US2304859A - Coating apparatus - Google Patents

Description

Dec. 15, 1942. R. F.- STRICKLAND ETAL COATING APPARATUS Filed Feb. 14, 1940 r w /95 20 20/ 1 5? m 4 Sheets-Sheet l Inventor's Rogat F. Strickland,

.Fr-ank J. Mall og, Gerald W. Fbvall',

071 heir' Attorney.

Dec. 15, 1942. R, F. STRICKLAND El'AL 2,304,859

COATING APPARATUS Filed Feb. 14, 1940 4 Sheets-Sheet 2 Invencors:

Royal F. StrickLand, Frank J.MaLLo9,

er [d W. PovalL b Their- Attorneg.

COATING APPARATUS Filed Feb. 14, 1940 4 Shets-Sheet s ,U Ha ww m 5 aP w W H @5 m w n e m .n F

Inventors Rogal F. Strickland,

er" b Patented Dec. 15, 1942 COATING APPARATUS Royal F. Strickland and Frank J. Malloy, Cleveland Heights, and Gerald W.. Povall, East Cleveland, Ohio, assignors to General Electric Company, a corporation of New York Application February 14, 1940, Serial No. 318,962

.13 Claims. (Ciel-12.2)

Our invention relates to apparatus for coating a body or base member with reflecting materials, and more particularly to automatically operable apparatus for causing the evaporation, in an evacuated space, of a reflecting material, such as aluminum, and its subsequent condensation onto the interior surfaces of the vitreous enclosures or bulbs for incandescent lamps or similar articles.

Heretofore, as far as we are aware, the deposition of a metallic reflecting coating by vaporization onto a supporting body or base member for the coating material is injured and must be replaced before the apparatus can be used again. Other objects and advantages of our invention will appear from the following detailed description of a species thereof and from the accompanying drawings.

In the drawings, Fig. 1 is a plan view of apparatus comprising our invention with the major purposes of producing a specular reflector has involved laboratory procedure and has been done in a relatively slow uneconomical manner. The principal object of our invention is to provide apparatus for this purpose having a high rate of production and requiring only the feeding and the removal of the articles to be coated, and the insertion of the reflecting material. Such apparatus must produce a satisfactory reflecting coating with a high degree of regularity in order to be commercially practicable.

Another object of our inventionis to provide apparatus for the satisfactory coating of cupshaped vitreous bodies such as used for the re-' flector sections of incandescent lamps of the type disclosed in Patent 2,148,314, D. K. Wright, assigned to the assignee of the present invention.

Such bodies are diflicult to coat evenly because of their shape, and must have a very uniform coating because of their nearness to the light source which causes any defects to be very conspicuous.

Another object of our invention is to provide, in combination with the above type coating apparatus, means for automatically preventing the heating of the reflecting material and thevconsequent vaporization thereof should the space in which the vaporization takes place be improperly evacuated. According to our invention, the supporting body or base member to be coated is evacuated directly so that it, together with a portion of the apparatus, constitutes the vacuum chamber and'any incorrect positioning of thesaid body or base member produces a leaking condition. Such a condition may also be produced when, for some reason, one of said bodies has not been inserted in the apparams or 'when an imperfect body which allows air to leak in is carried by the apparatus. Such a condition is objectionable because the quality of the vacuum affects the distribution of the coating material to a considerable extent. Moreover, if the vacuum is poor enough, the heater for vaporizing portion of a turret, comprising part of the apparatus, broken away to show the underlying mech anism; Fig. 2 is a vertical section of the apparatus taken along line 2-2 of Fi 1; Fig. 3 is a horizontal section, taken along the line 3-3 of Fig. 2, of one of a plurality of heads carried by said turret; Fig. 4 is a perspective view, on an enlarged scale, showing a strip of metal, to be vaporized supported by a heater coil thereforev which is shown in dotted lines; Fig. 5 is an end view of a pinch clamp shut-off means provided for each head; Fig. 6 is a perspective view of the lower half of a rotary valve for controlling exhausting and gas filling operations of the head; Fig. '7 is a plan view of operating means for a pinch clamp closing portion of a leak detecting mechanism; Fig. 8 is a vertical section therethrough along the line 8--8 and in the directions indicated; Fig. 9 is a diagrammatic view of a vacuum-quality testing mechanism and pinch clamp closing means operated thereby; Fig. 10 is a side view of the first three of a number of contact-making mechanisms engaged by the heads, as viewed from line Ill-I0 Fig. 1; and Fig. 11 is a perspective view of switching means for controlling the operating period of the heaters in combination with a diagram of the other parts in the electrical circuit to one of said heaters.

