US1600840A - Searchlight - Google Patents

Description

sept. 21, 1926. 1,000,840

-i E. J. MURPHY ET AL SEABCHLIGHT Filed July 9, 1920 5 Sheets-Sheet l' Inventors Edwin lmurpng, Le nard P. Hutt,

Their` Attorneg.

` sept. 21 192s. 1,600,840

E, J. MURPHY ET AL SEARCJHLIGHT Filed July 9. 1920 3 Sheets-Sheet 2 Inventors;

Edwin J. murphg, Leonard P. Hutt,

f3 l ThehA Attorney.

Sept. 21 1926.A 1,600,840

E. J. MURPHY ET Al.

SEARCHLIGHT Filed July 9, 1920 5 Sheets-Sheet 5 Inventors. EdwmJ. murphy Leo ard P. Hutt,

b5 4 T heir` Attorneg Patented Sept. 2l, 1926.

UNITED STATES PATENT OFFICE.

EDWIN J'. MURPHY AND LEONARD I. HUTT, OF SCHENECTADY, NEW YORK` ASSIGNORS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

SEARCHLIGHT.

Application filed July 9,

Our invention has reference to improvements in searchlights, and more specifically to a new design of arc lamp and ventnation system for use in connection therewith. The arc lamp is usually housed in a barrel equipped with a suitable reflector at one end. Its opposite end may or may not have a window, our invention being adapted both to the open or closed type of searclilights.

One object of our invention is to provide a rugged, compact and eilicient lamp unit, which may be readily placed iin and removed from the searchlight barrel, and electrically connected and disconnected with the operating circuit. This unit consistsof a posit-ive and a negative electrode holder or head, the positive hea-d being arranged with the electrode in a horizontal plane, while the negative head has its electrode inclined at an angle pointing upwardly toward the crater end of the posit-ive elect-rode, in accordance with the usual arrangement in modein high intensity are lamps of this general character. A mechanism is provided adjacent the positive head for rotating the anode about its axis and for feet ing it forwardly to compensate for consumption. The negative head is also provided with a. forward feeding mechanism. The electrode heads and the feeding mechanism for the negative electrode form a conipact unit, which is provided with convenient handles for placing it in position. These handles also are arranged to make the electrical connections between the lamp t and the main circuit.

Another object of our invention is to provide a novel system of ventilation to expel hot gases and smoke from the barrel and to cool the electrode heads, the barrel and the reflector. Heretofore it has been necessary to resort to forced draft ventilation in which motor driven fan is used, since the natural ordinary draft was insu'lilicient, especially in high intensity searchlights. has also been found that on some occasions it is necessary to operate the seaichlight at all angles of observation, for instance when exploring the sky for aircraft, which made the use of the forced draft difficult. Our system depends entirely upon the natural draft or chimney effect of the heated g: le surround the arc with a metal chamber, open towards the mirror, and extending 1920.v Serial No. 394,872.

from the bottom and top are two similar draft tubes or chimneys, so arranged that either one or both of these tubes are disposed above the chamber at all angles of elevation of the searchlight. Therefore, in all positions, the gravity effect of the heated gases will produce the proper chimney action to expel the hot gases and smoke.

Other objects and purposes"\of our invention will appear in the course of the following .specification in which we have shown our invention embodied in concrete form for purposes of illustration.

In the accompanying drawings, Fig a side elevation of the lamp unit; I

Fig. 2 is a side view, partly in section of thevnegative and positive electrode heads; li ig. 3 is a detail view of a part of Fig. l f

f l n Fig. l is a perspective view of part of the .lis

-mechanism for feeding the positive electrode;

`F ig. 5 is a section taken on the line .55 of Fig. l, looking in the direction of the arrow indicated and showing the mechanism for feeding the positive electrode;

h Fig. 6 is a perspective view of a searchlight embodying our invention;

Fig. 7 is a perspective view of a searchliglit drum embodying our ventilation system, with our lamp unit shown in a transitory or suspended position;

Fig. 8 is a side view, partly in section of a closed drum type of searchlight, equipped with oui Ventilating system;

- Fig. 9 is a front view of the closed barrel type of searchlight shown in Fig. 8, with part of the ventilator omitted; and

Fig. l() is a perspective view of part of one of the ventilating chimneys.

Referring to the drawings, there is shown in Fig. l a lamp unit which consists of a positive electrode head A and a negative electrode head B, which are each fully described liereinafter. These heads are secured to a common supporting plate l, to form the lamp unit shown.

