US3439614A

US3439614A - Variable combustible delay arrangement

Info

Publication number: US3439614A
Application number: US689234A
Authority: US
Inventors: Robert W Schnepfe Jr
Original assignee: AAI Corp
Current assignee: Textron Systems Corp
Priority date: 1965-09-24
Filing date: 1967-11-22
Publication date: 1969-04-22
Anticipated expiration: 1986-04-22

Description

A ril 22, 1969 R. w. SCHNEPFE, JR

VARIABLE OOMBUSTIBLE DELAY ARRANGEMENT- Original Filed Sept. 24, 1965 Sheet Roberf M. .Schnepfo dr. \f INVENTOR F/g. BY -I /L ATTORNEY April 22, 1969 R. w. SCHNEPFE, JR 3,

VARIABLE COMBUSTIBLE DELAY ARRANGEMENT Original Filed Sept. 24, 1965 Sheet 3 of2 Fig. 4

Robert W .Sc/mapfe Jr INVENTOR 036 m ATTO NEY

United States Patent 3,439,614 VARIABLE COMBUSTIBLE DELAY ARRANGEMENT Robert W. Schnepfe, Jr., Timonium, Md., assignor to AAI Corporation, Cockeysville, Md., a corporation of Maryland Continuation of application Ser. No. 490,043, Sept. 24,

1965. This application Nov. 22, 1967, Ser. No. 689,234 Int. Cl. F42b 11/42, 27/00 U.S. Cl. 10264 9 Claims ABSTRACT OF THE DISCLOSURE A cylindrical canister dispenser arrangement is disclosed for ejecting a mass of material into the atmosphere. The canister arrangement employs a spring-biased striker which contacts a percussion primer to ignite a variable time delay fuze which, after a predetermined period of time, fires a propellant charge to create a high gas pressure which propels a piston away from the fuze end of the cylindrical canister to cause a frangible cover plug to be blown away and the mass of material expelled through the resulting hole. The variable time delay fuze has a rotatable body with a longitudinal bore therein containing 21 slow-burning powder and a plurality of ports that are longitudinally and angularly spaced apart from each other so as to provide combustible communication between the slow-burning powder and a relatively fastburning fuze which is in combustible communication with the propellant.

This application is a continuation of prior copending application, Ser. No. 490,043, filed Sept. 24, 1965, now abandoned.

This invention relates to a variable delay propellant device and dispenser, and more particularly to a variable delay fuze and propellant charge arrangement which may be incorporated into a grenade type dispenser.

In the use of grenades or other canister dispensers which employ a propellant charge for ejection of a mass of material into the atmosphere it is often desirable to employ a time delay device which may be varied to selected time intervals by an operator in order to enable the launching or throwing of the grenade and subsequent firing of the propellant charge at a remote distance from the operator. It is a major feature and object of this invention to provide a suitable simple and relatively inexpensive, reliable variable delay arrangement which may be and is according to the invention incorporated into a grenade.

It will also be appreciated from a reading of the detailed description of the invention that the variable delay arrangement may itself be employed in other devices than grenades, and particularly where it is desired to initiate actuation of a variable delay device by percussive action and thereafter at a selected variable time to ignite a propellant or explosive charge.

Still other objects, features and attendant advantages will become apparent to those skilled in the art from a reading of the following detailed description of one preferred embodiment constructed in accordance with the invention, taken in conjunction with the accompanying drawings wherein:

FIG. 1 is an exploded isometric view of an embodiment of a grenade incorporating a variable delay fuze and propellant charge arrangement according to the invention,

FIG. 2 is an isometric view of the variable delay fuze and propellant charge arrangement, with parts broken away for clarity of illustration,

3,439,614 Patented Apr. 22, 1969 "ice FIG. 3 is a fragmentary sectional view of the grenade of FIG. 1, illustrating the parts in position preparatory to firing of the grenade,

FIG. 4 is an elevation view of the grenade of FIG. 1, in partial section, illustrating the action of the parts thereof in operation.

