US3884306A

US3884306A - Fire extinguisher

Info

Publication number: US3884306A
Application number: US414627A
Authority: US
Inventors: Robert A Williams
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-11-12
Filing date: 1973-11-12
Publication date: 1975-05-20
Anticipated expiration: 1992-05-20

Abstract

The specification discloses a fire extinguisher comprising a closed container having a fire extinguishing powder located therein. Spring means is provided for applying force to the wall of the container to form an opening or openings in the container when released by heat sensitive means in the presence of undesired temperatures. The heat sensitive means may be a fuse or firetrain which ignites at a relatively low temperature or a member which melts at a low temperature or a combination of the fuse or firetrain and the low temperature melting member. The spring means, when released, may be employed to open a removable cover or to rupture weakened portions formed in the container wall to allow the powder to be released and fall out of the container. The removable cover may be a lid which opens outward or a shutter which rotates to form the openings. The springs may be located on the exterior of the container or inside of the container.

Description

United States Patent Williams [111 3,884,306 [451 May 20, 1975 FIRE EXTINGUISHER [76] Inventor: Robert A. Williams, 55 Bounty Rd.

East, Forth Worth, Tex. 761 16 [22] Filed: Nov. 12, 1973 [21] Appl. No.: 414,627

Primary ExaminerM. Henson Wood, Jr.

Assistant Examiner-Michael Mar Attorney, Agent, or FirmWofford, Felsman, Fails & Zobal [57] ABSTRACT The specification discloses a fire extinguisher comprising a closed container having a tire extinguishing powder located therein. Spring means is provided for applying force to the wall of the container to form an opening or openings in the container when released by heat sensitive means in the presence of undesired temperatures. The heat sensitive means may be a fuse or firetrain which ignites at a relatively low temperature or a member which melts at a low temperature or a combination of the fuse or firetrain and the low temperature melting member. The spring means, when released, may be employed to open a removable cover or to rupture weakened portions formed in the container wall to allow the powder to be released and fall out of the container. The removable cover may be a lid which opens outward or a shutter which rotates to form the openings. The springs may be located on the exterior of the container or inside of the container.

12 Claims, 27 Drawing Figures PATENTEB HAY 2 01975 SHEET 10F Jay. 7

l l I m 5 4 A tr, 3 i w B 3 4 1 E W AA 5 w M w mi PATENTED 4AY201975 3 884,306

sum 2 [IF 5 PATENTED 884,306

sum 3 0F 5 PATENTED HAY 2 0 I975 SHEET 0F 5 llH'.

FIRE EXTINGUISHER SUMMARY OF THE INVENTION It is an object of the present invention to provide a safe, nonfragmenting fire extinguisher employing spring means for forming an opening or openings in a container for releasing a fire extinguishing substance from the container and which has a high factor of reliability in forming the opening or openings.

The fire extinguisher comprises a closed container having a fire extinguishing substance located in the container. In addition, there is provided spring means biased normally to apply force to at least one selected wall portion of the container to form an opening in the container when released. There is also provide heat sensitive means for holding the spring means in its normally biased position and for releasing the spring means upon sensing undesired temperatures to form an opening in the container to allow the fire extinguishing substance to pass out of the container through the opening.

The heat sensitive means may comprise an ignitable fuse or firetrain or a holding member meltable at a relatively low temperature. In a further embodiment, the fuse or firetrain is employed in combination with the holding member and melts the holding member when ignited to release the spring means.

In one embodiment, the spring means is located on the outside of the container for normally holding a cover in place and which is adapted to be moved to an open position for forming an opening in the container. The spring means is normally biased in a direction to move the cover to its open position when released. In one embodiment, the cover is adapted to move outward to form the opening, while in another embodiment, the cover is adapted to be rotated to its open position.

