US2569852A - Machine for applying specular coatings - Google Patents

Description

Oct. 2, 1951 J. H. GREEN MACHINE FOR APPLYING SPECULAR COATINGS 6 Sheets-Sheet 1 Filed NOV. 27, 1948 INVENTOR.

W TVIZNEY.

Oct. 2, 1951 GREEN 2,569,852

MACHINE FOR APPLYING SPECULAR COATINGS Filed Nov. 27, 1948 6 Sheets-Sheet 2 Jim/Pm? F/mu Ear/Muir WITNE55E5 V v INVENTOR 159 7. H. GEE EN I BY? B 1,95 1 w W 1K7 154 ATTORNEY Oct. 2, 1951 J. H. GREEN MACHINE FOR APPLYING SPECULAR COATINGS 6 Sheets-Sheet 5 Filed Nov. 27, 1948 dram/wily U INVENTOR J b. G'FfE/V.

Yfl MW farm/wavy WITNESSES ATTQRNEY Oct. 2, 1951 J. H. GREEN MACHINE FOR APPLYING SPECULAR COATINGS 6 Sheets-Sheet 4 Filed NOV. 27, 1948 INVENTOR J: H G'FEE/V 5 WITNESSES:

ATTORNEY JOWK m-4, @169; M

Oct. 2, 1951 J. H. GREEN v MACHINE FOR APPLYING SPECULAR COATINGS 6 Sheets-Sheet 5 Filed NOV. 2'7, 1948 ATTORN EY J? A. GE'EEAL WITNESSES Oct. 2, 19-51 J. H. GREEN MACHINE FOR APPLYING SPECULAR COATINGS Filed NOV. 27, 1948 WITNESSES:

( Wa g 6 Sheets-Sheet 6 INVEINTOR J: h. GREEN W A mm ATTORNEY Patented 2, 1951' MACHINE FOR APPLYING SPECULAR COATINGS James H. Green, West Orange, N. J., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 27, 1948, Serial No. 62,343

11 Claims. 1

This application is a continuation-in-part of my copending application Serial No. 671,545, flled May 22, 1946, now abandoned, and entitled Method and Apparatus for Applying Specular Coatings.

This invention relates to coating the interior surfaces of transparent vitreous envelopes with specular material, such as aluminum.

The principal object of my invention, generally considered, is to manufacture bulbs for heat, spot, flood, and sun lamps, and other devices in which radiant energy is to be reflected therefrom in a certain direction, by applying a specular coating of a metal, such as aluminum, for example, over a portion only of such bulbs, the remainder being kept clear to allow the radiant energy to freely emerge therefrom.

Another object of my invention is to coat bulbs for radiant energy devices with reflecting material, while portions thereof are covered with a suitable masking material to leave a translucent or transparent window in each bulb to thereby allow for the transmission of radiant energy in a desired direction.

A further object of my invention is to provide a machine for automatically adjusting the masking-material in the bulb, evacuating, flashing the specular material on the unmasked portion of the bulb, and unloading the coated bulb from the machine.

Other objects and advantages of the invention will become apparent as the description proceeds.

In the drawing:

Figure 1 is an elevational view, partlyin axial section, of a lamp of a type manufactured in accordance with my invention. a

Figure 2 is a side elevational view, partly in section, of a bulb used to make a lamp of a type similar to that illustrated in Figure 1 during the process of rotation to distribute masking material being fed thereto, as desired, over the end to be kept clear of a reflecting coating.

Figure 3 is an elevational view, partly in vertical section, of apparatus for evacuating a lamp bulb and flashing a reflecting coating thereon.

Figure 4 shows the masking material being poured out of a bulb after it has been removed a specular material may be vaporized onto a bulb, in accordance with my invention.

Figure 9 is a vertical sectional view on the line IX-JX of Figure '7, in the direction of the arrows.

Figure 10 is an elevational view of a doubleacting pinch valve for controlling the exhausting of bulbs in accordance with my invention, said valve being shown in open position, and a valve actuator on the machine being shown ready to move said valve to closed position, at position 2| on the machine.

Figure 11 is an elevational view of a similar valve illustrated in closed position, and a valve actuator of the machine being shown associated therewith in a position about to open said valve, also at position 2|.

Figure 12 is an elevational view of three of the valves for controlling the exhausting of bulbs, in accordance with my invention, on the lines )HI-XII of Figs. 7 and 9, in the direction of the arrows, associated apparatus being illustrated whereby the final exhaust is not applied if the preliminary exhaust valve has been manually or otherwise closed prior to a prospective change over from preliminary to final exhaust.

Figure 13 is a fragmentary sectional view on the line XIII-XIII of Figure 12, in the direction of the arrows.

Figure 14 is a fragmentary elevational view. with a part in section on the line XIV-XIV of Figure 12, in the direction of the arrows.

Figure 15 is an elevational view of a portion of the apparatus, showing how the masking material is applied to the bulbs, how it is distributed, and how the coated bulbs are finally removed from the machine.

Figure 16 is a fragmentary plan, with parts in section on the line XVI-XVI of Figure 15.

Figure 17 is an elevational view, with parts in section on the line XVII-XVII of, Figure 15, in the direction of the arrows.

Figure 18 is a fragmentary view of a finished bulb as it is discharged from the machine, and a detailed sectional view of a. device for receiving such a bulb, shown supported thereon, said device being shown in bulb-receiving position.

Figure 19 is a detailed sectional view, corresponding to Figure 18 but showing the device after the bulb holder thereof has been tipped to discharge the bulb from the machine.

In the previous manufacture of reflecting bulbs, for devices such as infra-red lamps and sunlamps, it has been the practice to flash specular material, such as aluminum, on the inner surface of the bulb and then dissolve a portion of said coating. so as to form a translucent or transparent window for the radiant energy to be distributed therefrom.

The purpose of my invention is to apply such a coating to the portion of each bulb as desired, leaving the remainder uncovered for the transmission of radiant energy, and thereby avoid the necessity for dissolving a portion of the coating after application.

' Form of Figures 1 to 5, inclusive Referring to the drawing in detail, like parts being designated by like reference characters, and first considering the embodiment of my invention illustrated in Figures 1 to 5, inclusive, there is shown in Figure l, a lamp l comprising an envelope or bulb i-l closed bya press l2 carrying an energy translating filament or other device i3, and having a base i4 which may be screwthreaded. The base-adjacent portion of the bulb is shown covered with a reflecting coating I5 on the inside thereof, which coating may be of aluminum or other specular material, preferably metal, flashed or vaporized thereon in a manner which will now be explained. The portion I6 of the bulb opposite the base is either clear or frosted, as desired.

