US3478686A - Target marking device - Google Patents

Description

Nov. 18,1969 R. E. BERG TARGET MARKING DEVICE 2 Sheets-Sheet l FiledAug 25, A1967 INVENTOR ROBERT E. BERG ATTORNEYS R. E. BERG TARGET MARKING DEVICE 2 Sheets-Sheet 2 lNvENToR ROBERT E BERG ATTORNEYS Nov, 18, 1969 Filed Aug 25. 1967 v A VWF:

FIG. 4

United States Patent O 3,478,686 TARGET MARKING DEVICE Robert E. Berg, Redondo Beach, Calif., assigner to Fairchild Hiller Corporation, Bay Shore, N.Y., a corporation of New York Filed Aug. 25, 1967, Ser. No. 663,433 Int. Cl. F42b 25/04, 13/38 U.S. Cl. 102-35 6 Claims ABSTRACT F THE DISCLOSURE A launchable target marking device having a plurality of arms disposed parallel to the longitudinal axis of the charge holder during launching. Upon launching of the device, the charge is released from its holder into a burning position and the arms are released allowing them to move into an angular position with respect to the longitudinal axis of the charge holder.

BACKGROUND OF THE INVENTION Field of the invention This application relates to a launchable pyrotechnic target marking device having improved characteristics with regard to orientation during ight and after landing.

Description of the prior art Pyrotechnic devices including ares and smoke generators, used for purposes such as marking targets and illumination, which have previously been capable of being launched from aircraft, have usually been provided with parachutes for stabilizing the downward descent of the device and for increasing the amount of time the device remains aloft. Parachutes have several disadvantages, however. During descent, the lines of the parachute often snag and tangle cusing the canopy to collapse and the device to plunge to earth. In addition, the heat of a flare or other burning charge can cause the shroud lines to burn, once again causing the canopy to spill. Further, when the device reaches the ground a parachute tends to smother or obscure the device. If the landing is in water, the canopy may drag the device under the surface.

In addition to parachute-type devices, free fall devices have been used. Free fall devices however do not have directional orientation during descent, and in addition may land with the pyrotechnic device buried. In addition, if such a free fall device lands in water, the considerable weight of such a device will cause it to sink.

SUMMARY The present invention eliminates the problems of the prior art pyrotechnic devices and provides a launchable device capable of being launched from aircraft or the ground that is stabilized during downward descent and is oriented to provide optimum burning of the pyrotechnic charge.

In accordance with the present invention, the marking device is provided with a base having an opening for a pressure actuated igniter. A tube of narrower diameter than the base is aixed to the base on the side opposite the igniter and contains the burnable material. The material is retained by a seal across the open end and is so arranged that upon ignition, the seal melts at the same time the main charge is ignited. Means are further provided to move the burnable material out of the holder into the exposed position.

Axed to the exterior of the tube is a plurality of hollow arms which are hinged near the open end of the tube so as to open outwardly. Each of the arms is held in a retracted position by a loose ball which lits corresponding 3,478,686 Patented Nov. 18, 1969 Mice DESCRIPTION OF THE DRAWINGS The invention will be described in greater detail below and in the drawings in which:

FIGURE 1 is a cross-sectional view along the center line of a pyrotechnic device of this invention;

FIGURE 2 is a perspective view of the device with the arms retracted;

FIGURE 3 is a cross-sectional view of the device with the arms extended and the charge expelled;

FIGURE 4 is a cross-sectional view of a portion of the marking device showing details of the locking mechanism for the arms;

FIGURE 5 is a cross-sectional view along line 5-5 of FIGURE 3 showing one of the stabilizing arms,

FIGURE 6 is a perspective view showing the device after launching, `with the arms extended.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to FIGURES 1 and 2, the pyrotechnic device 10 of this invention is provided with a circular base 11 which may be of any suitable material such as aluminum and may be cast or machined. A threaded opening 16 having a depth less than the depth of base 11 is provided in the center of the base and has mounted therein a plug 12 which is provided with complementary threads to those in opening 16. Plug 12 is further provided with a passage 20 in its center in which is mounted a flexible cap 13.

A recess 17 is provided interior of and coaxial with opening 16, but having a narrower diameter. A still smaller recess 1S is provided interior of and coaxial with recess 17.

A Belleville washer 14 is held xed between plug 12 and the surface 17a located between opening 16 and recess 17. The washer 14 has fixed at its center a tiring pin 15 which is aligned behind cap 13. The firing pin 15 in the unred position is located on the side of the washer nearest opening 16. The washer when pushed will snap into a position with the tiring pin 15 on the opposite side of the washer.