In a further embodiment, weakened portions are selectively formed in the wall to facilitate rupturing to form an opening in the container without fragmentation. The spring means is biased to normally apply an outward force to at least one wall portion defined by the weakened portions to rupture the weakened wall portions when released. In this embodiment, the spring means may be located on the inside of the container or on the outside of the container to rupture the container wall when released.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a fire extinguisher attached to the top of a vent-a-hood of a cooking stove;

FIG. 2 illustrates a fire extinguisher having a cover that is moved outward by a spring when released by a holding member having a low melting temperature and a fuse or firetrain to allow fire extinguishing powder to flow out of the container onto a fire;

FIG. 3 is a bottom view of the extinguisher of FIG. 2;

FIG. 4 is an enlarged cross sectional view of the spring, the holding member, and the fuse or firetrain;

FIG. 5 illustrates the ends of the spring;

FIGS. 6-12 illustrate different embodiments in which the spring may be held in place and released by a low melting temperature member, an ignitable fuse or firetrain, or a combination of the low melting temperature member and fuse or firetrain;

FIG. 13 illustrates a rotatable cover or shutter for forming openings in the fire extinguisher container;

FIG. 14 is a cross sectional view of the holding mechanism of FIG. 13;

FIG. 15 illustrates a=fire extinguisher container hav ing weakened portions which are ruptured by internal springs when released;

FIG. 16 is a bottom view of the extinguisher of FIG.

FIG. 21 is a fire extinguisher having weakened por- I tions which are ruptured by an external spring mechanism;

FIG. 22 is an end view of the fire extinguisher of FIG. 21;

FIG. 23 is an enlarged cross sectional view of FIG. 22 taken along the lines 23-23 thereof;

FIG. 24 is a fire extinguisher having weakened portions which are ruptured by another embodiment of an internal spring mechanism;

FIG. 25 is a bottom view of the fire extinguisher of FIG. 24;

FIG. 26 is an enlarged cross sectional view of FIG. 25 taken along the lines 2626 thereof; and

FIG. 27 is an alternative holding and releasing mechanism for holding and releasing the spring for forming openings in the container.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1, there is illustrated a fire extinguisher 31 attached to the top of a vent-a hood of a stove for providing protection against grease fires which may occur, for example, in a frying pan. The fire extinguisher may be located so that it is over a given burner whereby if the heat becomes too intense or flames flare up close to the fire extinguisher, a fire extinguishing substance will be released from the container onto the fire below to extinguish the fire.

Referring to FIGS. 2-5, there will be described one embodiment of the fire extinguisher which may be em ployed in the manner illustrated in FIG. 1. The fire extinguisher of FIGS. 2-4 comprises a closed container 33 formed by a cup shaped member 35 and a removable cover or lid 37 adapted to fit onto the bottom end thereof. Located within the container 33 is a fire extinguishing substance 39, preferably a fire extinguishing powder which may be of the ABC. type, or for example, of the B.C. type. As is well known, the A.B.C. type is formed of about percent monoammonium phosphate with about 10 percent silicones and other materials (silica, ground mica) added to keep it free flowing and to protect from moisture. The B.C. type is about 90-94 percent sodium bicarbonate. The balance of the material is stearates or silicones and other materials added to keep it free flowing and to protect the sodium bicarbonate from moisture.

The top end 35a of the container has an attaching mechanism coupled thereto which, in the embodiment disclosed, is a magnet 41 whereby the fire extinguisher may be attached to and hung from a metallic object, for

example, to the top of the vent-a-hood above the stove to allow the cover 37 to face downward above the burner or burners of the stove. The cover 37 normally is held in place by a spring 43 which is released to open the cover when the temperature becomes too high, for example, due to a flame resulting from a grease fire. When the cover is opened or removed, the fire extinguishing powder then will fall out of the container onto the fire. Barrier strips 45 are provided to control the flow of the powder so that it does not fall out in one lump, but allows it to gently fall out continuously for about seconds, in one embodiment. The cover 37 has edges 37a which fit against the edges 35b of the container to close the container when the cover is in place. The spring 43 has one end 43a attached to the cover 37 and its other end 43b unfolded in a direction opposite its normal coiled position and wrapped around the container where it is held by a holding arrangement comprising a washer shaped member 51 which is characterized by a low melting temperature. As seen in FIG. 5, the end 43a of the spring has an aperture 430 formed therethrough and into which is inwerted two

