US3003634A - Lamp inspection apparatus - Google Patents

Description

Oct. 10, 1961 n. L. SNYDER EI'AL 3,003,634

LAMP INSPECTION APPARATUS Filed Dec. 50, 1957 7 Sheets-Sheet 1 INVENTORS y 00mm L. s/vroz/r Oct. 10, 1961 D. L. SNYDER ETAL 3,003,634

LAMP INSPECTION APPARATUS Filed Dec. 30, 1957' 7 Sheets-Sheet 2 O 0, 1961 D. SNYDER EI'AL 3,003,

LAMP INSPECTION APPARATUS Filed Dec. 30, 1957 7 Sheets-Sheet 3 BY 00mm 1.. 51mm 1 C? I ATTOR/VD 1961 D. L. SNYDER ETAL 3,

LAMP INSPECTION APPARATUS Filed Dec. 30,1957 7 Sheets-Sheet 4 It o "3 INVENTORS MAR/(l3 GISLEEEKG ROBERTA. HELW/G DONALD L. 177056 Oct. 10, 1961 D. L. SNYDER EIAI. 3,003,634

LAMP INSPECTION APPARATUS Filed Dec. 30, 1957 7 Sheets-Sheet 5 MAE/US GISLEBEKG KOEK T A HELWIG ATIOR EY Oct. 10, 1961 Filed Dec. 30, 1957 L. SNYDER ETA].

LAMP INSPECTION APPARATUS 7 Sheets-Sheet 6 E Z 70 CdMPARATOR TEST l/N/ 7'0 [/0 VOL7' AJI- SOURCE 70 40 van ac. 0mg

INVENTORS Alli/[l3 GIJLEEMG' KORE/5'74 l/EUY/G DMALD L. .SWYDEK Oct. 10, 1961 D. L. SNYDER ETAL 3,003,634

LAMP INSPECTION APPARATUS Filed Dec. 30, 1957 7 Sheets-Sheet 7 Flg'. l5

INVENTORS MARIUS GISLEBERG ROBERT A. HELWIG DONALD L. SNYDER ATTORNE United States Patent LAMP DJSPECTION APPARATUS Donald L. Snyder and Marius Gisleberg, Montoursville, and Robert A. Hal-wig, Williamsport, Pa., assignors, by mesne assignments, to Sylvania Electric Products Inc.,

Wilmington, Del., a corporation of Delaware Filed Dec. 39, 1957, Ser. No. 705,930

4 Claims. (Cl. 209-1115) This invention relates to the manufacture of electric lamps and more particularly to the manufacture of photofiash lamps.

In the manufacture of photoflash lamps, an hermetically sealed, light-transmitting envelope is usually provided with a filling of combustible foil shredded to filamentary form, a combustion-supporting gas such as oxygen, and ignition means in operative relationship to the combustible. The ignition means usually comprises a tungsten filament supported by a pair of lead-in wires provided with a quantity of ignition paste disposed thereon at or near the juncture thereof to the filament. In the sequency of operations, a lamp envelope provided with a filling of a filamentary combustible is sealed to a lamp mount, the lamp envelope is evacuated, and the combustion-supporting gas such as oxygen is introduced at a precise, pre-determined pressure. If a photoflash lamp is to operate in the proper manner, it is necessary that the initial oxygen fill pressure be maintained and that the lamp envelope be truly hermetically sealed. Even a slight leak in the lamp envelope destroys the quality of the lamp because the contaminating air entering the lamp envelope tends to contribute to the possibility of the lamp exploding and, in any case, the quantity and quality of the light emitted when the lamp is fired is affected adversely.

In view of the foregoing, it has been the practice to test finished lamps for the presence of air. One well known method for conducting such a test is to excite the gases within the lamp with the aid of a standard high frequency coiler such as is customarily used in vacuum work. A blue-green color of this discharge indicates a good lamp whereas a purple color indicates the presence of air. In this test the brightness of the discharge is so low that it must be observed in total darkness. This testing method is time-consuming, expensive and not entirely reliable.

