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Publication numberUS2557448 A
Publication typeGrant
Publication dateJun 19, 1951
Filing dateMay 13, 1944
Priority dateMay 3, 1943
Publication numberUS 2557448 A, US 2557448A, US-A-2557448, US2557448 A, US2557448A
InventorsMathisen Anders
Original AssigneeGraviner Manufacturing Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Explosive device for use in fire fighting equipment systems and the like
US 2557448 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

June 19, 1951 A. MATHISEN 2,557,448

ExFLosIvE DEVICE FoE UsE 1N FIRE FIGHTING EQUIPMENT sYsTEMs AND THE LIKE Filed May 15, 1944 Patented `une 1.9, 1951 THE LIKE Anders Mathisep, Isleworth, England, assigner to Graviner Manufacturing Company Limited; Isleworth, Middlesex, England, a British corpo;

Application May 13, 1944, SerialNo. 535,508 In Great Britain May 3, 1943 This invention relates to improvementsin explosive devices of the kind adapted to use in Afireghting equipment systems, fire-extinguishing apparatus,Y electrical switch devices and for similar purposes.-

Inorder to obtain actuation of apparatus parts and appliances in fire-fighting systems and the like it has been proposed to use small explosive charges in the discharge heads of re extinguishers and the like, and to ignite such charges by small electrically ignited fuses capable Aof energisationby closure of electrical switch de-Y vices such as manually operated push button switches, llame or re detecting switches, and crashor inertia andv gravity element opera-ted switch devicesV and the like.

The object of the `present invention is to provide a compact explosive device capable of igni tion, preferably by electrical means but if desired also' by percussionv means, whereby a mechanism actuating or securing Amember is capable of dis placement by an explosive' charge to effect required operation of apparatus, mechanical or electrical: devices andthe like,

To this end the present invention-consists in an explosive device comprising a tubular mem; ber to which a stud member is secured by meansof a frangible rim, a4 closure member being adapted. to be inserted into the tubular member to form an explosive substance4 containingl chamber between one end of said stud and said elosure member, means being provided for igniting said explosive substance to displace the stud member.

The closure member may be provided witha longitudinal fine bore conduit,Y and an electricalltr energised fuse mounted for example in a suitable metallic fuse holder adapted to be securedinthe tubular member,may be provided for ignitingf the said. explosive substance through the -conduit.

The closure member isV preferably provided withY a projection adapted to protrude into saidl explosive substance,Y the ne bore conduit termi nating in a y blind end in said projection, one or more ne holes being producedrtransversely in said projection sonas to` connect withA saidconduit,.- ignition of the explosive substance being effectedthrougli saidconduit and hole or holes ina substantially centralposition inl the mass of explosive substance.

7 Claims". (c1. isi-fissi In one form of the invention-the niei'riber may be provided witha restricted bore one end into which said stud member is adapted to fit,` a-thin rim being then provided upon member which rim fit's inside the tubular member so as touabutdagainst the end o the restricted bore portion of the tubularV member:r d i In one form ofthe invention, thea rim of the stud membernand the closure member may Abe 16" spaced by a sleeve adapted to form the explosive containing chamberi and said sleeve and the clcsure membermay be screw-threaded so as to be secured together. I n this form of the inventid the lrim of the stud member may be `secured t6 said sleeve by soldering, brazing or the lillevso that these parts form anuexplosive containing chamber capable of insertion into the tubular member, in which they may be secured by the rnetallic ignition deviceholde member,l which membermay serve to lock the parts irmly position.

`While the ignition means may be in any desiredform sulras a percussion device prefer4 ablyan electricallyignited fuse is secured in said ignition device holder;v said fuse comprising an electric current-)heated element and van ightioncompoundsubstane adapted to ignite said explosive substance tlrougli the said conduit and holes' in the cl's'viire device.

