US1817503A - Aerial flare - Google Patents

Description

Aug. 4, 1931. R. J. ANDERSON AERIAL FLARE Filed Feb. 6 1929 m T n 2 m r. mef II n A TJ no r e ID DMJW V1 ID Patented Aug. 4, 1931 i T EEE C E I BOZBERTFJJ ANDERSQN OF WHITMAN, 3M'ASSAOHUSETTS,'ASSIGNOR TO 'NA'IION-ALTFIRE- W'ORKS,;I NC., QB HANORZER, MASSACEUSETTS, A CORPORATION OF MASSA- CHUSETTS AERIAL FLARE Application filedFebruary 6; 1929. Serial .No. 338,003.

This invention relates to improvements in aerial flares such as are used by aeroplanes and other aircraft for landing flares and q signal flares, to determine the drift of the -airship, and for other-purposes.

One of the objects of the invention is to provide meansfor insuring proper ignition of the candle of the flare.

Another object of the invention is to pro- '1 videmeans for delayingthe ignition of the fflare until the same has dropped a predetermined distance.

Another'objec't'of the invention is to provide-a time-burning fuse for delaying the ig- 1' nition-o'f; the candle which will be clampproof and will consequently insureproper ignition of the candle.

Another object of the invention is to;pro-

V 'vide locking means for'the ignition mechanis'm which iscarried by the flare and de tached from the support for the'flare when the flare is released.

These and other objects and features of the invention will more fully appear from '25 the following description and the accompanying drawings and will be particularly pointed out in they claims. a in A 1 preferred embodiment of the invention isfillustrated herein as applied to an aerial flare comprising a candle, a parachute connected thereto,'both enclosed in a casing havingat one end a detachable cap and at the other a stem containing igniting mechanism the actuation of which is caused by the rotation of a propelleractuatedby air pressure during-the falling of the flare.

In the drawings: v

1 isa View, partially broken'away and partially in vertical longitudinal section, of an aerial flare embodying the invention; v

"Fig. 2 is a detail view of the same and 'the igniting mechanism; and, v

Fig.3 is a horizontal sectional view on line 8+3, Fig-"J2 looking downwardly.

The flare illustrated "in the accomp anying drawings comprises a cylindrical cas'ing 1 havingatlits upper end a 'cap'2 provided with a-peripheral flange '8 which fits over the-end of the casingand is'lutecbthereupon 4 and a parachute 5. Thecandle 4 may be of any usual type. As illustrated it. comprises a cylindrical shell f fibrous material, such as Birds pape'rhand a cup-shaped sheet metal .head .7, the peripheral flange 8 of which is connected to theshell'G'by rivets. A staple 9, .which is riveted to the head 7, is

6'1? connected by a suitable cable 10 to a ring 11 which in turn is connected'by cords 12 to the fabric body of the parachute 13. The cable 10 may be coiled within the recess of the cup-shaped head 7 :as illustrated in "Fig. .1. Desirably a protecting device, such as a felt gasket 14, clamped betweenmetallic facing disks, is interposed between the parachute and-the-upperend of the candle.

The shell-*6 of the candle is filled with a flammable, or bursting material 15 and the lower end of said-material desirably is chambered to receive a starting mixture 16,'such as thermite. The charge of the shell is retained therein by a disk 17, and a seal 18 which ts over the lower end of the shell The lower end of the casing is closed by a so sectional dome-shaped head 20. The upper section 21 of the head fits within the casing and is provided with an inwardly turned flange and a suitable packing, such as a felt gasket 22, is clamped between this section of the head and the end of the shell. The lower section of'the head comprises'a cylindrical portion which fits within the casing and the edge of which abuts against the lower edge of the upper section 21.

The dome-shaped portion of the head 20 is of somewhat smaller diameter than the cylindrical portion thereof providing a shoulder 23 upon which the lower end of the 'casing-l'is spun, or otherwise secured.

'The head of the casing is provided with a central stem'24 which contains the igniting mechanism for the candle and extends into proximity to thequi'ckmatch 19. The igniting mechanism comprises a percussion cap, 102

a spring actuated plunger having a firing pin to engage the cap and releasable means for normally locking the plunger in retracted position with the plunger-actuating spring under compression.

