US3369609A

US3369609A - Fire extinguishing apparatus

Info

Publication number: US3369609A
Application number: US543465A
Authority: US
Inventors: John E Fogelgren
Original assignee: G L IND
Current assignee: G L IND
Priority date: 1966-03-18
Filing date: 1966-03-18
Publication date: 1968-02-20
Anticipated expiration: 1985-02-20

Description

Feb. 20, 1968 J. E. FOGELGREN 3, 9

FIRE EXTINGUISHING APPARATUS Filed March 18, 1966 6 Sheets-Sheet l INVENTOR J 0 IVA/E E651 GPE V ATTORNEYS 1968 .J. E. FOGELGREN 3,369,609

FIRE EXTINGUISHING APPARATUS Filed March 18, 1966 6 Sheets-$heet 2 INVENTOR Jaw/v5 P06616186 Feb. 20, 1968 J. E. FOGELGREN FIRE EXTINGUISHING APPARATUS 6 Sheets-Sheet 5 Filed March 18, 1966 fi/VE E6152 GEE/Y Feb. 20, 1958 J, v FOGELGREN 3,369,609

FIRE EXTINGUISHING APPARATUS Filed March 18, 1966 6 Sheets-Sheet 4 ATTORNEYS 1968 .1. E. FOGELGREN 3,369,609

FIRE EXTINGUISHING APPARATUS Filed March 18, 1966 6 Sheets-Sheet 5 IN VEN TOR. F2654 war/v Feb. 20, 1968 J. E. FOGELGREN 3,369,609

FIRE EXTINGUISHING APPARATUS Filed March 18, 1966 6 Sheets-Sheet 6 INVENTOR.

Ja/M/E', Ffoaax sway i I? .77 0/94 6 Y3 3,369,609 FIRE EXTINGUISHING APPARATUS .Iohn E. Fogelgren, Rockville, Md, assignor to G-L Industries, Westville, N.J., a corporation of New Jersey Continuation-impart of application Ser. No. 446,887, Apr. 9, 1965. This application Mar. 18, 1966, Ser. No. 543,465

16 Claims. (Cl. 169-31) This invention relates to a projectile fire extinguishing grenade and a gun for accurately projecting the same.

This application is a continuation in part of application Ser. No. 446,887, filed Apr. 9, 1965, now abandoned.

In many instances of fighting fires, it is desired that the fireman remain a safe distance from the fire while accurately distributing a fireextinguishing material upon States Patent the 'fire. Such instances include fighting fires in hazardous storage areas (containing explosives, chemicals or highly inflammable materials), boats and other dangerous or inaccessible areas and gasoline and oil spill fires. It has also been desired to place a fire-extinguishing material upon a fire which is located behind drywall walls or ceilings, panelled doors, or windows. Water and most other liquids have been unacceptable for extinguishing such fires as gasoline fires and electrical fires. Free flowing fire extinguishing chemicals, such as potassium bicarbonate, can be used on almost any type of fire. However, until the present invention, no means were known for accurately directing free flowing fire extenguishing chemicals upon large fires from a safe distance, for instance, over 50 feet away, in sufiicient volume to extinguish or seriously retard the fires, or to direct fire extinguishing chemicals upon fires behind drywall walls and ceilings or panelled doors.

It is an object of this invention to provide a compressed gas-operated device to project free flowing fire extinguishing chemical grenades upon fires from a safe distance with rapidity and accuracy.

It is an additional object of this invention to provide a device which uses differential piston areas exposed to fluid pressure for both the triggering or valve operation and the propelling of a fire extinguishing projectile.

It is another object of this invention to provide a compressed gas-operated device to project grenades, or containers, from one point to a second, predetermined point, which may be appreciable distance from the first point, with rapidity and accuracy.

It is a further object of this invention to provide a free flowing fire extinguishing chemical grenade with a gasoperated time delay fuse. Still further objectives and the entire scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description, while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes or modifications within the scope of the invention will become apparent to those skilled in the art from this detailed description.

Briefly, the invention in part consists of a gun which contains two compressed gas chambers. Operation of a trigger releases the gas pressure in the rear chamber which causes differential piston areas exposed to the front chamber gas pressure to operate valves which release the compressed gas in the front chamber and direct the released gas upon the rear face of a grenade contained within the tube of the gun to propel the grenade from the gun toward a fire or other target. At the same time that the valves are operated, the valve stem delivers an impact to an arming device on the grenade. The invention also consists of an associated grenade which contains free flownig fire extinguishing chemicals and a compressed gas cartridge which operates a time delay fuse. The impact from the guns valve stem causes a plunger to puncture the gas cartridge. The compressed gas operates a time delay fuse device which, after a predetermined period of time, releases the contained gas to the inside of the grenade. The sudden gas pressure thus released causes the grenade casting to split, dispersing the fire extinguishing powder charge in a cloud which blankets the target area.

The invention will be more clearly understood from the drawings, in which:

FIGURE 1 is a view of the compressed-gas operated, fire extinguishing grenade projecting gun;

FIGURE 2 is a side view, partly in section, of the gun of FIGURE 1;

FIGURE 3 is a sectional view of the gun of FIGURE 2, taken along lines 33;

FIGURE 4 is a view of an embodiment of the gun of FIGURE 1, where a four-tube magazine is provided on the gun;

FIGURE 5 is a side view, partly in section, of the gun of FIGURE 4, showing the magazine rotator;

FIGURE 6 is a sectional view of the gun of FIGURE I 5, taken along lines 6-6;

FIGURE 7 is a side view in section of the fire extinguishing grenade;

FIGURE 8 is a partial section of the grenade of FIG- URE 7, showing a modification of the time fuse;

FIGURE 9 is a side view, partly in section, of the grenade of FIGURE 7, modified for hand arming and throwing;

FIGURE 10 is a side view, partly in section, of an embodiment of the gun of FIGURE 2, wherein the valve and valve seat have been modified and a valve guide is used;

FIGURE 11 is a sectional view of the valve and valve guide of FIGURE 10;

FIGURE 12 is an end view of the valve guide of FIG- URE 10;

FIGURE 13 is a side view in section of the grenade of FIGURE 7, showing a modification of the time fuse;

FIGURE 14 is a side view in section of the grenade of FIGURE 7, showing yet another modification of the time fuse;

FIGURE 15 is a sectional view of the rear piston 141 of FIGURE 14, taken along line 1515;

FIGURE 16 is a sectional view of the front piston 140 of FIGURE 14, taken along line 16-16; and

FIGURE 17 is a side view in section of the grenade of FIGURE 14, showing an additional embodiment of the modified time fuse and also a modification of the arming mechanism.