In the species of our invention shown in the drawings. a plurality of heads l5 are provided for carrying the vitreous cups l6 through the various steps in the cycle of operation thereof. Only three of the heads l5 appear in Fig. 1, although a plurality (sixteen) of such heads are mounted at regular intervals at the periphery of the, two-part turret I'I which rests on the flange l8 (Fig. 2) of the hollow center column IQ of the apparatus. The center column I 9 extends upward from stationary frame 20 of the apparatus which spreads outward underneath the entire center portion of the turret I l as shown in Fig. 1 and is supported by the engagement of the lower face of said flange l8 with the ball bearing 2| on said frame 20. 'The motion of the turret ll occurs in repeated indexing moveby a central driving means (not shown) which engages the lower end of the center column I9 and which provides for the operation of mechanisms at the various stations taken by the heads I6.

The cycle of operation of the apparatus begins at station A at which an operator inserts a piece of the coating material to be vaporized and the vitreous cups I6 which are tobe coated. Each head I5 accommodates two of the cups I6 at one time and, accordingly, the operator first inserts a body 22 of the coating material into each of the two coiled portions 23'-23' of the (tungsten) heater 23 (Fig. 3) which are located on opposite sides of the head I5. The body 22 of the coating material in this particular instance, amounts to a thin strip of aluminum weighing .044 gram which, as shown in Fig. 4, is bent back on itself and corrugated so that each corrugation engages a turn of the coil 23. The said heater coils 23' are located along the central axis of the central opening 24 in the ring or drum-shaped body portion 25 of the head I5. The ends of the heater 23, as shown in Fig. 3, are located in openings in the split ends of the rods 26 which are drawn tight thereabout by the tapered sleeves 21 and are adapted to be easily removed therefrom following the unscrewing of the sleeves 21 to allow replacement of the heater 23. The rods 26 function both to support the heater 23 and carry electrical energy to it and each rod is mounted in insulating bushings 28. and 28' located respectively, in the threaded compression sleeve 29 and an opening in the body portion 25 of the head I5. The said sleeves 29 allow the rubber washers 30 and 3| to'be pressed against the flange 26' on the rod 26 and seal the said opening in the body portion 25.

The vitreous cups I6, now inserted into the head I5, may be those used for the reflector section of a lamp of the type disclosed in Wright Patent 2,148,314, hereinbefore referred to. At this particular stage in the manufacture of the lamp, each cup-is provided with a vitreous exhaust tube 32 sealed over an opening in the center of the end portion of the cup, and metal terminal elements 33 (two, in this instance) sealed over openings at diametrically opposite points on said end portion from the xhaust tube 32. The terminal elements 33 hermetically seal the openings in the cup I6 directly associated therewith, but the exhaust tube 32 does not, so that a stopper such as provided by the rubber tube 34 which is closed off by the plug 35 is preferably slipped over the end thereof to seal the only remaining opening in the cup I6 before it is inserted into the apparatus.

Insertion of each cup I6 is permitted only after the holder 36 is pulled back by pressure on the arm 31, and consists in resting the outer rim or edge of th cup against a rubber sealing gasket 39 on the face of the boy 25 of the head I5. The holder 36 and the arm 31 are mounted on the rod 39 carried by the bracket 40 and are then allowed to turn back so that the holder 36 engages said cup and keeps it in position. To allow this movement of the holder 36, the cup I6 must be orientated so that the lowermost terminal element 33 falls in the center opening in the holder 36. The closing movement of the holder 36 is produced by the contraction of the spring H which extends between a bolt in the lower part of the head I5 and said holder 36 and does not change the position of the bracket 40 which is attached directly to the turret I1. The gasket 38 is held in place on the body 25 of the head I5 by the ring 4| which is engaged by bolts screwed into said body 25 and extending through the gasket 38 and the ring 4 I The center aperture in the ring M is just large enough to allow easy passage of the outwardly flared edge I6 of the cup I6 and serves to position said cup so that the heater 23 is at the exact center of the opening therein. The time interval of the movements of the turret I1 are such that the head I5 is moved to station B directly following the insertionof both metal strips 22 and both cups I6.