' In practicing the process, I first take an open necked glass bulb or envelope H, such as shown in Figure l, or modified, if desired, as shown in Figure 2, and invert it as compared with its position in Figure l. A measured quantity i! of masking material, such an Aiundum powder, flne glass granules, or other heavy, fine, preferably non-metallic powder, or granular material is then poured therein, as from a receptacle i8 or other bulb. The powder H, which is desirably, although not necessarily what is called Barium Crown Glass Beads," preferably .014" in diameter, and between the limits of .014" and .017", as manufactured by Potter Bros. of Long Island, may be distributed in any desired manner, preferably while being poured, by having the bulb ii on a support I9 and, while the neck 2| is held by means 22 upright but unrestrained against rotation, the support I9 is rotated or oscillated by any desired means, such as a pulley 23 on a shaft 24 therefrom. The pulley is operated, as by a belt 25 from a motor, not shown, so that the powder IT is evenly distributed on the bottom, as desired, by centrifugal force to a predetermined cutoff line.

Referring now to Figure 3 there is shown evacuating apparatus 26 which may consistof a manifold 21, only a fragmentary portion of which is shown, each portion comprisin a head or cham ber 28 opening downwardly and carrying means for making an airtight connection with a bulb, such as a soft rubber mouthpiece 29. The mouthpiece is closed by elevating a masking-materialcontaining bulb Ii, from the dotted position to the full-line position, as by means of a platform or support 3| from which rack bar 32 depends. The rack bar is engaged by pinion 33 which may be operated manually by crank 34 and handle 35, and passes through a table or other support 36. Other means of elevating bulb H may be substituted if desired, such as air, motor or hydraulic cylinders.

Each chamber 23 also desirably has electrodes 31 and 33, between which may be mounted a container coil 39 of refractory metal wire such as tungsten, molybdenum, or similar material. In said coil is a desired quantity of specular material to be flashed on the bulb ll, such as one or more pieces 4i of aluminum sheet or wire. A deiii! sirable material is crimped aluminum ribbon, preferably that designated by the assignee as #3. As an alternative, the coil 39 may be replaced by a pot or container for the specular material, in turn enclosed in a high frequency induction coil for creating the desired heating effect. The flla- Y ment may be heated to flash the specular material onto the uncovered inner surface of the bulb, as by means of a variable transformer 42. The primary winding .43 is energized from the source of power 44 through switch 45, and the secondary winding 46 is connected to one of the electrodes, such as 38, by means of conductor 48. Said electrode 38 is electrically separated from the manifold 21 by insulating or glass cylinder 41. A voltmeter 49 is desirably used to show the applied potential. The other side of the line may be grounded at 5|, and the electrode 31 electrically connected to the manifold 21, grounded as indicated at 52.

Operation, referring to Figure 3 The manifold 21' and connected bulbs ii are evacuated, flrst roughly through valve 53 connectedgby pipe 54 to vacuum pump, such as one of the Kinney type designated 55. Desirably during the time gas is being removed from bulb II by Kinney pump 55, the radio-frequency coil is energized from an oscillator 86 for the purpose of ionizing said gas, thereby bombarding the inner surface of the envelope to get rid of moisture and occluded gases. At a predetermined period in this evacuation when the ionization has been reduced to a minimum, valve 53 is closed and valve 56 opened to finally evacuate the manifold and bulbs II, as by means of an oil diffusion pump 51, which may be one of the type designated VMF20 and manufactured by Distillation Products, Inc., 570 Lexington Ave., New York city 22, N. Y., and Kinney pump 55'. When a pressure of about 1 micron is reached, as shown by 9. micron or Pirani gauge 59 connected through a switch 6i to the source of power 44, the switch may be closed, while the transformer is adjusted to cause the coil 39 to first heat and slightly melt the aluminum, or other material 4| held therein, onto the supporting wire 39 in the envelope H.

The purpose of first slightly melting the aluminum, or other material to be applied to the bulb,

is to avoid an explosive flash which might damage the bulb and/or cause the coating material to be deposited non-uniformly thereon. After this coating material has been melted slightly, and before it has had a chance to run off the supporting wire, it is allowed to solidify on said wire. Then the transformer is adjusted to a higher voltage, the switch 45 is again closed, at this time vaporizing the aluminum or other coating material from the wire 39 to which it has adhered. The vaporization is thereby effected quickly but uniformly upon the uncovered surface of the envelope or bulb. It is essential that flashing of the coating material be of long enough duration to remove all of it from the heating coil.

Although only one envelope is illustrated, it will be understood that the evacuation of any convenient number of envelopes may be simultaneously effected and all of said envelopes coated simultaneously, or at about the same time, by flashing aluminum or other material thereon. In coating a series of envelopes, for example six, it is desirable to first apply approximately /2 voltage to the filaments in the envelopes. as by connecting adjacent pairs in series so that the aluminum, or other coating material, is first melted in the first pair, then in the second pair, and finally in the third pair, while the material in the preceding pair, or pairs. is allowed to cool. The voltage is then increased, as by changing the connections to similarly successively flash the pairs of filaments in the bulbs in parallel instead of series, thereby vaporizing the coating material upon the bulbs of the first pair, then upon the bulbsof the second pair, and finally upon the bulbs of the third pair.

After the coating operation has been effected, the apparatus is allowed to cool and the valve 6! opened to break the vacuum. The envelope I l and the other envelopes on the manifold 21 are then removed, and the Alundum or other material poured out, as illustrated in Figure 4, into another envelope, or if the masking material is to be tested, as is done at infrequent intervals, into a receptacle 33.

Embodiment of Figure 6 Referring now to the embodiment of my invention illustrated by the wiring diagram of Figure 6, there is shown a switch 94 connecting an adjustable auto-transformer 65 with a source of power which may be 110 volt, 60 cycle A. 0., represented by terminals 66 and 61, through fuses i8 and 69 or other circuit-breaking means. The auto-transformer is connected to the primary winding ll of transformer 12, through line I3 connected to one pole of the auto-transformer I5 and through fused line 13 connected to the adjusting terminal I5 of said auto transformer 85.

The secondary winding 16 of said transformer 12 is connected to change-over switch 11 which is for the purpose of changing the connection to the filaments 39 and 39". These filaments are only diagrammatically illustrated, but are supposed to be mounted in bulbs and carry aluminum or other specular material like the filament 39 in Figure 3. The filament 39, although shown as a single filament, may represent two or more filaments in parallel, each filament being mounted in its separate envelope, like the filament 39 in Figure 3, and a similar comment applies to the filament 39', although the operation is desirably as shown in Figure 3.