In FIGURE 1, the gun consists of a stock assembly 101, a rear receiver 102, a front receiver 103, pressure chamber tube 104, a barrel 105, a front handle 106, a rzar handle 107, a trigger 108 and an air t-ube coupling 1 9.

In FIGURE 2, the propelling means of gun 200 consists of two

chambers

102 and 202 which may contain pressurized gas. These two chambers are separated by wall 203 and connected by one-way ball check valve 204 located in wall 203' Running through

chambers

201 and 202 and wall 203 is valve stem 205. The front of valve stem 205 is attached to front valve 206 while the rear of the valve stem is connected to rear valve 207. When closed, front valve 206 seats on seat 208, which is part of front receiver 103. Extending forward of front receiver 103 is barrel 105, which is shown holding a grenade 211. The front of front valve 206 carries a rod-like extension 212, so arranged that it strikes the rear of grenade 211 when the gun is fired. Attached to the bottom of front receiver 103 is front grip 106.

The front pressure chamber 201 is defined by front valve 206 and valve seat 208, pressure chamber tube wall 104 and wall 203.

Wall 203 is part of rear receiver 102. Wall 203,. rear receiver 102 and rear valve 207 define rear chamber 202. Spring 216 which seats in a recess in Wall 203 is biased to exert a pressure on valve 207 to keep valve 207 seated on valve seat 237 except when the gun is fired. A sleeve 245 on the part of rear wall 203 extending forward'of' the recess serves as a support and guide for valve stem 205. Valve seat 237 is part of rear housing .218. This a housing is held in place on receiver215 by retaining ring 219, and is sealed by O-ring 220.

The chamber 221 defined by rear valve 207 and 'housing 218 is 'open to the atmosphere through ports (better seen in FIGURE 3) in housing 218. Housing 218 also contains a sleeve portion 222 in which a rearward rodlike extension 242 of valve 207 rides. This sleeve 222 is fitted with a safety lock assembly 238. Stock assembly 101 is fitted to sleeve 222.

Port 223 is contained in rear receiver 102 and opens into rear pressure chamber 202. Balanced spool valve 224 is located in port 240 between port 223 and tube 225, which connects to a source of compressed gas (not shown) by quick-disconnectcoupling 109. Tube 225 is enclosed by rear grip 107.

Balanced spool valve 224 consists of a spool and associated O-

rings

228, 229, and 230. These three O-rings must be approximately the same size. The portion 231 of the spool between O-

rings

229 and 230 is of reduced diameter. The rear portion 235 of port 240 is of enlarged diameter and opens to the atmosphere. The front of spool valve 224 is connected to trigger 108, which is protected by trigger guard 233.

When the trigger 108 is at its rearmost or firing position, as illustrated in FIGURE 2, the flow of air from tube 225 is blocked by portion 234 of the spool valve 224. This. portion 234 is sealed by O-

rings

228 and 229. At the same time, port 223 can discharge around the reduced area 231 'of the spool, which area is open to the atmosphere as O-ring 230 is smaller than the diameter of the enlarged portion 235 of port 240.

When the trigger 108 is at the mid-point of its horizontal movement, the flow of gas from tube 225 is still blocked by O-

rings

228 and 229. O-ring 230 is engaged with the interior surface of port 240 at the area designated 236, and, together with O-ring 229, blocks the discharge of gas from port 223.

When the trigger 108 is at its forward or charging position, O-ring 229 has moved past the entrance of tube 225 while O-ring .230 is still in the area 236 to seal the contained gas from the atmosphere. Gas can then pass through tube .225, through the space between spool portion 231 and the wall of port 240, and into rear chamber 202 through port 223.

As previously mentioned, the O-

rings

228, 229 and 230 are of equal size. Since they are of such equal size, gas contained between any two of the rings exerts an equal pressure on each ring. Since the pressures are equal, spool valve 24, is not biased in either direction in which it could travel and consequently is termed a balanced valve.

It is essential for the operation of the present invention that the front valve 206 have a smaller surface area exposed to internal gaseous pressure than rear valve 207 and preferably front valve 206 is of significantly smaller exposed surface area. This requirement can readily be appreciated from the following description of the operation of the gun.

In the charging operation, when the coupling 109 is connected to a source of compressed gas and an associated regulator, set, for example, to deliver 150 psi. air, and the trigger 108 is pushed all the way forward, gas flows from the source, through the regulator, through tube 225, and through the space between the reduced portion 231 of the spool 224 and the interior wall of port 240. While flowing around the spool area 231, the

4, gas is sealed against escape by O-

rings

230 and 229. The

gas then passes into rear pressure chamber 202 by way ofport 223. Valve 207, which is lightly held in positionon valve seat 237 by spring 216, is firmly seated on the seat by the gas pressure exerted on its face. At the same time, ball 241 in one-way ball check valve 204 is pushed forward, allowing the gas to pass into forward pressure chamber 201. Front valve 206 is seated on front valve seat 208 by the force exerted on rear valve 207 and transmitted by valve stem 205. The gas presure in front chamber 201 builds up until it is equal to the pressure in rear chamber 202. Because rear valve 207 has a greater surface area exposed to the gas pressure than front valve 206, and because the pressures in the two chambers are equal, the valves are held firmly shut by the gas pressure operating on the differential areas to produce a resultant force tending to move the whole valve assembly to the rear.