The indexing movement of the head I5 into station B starts the cycle of operation of the apparatus as the upper half 42 of the rotary valve which is located below the center of the turret I1 (Fig. 2) is turned therewith and connects a source of vacuum to said head I5. The hollow interior of the body 25 of the head'I5, and the cups I6, are connected to the rotary valve through the passage 43in said body 25 which continues into the tube 44 extending downward through the turret I1, the pipe 45 which extendssidewardly from tube 44, the rubber tube 45 which is part of the valve or pinch clamp 41, the pipe 48 and the rubber tube 49 which makes the connection to the pipe nipple 49' extending from the passage 50 in the upper half 42 of the rotary valve. Each head I5 is similarly connected to a passage in the rotating upper half 42 of the rotary valve which is made to turn with the turret I1 by the pin 5| and depends on the movements of said upper half 42 with respect to the lower half 52,

shown in detail in Fig. 6, for the proper sequence of operations necessary to clear the interior of the cups I6 of gas and vapor. At station B, the passage 50 is aligned with a passage 53 in the lower half 52 of the rotary valve connected to a source of vacuum (not shown) and it is not until the head I5 is indexed to station C (only indi cated in Fig. 1) that the succeeding operation also brought about by movement of the upper half 42 of therotary valve takes place.

The movement of the rotary valve occurring during this latter index aligns the passage 58 with passage 54 which connects the head I5 to the valve 55 of the pinch clamp closing apparatus shown in Figs. 1, 7 and 8 and, asdiagrammatical- 1y shown in Fig. 8, to the manometer 56 which make up the leak detecting mechanism. These parts function only when the head I5 is not closed off by the cups I6 as may happen for example, when one or both of the cups I6 have not been inserted or have been improperly inserted therein or when an imperfect cup I6 produces a leaking condition. Should the head I5 be leaking, the mercury 51 in the monometer 56, which i already connected to one side of the electrical line by the wire 58, moves upward and into contact with the wire 59 completing the circuit through the coil of the solenoid 60 which is connected to the other side of the line by wire 6I. The solenoid 68 is mounted on the rod 62 extending from the bracket 63 on the frame 20 through the bracket 64 and through movement of its armature 65 controls all further operations of the leak detecting mechanism.

When the circuit to the solenoid 60 is closed and the armature 65 is moved, the rod 66 is forced upward turning the arm 61, the shaft 68 on which it is mounted and the latch 69 so that the pulley 10 is freed and the weight 1 I turns it in a counter-clockwise direction. The latch 69 normally is located behind the notched block 12 on the pulley 10 in position to prevent the weight 2,904,859 H which is attached thereto by the chain 13 from turning said pulley 19. The pin I4 on which said pulley 19 is mounted, the shaft 99 and the rod 99 are all mounted in portions of the bracket 15 attached to the rod 92. The rotative motion of the pulley 19 is transferred cases nrstca'rries the passage 99 in the upper half 42 ofthe-rotary valve connected to the head and turn the cam 19 thereof which in turn forces I the lever 19 (Fig. 5) upward against the rubber tube 49 squeezing it shut. The cam 19 is pivoted on 'the pin 99 between the front and back portions of the bracket II and is turned so that the roller 92 on the pin 93 carried thereby is brought against the-lever 19 and the thicker portion of said cam 19 is carried into position between pin 99 and said lever 19. The lever 19 is also located between front and back portions of the bracket BI but is pivoted on the pin 94. The pin 95 functions as a stop and limits the movement of the cam 19 in both directions. In this manner, the leaking head I5 is closed oil and the influx of air into the evacuating system is stopped.

Operation of the valve 55 is brought about through the shaft 95 on which the lever 19 is mounted which extends downwardly to the disc 91 which it engages through the pin 89; Before operation of the leak detecting mechanism, the

disc 91 is arranged so that groove 89 (Figs. 7,

- and disc 91 be turned, the groove 99 is also carried over the other aperture 92 in the bottom plate 9i and the source of vacuum connected thereto draws out the air in the system back to the closed stop cock 41. In this 'way, the manometer 59 is returned to its open circuit position in preparation for the resetting of the remainder of the leak detecting mechanism and the indexing of another head I5 into station B.

The resetting of the remainder of the leak detecting mechanism occurs before the next index and is brought about by rotation of the vcam 93 (Fig. 1) on the front cam shaft 94 in the lower portion of the frame 29. The cam shaft 94 is driven by the back main drive shaft 95 through the chain 96 and sprockets 91 and 98 indicated and .takes place in proper time relation to the other operations of the apparatus as the indexing. means (not shown) for the turret I1 is preferably operated thereby. The roller 99 engaged by the cam 93 in resetting the mechanism is positively connected to the operating shaft 96 of the lever 19 and the valve 55 through the lever I99, link IM and arm I92 and is only in position to be engaged when the mechanism requires resetting. The bracket I93 supporting the bottom plate 9I of the valve 55 and the pin I94 supporting the lever I99 are attached to the frame 29. The disc 81 is pressed tightly against the bottom plate 9I to prevent leakage by thespring I95 which butts against the collar I99 on the shaft 99. i

In the course of the next two succeeding index- Il over a passage (either I91 or I99) which admits a flushing gas to the head I5 and then causes it to come to rest over a passage (either I99 or II9) which is connected to the evacuating means (not shown). The passages I91 and I99 are connected in this instance to a supply of clean dry air, although nitrogen can be used equally as well for flushing if desired. The evacuating means connected to passages I99 and H9 is preferably the same as that connected to the head I5 at station 18.