Another testing method is shown and described in U.S. Patent 2,767,325 which issued on October 16, 1956, to F. W. Harjes et al. In the method of the referenced patent, small amounts of contaminating gases are detected and measured accurately by permitting the light from the glowing flash lamp to fall on the cathode of a photomultiplier tube provided with a means for alternately scanning the total light output of the discharge and the light output less the ultra-violet rays, and a bridge circuit associated therewith. The bridge circuit consists of two photo tube load resistors and a galvanometer. The smaller current component, corresponding to the visible light output, is switched to a fixed resistor, and the larger current component, corresponding to the total light of the gaseous discharge, is switched to a variable resistor. The variable resistor is adjusted until the galvanometer reaches zero current indicating that the average voltage drops across the two resistors are equal, and hence the two resistors have the same ratio as the two components of current. The value of the variable resistance is therefore a measure of the degree of air contamination of the fiashlamp.

An object of this invention is to provide automatic apparatus for detecting the presence of contaminants in gas filled envelopes.

Another object is to provide automatic apparatus for A further object is to provide automatic apparatus for detecting the presence of contaminants in gas filled envelopes and rejecting those devices found to contain excessive contamination.

These and other objects are attained in accordance with the principles of this invention by providing a conveyor of the endless chain type with a plurality of lampholders for carrying lamps through a pre-determined path, along which an inspection station and a rejection station are disposed. A contamination detector, including a chamber for enclosing a lamp therein, is disposed at the inspection station. Information concerning the condition of the lamp is obtained at the inspection station and transmitted to the rejection station where defecive lamps are: automatically removed from the line. I

A feature of the apparatus of this invention is the multi-unit contamination detector which, in the specific embodiment described below and illustrated in the accompanying drawings, tests five lamps at a time for the presence of contaminants.

Another feature of the apparatus is the dual produc-E tion arrangement in which an upper conveyor and a lower conveyor operating in synchronism are each provided with an inspection station and a rejection station associ ated therewith, thus in effect, doubling the work load capacity of the apparatus.

In the specific embodiment of the apparatus shown in the accompanying drawings, FIGURE 1 is an end view partly in section of the apparatus located at the inspection station, the lamp-carrying conveyors being omitted for clarity of illustration.

FIGURE 2 is a plan view of the apparatus located at the inspection station with a substantial portion of a cover removed to show more of the apparatus.

FIGURE 3 is an end view, partly in section and on an enlarged scale, of the apparatus at the inspection station, showing the inspection unit associated with the lower conveyor.

FIGURE 4 is a plan view of the apparatus located at a rejection station.

FIGURE 5 is a front elevational view of the apparatus located at the rejection station.

FIGURE 6 is a schematic diagram of an electrical circuit associated with each inspecting device and rejecting device at the inspection station and the rejection station respectively.

FIGURE 7 is a tinting chart illustrating the sequence of operations of the cam operated timing switches in terms of an indexing cycle of the apparatus.

FIGURE 8 is an elevational view of a lamp supporting jaw assembly taken along the line 8-8 of FIGURE 3.-

Referring now to the drawings, and more particularly to FIGURES 3, 4, 5 and 8 thereof, it will be noted that each lamp 113 is carried by a pair of jaws l2 and 14 pivotally mounted on rods 16 and 18 respectively on bracket 20 which is attached to mounting plate 22 on chain 24. The pivot rods 16 and 18 are each provided with a gear 26, the pair of gears 26 meshing with one another at all times. A pair of mounting pins 30 pro ject from the inside face of jaws 12 and 14 and support a spring 32 extending therebetween. An apertured guide 34 is attached to one of the pins 39, the other pin 30' extending therethrough. A pair of cam followers 36 and 38, the function of which will be described hereinafter,- are mounted on the top of jaw 12. I T

It will be noted that each lamp supporting jaw assembly is further characterized by a pair of rollers 40 mounted on bracket 20 and a pair of rollers 42 which are part of the chain 24. The rollers 40 of the lamp supporting jaw as semblies ride in track 44 and the rollers 42 of the chain Patented Oct. 10, 1961 24 ride in track 46. The relative location of tracks 44 and 46 with respect to one another is such that they steady the lamp supporting jaw assemblies or heads and define a fixed path through which the chain 24 moves. The tracks 44 and 46 are mounted on suitable support castings (not shown) which are mounted on and keyed to a main support shaft 51 It will be noted from an examination of FIGURES l and that in the specific embodiment of the invention disclosed in the accompanying drawings, a dual production arrangement is provided whereby similar mechanisms operate simultaneously on lamps carried by an upper and a lower conveyor chain. Since these mechanisms and their actuating devices are substantially the same, only one of the arrangements will be described in detail.