A positive electrode 2, is supported in a central bore of a casting or frame 3, which frame is provided with a number of eX- ternal radiating ribs 4. The plate l has a suitable opening though which a part of the frame 3 projects until the rib 5 nearest this end engages the plate. The frame 3 is insulated from the plate l by a washer 6,

of mica or other suitable insulating material, and is suitably secured to said plate, as by a screw 7, which screw is surrounded by an insulating` Sleeve S. The end ot' the frame 3 passing through the plate 1 has a wide flanged member T of suitable material, preferably o1E calorized copper set into and secured to it; the of this meml deflect the arc Frame `'rom the main body t-he positive holder and is called an obdurator. At its opposite end, the ifaine 3 has a slot on its under side, extending to the f tral bore in the frame, into which is sl 1..-- bly litted a silver faced blot-,lt or contact` 5) normally urged into the central bore by a spring 10. This inward movement limited b v a liange 11 on the Contact il engaging the frame Yv'hen an eleetrode 2 pushed into the central bore o? the :trame 3, the eentaet 9 will be urget into elo-Se engagement with the electrode, thereby ma ring a goed electrical connection.

The casting),` is formed with a a rm 12 at one end, as shown in Fig'. 2, provided with a. handle 18, ot any suitable insulating material, such as wood or rubber.

The positive electrode 2, is arranged to move toward and away from the negative head B and to rotate about its own axis. This is accomplished by a mechanism con- Sistina ot a trame or stationary cage, indicated as a whole by the numeral 15, and a smaller cage indicated by the numeral 10. journaled within the eagle 15.

The frame 15 is formed at one end by a circular member 17 having' a ilanged enter edge, which member is rigidly secured in any suitable manner to the base plate 1, such as by a number of legs 18, which straddle the frame The other end of the frame 15 is formed by a circular member 19, somewhat similar to the member 1T, ano is united to said member 1T by a number of parallel rods 20, as shown in Fig. 1.

The member 1.7 is provided with a eentrf opening' 21, formed with a small tubular extension shown in Fig. 2, which Serves as a bearing' for the inner cage 1G and a paesage tor the. positive electrode. The member 19 likewise has a central tubular extension 22, shown in Fig. 3, which serves as a bearing for the rear end of the inner cage 1G. i

The inner cage 16 is formed atone end with a bevel gear 23 which has a central tubular extension 21, arranged to lit into the opening` 21, as. shown in Fin'. 2. The rear end of the cage 16 is Jormed of a eirenlar member 25, which also has a central tubular extension 2G, as shown in Fig. 3. This tubular extension 2G lits over tlie tubular extension of the opening` 22, which latter e;- tension has been somewhat reduced in Size to form a shoulder against which thev nie ber 26 abuts. The gear 23 and member are eonneeted to each other by three parallel rods 2T. The Cage 16 is also provided with a long,l screw 2S, journaled at its ends eccentrically in the gear 23 and member 25, respectively. A carriage 2f) is arranged to slide on the rods 2T in a suitable manner, and it has formed in it a nut which engages the Screw 28. This carriage is provided with a screw clamp, indicated by the numeral 250 in L* et, for clamping,r the rear end of the electrode 2.

From the foregoing it appears that the positive electrode 2 pai-zeges through the eentral bore o1 the frame 3, the member 24:, and is atits rear end securely clamped to the inner cage by the clamp 10. This clamp is properly insulated from the carriage 2), as by mica sleeves 31. Therefore, the electrode 2 may be rotated about its own axis by rotating the cage 16. which done by rotatinO' a bevel pinion 32. mounted on the member 1T and whieh meshes with the bevel 23 of the cage 1G.

The forward and baekward niovement ot' the electrode 2 obtained by rotating the sere f' which causes the carriage 2? to move. Tt is desirable to teed the electrode, or move it torwart1 and rotate it sinmltaneously. The rotational movement aeconr plished through the rotation of the bevel pin' in small star whee $13 secureil on the Screw 28 near the forward end of the cage 16, and is arranged to strike a detent 8l n'iounted on the Stationary eagle 15, once dm'inea ch revolution of the inner ca ee 143, as show. in Figi. 5. This gives a partial rotation to Screw LS, and thereby a short movement to the electrode. It is obvious that the distance through whieh the eleetrede ie n'ioved by each revolution ot' the cage 16 is determined by the pitch ot' the Screw 2S and by the Spacing of the points ot the star wheel. Sometimes it is desirable to move the electrode baixward and Jforward rapidly without rotating; it, Jfor example. when a new electrode is placed in the lamp. For this purpose we have mounted on the screw 2S a small wheel which may be readily rotated by the hngers.

