said atomizers, an end shaft at least partially of electrically insulating material within one of said end housings and drivingly connected to one of said conductive shafts, and a motor connected to said end shaft.

2. An atomizing unit comprising a plurality of atomizers, each of which includes a casing, an atomizing head rotatably mounted on said casing, a rotatable shaft mounted within said casing and connected to said head for rotating it, and gear mechanism for driving said shaft; a supporting structure for said atomizers comprising electrically conductive shaft housings joined to and between the casings of said atomizers for supporting and electrically interconnecting them, and end shaft housings at least partially of electrically insulating material connected to the outer atomizers for providing electrical isolation of said atomizers; and drive mechanism comprising interconnected electrically conductive shafts within said conductive housings and connecting the gear mechanisms within said atomizers, an end shaft of electrically insulating material within one of said end housings and drivingly connected to one of said conductive shafts, and a motor connected to said end shaft.

3. An atomizing apparatus comprising a frame including a pair of spaced apart cross members; a plurality of atomizing units each of said units including a support, an atomizing head rotatably mounted on said support, and a shaft rotatably mounted on said support and operatively connected to drive said atomizing head; a motor connected to each shaft for driving said shaft; and a pair of adjustable connectors for connecting opposite ends of each of said supports to said cross members, one connector associated with each atomizing unit having a motor support member for the motor associated therewith, each motor and its corresponding support member being arranged in staggered relation along said cross members.

4. An electrostatic apparatus comprising a pair of spaced parallel columns; an atomizing unit including a support comprising electrically insulating portions connected by an electrically conductive portion, and a plurality of spaced atomizers having rotating heads mounted on said conductive portion; adjustable means connecting said support to said columns to permit angular adjustment of said support and said heads as a unit; and head driving greens 9 means supportingly integrated with said supper: and drivingly connected to said heads. j

5. An electrostatic apparatus comprising a pair of spaced parallel columns; an atomizing unit including a housing extending between said columns and comprisin of electrically insulating end portions connected by an electrically conductive portion, a plurality of spaced atotiiizers having rotating heads mounted onsai'd "conductiv'e portion, and a shaft rotatably mounted 'vv'ithin said housing and connected to said head's'for rotating them; means for tiltably supporting one end of said unit comprising a socket for receiving one end df said housing, and adjustable means for pivotally connecting said socket to one of said columns; and means for tiltably supjidrting the other end of said unit comprising a motor, a suppdrt member therefor, said support member including a socket for receiving one end of said shaft for ccn'rieetion to said motor and the other end of said stun musin respectively, and means for pivotally connecting said suppdrt member to said other column.

6. An electrostatic appaartus comprising v a pair of spaced vertical columns; an atomizing unit including a housing extending between said columns and comprising of electrically insulating end portionsconnected by an electrically conductive portion, a plurality of spaced atomizers having rotating heads mounted on said eonductive portion, and a shaft rotatably mounted within said housing and connected to said heads for rotating them; means for tiltably suppoiti'ng one end of said unit comprising a socket for receiving one end of said housing, a swivel connected thereto and a clamp connecting said swivel to one of said columns; and means for tiltably supporting the other end bf said tiriit comprising a eter, a support member therefor, said suppd'ft rhrhbei" including a socket for receiving one end of said shaft for connection to said motor and the other end of said shaft housing respectively, a swivel connected to said supporting member and a clamp for connecting said swivel'to said other column.

7. An electrostatic apparatus comprising a frame including a member; an atomizing unit including a support and a plurality of spaced atomizers each having discharge portions mounted on said support; a connector secured to the atomizing unit support, and adjusting means for securing the connector to said frame member in any one of a plurality of positions to permit angular adjustment of said discharge portions as a unit in a predetermined plane.

8. The invention set forth in claim 7 with the addition that said frame also includes a column, said frame member includes a tubular portion whereby it is slidably mounted on said column and an adjustable member movably mounted on said column and being in engagement with said frame member for adjusting said discharge portions relative to said predetermined plane.

9. Apparatus for electrostatically coating an article comprising a frame including a column and a member slidably mounted on said column, said frame being adjacent the article to be coated; a plurality of atomizing units, each of said units comprising a support and an atomizer having a discharge portion mounted on said support; a separate connector for connecting each of said atomizing unit supports to said slidable member for holding said atomizing units in spaced relation to each other; and an adjustable member movably mounted on said column for moving said slidable member to adjust said discharge portions relative to the surface of the article to be coated.

10. An atomizer comprising a housing having aligned sockets on opposite sides for reception of tubular members by which the atomizer may be supportingly connected to adjacent similar atomizers, a shaft section rotatably mounted in said housing and having end portions projecting into said sockets, a head spindle rotatably supported in said housing, gearing operatively interconnecting said spindle and said shaft section, and an atomizing head connected to said spindle for being driven thereby.

ll. An atomizing unit comprising a plurality of ateniizers, each at which comprises a supporting stare titre, a shaft section rotatably mounted on said structure, a head spindle rotatably mounted (in said structure, gearing o'p'eratively interconnecting said spindle and said shaft section, and an atomizing head connected to said spindle for being driven thereby; means for supportingly interconnecting said atomizers with their respective shaft section in alignment; coupling means drivingly interconfleeting the shaft sections of adjacent atomizers, and motor means connected to one of said shaft sections to rotate all of said interconnected shaft sections. 1 12. An a'tomizing unit as set forth in claim ll with the tion that said means for supportingly interconnecting adjacent atomizers comprises a tubular member and provisions on the supporting structures telescopically associated with the ends of said members, said coupling means comprising a shaft disposed in said tubular member.

