US2349980A - Forest fire extinguisher - Google Patents

Description

May 30, 1944. L. w. MOORE FOREST FIRE EXTINGUISHER INVENTOR ATTORNEYS W/lfaora lfflVlf/IlilI/IA/lV/III I I!!! ljrzdy' Filed June 21, 1940 Patented May 30, 1944 UNITED STATES PATENT OFFICE FOREST FIRE EXTINGUISHER Lindley W. Moore, Baltimore, Md.

Application June 21, 1940, Serial No. 341.169

1 Claim. (Cl. 102-2) My invention relates to new and useful improvements in fire extinguishers.

An important object of my invention is to provide a fire extinguisher that is uniquely constructed to permit the same to be dropped from an aeroplane and that is particularly adapted to be used for fighting forest fires, prairie fires and like confiagrations susceptible to treatment in this manner.

Another object of my invention is to provide a fire extinguisher of the above-mentioned character that includes an explosive powder which is detonated as soon as the bomb strikes an obstructing object, the explosion hurling a suitable fire extinguishing chemical contained by the bomb onto the ground and trees immediately surrounding the point at which the bomb strikes.

Still another object of my invention is to provide a fire extinguisher of the above-mentioned character that is adapted to be detonated or exploded a substantial distance above the ground in order to most effectively disperse the fire ex tinguishing powder.

Yet another object of my invention is to provide a fire extinguisher of the above-mentioned character that includes provision for exploding the bomb in the event that it should fall into a tree or bush and thus be'prevented from contacting the ground.

Other objects and advantages of my invention will be apparent during the course of the following description.

In the drawing, forming a part of this specification, and wherein like numerals are employed to designate like parts throughout the same,

Figure 1 is a front elevation of a device embodying my invention,

Figure 2 is a longitudinal sectional view of my device, showing parts broken away and illustrating parts in section and parts in elevation, and

Figure 3 is a transverse sectional view taken on the line 33 of Figure 2.

In the accompanying drawing, wherein for the purpose of illustration, is shown a preferred embodiment of my invention, the numeral Ill designates a hollow shell which is generally tubular in its formation, the end ll being closed and rounded and the end l2 thereof being tapered slightly inwardly. The shell may be constructed of any suitable plastic composition which is inherently frangible but which possesses a sumcient rigidity to withstand the normal shocks to which it may be subjected during handling and transportation.

The disk-shaped head I3 of the body it closes the tapered open end I2 of the shell, the peripher of the head being in register with the outer periphery of the shell. The inner face I5 of the head slopes from the body to the periphery thereof and provides a frusto-conical striking surface from which the fire extinguishing chemical contained by the shell is deflected when the device is exploded. The body is of elongated cylindrical formation and extends axially through the shell and through a central opening I6 in the closed end ll thereof. The portion of the body extending beyond the shell is externally screw threaded to receive the nut i1 which abuts the portion of the shell circumjacent to the opening l6 and holds the abutting face of the head i3 in pressed engagement with the end l2 of the shell. The compartment formed. when the shell is closed by the body is filled with a suitable fire extinguishing powder i8 and an explosive powder IS. The explosive powder is packed around the body it and retained in association therewith by a membranous sack 20 while the fire extinguishing powder is packed into the space between the inner peripheral wall of the shell and the membranous sack 20.

The extinguisher is adapted to be attached to and released from an aeroplane and it is, therefore, necessary that it be guided in its travel from the plane to the ground, The tail assembly 2i comprises frusto-conical shell 22 the open base of which is snugly received within a peripheral groove 23 in'the head of the body l4. As clearly shown in Figures 1 and 2, the outer surface of the frusto-conical shell registers with the periphery of the head to provide a substantially streamlined shape. The shank portion 24 of the pin 25 extends axially through theshell 22 and the distal end thereof is screw-threadedly received by the boss 26 of the head. The enlarged head 21 of the pin is in the form of an eyelet and includes a projecting shoulder 28 which abuts the apex of the frusto-conlcal shell and holds the same fixedly associated with the shell ill. Diametrically opposed right angularly disposed fins 29 project radially from the shell 22 and maintain the extinguisher in a vertical position during its travel through the air.

