US3068756A

US3068756A - Dischargers for pyrotechnic devices

Info

Publication number: US3068756A
Application number: US856714A
Authority: US
Inventors: Schermuly Alfred James
Original assignee: Schermuly Pistol Rocket Apparatus Ltd
Current assignee: Schermuly Pistol Rocket Apparatus Ltd
Priority date: 1958-12-10
Filing date: 1959-12-02
Publication date: 1962-12-18
Anticipated expiration: 1979-12-18
Also published as: FR1242650A

Description

A. J. SCHERMULY DISCHARGERS FOR PYROTECHNIC DEVICES Filed Dec. 2, 1959 A fired-James By Ms ahorneys Sche/mu/y Dec. 18, 1962 $58,756 Patented Dec. 18, 1982 3,068,756 DISCHARGERS FUR PYROTECHNEC DEVHCES Alfred James Schermuly, Newdigate, Barking, England, assignor to The Sehermuly Pistol Rocket Apparatus Limited, Newdigate, Dorking, England, a company of Great Britain Filed Dec. 2, 1959, er. N 856,714 Claims priority, appiication Great Britain Dec. 10, 1958 3 Claims. (Cl. 391.5)

The present invention relates to dischargers for aerial devices such as smoke, signal and illuminating flares and other ignitible or non-ignitible devices which it may be necessary to project through the air. For the sake of simplicity in the ensuing description such devices will be referred to hereinafter as pyrotechnic devices.

Conventional dischargers for pyrotechnic devices are unsuitable for use on aircraft since no provision is made for retaining a pyrotechnic device therein if the discharger assumes a position, under certain flight conditions of the aircraft, in which the open end of the discharger is at a lower level than the base thereof.

The present invention provides a discharger for pyrotechnic devices which avoids the above mentioned drawback.

According to the invention there is provided a combined pyrotechnic device and discharger therefor comprising a tubular casing closed at one end by a plug and at its other end by a removable closure device, a tubular container slidably received in said casing, a pyrotechnic device within said container, a first explosive charge in the casing adapted when ignited to eject the container from the casing, a second explosive charge in said container adapted when ignited to eject the pyrotechnic device from the container, ignitible means in the container initiated by said first explosive charge and adapted to initiate said second explosive charge a predetermined time after initiation of the first explosive charge, an igniter in said plug for igniting said first explosive charge. This pyrotechnic device and discharger works in combination with a projection on the casing adjacent the plugged end thereof; the support member comprising cup means adapted to receive one end of said casing, electrical contact means within said cup means adapted to engage the ignitable means of a casing received within the cup means and initiate the explosive train that finally ejects and ignites the pyrotechnic device and removable retaining means attachable to the cup means for engagement with said projection on a casing received within the cup means to removably secure the casing within said support member.

One form of combined pyrotechnic device and discharger therefor in accordance with the invention will now be described, by way of example, with reference to the accompanying drawing, in which FIGURE 1 is a sectional view of the combined pyrotechnic device and discharger,

FIGURE 2 is a sectional view of a part of the combined pyrotechnic device and discharger of FIGURE I mounted in a support, and

FIGURE 3 is a side elevation, on a reduced scale, showing two supports of the kind illustrated in FIGURE 2 mounted on a common baseplate.

Referring to FEGURE 1, the combined pyrotechnic device and discharger illustrated comprises a casing 1 of circular cross-section formed from a mild steel tube and closed at one end by a light alloy plug 2 which is cannelured into the casing. At its other end the casing 1 is closed by a thin sheet 3 of tin-plate soldered or otherwise lightly secured to the casing.

A conventional electrical igniter 4 is mounted in the centre of the outwardly directed surface of the plug 2 and communicates with a recess in the inwardly directed surface of the plug. This recess contains a Celluloid receptacle 5 closed by a Celluloid cover 6, which receptacle contains a gunpowder charge 7.

The casing it houses a container 8 made from light alloy tube of circular cross-section having an external diameter slightly less than the internal diameter of the casing 1. A light partition 9 is cannelured into the container 8 intermediate its ends. One end of the container 8 is closed by a fusible alloy disc 10 having a centrally disposed aperture therein. At its other end the container is closed by a removable cap 11 made of synthetic resin material.

The container compartment between the fusible disc 10 and the partition 9 is filled with a flare composition 12, a tubular liner 13 of phenolic resin paper being employed to keep the composition 12 away from the internal Wall of the container 8. The container compartment between the removable cap 11 and the partition 9 contains a conventional parachute flare, generally designated by the reference numeral 14. A recess 15' is formed in that surface of the partition 9 which faces the flare l4 and contains a gunpowder charge 16. The latter is retained in the recess 15 by a celluloid disc 17. An instantaneous fuze 18 leads from the flare composition 12 through the partition 9 to the charge 16.

