US2843428A - Withdrawing masking material from bulbs - Google Patents

Description

4 Sheets-Sheet 2' M Y 4 w W%% h 4 w M y 7 a 4 a a2 a w C. RVEDGERLY ETAL July .15, 1958 I WITHDRAWING MASKING MATERIAL FROM BULBS Filed May 20, 1954 q fl F c 4 v 9 i W 2 9 w 7 7. WI 5 Q a n J 2 i "J 1 v 3 2 LL a w 7 E L? July 15, 1958 CR. EDGERLY ETAL 2,343,428

WITHDRAWING MASKING MATERIAL FROM BULBS Filed May 20, 1954 4 Sheets-Sheet 3 51 J2, JZ 50 4s A 49 u 1 55 46 a4 July 15, 1958 C.- R. EDGERLY ETAL WITHDRAWING MASKING MATERIAL FROM BULBS 4 Sheets-Sheet 4 Filed May 20, 1954 IN VEN TORJ' Y m E v a United States Patent WITHDRAWING MASKING MATERIAL FROM BULBS Charles R. Edgerly, Bloomfield, N. J., and Robert M. Brady, New York, N. Y., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 20, 1954, Serial No. 431,048

6 Claims. (Cl. 302-17) This invention relates to coating the interior surfaces of translucent vitreous envelopes with specular material, preferably metal such as silver or aluminum.

An object of our invention, generally considered, is to manufacture bulbs for heat, spot, flood and sun lamps, as well as for other devices in which radiant energy is to be reflected therefrom in a certain direction, by applying a specular coating of a metal, particularly silver, as an 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 our 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 our invention is to provide a machine for automatically adjusting the masking material in the bulb, evacuating, flashing specular material on the unmasked portion of the bulb, removing the coated bulb from the machine, and transferring the masking material to another bulb to be coated.

An additional object of our invention is to provide semi-automatic means for withdrawing the granular masking material from each bulb and transferring it to another bulb to be coated, as an improvement over the means disclosed in the May and Edger ly application, Ser. No. 348,044, filed April 10, 1953, now Patent 2,811,394 and owned by the assignee of the present application.

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

In the drawings:

Fig. 1 is an elevational view of apparatus for withdrawing granular masking material from a bulb which has been coated and transferring it to a bulb to be coated.

Figs. 2, 3 and 4 are horizontal sectional views on the correspondingly numbered lines of Fig. 1 in the direction of the arrows.

Fig. 5 is an elevational view, with parts in vertical section on the line V-V of Fig. l, in the direction of the arrows.

Fig. 6 is a view corresponding to a part of Fig. l at the left side, to a larger scale, with the bulb to be filled elevated, and with parts in vertical section and taken on the line VI-VI of Fig. 4.

Fig. 7 is an elevational view, with parts in section on the line VII-VIl of Fig. l, in the direction of the arrows and to the scale of Fig. 5.

Fig. 8 is an axial sectional view of the bulb to be emptied, prior to reaching the position of Fig. l, but to a larger scale.

Fig. 9 is an axial sectionalview of the bulb .to be emptied, as it appearsat the right of Fig. .1, butto the scale of Fig. 8. i

2,843,428 Patented July 15, 1958 Figs. 10 and 11 are horizontal sectional views on the correspondingly numbered lines of Figs. 8 and 9, respectively, in the direction of the arrows.

Fig. 12 is a wiring diagram.

The Green Patent No. 2,569,852, dated October 2, 1951 discloses and claims apparatus which is very satisfactory for the manufacture of reflecting bulbs for devices, such as infrared lamps and sun lamps, provided the specular material applied to such bulbs is a relatively durable metal such as aluminum. However, when it is desired to substitute a softer metal, such as silver, for such aluminum there is danger of the granular masking material, which may be glass beads, scratching the coating and creating a poor product, if the unloading mechanism disclosed in said patent is employed.

In other words, the reversing of the bulbs after coating, from a position in which the necks extend upwardly to one in which they extend downwardly, results in the granular masking material rubbing the specular coating, thereby running the risk of damage thereto unless said coating is relatively durable. In accordance with our invention, we propose to substitute a suction withdrawal of such masking material from the bulbs after coating, for that by reversal in position, thereby preventing the masking material from abrasively engaging the coating material in order to avoid damage thereto.