Referring now in detail to the figures of the drawings, the illustrated embodiment takes the form of a grenade 11 having a canister body 13 onto which is removably fitted at one end a release handle 15 which is held in place in a conventional fashion preparatory to firingby a pull release pin 17.

The handle 15 retains a striker and

springasse'mbly

15a, 15b, the striker 15a being adapted to move into percussive contact with a prime-r 33 under the influence of spring 15b upon release of the handle 15. In the'retained position the handle 15 is fitted over a lip 23b of a variable delay fuze and propellant charge unit assembly 21, hereinafter described in more detail.

The variable delay fuze and charge unit 21 is mounted in a well 19 formed in one end of the canister 13. Delay and charge unit 21 includes a selector 23, the propellant chamber housing 43 and a delay tube 63, the selector 23 being keyed to the delay tube 63 through the medium of interfitting

key flats

23a and 63a on the adjacent surfaces of the selector 23 and delay tube 63, as seen in FIG. 2, and being angularly movable as an effective unit with respect to the propellant chamber housing 43 for selective setting of the delay tube 63 relative to a connecting fuze 51 formed in the body of the propellant chamber housing 43, in order to enable selection of a desired time delay between the primer 33 and a propellant charge C contained in propellant chamber 49 formed in the lower end of the propellant chamber housing 43.

The propellant chamber housing 43 has a reduced diameter portion which fits into a complementary recessed portion on the bottom of the selector 23. A locating recess 42 formed in a protruding annular shoulder 43a of the propellant chamber housing 43 engages with a complementary locating detent 19b formed on the inner surface of the well 19 of canister 13. In the assembled position of the delay fuze and charge unit 21 annular shoulder 43a rests on an annular shoulder stop 19a formed about an intermediate portion of the annular wall of the well 19, and locating detent 19b fits into locating recess 42 to prevent rotation of the propellant chamber housing 43. The fuze and charge unit 21 is retained in position through the medium of retainer pins 41 which extend through complementary transverse holes formed in the end of the canister 13 across the sides of well 19 and which engage with an annular retention groove 39 formed in the angularly movable selector 23.

Selector 23 includes a retaining lip 23b for the anchor end of the handle as mentioned above, and has a pointer 27 for indication of the setting of the selector, and a handle 25 for effecting a desired setting about the longitudinal axis of the fuze and charge unit 21. Time setting indicia may be engraved on the end wall of the canister 13 as indicated by the numerals 2 and 5- shown in FIG. 1, and the handle 25 may include a nipple detent 31 selectively engageable with detent recess formed on the end wall of the canister 13 to provide for precise indexing and retention of the selector 23 in a selected time delay position. It will be appreciated that while the propellant chamber housing 43 is retained against rotation, the selector 213 and delay tube 63 are enabled to be angularly adjusted with respect to the propellant chamber housing for adjustment of the effective time delay, the annular retention groove 39 and pins 41 serving the dual purpose of locking the fuze and charge unit 21 against axial motion while enabling free rotational movement of the selector 23 and delay tube 63.

Selector 23 has a central aperture formed therein which is in registry with a primer 33 retained in a complementary cavity between an annular outer retainer lip 29 and an inner centrally apertured retainer washer 35. Washer 35 has a central aperture 35a formed therein which provides for communication between the primer 33 and ignitable mixed disposed in the delay tube 63. The ignitable mix includes a delay mix 65 which extends along a major portion of the tube 63, and preferably includes an additional relatively thin layer of easily ignitable hot-burning mix disposed between the delay mix 65 and the primer 33.

Any desired delay mix and hot mix may be employed as the need indicates, a suitable delay mix having been found to be:

Percent Zirconium 15 Frit 1 5 Barium chromate 80 Fused and ground glass having a composition of CaO, 3.3% MgO, 16.1% A1203, 19.6% SiO-a 61.0%.

A suitable hot-burning mix is a mixture of 40% zirconium and 60% barium chromate.