In using the apparatus illustrated in Figure 6, the switch 64 is first closed when the'switch TI is in a position as shown in full lines. The autotransformer contact is adjusted to give the desired voltage in the secondary winding 18 when the circuit is closed through the filaments 39 and 39". These filaments are first energized with the switch 'll in the position shown in full lines, so that the current flows from said secondary winding 16 through line 19, switch element 19, filament 39, line 8|, filament 39. switch element 32, and back to secondary winding 16 through line 33. This, of course, means that the filaments are first energized at half voltage or in series, so that the aluminum or coating material is merely melted.

If the pair of filaments, 39 and 39', represents only one unit of a series, as previously described broadly, then the next pair of filaments may be energized in the same manner through a similar arrangement, while the filaments 39 and 39 are allowed to cool. Finally, after all of said filaments have been so treated, or if there are no other filaments in the series after a pro-determined short-time interval allowing the coating material to cool, the switch 11 is moved from the This second energization of the filament at full voltage vaporizes the aluminum or other coating material thereon and effects the desired coating of the enclosing bulbs. This vaporization in the bulbs carrying the filaments 39 and 39, if merely a unit of a series may be followed by vaporization of the coating material carried by the filaments in successive pairs of bulbs, as was done in connection with the initial treatment of such filaments.

From the foregoing disclosure it will be seen that I have devised an improved method and apparatus for aluminizing bulbs, and particularly those of the R40 Sunlamp type. Although only a portion of the manifold is illustrated, it will be understood that it may involve six heads. Two or more of such manifolds may, if desired, be used on a single table or other support. The valves 53 and 58 may be of the hand operated on-ofi type, and the valve 62 is a simple airrelease valve. Under the inverted heads, the platform 3| raises and lowers for loading and unloading the bulbs. Although the drawing shows means for merely heating the coil 39 by the resistance thereof, it will be understood that high-frequency or radio-frequency power may be substituted for mere alternating or direct current, so that the metal used as a coating material may be inductively heated.

By my invention I have accomplished various results, as compared with the prior method of coating the entire bulb and then dissolving a portion thereof of the reflecting surface. One is the improvement in quality in connection with Sunlamp manufacture insuring at least a increase in ultraviolet output. A further improvement is that, when using radio-frequency as the ionizing means, the pumping time per load is reduced from 5 minutes to 3 minutes, or only of the normal pumping time is required. A further gain is an improvement in the hardness and adherence of the specular coating, and the improvement in its appearance by having a sawtoothed edge, the fineness of which depends on the size of the grains of masking material, rather than one which is unwavering. By using Alundum, a fine grain emery, or similar granular substance as the masking agent, four operations which existed in the previous manufacturing procedure have been eliminated, that is (1) the water wash ahead of the dissolving operation, (2) the dissolving of the metal coating on the bulb ends, (3) the after wash to neutralize the dissolving acids used, and (4) a baking operation to dry the bulbs.

Embodiment of Figures 7 to 19 Referring now to the embodiment of my invention illustrated in Figures 7 to 19, inclusive, there is shown a rotary conveyor 81 so constructed that it automatically aluminizes and then discharges finished bulbs. An associated rotary bulbpreparing machine or turret 88 is employed to load and level the masking material in each bulb to be aluminized. The machine 33 is driven from the same source of power as that which drives the conveyor 81. It distributes the masking material so as to insure that the deposit of the aluminum is cut oil or stopped at a desired plane. From this machine 88, the bulbs are transferred manually by the first operator, one at a time to the conveyor 81 which carries out the entire aluminizing operation, and finally at a point of near tangency between the circle of movement of bulbs on the conveyor and the circle of movement of bulbs on the turret, empties the masking material into another bulb, which is then prepared for in a similar manner for aluminizing. The only other manual operations are those of placing the aluminum, or other specularmaterial 89, in the flashing filament 9I, which is desirably a coil of tungsten, prior to placing the loaded bulb on the machine, and packing the aluminized bulbs, as they are discharged from the machine and inspected, in a suitable receptacle. Before describing the operation of the machine in detail, I will first describe the various parts thereof and the manner in which they operate.

The conveyor The conveyor81 comprises a base 92 on which is mounted a pedestal 93. Secured to said pedestal 93 is a generally circular platform member 94 serving as a support for various parts of the machine which will subsequently be described. On this platform member rests a generally annular supporting device 95, providing an annular tray 96, in which rest the manifolds 91, from which exhaust lines or pipes 98, 99, and IOI extend to the lower member I02 of valve I03 for connecting the various exhaust lines to the various heads I04 of the machine in sequence. this lower valve member I02 rests the upper member I05 of the valve I03, which moves with the rotary portion or spider I06 of the conveyor 81. The spider I06 comprises a central portion t 01, secured to an upright hollow drive shaft I08, and a main or body portion I09 to which a plurality of brackets III, in this instance twenty-four, are secured. Each bracket carries a device or head I04 for air-tight evacuating connection to, and deposition of coating material on, a bulb being processed.

f The shaft I00 carries at its lower end a gear H2 formed by a series of pivotally-mounted rustoconical rollers II3, successively engaged by the drive wheel I I4 on shaft IIS, which is driven from motor I I6, through belt II1 over pulley II8 mounted on shaft II9 which carries worm (not shown) meshing with worm wheel I2I secured on shaft I I5. The drive wheel I I4 is so formed that, as it turns, the gear H2 is kept stationary for the greater part of its revolution, but moves a step, that is, from one indexed position to the next, as an engaged roller II3 passes along the axially-curved trough portion I22 which joins the axially-oifset trough portions I and I30, as shown in Figure '1, whereby each head I04 of the machine is indexed in one position for a certain length of time and then promptly moved to its next indexed position.

Bulb-preparing turret The bulb-preparing machine or turret 8B is driven step by step, so that it indexes like the conveyor 81, by means of a cam I23 on the shaft I I5, which cam engages a roller I24 on a lever I25 secured by a pivot at I26 to a bracket I21 upstanding from the base 92 of the machine. The roller I24 is kept in engagement with the cam I23 by a coil 8 spring 90 acting between a bracket I00 on the other end of said lever and a bracket IIO on the base 92. Said other end of the lever I25 carries a pin I28 received in a slot I29 of the arm I3I of a bell-crank lever I32, connected by pivot pin I33 to base member I34 of bulb-preparing machine 88, which is in turn secured to base 92 as by bolts I35. The other arm I36 of bell crank lever I32 is connected through a pivot pin I31, rod I38, and pin I39, to lever I4I, pivoted about the main upright shaft I42 of bulb-preparing machine 88.

