US2449648A

US2449648A - Method of and apparatus for manufacturing flash lamps

Info

Publication number: US2449648A
Application number: US524081A
Authority: US
Inventors: Jr John Flaws
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1944-02-26
Filing date: 1944-02-26
Publication date: 1948-09-21
Anticipated expiration: 1965-09-21

Description

Sept. 21, 1948. J, L ws, JR 2,449,648

METHOD OF AND APPARATUS FOR MANUFACTURING FLASH LAMPS Filed Feb. 26, 1944 3 Sheets-Sheet 1 Invewlrov: John FLaws J11,

His AHrorneg.

Sept. 21, 1948. A u. FLAWS, JR 2,44

' METHOD OF AND APPARATUS FOR MANUFACTURING FLASH LAMPS FiledFeb. 26, 1944 V 3 Sheets-Sheet 2 79 '74 .94 83 l -iiaa --."T v E? 76 75 E? as q 82}; i5 E5 i 120 E 47 645';

lnven tor': John FLawsJYi,

Sept. 21, 1948. .1. FLAWS, JR 2,449,548

METHOD OF AND APPARATUS FOR MANUFACTURING FLASH LAMPS Filed Feb. 26, 1944 3 Sheets-Sheet 3 Arm? r Inven i701. Johri FLaws Jri,

His At tome g Patented Sept. 21, 1948 METHOD OF AND APPARATUS FOR MANU- FACTURING FLASH LAIVIP S John Flaws, Jr., East Cleveland, Ohio, assignor to General Electric Company, a corporation of New York Application February 26, 1944, Serial No. 524,081

11 Claims. (01. 117102) My invention relates in general to method and apparatus for producing photoflash lamp mounts, particularly for photoflash lamps ofthe type commercially known as the Speed Midget or SM and disclosed and claimed in U. S. Patent 2,291,983 to M. Pipkin. More particularly, my invention relates to method and apparatus for applying the fulminating material to the lead-in or support wires of such lamps.

In photoflash lamps of the above-mentioned SM type, the inner end portions of the leadin wires are provided with a relatively heavy coating of fulminating or primer material which constitutes the sole actinic light-producing medium of the lamp. Such photoflashlamps depend almost entirely upon a uniform amount and distribution of the fulminating material on the leadin wires to provide uniform quality lamp performance. The hand application of the fulminating material to the mount lead-in wires, besides being a slow and expensive process, is an extremely hazardous operation due to the highly explosive character of the fulminating material.

In addition, such hand application of the fulminating material to the lamp mounts does not lend itself to the production of beads or coatings of uniform size and shape with the result that lamps of non-uniform flash performance characteristics are produced.

It is an object of the present invention, therefore, to provide novel apparatus for automatically producing uniform size and shape coatings of fulrninating material on the mounts for photoflash lamps of the above-mentioned type.

Another object of the invention is to provide a novel method for producing uniform size and shape coatings of fulminating material on the mounts for such type photoflash lamps.

Further objects and advantages of my inventicn will appear from the following description of a species thereof and from the accompanying drawings in which:

Fig. 1 is a diagrammatic plan view of apparatus according to the invention; Fig. 2 is a fragmentary perspective view of one of the mount holders of the said apparatus with a mountshown in place therein; Fig. 3 is an elevation, partly in section, of the mount positioning mechanism at station D; Fig. 4 is a vertical section on the line i t of Fig. 1; Fig. 5 is an enlarged fragmentary view of the mechanism shown in Fig. 4 for coating the mount, the primer-applying dipper being illustrated in a position 90 from its correct position for purposes of clarity; Fig. 6 is a vertical section, partly in elevation, on the line 6'5 of Fig. 1; Fig. 7 is a perspective view of the cam shaft and associated follower levers for actuating the primenapplying dippers at the various coating stations; Fig. 8 is a diagrammatic illustration of the air jet mechanism at station R; and Figs. 9 and 10 are enlarged views of the coated lower end portions of the mount immediately before and after it is subjected to the air blast at station R.