. jects from the side of the tube 44 and is opened by a turning movement of the arm II3 (Fig. 1)

' which carries the roller 1 I4 against the cam III ing movements of the head I5 which advance said head into station D and then E, repeated flushing and exhausting operations are brought about providing the head I5 does not leak and pinch clamp 41 is not closed. The indexing in both of said pinch clamp Ill. The pinch clamp III corresponds in construction to the pinch clamp 41 adjacent which it is mounted and the arm II3 engages and turrys the cam II5 thereof so that the lever H9 is allowed to move down and the rubber tube II2 can return to full round condition. The arm I I3 is mounted on the upper end of the shaft I" supported by the frame 29 and is actuated by the following movement of the roller II9 on the arm I I9 on th lower end of said shaft II1 along the face of cam I29.

The cam I29 is mounted on the main drive shaft.

and the contracting force of the spring I2I which extends between a post in the frame 29 and the arm II3 causes the movement to occur as the cam I29 permits.

Should the head I5 entering station F be open to the atmosphere as indicated by a closed pinch clamp 41, thepin I22 on the outer end of the lever 19 thereof will be in a lower position than normal and will engage and push the roller I23, (Fig. 1) back out of position. The roller I23 isone part of the mechanism at this station which prevents the pinch clamp III from being opened and the exhaust system connected therefrom from being contaminated by the influx of air under these particular conditions. As shown in Fig. 1, the roller I23 is mounted on the lever I24 which is mounted on the plate I25 extending from theframe 29 and which is turned so that it engages the control pin I29 of thetotally inclosed switch I21. The lever I24 is normally turned by the contracting force of the spring I29 which extends between one end thereof and a post in the plate I25 so that the stop screw I29 engages the end of the switch I21 and when shifted causes said switch I21 to complete a circuit through the solenoid I39 -to the line. In

such cases. the armature of'the solenoid I39' which is connected to arm I32 by a link I3I turns the arm I32, the shaft I33 on which it is mounted and the arm I34 so that the latter is lowered into the path of movement of the arm II 3 and prevents it from moving far enough to open pinch clamp III. The spring I35 which butts against the arm I34 and bracket I35 is compressed during this operation and the expanding force thereof returns said arm I34 and the means connected thereto to their normal position when the head I5 is indexed from station F and the switch I21 is permitted to open again. The solenoid I39 and the shaft I33 are supported by the -bracket 4 L I36 which is attached --to theirame 20 at this 7 point.

Following the opening of the pinch clamp III under normal conditions of operation, the head I5 and the cups I6-/I6 carried thereby are drawn on by the second exhaust system. This system includes a mercury pump I31 (Figs. 1 and 2) for each head I5 which is connected to the rubber tube I I2 of the pinch clamp III by the pipe I38 and through the pipe I39 to the passage I40 in the upper half 42 or the rotary valve. The mercury pump I31 in general conforms to those shown in United States Patent 1,676,302 to van der Poel which issued July 10, 1928, and is backed up by other exhausting means (not shown) connected to the passage MI in thelower half 52 of the rotary valve.

The mercury pumps I31 are operated by the effect of the electrical heating unit I42 in the lower portion thereof which is enclosed in the insulated chamber I43 and the cooling effect of the water. in the tank I44 which is constantly being replenished from a source not shown and which overflows to the funnel I45 and pipe I46. The electrical current for the heating unit I42 is conducted thereto from the commutator I41 which comprises the brushes I48 on the insulating bracket I49 carried by the turret I1 and the metal rings I50 and I50 carried by the insulating collar I5I on the pipe I46. The rings I50 and I50 are engaged by the brushes I48 which are pressed thereagainst by springs (not shown) and are the stationary members of the commutator as the pipe I46 extends down through the hollow column I9 to the frame 20 and a drain for the cooling water. The electrical connections to the rings I50 and'l50' are made through wires (not shown) passing down'between the pipe I46 and the hollow column I9.