Indexing means, not shown, advances five lamps at a time on each chain conveyor into the contamination check position shown in FIGURES 1, 2 and 3 of the drawings, where five separate testing assemblies are located. Referring now particularly to FIGURES 1 and 2, a pair of standards 52, fixedly mounted on support shaft 50, have a support plate 54 attached thereto and extending laterally therefrom to which a support bracket 56 is attached by screws 57 (FIG. 2). A motor 58, connected to a source of electrical energy by cable 59, is mounted on the shelf portion of support bracket 56, and is provided with a. shaft 60, on the outer end of which a sprocket 62 is disposed. A cover 64, attached to cover support 66 by screws 68, encloses the motor 58 and thus protects it from foreign matter, such as dust, etc. A bank of five light chopper housings 70, is attached to the depending portion of support bracket 56, and a photomultiplier unit 72 is in turn attached to each of the light chopper housings 70 (FIG. 1).. The depending portion of support bracket 56 is provided with five apertures within each of which a bearing housing 74 is fitted, three of these being shown in FIGURE 2, the other two being hidden by the support plate 54. Each bearing housing 74 is provided with bearings on which a shaft 76 (FIG. 3), which supports a sprocket 78, rotates. As shown in FIGURE 3, a pair of ultraviolet-absorbing filters 65 are set in a filter support 67 mounted on the inner end of each of the shafts 76. A photomultiplier tube 69, such as a Type 931 for example, is mounted in a suitable socket therefor in the photomultiplier unit 72 and extends into the light chopper housing 7 0 between the pair of filter elements 65. A glass plate 71 in the form of a window is disposed in the bottom of the light chopper housing 70. A chain 79 meshes with the several sprockets 73, the sprocket 62 and guide sprockets 77, thereby providing means for driving the several shafts 76 associated with the several sprockets 78 from the motor 53 through shaft 69 and sprocket 62. Each of the photomultiplier units 72 is connected to a 1200 volt input supply at terminal 81 The output from each photomultiplier tube is connected through a pair of terminals 82 to a comparator unit described below.

A base member 85 having a bank of live lamp inspection chambers so formed therein is mounted on an end of a support arm 86. A similar base member 85a having a similar number of inspection chambers 84a formed therein is mounted on an end of support arm 88. The top faces of the base members 35 and 85a are fitted with a plurality of strips 87 of resilient material such as rubber which extend about the periphery of the several inspection chambers. The support arms 36 and 88 are fixedly mounted on the upper'and lower ends respectively of a pair of support rods 96 which are reciprocable in bushings in support casting 92. The support casting 92 is provided with a pair of chambers 94, one of which is shown in section in FIGURE 1. A pair of spring posts 96, mounted on support arm 88, are provided with a pair of springs 98, the springs and the spring posts extending into the chambers 4 to insure a steady, smooth reciprocation of the support rods fit during operation. The casting 92 is attached to and supported by support shafts 50 and 101 A cam follower bracket 102, adjustably mounted on support arm 86 by means of screw 104, has a cam follower 1&6 (FIGS. 2 and 3) attached thereto, the cam follower 156 riding on cam 10% on cam shaft 116/. This feature of adjustability is provided to permit slight adjustments in the disposition of the cam follower 166 for reasons which will be pointed out hereinafter. Thus the cam 108 through cam follower 1G6, and springs 98 effect reciprocation of support rods 90 within casting 92 and reciprocation of support arms 86 and 88 to move the bank of lamp inspection chambers 84 and the bank of lamp inspection chambers 84a into and out of encompassing relationship 7 with respect to lamps 16.