Referring to the drawing, the apparatus according to the invention comprises a turret or carrier member it rotatably mounted on a vertical shaft H journaled in the bed or base housing [2 of the machine. The turret supports, at regularly spaced points around the periphery thereof, a plurality (24) of heads I3 each arranged to support a lamp mount M in an inverted position. The turret it is intermittently indexed in a counterclockwise direction, as indicated by the arrow in Fig. 1, to advance the heads l3 in turn through the stations A to Y at which the various operations are performed. The indexing of the turret may be performed by any conventional indexing mechanism, such as by means of a rotating drum-type cam l5 mounted on a horizontal drive shaft l6 and engaging with a plurality of rollers I! mounted around the periphery of a spider l8 fastened to the turret support shaft H. Such an indexing mechanism is more fully described in U. S. Patent No. 1,742,153, Stiles et al.

Each head [3 comprises a bracket or arm 19 fastened to and extending radially outward from the periphery of the turret l0 and provided at its outer end with a holder 29 for supporting the lamp mount it. The said holder 26] comprises a block 21 fastened to the outer end of the arm 99 and having a vertically extending, shallow, U or V-shaped groove 22 (Fig. 2) in one of its side faces 23 for receiving the exhaust tube 24 of the lamp mount Hi. The mount is supported in the holder 20 by means of a plate spring 25 which is fastened to the block 2| and holds the exhaust tube 24 in place within the groove 22 while permitting vertical adjustment therein. To permit ready insertion of the exhaust tube 2i between the spring 25 and the side face 23 of the holder block 2|, the outer ends of the spring 25 and block 2! are flared outwardly as indicated at 2B and 21, respectively.

The lamp mounts I4 each comprise a glass stem 28, an exhaust tube 24 sealed thereto and extending outwardly therefrom, a pair of lead-in wires 29 sealed through the stemand having substantially parallel inner lead portions 30, and a small linear filament 3| of tungsten connected o and bridging the inner ends of the inner leads 3D. A short length of wire 32 is connected. to one of the inner leads to serve as an antenna during the glow-testing oi the finished photoflash lamp. In the particular mount M illustrated, the inner leads are formed of wire approximately as mils in diameter and have their innermost end portions spaced apart to provide a gap of approximately 0.1 inch or so.

The lamp mounts M are inserted in the holders 2i? by an operator at the loading stations. A. B and C, the mounts being inserted in the holders in an inverted position, as shown in Fig. 2, with the inner leads fill extending downwardly and the filament ill extending radially of the turret. In loading the mounts Ml into the leads I3, the operator sets them in a position somewhat lower than their ultimate priming or coating position.

From the last loading station C, the heads are carried by the turret to station D where the mount it is set to a predetermined height or vertical-position in the head by suitable positioning means 33 (Fig. 3) located at the said station. The said positioning means 33 comprises a ver-- tically reciprocable push rod 2% which is disposed beneath and in vertical alignment with the mount at station D and is slidably mounted in a bracket 35 fastened to the bed 52 of the machine. The push rod 3 3 moves upwardly into abutting en gagement with the tips or lower ends of the inner leads 3d and pushes the entire mount it upwardly in its holder to the said predetermined height as determined by the upper limit of up- Ward movement of the push rod. The vertical reciprocating movement of the push rod 34 is produced by a horizontally extending lever 3% pivotally mounted intermediate its ends on a shaft 3'! supported on the machine bed It. One end of the lever 36 is pivotally connected to the lower end of the push rod 36 through a link 38 while the other end is provided with a roller 39 which engages a cam 353 on the drive shaft it. Theroller 39 is constantly held in engagement with the cam 45 by means of a spring M one end of which is connected to the machine bed [2 and the other end of which is connected to the lever 35. The cam it is so shaped and mounted on the shaft It as to rock the lever 35 and thus raise the push rod M to the proper mount positioning height, as shown in dotted lines in Fig. 3, during the interval when the mount 54 is positioned at station D.

Following its positioning at station D, the

mount M is carried by the head 53 through idle shown in Fig. 1. The hood 43 comprises arcuateshaped outer and

inner side walls

25 and 45, re-

spectively, a top or cover plate 417, and front and

rear end walls

58 and 49, respectively. The front and rear end walls 68, 39 are provided with suitably shaped openings, conforming more or less closely in shape to the outline of the head and the mount carriedtherebyQto permit passage of the, said head and associated mount through the said end walls. Likewise, the inner side wall 48 of the hood is suitably slotted, as indicated at 59 in Fig. 4, to provide a passageway for the head bracket l9 during the course of movement of the head through the hood.