In firing the gun, the trigger is pulled to its rearmost position. Spool valve section 234, with associated O-rings 228and 229, blocks the passage of gas flow from tube 225. Since O-ring 230 has been moved into the enlarged area 235 of port 240, port 223 can, discharge the gasin rear chamber 202 to the atmosphere. As the pressure in rear chamber 202 drops, ball 241 in one-way ball check valve 204 is moved to its rearward position, blocking flow from chamber 201 to chamber 202. Thus front pressure chamber 201 retains its charged pressure, for example, psi. pressure, While rear pressure chamber 202 is discharging gas to the atmosphere and dropping in pressure. As rear chamber 202 loses its pressure, the point is reached where the total force (pressure times area) exerted pushing valve 206 forward is greater than the force which pushes valve 207 rearward. At that time the valve system (front valve 206, valve stem 205, and rear valve 207) moves forward. As soon as rear valve 207 is clear of rear valve seat 237, the gas remaining in rear chamber valves and slams the valve system forward. The gas con tained in front pressure chamber 201 then rushes past valve seat 208 and exhausts through muzzle 105, propelling grenade 211 to the target. The valve system initially is moving faster than the grenade 211 and the front rod-like extension 212 strikes a plunger in the base of grenade 211. As will be explained, this blow starts the time-delay fuse in the grenade into operation.

The one-way ball check valve 204 may be replaced with any equivalent positive one-way flow regulator. However, the ball check valve is preferred as it gives more reliable performance than equivalents such as flap valves.

FIGURE 3 is a cross-section of the gun 200'taken along line 3-3 whichpasses through the safety lock assembly. Rear receiver 102 surrounds rear housing 218. Ports 301 pass through rear housing 218. Rear housing 218 has a sleeve portion 222 extending to its rear. The sleeve portion 222 is fitted with a safety lock assembly 238 which locks extension 242 of the rear valve. The safety lock assembly consists of a locking pin 302 which contains grooves 303 and 304. Spring-biased detent 307 is held in bore 306'.

When the locking pin is pushed to the left as far as it will travel (as illustrated in FIGURE 3), detent 307 engages groove 303 to hold pin 302 in place. The enlarged portion 308 of thepin engages a groove cut into the extension 242 of therear valve, and so locks the extension.

When the locking pin is pushed to the right, detent 307 engages groove 304 and holds the pin in position. The reduced portion 309 of the pin is then over the groove cut into the extension 242 of the rear valve but does not cugage it and the gun may be fired.

A modification of front valve 206 is shown in FIG- URE 10. Front valve seat 2008 has a tapered seating surface. Front valve 2006 is also tapered. By using tapered valves and valve seats, the front valve opens easier, seats in a more positive manner, and allows a reduction in the force exerted by spring 216.

Valve guide 1001 is firmly attached by means of bolts 1002 to the back of front valve 2006. This valve guide 1001 reduces whip in valve stem 205. Valve guide 1001 rides on the innermost portion of front valve seat 2008, thereby reducing vibration and whip of front valve 2006 when the valve is unseated. Extension 2012 is attached to the front end of valve stem 205. This extension 2012, which functions in the same manner as rod-like extension 212 of FIGURE 2, strikes the rear of a grenade contained within barrel 105 when the gun is fired.

FIGURE 11 is a side view in section of valve 2006 and valve guide 1001, which are attached by means of bolts 1002. Valve guide 1001 has 4 ribs 112 and an annular ring 114. Valve guide 1001 contains an inner bore 111 which may be essentially the same diameter as valve stem 205 or may be of larger diameter as shown.

FIGURE 12 is an end view of the valve guide 1001 of FIGURES l and 11. This valve guide 1001 has 4 ribs 112, an annular ring 114 and 2 bores 120, for receiving the bolts 1002 of FIGURES l0 and 11.

While it is readily appreciated that many various materials may be used in the manufacture of the various parts of the gun, plastics, and in particular high impact polyethylene and ABS, because of their high strength and low weight, have proved particularly desirable.

Since it has been found desirable to place as many fire extinguishing grenades on a fire in as short of a time period as possible, the preferred embodiment of the fire extinguishing grenade gun is shown in FIGURE 4 as gun 400. The gun of FIGURE 1 has been modified by the inclusion of a 4-tube magazine 401.

FIGURE 5 is a side view of the magazine gun 400, shown partly in section. Four tubes 501 are mounted on tube receiver 502. Sleeve 503 is also mounted on tube receiver 502 in bore 504 and is located parallel to and central of the tubes 501. The magazine (consisting of the four tubes 501, tube receiver 502, and sleeve 503) is mounted on the gun by means of spindle 505.

Housing 506 is mounted on front receiver 103 of the gun. Housing 506 is split into several parts for ease of assembly of the magazine rotator, and the parts are bolted together. Bearing 507 and flanged bearing 508 support spindle 505 and allow it to rotate freely in the housing. Lock nut and washer 510 hold spindle 505 in housing 506. Plunger 509 is freely, axially mounted in spindle 505 and has cap 511 mounted on its rear end. Spring 5112 biases cap 511 to the rear. Two spindle latches 513 are pivotally mounted on the front end of spindle 505 by pins 514. The spindle latches 513 have fingers 515 which ride in a groove 5116 cut into the end of the plunger. The spindle is keyed by means of pin 517 (shown dashed) to tube receiver 502. Ratchet 518, which is more clearly seen in FIGURE 6, is keyed by key 519 to spindle 505. Ball plunger 520 acts as a detent for ratchet 518.

U-shaped gasket 521 seals the gap between the front receiver and the tube receiver 502. The gas pressure in the firing operation of the gun causes the front face of gasket 521 to firmly engage the tube receiver and seal the gap between the gun and the magazine.

The magazine and spindle assembly shown permit rapid interchange of magazines on the gun. Spinde latches 513 and spindle 505 easily slip into bore 504 and sleeve 503. When fully inserted, the spindle latches 513 open and engage the front end of sleeve 503. Spring 512 pushes plunger 509 toward the rear and the groove 516 in the plunger pulls spindle latch fingers 515 rearward with it. As the spindle latch fingers move rearward, spindle latches 513 pivot about pins 514 to throw the rear ends of the spindle latches outward to engage sleeve 503 (as shown in FIGURE 5). The magazine is then held firmly on the gun. When cap 511 is pushed forward, the rear shoulder of groove 516 in plunger 509 pushes the spindle latch fingers 515 forward, and thus causes the rear ends of the spindle latches to move inward and disengage sleeve 503. The magazine assembly 401 is then free to slip off of the spindle 505 and be removed from the gun.