In practicing our improved process, and referring to the drawing in detail, like parts being denoted by like reference characters, we first take an open neck glass bulb or envelope 12, and invert it. A measured quantity of granular masking material 18 (see Fig. 8), preferably fine glass granules, but which may be Alundum powder or other heavy, fine, preferably non-metallic power of granular material, is then poured therein as from a receptacle or other bulb. The granular material 18 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. This granular material may be evenly distributed in the bowl portion of the bulb in any desired manner, preferably by twirling as disclosed in the Green patent referred to.

After being so distributed, the bulb is placed in a coating machine which may be generally of the type described and claimed in said Green patent, previously referred to.

Such a machine, as diagrammatically shown in Fig. 7 of this patent, is substantially a well-known type of exhaust machine having the customary rotating index head and hence a detailed description thereof is deemed superfluous. Suflice it to say that at one of its index positions an operator loads the machine with the masked bulbs which are first given a preliminary exhaust at several indexed positions of the machine, followed by a final exhaust at additional indexed positions and thereafter at a further indexed position a metal is flashed to apply a specular coating to the unmasked portions of the bulb.

The only difference between the flashing operation in the present instance and that of the patent referred to, is that silver is preferably employed rather than aluminum, and the flashing filament is desirably formed of flattened tantalum wire rather than tungsten wire, as such wire has been found to Work better with silver than tungsten wire.

After flashing has been completed, the bulb is removed at a further indexed position of the rotating machine head and placed on a vertically movable first bulb support or platform 19, Figs. 1, 7 and 8, desirably formed of Bakelite or similar material which, in turn, rests on a guiding bracket 21. The bracket 21 carries an angle iron 28 formed with a rearwardly opening notch ,29 receivinga asaaszs guiding rod 30. The ends of the rod 30 are respectively secured to horizontal structural members 31 and 32 of a supporting frame 33 projecting upwardly from the table 25. The support 19 has an aperture 22 therein through which the central portion of the bowl 17 of the bulb may be seen. The neck of the bulb is supported between a pair of springs 20, extending from the bracket 21, in turn carried by the piston rod 23 extending upward from a piston 40 (Fig. 12) in an air cylinder 24 carried beneath the supporting table 25. A suitable electrically-controlled valve 26 (Fig. 12) is provided to cause the piston and its rod 23 to move up or down, as desired.

' We provide a fixed vacuum suction tube 27 for withdrawing the masking material 18 from the interior of each bulb 12, after coating on the aforementioned indexing machine. The upper end portion of the suction tube 27 extends horizontally, as indicated at 34, and unites with a tank or hopper 35. The horizontal portion 34 of said tube is desirably connected with the vertical portion 27 by means of a rubber elbow 36. The purpose of this connection is to avoid the quick wearing out of the elbow portion, which occurs if of metal due to abrasive. action of the glass beads.

The hopper or tank 35 is in turn connected to a vacuum pump, or other source of vacuum, by means of a suitable pipe or vacuum line 37. The connection to said source is controlled by a normally-closed solenoid-controlled valve 38, operated from a source of power in accordance with the wiring diagram of Fig. 12. The electric current to the solenoid of said valve 38 is, in turn, controlled by a switch 39 closed and opened, respectively, by upward and downward movement of the cam 41 which is secured to the reciprocating support 19. Said cam 41 acts on a roller 42 on the end of a lever 43, pivoted to the housing of the switch 39 and acting to close the switch 39 upon counter-clockwise rotation, as viewed in Fig. 1.

The inner end of the pipe 34, discharging into the hopper 35, is provided with a flaring terminal portion 44, in turn surrounded by a restricting skirt portion 45, connected to the inner surface of the hopper 35, as viewed in Fig. 5. Above the skirt portion 45 is another similar but shorter skirt portion 46, encircling a baffie member 47 of generallyconical shape. The latter is held in place by supporting legs 48, the ends of which are flanged as indicated at 49, and respectively secured to the bafile 47 and the interior surface of the hopper 35.

The upper end of the hopper is partially closed by an annular header member, in the form of a flat ring (not shown) and held in place, as by screws 50. There is secured to said header member, as by means of bolts carrying thumb nuts 51, a frusto-conical connecting tube 52. The upper end of the tube 52 is threadably connected to the lower end of the pipe 37.