material mounted in the bottom of the base member 82a, a pair of electrical contact sleeves 114 extending through and supported by bushings 116 fitted in apertures therefor in block 112, and a pair of sponge electrical contacts 118 fitted into and projecting from the pair of elec-' trical contact sleeves 114, only one of the sleeves 114 and contacts 118 being shown in this figure. When the several lamp inspection chambers 84 and Sea are in their rest position, the lower end of each of the sponge electrical contacts 118 are disposed in water in tanks .119. As

shown in FIGURE 1, the tank 119 associated with the several inspection chambers 84 is attached to the stationary support plate 54. The tank 119 associated with the several inspection chambers 84a as shown in FIGURES 1 and 3 isattached to a suitable stationary support not shown. Due to capillary action, the water in the tanks 119 serves as a means for keeping the sponge electrical contacts 118 moist. Each of the sleeves 114 is spring loaded by a conical spring 120 to insure positive, yet flexible, engagement of the lamp 113* by the sponge contact 118 whenit is moved into operative relationship with respect thereto. One end of an electrical conductor strip 122 is connected to a flange of bushing 116 by screw 124, the other end thereof being secured to the threaded depending portion of an electrical contact holder 126 mounted on an insulator block 128 which is in turn attached to the base member 85a. A spring loaded electrical contact arm 130, pivotally mounted on holder 126, carries an electrical contact roller 132 in frictional engagement with an electrical contact bar 134. As may be noted from an examination of the upper testing unit in FIGURE 1, the electrical contact bar 134 is attached to a contact bar support 136 of insulating material, and the screw 138 defines an electrical terminal for. connecting a source of high frequency electrical energy to the contact bar 134 through cables 135. A cover 140 is attached to the support 136 by screw 142.

After the contamination check has been effected on the two groups of five lamps each by the mechanisms shown in FIGURES 1, 2 and 3, the upper and lower conveyor chains 24 are indexed to bring the lamps into the reject station shown in FIGURES 4 and 5 Information concerning the condition of the lamps, as detected at the inspection station, is received and stored in the circuit illustrated in FIGURE 6 and described below, until the tested lamps reach the reject station. This information is then transmitted to solenoids 152 disposed in housing 154 mounted on brackets 156 attached to the main support shaft 50, the electrical connections from the referenced circuit to the solenoids 152 being made through cable 158. A shrinkage bin 160, provided with five pockets in alignment with the five lamps It) at the gzject station, is also mounted on the main support shaft If a lamp 10 is detected as being defective, its corresponding solenoid 152 is energized when that lamp is at the reject station shown in FIGURES 4 and 5 and the solenoid plunger 162 is actuated. The actuated plunger 162 moves downwardly, striking cam follower 36 on jaw 12, thereby causing clockwise rotation of jaw 12 about its pivot rod 16. Since, as was described above, gear 26 on rod 16 meshes with a corresponding gear on rod 18, the clockwise rotation of jaw 12 about its pivot rod 16 causes counter-clockwise rotation of jaw 14 about its pivot rod 18, thus efiecting an opening of the jaws 12 and 14 to release the lamp which falls into its pocket in shrinkage bin 160. When the solenoid 152 is decnergized, the plunger spring 164 returns the plunger from engagement with cam follower'36, thus permitting the spring 32 which bridges the jaws 12 and 14 to effect a return thereof to the closed position. Further indexing of the conveyor chains 24 advances the good lamps 10 to an unloading station where suitable means not shown deflects the several cam followers 38 to effect an opening of the several jaws 12, 14 and discharge of the lamps to a suitable receptacle.

In the operation of the apparatus described above, photoflash lamps 10 are advanced five at a time by both the upper and the lower conveyor chains 24 into the inspection station of FIGURES l, 2 and 3. With the lamps so disposed, the upper support arm 86 and the lower support arm 88 move the base members 85 and 85a respectively upwardly to bring the several lamp inspection chambers 84 and 84a respectively into encompassing relationship with respect to the lamps. Upward movement of the arm 86 is effected by the cam 108 through cam follower 106 and cam follower bracket 102. The cam 108 also effects the upward movement of the arm 88 through cam follower 106, cam follower bracket 102, arm 86, and support rods 90. The cam follower 106 is adjusted by means of screw 104 to make sure that, at the end of the upward stroke of arms 86 and 88, the strips 87 of resilient material which extend about the periphery of the several inspection chambers 84 and 84a seal the chambers from external light and provide the requisite darkened condition for lamp inspection.