FIGURE 6 is a cross-section of the rotator assembly of FIGURE 5, taken along lines 6-6. Port 601 in housing 506 connects front pressure chamber 201 and a channel (not shown) in gasket 602 which is held on housing 506 by cover plate 603. The channel opens into the area between cover plate 603 and piston 604. Piston 604 is located in bore 605 in housing 506, and seals against the walls of bore 605 by means of O-ring 606. Connecting rod holder 607 fits into piston 604. Spring 608 biases connecting rod holder 607 and piston 604 toward cover plate 603.

Connecting rod 609 is held by connecting rod holder 607 inside of spring 608fThis connecting rod is shown in FIGURE 6 in the position it would be in when the gun has been fired. The connecting rod is also shown dashed in FIGURE 6 in the position it would be in when the gun has been charged.

In operation, piston 604 is held by spring 608 against gasket 602 when the gun is uncharged. Spring 608 also holds connecting rod holder 607 against piston 604. Connecting rod 609 is attached to connecting rod holder 607 and travels toward cover 603 along with piston 604 and connecting rod holder 607. Since connecting rod 609 is spring loaded, it has a tendency to drop down toward front receiver 103. Magazine 401 is then free to rotate, along with spindle 505 and ratchet 518, held only by ball plunger detent 520.

When the front pressure chamber 201 is charged with compressed gas, a small portion of the gas passes through port 601 and the channel in gasket 602 to the area between the gasket and the face of piston 604. The force exerted on the piston face pushes the piston, connecting rod holder 607 and connecting rod 609 against the spring 608 and toward the ratchet 518. The end of the connecting rod 609 engages one of the four fingers of ratchet 518 and. rotates the ratchet (and with it, the spindle and the magazine assembly). The ratchet is rotated by the connecting rod until the connecting rod is in the dashed position of FIGURE 6. The gas pressure exerted upon piston 604- holds the connecting rod firmly in the dashed position, locking the ratchet against rotation. When the gun is fired, spring 608 returns the piston, the connecting rod holder, and the connecting rod to their original position as shown in FIGURE 6.

While at the present time it is contemplated that the compressed gas used in the gun will be under a pressure of less than 1000 p.s.i. (after passing through a pressure regulator, if such be necessary), no maximum pressure limitation upon the gun of this invention is contemplated. Parts may be made thicker, or of stronger materials, to handle any practical pressure. However, the preferred pressure range is 50-500 p.s.i.g.

In FIGURE 7, the grenade 700 is enclosed by a case 701, preferably made from rotationally moldable, fusable polyethylene powder, such as Microthene produced by US. Industries, Inc. Fuse housing 702 closes the rear of case 701 and is heat welded to the case. Lip 703 is molded onto the case 701 to retain the grenade in the barrel of the gun. Lip 703 fits into a groove in the rear of the barrel of the gun and is sheared off when the grenade is fired.

A cartridge 704 containing a compressed gas, for example, carbon dioxide or nitrogen, is fitted to the front of fuse housing 702, with the area 705 of the cartridge, designed for release of the contents of the cartridge upon puncture, facing the rear of the grenade. Inserted in axial bore 709 located in fuse housing 704 is a plunger 706 comprising a pointed end 707, a groove containing an O-ring 708,21 shoulder portion 710 and a reduced diameter portion 711. Plug 712 is located at the end of chamber 713 and serves as a guide for the reduced diameter portion 711 of plunger 706. The plug 712 has a recessed portion 714 in its outer surface. When the grenade is in a loaded, unfired condition, the end of the plunger 706 protrudes. from the recess 714 and is approximately flush with the outer face of plug 712.

Piston 715 is located on the portion 711 of plunger 706. The outer diameter of piston 715 is slightly larger than the diameter of the chamber 713, insuring a tight fit. The front face of the piston 715 is beveled to allow a measure of flexibility in the portion of the piston which contacts the walls of chamber 713. The piston 715 has an inner bore which fits tightly over the reduced diameter portion 711 of plunger 706 but is smallerthan shoulder 7100f the plunger. The piston 715 has a small port 716 extending through it. As will be readily seen when reading the descripition of the operation of the grenade time fuse, the diameter of this port will vary with the viscosity of the fluid employed in the fuse and with the time delay desired. Ports 717 connect the inner end of chamber 713 with the chamber 718 formed by case 701.

Chamber 718 is filled with a free flowing fire extinguishing chemical, such as Foray or Purple K, both dry powder fire extinguishing chemicals produced by Ansul Chemical Co. The chamber 713 between the plug 712 andthe piston 715 is filled with a fluid, preferably an incompressible, viscous silicone grease, such as Dow Corning #4. When the grenade is loaded, the piston 715 is placed as far forward on the plunger 706 as possible.

In operation, the cartridge 700 is loaded into a gun, such as represented by the numeral 200 inFIGURE 2, by sliding the grenade into the end of the barrel of the gun and down the barrel until hp 703 catches in its corresponding groove in the barrel to lock the grenade in the barrel for carrying purposes. When the gun is fired, the projection 212 on front valve 206 strikes the protruding end of plunger 706, causing the pointed end 707 of the plunger to puncture the area 705 of cylinder 704. At the same time, the gas held under pressure in front chamber 201 of the gun 200 is released through front valve 206, propelling the grenade from the barrel and toward the target.

When the area 705 of cylinder 704 is punctured, the contained gas exerts a force upon the pointed end 707 of plunger 706 tending to force the plunger rearward. O-n'ng 708 seals the gas in bore 709 as the plunger 706 is moved rearward. Shoulder portion 710 of plunger 706 engages piston 715 and the force tending to move the piston 706 rearward is transmitted to piston 715; AS piston 715 attempts to move rearward against the con-- tained fluid which fills chamber 713, the force is transmitted to the fluid and forces the fluid through port 716. The rate of flow of the fluid thus metered through port 716 depends upon such variables as the viscosity of the fluid, the diameter of the port 716, and the force applied to the fiuid. The rate of flow of the fluid, and conse quently the rate of travel rearward of piston 715, may be changed by varying any of these variables, preferably the diameter of port 716. The diameter of port 716 is so adjusted that, for a given fluidviscosity, fuse assembly, and gas pressure, the time required from the puncturing of the cylinder 704 to the time that O-ring 708 passes from bore 709 into chamber 713 is the desired fuse delay time.