The device of the present inventief; has` nuriferou's applications and i one form th tubular member s in the shape f' s cap de ice' adapted'to be secured in a; uidA cockY device bc the stud memberY bein'iadapted to engage a ccl shut-oiplgarrangd to close the said cock against iluid How upon ig''iticn of said explosive substance- As the force which can be applied to the thin rim o f meta-l upon the stud is` limited, the tubular member may be secured;- for exarfnple, in a hous-l ing, and the studt may b e elongated ao. disposed transversely across a space in said housing inI which said transversely disposed stud mayV serve' as an abutment for an; actuating member ar'- ranged to, operate any type of mechanism;` the4 4`5 force applied by said actuating member being; therefore taken by a thrustv at right anglesz to the axisof the stud which does not apply force tubera. l., t,

In a, delay action electric switch device the tubular memberV may be secured to a fuse holder 3 containing a delay action fuse, the stud member engaging electric switch actuating mechanism adapted to operate electric contacts upon ignition of said explosive substance at a predetermined time delay after electric ignition of said fuse.

The invention will now be described with reference to the accompanying drawings which show embodiments of the invention by way of example and in which:

Figure 1 shows a longitudinal vieW of the device with parts in section,

Fig. l-A shows a simplied construction omitting the retaining sleeve,

Fig. l-B is another view of the simplified construction of Fig. l-A,

Fig. 1-C is a longitudinal sectional View of the tubular member or casing of the construction of Fig. 1, showing the terminal restricted bore,

Figure 2 is an exploded view showing the unit of Fig. 1 with parts in juxtaposition,

Figure 3 shows a slightly modied form of the device shown in Figure 1 applied to an appliance in the form of a liquid shut-01T cock,

Figure 4 shows another application of the device shown in Figure 1, this being shown in normal unoperated position,

'Figure 5 is a similar view to Figure 4, shown in the operated position and Figure 6 shows another modified form of device shown in Figure 1 applied to an electric switch appliance.

Referring now to Figures 1 and 2, numeral 2 denotes a tubular member having a teri minal restricted bore I2 to which the stud member 3 is secured by means of a frangible rim 4.

A closure member 5 is adapted to be inserted into member 2 to form a chamber for containing explosive substance 6, and an electrically ignitable fuse I comprising electric current heated element 44 secured in a fuse holder 8 is screwed into member 2 to secure parts 3 and 5 in appropriate position in member 2 to form a chamber for explosive 6.

Closure member 5 is provided with a longitudinal fine bore conduit 9 as shown in Figure 1.

' As shown in the construction shown in Figure 1 and Figure 2, the closure member 5 is provided with a projection I in which one or more transverse ne bored holes II are provided the eiect of which is that when fuse 'I is ignited, 4an ignition flame travels down conduit 9 and is deflected through holes II to ignite explosive substance 6 practically in the center of said substance thereby increasing the explosive effect. At the end of closure member which is opposite projection I0, ne bore conduit 9 terminates in a small conical recess which is adapted to receive fuse 'land conduct the ignition flame therefrom.

AOn occurrence of the explosion, the gaspressure passes back through holes I I of which there may be one, two or four, these holes being preferably oppositely disposed so that the gas pressure streams strike in opposite directions into conduit 9 in which they are deflected at right angles back through conduit 9, the effect of which is to reduce loss of gas pressure and thereby risk of blow back.

In order that reliability of operation shall be obtained, it has been found necessary to make rim 4 approximately .018" thick if stud 3 is of brass.

- Conduit 9 may be of the order of .030 diameter whereas holes II are generally .015 diameter, the quantity of explosive substance being between 3 to 5 grains of ne grain gunpowder.

In the simplied form of construction shown in Fig. l-A and Fig. l-B wherein the explosive substance 5 is contained between the walls of the bore of tubular member 2 and stud 3 and closure member 5, and frangible rim 4 of stud 3 is formed integrally in one piece with tubular member 2, there is risk during handling and assembly of fracturing rim 4, and for that reason the more rugged construction shown in Figure 1 is preferred and in this form of Figure 1 the member 2 is provided with a restricted bore I2 (Fig. 1-C) into which a portion of stud 3 fits reasonably tightly, rim 4 tting internally in sleeve 2 so as to retain stud 3 therein.

As shown in the form of Fig. 1, rim 4 of stud 3 and closure member 5 may be spaced from one another by a sleeve I3, this being adapted to fit into member 2, a part of the closure member 5 and the sleeve I3 being screw-threaded so as to be secured together.