The shaft I42 carries a spider I43, comprising a column portion I44 through which the shaft I42 extends, and about which the spider rotates, and an annular platform portion carrying adjacent its periphery a series of rotatable shafts I46, on the top of each of which is mounted a bulb supporting member I41. Between the bulb-supporting members and the platform portion I45 are anti-friction means I48, such as rollers or ball bearings. The lower end of each shaft I46 carries a pinion I49 secured thereto, as by means of a pin I5I. Mounted on the upper end of the column I44, is a disc I52 carrying a series of plates I53, each of which is notched as indicated at I54, so that when a bulb I55 rests on a bulb-. supporting member I41, its neck may be disposed in the notch of the member I53 immediately thereabove, to insure that it is in a desired vertical position.

Step-by-step indexing motion of the spider I" is efiectecl by a ratchet I56 secured to the .bottom thereof, as by means of bolts I51, and engaged by a pawl I58 carried by the 1ever I4I, whereby movement of the lever back and forth effects indexing of the spider from one position to the next, in this instance, through V of a revolution, as the spider is formed to support eight bulbs. As will be understood, the ratchet I56 has the same number of teeth as the spider has bulb-supporting portions.

In order to effect a twirling movement of each bulb, after being loaded with masking material I59, sufficiently fast so that said masking material is distributed to a uniform cut-off plane, the pinions I49 are sequentially engaged by a gear segment I6I, pivoted about the shaft I42, and oscillated. This is effected by having an arm I62 on the segment i6I, connected by a flexible cable I63, passing through a guide to a pivot pin I65 in arm I66 of hell crank lever I61 pivoted to standard I68 extending from the base 92, by connecting pin I69. The other arm I1I of said lever I61 carries a roller I12 pivoted at I13 and held in engagement with a cam I14 by means of coil spring I15 acting between the arm HI and bracket I10 on standard I68. By virtueof the shape of the cam I14. as each pinion I49 comes into engagement with the gear segment I6'I as the spider I43 is indexed, the correspondingbulb support I41 is rotated back and forth twice about the axis of the bulb neck, thereby distributing the measured quantity of masking material I59 to a uniform cut-off level, as illustrated.

Flash-timing mechanism The shaft II5 also carries a gear I16, over which passes a chain I11 meshing with a corresponding gear I18 on a shaft I19 carrying a series of timing cams I8I, I82, and I83, respectively engaged by rollers I84 of timing switch elements I85. These cams I8I, I82,-and I83,only the second one of which is shown in detail in Figure 8, are adjustable as there indicated by each being formed of two relatively-rotatable cam segments I and I01, held in adjustable relationship by bolt I 88, so that the proportion of each revolution that the actuated switch member I85 is held against the cooperating switch member I09, may be regulated so that the filament 3| is energized for a desired length of time for flashing the enclosed specular material 09 therefrom.

A typical flashing circuit, representing circuit #2 at position I1, is,illustrated in Figure 8, comprising an adjustable auto-transformer ISI energized from a power circuit I02, through switch I93, and in turn energizing the primary winding I04 01 transformer I 95, the secondary winding I 30 of said transformer being connected to one of the leads I31 of a head I04, as said head is indexed at one of the positions I 0, I1, or III as shown in Figure 7, as by means of aflexible s1ipcontact member I00, the other lead I 93 being rounded as indicated at 20I. The other terminal of the secondary winding is grounded as indicated at 202, and a voltmeter 203 is disposed across the secondary-winding terminals so as to indicate the voltage adjustment.

Although I have shown three flashing positions, it is ordinarily unnecessary to use more than two, the third position being a standby and disconnected. The auto-transformer I9I is so adjusted that voltage at the first flashing position, numbered I6, is just suflicient to soften or barely melt the aluminum 8!, whereby it closely rests in consolidated condition on the flashing coil BI, ready to be vaporized at the next position, or that designated I1. It has been found in practice that about 4 or 5 volts may be applied to effect this softening or melting of the aluminum, while about to 10.5 volts is needed for the flashing operation at position I1.

Evacuating system The evacuating means, desirably a plurality of pumps such as those of the Kinney type, are connected to the exhaust manifolds 91 in any desired manner, and from there the vacuum system is lead to the outer exhaust pipes 204 and the inner exhaust pipes 205, both of which connect with the exhausting heads I04. In the present machine, there are in general two types of vacuum pipes, that is, those which form the preliminary evacuating system, and those which form the final evacuating system. The preliminary evacuating means is connected to the inner of the exhaust manifolds 91, and from there controlled by the inner passages of the valve members I02 and I 05, through the outer exhaust pipes 204, which connect-with the outer portions of the heads I 04.

The final evacuating means is connected to the outer of the exhaust manifolds and from there controlled by the outer passages in the valve members I02 and I05, through the inner exhaust pipes 205, in series with supplemental evacuating means, which in the present embodiment comprises oil diffusion pumps 206 which may be of the type VMF previously referred to. These pumps as illustrated, receive electric power through conductors I40 and I50, connecting through flexible contacts with slip rings I60 and I10, mounted on an insulating portion of the tray 35 and connected to a suitable source. A cooling system through which water circulates is provided for each pump 200 from supply pipe 208 to manifold 209, from whence it passes through pipe 201 to manifold 2I I, from whence it passes out through pipe 2 I 2.

A consideration of Figure 7 will show that the val loaded bulb I55. a received from the bulb-preparing machine 00, are fed to the conveyor 01 at a position such as that designated '23 or that designated 24, where the exhausting begins. A desirable way to start the preliminary exhaust is by means of a so-cailed megavac pump or house rough vacuum system, with plug constrictions in the connecting pipes so as to avoid initially destroying the vacuum in the system to too great an extent. A Kinney pump or pumps may, however, serve for preliminary evacuating, and such pump or pumps may be employed to, through the inner passages in the valve members I02 and I05, draw the air from the heads I04 to which the bulbs I are connected as shown in detail in Figure 8. A soft rubber facing 2I3 is used at each head to seal its engagement with the associated bulb.

This preliminary exhaust connection continues through position 1, as shown in Figure 7, whereupon at position 8 each bulb is successively switched on to final exhaust through the outer passages of the valve I03, making use of the diffusion pumps 206 and the inner exhaust pipes 205.