The means for releasing the plunger-locking means comprises a propeller having a screw threaded hub so mounted that when the propeller is rotated by air pressure,

caused by the falling of the flare, it will be moved axially away from the end of the stem, and upon a predetermined axial movement will withdraw the locking means from locking position.

In the particular construction illustrated in the accompanying drawings a propeller has a hub 26 which is internally screw threaded and rotatably mounted upon a screw threaded tubular plunger 27 which is reciprocably mounted in the casing. The propeller is normally held in retracted position by mechanism which will hereinafter be described and when the hub ofthe propeller has moved a predetermined distance in an axial direction away from the end of the hub, further movement thereof will cause the release of the plunger locking mechanism, thereby causing the firing of the percussion cap. 7

It has been found in practice that the hub of the propeller may at times become screwed up against the end of the stem with such force as to lock it against rotation, there by preventing actuation of the firing mechanism during the dropping of the flare.

One of the objects of the invention is to provide means for preventing frictional, or other locking, engagement between the hub of the propeller and the end of the stem. This is accomplished in the preferred construction by providing the end 28 of the hub 26 with a shoulder 29 adapted to be engaged by a pin 30 which is seated in and extends from the end of the stem 24.

\Vhen the propeller is turned in the reverse direction from its operative direction, the shoulder 29 will come into engagement with the pin before the end of the hub engages the end of the stem, thereby prevent-- ing frictional engagement between the'end of the hub and the end of the stem. The engagement between the shoulder 28 and the pin 30 is a free engagement so that the propeller cannot be locked against rotation and will immediately commence its proper movement of rotation as soon as suificient air pressure is produced against the vanes of the propeller by the dropping of the flare.

In the use of flares the ignition of the candle has some times occured prematurely and before the candle has dropped a sufficient distance from the airship properly to light up the landing field, or the bursting charge has been exploded too close to the airship.

A further object of the invention is to provide means for insuring suflicient delay in the ignition of the candle to permit it to drop a suitable distance before it is ignited.

The stem which contains the igniting mechanism is formed in two sections, as illustrated in Fig. 2, a main section containing the plunger and its actuating mechanism and a second section which is removably connected thereto and is provided with means for supporting the percussion cap, a chamber containing a slow-burning material which acts as a fuse, and a larger chamber containing a booster charge.

The main section of the stem comprises a cylindrical body 31 having a shoulder 32 adapted to engage the head 20 and a screw threaded portion 33 to receive a nut, or an adapter hereinafter to be described, acting to clamp the flange 32 upon the head. The body 31 is provided with a cylindrical chamber 34 in which the enlarged head 35 of the tubular plunger 27 is slidably mounted. The enlarged head 35 has a central firing pin 36 adapted to engage the percussion cap. The plunger head 35 has a transverse axial bore in which a pair of balls 37 are loosely mounted and the body 31 is provided with diametrically opposite recesses 38 into which portions of the balls may be forced to lock the plunger in retracted position. The lower end of the body 31 is provided with a section 39 having a relatively small bore providing a bearing for the plunger 27. A helical spiral spring 40, which is interposed between the shoulder on the upper end of the section 39 of the body and the plunger head 35, serves to drive the plunger and its firing pin 36 against the percussion cap when the balls 37 are released from locking engagement with the recesses 38.

The balls 37 are normally held in the looking engagement with the body 31, as illustrated in Fig. 2, by central rod 41 which is slidably mounted in the tubular plunger 27 and is provided with a tapered end which is adapted to separate the balls and force them partially into the recesses 38 when in alinement therewith and thereafter to hold them in the position illustrated, thereby locking the plunger against movement with the spring 40 under compression. The opposite end of the rod 41 is provided with an enlarged head 42 which is enclosed in a chambered extension 43 of the hub of the propeller so that as the propelleris moved away from the end of the stem 31 the rod 41 will be engaged by the hub and withdrawn from the locked position illustrated in Fig. 1, thereby releasing the plunger.