From idle station H, the mount i5 is carried by the head I? to station J where a first coating of primer or iulminating material is applied to the mount by suitable coating mechanism 5! located at the said station. The said coating mechanism 5i comprises a cup or jar 52 containing a supply of fluid primer material 53 and removably supported-on a bracket 54 mounted on the table portion 44 of the machine bed. A cup-shaped dipper or applicator 55 is vertically reeipro-cable into and out of the cup 52 to carry a small quantity of the fluid primer material up around the lower end portions of the mount lead-in wires 38 and around the filament M. The cup 52 is provided with a protective cover plate 56 having an aperture 5? for the passage or the dipper therethrough during its vertical reciprocating movement.

The: dipper 55 is provided with an orifice 53 (Fig. 5) at the bottom thereof which is normally closed. by a steel ball 59. During the downward movement of the dipper into the cup 52, the ball 59 lifts a slight amount ofi the rim of the orifice'fi to thereby permit flow of the primer material through the orifice and into the dipper. At the same time, the primer material in the cup 52 spills or flows over the rim of the descending dipper'55 tocomplete the filling thereof with the primer material. In order to use up substantially the entire quantity of primer material 53 within the cup 52. before a refilling or a replacement thereof with a filled cup is necessary, the cup (52 is provided with a small well (iii at the bottom thereof? just large enough to accommodate the dipper up to its full vertical extent. To enable the removal of the cup 52 from within the hood dt for replacement with a filled cup or for refilling with additional primer material 53,

the outer side wall of the hood 43 is provided with a door or a removable cover having a window through which the coating operations can be readily observed. The cups 52 are preferably made of a relativel inexpensive material, such as glass, and are preferably discarded, when all the fulminating material therein has been used up, to thereby eliminate the fire and explosion hazard which would attend the cleaning and refilling-oi the emptied cups.

The dipper is supported by a vertically extending rod or wire handle iii fastened at its upperend to'a support arm 6.? overhanging the to a lever 6Q pivoted at one end on a shaft it supported on the machine bed 12. The other end of lever 69 is provided with a roller ll which engages the periphery of an operating cam l2 mounted on' the drive shaft It. A spring l3 connected at one end to the bed it of the machine and at the other end to the lever 69, holds the roller ii in constant engagement with the cam 12.

The cam 12 is so shaped and mounted on the shaft 15 as to raise the dipper 55 to its mount coating position (shown' in dash-dot lines in Fig. 5) during the interval when the mount I4 is positioned at the first coating station J. In the particular case illustrated, the dipper is raised by its operating mechanism to a height suflicient to immerse the inner leading-in wires 30 of the mount to a depth of from 5-7 mm. or thereabouts. On its ensuing down stroke, the dipper 55 is initially lowered at a uniform and relatively slow rate, at least until the inner leads 3!) of the mount are completely withdrawn from the primer material in the dipper. This is done in order to insure against bridging of the primer material between the inner leads 30 and to produce individual and alike coatings on the said leads to. The primer material 53 which is applied to the mount at the first dipping station J is of a relatively thin consistency, comparable to that of a syrup, so as to form only a very thin coating on the inner leads 30.

The primer material 53 applied to the mount ,may be of any suitable composition to provide the desired flash performance characteristics in the finished lamp. Thus, it may be any of the cornpositions set forth in the above-mentioned Pipkin Patent No. 2,291,983. Preferably, however, it is composed of an admixture of potassium perchlorate, sodium chlorate and zirconium (grade 3) powders, suspended in a binder or vehicle of nitrocellulose dissolved in a volatile solvent such as amyl acetate. The vertical reciprocating movement of the dipper 55 in the reservoir 53 of primer material keeps the latter well mixed and prevents the settling out of the heavier particles thereof. To further aid in preventing such settling out of the heavier particles, the cam 72 may be shaped to impart to the dipper 55 one or more vertical reciprocations of short stroke during the interval when the dipper is in its lowered posi tion within the cup 52. Such additional reciprocating movement of the dipper thus produces a puddling action on the primer material 53 within the cup 52.