eyelets

53 and 55. Eyelet 53 attaches the spring end 43a to the cover while the eyelet 55 is inserted through eyelet 53 and through aperture 51a of member 51 and attaches the low melting temperature member 51 to the cover outside of the container and at a point spaced from the cover. The free end 43b of the spring is fitted under the member 51 and hence is restrained by the member 51. Also inserted through the eyelet 55 is a fuse or firetrain 57 which has a low flame temperature ignition point. In operation, a low temperature flame will ignite the fuse 57 which in turn will cause the member 51 to melt to release the free end 43b of the spring 43, which then wil coil over the top of the container and over the side of the container and up to the top of the container. Since the free end 43b of the spring 43 clears the cover 37, the other end 43a of the spring which is fastened to the cover by the way of eyelet 53 attempts to regain its shape and instantaneously removes the lid or cover 37 thereby allowing the powder 39 to fall out of the container onto the fire.

The member 51 has a very narrow temperature range between its solid and molten state and in one embodiment, has an eutectic melting temperature of 255F, eutectic meaning that it has a rather sharply defined melting temperature. The member 51 is an alloy which is commercially available and in one embodiment, has a composition of bismuth 55.5 percent and lead 44.5 percent. In another embodiment, it may have a composition of bismuth 58 percent and tin 42 percent, with a eutectic melting temperature of 281F. The fuse 57 is more susceptible to a quick flame than the member 51 and in one embodiment, may be of the type disclosed and claimed in my US. co-pending application, Ser. No. 414660, filed the same date as the present application. By employing the combination of member 51 and the flame sensitive fuse 57, the releasing mechanism is low temperature flame sensitive, as well as being temperature sensitive in that the member 51 itself will melt and release from heat alone without flame. If desired, the fuse 57 may be eliminated whereby only the holding member 51 is employed to hold and release the spring. In this embodiment, the eyelet 55 will be closoed.

The barrier 45 comprises four spaced arms extending outward within the container near the bottom end and having their base ends 45a attached to the top end 35a of the container 35 by way of a rivet illustrated at 61. On the top side of the container, a ring 63 is attached to the rivet and to a case 65 holding the magnet 41 to allow movement of the container relative to the magnet. As illustrated, the ring 63 extends through aperture 61a formed through the exterior end of the rivet 61 and through aperture 67 extending through the exterior end of a rivet 69 attached to the magnet case 65. If desired,

the magnet may be removed to allow the fire extinguisher to be attached with nails or staples to a wooden member by way of the ring 63. In this embodiment, the fire extinguisher may be attached and hung from the rafters of a roof for fire protection purposes.

In one embodiment, the spring 43 is a stainless steel continuously pre-formed spring, pre-formed to a continuous diameter of 0.375 which tends to coil upon itself when released. As shown in FIG. 4, a light coating 71 of nitrocellulose may be applied around the fuse 57 on the interior side of the cover 37 to enhance burning. The container 33 comprising member 35 and cover 37 are formed of aluminum. There is no water-proof seal between the cover 37 and member 35 except during shipping or storage which is accomplished by a pull-tab shrink sleeve 73. When the tire extinguisher is to be employed for protection against fire, the sleeve 73 will be pulled off before the fire extinguisher is mounted in place to allow the fire extinguisher to function as intended.