The exhausting operation of the second exhaust system is continuous during the operation of the apparatus and the control and connection of the system to heads I5 depends on the pinch clamp III. As shown in Fig. 6, a passage is provided in the lower half 52 of the rotary valve corresponding to passage I at each station taken by the head I5 except between stations A to E inclusive where the slot I52 is provided for connecting the mercury pumps I31 to another exhaust means so that they are kept in proper functioning order at all times.

The indexing movement of the head I5 from station F to G wipes the cam 18 of pinch clamp 41 on the stationary roller I53 causing it to turn and close off the exhaust line controlled thereby so that said head I5, from this time on, is drawn on only by the second exhaust system. The roller I53 is mounted on a yoke supported by the bracket I36.

No operation, other than the" exhausting of the head I5 by the second exhaust system, occurs during the movements thereof from stations G to J, but during the index from station J to K, the quality of the vacuum therein is tested by the apparatus shown diagrammatically in Fig. 9. The test apparatus is divided into three parts, the first of which comprises the resistances I54, I55, I56 and I51 which are mounted in pairs in the vitreous envelopes I58 and I59 and which are connected in a Wheatstone bridge circuit with the resistances in each envelope in diagonally opposite legs thereof. The envelope I59 is sealed except for the tube I60 which, in 'combination with the rubber tube I62 and pipe I63, connects it to the interior of the head I5 whereas the envelope I58 is preferably evacuated and sealed. Both envelopes I58 and I59 are mounted onthe turret l1 adjacent the 'head I5 so as to receive the same ambient temperature changes and are provided with coiled tungsten resistances like those used as filaments in incandescent lamps. The current is introduced in the bridge from the transformerI64 by the lead I65 connected to the resistances I55 and I 51 and the potentiometer I66 connected to the resistances I54 and I 56 which permits said bridge to be balanced. Once the bridge has been balanced with the head I5 properly evacuated, any improper condition of the vacuum causes heat to be conducted more rapidly from the resistances I56 and I51 to unbalance the bridge.

This unbalanced condition is not used except during the indexing movement of the head I5 from station J to K when the brushes I61 and I68 (Figs. 2, 3 and 9) which are mounted on the insulating block I69 at the periphery of the turret I1 and which are connected-to the ends of the opposite arms of the bridgecontact the separated metal bands I10 and "I on the stationary shoe I12. The shoe I12 is made of an insulating material and together with the vacuum tube amplifying means shown connected thereto forms the second part of the test apparatus. This means is mounted adjacent the-turret IT in a position not shown and amplifies the off-balance condition of the bridge so that it can cause the pinch clamp III andthe head I5 to be sealed from the second exhaust system if the vacuum is faulty. The amplifying means comprises the transformer I13, the primary which is connected to the inetal take-off bands I10 and HI and the secondary of which is connected to cathode I14 of the vacuum tube I15 and through the condenser I16 and the resistance I11 to a grid thereof. The other parts of the amplifier comprise the transformer I18 which is connected to the line and to the cathode heating filament and which has a center tap on the primary connected to said cathode I14, the condenser I19 which is connected across the secondary of transformer I13, the milliammeter I which is connected to the plate of the vacuum tube I15 and the actuating coil of the relay I8I and the condenser I82 and resistance I83 connected between the leads from said coil. The plateuand third grid of the vacuum tube I15 are placed at the proper potential by the lead I84 from one side of the line which is connected to the plate through the coil-of the relay I8I and directly to the third grid. The function of the parts of the amplifying means is believed to be apparent Therelay I8I controls the operation of the third part of the test apparatus in that it completes the line circuit to the solenoid I85 (Figs.

1 and 9) which indirectly raises the roller I86 so that the cam II5 of pinch clamp III strikes it during the indexing motion and takes the closed position. The armature I 81. of the solenoid I85 is connected to the arm I88 on the shaft I89 by the link I90 and when actuated turns said shaftI89 so that arm, I9I andlink I92 are moved into alignment with each other and lever I93 carrying the roller I86 is raised. The lever ,ese 5 I is pivoted on tlie pin I84 held by the bracket which also holds the u er end f th 3 I95 extending from the frame 29 which also sup- .224. pp s o 8 8pm,

ports the shaft I89. Since the test apparatus only closes the pinch clamp III when a faulty head I5 is indexed into position, the second exhaust system will normally continue to draw on raised in temperature under normal conditions.