When the O-ring 708 does pass from bore 709 into chamber 713, the gas which was contained in cartridge 704 is free to pass through port 717 into the interior of case 701. The gas in the cylinder 704 is generally under quite high pressures, for example, about 900 p.s.i., and expands so rapidly into the interior of case 701 so as to cause a shock that splits the case open. The free flowing fire extinguishing chemical which had been contained in case 701 is entrained by the gas and distributed over the area outside the case. For example, when ,a dry powder fire extinguishing powder, such as Foray, is used, the gas will distribute the powder over a circle 5 to 8 feet in radius around the grenade.

While most fluids may be used in thetirne fuse as sembly, it is preferably a liquid which is incompressible and viscous, although gases may be used. Silicone greases have proved to be particularly desirable. They will not freeze under normal winter conditions and have a high viscosity. This high viscosity minimizesthe sealing problem and allows the port 516 in piston 515 to be large and therefore of not so critical a tolerance in manufacture.

The case of the grenade, when made of polyethylene, is

fuse, a grenade may be firedthrough a wall or door, on

the other side of which there is a tire, and have the time fuse operate at such a time as to deposit the free flowing fire extinguishing chemical upon the fire.

An alternative time fuse assembly 800 for the fire extinguishing grenade is shown in FIGURE 8. Pressurized gas cartridge 704 is fitted to the rear of fuse housing 801,

with the easily punctured area 705 of the cartridge facing the rear of the grenade. Plunger 802 is inserted in axial bore 803 of the fuse housing, and pointed end 807 is so arranged to puncture area 705 of the gas cartridge when the protruding end of the plunger is struck. Shoulder 804 in bore 803 engages shoulder 805 on the plunger to keep the plunger from being forced out of the rear of the bore when the gas cylinder is punctured. If necessary, a gasket or O-ring may be inserted to fit between and seal the area between the two shoulders when they are forced together.

Bore 806 leads from bore 803 to pressure chamber 807, located in enlarged portion808 of fuse housing 801.'Pressure chamber 807 is connected to, the interior of the grenade by bore 809. Large piston 810 separatespressure chamber 807 and secondary pressure chamber 811, which are connected by small bore812. Stop 813 keeps the rear face of piston 810 a minimal distance from the rear wall of secondary pressure chamber 811..

Large piston 810 is connected by stem 814 to small piston 815, located in bore 809. O-rings 816 and 817 seal the outer surfaces of

pistons

810 and 815, respectively. As will be appreciated from a description of the operation of the time fuse, small piston 815 must have a crosssectional area considerably smaller than that of large piston 810.

In operation, the rear end ofplunger 802 is struck by the front valve rod-like extension when the fire-extinguish: ing gun is fired. This blow causes the pointed end of the plunger to puncture the area 705 of gas cylinder 704. The pressure of the gas thus released pushes the plunger rearward until it is stopped by the meeting of shoulders 804 and 805.

The gas passes through port 806 into pressure chamber 807. Since the cross-sectional area of large piston 810 is larger than that of small piston 815, the gas exerts a force tending to keep large piston 810 pressing against stop 813. As the small port 812 is open, the gas leaks from pressure chamber 807 into secondary pressure chamber 811. When the pressures in the two chambers are about equal, the forces exerted by the gas in secondary pressure chamber 811 upon large piston 810 and by the gas in pressure chamber 807 upon small piston 815, which tend to move the piston assembly (810, 814 and 815) forward, are greater than the force exerted by the gas in pressure chamher 807 upon large piston 310, which tends to move the piston assembly to the rear, and consequently the entire 9 piston assembly moves forward, When O-ring 817 clears the outer end of bore 809, the gas in the fuse assembly is released to the inside of the grenade, and the sudden shock of the released gas splits the grenade casing.

The diameter of bore 812 is varied to produce different metering rates of the gas passing from chamber 807 to chamber 811. By varying the rate of the gas flow through bore 812, the time from the instant the gas cylinder is punctured until the time the gas pressure in chamber 811 has built up to the point where the piston assembly moves forward can be regulated.

A third time fuse assembly 130 for the fire extinguishing grenade is shown in FIGURE 13. An advantage of this particular fuse assembly is that the fuse time may be varied after the completed grenade is assembled. The

\ time fuse assembly shown in FIGURES 7 and 8 are not adjustable and the fuse time will essentially be that selected at the time of the assembly of the grenade, with possible variations due to temperature changes causing a resultant change in the fluid viscosity or the compressed gas pressure.

Fuse assembly 130 is illustrated as molded to the rear end portion of the grenade. This rear end portion is solvent welded at the rea 137 to the grenade case 701. Plug 135 allows the grenade to be filled with the fire extinguishing chemical after the time fuse assembly 130 is attached to the grenade case 701. The time fuse assembly 130 contains a plunger 706 Which is similar to the plunger of FIGURE 7, except that threads 131 are on the rear portion of the reduced diameter portion 711. Adjustable timing nut 132 is screwed upon the reduced diameter portion 711. Sleeve 134, which comprises the outer walls of chamber 713, has an annular web 133 which is in tight, sliding contact with adjustable timing nut 132. Ports 136 are located in the body of fuse assembly 130.

In operation, firing the grenadeprojecting gun of the present invention delivers a sharp blow to plunger 706, causing pointed end 707 to puncture area 705 of cartridge 704. The compressed gas in cartridge 704 pushes against the pointed end 707 of plunger 706, which is sealed by O-ring 70S. Shoulder portion 710 of plunger 706 engages piston 715 and the force tending to move the piston 706 rearward is transmitted to piston 715. Chamber 713 is filled with an incompressible fluid, such as a viscous silicone grease, and as piston 715 attempts to move rearward, the force is transmitted to the fluid and forces the fluid through port 716. As the plunger 706 moves rearward, it carries with its adjustable timing nut 132. When the plunger 706 moves far enough back, ad justable time nut 132 moves out of tight sliding contact with annular web 133. When this sliding contact is lost, the fluid contained within chamber 713 is allowed to escape, thereby leaving essentially no resistance to the rearward motion of plunger 706, Plunger 706 is therefore slammed rearward until O-ring 708 passes out of contact with bore 709 and releases the compressed gas from cylinder 704 to flow through port 136 and into the interior of the grenade.

One problem existing with the time fuses described above is the fact that temperature changes will cause a change in the pressure of the gas contained in cartridge 704, thereby changing the force (pressure times area) exerted upon the front face of plunger 706, which causes a corresponding change in the fuse time. The fuse of FIG- URE 13 may be adjusted to correct this temperature fuse time change, but such adjustment is necessarily time consuming and inexact.