Pinch valves The pipes 204 and 205 are respectively controlled by port closers in the form of pinch valves 2I4 and 2I5, making two valves per head I04, as shown in detail in Figures 10, 11, and 12. These valves may be identical, but the valves 2 I4 for controlling the preliminary exhaust, shown in detail in Figure 11 and at the extreme right and left of Figure 12, are positioned on a circle of greater radius than the valves 2I5 for controlling the final exhaust, shown in detail in Figure 10 and as the middle valve of Figure 12, so that they are operated by different stops or roller cams on the machine. A consideration of these figures will show that each valve comprises a body casting 2I6, through which a flexible rubber vacuum hose 2I1 passes. The closing of the hose 2I1 is eflfected by a valve plate 2I8 pivoted at 2 I9, and controlled by a closing lever 22I, pivoted at 222, and having a short angular extension 223 carrying a roller 224 which engages the top surface of'the plate 2I8. As the lever MI is moved from the position shown in Figure 10 to that shown in Figure 11, as by a cam or stop 225 at position 2I on the machine, the plate 2I0 is moved down to compress the rubber hose 2I1, thereby closing the aperture therethrough and holding it in a compressed position.

The opening lever 226 of each valve is pivoted to the body casting 2I6 as at 221, and has a short extension 228 pivoted to a connecting rod 220, the other end of which is in turn pivoted to an intermediate portion of a prying member 23I carrying a roller 232, and connected with the body casting 2I6 by a pivot member 233. When the opening lever 226 is moved to the left, that is, from the position of Figure 11 to that of Figure 10, as by engagement of astationary member or roller cam 234 therewith at position 2| during rotation of the conveyor 81, the prying member aeeaess or roller cam 236, almost simultaneously but immediately thereafter opening the corresponding inner valve 215.

In order to take care of a situation where a head may not have a connected bulb 155, or where a connected bulb may have become broken due to the evacuating operationor for any reason, or where the operator for this or any other reason may have manually closed a valve 214,or provision is made for automatically closing such a valve upon the development of a leak, thereby preventing the pumping of a bulb, if in the corresponding head, or because a preliminary valve 214 was closed in order to prevent waste of power due to the absence or breakage of a bulb in said head, I provide means for automatically insuring that the final vacuum connection is not made. These means involve a feeler member 231 on reciprocating rod 238, moved by a cam 239 on shaft 115 (Figs. '1, 9 and 12). The cam 239 engages a roller 241 on an arm 242 of a crank 249 carried by a shaft 243, rotatable in a bracket 244 mounted on the base 92. The roller 241 is held in engagement with said cam 239 by a coil spring 245 acting between an arm 246 of said crank and a bracket 241 on the base 92.

This cam 239 thus causes the shaft 243 to oscillate and, through a crank 249 thereon, move a connected rod 249 with its arm 252 up and down in a bracket 251 carried by the platform member 94. The arm 252 slides on rod 238 against the action of light coil spring 253 thereon held between said arm 252 and a stop collar 254 on said rod. The coil spring 253 tends to push the collar 254 and connected rod 238 down,- so that the arm 255 mounted adjacent the top of the rod 238, and carrying an adjustable set screw 256, is caused to engage the top of the arm 252 as shown in Figure 12.

A mercury switch 251 in circuit with a solenoid 258, controlling the roller cam 236, and biased slightly toward open position by a light coil spring 259, is connected by a pivot 26! to a bracket 262 supported by the bracket 251, and provided with an arm 263 underlying the set screw 256. If on reciprocation of the rod 231 the feeler 238 finds the closing lever 221 closed, rather than in the normal open position represented in Figure 12, it will move down a relatively great distance, rather than the small distance indicated by the arrow 264, and cause the set screw 256 to engage the arm 263, and effect closure of the mercury switch 251, energization of the/solenoid 258, and consequent raising thereby of the roller cam 236, through the distance represented by the arrow 269. This prevents engagement of said cam 236 with the opening lever 226 of the corresponding valve 215 to the final vacuum system.

Thus, if one of the valves 214 has been closed for any reason prior to reaching position 1, the feeler 231 will move downwardly a greater distance than that represented by the arrow 264, or one sufficient to effect closure of the mercury switch 251, thereby raising the cam 236'to its upper position in order to avoid opening the corresponding valve 215. This means that the mercury switch 251 has been moved counterclockwise, as represented in Figure 14, to closed posi-' tion. Because the spring 259 i very light, the switch would tend to stay in that position, thereby preventing desired opening of subsequent valves 215 and initiation of the final exhaust, even though the next valve 214 is in open or normal position. I

In order to avoid such an undesirable situation, I provide a roller cam 169 disposed a slight distance counterclockwise beyond. but on the same circumference as the cam 236. This cam 199 is pivoted to a lever 199, in turn pivoted to a bracket 299 and adapted to roll over the upper face of each lever 221, in the closed position represented in Figure 12. Engaging the top of this cam is a rod 219 reciprocating in the bracket 299 and carrying an arm 219 near its upper end. The rod 219 also carries an outstanding post 229 connected by a coil spring 239 to a corresponding post 269 on the bracket, whereby said rod is urged downwardly into engagement with the roller 169.

The arm 219 carries a set screw 299 locked in adjusted position by a nut 399. The mercury switch device 261 carries an arm 391 normally overlying the set screw 299, as shown diagrammatically in Figure 14, so that if the mercury switch 261 is closed as the roller 1811 is engaged by the lever 221, the rod 219 as it is pushed upwardly causes the set screw 289 to engage the arm 391 and, assisted by the coil spring 259, trips the mercury switch back to normally-open position as in Figure 14.

The high frequency control At positions 4 and 5, or at such positions where the pumps have reduced the pressure in the bulbs being evacuated to between 25 and '15 microns of mercury, I may provide high-frequency coils 265 and 266 carried in an enclosure 261 which is moved up to surround the bulbs 166 to be aluminized as they are indexed, and moved down out of the way to clear the bulbs while they are being moved from one position to the next. The moving means for this control comprises a lever-263 pivoted about the shaft 243 and its outer end moving the high frequency coils up and down, while its inner end carries a roller 266 engaging a cam 211 mounted on shaft 1 15, whereby the movement of the lever is synchronized with the indexing of the heads 194.- The coilmoving means desirably includes a switch for energizing the coils 265 and 266 only when they surround indexed bulbs. The frequency of the energizing power is desirably between kilocycles and 30 megacycles.