The supporting rods 28 for the heater in each case are connected by wires to the studs I96 (Figs. 1 and 2) extending the insulating block I91 on the turret I'I below each head I5 and the electrical connections are made thereto at each of the four stations by means engaging separate an ular contact surfaces of the blocks I98 on the lower ends thereof. At station K, as shown in Fi'gs. 1 and 10, the contacts I99 are carried into engagement with the blocks I98 by movement of the levers 299 and the arm 29I on which they are mounted I and connect the secondary of the transformer 292 shown diagrammatically in Fig. 11 thereto. The contacts I9 9 are insulated by suitable washers and sleeves from the levers 299 which are pivotally mounted on the pin 293 carried by the arm '29I and which turn on said pin 293 against the contracting force of the springs 294 to absorb the excess movement of arm 29!. Each spring 294 extends from a post in a projecting portion of the arm 29I and through a passage therein to the lowermost part of the lever 299 whose position prior to the engagement of the contacts is established by the stop screw 295. The arm 29I is mounted on a shaft 296 supported by the bracket 291 extending from the frame 29 and is actuated from the shaft 298 which is similarly supported by the bracket 299 and which is actuated by the engagement of the roller 2I9 on the lever 2I I with the cam 2I2 on the main drive shaft 95. The motion of shaft 298 is transferredto shaft 296 through the arms 2I3 and 2 on respective shafts which are Joined by the link 2I5.' At station L, levers 2I6 and the arm 2II which is mounted on the shaft 298 perform the same function as levers 299 and arm 29I respectively, while at station M, levers 2I8 and lever 2II perform these functions. At station N, levers not shown corresponding to levers 2I8 and an arm only partially shown at 2I I corresponding to the upper part of lever 2H carry the contacts I99 into engagement with the blocks I98 and'the head I5.

At each of these stations K, L, M and N, electrical current does not pass through the heater operated in pairs by the cams 222 and 222 on a portion of the cam shaft 94 extending to the right farther than shown in Fig. 1 and are turned about the pin 223by the contracting force of the springs 224 under the direction of the following movement of the rollers 225 on the forward end of levers 22I which engage said cams 222 and 222. The pin 223 is carried by the bracket 226 which is attached to an adjacent part of the frame 29 switch229 is tipped.

The switches 2 I9 which are in the line leads to the transformer 292 are, as shown in Fig. 1, of totally enclosed form and are mounted on the frame 29 in position to be operated by the pinch clamp II I when the head I5 takes positions K. L, M and N. If the head I! is not evacuated to the degree desired, pinch clamp II I will have been closed on reaching these positions and the pin 22'! extending from the lever 8 thereof will be lower than normal and will displace the levers 228 and operate the switches 2I9. Normally. each switch 2I9 is closed and the lever 228 is turned about the pin 229 by the contracting force of the spring 239 to the limit allowed by the stop screw 23I but when the pin 22! is down it engages the roller 232 on the end of said lever 228 and swings it against the control pin 233 of said switch 2I9.- This operation opens the switch 2I9 and prevents the circuit from being closed when the mercury At station K, the heater is not raised to a. temperature high enough to vaporize the metal body 22 held by the coils but only to about 600 C. so as to drive, oil the moisture and dissipate any other type of contamination which can be carried off by the exhaust system. The control of this temperature is afforded by the rheostat 234 in the primary circuit to the transformer 292. At the succeeding stations L, M and N, the heaters 23 are raised to about 2000 C. and in some instances even to a higher temperature so as to heat the bodies 22 of metal in the coils 23' thereof and cause them to be vaporized. The vaporizing of the metal takes place very rapidly and in most instances is completely brought about before the head 'I5 enters the last flashing station. As the heater coils 23'-23' are at approximately the centers of the cups I5- I8, the vaporized metal condenses on the interior thereof in a relatively uniform deposit which forms a very efllcient light reflecting coating. The proper distribution of the metal over the interior of the cups I8 is assisted'by the baflies or partitions 235-235 which 3 apparently prevent the metal vaporized by one heater coil from depositing on the cup on the opposite side of the'head I5 and assist in the proper withdrawing of the atmosphere and impurities from the space adjacent the rim of the cups I8I6. The baffles 235235 whlchar'e the subject matter of a separate application of Carl Lenz Serial No. 318,963 filed February 14, 1940, engage the gaskets 38-38 and the body 25 of the head I 5 and are held in place by the spring clip 235.

Following the last flashing operation and the indexing movement of the head I5 from station N, the cam II5 of pinch clamp III moves against the stationary roller 231 (Fig. l) and said pinch clamp III is closed. The roller 231 is held by a yoke carried by the bracket-238 extending from the frame 29. By closing off the pinch clamp I I I,

the second exhaust system is permanently stopped from drawing on the head I5 at any further time in this cycle of operation of the apparatus.