Because of the relatively quick-drying character of the preferred primer composition which is used, it has been found desirable to provide automatic viscosity control means M for main taining the primer material 53 at the proper consistency. Referring to Fig. 4, the said viscosity control means M comprises a valved container l5, such as a standard drip oiler or oil cup, mounted on top the hood 43 at a point more or less above the cup 52 at station J and containing a supply '26 of amyl acetate or other diluent. The outlet H at the lower end of the container 15 projects through the top wall ll of the hood 43 and is connected to a tube or conduit 18 which extends to a point just inward of the rim of the aperture 5! in the cover plate 56 on the cup 52 so that the diluent passing through the tube drops from the lower end thereof down through the cover plate aperture 51 and into the cup 52.

The stem 19 of the valve 86 in the container 15 projects out the top of the said container and is pivotally connected to a radially extending, lever or rocker arm Bl which is pivotally mounted, at a point outwardly of its connection to the valve stem 19, on an upstanding bracket 82 mounted on the top l! of the hood 43. The outer end of the rocker arm 8| projects outwardly beyond the outer side wall 85 of the hood and is connected by a chain or link 83 to the armature 8st of a solenoid 85 fastened to the outer side wall 35 of the hood. A spring 86, connected between the top 41 of the hood and the inner end of the rocker arm 8|, maintains the container valve 80 6 closed when the solenoid is deenergized. The coil 81 of the solenoid 85 is connected, through leads 88, 89, and a microswitch 90, to a suitable source of current supply. The microswitch Bil is periodically closed by a cam 9| mounted on a motor-driven shaft 92 which rotates at a constant speed. The cam 8! closes the switch 9% one or more times during each revolution of the cam, depending upon the number of switch operating nodes 93 on the cam. in the particular case illustrated, the cam 9| is provided with only one switch-closing node 93 and is rotated at a speed of approximately R. P. M. The amount of thinner or diluent I6 released by the valve 8%? may be adjusted by means of the adjustment nut 94 with which the valve is provided, Where the primer material employed is of the preferred composition set forth hereinabove, the valve Si] is adjusted to feed three drops of diluent to the cup 52 during each interval the valve is open, 1. e., three drops every seconds.

Following the application of the first coating of primer material to the mount at station J, the mount is carried by the head It to the next station K where a stream of air 95 (Fig. 6), from a nozzle 96 disposed directly underneath :and in line with the mount at the said station, is directed against the coated portions of the mount to thereby promote the drying of the suspension or wet primer coatings on the inner leads 3! The nozzle 96 is preferably formed by a tube er the end of which is flattened to produce a narrow slit constituting the orifice of the nozzle. As shown in Fig. 6, the nozzle 95 is disposed with its flattened end extending transversely to the plane of the inner leads 30 of the mount so that the stream of compressed air 95 from the nozzle is directed substantially between the inner leads for the purpose of blowing or breaking apart any bridge of primer material that may have remained between the inner leads. The nozzle 95 is connected by the tube 91 to an arcuateshaped manifold tube 98 mounted on the machine bed l2 and connected to a suitable supply of low pressure compressed air. If desired, the air from the nozzle 96 may be heated in any suitable manner to further promote the drying of the wet primer material on the mount leads til.

From station K the mount I4 is carried by the head 13 to the next station L where a second coating of primer material is applied to the mount by coating mechanism 99 like that located at station J. The dipper 55 of the coating mechanism 99 is reciprooated, as at station J, by a lever I00 (Figs. 1 and '7) pivoted at one.

end on the shaft H1 and pivotally connected at its other end to the dipper operating rod 68'. A cam I0 I, similar in shape to the cam 12, engages a roller I02 on the lever Hill to pivot the latter on its pivot shaft 10, the roller being held in constant engagement with the cam Ill! by means of the spring 18'.

The primer material applied to the mount at station L is preferably of approximately the same consistency as that applied at the firstcoating station J, and it is maintained at the proper consistency by automatic viscosity control means 14 similar to that at station J. The cam (not shown) for closing the electrical circuit through the solenoid coil of the control device "M at station L may be mounted on the same shaft 92 with the cam 9| for the control device M at station J.