The other section of the stem comprises a cylindrical body 45 which has an extension 46 of'smaller diameter screw threaded to engage complementary screw threads mint-o3 upon the innerwall, of theother bodyportion 81. The section :;has at its lower end a shallow central chamber 47 to receive a percussion; cap 48 and a smallbore49 leads therefromto a somewhat larger chamber 50 in which is placed .a damp-proof fibre tube 51 Containing a slow-burning material 52, such as black powder, to form a fuse. The ends of the tube 51 desirably are covered by thin layers of damp proof paper beneath which is placed ,a small pad 53 of gun-cotton, or other sensitive material for insuring ignition of the slow-burning material of the fuse.

The tube 51 is retained in place by a centrally apertured plug 54 which has screw threaded engagement with the walls of an enlarged chamber. 55 which may contain a booster, or flame-producing material, for igniting the quicl'nnatch 19 of the candle. A paper disk 56 desirably closes the upper end of the chamber 55 and is secured in place by spinning a flange 57upon the end of the section .45 over the edge of the tube. Desirably this end of the body is, coated. with a suitable damp-proof composition, such as a paint made of red cinnabar and shellac.

l/Vhen the flare is released from its support in the aircraft and begins to drop, the air pressure upon the propeller-causes the rotation thereof, thereby causing the propeller tomove axially downwardly upon the plunger .27 until the internal shoulder 58 at the base of the chambered head .48 engages the head 42 of the lockingrod 41, and upon .further movement of the propeller withdraws the other end of therod 41 from its engagement with the balls .37, thereby permitting themto roll inwardly out of the recesses 38, thus releasing the plunger. The spring 40 thereupon drives theplungerupwardly andcausesthe firing pin 36 to impinge upon the percussion cap 48, thereby firing the same. he flame fromthe percussion cap ignites the gun-cotton 53 which in,turn ignites the slow-burning material 52 of the fuse. The time required for the burning ofthefuse is such as to permit the flareto drop a considerable distance before the fuse ignites the booster which transmits the flame tothe quickmatch 19 ofthe candle.

In the present construction means are pro iided for venting the gases through the stem in a direction away from the candle. This is. accomplished by providing suitable ports 59 through the plunger head 35, other .ports (30 through the restricted wall39 of the section 31, and ports 61 through the wall of the chambered extension 43 of the hub.

When the firing mechanism .is to ,be cocked or arranged in potentially operative position, the section 45 of the stem is removed and thepiston 35 forced upwardly with a suitable tool until theballs 37enter t re es es h- T r r'el .i theretatedin reverse direction tolcause the look ing rod41 to enter between and separate the balls. The proportions are such when this is accomplished the hub of the propeller will liein proximity to, but not in engagement with the endof the stem, and as before stated frictional locking engagement therebetween is prevented by the co-operating shoulder and pin upon the hub and end of the stem respectively.

After the igniting mechanism has thus been cooked the upper section 45 of the stem, which has previously been loaded as aforesaid, may be screwed upon the section 31 in the assembled position illustrated in Fig. 2, and the stem thereupon assembled upon the head of the shell. The head. may then be applied to and secured to the end of the candle in the manner aforesaid. The flare thus assembled may then be mounted upon the usualsuitable supports upon an airship, means being provided to prevent rotation of the propeller before the flare is dropped.

. hen the flare is dropped and the pro peller released a short period is required before the propeller will have revolved sufficiently to release the plunger and explode the percussion cap. A further desired time interval will elapse during the burningof the fuse before thecandle will be ignited, thereby enabling the flare to be dropped a desireddistance below the airship before the flare becomes effective.

Another feature of the invention consists in providing means for adapting the stem embodying the time-burning'fuse to flares of usual construction. As illustrated herein the screw threaded portion of the stem is providedwith anadapternut 62, see Fig. 1, having an e ternaLQpreferably curved, surface 63 adapted to extend into the aperture in the casing head 20, the casing head being thereupon spun down upon the surface 63 andsweated or secured thereto in any desired manner.

An arm or bracket 64, which desirably is clamped between the flange 32 and the nut 62, extends laterally from the stem 24 and has near its end an aperture 65 through which a locking rod for the propeller extends.