Station 0 is an idle station and it is not until the head I5 is indexed into station P that the next and final operation of the apparatus takes place. At station P, the pinch clamp 41 is opened by movement of the roller 239 on the lever 249 against the cam 18 thereof which is shifted so that the dry air connected thereto through the rotary valve is allowed to enter the head I5 and the cups Iii-I6. The lever 249 is pivoted on a pin projecting from the, frame 29 and is actuated by the interconnected arms 2 and 242, the lat- 1 ter of which engages said lever 240 through the link 243 and the former of which is connected to the lever 244 by the rod 245. 'The lever 244 is pivoted on a pin extending from the frame and is operated by the face or box cam 246 on the'cam shaft 94 which it engages through the roller 241. The dry air is conducted through the pinch clamp 41 at this time since the passage 50 in the upper half 42 of the rotary valve is now aligned with the passage 248 (Fig. 6) in the lower half 52 thereof which is connected to the source of supply of said air (not shown) The entrance of the dry air into the cups Hi -l 6 allows them to be easily removed at station Q by the operator after the holders 36 and 36 have been moved back.

What I claim as new and desire to secure b Letters Patent of the United States is:

1. Apparatus for depositing a reflecting coating on the inner surfaces of a pair of cup-shaped bodies comprising a hollow head member having side portions each shaped to engag and form an air-tight seal with the edges of said cup-shaped bodies and having a connecting passage Ior permitting the space enclosed by said bodies to be exhausted, and electric heater coils mounted within said head and projecting into the space enclosed by said bodies along the axis through said head and bodies, and means for heating said coils to vaporize bodies of th coating material placed located in said opening, a carrier for advancing therein so that the vapor condenses on the inner base member is placed and a connecting passage for permitting said opening and the space enclosed by said basemember'to be exhausted, electrical heating means mounted on the head in the opening therein and arranged to carry a quantity of vaporizable coating'material, means for connecting said heating means to a source of current to preliminarily heat it to a degree insuflicient to vaporize said coating material but suflicient to expel contaminating substances from the heating means and from the coating material associated therewith, said contaminating substances being withdrawn through said connecting passage, and means for subsequently causing said heating means to be heated sufficiently to vaporize the coating material so that it condenses on the surface of said base member.

3. Apparatus for depositing a reflecting coating on the surface of a base member comprising a head having an opening therein over which said base member is placed, electrical heating means located in said openin a carrier for advancing the head to a plurality of stations in turn, an exhausting means, means at at least one of said stations for connecting the opening in said head and the space enclosed by said base member to said exhausting means, a second exhausting means mounted on the carrienmeans for .eonnecting said second exhaust means to said head at a following station, and means, operable upon movement of said carrier, for i connecting the heating means of said head to a source of current at another station for vaporizing a body.of the coating material associated therewith so that it condenses on the surface of said base member.

4. Apparatus for depositing a reflecting coating on the surface of a base member comprising a head having an opening therein over which said base member is placed, electrical heating means thehead toia plurality of stations in turn, means controlled by the movements of the carrier and connected to the opening in said head for causing a preliminary exhausting, a flushing and then a more: complete exhausting of said opening and the space enclosed by said base member, and means, operable upon movement of said carrier, for connecting the heating means of said head to a source of current at another station for vaporizing a body of the coating material associated therewith so that it condenses on the surface of said base member.

5. Apparatus for depositing a reflecting coating on the surface of a base member comprising a head having an opening therein over which the base member is placed, electrical heating means located in said opening, a carrier for advancing the head to a plurality of stations in turn, an exhaust means, means including a valve mounted on the carrier for connecting the opening in said head and the space enclosed by said base member tosaid exhaust means, means located along the .path of movement of the carrier for opening and closing said valve at different points along said path, a second exhausting means mounted on said carrier, means including a second valve for connect ing said head and said second exhausting means together, means located further along the path of movement of the carrier for opening and closing the said second valve in order at different points along said path, and means, operable upon movement of said carrier, for connectingsaid heating means to a source of current at another station for vaporizing a body of the coating material associated therewith so that it condenses on the surface of said base member. I a

6. Apparatus for depositing a reflecting coat-' ing on the surface of a base member comprising a head having an openin therein over which the base member is placed electrical heating means located in said opening, a carrier for advancing the head to a plurality of stations in turn, an exhausting means, means at a plurality of said stations for connecting the opening in said head and the space enclosed by said base member to said exhausting means, means for connecting said heating means to a source of current at another station for vaporizing abody of the coating material associated therewith so that it condenses on the surfaces of said base member, means at one of said exhausting stations for testing the quality of the vacuum held by the head and for closing off the connection thereto when unsatisfactory vacuum is indicated, and means, operable upon the closing ofi' of said vacuum connection, for preventing the completion of -the electrical circuit to the said heating means. v i