In this form employing sleeve I3, rim4issecured to sleeve I3 by soldering, brazing or the like so that the parts 3, 4, 5 and I3 form a chamber for containing explosive substance 6, the unit being capable of insertion into tubular member 2, in which it is secured by metallic holder 8 of fuse "I, so that when an explosion occurs, stud 3'will be blown out by theV explosive force, rim 4 being shorn off due to its contact with the restrictedA the end of cap device 22 by a liquid excluding washer I6.

Upon electrical ignition of fuse l', stud 3 will'be blown out and plug I5 blown across the cock body plug seating I'I where it is retained by a compression spring I8 which expands to retain plug I5 in the liquid shut-oir position.

Referring to the modification of Figs. 4, 5, a I

applied to an explosive releasable spring actuated control unit, since the force which can be applied to rim 4 is limited, the tubular member 2 may be shaped in a modified form as shown at 23, Figures 4 and 5, in which case it can be secured in a housing I 9 which has a transverse portion or tube 20 integral therewith or secure thereto by welding as shown at 2|. -f'

Stud 33 (Figs. 4 and 5) is in this case elongatied compared to stud 3 of the form of Figs. 1-3, and is disposed transversely across the open space in said housing, and a s-pring urged actuatingl member 24 is disposed in the space in said housing portion or tube 20 to which it is secured by stud 33 which engages holes 25 in member 24.

By this means actuating member 24 can be displaced under action of spring 26 when explosive material 6 blows stud 33, less rim 4, into cavity 2l in housing I9 as shown in Figure 5.

As will be seen, the thrust due to spring 26 is taken by stud 33 in a transverse direction-and is not applied to rim 4, and for this reason considerably greater force can be applied to stud 33 than could be applied longitudinally to stud 3, as there would be risk of shearing the thin rim 4 if excessive force is applied to the rim.

Referring now to the modiiication of Figure 6,

applied to an electric switch, stud 3 engages anv arm 28 hinged on pin 29 which pin also supports a contact actuating member 30 which 'engagesa movable contact spring 3l adapted to opemor' close electric circuits by means .of spring contact points 32, one of which is secured to a semi-rigid spring contact 34.

As shown in Figure 6, contact points 32 are normally open and a tubular member shaped as shown at 222 engages a metallic holder 35 which encloses a delay action fuse 3S from which it is spaced by insulation sleeving 31. Y

In the particular construction Ashown in Figure 6, fuse 3S has a delay of ten seconds, 'thatis to say that when fuse 36is electrically energised it burns for ten seconds before explosive substance 6 is ignited. By this means a time vla of the switch device is obtained.

-The explosive device and the Yswitch mechanism shown in Figure 6 is enclosed in metallic or plastic materia; casing 3.8@- which fuse holder 35 is secured by bracket fand si'z'revvmeans 3 9, contacts 3l and 34 being secured to lid 40 of casing 3'8 by securing bolts, insulation Asleeving -and spacers in known manner, electrical connections 4l being taken from contacts -3l and 34 to terminals 42 in an insulation terminal block device 43 of known form.

Fuse 'l comprises yan electric current heated element 44, see Figure 2, which is connected to electric leads 45, which leads are connected to terminals 4S in a terminal block device 41 of known form.

For use in a, fire-fighting system upon aircraft, for example, the switch device appliance shown in Figure 6 may be employed to introduce a time lag between the energization of fuse 36 due to operation of a control switch which is operated on occurrence of a fire and the discharge of electrically energised fire-extinguishing appliances which are controlled by closure of switch contacts 32.

In order to provide means for checking circuit continuity over contacts 32, ian insulating cam 4S mounted upon spindle 49 is provided, said cam being operable externally from the casing and being spring operated to bring this back into normal position as shown in Figure 6.

In order to permit escape of explosive gases from c-asing 38 when closed by lid 40, a disc 5D is pressed into a recess 5| in casing 38, which disc is struck by stud 3 upon ignition of explosive substance 6 to displace the disc whereby the gases escape through an orice 52 in casing 38.

As will be appreciated, the device of the invention constitutes a form of relay, in which a small electric current generally of the order of 1/2 ampere is sufficient to eiect displacement or operation of la, mechanical device requiring considerable force, by use of a small quantity of explosive substance.