The time fuse embodiment illustrated in FIGURE 14 produces a constant, predetermined fuse delay time over wide temperature variance, i.e., for example, to 90 F. Mounted upon the reduced diameter portion 711 of plunger 706 are two

pistons

140, 141 and spring 142. The chamber 713, which is similar to the correspondingly numbered chamber of FIGURE 7, is filled with an incompressible fluid, for example, a silicone grease. Front piston 140 contains a sealing lip 143 which maintains close, liquid tight contact with the walls of chamber 713. A number of bosses 144, which may, for example, be of circular cross-section, are mounted upon the rear face of piston 140. A number of ports 145 extend through the piston 140, each port 145 being centrally located in a boss 144. As shown, spring 142 is mounted between the two pistons, 140, 141 and around plunger 706.

Rear piston 141 has a sealing lip 146 riding in close, sliding contact with the walls of chamber 713. The front face of piston 141 is relatively flat, preferably at right angles to plunger 706, and capable of meeting with the rear faces of bosses 144. Port 147 extends through piston- 141. Port 147 should not be in line with any of ports 145, and port 147 should not be covered by a rear edge of a boss 144 when the

pistons

140, 141 contact each other. Chamber 148 is defined by the walls of the fuse housing and

pistons

140, 141. Both

piston

140 and 141 are mounted upon plunger 706, in liquid-tight, sliding contact thereupon.

The spring 142 is so chosen that the force to deform it is equivalent to the force applied to the front face of piston 706 at the lowest contemplated or design operating temperature. The port size is chosen such that the desired fuse delay time will be achieved at the predetermined, lowest contemplated operating temperature. As mentioned, a large number of ports 145 extend through a corresponding number of bosses in front piston 140. The size of bores 145 is not critical, but they are chosen of such a number and size as to be of much greater crosssectional area than bore 147, e.g. the total cross-sectional area of ports 145 may be 5, 10, or even 20 times the cross-sectional area of port 147.

In operation, the time delay fuse of FIGURE 14 produces a constant fuse delay time over a wide temperature range. At the predetermined, lowest contemplated temperature, for which spring 142 and port 147 were designed, the effect of front piston 140 will be small or negligible. The force exerted upon the front face of plunger 706 by the gases released from cylinder 704 is transmitted to front piston 140 by shoulder 710 of the plunger 706. This force is in turn transmitted to rear piston 141 by spring 142, the whole piston assembly consequently having a tendency to move in the rearward direction. Chamber 713 is filled with an incompressible liquid. As rear piston 141 attempts to move rearward, the force from the gas pressure on plunger 706 and the

pistons

140, 141 is transmitted to the incompressible liquid, thereby metering the liquid through port 147. Due to the metering effect, the force exerted on the incompressible liquid in chamber 713 is slightly less than the force exerted upon the front face of plunger 706. Therefore, the spring 142 is not fully compressed and the opposing faces of front piston 140 (i.e., the rear faces of bosses 144) and rear piston 14-1 do not meet. The liquid metered through port 147 passes into the cavity 143 between the two pistons and is then released through ports 145. As previously mentioned, the fuse assembly, and especially port 147, have been designed to produce the desired, predetermined fuse delay time at this low temperature.

A variance of F. in temperature may cause a considerable change in the pressure of the gas contained in cylinder 704. For example, if the gas is carbon dioxide, a rise in ambient temperature of 100 F. may produce a three-fold increase in gas pressure. With the time delay fuse of FIGURE 14, such an increased gas pressure will not affect the fuse delay time, although the force exerted upon the front face of plunger 706 is much larger than that exerted at low temperatures.

If, for example, the ambient temperature is at the higher end of the contemplated temperature range, the force transmitted to front piston may be three times the magnitude of the force exerted at low temperatures.

which was designed to meter at a low temperature. The

increased force exerted upon rear piston 141 causes a corresponding increase in the pressure exerted upon the incompressible liquid, which pressure may be significantly larger than the force exerted upon the liquid at low temperature operation.

As the incompressible liquid is under a greater force, and consequently is exerting greater internal pressure, and front piston 140 is likewise under a greater force, there is a tendency for

pistons

140, 141 to move together, i.e., the force exerted upon front piston 140 moving the same rearward and the force exerted by the liquid tending to retard rearward movement of rear piston 141 overcome the spring 142 and compress the same, thereby allowing the rear face of bosses 144 to contact the front face ofrear piston 141. Such contact of front piston 140 and rear piston 141 effectively seals the flow of the incompressible liquid past front piston 140. The force exerted upon the incompressible liquid still causes metering through port 147 until the pressures in chamber 713 and chamber 148 are approximately equal. When the pressures in the two chambers 713, 148 are approximately equal, spring 142 forces rear piston 141 rearward and out of sealing contact with the rear face of bosses 144. The liquid contained. within chamber 148 is then free to pass through ports 145 until the spring is again compressed and the two pistons come into sealing contact, thus again restricting the flow.

Of course, in actual operation the above-described cyclic contact by the front piston 140 and rear piston 141, with the corresponding sealing of liquid flow through front piston 140, reaches an equilibrium stage wherein the

pistons

140, 141 are maintained in close but not contacting relationship, i.e. the pistons are at such a distance from one another that they produce a metering effect of the fluid through ports 145 without actually stopping the flow therethrough. This equilibrium metering effect is predetermined by the selection of the spring 142 and the size of port 147, and will operate automatically over a wide temperature range.

Close examination of the time delay fuse of FIGURE 14 will show that, irregardless of the force exerted upon front piston 140, the effective force exerted upon rear piston 141 is that transmitted by the spring 142. At low temperatures and pressures, the spring 142 transmits the entire force exerted upon front piston 140 to rear piston 141. At higher temperatures and pressures the spring exerts the same force as at lower temperatures. The additional force exerted upon front piston 140 is cancelled by the balanced pressure existing between cham-.

bers 713 and 148. In other words, at equilibrium conditions during high temperature operation, the flow rate of the incompressible liquid through port 147 will be approximately the sarne as the flow rate at low temperatures, in spite of changes in gas pressure.