Unloading of bulbs Figures 15 to 19, inclusive, show details of the apparatus which acts to receive each bulb 156, as the vacuum thereto is broken after the aluminizing is complete, and discharge it into a chute 212, from which it is removed by the operator preparatory to being used, as for making a lamp. This apparatus involves a bulb holder 213, connected by a pivot pin 214 to a terminal casting 215, carried by a pair of rods 216 which reciprocate in bracket 211 mounted on base 92. Reciprocation is effected by a connection with the end of the lever 125, through link 218 and connecting pivot 219, to a crosshead 261 to which the lower ends of the rods 216 are secured, by means of pivot pin 282.

In order to adjust the normal position of the bulb holder 213, a set screw 283 is provided extending from the casting 215 to the bottom face of the holder 213, and locked in adjusted position by nut 284. Tilting of the bulb holder 213, to the unloading dotted-line position represented in Figure 15, is efiected by a post 285 carried by the bracket 211 and upstanding between the reciprocating rods 216, so that as said rods descend amass:

13' carrying the'holder 278 therewith, the' roller 288 mounted on the top of the rod 285 engages the cam surface 281 on the bulb holder 218, and tilts the latter to upset and discharge the bulb I55 carried thereon into the chute 212.

A gate 288 in said chute is provided to automatically stop each bulb I55 as it i received, and release it prior to reception of the next bulb. .This gate is pivoted to the chute 212 as indicated at 288, and has an arm 28I extending in a diagonal generally-opposite direction therefrom and actuated, as the rods 216 move up and down. by connected lever 282 urged downwardly by coil spring 298 acting thereon from an intermediate portion of one 01 the supporting rods 284 extending from the bracket 2'" to the chute 212. Movement is transmitted to the lever 282 to periodically close the gate 288 by connecting rod 285 provided with a slot 288 receiving a pin 28! outstanding from the bracket 2'", and with an angle clip 290 secured to its lower end. as by a rivet 298, and actuated by engagement of the crosshead 28I therewith during part of the movement of the latter. The upper end of the connecting rod 285 is connected by pivot pin 288 to an intermediate portion of the lever 282. The lever has one end connected to the bracket 21'! by a pivot pin 30I, and its other end provided with a slot 302 receiving a pin 303 outstanding from the arm 28I of the gate 288. It will thus be seen that during the upper portion of the up and down movement of the rods 216, the gate is synchronously opened and closed.

The chute 212 is disposed over the bulb-preparing machine or turret 88 and provided in its bottom with a funnel 304 so that as each bulb is overturned and placed in the chute, the masking material therein is discharged therefrom into a bulb in said turret, thereby reusing the masking material.

Operation, referring to Figures 7 to 19 In the present embodiment, the conveyor machine 8'! has 24 heads and thus the same number of indexing positions, numbered I to 24. It is desirably set for index every 8 seconds. Because of the connection of the bulb-preparing machine or turret 88 thereto, a bulb on this turret is also moved from one position to the next every 8 seconds. The coating operation should be started with a supply of washed and dried bulbs, each containing a measured quantity of the masking material. At least 24 bulbs so provided and a number of extras should be on hand before ,starting. The bulb-preparing turret 88 should be loaded with a bulb in each position, and after.

each bulb is twirled to properly distribute the masking material, it is by hand moved to the coating machine 81. We will now follow the operation' of a bulb from when it is first loaded on the machine to its discharge therefrom.

Two operators are employed, number 1 to insert the specular material, such as aluminum foil 09, in the refractory metal heating coil 8| and the prepared bulb in the head, and number 2 to prepare the bulbs for the turret 88 and receive the aluminized bulbs. After placing the foil 89 and 14 removing a bulb from the preparing turret", after the masking material has been properly dis tributed therein, it is placed in a head I04, at position 23 or 24 of the machine, the assembly of such a bulb in a head being shown diagrammatically in Figure 8. The suction at the loading position holds the bulb I55 in place. The antileakage soft rubber mouthpiece or connector 2I3 serves to insure against leakage between the bulb and head, and the vacuum connection is made by having the corresponding preliminary pinch valve 2 open. The bulb travels step by step to position 4, while being preliminarily exhausted.

At position I, if the radioor high-frequency treatment is being employed, it is surrounded by the high-frequency coil 285 energized so as to ionize the gas therein and facilitate evacuation. This high-frequency treatment also has other desirable effects, as described in connection with the first embodiment. The treatment may be repeated at position 5. After the bulb arrives at position I, a change over from the preliminary evacuation to a final evacuation at position 8 is effected. That is, the corresponding outer valve 2I4 is closed, while the corresponding inner valve 2I5 is opened, by the roller cams 235 and 238, respectively. Because of the machine operating counter-clockwise, and the inner valve for each head being thus somewhat in advance of the outer valve for said head, and inasmuch as the cams 235 and 235 are on the same radiusat position 1, the opening lever 226 of the valve 2.I5 is engaged before the closing lever 22! of the valve 2I4. As shown in Figure 12, said levers are, when the valve H5 is closed and the valve 2I4 open, on approximately the same radius, so that because of the difference in the throw of the lever 2 as compared with that of the lever 226, there is a connection to the final-vacuum system eifected almost simultaneously with, but a very small interval of time after, a closing of the preliminary evacuating line.

The bulb then passes through positions 8 to I5, inclusive, and finally reaches position I18, where the enclosed filament 9I is given a moderate electrical energization so that the aluminum foil, or other specular material 89 therein, is barely melted without appreciable vaporization or other losses therefrom. At the next position IT, a higher electrical energization is given to the coil 8|, or one to vaporize the aluminum or other specular material therefrom. thereby completing the coating operation. Position I8 is a standby flashing position which is ordinarily used for cooling. Positions I9, 20, and 2| are also employed for cooling. Between position H and po sition 22, the final vacuum valve 2I5 is closed by the cam 225 and the preliminary vacuum valve 2 opened by the cam 234, as represented in Figures 10 and 11, to by virtue of the construction of the valve I03 at this point, break the vacuum; allowing air to come into the bulb through the pipe 284.

The breaking of the vacuum in the bulb allows it to drop the distance represented by the arrow 305 in Figure 15, onto the bulb holder 213, which shortly thereafter descends to the dotted position illustrated in Figure 15. This action overturns the bulb I55 onto the chute 212, where it is momentarily stopped by the gate 288, while the masking material therein is discharged through funnel 304 into a bulb I 55 immediately therebelow, to thereby fill it with the desired quantity of masking material. By virtue of this operation, it is unnecessary to have a' great quantity of bulbs filled with masking material, or

" moved periodically and cleaned.

any great amount of masking material for the purpose. It is, however, desirable to periodically clean the masking material by sieving to remove contaminations due to the operation of the machine. Prior to the next bulb reaching the unloading position, the gate 288 is lowered allowing the bulb under consideration to slide down the chute 212 to be received by an operator.