As disclosed in my co-pending application, the fuse disclosed and claimed therein comprises a thin copper wire heavily coated with a fast burning substance or material which contains, in essence, 2 3 micron size fine silicon powder for fuel ranging from 30 to 60 percent, and lead peroxide (PbO ranging from 30 to 60 percent as an oxidizer plus. 5 to 10 percent fine zinc powder to add to the heat of the burning and acetone wetted cellulose nitrate used to bind these materials together. The ratios of this formulation may be varied to produce different burning rates and this formulation is extremely stable. Wrapped around the fast burning substance is a protective covering comprising spirally wrapped wires which may be formed of glavanized soft iron. Spirally wrapped around the wires in a counter direction is a nylon yarn. Deposited on the yarn, and hence on the cover is a coating of nitrocellulose for environmental protection and which also provides high flammability. The purpose of the inner copper wire is to provide support for the fuse and continuity of burning since it has a high thermal conductivity. The fast burning substance around the copper wire enables the fuse to burn rapidly. The cover comprising the spirally wrapped wire and yarn prevent the fuse from being extinguished or destroyed in its burning process. The purpose of the outer coating of nitrocellulose is for environmental protection and also provides a high flammability as indicated above. The ends of the fuse are cut at an oblique angle of about 45 relative to the axis of the fuse to provide a sharp pointed tip to allow the highly flammable outer coating, which is also applied to the cut ends, to ignite easily and to provide a large surface on the ends to facilitate burning of the highly flammable coating whereby the fuse may be ignited readily by a low temperature flame.

Referring now to FIGS. 6-12, there will be described different ways in which the spring 43 may be held in place for confining the cover 37. In the embodiment of FIGS. 6 and 7, the'end 43a of the spring is secured to the cover 37 by way of a rivet 81. The tips of both ends of the spring 43 have

apertures

83 and 85 extending therethrough. A wire strand 87 may be formed of a low temperature melting alloy mentioned above or it may be a wire fuse, for example, of the type known as Pyro- Fuse. This fuse also may be ignited by a low temperature flame. It is available in strand or wire form and is bi-metallic having an outer shell formed of palladium and an inner core of aluminum. It is manufactured by Pyro-Fuze Corporation, an affiliate of Sigmun Cohn Corporation, 121 S. Columbus Ave., Mount Vernon, NY. 10553.

In the embodiment of FIGS. 8 and 9, the end 43a of the spring 43 is secured to the cover 37 in the same manner as shown in FIG. 4, however, the low melting temperature member 51 is elongated and has an aperture 91 formed in its extending end and the spring end 43b has a narrowed end 92 inserted through the aperture 91.

In the embodiments of FIGS. -12, the spring end 43a is secured to the cover 37 by way of a rivet 81. Both ends 43a and 43b are narrowed and are inserted through

apertures

93 and 94 formed through a low melting temperature member 95. If desired, a U-shaped fuse 96 which is low temperature flame sensitive may be inserted through

apertures

97 and 98 formed through member 95. The fuse 96 may be of the type disclosed and claimed in my co-pending application mentioned above.

Referring now to FIGS. 13 and 14, the cover employed is a rotatable shutter 101 which is pivotally coupled for rotation to the end wall 103 secured to the container sides 35 by a water-proof double seam. The container wall 103 has three openings 105-107 shown in dotted lines while the shutter 101 has three openings 115-117. In FIG. 13, the shutter 10] is shown in its closed position whereby portions 118-120 of the shutter overlay and close the openings 105-106, formed in the wall 103. The shutter is adapted to be rotated clockwise to align openings 115-117 with openings 105-106 to allow the fire extinguishing powder to fall out of the container. In the open position, the sections of the wall 103 and of the shutter 101 between the aligned openings control the flow of the fire extinguishing powder from the container to allow it to gently fall out for a period, in one embodiment,, of about 10 secends.

The shutter 101 is pivotally coupled to the wall 103 by way of a rivet 121 which is inserted through an eyelet 123. Also located around the rivet 121 is a sleeve 125 around which is located a coil spring 127 shown under tension in FIG. 13. One end 127a of the spring 127 is secured to a rivet 129 which in turn is secured to the wall 103. The rivet 129 extends through opening 115 of shutter 101. The other end 12712 of the spring 127 is secured to a rivet 131 which in turn is secured to the shutter 101. A low melting temperature member 133 is secured to the tops ends of the two

rivets

129 and 131 for restraining the spring and hence holding the shutter 101 in its closed position. Extending through two apertures formed in member 133 is a U- shaped fuse 135 which is low flame temperature sensitive. This fuse may be the same as fuse 96 described with respect to the embodiment of FIGS. 10-12. In operation, when the fuse 135 is ignited, the member 133 melts to release the spring 127. When this occurs, the spring end 127b will expand clockwise to rotate the shutter 101 clockwise to align apertures 115-117 respectively with apertures 105-107. If desired, the fuse 135 may not be employed.