The parachute flare M comprises a light alloy tube 19 internally lined with a reinforced synthetic resin tube Zll. The tube 19 is closed at one end by alight alloy disc 21, and closed at its other end by an aperturcd fusible disc 22, the volume defined by the tube 2% and the

discs

21 and 22 being filled with a flare composition 23. A tube 2.4 of phenolic resin paper is arranged between the disc 21 and the removable cap 11, the volume defined by the tube 2 5, the cap 11 and the disc 21 containing a conventional parachute 25. The connection between the parachute and the flare is accomplished by means of lengths as of wire passing through the eye of a split pin 27 which is mounted in a hole in the disc 21. To ensure the combustion of flare composition 12 following ignition of the charge 7, and the combustion of flare composition 23 following the ignition of the charge 16,

layers

28 and 29 of flash sensitive ignition compositions are placed adjacent the fusible discs it: and 22, respectively.

To ensure that the container 8 will not move relative to the casing 1 during transport and handling, plastic packing discs 30 are employed to urge the container against the plug 2.

When an electric current is supplied to the electrical igniter 4 the gunpowder charge 7 is initiated and the container 8 is ejected from the casing, the thin tin-plate sheet 3 at the end of the casing 1 being blown off in the process. At the same time the flash from the explosion of the charge 7 ignites the flare composition 12 in the container 8. After a predetermined time the flare composition ignites the instantaneous fuze 18 and the latter initiates the gunpowder charge 16 to eject the parachute flare 14 from the container. At the same time the flash from the charge 16 ignites the flare composition 23 of the parachute flare.

A short distance from the plugged end of the casing the wall of the casing comprises a circumferentially disposed portion 31 of greater diameter than the remainder of the casing.

In use of the above described device and referring to FIGURE 2, the plugged end of the casing l is introduced into a support comprising a short tube 32 of circular crosssection having an internal diameter slightly greater than the external diameter of the casing. The external surface of tube 32 is provided with a screw thread, having a diameter slightly greater than the diameter of the portion 31 of the casing. Tube 32 is mounted on a base plate 33 and two diflerent diameters.

has a length slightly greater than the length of easing 1 between its plugged end and the portion 31. The casing is retained in tube 32 by a collar 34 having portions of The portion of larger diameter is internally and is adapted to be screwed on to the ex-- ternal thread of tube 32,, and the other portion of the collar has a diameter slightly greater than the diameter of the casing 1 but less than the diameter of the circumferentially disposed portion 31. The collar 34 is slid over the casing 1 and screwed on to the end of the tube 32 to clamp the portion 31 of greater diameter of the casing against the end of the tube 32. The baseplate 33 is provided with an electrical contact device for conveying an electric current to the electrical igniter in the plugged end of the casing 1.

The electrical contact device on the baseplate 33 comprises a tubular support member 35 having one end flanged and secured to the baseplate 33. The other end of the member 35 is closed by an insulated plug 36 cannelured thereinto. A cadmium'plated contact pin 37 having a flanged portion 38 is urged against the igniter in the plugged end of casing I mounted in the support by a spring 39. The contact pin 37 passes through an insulated bushing 44) pressed into the baseplate 33 thereby maintaining electrical insulation between the contact pin 37 and the baseplate.

FIGURE 3 shows how the support of FIGURE 2 could be mounted in practice. A plurality of discharges (two being shown in FIGURE 3) can conveniently be mounted on the same baseplate 33, the conductors for the electrical firing being connected to a plug and socket connector 41 mounted on a frame 42. To facilitate locking of the collars 34 a pair of diametrically disposed projections 43 are provided on lock rings 44 threaded contra to collars 34, on tubes 32.

Following the discharge of the container 8 from a casing 1 mounted in the support, reloading simply involves unscrewing the collar 34, replacing the empty casing with an un-discharged device, and re-tightening the collar around the new casing.

What I claim is: t

l. A combined pyrotechnic device, discharger support member therefor and aircraft to which the support member is attached, in which the combined pyrotechnic device and dischargcr comprises the pyrotechnic device, a tubular container enclosing the pyrotechnic device, a tubular casing adapted to slidably receive the container when the latter is muzzle loaded into the support member, a plug closing one end of the casing and a closure for the other end thereof adapted to be blown off when the container is ejected from the casing, a first explosive charge in the casing adapted when ignited to eject said container from said casing, ignita-ble means in the container adapted to be ignited by said first explosive charge, a second explosive charge in the container adapted to be initiated by said ignitable means a predetermined time after initiation of the first explosive charge, and an electrical igniter in said plug for igniting the first explosive charge in response to a potential applied between said igniter and said casing, in combination with a circumferential projection around and rolled from the casing, which projection is at right angles to the longitudinal axis of the casing spaced at a distance from the plugged end of the casing and resilient in the longitudinal direction of the casing, the support member comprising cup means adapted to receive slidably therein the short length of easing between the plugged end and the projection, electrical contact means within said cup means adapted to engage said igniter of said casing and initiate the explosive train that finally ejects and ignites the pyrotechnic device, and a removable annular collar retaining means screw threadedly attachable to the cup means after insertion there-in of the casing for attachment with said projection of the casing, the final turning of the collar to tighten the casing in the support causing the edge of the collar to cut into the projection slightly thus ensuring an effective electrical return path for the igniter through the casing; whereby I there is a vibration secure attachment of the collar to the cup and yet the casing is easily removed or replaced.