A detonating mechanism 30 is applied to the r lower end of the aerial bomb thus formed, which mechanism is adapted to strike the ground a substantial distance in advance of the shell and to discharge the explosive powder iii. The body I I is provided with an axially extending internal bore 32 one end of which opens through the projecting end of the body and the other end of which terminates at substantially the middle of the body in a transverse passage 33 which opens through opposite sides thereofeand against the explosive powder 19. One end of the rod 3i is slidably received within the.central bore 32 and a tubular extension 34 slidably receives the extending portion thereof. One end of the extension is provided with an internally screwthreaded socket 35 which detachably connects Jecting end of the body. Ilhe extension is generally elongated and the distal end of the bore is enlarged to accommodate the coil spring As best illustrated in Figure 2, the distal end of the radii terminates within the enlargedv portion of the bore and screw-threadedly receives the inner end of the striking pin 31. The pin is 2,349,980 with the screw-threaded extremity of the pro-' gage the ground and detonate the bomb. If the confiagration is in the nature of a forest fire and the bomb drops into a tree the ring 4| will be slidably received within the bore but is normally held against sliding movement therein by the spring. Additional means in" the form of a locking bolt 38 is provided to positively prevent sliding movement of thepin. The locking bolt extends transversely through the tubular extension and pin to positively hold the same against slidingmovement and the nut 38 is carried by its extending end to hold the same against casual displacement. The inner end of the rod 3| is v ointed and terminates a substantial distance from the transverse passage 33 when the rod is in the locked position. The portion of the bore not detonate the cartridge 40. I have, therefore,

provided a ring 4| which is arranged in circumferentlally spaced relation with the butt'end of the bomb and which connects with the rod 3| by the arcuately bent radial arms 42. The'ends of the arms connecting with the rod extend through registering elongated slots in the body which permit longitudinal-travel of the rod, within the body a suflicient distance to engage and to detonatethesame. l

The tail assembly, body M and detonating mechanism are preferably formed of a suitable metallic material while, as hereinbefore described, the shell I is formed of a relatively frangible or shatterable material. In order to insure a maximum of safety, I have found it expedient during normal handling and transportation of the bomb to remove the detonating mechanism and cartridge from the assembly. The mechanism is disengaged from-the assembly by unthreading the socket 35 of the. extension from the projecting end of the body and pulling the inner end of the rod 3| from the bore of the body. The cartridge may then be easily removed and danger of premature explosion is reduced to a the cartridge minimum. When it is desired to use the bomb,

the cartridge may be easily slipped into the bore 32 of the bomb and the detonating end of the rod 3| thereafter inserted into the bore. The socket 35 may then be expedltiously'threaded onto the engaged by branches of the tree and will operate as effectively as the striking pin 31 to slidably actuate the rod 3| into engagement with the cartridge.

As soon as the cartridge is detonated, the explosion gases will have access to the explosive powders l9 through the transverse passage 33 and firing of the explosive powder will cause the shell in to shatter so that the fireextinguishing body and the locking bolt 38 slipped into place.

The bomb is then. ready forum and it is only necessary to remove the locking bolt to render the same in ,condition to be dropped from the:

is preferably suspended y a cable.

powder l8 may be widely scattered.

By reason of the fact that the present construction is adapted to explode the shell at a minimum ofeight or ten feet above the ground,

it is necessary that some means beprovided for scattering the extinguishing powder evenly over surrounding terrain. I have, therefore, uniquely shaped the portion of the body extending through .the shellto direct the particles of powder l8 when the same is impinged outwardly by the explosive force of the powder l9. As illustrated in. Figure 1, the bomb. will be positioned a substantial distance above the surface of the ground when the same is detonated and the particles of fire extinguishing powder which are impinged upv wardly by the explosion will be deflected outwardly by the conical striking surface ill of the head IS. The body is formed adjacent the lower end of the powder sack with a peripheral ridge G3 which converges at its opposite sides toward the periphery of the body to provide annular striking surfaces 44 and 45. The detonation of the bomb will cause a'portion of the powder II to be directed outwardly and upwardly by the upper surface 44 and the portion of the explosive powder disposed below the surface 45 will react thereagainst to direct the fire extinguishing powder outwardly and downwardly and against the burning bushes and grasses immediately surrounding the bomb. 7 l 7 It is to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred example of the same, and that variouschanges in the size, shape and armanagement of parts may be resorted to without departing from the spirit of my invention, or scope of the appended claim. Having thus described my invention, I claim: A fire extinguisher comprising a frangible shell, a layer of powder adapted to extinguish fire lining the inner periphery of the shell, an explosive powder disposed within the layer of fire extinguishing powder, a body extending axially through said explosive powder and having a cartridge chamber opening against the said explosive powder and through one end of the body, a detonating mechanism detachably secured to the mentioned end of the body. parts of said mechanism being movable into engagement with a cartridge disposed within the chamber, the

said body being formed at its end remote from the detonating mechanism with an enlarged head portion having a frusto-conical shaped side confronting the explosive powder and at its end ad- I jacent the detonating mechanism with a circum ferential rib presenting oppositely sloping sides to portions of the explosive powder, the said body parts being adapted to direct the particles of fire extinguishing powder when the device is exploded.

LINDLEY W. MOORE.

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