The negative electrode 10 is supported in a ventral bore ot a frame or casting #l1 which is rigidly seeureo at one end to a Supporting' arm 4-2, and in Conductive relation therewith, as shown in Fin'. 2.

The suppertiner arm is secured to the bae plate 1 by serews 1121. one of .vhieb ia exposed in Fie'. Cv)z the arm suitably inauated trom late. as by a mica washer The arm so curved that the neri tive eleetrode will be held at a predeterthe positive electrode an angle of 1110 raving been found suitable. +3153 also Secure to the ba e plate 1 an arm 5, whieh is insulated from the plate 1 by a` mica washer etti. Insulating mined angle to l lit) sleeves 46 surround the screws 43, which serve as conductors between the arm and the arm 42, and insulate them from the plate 1. The arm 45 is provided with a handle 47, of insulating material, such as wood or rubber. It will also be seen that the arm 45 has a lug l0 against which the spring 10 bears, and from which it is suitably insulated such as by mica washers 11.

At its free end, the casting 41 forms a nozzle 48 which gradually tapers towards its end. Near its opposite end, the casting 41 is formed U-shaped, as indicated at 49, which serves as a housing or supporting` means for the negative electrode feeding mechanism.

The portion of the casting uniting the structure 49 with the nozzle 48 is of cyliA drical formation and is provided with vertical openings or slotsto accoi'nmodatc electric contacts bearing upon the electrode. A silver contact block 50 is rigidly secured in the lower slot; it extends inwardly a slight distance beyond the wall of the central bore, so that it will hold the electrode clear of the casting. A silver brush 51 loosely fits in the upper slot so that it may engage the electrode and make a good contact with the same. The contact block 50 is connected by an elastic silver band 52 with the brush 51 and is bent around theI cylindrical portion of the casting 41, between the U-shaped structure 49 and the nozzle 48, which band is suitably secured to said block and brush by screws 53. The band 52, in addition to serving as a conducting bridge between the contact 50 and brush 51, also resiliently holds the brush 51 in the upper slot.

The negative electrode feeding mechanism comprises a vertical support 54 suitably mounted in the U-shaped structure 49 and insulated from it. This support may be secured in position in any suitable manner, such as by providing it with a threadef end, which projects through an opening in the bottom of the U-shaped structure and securing it with a washer and nut 55. An axle 56 is journaled in a plane below the edge of the central bore in the support 54; it carries two gears 57 and 58, the former of which is somewhat smaller than the latter, and of such diameter that when an electrode rests on the contact block 50, the electrode will be in frictional engagement at its lowermost surface with said gear 57.

A lever 6() is pivoted at 61 on the leg 62 of the U-shaped structure 49. A second lever 63 is pivoted to the end of lever 60 at 64, as shown in Fig. 2. At one end the lever 63, has a vertical support 65, extending downwardly in the same plane with support 54, and similar in shape with the latter. The support 65 may be secured to the lever 63 in any suitable manner by prefer ence in the manner in which support 54 is secured to structure 49.. An aXle 66 is journaled in a plane above the edge of the central bore in the support 65 and carries two gears 67 and 68, preferably oi the same size as gears 57 and 58 respectively.

At its opposite end, the lever 68 is formed with an arm 7 0 which rests on the silver band 52 directly over the brush 51. An eX- pansion spring 71 is interposed between the end 72, of the lever 60 and the end 78 of the casting 41. The lever 6() is curved to one side so that the spring 71 will not inten fiere with the movement of the electrode through the central bore.

Obviously, the force of the expansion spring 71 will cause the lever 60 ulcrumed at 61 to press downwardly at 64. This pressure at 64 is transmitted to the lever 63, which exerts a downward pressure on the arm and the aXleGG. The pressure exert ed upon the arm 70 is transmitted to the movable silver Contact 51, so that the electrode is properly held between the contact 50 and brush 51.

The force exerted upon the axle 66 causes the gear 67 to frictionally engage the electrode on its uppermost surface, and brings the gear 68 in mesh with gear 58. A suitable rotating mechanism is secured to the axle 56, such as a slidably connected rod 74 with a. turn button 75, as shown in Fig. 6.