In previous constructions meanshave been provided for locking the' propeller against rotation while the flare is supported upon the flare or torpedo rack of the aircraft. In such constructions the rods, which are secured to the flare support or rack, have extended through guides upon the casing of the fla -re. and into engagement with the edge of, or into an aperture in, one of the propeller blades. Whenthe flare has been released these rods have been retained by the flaresupporting and releasing mechanism until all of the flares have been released,

lil

thereby presenting a series of dangling wires which in certain instances have caused damage.

Another object of the present invention, as stated is to provide a propeller-locking device which is mounted upon and carried by the casing and released from the supporting mechanism of the airship when the flare is released.

In the preferred construction illustrated the casing is provided with a supporting bracket in the form of a separable ring 66 having extensions (37 adapted to be clamped together by a bolt and nut (38 and provided with an ear (39 having an aperture 70 therethrough to receive hook-shaped supporting and reieasing members 71 and 72 which are connected by a pivot 73 and connected respectively to the airship and to suitable actuating mechanism as is usual. The sup porting ring 66 desirably is located at approximately the horizontal plane of the cen ter of gravity of the flare so that but a single supporting ring is required in place of the plurality of supporting devices heretofore employed. A locking rod 74 is slidably mounted in bearings in suitable brackets 75 upon the casing and extends tnroughthe aperture 6-5 in the bracket 64 upon the adapter nut 63. In the present invention a plurality and preferably each of the vanes of the propeller is provided with an aperture 7 6 through which the end of the rod 7 L may be inserted to lock the propeller against rotation. By thus providing an aperture in many or each of the blades the propeller can be retracted upon the tubular extension of the threaded stem 27 until the shoulder 29 engages the pin 30 upon stem, thereby holding the propeller from substantial vibration when the end of the rod 74 is inserted in the aperture 76 in the propeller vane which is then in axial alinement with said rod.

A spiral spring 77 abutting at one end against a bracket 75 and at its opposite end against a collar 78 tends normally to withdraw the propeller-locking rod 74: from locking position with respect to the propeller blades. The opposite end of the rod 7 is provided with means such as a loop 79 adapted to register with the aperture 70in the ear 69 of the supporting rin so that the ring will be also engaged by the co-operating releasable supporting members 71 and 72 which support the flare upon the airship.

In the operation of the device, therefore, the actuation of the releasable supporting devices to release the flare also releases the ring 7 9 of the propeller-locking rod 7 thereby permitting the spring 7'? to retract the opposite end of the rod from engagement with the propeller blade, thus freeing the propeller blade. Inasmuch as the locking rod is permanently mounted upon the casing of the flare it will be carried downwardly with the flare.

As the flare falls the air pressure causes the propeller to rotate and by reason of its screw threaded engagement the propeller moves downwardly upon the tubular extension of the stem until the shoulder 58 of the hub of the propeller engages the head 42 of the locking rod 41. Further downward movement of the propeller withdraws the locking rod from its engagement with the balls 37 thereby releasing the plunger '27 and p rmitting the spring L0 to project the head 35 upwardly and cause the firing pin 36 to impinge upon and fire the percussion cap 48.

An appreciable time is required for the foregoing operation to take place, and a further delay in the firing of the candle is caused by the time required for the slowburning material 52, forming the fuse, so that before the candle is ignited by the fuse and the material 55 in the end of the stem, the flare will have dropped the desired distance below the plane.

When the candle is ignited the gases produced by the combustion of the candle rapidly flll the chamber in the head 20 and build up such pressure that the casing is stripped from the candle and parachute and projected away from them, the cap 2 being detached from the head of the casing. The parachute will then open up and support the burning flare.

The delay thus occurred in igniting the candle is not only advantageous in insuring the dropping of the candle in sufiicient proximity to the landing field properly to illuminate the same, but is also advantageous where planes are flying in formation where a too quick ignition of the flare, after it has been dropped from a higher plane, might interfere with the visibility of the plane flying at a lower altitude.

Furthermore the present invention is par ticularly advantageous in warfare where it is desired to illumine an enemys territory as the ignition of the flare may be sufliciently delayed to permit the airship, from which it is dropped, to pass beyond the field of illumination of the flare before ignition takes place, so that it cannot be seen by the operators of anti-aircraft guns.