FIGURE 15 is a sectional view, showing the front face of rear piston 141. As illustrated, port 147 opens into chamber 148 inside of spring 142. This port 147 may open into any portion of chamber 148 with two limitations. First, the port should not be in line with a port 145 in piston 140. Secondly, the port 147. should not have its liquid flow restricted by the rear face of boss 144 or by spring 142 when the pistons 140,141 approach or contact each other. Even when

pistons

140, 141 are in tight contact with one another, port 147 should be so located as to freely pass the incompressible fluid into all portions of chamber 148.

FIGURE 16 is a sectional view of the rear face of front piston 140; Eight bosses 144 with contained ports 145 are illustrated. Any number of bosses and ports may be utilized, as long as the crosssectional area of ports 145 12 is appreciably larger than the cross-sectional area of port 147.

FIGURE 17 illustrates an embodiment of the .time delay fuse of FIGURE 14, and additionally illustrates a modification of the time fuse arming mechanism.

In FIGURE. 17, instead of port 147 passing through the rear piston 141 of FIGURE 14, the clearance between rear piston 171 and plunger 706 is so adjusted as to, in effect, produce an annular orifice 177, defined by the bore of piston 171 and the outer surface of plunger 706. Like-.

wise, instead of a number of ports 145 as shown in FIG- URE 14, the orifice. or port means of front piston may be an annular clearance or gap between front piston 170 and the wall of chamber 713. In such an instance, chamber 178 between front piston 170 and rear piston 171 must be designed to permit fluid pressure to be applied to essentially the entire face of piston 171 when

pistons

170, 171 are in sealed contact.

A modified time delay fuse arming means is illustrated in FIGURE l5.Instead of having plunger 706 struck by an extension 212 of front valve 206, diaphragm 150 may be employed to cause pointed end 707 of plunger 706 to puncture area 705 of gas cylinder 704. As illustrated in FIGURE 17, diaphragm 150, which is incontact with plunger 706,-is mounted on the rear grenade case 701. The size of diaphragm 150 is so chosen as'to exert a sufficient force on plunger 706 to puncture cartridge 704 at the predetermined pressure of the gas used to operate the grenade projecting gun. The diaphragm 150 may be attached to the rear of plunger 706 or may be in tight sliding contact with an axial extension 172 of the fuse housing 702. Such a diaphragm arming mechanism is advantageous in that an imperfectly loaded grenade will still be activated or armed when the grenade is fired from the grenade projecting gun.

The grenade of FIGURE 7 is easily adapted-to operate as a hand-thrown fire extinguishing device. The plunger 706 may be lengthened to extend past the outer face of plug 712. The base of the grenade can be struck on a hard object to puncture the cylinder 704 and the grenade can then be thrown toward the fire.

However, the handle on the grenade shown in FIG- URE 9 is the preferred. modification for arming by hand. This handle mechanism is much less likely to cause an accidental arming of the fuse and is easily operated and reliable.

In FIGURE 9, the grenade 900has the same basic time fuse as FIGURE 7. Handle 901 is molded on to the rear of plug 712. Lever 902 is mounted on handle 901 by pivot pin 904. Safety pin 903 keeps the lever from moving unless the pin is removed. Extension 905 is so arranged on lever 902 that as the lever is moved toward the handle the extension 905 pushes plunger 706 into the grenade and punctures the cartridge 704. After puncturing the cartridge, the gun may beheld in the hand as long as desired, as long as lever 902 is kept depressed, as extension 905 keeps the plunger 706 from moving rearward and O-ring 708 seals any gas which may be released from cylinder 704 around pointed end 707 of the plunger, When the lever 902 is released the time delay fuse starts in operagon. The grenade may then be thrown by hand toward a As the free flowing fire extinguishing chemical, many various compounds may be used. Dry powders, such as Foray and Purple K, produced by Ansul Chemical Co., are the preferred compounds. Liquids such as Freon F-1301 (bromo-trifiuoromethane produced by Du Pont, may be used. Also, the foam known to the trade as light water may be utilized as the fire extinguishing chemical. More than one fire extinguishing chemical may be used in the grenade of the present invention. I

Any aiming device such as thoseused on rifles or mortars may be mounted on the fire-fighting gun of this invention. The preferred embodiment is a bubble quadrant calibrated for range indication. However, any conventional aiming device may be used.

While for fire-fighting purposes the preferred material inside the grenade is a free flowing fire extinguishing chemical, the scope of this invention covers any material which is adapted to be projected in a grenade or canister. Included among such materials, for'example, are carbon tetrachloride, tear gas, explosives, napalms, smoke-producing compounds, marking powders, insecticides, and various plant killing compounds. The grenade may readily be modified to carry an attached life line, and the compressed gas in the grenade may be used to inflate a life ring when at the desired target.

Although the balanced spool valve is the preferred valve system for triggering operations, obviously a number of modifications could be made. Separate air inlet and outlet ports with two or more separate valves could be used, for example. In such cases it is preferred, but not essential, that the valves be quick-opening.

The stock assembly may be attached to the gun at areas other than the rear housing. The auxiliary chamber 221 may be eliminated with the consequent elimination of most of rear housing 218 if the stock assembly is attached to another point on the gun. While the safety lock assembly is desirable, it is not necessary for operation of the gun.

I claim:

1. A fire extinguishing grenade-projecting device for arming and projecting a fire extinguishing grenade by means of compressed fluid, said device comprising means for holding a fire extinguishing grenade, valve means operated by fluid pressure acting on differential piston areas to release compressed fluid and direct the compressed fluid into said means for holding a fire extinguishing grenade, said valve means in associated relationship with arming means, said arming means adapted to deliver a blow to the base of a grenade contained within said means for holding a fire extinguishing grenade, whereby a grenade contained within the means for containing a fire extinguishing grenade is armed and projected from the gun upon operation of said valve means.

2. A fire extinguishing grenade-projecting device as claimed in claim 1, comprising, a rear and a front pressure chamber, a rear valve seating in the rear of said rear pressure chamber and a front valve seating in the front of said front pressure chamber, said valves connected by a valve stem and said rear valve of larger surface area exposed to internal fluid pressure than said front valve, said pressure chambers connected by a port containing a one-way flow regulating device permitting fluid flow only from said rear pressure chamber to said front pressure chamber, a valve system for controlling the flow of fluid to and from said rear pressure chamber, a barrel adapted to hold and guide a fire extinguishing grenade mounted in front of said front valve, and a projection on said front valve adapted to strike the rear face of a grenade contained in said barrel when said front valve is unseated.