The negative electrode is pushed through the central opening of the casting 41 which raises the gear 67 and releases the brush 5l., thereby permitting the free passage of the electrode through the nozzle 48. The spring 71 causes the electrode to be engaged between the contact 5() and brush 51 and bctween the gears 57 and 67 in a manner readily understood. Obviously, by rotating the axle 56 in a clockwise direction, the gears 58 and 68 will cause the electrode to move toward and through the nose lt is, of course, understood that while the electrode is snugly engaged. by the contacts 50 and 51, such engagement is not sufficiently rigid to prevent a sliding movement between them when the axle 56 is rotated.

The electric circuit through the lamp unit thus far described is from the positive side of the source to arm 12 and the Y,Frame 8, through a braided conductor 9 to the silver Contact block 9 and the electrode 2, across the arc to the negative electrode 40, contacts 50 and 51, through the frame 41, the arm 42, screws 48, and arm 45, to the negative side oi the line. The connection of the line with arm 12 and arm 45 will be pointed further on.

In Figs. 6 and 7 is shown an open type of searchlight of drum construction.l formed of a circular frame. or ring 100, to which is secured on one side a barrel 101. forming the wall of the searchlight, and to the opposite side a retlector 102, by Kcreivs 103, or in any other suitable manner, thereby closing one end ot the barrel 101.

A ventilator, designated a Whole by the numeral 104, is preferably formed of one casting ot a length corresponding; to the inside diameter or" the baiel 101, and it also serves as the supportingl :trame tor the lamp unit described, as will presently appear. ator casting;` 101 has an open central chamber its ends, the opening o' parallel vfith the anis of the Jformed With t or chimney elements 10G and 10T trom the chamber 105, as shown i' which are bent outwardly at their ends. This casting` is supp trio arms 10S and 10?, which may part ot the casting` and which ai secured to the trame ring- 100. These aupportinn arms are ot the proper length to so locate the chamber 105 that the focus ot the reflector comes Within the chamaer.

The chimneys and 10T are by similar tubular memberi 110 respectively, which extend nearly angles to chimney members 100, are rigidly secured to the casting` 'form continuous chimneys from eic oi? the chamber 105. The memberi: i 111 pass out of the open end of "he and bent near their ends ii a di re outivai'tV lr and vav from the chamber Y i he ventil said chamber heil D barrel 101. vi'o tubes le, n

The ends of these members are Cappelh with eoivls and 113.

rlhe barrel 101 is mounted on a yoke 111 in the usual manner to permit tl e movement ot the searchlig'ht through all andes of eleration by the hand Wheels 11i. As shown in the uravfing, the casting' 104v is mounted in plan at right angles to the movement of the barrel in the yolie, so that either or both ot the draft tubes 110 and 111 a e disposed above the chamber all angles ot elevation of the searchligiht.

The draft tubes and 111 are provided with dampers S0, one ot which is indicated in Fig'. 10. rllhese dampers are pivote-d at 11G ai d 11T respectively, Which points it will be observed are on the inner side ot the tubes, or the near side to the chamber 105, so that the damper Will drop to open position in the uppermost tube and to a e.; position in the other, in practically all positions ol' the searchlieht. and when not in these positions, both dampers Will be open, for instance, vfhen the eleY-.fation ot tue searehlight is 90 degrees. rl`he operation ot these dampers is automatic, and their movement controlled by gravity.

The conductor 11S from the po .side ot the line is preterably led up throren the tripod 119 or other suppcrt of' tno, tearehhght, around the barrel 101. rhis threaded hole 128, similar to the hole i. From the drawings, it will be seen tha the casting 101- is provided with a pin 1210 on 1h side ot the chamber 105.

the drum by and 41T. and

1 has tifo openings 131inear its upper ovrer ends respectively, arranged to be .n yed by the pins 130 on the` casting; 101. The lamp unit is pushed toi-Ward in the chamber 105 until the plate 1 ene ges the 1.0-11 and the pins 130 emV ye the holes 1o 1, which leaves the lamp unit supported by the casting 101 on said pins. It ivill also be seen that the chamber 105 is tl. roby closed by the plate 1, on itsl outer end, that is, the end aivay from the retlect r, and its inner end remains open. As stated hereinbetore, the chamber 105 occupies a. position Surrounding the focal point and the various parts of the lamp unit and the supportingcasting' 10-1 are so coordinated that the are. may be in the focus. As described above, the electric circuit throreh the lamp unit is from arm 12 to the arm rThe arm 12 is noiv connected to the positive side ot the line by means of a screw of the handle 13, engaging thev hole of terminal 1241, and the negative side is similarly connected by a screv.- 33 of handle engaging hole 128 oit terminal 12T. this arrangement the lamp may be readily placed iu or removed from the drum and the electrical connections established at the same time.