2. A pyrotechnic device comprising a rigid cylindrical metal tubular casing having a longitudinal axis, a first end and a second end, plug means closing the first end, removable closure means closing said second end, a pyrotechnic object slidably received within said casing, an explosive charge located within said plug means for ejecting said pyrotechnic object from the casing through said second end, an electrical igniter for said charge located within said plug means, means for conveying ignition from said explosive charge to said pyrotechnic object, and a radially symmetrical circumferential out- Wardly directed projection formed on the casing adjacent to, but in spaced relation from said first end, the limits of said projection in the direction of said longitudinal axis each lying in a plane at right angles to said longitudinal axis, in combination with a supporting means therefor comprising cup means surrounding said first end of the casing, and a cooperating annular collar for retaining the casing therein, aid cup means including a base and a right-circular cylindrical wall upstanding from said base having a screw-thread located on the external surface thereof and an internal bore dimensioned to slidably receive and positively locate said first end of the casing, the length of said wall being slightly greater than the distance in the direction of said longitudinal axis between said first end of the casing and the adjacent limit of said projection, a spring-urged electrical contact pin mounted on said base in a position to contact the electrical igniter of a casing received in said cup means, means electrically insulating the cont-act pin from the base, the annular collar comprising a top and a depending circumferential skirt, said skirt having a bore greater than the maximum diameter of said projection and being internally screw-threaded to cooperate with the thread on said cup means, said top having a central hole therein only slightly larger in diameter than the diameter of said casing, the length of said skirt being greater than the overall dimension of said projection in the direction of said longitudinal axis but less than the sum of the overall dimension of said projection and the length of said wall.

3. In a pyrotechnic device comprising a rigid cylindrical metal tubular casing having a longitudinal axis, a first end and a second end, plug means closing said first end, removable closure mean closing said second end, a pyrotechnic object slidably received within said casing, an explosive charge located within said plug means for ejecting said pyrotechnic object from the casing through said second end, an electrical igniter for said charge located within said plug means, means for conveying ignition from said explosive charge to said pyrotechnic object, and a radially symmetrical circumferential outwardly directed projection formed on the casing adjacent to, but in spaced relation from said first end, the limits of said projection in the direction of said longitudinal axis each lying in a plane at right angles to said longitudinal axis, in combination with a supporting means for said pyrotechnic device mounted on an aircraft, the supporting means comprising cup means surrounding the said first end of the casing, and a cooperating annular collar for retaining the casing therein against the severe vibrations encountered in aircraft operations, said cup means including a base and a right-circular cylindrical wall upstanding from said base having a screw-thread located on the external surface thereof and an internal bore dimensioned to slidably receive and positively locate said first end of the casing, the length of said wall being slightly greater than the distance in the direction of said longitudinal axis between said first end of the casing and the adjacent limit of said projection, which said limit rests on the top edge of the upstanding wall of the cup means, a spring-urged electrical contact pin mounted on said base in a position to contact the electrical igniter of a casing received in said cup means, means electrically insulating the contact pin from the base, the annular collar comprising a top and 21 depending circumferential skirt, said skirt having a bore greater than the maxmum diameter of said projection and being internally screw-threaded to cooperate with the thread on said cup means, said top having a central hole therein only slightly larger in diameter than the diameter of said casing, the length of said skirt being greater thm the overall dimension of said projection in the direction of said longitudinal axis but less than the sum of the overall dimension of said projection and the length of said wall, the top of said collar abutting the upper limit of the projection thus to ensure that the projection is gripped tightly along its two parallel limits, and a locking ring on the upstanding wall of the cup means threaded central to that of the annular collar disposed just beneath the same and having diametrically opposed protuberances on its perimeter to facilitate the screwing up of said locking ring tightly against the annular collar to ensure therewith and also in cooperation with the aforesaid projection a mounting of the pyrotechnic device which is secure against all aircraft vibrations.

References Cited in the file of this patent UNITED STATES PATENTS December 18, 196

Alfred James Schermuly It is hereby certified that err after "1n1:emnally" insert central read C a under the heading "UNITED STATES PATENTS" v .632 (:1 ale =Mar, 19, 1957 a (SEAL) Attest:

ERNEST W SWIDER Attesting Officer DAVID L. LADD Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,068,756 December 18 1962 Alfred James Schermuly It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line 5, after "internally" insert threaded column 5, line 19, for "central" read contra column 6, under the heading "UNITED STATES PATENTS' insert 2,785,632 Clauser et alq -Mar., 19, 1957 Signed and sealed this 3rd day of September 1963.

(SEAL) Attest:

ERNEST w. SWIDER DAVID A D Attesting Officer Commissioner of Patents