Referring now to FIGS. 15-20, the container 33 has an end wall 141 secured to its sides 35, by a waterproof double seam. Formed in the wall 141 are scored lines or weakened portions 143-146 which may be ruptured by applying force to the wall portions 153-156 to form openings through the wall 141 to allow the fire extinguishing powder to pass outward. Located within the container 33 are four spring members 161, each of which is similar in shape to a safety pin. Each spring 161 has one end 161a held in place by a square ferrule 165 and a hat shaped member 167. As illustrated, the member 167 has groove 169 formed therein into which are inserted the ends 16111 of the springs. The ferrule 165 then is slipped over the member 167 with the springs in place and the tabs 171 wrapped onto the base of the ferrule 165 to secure the springs in place. The other ends 161b of the springs 161 engage the pointed ends of the tear-

open sections

153, 154, 155, and 156 to normally apply an outward force against these sections. Extending through the bottom of the member 167 are inner and

outer eyelets

173 and 175. The outer eyelet 175 secures the hat shaped member 167 to the container end 141 while the inner eyelet 173 secures a low melting temperature member 177 against a washer 179 to hold the washer 179 against the exterior of the wall 141. As illustrated, the peripheral edges of the washer 179 extends over the tips or pointed ends of the tearout sections 153-156. Thus, as long as the low melting temperature member 177 holds the washer 179 in place, the springs 161 are prevented from rupturing the weakened portions defining the sections 153-156. Extending through the inner eyelet 173 is a low temperature flame ignitable fuse 57 as described previously. The low temperature melting member 177 may be the same low temperature alloy as described previously. In operation, when the fuse 57 ignites, it will cause the member 177 to melt thereby releasing the restraining force against the washer 179, whereby the washer 179 is free to move outward. When this occurs, the force of the springs 161 is released thereby causing the spring arms 16111 to expand outward thereby rupturing the weakened portions 143-146 and hence causing the tear-out portions 153-156 to be forced outward, without fragmentation, to form openings in the wall 141 to allow the fire extinguishing powder to drop outward onto a fire below. Preferably the container member 35 and wall 141 will be formed of aluminum. It is to be understood that the low melting temperature member 177 is sensitive to heat as indicated above and will melt when the temperature becomes sufficient even though there is no flame sufficient to ignite fuse 57. In addition, if desired, the fuse 57 may be eliminated. In this instance, the eyelet 173 employed will be a plugged eyelet.

Referring now to FIGS. 21-23, there will be described an embodiment wherein springs are located on the exterior of the container for rupturing wall portions defined by weakened portions or grooves for forming openings in the container. In FIG. 22, the spring assembly is identified at 201 and comprises a spring plate having four spring sections 203-206 with parallel sides and pointed ends extending inward within the heart shaped cutout sections 207-210. The outer edge of the assembly 201 is attached by rivets 211 to the exterior side of the container wall 212 which is sealed to the container member 35 by a water-proof double seam. The central portion of the spring assembly 201 is at- '7. d tached to the container wall 212 by way of an eyelet 217. Formed in the wall 212 of the container are tearout or rupturable sections formed by weakened or grooved-lines in the wall 212 which correspond with the patterns of the heart shaped cutout sections 207-210. In'FIG. 23, the grooved lines forming these pull out sections are.illustrated at 219. The inner against a washer 227. Fuse 229 extends through eyelet 223. The peripheral edges of the washer 227 overlays the pointed ends of the spring members 203-206 and prevents the spring members from moving outward as long as the member 225 and washer 227 are in place. Normally the spring members 203 will be formed so that they will be biased in an outward direction against the pointed ends of the tear-out portions 233-236.

Thus the member 225 and washer 227 normally prevent the springs 203-206 from rupturing the weakened portions of the wall 212. When the fuse 229 ignites, the

2 member 225 melts whereby releasing the washer 227.