Tightness of connection is desirably insured by gasket means 53. Disposed within the tube 52, and the base or lower portion of which is held between the base of the tube 52 and the member 51, is a generally conical metal screen of fine mesh (not shown), to prevent undesired withdrawal of particles of masking material from the hopper into the vacuum line. The lower end of the hopper 35 is generally hollow, frusto-conical, and terminates in a discharge pipe 54, the lower end of which is beveled, as shown most clearly in Fig. 5 and provided with a normally-spring-closed gate valve 55.

The details of this valve 55 are shown enlarged in Fig. 3, the closing spring being indicated at 56. The valve is pivoted as indicated at 57, the pivot serving as a holder for the spring 56 which torsionally acts to hold it in closed position. Opening of the valve is efiected by means of a solenoid 58, the armature 59 of which is connected to said valve by means of a link 61.

Disposed beneath the discharge pipe 54 is a receiving funnel 62 terminating in a discharge pipe 63. Said pipe is provided with a constricting bushing 64 which serves to check the velocity of the beads as they flow through the pipe 63, as well as controlling the flow thereof to the desired extent.

Directly beneath the lower end of the pipe 63 is a vertically movable second bulb support or platform 65, similar to the first support 19, or that on the right side of the machine as viewed in Fig. 1. This support is also desirably formed of Bakelite or similar material, and in turn rests on a guiding bracket 66. The bracket 66 carries an angle iron 67, formed with a rearwardly opening notch 68 receiving a guiding rod 69. The ends of the rod 69 are respectively secured to horizontal structural members 71 and 72 of the supporting frame 33.

The support has an aperture 73 therein through which the central portion of the bowl 17 of the bulb 12 may be seen. The neck of the bulb is supported between a pair of springs 7 4, like the springs 20, extending from the bracket 66, in turn carried by the piston rod 75. The latter extends upward from a piston 7 0 (Fig. 12) in an air cylinder 76 carried beneath the supporting table 25. A suitably electrically controlled valve 77 is provided to cause the piston and its rod to move up or down as desired.

In addition to the previously-mentioned cam-controlled switches operated as the piston rods move up and down, we have a switch 78, closed upon upward movement of the piston rod 75 and its bulb support 65, and a switch 79 closed upon downward movement of the piston rod 23 and its support 19. These switches, 78 and 79, are similar in construction to the switch 39, except that the switch 79 is reversed in position. The switches 78 and 79, as will be seen from Fig. 12, are in series so that both must be closed in order to allow the solenoid 58 to be energized from the source of power 81 to open the bead gate valve 55.

The primary winding 82 of a step-down transformer 83 is also energized from said source of power 81, so that the secondary winding 84 serves to energize the solenoids 85, 86, 87 and 88, which respectively control the air valves 77 and 26. These solenoids are controlled by up push-button or control switch 89 and down push-button or control switch 91, the up signifying that pushing of this button moves the support 19 up while simultaneously drawing the support 65 down, the down signifying that pushing thereof causes the support 19 to move down while simultaneously causing the support 65 to move up.

The lower end of the suction tube 27 carries a centralizer and air baflies consisting of the following parts. A centralizer weight 92 is slidably mounted on the suction tube 27 and formed with a series of apertures 93 to allow a regulated supply of air to be drawn to the bulb 12 at exhaust, so that the granular material or beads 18 may be withdrawn quickly and smoothly. The weight of this parttends to hold the bulb 12 more firmly on its support 19.

This centralizer weight 92 not only has these apertures 93 but also a series of screw holes 94, serving to receive screws 95 (Fig. 11) which hold a tapered lower part 96 thereon. This tapered part 96 acts to centralize the tube 27 with respect to a bulb 12, since it conforms to the taper at the top of the bulb neck. It is desirably made of micarta, or other similar material, to prevent bulb breakage. It has grooves 97, aligned with the apertures 93 in the part 92, and is correspondingly apertured and threaded for receiving the connecting screws 95.

In the present instance, the exhaust tube air baflle is formed in two parts. A lower baflie part 98 acts as an inverted funnel fixed to the tube 27, as by means of a set screw 99. An upper baflle part 101 is adjusted in position and then fixed to the tube 27 as by means of a set screw 102. In other words, it may be shifted vertically along the exhaust tube 26 to regulate the quantity and velocity of the air entering the bulb to remove the beads.