Obviously a shell containing a bursting charge may be employed instead of a lightproducing flare within the scope of the invention.

It will be understood that the particular embodiment of the invention disclosed here- 111 is of an illustrative character and is not restrictive and that various changes in form, construction and arrangement of parts, and various uses of the invention may be made, and that the invention may be employed in various other uses within the spirit and scope of the following claims.

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is:

1. An aerial flare comprising a candle, a parachute connected thereto, a removable casing, enclosing said candle and parachute, having a head provided with candle-igniting means comprising a chambered stem containing a percussion cap, a spring actuated plunger having a firing pin, means normally locking the plunger in retracted position against the tension of said spring, a propeller rotatable by air pressure during the falling of the flare having a screw threaded hub engaging said plunger and movable by its rotation axially away from the end of said stem, means operable by a predetermined axial movement of the hub of said propeller to release said locking means and thereby cause actuation of said igniting mechanism.

2. An aerial flare comprising a candle, a parachute connected thereto, a removable casing, enclosing said candle and parachute, having a head provided with candle-igniting means comprising a chambered stem containing a percussion cap, a spring actuated plunger having a firing pin, means normally locking the firing pin in retracted position including a rod movable axially of said stem to release said firing pin, a propeller having a hub rotatably engaging said rod and provided with threads engaging complementary threads upon said plunger rotatable by the falling of said flare to withdraw said rod and to release said firing pin.

3. An aerial flare comprising a candle, a parachute connected thereto, a removable casing, enclosing said candle and parachute, having a head provided with candle-igniting means comprising a propeller having a series of overlapping vanes each provided with an aperture and operable by the falling of the flare to cause actuation of saic igniting mechanism, a propeller-locking rod slidably mounted upon the casing normally having one end engaging the aperture or" a selected propeller blade, a spring normally tending to withdraw said rod fromloclzing engagement, and a loop on said rod adapted to be engaged by a flare-supporting and releasing device operable when so engaged to maintain locking engagement between said rod and said propeller blade, but upon release to permit disengagement thereof, whereby said propeller will cause the actuation of said igniting mechanism.

4. An aerial flare comprising a candle, a parachute connected thereto, a removable casing, enclosing said candle and parachute, having a chambered head provided with a central aperture, means on said casing adapted to be engaged by a releasable flare-supporting device, a chambered stem containing igniting mechanism adapted to be inserted inthe aperture of said head and having thereupon an adapter nut provided with means to be secured to the wall of said head, an apertured bracket extending laterally from said adapter nut, means for causing actuation of said i nitin mechanism includb h ing a propeller having a series of vanes each provided with an aperture, a propeller-locking rod slidably mounted on said casing having one end normally extending through the aperture in said guide arm and the aperture of a selected vane, a spring normally tending to withdraw said rod from engagement with said vane, and means upon the other end of said rod adapted to be engaged by the releasable flare-supporting device and operable when so engaged to retain the propeller-locking rod in engagement with said vane, but operable upon actuation of said flare-releasing device to permit said spring to withdraw said rod from such locking engagement.

5. An aerial flare comprising a candle, a parachute connected thereto, a removable casing, enclosing said candle and parachute, having a head provided with candle-igniting means comprising a chambered stem cont aining a percussion cap, a spring actuated plunger having a firing pin, means normally locking the plunger in retracted position against the tension of said spring, a' propeller rotatable by air pressure during the falling of the flare having a screw threaded hub engaging said plunger and movablerby its rotation axially away from the end of said stem, and having an aperture in each of vanes, means operable by a predetermined axial movement of said propeller to cause ignition of said locking mechanism, a cooperating pin and shoulder located respec tively upon said hub and the end of said stem operable to prevent engagement between the hub of the propeller and the end of said stem, a propeller-locking rod slidably mounted on said casing adapted to engage an aperture in a propeller blade located in axial alinement with said rod when said pin and shoulder are in engagement, thereby preventing rotation and substantial vibration of said propeller, and means operable upon the dropping of the flare to withdraw said locking rod from engagement with said propeller.

In testimony whereof I have signed my name to this specification.

ROBERT J. ANDERSON.

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