By the time the mount reaches the second coating station L, the first coating applied at asses is station J has dried sufficiently to cause the deposit thereon of a second, thin layer of primer material upon withdrawal of the mount from the primer material in the dipper 55. Following the application of this second coating, the mount is successively carried by the head l3 through stations M, N, O, and P where continuous streams of air 95, from nozzles 96 located at each of said stations, are directed against the coatings on the inner leads 36 to promote the drying or setting of the same. As before, the air so directed against the mount may be heated if desired.

At the next station Q, a third and final coating of primer material is applied to the mount by coating mechanism N3 of the same type as at stations J and L. The primer material applied at this third coating station, however, is of substantially heavier consistency than that of the primer material applied at the first two coating stations J and L, so that a relatively heavy or thick coating of primer material remains on the previously coated leads 3t. As at stations J and L, the primer material applied at station Q is maintained at the proper consistency by an automatic viscosity control device M similar to that at stations J and L, the cam (not shown) for closing the electrical circuit through the solenoid coil of such control device at station Q, being mounted on the same shaft Q2 with the cams 9! for the control devices 14 at stations J and L. When the primer material applied at station Q is of the preferred composition previously referred to, the viscosity control device is .so adjusted as to feed only one drop of diluent to the cup 52" every 90 seconds.

The cam Hi l for operating the dipper 55 at station Q is so shaped as to raise the said dipper to its upper mount-coating position in the same manner as at the two previous coating stations J and L, but to lower it more rapidly than at the said previous stations so as to leave considerable primer material high up on the inner leads 30. At the instant the tips or lower ends of the inner leads 30 break the surface of the reservoir of primer material in the dipper .55" during the down stroke of the latter, the dipper is again given a very slight upward movement of approximately 1 mm. or so to thereby reimmerse the leads 38 for a short distance of approximately 1 mm. or thereabouts. As soon as the dipper 55" reaches the upper limit of its reimmersion movement, it is immediately lowered to withdraw the leads 3% from the primer material reservoir in the dipper, thus leaving a bridge W5 (Fig. 9) of wet primer material between the tips or lower ends of the leads 3%. In addition, this reimmersion movement of the dipper $5" at station Q tends to draw away the excess primer material which may have run down off the leads 39.

As soon as the dipper 5.5 clears the head 63 and associated mount Hi during its return stroke down into the cup 52", the turret i ii immediately indexes to carry the head to the next station E where a timed puff or blast of compressed air 596 (Fig. 8), from a nozzle iil'l located directly underneath the mount, is immediately directed against the said mount (i. .e., before the primer material has had a sufficient time to set) to break the bridge Hi5 of wet primer material and lift or roll the same back up ,on the leads 39, thus leaving the filaments! bare or devoid of primer material except possibly for a very fine deposit at some points therealong. The puff of air it, which lasts for only a relatively short period of 8 time such as a fraction of a second or so, is immediately followed by a steady, mild or gentle stream of air from the nozzle it? which then sets the wet primer material enough to prevent its running down the leads 3i! and forming another bridge therebetween.

The nozzle IE1 for producing both the timed air puif Hit and the subsequent steady stream of air at station R is similar to and is mounted in the same manner as the nozzles 96 at the previous air-drying stations, i. e., with its slit-shaped aperture disposed transversely of the plane of the inner leads til of the mount. The nozzle I Ell is connected by a tube N38 to a compressed air line m9 extending from the air supply manifold 98. The tube illil is provided with a valve M18 which is adjusted to reduce the pressure of the air flowing through the said tube to thereby produce only a gentle continuous stream of air from the nozzle IUT. The said nozzle is also connected to the air line 569 through a second tube H5 which is normally closed by a valve iii (Fig. 8) connected therein and opened by a bell-crank lever H2 pivoted on the valve housing H3. One arm 5 I i of the lever l l 2 engages the spring-closed pin i 5 of the valve I i I while the other arm i It of the lever H2 is provided with a roller Ill which ena cam lit mounted on the drive shaft it. The cam H8 is provided with a lift H9 which pivots the lever I l2 about its pivot point to move the valve pin M5 to its open position for a short interval to thereby produce the timed puff or blast of air we from the nozzle ili'l. When the valve iii is subsequently closed, the continuous flow of air in the air line Hi8 then provides the continuous stream of air from the nozme ill] for setting the primer material on the mount lead-in wires st. Under certain atmospheric conditions, it has been found desirable to saturate the air fed to the nozzle it's with amyl acetate to thereby insure the formation of smooth-surfaced beads or coatings on the mount lead-in wires 38. This may be conveniently done by suitably bubbling the air flowing in the line M9 through a pool of amyl acetate. If desired, the air fed to the other nozzles 56 may also be saturated with amyl acetate in like manner.