ln order to be able to operate the elec trede feeding and rotating mechanism from the outside ot the searchlight drum, and at the same time not interfere vrith the easy remo val or replacement ot the lamp unit in the drum, We have slidably connected operating' handles to the mechanism. In Fie. 5 is shown the operating handle 150 tor the positive electrode which is fed byY rotating the bevel pinion 32 as described.

rllhis handle which is mounted on the hand Wheel 11dl is pivotally connected to a rod 151, which passes through the member 152 on the shaft of pinion A pin 153 on the shaft 151 lits into a slot in member and as is readily undestood, imparts the motion of the shaft to the pinion. The shaft 151 passes through a cylindrical chamber 154, formed on the hand wheel 114l in which `an expansion spring 155 bearing against a collar 156 on the shaft 151 normally urges the shaft inwardly towards the lamp unit. The handle 151 is formed with a convex cam surface bearing at one point against the surface of the hand Wheel. Therefore, by rocking the handle, the spring 154 will be compressed and the shaft 151 drawn from the slot 152, leaving the lamp unit free to be removed. With reference to the negative electrode, the shaft 56 is rotated by a handle 7 5, connected to a rod 74 in a manner identical with that described with respect to the handle 150 and rod 151 of' the positive electrode. In Fig. 6 the handle 75 is shown in the form of a button, but otherwise the mechanism is the saine as described for the positive electrode. The hand wheel 114 also has the usual screen 157 for viewing the arc. A semi-circular shield 158 is mounted on or forms a part of the casting 104 to permit an unobstructed View of the arc.

When our invention is used with a closed drum type of searchlight, a window 160 is fitted tothe barrel 101 in any suitable manner, and is provided with two suitable open ings 161 through which the chimney or draft members 110 and 111 may pass and a suitable central opening 162 for the lamp unit, as shown, in Fig. 9. From Fig. S it will be seen that the casting 104 iis positioned in the barrel slightly below the outer edge ot the barrel and that the elbow ends of. the chimney parts 106 and 107 thereof project slightly beyond the edge of the barrel. Therefore, when the window is in lace, the ends of chimneys 106 and 107 pro ject through the openings 161. Chimney extensions 110 and 111 are secured to parts 106 and 107 respectively, for this purpose the parts 106 and 107 are each provided with a flanged edge, having inwardly directed hooks 170. These Vlianges are each also provided with a set of openings 171 oli which one opening is shown in Fig. 8.

The parts 110 and 111 each also have a flanged edge arranged to fit the flange of chimneys 106 and 107 respectively. llhese flanges also have a set of pins 172 arranged to fit the openings 171 and thus prevent the parts 110 and 111 from slipping out of position. The parts 110 and 111 are securely held against the chimney parts by means of a set of curved levers 173 pivoted to each of said parts and provided with rings 174 arranged to fit over the hooks 170 as shown in Fig. 8, and thereby lock the parts in position in a manner readily understood. The lamp unit may be readily fitted to the casting 104 through the opening 162 in the same manner as if the glass window were not used.

What we claim as new anddesre to selight, a drinn, a reflector and a ventilating' system ail mounted to rotate about a hori- Zontal axis, said system having a chamber surrounding the source of light and open at its end toward the reflector, tubes extend ing from the chamber out of the drum in opposite directions from each other and at a substantial angle to the axis about which the searchlight rotates whereby one of the tubes acts as a chimney at all angles of elevation of the searchlight.

3. A searchlight comprising an are lamp having a light emitting element, a drum mounted to rotate about a horizontal axis, a reflector and a Ventilating system, the latter having an open ended chamber einbracing the focal region of the rei'iector, means for locating the light emitting element of the lampv in the focal region and draft tubes extending in opposite directions from the chamber at a substantial angle to the axis of' the drum and to the said horizontal axis and out of the drum, the tubes mounted to rotate also about said axis.