13, Atemtzing apparatus comprising a plurality of atomizers, each ha'ving a housing with oppositely disposed aligned sdckets for reception of tubular members by which the at'oiuiiers may be supporting'ly connected to adjacent similar atomizers, a shaft section rotatably mounted in said housing, end portions of said shaft section projecting into said sockets, a head spindle rotatably supported in said housing, gearing operatively interconnecting said spindle and said shaft section, and an atomizing head connected to said spindle for being driven thereby; means including electrically conductive tubular members received in said sockets for supportingly and electrically inte rc infecting said atbmizers With their respective shaft sections in alignment; coupling means drivingly interconnecting the shaft sections of adjacent atomizers; spaced supports; and additional tubular members of insulating material received in the sockets of the end atomizers and connected to said supports.

14. An atomizing apparatus comprising av plurality of atomizing units, each atomizing unit comprising a plurality of atomizers each having a housing with oppositely disposed aligned sockets for reception of tubular members by which the atomizers may be supportingly connected to adjacent similar atomizers, a shaft section rotatably mounted in said housing and having end portions projecting into said sockets, a head spindle rotatably supported in said housing and offset from said shaft section, gearing operatively connecting said head spindle and said shaft section, and an atomizing head secured to one end of said spindle for being driven thereby, said shaft having an axial passage extending through it and communicating with the interior of the head at one end of the shaft, means for supplying liquid to be atomized to the opposite end of said passage, means including electrically conductive tubular members received in said sockets for supportably interconnecting said atomizers with their respective shaft sections in alignment, coupling means drivingly interconnecting the shaft sections of adjacent atomizers, an additional shaft section of insulating material connected to the shaft section of one of the end atomizers, and a motor connected to said additional shaft section; a pair of spaced parallel supports; a pair of connectors for connecting each of said atomizing units to said parallel supports, each of said connectors comprising a first portion slidable on its associated support and a second portion swiveled to said first portion on an axis perpendicular to said support and adapted to support the associated atomizing unit, the motor of said atomizing unit being supported on the second portion of one of said connectors; a pair of columns for supporting each of said parallel sup ports; means for slidably mounting said supports on said columns; and means including a nut threadedly mounted on each of said columns for adjusting said support relative to said columns.

15. An atomizing apparatus comprising a frame which includes a support member; an atomizing unit including a support, an atomizer having a rotatable head mounted on said atomizing unit support, and a shaft rotatably mounted on said support and connected to drive said rotatable head; a motor connected for driving said shaft; a connector rigidly connected to said atomizing unit support, means supportedly connecting said connector and support member, said means being adjustable to permit relative movement of the atomizing unit support and said support member, a housing of electrically insulating material for enclosing at least a portion of said connector and the motor supported thereby, and means for supporting said housing in spaced relation from said connector and said motor except at points of support.

16. Apparatus for electrostatically coating an article comprising a frame including a support member adjacent to the article to be coated, said frame support member having a threaded portion; an atomizing unit including an atomizer having a discharge portion; means for supporting said atomizing unit on said frame for holding said discharge portion in spaced relation from the article to be coated, said means including a member connected to said atomizing unit and slidably mounted on the frame support member; a nut threadably mounted on the threaded portion of the frame support member and having a shield for enclosing the exposed portion of said threaded portion, said nut being in engagement with said slidable member for adjusting the distance between said discharge portion and the surface of the article being coated.

17. The invention set forth in claim 16 With the addition of said nut engaging said slidable member on one side thereof and of a second nut threadedly mounted on said threaded portion for engaging said slidable member on the opposite side to said first nut for maintaining the slidable member and the atomizing unit connected thereto in a rigid adjusted condition.

18. An atomizing apparatus comprising an atomizing unit including an elongated tubular support and a plurality of atomizing heads rotatably mounted on said tubular support; a drive shaft extending through said tubular support; means connecting the drive shaft to each of said heads to rotate the same; a pair of spaced parallel columns; means on each end of said tubular support for connecting said tubular support at its ends to said columns for adjustment to any one of a plurality of positions; a motor connected to said shaft for rotating the same; means for maintaining each of said heads at a high electrical potential, and means insulating said columns from the electrical potential applied to said heads.

19. The atomizing apparatus of claim 18 including a conveyor for conveying a plurality of articles, said columns being positioned generally equidistant from the path of article movement and in which column-position the tubular support in any one of said adjustable positions lies in a plane generally parallel to, but spaced from, the path of article movement.

References Cited in the file of this patent UNITED STATES PATENTS 1,832,096 Chaffee et al. Nov. 17, 1931 2,070,972 L-indenbland Feb. 16, 1937 2,442,986 Ransburg June 8, 1948 I 2,559,225 Ransburg July 31, 1951 FOREIGN PATENTS 982,327 France June 8, 1951 OTHER REFERENCES No. 2 Electrostatic Process, Publication of Ransburg Electro-Coating Corp.