With the lamps 10 enclosed in the several darkened chambers 84 and 84a, and the moistened sponge electrical contacts 118 in engagement with the lamp envelopes, the contacts 118 are energized through cables 135 to effect excitation of the gases in the lamps. The resultant glow in each of the lamps 10 is picked up by the photomultiplier tube 69 (FIG. 3) through the glass plate 71. Since the support 67, to which the pair of ultraviolet-absorbing filters 65 are attached is being rotated by the motor 58, the chopped light received by the photomultiplier tube is alternately the total light output of the lamp and the visible light, the ultraviolet light being absorbed by the filters. The resultant wave form is fed to suitable diiferentiating circuitry in a comparator unit, not shown, which measures the difierences in light output of the glow discharge in the photoflash lamp. Since variations in these differences in light output are a function of contamination in the lamp, the output of the comparator unit may be fed to a thyratron tube which is adjusted to fire only when the contamination exceeds a pre-determined amount. The thyratron tube is connected to line 1 of the circuit of FIGURE 6.

The circuit of FIGURE 6 is one of ten identical circuits wired in parallel to receive, store and transmit information concerning the condition of inspected lamps to the reject station shown in FIGURES 4 and 5. Line 1 is connected to the comparator test unit, not shown. Line 3 is connected to a 110 volt A.C. source. Line 7 is connected to a 40 volt D.C. source. If a lamp has been detected as having more than a pre-determined amount of contamination, a signal through line 1 from the aforementioned thyratron energizes coil relay 9 and closes its contacts 9a and its contacts 9b in the holding circuit. Cam operated timing switch 11 closes, energizing coil relay 13 and thus closing its coil contacts 13a. The closing of coil contacts 13a permits 110 volt AC. power in line 3 to flow through coil contacts 13a and coil contacts 9a, thus the closed coil contacts 9a keep their coil relay 9 energized.

As the indexing starts, to move a set of lamps from the inspection station to the rejection station, cam oper-. ated timing switch 15 closes and energizes coil relay 17. Energization of coil relay 17 eifects a closing of its contacts 17a and thus permits volt AC. power in line 3 to flow through closed coil contacts 17a, and closed coil contacts 912 to energize holding coil relay 19 and close coil contacts 19a and 19b. Immediately after coil relay 19 is energized, cam operated timing switch 21 closes and energizes coil relay 23. Energization of coil relay 23 eifects a closing of its contacts 23a and thus permits 110 volt A.C. power in line 3 to flow through closed coil contacts 23a and the now closed coil contacts 19a to hold coil relay 19 energized. Closed cam operated timing switch 11 now opens, thus de-energizing coil relay 13, opening coil contacts 13a, and dropping coil relay 9 out of the circuit. Coil relay 19, which is being held energized by its own contacts through closed coil contacts 23a, remains energized until the lamps reach the reject station.

When the lamps reach the reject station, cam operated timing switch 25 closes, thus permitting energization of coil relay 27 and closing of its contacts 27a. With 40 volt D.C. power from line 7 now flowing through closed coil contacts 27a and the previously closed coil contacts 192:, the solenoid 152 (corresponding to solenoid 152 in FIG. 5) is energized and the defective lamp is rejected. If the lamp while in the test position had been good, no electrical impulse would have been received by coil relay 9 and it would not have been energized. Consequently, when the good lamp reaches the rejection station, the lamp will not be rejected.

A manually operated, normally open test switch 31 provides a means for testing the circuit since the closingthereof simulates a defective lamp condition. Signal light 33 across solenoid 152 provides a visual means of checking the circuitry therethrough. Signal lights 35, 37, 39 and 41 provide a visual means for checking the oper ation of timing switches 17, 13, 27 and 23, respectively.- In FIGURE 7 line A represents one indexing cycle of the machine with dwell time extending from 0 to about 240, actual indexing movement occurring from about 240 to 360. Line B represents switch 21 open from 60 to and closed during the remainder of the cycle. Line C represents switch 11 open from 270 to nearly 360 and closed during the remainder of the cycle. Line D represents switch 15 closed from 250 to 300 and open during the remainder of the cycle. Line E represents switch 25 closed from 60 to about 105 and open during the remainder of the cycle.