The parts of the mechanism are so constructed, supported and controlled in movement that as the support 19 moves upward the support 65 moves downward. A bulb 12 carried by said support 19 does not meet the lower end of the baflie part 98, but approaches it quite closely or to the position as viewed in Fig. 9. As this support 19 moves upward, the neck of a positioned bulb 12 engages the centralizer 96, causing relative movement thereof along the tube 27 from the position of Fig. 8 to that of Fig. 9. This centralizer portion serves to insure that neither the baffle 98 nor the bafile 101 will scratch the reflecting coating 16, as said centralizing action is efiective prior to the baifie member 98 reaching the upper terminal line 104 of said coating.

Operation The operation of transferring masking material or beads from bulbs which have been silvered, to bulbs which are to be silvered, may be started when the suction piston 40, from which the rod 23 projects, in the down position, while the filling piston 70, from which the rod 75, projects is in the up position. This means that the operation may be started after the down button 91 has been pushed, to admit air above the piston 40 and below the piston 70, so that the parts are as shown in Fig. 12. If the apparatus has previously been operated, an empty bulb 12 is then removed from the platform 19 and replaced by a silvered bulb 12 containing beads to be removed and transported to a bulb 12 on the platform 65. However, no bulb can be applied to the platform 65 while it is in the up position.

In the position illustrated in Fig. 12, it will be seen that the switch 39 is open, thereby insuring that the solenoid of the valve 38 is deenergized and its vacuum valve closed. The switch 78, however, is closed as well as the switch 79, so that the bead gate valve 55 is held open. Any beads in the hopper 35 would have been discharged into an empty bulb, if positioned on support 65.

The operation may be begun by pushing the up button 89, energizing the up solenoid 87 of the suction piston 40, and the clown solenoid 85 of the filling piston 70, to effect corresponding movement of bulbs on the pistonoperated platforms 1'9 and 65, to the positions illustrated in Fig. 1.

As the platform of the suction piston 40 moves up a bulb 12 to be emptied, said bulb receives the suction tube 27, the centralizer 96, centralizer weight 92, and the bafiles 93 and 101. At the same time the support 65 on descending moves an empty bulb down. away from the filling funnel 62 as it receives beads therefrom, if the machine had previously been operated. However, if this is the beginning of an operation on the machine, it merely withdraws the support 65 to the down position, so that an empty bulb can be placed thereon for filling at the next filling operation. Upon such movement, the switches 78 and 79 are simultaneously opened, releasing the bead gate solenoid 58, and allowing the gate valve 55 to be spring-closed to make the hopper 35 air-tight.

When the support 19 reaches the upper limit of its travel, the switch 39 is closed, opening solenoid valve 38, thereby causing vacuum to draw the beads from the bulb 12 on the suction platform 19 into the hopper or tank 35. By virtue of the specially formed baffles 98 and 101, adjusted to position on the tube -27, and held by means of setserews 99 and 102 the currents of air which pass through the apertures 93 and the neck of the bulb 12 and along said tube are particularly effective for carrying all of the masking material 18, from the bulb to be emptied, into the suction tube'27, from whence it is deposited inthe hopper 35. .An empty bulb is then placed on thefillirig support 65, or a filled bulb thereon replaced by an empty bulb, said support being then in down position.

When the "bulb 12has been completely emptied, this garages being determined by the operator viewing the bottom thereof, the operator then pushes the down button 91, energizing the down solenoid 88 of the suction piston 40 and the up solenoid 86 of the filling piston 70 to effect corresponding movement of the bulbs on the supports. This movement causes opening of the switch 39, cutting 01f the vacuum to the hopper 35, and closing of the switches 78 and 79, thereby energizing the bead gate solenoid 58 and opening the gate valve 55 to discharge beads to the funnel 62 and from there to the empty bulb 12 therebeneath. The emptied bulb on the suction support 19 is then replaced by a full silvered bulb for a repetition of the operation.

From the foregoing description, it will be seen that we have provided apparatus which is practically automatic in that upon loading and unloading bulbs from the appropriate vertically-movable supports, the operation is effected by the mere alternate pushing of up and down buttons of electric control switches. though a preferred embodiment has been disclosed, it will be understood that modifications may be made within the spirit and scope of the invention.