From station E the coated mount hl is then carried by the head it to station S where another stream of air from a nozzle 5% located beneath the mount and connected to the air supply manifold 98 is directed against the mount to further promote the drying of the primer coatings thereon. The mount is subsequently carried through idle station T where the coatings on the leads 3E3 are further dried in the atmosphere, and thence to unloading stations U to Y where the coated mount is removed from the head is. After its removal from the head the mount antenna wire 32 may be bent or shaped into its final position, as shown in dotted lines in Fig. 10, to thereby complete the manufacture of the mount.

If desired, the top wall l? of the hood (it; may be provided with readily frangible pressure-relief membranes litil, such as Cellophane windows, located directly above each of the primer-containing cups at stations J, L, and Q. Upon the occurrence of any explosion within the hood at one or the other of the coating stations, the corresponding pressure-relief membrane will rupture to thereby divert the force of the explosion upwardly through the top of the hood and away from any person standing alongside the hood,

The hood &3 may be also provided with suitable humidity control means for heating and drying the airwithin the hood when the humidity ofthe atmosphere is toohighto permit proper setting of the wet primer material on themounts and, therefore, proper operation of the machine. Such humidity control, means may comprise a number of electric incandescent lamps mounted in the hood 43 within suitable housings for p1otecting the lamps from any explosions that may occur in the hood. The dryingof theair in the hood may bealso accomplished through the use of calcium chloride or other chemical drying agentsdisposedjin pans within the hood.

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

1. Apparatus for applying .fulminating material to the inner leads ofp'hotoflash lamp mounts comprising a carrier having a head thereon for located intermediate the said two stationsior directing a stream of air against the coating on the'niount to promote drying of said coating, and means located adjacent the path of travel of said head from the last one of the said two stations and arranged to direct an air blast approximate- 1y longitudinally of and against the ends of the said leads to redistribute the fulminating material on said leads.

2. Apparatus for applying fulminating material to the inner leads of photoflash lamp mounts comprising a carrier having a head thereon for supporting the lamp mount, means for advancing said carrier to carry the head and associated mount through a plurality of stations, coating means at one of said stations for applying discrete coatings of a suspension of the fulminating material on the said inner leads, coating means at a subsequent'station for depositing over the first coating another coating or fulminating material of suflicient thickness to bridge the said leads, and means at a subsequent station arranged to direct an air blast approximately longi- Qfithe suspension. in, said cup up around the inner leads of the mount, ,means'for supporting and reciprocating the said dippen; said cuphavingia well at the, bottom thereof just largeyand deep enough to accommodate the dipper when in its lowermostposition inthe cup, and valve means normallyclosingthe aperture in said clipper and adapted ,to open during the downward movement of saididipper through vtlriesuspension in said cup to thereby permitfiow ofsaid suspension through the said aperture and into thedipper.

,5. Inapparatus. for coating the inner leads of photofiash lamprnounts with fulm-inating mate-, rial, the'colfnbination of a cup containing asupply of the fulminating material in suspension; aholder for supporting the mount in an inverted position directly over the said cup, a dipper: verticallyreciprocable into and ,Ol1t 0f said cup for carrying a quantity of the suspension in saidcup up around the, inner leads oithe. mount and means for *supportingand reciprocating; the said dipper, said dipper having, a small orifice at the bottom thereof normally closed by a metal ball resting on thejupper' rim of the said orifice.

. 6. In themanufacture of photoflash lamps, the methodof providing discrete heavy coatings, of a fulminating .material on :the' end portions of closely spaced parallel metal wire supports which method comprises, immersing the said end portudinally of and against the ends of the inner leads to sever the bridge of suspension material and redistribute it on the leads.