What we claim is:

1. in apparatus for detecting contaminants in a sealed, light-transmitting, gas-filled lamp, by a comparative analysis of the spectral distribution of light from a gaseous discharge within said lamp, the combination of: a conveyor; lampholders, for supporting lamps, mounted on said conveyor; an inspection chamber disposed along the path traversed by said conveyor; a pair of electrodes mounted in said chamber; means for advancing said chamber into encompassing relationship with respect to a lamp held by one of said lampholders on said conveyor and advancing said electrodes into engagement with said lamp envelope; a phototube in light-receiving relationship with respect to a lamp in said chamber; means for energizing said electrodes whereby a glow discharge is produced in said lamp envelopes; and means for alternately passing the total light and the visible light of said glow discharge to said phototube. V

2. In apparatus for detecting contaminants in a sealed, light-transmitting, gas-filled lamp, by a comparative analysis of the spectral distribution of light from a gaseous discharge within said lamp, the combination of: a conveyor; lampholders, for supporting lamps, mounted on said conveyor; an inspection chamber disposed along the path traversed by said conveyor; a pair of electrodes mountedin said chamber; means for advancing said chamber into encompassing relationship with respect to a lamp, held by one of said lampholders on said conveyor and advancing said electrodes into engagement with said lamp envelope; a phototube in light-receiving relationship with respect to a lamp in said chamber; means for energizing said electrodes whereby a glow discharge is produced in said lamp envelope; means for alternately passing the total light and the visible light of said glow discharge to said phototube; a reject st'a tion, disposed along the path traversed by said conveyor, subsequent to said'inspection chamber; means at said rejection station for opening said lampholders; and means, responsive to variations in the difierences between the total light and visible light from said glow discharge received by said phototube, for identifying a contaminated lamp and actuating said lampholder' opening means to effect release of the contaminated lamp there from. r

'3. In apparatus for detecting contaminants in a sealed, light-transmitting, gas-filled lamp, by a comparative analysis of the spectral distribution of light from a gaseous discharge within said lamp, the combination of: a conveyor; a plurality of lampholders, for supporting lamps, mounted on said conveyor; a plurality of inspection chambers disposed along the path traversed by said conveyor; a pair of electrodes mounted in each of said chambers; means for advancing said chambers into encompassing relationship with respect to lamps held by said lampholders on said conveyor and advancing each of said pairs of electrodes into engagement with each of said lamp envelopes; a phototnbe in light-receiving relationship with respect to each of said lamps in said chambers; means for energizing said electrodes whereby a glow discharge is produced in said lamp envelopes;

and means for alternately passing the total light and the 4. In apparatus for detecting contaminants in a sealed, light-transmitting, gas-filled lamp, by a comparatively analysis of the spectral distribution of light from a gaseous discharge within said lamp, the combination of: a conveyor; a plurality of lampholders, for supporting lamps, mounted on said conveyor; a plurality of inspection chambers disposed along the path traversed by said conveyor; a pair of electrodes mounted in each of said chambers; means for advancing said chambers into encompassing relationship with respect to lamps held by said lampholders on said conveyor and advancing each of said pairs of electrodes into engagement with each of said lamp envelopes; a phototube in light-receiving relationship with respect to each of said lamps in said chambers; means for energizing said electrodes whereby a glow discharge is produced in said lamp envelopes; means for alternately passing the total light and the visi ble light of each of said glow discharges to their re-z and visible light from each glow discharge received by its respective phototube, for identifying a contaminated lamp and actuating its respective lampholder opening means to effect release of the contaminated lamp therefrom.

References Cited in the file or this patent UNITED STATES PATENTS 1,626,359 Rundell Apr. 26, 1927 2,183,606 Day Dec. 19, 1939 2,407,062 Darrah Sept. 3, 1946 2,439,373 Stearns Apr. 6', 1948 2,580,275 7 Bickley Dec. 25, 1951 2,734,628 Schlayer Feb. 14, 1956 2,767,325 Harjes et al. Oct. 16, 1956

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