7. Apparatus for depositing a reflecting coating on the surface of a base member comprising,

a head having an opening therein over which the base member is placed, electrical heating means located in said opening, a carrier for advancing the head to a plurality of stations in turn an exhausting means, means at a plurality of said testing the quality of the vacuum held by the head and for closing oil the vacuum connection thereto when unsatisfactory vacuum is indicated, a displaceable member mounted on the carrier and arranged to be repositioned by the closing off of said vacuum connection, a normally closed switch located at the same station as the said electrical connection-making means and connected in the circuit thereto, and means mounted adjacent the said switch and engaged by said displaceable member when it is repositioned for opening the said switch and preventing the completion of the electrical circuit to the said heating means.

8. Apparatus for depositing a reflecting coating on the interior surfaces of a plurality of cupshaped bodies comprising a rotatable turret, a plurality of heads mounted at the periphery of the turret, each of said heads having an opening therein over which one of said bodies is placed and electrical heating means located in said opening, means connected to said openings in the heads and the spaces enclosed by said bodies for permitting the exhausting thereof during the rotation of the turret, and means located adjacent the periphery of the turret for connecting the heatin means of a plurality of heads in turn to a source of current, upon rotation' of said turret to vaporize a body of the coating material associated therewith so that it condenses on the inner surfaces of said cup-shaped bodies.

9. In a device of the class described, a hollow head member having side portions shaped to engage and form an air-tight seal with the edges of a plurality of bodies held thereagainst in opposed relationship whereby the said hollow head member and said bodies conjointly form an airtight enclosure, an exhaust connection to said head member, means carried by said head member within said enclosure for supporting a quantity of vaporizable coating material, and means for heating said last-mentioned means to vaporize said coating material so that it condenses on the surfaces of said bodies.

10. In a device of the class described, a hollow head member having side portions shaped to engage and form an air-tight seal with the edges of a pair of bodies held thereagainst in opposed relationship whereby the said hollow head member and said bodies conjointly form an air-tight enclosure, an exhaust connection to said head member, means carried by said head member within said enclosure for supporting a quantity of vaporizable coating material adjacent each of said bodies, and means for heating said lastmentioned means to vaporize said coating material so that it condenses on the surfaces of both of said bodies.

11. In a device of the class described, a head comprising a hollow ring-shaped portion having its opposite sides shaped to engage and form an air-tight seal with the edges of a pair of bodies held thereagainst in opposed relationship whereby the said ring-shaped portion and said bodies conjointly form an air-tight enclosure, an exhaust connection to said ring-shaped head portion, means carried by said ring-shaped head portion within said enclosure for supporting a quantity of vaporizable coating material, and means for heating said last-mentioned means to vaporize said coating material so that it condenses on the surfaces of both of said bodies.

12 In a device of the class described, a head comprising a hollow ring-shaped portion having its opposite sides shaped to engage and form an air-tight seal with the edges of a pair of bodies held thereagainst in opposed relationship whereby the said ring-shaped portion and said bodies conjointly form. an air-tight enclosure, an exhaust connection to said ring-shaped head portion, conductive support members extending into the interior of said ring-shaped portions from opposite sides thereof and transversely of the axis thereof, and an electrical heater element within said ring-shaped head portion supported at its ends by, and electrically connected to, said support members, said heater element being constructed and arranged to support and vaporize a quantity of vaporizable coating material so that it condenses on the surfaces of both of said bodies.

13. In a device of the class described, a head comprising a hollow ring-shaped portion having its opposite sides shaped to engage and form an air-tight seal with the edges of a, pair of bodies held thereagainst in opposed relationship whereby the said ring-shaped portion and said bodies conjointly form an air-tight enclosure, an exhaust connection to said ring-shaped head portion, conductive support members extending into the interior of said ring-shaped portion from 0pposite sides thereof and transversely of the axis thereof, and an electrical heater element within said ring-shaped head portion supported at its ends by, and electrically connected to, said support members, said heater element comprising intermediate portions extending substantially axially of said ring-shaped head portion and beyond the said sides thereof, said intermediate heater portions being constructed and arranged to support and vaporize a quantity of vaporizable coating material adjacent each of said bodies to thereby coat both of said bodies.

ROYAL F. STRICKLAND. FRANK J. MALLOY. GERALD W. POVALL.

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