In order to insure the desired results, the machine should be kept reasonabl clean of masking material, dirt, and oil, at all times. The guards 305 which are desirably employed around the path of the bulb to protect the operators, and which may be formed of cellulose acetate or other similar transparent material, are desirably re- The bearing surfaces and cams should also be kept reasonably clean and lubricated. The pumps, of course, should be kept in good condition and the degree of vacuum during operation may be indicated by a Pirani gage (not shown). The rubber mouthpieces 2l3 of the heads I04 may be cleansed by means of a clean lintless cloth soaked in acetone, and then wiped dry with a clean lintless cloth.

Although preferred embodiments of my invention have been disclosed, it will be understood that modifications may be made within the spirit and scope of the appended claims.

I claim:

1. Apparatus for coating predetermined portions of' the inner surfaces of open-necked glass bulbs, comprising means for holding said bulbs with their open necks upward and containing granular masking material in the bottoms thereof, means comprising anti-leakage mouthpieces connectable with bulbs through their open necks and supported refractory means which then depend through said necks for holding and heating said coating material, for connecting said open necks to exhausting means for producing a vacuum in said bulbs, and at the same time positioning said holding and heating means in said bulbs while surrounding material with wh ch the bulbs are to be coated, means for energizing said refractory means to flash the material on said bulbs, and means for then breaking the vacuum to allow for removal of said bulbs from the machine.

2. Apparatus for coating predetermined portions of the inner surfaces of open-necked glass bulbs, comprising means for holding said bulbs, means comprising a chamber opening downwardly and terminating in a soft rubber mouthpiece and electrodes depending in said chamber through said mouthpiece and supporting means for holding and heating said coating material, for connecdng said Open necks to exhausting means for producing a vacuum in said bulbs, and at the same time positioning said holding and heating means in said bulbs and surrounding material with which the bulbs are to be coated, means for energizing said electrodes to flash the material on said bulbs, and means for then breaking the vacuum to allow for removal of said bulbs from the machine.

3. Apparatus for coating with specular material predetermined portions of the inner surface of open-necked glass bulbs, comprising a chamber opening downwardl and terminating in a soft rubber mouthpiece, electrodes depending in said chamber through said mouthpiece and supporting means for holding and heating said coating material, a vertically movable support for a bulb, means for operating said support L cause it to raise or lower a bulb from said chamber, so that its neck enters said chamber and the electrodes enter said neck when raised, whereby the soft rubber mouthpiece engages said bulb below said neck to effect a vacuum-tight seal, means for exhausting said chamber in order to-remove the air from said bulb, means for energizing said heating means to flash the coating material onto said supported bulb, and means for breaking the vacuum to said chamber to release the bulb.

4. Apparatus for coating predetermined portions only of the inner surfaces of open-necked bulbs, comprising a rotary conveyor, means for rotating said conveyor step by step and indexing it between each step of its rotation, a plurality of exhaust heads on said conveyor, each comprising a chamber opening downwardly, termimating in an anti-leakage mouthpiece engageable with a bulb around its neck, and formed with leads to support a coil for holding bulb-coating material, a vacuum valve associated with said conveyor, vacuum lines from said valve to said heads, one line to each head being for preliminary exhaust and the other for final exhaust, means in the final exhaust line between said valve and each head for improving the vacuum effected, means at one position on said conveyor for automatically switching over from the preliminary to the final vacuum system, means at another position for subjecting a coil in a head to energization to barel melt bulb-coating material enclosed therein, means at the next succeeding position to flash said coating material from said coil onto the bulb, and a bulb holder at a succeeding position for after cooling and breaking the vacuum, receiving said bulb, a discharge chute.

5. Apparatus for coating predetermined portions of the inner surfaces of open-necked glass bulbs, comprising a turret on which a plurality of said bulbs holding granula masking material may be disposed with their open necks upward, a rotatable support on said turret underlying each bulb, means for indexing said turret to move each bulb from one position to another, means in one position for twirling the underlying support so as to distribute said masking material in said bulb to a predetermined level, a ro.ary conveyor portion of a coating machine adjacent said turret, means for rotating said conveyor portion step by step and indexing it between each step of its rotation, a plurality of exhaust heads on said conveyor, each comprising a chamber opening downwardly, terminating in an anti-leakage mouthpiece engageable with a bulb around its neck, and formed with leads to support a coil for holding bulb-coating material, a vacuum valve associated with said conveyor, vacuum lines from said valve to said heads, one line to each head being for preliminary exhaust and the other for final exhaust, means in the final exhaust line between-said valve and each head for improving the vacuum efiected, means adjacent said conveyor for at a given indexed position, subjecting each bulb in its head to high-frequency treatment, means at another position for au omatically switching over from the preliminar to the final vacuum system, means at still another position for subjecting a coil in a head to energlzation to barely melt bulb-coaing material enclosed therein, means at the next succeeding position to flash said coating material from said coil onto the portion of the bulb not covered by said masking material, means at 'a succeeding position for, after cooling, breaking the vacuum 17 to said bulb, allowing it to drop onto a holder, lowering said holder, and tipping said bulb onto a discharge chute, where it first pours the contained masking material into an empty bulb held on said turret.

6. Apparatus for coating with specular metal predetermined portions of the inner surface of open-necked glass bulbs, comprising a chamber opening downwardly and terminating in a soft rubber mouthpiece, leads depending in said chamber through said mouthpiece and supporting a coil of tungsten for holding and heating a small quantity of said metal, a vertically movable support for a bulb, means for lowering said bulb from said chamber, or raising said bulb to said chamber so that its neck enters said chamber and the leads enter said neck, whereby the soft rubber mouthpiece engages said bulb below said neck to effect a vacuum-tight seal, means for exhausting said chamber-and bulb, and means for energizing said coil to flash the metal onto said supported bulb.