3. The device of claim 2 wherein said valve system for controlling the flow of fluid to and from said rear pressure chamber is a balanced spool valve.

4. The device of claim 2 wherein a multiplicity of barrels are attached to the front end of the front pressure chamber, rotating means are attached to the front receiver and the multiplicity of barrels are rotated by the rotating means in front of the front pressure chamber and front valve whereby grenades contained in each barrel may be fired from the gun in turn.

5. The device of claim 4, wherein said rotating means comprises a piston, a connecting rod, a ratchet and a gas port connecting the front pressure chamber with the face of the piston, whereby gas pressure in the front pressure chamber exerts a force on the piston, the piston driving the connecting rod, the connecting rod rotating the ratchet, the ratchet connected to the multiplicity of barrels and rotating the barrels.

6. In a device for projecting fire extinguishing grenades as claimed in claim 1, the combination of a front pressure chamber and a rear pressure chamber, the chambers in line, a wall separating the chambers, a port defined by the wall and running through the wall, a one-way flow regulating device located in the port and permitting fluid flow only from the rear pressure chamber to the front pressure chamber, a rear valve seating at the rearmost end of the rear pressure chamber, a front valve seating at the front end of the front pressure chamber, the front valve having a smaller surface area exposed to the interior of the front pressure chamber than the rear valve has exposed to the interior of the rear pressure chamber, a valve stem connecting the front valve and the rear valve and passing through the wall, compressed gas supply means for supplying gas to the rear pressure chamber, valve means for controlling the flow of gas into and out of the rear pressure chamber, a barrel attached to the front end of the front pressure chamber and adapted to contain grenades and to receive the flow of gas when a ditferential pressure in the front and rear pressure chambers, acting on differential valve surface areas, operates the valves.

7. The device of claim 6 wherein said valve means is a balanced spool valve.

8. The device of claim 6 wherein a multiplicity of barrels are attached to the front end of the front pressure chamber, rotating means are attached to the front receiver and the multiplicity of barrels are rotated by the rotating means in front of the front pressure chamber and front valve whereby grenades contained in each barrel may be fired from the gun in turn.

9. The device of claim 8, wherein said rotating means comprises a piston, a connecting rod, a ratchet and a gas port connecting the front pressure chamber with the face of the piston, whereby gas pressure in the front pressure chamber exerts a force on the piston, the piston driving the connecting rod, the connecting rod rotating the ratchet, the ratchet connected to the multiplicity of barrels and rotating the barrels.

10. A fire extinguishing grenade consisting of a grenade case filled with free flowing fire extinguishing chemicals, a compressed gas cylinder, and a time fuse assembly means which is armed by a blow delivered to the rear of the grenade case and is operated bycompressed gas from the cylinder, whereby compressed gas from the compressed gas cylinder is released to the interior of the grenade case, thereby rupturing the case, at a predetermined time.

11. The grenade of claim 10, wherein the gas cylinder is attached to the time fuse assembly means, a plunger is contained within the time fuse assembly means, and the gas cylinder is punctured by the plunger when the plunger is struck.

12. The grenade of claim 11 wherein the time fuse assembly means consists of a plunger mounted in a bore defined by the time fuse assembly means, a compressed gas cylinder mounted at the inner end of the bore defined by the time fuse assembly means, sealing means on the plunger, a piston located on the plunger, a chamber defined by the time fuse assembly and containing a liquid and the piston, a shoulder on the plunger to engage the piston and move the piston rearward when the plunger moves rearward, a small port extending through the piston for metering the liquid, and gas escape ports leading from the chamber to the inside of the grenade case.

13. The grenade of claim 12 wherein fuse time adjusting means are mounted on the plunger.

14. The grenade of claim 11 wherein said time fuse assembly consists of said plunger mounted in a bore, said gas cylinder mounted at the inner end of said bore, a first port connecting said bore to a first pressure chamber, a second pressure chamber immediately to the rear of said first pressure chamber and separated from said first pressure chamber by a first piston, a second port in said first piston connecting said pressure chambers, a third port connecting said first pressure chamber with the interior 1 5 of said grenade case, a second piston arranged in said third port to seal the same before arming, a stem connecting said pistons, said second piston being of smaller area than said first piston.

15. The grenade of claim 12 wherein said time fuse assembly is operated by the metering of a fluid through a small port, said fluid being forced through the port by gas pressure from the cylinder.

16. The grenade of claim 12 wherein said time fuse asserhbly is operated by differential piston areas exposed to compressed gas from said cylinder, which releases said compressed gas to the inside of said grenade case after a predetermined time.

References Cited UNITED STATES PATENTS Malcolm 124-11 Woodberry 102-82 Smith 102-82 Pearson et a1. 169-36 Talbot 169-36 Englis 124-11 Frevel 124-11 EVERETT W. K1RBY,'Primary Examiner.

Claims

1. A FIRE EXTINGUISHING GRENADE-PROJECTING DEVICE FOR ARMING AND PROJECTING A FIRE EXTINGUISHING GRENADE BY MEANS OF COMPRESSED FLUID, SAID DEVICE COMPRISING MEANS FOR HOLDING A FIRE EXTINGUISHING GRENADE, VALVE MEANS OPERATED BY FLUID PRESSURE ACTING ON DIFFERENTIAL PISTON AREAS TO RELEASE COMPRESSED FLUID AND DIRECT THE COMPRESSED FLUID INTO SAID MEANS FOR HOLDING A FIRE EXTINGUISHING GRENADE, SAID VALVE MEANS IN ASSOCIATED RELATIONSHIP WITH ARMING MEANS, SAID ARMING MEANS ADAPTED TO DELIVER A BLOW TO THE BASE OF A GRENADE CONTAINED WITHIN SAID MEANS FOR HOLDING A FIRE EXTINGUISHING GRENADE, WHEREBY A GRENADE CONTAINED WITHIN THE MEANS FOR CONTAINING A FIRE EXTINGUISHING GRENADE IS ARMED AND PROTECTED FROM THE GUN UPON OPERATION OF SAID VALVE MEANS.