3. Apparatus for applying uniform discrete coatings of fulminatin material to the inner leads of photoflash lamp mounts, said apparatus comprising a carrier having a plurality of heads thereon each comprising a holder for supporting the lamp mounts in an inverted position with the inner leads extending downwardly, means for advancing said carrier to carry the heads and associated mounts through a plurality of stations, means at one of said stations for positioning the mount in each of said heads in a predetermined vertical position in its holder, and separate coating means located at a plurality of subsequent stations for successively immersing the said inner leads to a predetermined depth in suspensions of the fulminating material to thereby coat the leads to a uniform extent.

4. In apparatus for coating the inner leads of photofiash lamp mounts with fulminating material, the combination of a cup containing a supply of the iulminating material in suspension, a holder for supporting the mount in an inverted position directly over the said cup, a dipper apertured at its bottom and vertically reciprocable into and out of said cup for carrying a quantity tions ,of,the supports ina liquid suspension of the fulminating material to. form a heavy coating on the supports and a bridge of said material across the supports, and then directing a blast of air substantially longitudinally of and between said supports to sever the said bridge of suspension material and redistribute it on the said supports.

7. The method of providing the endportions of the inner leads of photoflash lamp mounts with discrete heavy coatings of a fulminating material which method comprises, immersing the said end portions of the leads in a. relatively thin liquid suspension of the fulminating material to thereby form a light coating on each of said leads, drying the said light coatin to at least partially set the same, then immersing the said end portions of the leads in a relatively thick liquid suspension of the fulminating material to thereby form a relatively heavy coating on theleads and a bridge of said thick suspension material across the leads, and then directing a blast of air substantially longitudinally of and between said leads to sever the said bridge of suspension material and redistribute it on the said leads.

8. The method of providing the end portions of the inner leads of photofiash lamp mounts with discrete heavy coatings of a fulminating material which method comprises, immersing the said end portions of the lead to a predetermined depth in a relatively thin liquidsuspension of the -fulminating material to thereby form a light coating on each of said leads, dryin the said light coating to at least partially set the same, immersing the said end portions of the leads to substantially the same predetermined depth in a relatively thick liquid suspension of the fulminating material to thereby form a relatively heavy coating on the leads, immediately reimmersing the end portions of the leads to a lesser depth in said thick liquid suspension to form a bridge of suspension material between the leads, and then directing a blast.

of air substantially longitudinally of and between said leads to sever the said bridge of suspension material and redistribute it on the said leads.

9. Apparatus of the class described comprising the combination of means for supporting a photo- 'li r flash lamp mountlhaving closely spaced parallel lead Wires extending i therefrom; means or ooatingtheends- :of said lead wires with a suspension of fulminating material which-*formsa bridge therehetween, v means arranged: to" direct" a blast ofiair approximately longitudinally'ofand against the-said ends of the leadwires to: sever thesaid bridge and. redistribute the coating materialon said lead wires and mechanismiior effecting co-- operation of theseveral means in proper'sequence;

10. Apparatus efthe class described comprising an applicator fori a suspension ofs iulminating material, an air -jet adjacent said container; support means :for holding in alignment with said applicaton a photofiash. lamp mount having closely spaced parallel support wires extending therefrom, means to efle'ct relative movement betweensaid support means and said: applicator tmeffect immersion of said support-wires in the suspension insaid applicator 'to coat said wires and form ;a bridge of "the coating materialbetween the wires; meansi'ormoving said support means torearry' the mount held therebnto a position with its support] wires in longitudinal alignment Withz-Sfiid air. jet; and means for supplying air to said- 'etuata pressure suificient=to=sever the bridge of coating: material and redistribute; it on: the support wires.

11'. @In': the manufactureof pho'toflash lamps, the methodof providingidiscreterheavycoatings oia fulminating amaterial on the end portions of REFERENCES CITED:v 1

The, following references are of. record. in the. file'oi thispatent; Y

UNITED. .STATES. PA'ITENT521v 1' Number Name Date 542393 Meadows July 9, 1895 951,293 Thompson Mar. 8, 1910 1,197,324 Wright Sept; 5, "1 916 1,831,763 Dickerson Nov. 10; 1931 2272586 Ross; Feb.10; 1942 2,291,983 Pipkin Au g l', 1 942 2,329,024 Albright- Sept, 7', 1943 2,363,055 Flaws Nov. 21; 1 944 FOREIGN" PATENTS '12 Number Country Date Great Britain r Mayfi; 192-7