Located in recess 18 is a percussion cap 19 of a conventional type. Percussion cap 19 is aligned with ring pin 15 so that pressure on cap 13 will force cap 13 forward against the firing pin 15 causing pin 15 to in turn spring forward striking the cap.

Aixed to the base 11 on its upper side, as shown in FIGURE 1, is a hollow tube 25 which has a smaller diameter than base 11 and is located concentrically with the base. The tube, which is made of a heat-resistant material such as aluminum may be welded or brazed to the base or may be cast as an integral part of the base. Located within tube 25 is the main charge 21. The charge may be any one of the commonly used smoke or light generating chemicals in solid, cake form. The lower end of the charge 21 is provided with a retaining cup 39 which is of slightly smaller diameter than tube 25. The charge 21 and cup 39 are designed to be retained in tube 25 but are capable of sliding outward movement.

A compression spring 34, which is of double tapered design, is located between the cup 39 of the charge and base 11. Spring 34 in its expanded form is shorter than the length of tube 25. The spring is fixed at its upper end 36 to cup 39 and at its lower end 35 to base 11 so that upon expansion of the spring the cup 39 and charge are prevented from leaving tube 25.

Charge 21 is provided with a time `delay fuse 38 located along the longitudinal axis of the charge and in engagement with percussion cap 19. The time delay fuse may be composed of any conventional slow-burning `material. The fuse 38 extends through the top of charge 21 into a first burn layer 22 which is in intimate contact with main charge 21. First burn layer 22 is composed of a material having a high temperature of burning and which is capable of ignition by the material of fuse 38. A wax layer 23 seals the ared upper end of tube 25 and retains the charge and first burn layer 22 in place. Conical opening 24 is provided in the first burn layer to direct the burning 38 toward wax layer 23 when the burning of fuse 38 has reached conical opening 24.

Located on the exterior of tube 25 is a plurality of arms 28 extending substantially the length of the tube. The arms, as shown in FIGURES 1 and 5, are molded of a lightweight material such as polyethylene or polyfoam and are hollow. The inner and outer walls 28a and 28b of the arm 28 are thin and are easily pierced by a sharp or pointed object for a reason to be described below. The exterior wall 28b of the arm is curved so that when the entire outer surface of tube 25 is covered with the arms in a retracted position, -a smooth cylindrical surface is present. Inner wall 28a is curved to conform to the outer wall of tube 25. Arms 28 due to their hollow construction and large displacement are highly buoyant and when afiixed to the device enable the device to fioat.

Afiixed to the top or open end of tube 25 is an angleshaped ring 30 which is held to the exterior of the tube by any suitable means such as welding or a friction bit. An outwardly flared flange 31 at the top of tube 25 retains ring 30 in place. Mounted on ring 30 are a series of brackets 40. A hinge pin 29 located in the end of each arm 28 is pivotally mounted in a pair of brackets 40 so that each arm 28 can move outwardly. A spring 32 having one arm affixed to ring 30 and one `arm aixed to arm 28 is associated with each arm 28 and biases the arm for outward movement when it is released from its position parallel to tube 25.

To lock the arms 28 to the base prior to launching, the outer or free end of each arm 28 is provided with a curved recess 41. A groove 42 of larger size than recess 41 is provided in base 11 and is aligned with recess 41 when arm 28 is parallel to tube 25. Groove 42 in the base is further provided with an insert 26 of a resilient material such as polyfoam. The insert 26 has a recess 43 therein opposite recess 41 in the arm and of generally the same size as recess 41. As shown in FIG. l, one or more heavy balls 27, for example made of metal, are located between the recesses 41 and 43 formed between each arm 28 and the base 11. These balls sit in both recesses and hold the arms in place when the arms 28 are in their locked position parallel to tube 25.

An annular groove 45 is formed on the exterior surface of base 11 and is provided with an O ring 44 so as to seal the pyrotechnic device into its launching tube.

In operation, the pyrotechnic device is loaded with its arms closed, into a launching tube, for instance in an aircraft, with the base of the device toward the breech of the launching tube. O ring 44 seals the device in the tube. Compressed air or other gases expel the device into the atmosphere and at the same time force cap 13 forward against firing pin 15. The firing pin in turn strikes the percussion cap 19 firing the cap and igniting the slow-burn fuse 38 which commences to burn.

At the time that the unit is expelled from the ejection tube, the force of acceleration causes balls 27 to move against the insert 26. The movement of the ball toward base 11 into insert 26 releases the ball from recess 41 in arm 28 thereby freeing the arm and allowing spring 32 to move the arms into an angular position, with respect to the center line of the device. The balls then being unrestrained fall away. In the preferred embodiment of the invention arms 28 are perpendicular to tube 25 in their extended position.