We claim:

1. Mechanism for unloading bulbs which contain granular masking material after removal from a machine which has processed them by the application of specular coatings to unmasked portions of their interior surfaces, comprising a suction tube, a first bulb support mounted for vertical reciprocation therebeneath to raise a processed loaded bulb to receive said tube for the withdrawal therefrom of masking material, a vacuum line, a hopper at which said line terminates, a solenoid-controlled valve in said line, a switch in the circuit of said valve, closed by movement of said support to up position for opening said valve to evacuate said hopper, a solenoidcontrolled gate valve at the outlet from said hopper, normally spring-closed to permit evacuation and prevent said hopper from discharging any contained masking material, a second bulb support mounted for vertical reciprocation beneath said hopper, means operable to automatically cause the simultaneous vertical reciprocation of both said bulb supports in a direction opposite to each other, means connecting said suction tube to said hopper for the discharge of masking material thereinto from a raised bulb on said first support, and switches in the circuit to the solenoid of said gate valve, and respectively closed upon the automatic simultaneous movement of the first bulb support, to its down position and the second bulb support to its up position, for opening said gate valve to discharge any masking material from said hopper into an empty bulb on said second support, in order to arrange for first the flow of masking material from a processed bulb on said first support into said hopper and, thereafter, allow material to flow from said hopper into an empty bulb therebeneath.

2. Mechanism for unloading bulbs which contain granular masking material after removal from a machine which has applied specular coatings to unmasked portions of their interior surfaces, comprising a suction tube, a first bulb support mounted for vertical reciprocation for supporting a loaded bulb open neck upward therebeneath, a vacuum line, a hopper at which said line terminates, a solenoid-controlled valve in said line, a switch closed by movement of said support to up position for energizing the solenoid of said valve to connect said line to said hopper, a gate valve normally preventing said hopper from discharging its contents, a second bulb support mounted for vertical reciprocation for supporting an empty bulb open'ncci; upward beneath said hopper, means operable to automatically cause the simultaneous vertical reciporation of both said bulb'supports in a direction opposite to each other, means connecting said suction tube tosaid hopper for the discharge of masking material thereinto from a loaded bulb on said firstmentionedsupport, andqa solenoid controlling the discharge from said hopper into an empty bulb on said second bulb support and operable by the vertical reciprocal movement of the latter, in order to arrange for first the flow of material from a processed bulb into said hopper and, thereafter, allow material to flow from said hopper into an empty bulb therebeneath.

3. Mechanism for unloading bulbs which contain granular masking material after removing from a machine which has applied specular coatings to unmasked portions of their interior surfaces, comprising a suction tube, a first bulb support, an air-operated piston and rod, on the top of which said support is mounted for vertical reciprocation for supporting a loaded bulb open neck upward beneath said tube, a vacuum line, a hopper at which said line terminates, a solenoid-controlled valve in said line, a switch closed by movement of said support to up position for energizing the solenoid of said valve to connect said line to said hopper, a gate valve normally preventing said hopper from discharging its contents, a second bulb support, an air-operated piston and nod, on the top of which said support is mounted for vertical reciprocation for supporting an empty bulb open neck upward beneath said hopper, means connecting said suction tube to said hopper for the discharge of masking material thereinto from a loaded bulb on said first-mentioned support, a solenoid-controlling the discharge from said hopper into an empty bulb on said second support, and a push-button-operated circuit controlling the simultaneous opposite operation of said pistons so that one piston always moves down as the other moves up and vice versa, in order to first arrange for the flow of material from a processed bulb into said hopper and, thereafter, allow material to flow from said hopper into an empty bulb therebeneath.

4. Mechanism for unloading bulbs which contain granular masking material after removal from a machine which has processed them by the application of specular coatings to unmasked portions of their interior surfaces, comprising a suction tube, a first bulb support, an airoperated piston and rod on the top of which said support is mounted for vertical reciprocation to raise a processed loaded bulb to receive said tube for the withdrawal therefrom of masking material, a vacuum line, a hopper at which said line terminates, a solenoid-controlled valve in said line, a switch in the circuit to said valve, closed by movement of said support to up position for opening said valve to evacuate said hopper, a solenoid-controlled gate valve at the outlet from said hopper normally spring-closed to permit evacuation and prevent said hopper from discharging any contained masking material, a second bulb support, an air-operated piston and rod on the top of which said support is mounted for vertical reciprocation beneath said hopper, means connecting said suction tube to said hopper for the discharge of masking material thereinto from a raised bulb on said first support, and switches in the circuit to the solenoid of said gate valve, and respectively closed upon the automatic movement of the first bulb support to its down position and the simultaneous automatic movement of said second bulb support to its up position for opening said gate valve to discharge any masking material from said hopper into an empty bulb on said second support. a