-When this occurs, the force of the springs 203-206 is sufficient to rupture the weakened or scored portions thereby pulling the tear-out sections of the wall 212 outward to formopenings in the wall to'allow the fire extinguishing powder to escape.

The holding and releasing mechanism for holding the spring members in place comprise aninner eyelet 223 inserted within eyelet 217 and which holds a low melting temperature member 225 against a washer 227. As

being pulled outward when the washer is in place. Ex-j tending through the inner eyelet'217 is a low temperature flame sensitive fuse 229. The fuse 229 may be the same as fuse 57 described in the embodiments of FIGS.

1-5, while the washer 225 may be'the same as washer 51 described in the embodiment of FIGS. l-5. In operation, when the fuse 229 ignites, the member 225 melts thereby releasing the washer 227 and allowing the springs 203-206-to spring outward and rupture the weakened portions of'the wall 212 thereby pulling the tear-out sections outward to form the desired openings. In FIG. 21, three tear-out sections pulled outward by

springs

204, 205, and 206 are illustrated a234,- 235, and 236. It is noted that when the tear-out sections-are pulled outward, their outer ends remain connectedlto the container wall 212. g Y

As illustrated in FIG. 23,. the washer 217 also clamps an internal spring washer 237 against the inside'heads of the rivets 221.. The purpose of the internal spring washer 237 is to apply additional loading against the rivets 221 to start the'tearing action of'the tear-out sections from the wall 212 when the member 225 melts and the washer 227 is released. In FIG. 23, a thin coating 239 of nitrocellulose is applied around the fuse on the inside of the container to facilitate burning and ignition.

Referring now to FIGS. 24-26, an internal spring is employed for rupturing weakened or scored lines of the wall and forcing tear-out sections outward to form the desired openings in the container. The spring assembly is identified at 201 in FIG. 24 and has the same shape as that illustrated in FIG. 22, however, it is attached to the inside of the wall 212 which is illustrated in FIG. 25 and has the same shape and form as the wall 212 of FIGS. 21-23. The wall 212 is attached to the sides of the container by a water-proof double seam. The outer edge of the spring assembly 201 is attached to the inside of the wall 212 by rivets illustrated at 211. Eyelet 217 attaches the central portion of the spring assembly to the wall 212 as illustrated in FIG. 26 while eyelet 223 holds the low temperature melting member 225 of the wall thereby forcing the tear-out sections 233-236 outward to form the desired openings to allow the fire extinguishing powder to pass outward.

FIG. 27 illustrates an arrangement for holding the springs 203-206 in place and then releasing the springs without the use of the fuse 229. In this embodiment, in-

stead of eyelet 223, a semi-tubular rivet 243 is employed to secure a multipointed low melting temperature member 245 against the washer 227 to prevent the force of the springs 203-206 from rupturing the scored portions and forcing the tear-out sections outward. When the member 245 melts, the washer 227 will be released to allow the springs 203-206 to rupture the scored portions and force the tear-out sections outward to form the desired openings. It is to be understood, that the rivet 243 and low temperature melting member may be employed in the embodiments of FIGS. 24-26 in lieu 'of the eyelet 223 and fuse 229.

In the embodiment of FIGS. 24-27, the tear out

sections

233, 234, 235, and 236 may be removed thereby forming openings in the wall 212. The openings will be I covered by a thin and breakable circular disc located on the inside of the wall 212. The pointed ends of the springs 203-206 will bear against the'disc at points opposite the washer 227. When the fuse 229 ignites and the member 225 melts and the washer 227 is released, the force of the springs will rupture the disc through the openings thereby allowing the powder to fall out of the container onto the tire below. In one embodiment, the breakable disc may be formed of aluminum foil.

I claim 1. A fire extinguisher comprising:

a closed container,

a fire extinguisher substance located in said container,

spring means biased normally to apply force to at least one selected wall portion of said container to form an opening in said container when its force is released,

a meltable holding member for normally holding said spring means in its normally biased position and for releasing said spring means when said holding member melts, and

a heat sensitive fuse or firetrain adapted to ignite in the presence of temperature of a given intensity to apply heat to said holding member to allow'said member to melt and release said spring means to form an opening in said container to allow said fire extinguishing substance to pass out of said container through said opening.