4. A seai'chlight comprising a drum and an arc lamp therein, means for mounting said drum for rotation about a horizontal axis, a ventilator for said lamp comprising draft tubes mounted to rotate about said axis with the searchlight, said tubes extending in opposite directions from a point near the lamp to points outside the drum, said. tubes extending substantially at right angles to the axis of rotation of said drum and at a substantial angle to the longitudinal axis of the drum, a gravity damper for each tube for closing the tube when the end oi the tube falls below a horizontal plane througl-i the said horizontal axis.

5. A searchlight compusing` an arc-lamp, a drum, a reflector and a ventilator, the lat-v tei' having an open ended chamber embrac ing the focalV region of the reflector, means for locating the are region of the lamp in the said focal region and for closing one end of the chamber, said ventilator having also draft tubes extending in opposite directions from the chamber substantially at right angles to the axis of the drum along a diameter of the drum and lbeyond the same.

6. A searchlight comprising an arc-lamp, a drum, a reflector whose axis coincides with that of the drum and a Ventilating system,

the latter having an open ended chamber embracing the focal region of the reflector and draft tubes extending in opposite directions from the chamber at an angle to the common axis of the reflector and drum and beyond the latter and means for turning the drum and reflector in a substantially vertical plane passing through the common axis.

7. In a searchlight, a ventilator, an arclamp unit comprising electrode heads and a supporting plate carrying the electrode heads of the unit, said plate electrically insulated from the heads, means for securing t-he supporting plate with its appurtenances to and in proper relation to the ventilator, and manually actuated means for securing and releasing the supporting plate and for making and breaking the lamp circuit.

8. In combination with an arc lamp having a positive electrode said lamp mounted to rotate about a horizontal axis, a double ended iue having an outlet at each end, an intake opening for said flue at a point b'etween said ends, said are lamp supported to register in position with said opening whereby the arc lamp may be placed with its positive electrode in any position of elevation above a horizontal position and preserve an upward draft in the flue against atmospheric pressure, said lue being located substantially at right angles to the said axis.

9. In combination with an arc lamp having a positive electrode lamp mounted to rotate about a horizontal axis, a double ended line having` an outlet at each end7 an intake opening for said tlue at a point between said ends, said lamp supported to register in position with said opening whereby the lamp may be placed with its positive electrode in any position of elevatin above a horizontal position and preserve an upward draft in the flue and a valve in i said flue for )reventing a draft flow toward the intake, said flue being located substantially at right angles to the said axis.

l0. In combination with an arc lamp having a positive electrode, a double ended flue having an outlet ateach end, an intake opening in the flue at a point between said ends, means for rotating the lamp and flue, said lamp mounted to register in position A with said opening, whereby the lamp may be placed with its positive electrode in any position of elevation above a horizontal position and preserve an upward draft in the iue, and a valve mounted in said flue for preventing the reversal of the draft in the flue, said valve so mounted that when the lamp is rotated, the valve is operated.

ll. In combination with an arc lamp having a positive electrode, a double. ended `fine having an outlet at each end and an intake at a point in between, said lamp located in juxtaposition to said intake, means for rotating the lamp whereby its positive electroce may be placed in any `position of elevation above a horizontal position, said flue serving to create a draft for the lamp by way of either end of the flue depending upon the posit-ion of the lamp.

l2. In combination with an arc lamp having a positive electrode, a double ended flue having an outlet at each end and an intake at a point in between, said lamp located in juxtaposition to said intake, means for rotating-the lamp whereby its positive electrode may be placed in any position of elevation above a horizontal position, said flue serving' to create a draft for the lamp by way of either end of the flue depending upon the position of the lamp', said lamp secured to said flue and electric terminals on said flue and electrical connections between said terminals and the electrodes of said lamp.

13. In combination with an are lamp having a positive electrode, a double ended flue having an outlet at each end and an intake at a point in between, said lamp located in juxtaposition to said intake, means for rotating the lamp whereby its positive electrode may be placed in any position of elevation above a horizontal position, said line serving to create a draft for the lamp by way of either end of the iiue depending upon the position of the lamp.A said lamp secured to said flue and electric terminals on said. flue and electrical connections between said terminals and the electrodes of said lamp, a searchlight reflector and a drinn therefor, said lamp in the focal point of said reflector, said flue secured to said drum. electrical terminals on said drum and electrical connections between the terminals on the drum and the terminals on the ilne.

In witness whereof, we have hereunto set our hands this 7th day of July 1920.

EDVIN J. MURPHY. LEONARD P. HUTT.

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