5. Mechanism for unloading bulbs which contain granular masking material after removal from a machine which has processed them by the application of specular coatings to unmasked portions of their interior surfaces, comprising a suction tube, a first bulb support, an electrically operated air-driven piston and rod on the top of which said support is mounted for vertical reciprocation to raise a processed bulb to receive said suction tube for the withdrawal therefrom of masking material, a.

vacuum line, a hopper at which said line terminates, a solenoid-controlled valve in said line, a switch in the circuit to said valve, closed by movement of said support to up position for opening said valve to evacuate said hopper, a solenoid-controlled gate valve at the outlet from said hopper normally spring-closed to permit evacuation and prevent said hopper from discharging any contained masking material, a second bulb support, an electrically operated air-driven piston and rod on the top of which said support is mounted for vertical reciprocation beneath said hopper, means connecting said suction tube to said hopper for the discharge of masking material thereinto from a raised bulb on said first support, switches in the circuit to the solenoid of said gate valve, and respectively closed upon the simultaneous automatic movement of the first bulb support to its down position and the second bulb support to its up position for opening said gate valve to discharge any masking material from said hopper into an empty bulb on said second support, and up and down push button operated switches in the circuit controlling the operation of said pistons in order to provide for the simultaneous travel of said pistons in opposite directions to arrange for first the flow of masking material from a processed bulb on said first support into said hopper and, thereafter, allow material to flow from said hopper into an empty bulb therebeneath.

6. Mechanism for unloading bulbs which contain granular masking material after removal from a machine which has processed them by the application of specular coatings to unmasked portions of their interior surfaces, comprising a suction tube, air control members carried by said tube for controlling the flow ofair into a bulb to insure the efficient removal of such masking material, said means comprising a centralizer weight slidably mounted on said tube and formed with a series of apertures to allow a regulated supply of air to be drawn to a bulb during removal of such masking material and acting to hold the bulb more firmly on its support, said weight also being provided with a series of screw holes, a tapered centralizer element secured to the lower end of said weight by means of screws received in said holes, said tapered element conforming with the interior surface at the top of a bulb neck and formed of material which would avoid bulb breakage, grooves in said tapered element aligned with the apertures in the weight, a lower air bafiie secured to the lower end portion of said tube and acting as an inverted funnel to adjust the flow of air thereby, an upper air baffle formed like the lower air baffle but reversed, adjustably secured to said exhaust tube below said tapered part but above said lower baffle to regulate the quantity and velocity of the air entering the bulb to remove such masking material, a first bulb support mounted for vertical reciprocation therebeneath to raise a processed loaded bulb to receive said tube for the withdrawal therefrom of masking material, a vacuum line, a hopper at which said line terminates, a solenoidcontrolled valve in said line, a switch in the circuit to said valve, closed by movement of said support to up position for opening said valve to evacuate said hopper, a solenoid-controlled gate valve at the outlet from said hopper, normally spring-closed to permit evacuation and prevent said hopper from discharging any contained masking material, a second bulb support mounted for vertical reciprocation beneath said hopper, means connecting said suction tube to said hopper for the discharge of masking material thereinto from a raised bulb on said first support,

and switches in the circuit to the solenoid of said gate valve, and respectively closed upon the simultaneous automatic movement of the first bulb support to its down position and the second bulb support to its up position, for opening said gate valve to discharge any masking material from said hopper into an empty bulb on said second support, in order to arrange for first the flow of masking material from a processed 'bulb on said first support into said hopper and, thereafter, allow material to flow from said hopper into an empty bulb therebeneath,

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Bedarrides Ian. 28, 1902 Gieseler 2- May 16, 1922 Johnson May 27, 1924 Fagan et a1 Apr. 9, 1929 Petersen Oct. 13, 1936 Hothersall Jan. 19, 1937 10 Hothersall July 27, 1937 Klux Feb. 28, 1939 Birdseye et a1. July 1, 1941 Minaker Aug. 19, 1941 Hoch Aug. 17, 1948 Hammen Nov. 2, 1948 Green Oct. 2, 1951 Norbom Jan. 1, 1952

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