2. The fire extinguisher of claim 1 wherein said spring means is located on the outside of said container.

3. The tire extinguisher of claim 2 wherein: Y

said selected wall portion comprises a cover adapted to be moved to open and closed positions for forming said opening and for closing said container,

said spring means being normally biased in a direction to move said cover to its open position when said spring means is released.

4. The fire extinguisher of claim 3 wherein said cover is adapted to move outward to form said opening.

5. The fire extinguisher of claim 4 wherein said spring means has one end held by said holding member and is wraped around said container and has its other end attached to said cover.

6. The fire extinguisher of claim 3 wherein said cover is adapted to be rotated to its open position.

7. The fire extinguisher of claim 6 wherein said spring means has one end coupled to a stationary wall portion of said container and its other end coupled to said cover for rotating said cover to its open position.

8. The fire extinguisher of claim 2 wherein:

said selected wall portion is formed by weakened wall portions selectively formed to facilitate rupturing to form an opening in said container without fragmentation,

said spring means is biased to normally apply an outward force to said selected wall portion to rupture said weakened wall portions when said holding member melts to form said opening in said container.

9. The fire extinguisher of claim 1 wherein said spring means is located on the inside of said container.

10. The fire extinguisher of claim 9 wherein:

said selected wall portion is formed by weakened wall 10 portions selectively formed to facilitate rupturing to form an opening in said container without fragmentation,

11. A fire extinguisher comprising:

a closed container,

a fire extinguishing substance located in said container,

force producing means biased normally to apply force to at least one selected wall portion of said container to form an opening in said container when its force is released,

a meltable holding member for normally holding said force producing means in its normally biased position and for releasing said force producing means when said holding member melts to form an opening in said container to allow said fire extinguishing substance to pass out of said container through said opening, and

a heat sensitive fuse or firetrain adapted to ignite in the presence of temperature of a given intensity to apply heat to said holding member to allow said holding member to melt to release said force producing means.

12. The fire extinguisher of claim 11 wherein said holding member is characterized by a narrow temperature range between its solid and molten state.

Claims

1. A fire extinguisher comprising: a closed container, a fire extinguisher substance located in said container, spring means biased normally to apply force to at least one selected wall portion of said container to form an opening in said container when its force is released, a meltable holding member for normally holding said spring means in its normally biased position and for releasing said spring means when said holding member melts, and a heat sensitive fuse or firetrain adapted to ignite in the presence of temperature of a given intensity to apply heat to said holding member to allow said member to melt and release said spring means to form an opening in said container to allow said fire extinguishing substance to pass out of said container through said opening.

3. The fire extinguisher of claim 2 wherein: said selected wall portion comprises a cover adapted to be moved to open and closed positions for forming said opening and for closing said container, said spring means being normally biased in a direction to move said cover to its open position when said spring means is released.

8. The fire extinguisher of claim 2 wherein: said selected wall portion is formed by weakened wall portions selectively formed to facilitate rupturing to form an opening in said container without fragmentation, said spring means is biased to normally apply an outward force to said selected wall portion to rupture said weakened wall portions when said holding member melts to form said opening in said container.

10. The fire extinguisher of claim 9 wherein: said selected wall portion is formed by weakened wall portions selectively formed to facilitate rupturing to form an opening in said container without fragmentation, said spring means is biased to normally apply an outward force to said selected wall portion to rupture said weakened wall portions when said holding member melts to form said opening in said container.

11. A fire extinguisher comprising: a closed container, a fire extinguishing substance located in said container, force producing means biased normally to apply force to at least one selected wall portion of said container to form an opening in said container when its force is released, a meltable holding member for normally holding said force producing means in its normally biased position and for releasing said force producing means when said holding member melts to form an opening in said container to allow said fire extinguishing substance to pass out of said container through said opening, and a heat sensitive fuse or firetrain adapted to ignite in the presence of temperature of a given intensity to apply heat to said holding member to allow said holding member to melt to release said force producing means.