By this means the appliance of the invention has considerable advantages over electromagnetic relay and like devices which would require heavy currents for effecting operation of mechanical appliances requiring comparable force, and by this means a considerable reduction in Weight is obtained in appliances `as shown in Figures 3 to 6, which is important when these appliances are employed in fire ghting equipment for use upon aircraft.

Having thus fully described my invention, what I claim -as new and desire to protect by Letters Patent is:

1. An explosive device comprising in combination a tubular member in the form of a cap device, a stud member secured to said tubular mem- 6 ber by a frangible rim, a closuremember adapted to be inserted in said tubular member, said tubular member defining an explosive substance containing chamber between one end of said stud and said closure member, means for igniting said explosive substance to displace said stud member, a fluid cock device body, means for securing said tubular member in said body, a shut-off plug, means for securing said plug to said stud member, said fluid cock device body having a plug seating recess, and means for retaining said plug in said seating recess after displacement of said stud member by ignition of said explosive substance.

2. In an explosive actuatable valve comprising a valveseat and a bonnet, a plug, means in said bonnet for guiding' said plug into tight engagement with said valve seat, an explosive unit comprising a mounting terminal portion and a pro- `jectile terminal portion and a chamber containing explosive material interposed between said terminal portions, said projectile terminal portion being rigidly mechanically connected to said chamber only by a frangible rim, said explosive unit further comprising means for igniting said explosive material, said mounting terminal portion being iixedly mounted in said bonnet, said projectile terminal portion being rigidly mechanically connected to said plug and being directed in the direction of the path of said plug to said valve seat, whereby ignition of said explosive material fractures said frangible rim and propels said plug along said guiding means into tight engagement withsaid valve seat.

3. A valve as set forth in claim 2, said bonnet further comprising a helical spring mounted to urge said plug outwardly from said bonnet and upon projection of said projectile terminal portion to hold said plug in tight engagement with said valve seat.

4. In anrexplosive actuatable valve comprising a valve seat and a bonnet, a plug, means in said bonnet for guiding said plug into tight engagement with said valve seat, an explosive unit xedly mounted in said bonnet and comprising a sleeve, a stud member comprising a frangible rim by which it is xedly attached to one end of said sleeve, a closure member xedly attached to the other end of said sleeve, said sleeve and said stud member and said closure member dening an explosive chamber, explosive material in said chamber, said closure member comprising a bore communicating with said chamber, a fuse mounted extending into said bore, said bonnet comprising mounting means for xedly mounting said stud member and said sleeve and said closure member as a unit in said bonnet, said mounting means comprising a shoulder in engagement with said frangible rim, and a rigid direct mechanical connection between said stud member and said plug, whereby ignition of said explosive material fractures said frangible rim and propels said plug along said guiding means into tight engagement with said valve seat.

5. A valve as set forth in claim 4, said bonnet further comprising a helical spring mounted to urge said plug outwardly from said bonnet and upon projection of said stud member to hold said plug in tight engagement with said valve seat.

6. An explosive actuatable valve as set forth in claim 2, said projectile terminal portion and its said frangible rim being formed integrally with said chamber and said frangible rim constituting an integral connection between said REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 41,960 Graham Mar. 15, 1864 43,881 Graham Aug. 16, 1864 108,836 Schuler Nov. 1, 1870 387,651 Maxim Aug. 14, 1888 824,934 Jenczewsky July 3, 1906 Number 20 Number 8 Name Date Lewis Oct. 24, 1916 Lallman Sept. 25, 1917 Temple Jan. 18, 1921 Medlin Dec. 27, 1927 Baumer Nov. 18, 1930 Driggs et al. Nov. 18, 1930 Allen Oct. 18, 1932 Gillen June 13, 1933 Allen Dec. 18, 1934 Haines Nov. 24, 1936 Mathisen et al Apr. 1, 1941 Alexander July 22, 1941 Alexander July 22, 1941 Albree Nov. 25, 1941 Alexander Aug. 31, 1943 Turechek Aug. 31, 1943 FOREIGN PATENTS Country Date Germany Apr. 22, 1920

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U.S. Classification137/68.13, 251/11, 89/1.14, 251/58, 102/202.5, 137/76
International ClassificationA62C99/00
Cooperative ClassificationA62C99/009
European ClassificationA62C99/00F