Arms 28, in view of their increased area, will tend to create aerodynamic drag at the top end of the projectile. The projectile will therefore tend to fall base downwardly. The arms 28 will also create an autogyro effect slowing the descent of the device and stabilizing it.

As the device commences its descent or shortly thereafter, the time delay fuse 38 will have reached the first burn material 22 igniting this material. The ignition of this material will melt the wax seal 23 releasing the charge 21 from its restrained position and allowing spring 34 to push the charge outwardly as shown in FIGURE 3. In view of the fact that the spring is attached to the base of the charge and to the base of the device, the charge will remain fixed to the projectile unit. The device in its fully operational configuration with arms 28 and charge 21 extended is shown in FIGS. 3 and 6.

As the device descends, the arms will catch any trees that interrupt the downward `descent of the flare. The material of the arms being of sufficiently weak material, the branches will pierce the arms and hold the device above ground. If the unit strikes firm ground, then the arms will tend to retain the burnable material above ground level since the unit will rest at one end on its base and at the other end on one or two of the arm tips. If the unit should land in water, then the large buoyancy of the arms compared to the pyrotechnic device will cause the unit to float. All of the above features of the pyrotechnic device increase the amount of time the device provides visable light or smoke thereby markedly increasing the efficiency of operation and reducing the need for additional devices.

It is apparent that while one form of mechanism has been shown for retaining arms 28 in place, a variety of mechanisms could be used which would allow the arms to eject upon the application of increased acceleration. For instance, a heavy latch mechanism supported in its locked position by a spring could be used. The latch could, under the inuence of acceleration, open against the spring allowing the arms to move outwardly.

In addition to the arm configuration disclosed herein, the arms can be of any preferred shape. For instance the number and size of arms can be varied for various desired buoyancies. They may also be varied in size to accommodate the device to the diameter of the launching tube.

It is to be understood that the device shown herein is merely by way of illustration and that the scope of protection of this invention is to be determined by the claims herein.

What is claimed is:

1. A launchable pyrotechnic device comprising a pyrotechnic charge, means for holding said pyrotechnic charge, a plurality of arms hingedly mounted at one end thereof to said holding means and foldable with respect to said holding means and extendable generally radially therefrom, means mounted on said device responsive to acceleration for retaining said arms in a folded position parallel to the holding means during launching and for extending said arms into `a position perpendicular to the holding means after launching of the device, said last-named means comprising a recess in the unhinged end of each of said arms, a recess cornplementary to each recess in said arms located on said holding means, resilient means affixed to the interior of said recesses on said holding means, a ball associated with each pair of recesses and located partially in both recesses and a spring biasing the arms into their extended position, whereby the acceleration force during launching will move said balls fully into the recesses in the base releasing the arms and said spring will bias the arms outwardly.

2. A device according to claim 1 further comprising means for extending the charge from said holding means after launching of the device.

3. A launchable pyrotechnic device comprising a housing, a pyrotechnic charge located within said housing, a plurality of vane stabilizing arms, means for hingedly mounting said arms to said housing adjacent one end thereof to permit said arms to be released to a position extending generally radially from said` housing, means for holding said arms in a folded position generally parallel to the housing before and during launching and for releasing said arms to said extended position lafter launching, cover means ori said one end of said housing, means for removing said cover means after launching, and means for raising said pyrotechnic charge through said one end of said housing after removal of the cover means from Within said housing to a position where its major portion extends above said radially extending arms.

4. A launchable pyrotechnic device as in claim 3 wherein said means for raising the pyrotechnic charge comprises a resilient means located between said charge and the other end of said housing, said resilient means normally urging said charge against said cover.

5. A launchable pyrotechnic device as in claim 4 wherein said cover means comprises a meltable seal which melts upon ignition of the charge.

6. A device according to claim 3 wherein the means for retaining said arms in a folded position and extending said arms comprises a recess in the unhinged end of each of said arms, a recess complementary to each recess in said arms located on said housing, resilient means -aixed to the interior of said recesses on said housing, a ball associated with each pair of recesses and located partially in both recesses, and a spring biasing each arm into its extended position, whereby the acceleration force during launching will move said balls fully into the recesses in the base releasing the arm and said springs will bias the arms outwardly.

References Cited UNITED STATES PATENTS 1,879,840 9/1932 Brandt 244-3.28 1,964,016, 6/1934 Wiley IGZ-35.4 2,044,819 6/ 1936 Taylor 102-4 2,595,939 5/1952 Griffith l02-37.4 2,969,211 1/1961 Von Saurma 102--4 X SAMUEL W. ENGLE, Primary Examiner U.S. Cl. X.R. LOZ- 4, 34.4, 37.1

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