7. Apparatus for coating predetermined portions of the inner surfaces of open-necked bulbs, comprising a rotary conveyor, means for rotating said conveyor step by step and indexing it between each step of its rotation, a plurality of exhaust heads on said conveyor, each com rising a chamber opening downwardly, terminating in an anti-leakage mouthpiece engageable with a bulb around its neck, and formed with leads to support a coil for holding bulb-coating material, a pinch valve associated with said conveyor, said valve comprising a body casting, a flexible rubber vacuum hose passing therethrough, a valve plate pivoled to said body casting, a closing lever pivoted to said body casting and having a short angular extension carrying a roller which engages the top surface of said valve plate so as to compress the rubber hose and close the aperture therethrough, an opening lever pivoted to the body casing and having a short extension, a pry ing member carrying a roller and pivoted to the body member, and a connecting rod with one end pivoted to an intermediate portion of said prying member and the other end pivoted to the end of said opening lever extension, said prying member carrying a roller engaged by the closing member when closed, whereby when said prying member is rotated, its roller pushes up on the closing lever until the latter is snapped open by the resiliency of the rubber hose acting upward on the valve plate, vacuum lines from said valve to said heads, one line to each head being ifor preliminary exhaust and the other for final exhaust, means in the final exhaust line between said valve and each head for improving the vacuum effected, means at one position on said conveyor for automatically switching over from the preliminary to the final vacuum system, means at another position for subjecting a coil in a head to energization to barely melt bulb-coating material enclosed therein, means at the next succeeding position to flash said coating material from said coil onto the bulb, a bulb holder at a succeeding position for after cooling and breaking the vacuum, receiving said bulb, a discharge chute, and means for lowering said holder and tipping said bulb onto said chute.

8. Apparatus for coating predetermined portions of the inner surfaces of open-necked glass bulbs, comprising a turret on which a plurality of said bulbs holding granular masking material may be disposed with their open necks upward, a rotatable support on said turret underlying each sw m 18 bulb, means for indexing said turret to move each bulb from one position to another, means in one position for twirling the underlying support so as to distribute said masking material in said bulb to a predetermined level, a rotary conveyor portion of a coating machine adjacent said turret, means for rotating said conveyor portion step by step and indexing it between each step of its rotation, a plurality of exhaust heads on said conveyor, each comprising a chamber opening downwardly, terminating in an anti-leakage mouthpiece engageable with a bulb around its neck, and formed with leads to support a coil for holding bulb-coating material, a vacuum valve associated with said conveyor, vacuum lines from said valve to said heads, one line to each head being for preliminary exhaust and the o.her for final exhaust, means in the final exhaust line between said valve and each head for improving the vacuum effected, means adjacent said conveyor for at a given indexed position, subjecting each bulb in its head to high-frequency treatment, means at another position for automatically switching over from ,he preliminary to the final vacuum system, means at still another position for subjecting a coil in a head to energization to barely melt bulb-coating material enclosed therein, means at the next succeeding posi ion to flash said coating material from said coil onto the portion of the bulb not covered by said masking material, and means at a succeeding position for, after cooling, breaking the vacuum to said bulb, allowing it to drop onto the holder of unloading mechanism comprising a pair of vertically reciprocable rods, a verminal casting connecting the upper ends of said rods, said holder being pivotally carried by said terminal casting, means for reciprocating said rods in synchronism with the indexing of said coating apparatus, and means for tilting said bulb holder as the rods move downwardly, comprising a stationary portion disposed between said rods and engaging a lower portion of said bulb holder, a chu e disposed adjacent said unloading mechanism and onto which each bulb is periodically upset and fed there .0, and a gate pivoted toalower portion of said chute so as to stop each bulb as it first passes to said chute, and then release it move down said chute prior to the reception of the next bulb.

9. Apparatus for coating predetermined portions of the inner surfaces of open-necked glass bulbs, comprising a rotary conveyor, means for rotating said conveyor step by step and indexing it between each step of its rotation, a plurality of exhaust heads on said conveyor, each comprising a chamber opening downwardly, terminating in an anti-leakage mouthpiece engageable with a bulb around its neck, and formed with leads to support a coil for holding bulb-coating material, a vacuum valve associated with said conveyor, vacuum lines from aid valve to said heads, one line to each head being for preliminary exhaust and the other for final exhaust, means in the final exhaust line between said valve and each head for improving the vacuum eilected, means adjacent said conveyor for at a given indexed position, subjecting each bulb in its head to high-frequency treatment, means at another position fo automatically switching over from the preliminary to the final vacuum system, means at still another position for subjecting a coil in a head to energization to barely melt bulb-coating material enclosed therein, means at the next succeeding position to flash said coating 19 material from said coil onto the bulb, means at a succeeding position for, after cooling, breaking the vacuum to said bulb, allowing it to drop onto a holder, lowering said holder, and tipping said bulb onto a discharge chute.

10. Apparatus for coating predetermined portions of the inner surfaces of open-necked glass bulbs, comprising means for preparing such bulbs for coating said predetermined portions thereof, said means comprising a rotatable turret on which a plurality of said bulbs may be disposed in a circle about the turret axis of rotation with their open necks upward, an individually rotatable support on said turret underlying each bulb, a rotary conveyor portion of a coating machine with devices adapted for evacuation and deposition of coating material on said bulbs, disposed in a circle about the conveyor axis of rotation for receiving a plurality of said bulbs holding granular masking material so spaced from said turret axis that, at a point of near tangency between said circles, a bulb on the conveyor portion may be upended to transfer contained masking material therefrom to an adjacent bulb on said turret, means for simultaneously rotating said conveyor portion and said turret step by step from one position to the next, and means at one position on said turret for twirling a rotatable bulb support sufliciently fast to disLribute granular material in the supported bulb to a predetermined level, preparatory for transfer to an adjacent evacuating and coating device of said rotary conveyor.

11. Apparatus for coating predetermined portions of the inner surfaces of open-necked glass bulbs, comprising a rotatable turret on which a plurality of said bulbs may be disposed in a circle about the turret axis of rotations with their open necks upward, an individually rotatable support on said turret underlying each bulb, a rotary conveyor portion of a coating machine with heads disposed in a circle about the conveyor axis of rotation for receiving a plurality of said bulbs holding granular masking material so spaced from said turret axis that, at a point of near tangency between said circles, a bulb on the conveyor portion may be upended to transfer contained masking material therefrom to an adjacent bulb on said turret, means for simultaneously rotating said conveyor portion and said turret step by step from one position to the next, means at one position on said turret for twirling a rotatable bulb support sufliciently fast to distribute such granular masking material in the supported bulb to a predetermined level, means for then holding said bulbs with their open necks upward and containing the distributed masking material in the bottoms thereof for transfer to an adjacent head of said rotar conveyor, whereby they are successively connected to exhausting means for producing a vacuum therein, means on said heads for, when said bulbs are connected thereto, positioning heating means therein surrounding material with which the bulbs are to be coated, means for energizing said heating means to flash the coating material on said bulbs, means for then breaking the vacuum to remove said bulbs from the machine, and means for then upending said bulbs one by one to transfer the granular masking material therefrom to an empty bulb on said turret.

JAMES H. GREEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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