Two or more communication ports 69a, 6% are formed in the wall of delay tube 63 for communication between the delay mix 65 and a fuze 51 disposed in longitudinal fuze slot 53 extending along the length of the propellant chamber housing 43 and communicating with the propellant charge in the propellant chamber 49. The communication ports 69a and 6% are filled with a flash mixture 67 of black powder and gum arabic, which mixture serves to insure ignition of the fuze 51 when the delay mix 65 has burned to the level of the communication ports 69a or 6911, as the case may be. In assembly of the delay tube, the delay mix is compounded under substantial pressure, as of the order of 80,000 psi. in dry form to a desired length, such as shown in the illustrative embodiment, and the hot mix is thereupon added and compacted under a similar pressure, the ports 69a and 6% then being filled with a black powder wet with an 8% gum arabic aqueous solution. The black powder is then permitted to dry, and the tube is ready for assembly as a part of the fuze and charge unit 21.

A narrow connection slot 71 is formed between the delay tube 63 and fuze 51 in the propellant chamber housing 43, as the longitudinal fuze slot 53 is spaced from the inner bore of the propellant chamber housing as an aid in lateral retention of the fuze 51 in place. Fuze 51 is preferably a quick, substantially instantaneous burning element or substance, and in the preferred and illustrated embodiment such takes the form of a cotton fiber mass impregnated with black powder extending along the length of longitudinal fuze slot 53 and into contact with the propellant charge in the propellant chamber 49. The lower end of propellant chamber 49 is closed by a blowout disc 45 retained in an annular retainer groove 47 formed in the propellant chamber housing 43. The canister well 19 in which the unit 21 is mounted has a blowout well bottom 190 which has an annular shear groove 19d formed therein for aid in rupture upon ignition of the propellant gas charge C in the propellant chamber 4 9.

In the illustrated embodiment a piston 81 is enclosed in the canister 13 adjacent the bottom of the well 19 and is adapted to move away from the well 19 under the influence of the propellant gases from the charge C to expel a charge of gas, particles, and/or liquid material 35 through a blowout cover plug or disc 113a disposed at the opposite end of the canister 13.

In operation, the operator will grasp the handle 25 and rotate the selector 23 to a desired angular position as indicated by the pointer 27 and setting of the nipple detent 31 in a detent recess 13c, thereby bringing one of the ports 69a or 6% of the delay tube 63 into alignment with the connection slot 71 and fuze '51 in the propellant chamber housing 43. The delay tube 63 has a snug fit with the corresponding bore of the propellant chamber housing 43 to prevent flashover between port 69a and the fuze 51 when port 6% is in registry with the fuze 51. When the port 69a is in angular registry with fuze 51 it will be appreciated that the time delay will be shorter than when the port 69b is in registry with the fuze 51. Having selected the desired time delay, the operator will then pull the release pin 17, and in the event that the grenade is to be thrown or launched, the handle 15 will then be released, whereupon the striker and

spring assembly

15a, 15b will throw the handle 15 to one side and the striker 15a will fire the percussion primer 33, as indicated in FIG. 4. The hot gases from the percussion primer 33, will initiate combustion of the hot mix 73 and in turn the delay mix in delay tube 63, the delay mix then burning in a relatively slow fashion progressively along its length toward the lower end as viewed in FIGS. 2-4. Upon the burning zone of the delay mix 65 reaching the port 69 in registry with the connection slot W1 and fuze 51 the flash mix 67 in the respective port 69 Will be ignited and initiate ignition of the fast burning fuze 51 which will in turn cause ignition of the propellant charge C in chamber 49. The propellant charge C, which may be of any conventional and desired ignitable gas-forming mix, will upon ignition cause injection of the blowout disc 45 from its annular retainer groove 47 and effect rupture of the well bottom 19c, whereupon the expanding propellant gases will cause longitudinal movement of the piston 81 to effect rupture and blowout of the blowout plug 13a at the opposite end of the canister 13, the ejection charge being thereupon ejected into the atmosphere through the opening formed by rupture of the blowout plug 13a.

It will be readily appreciated that when the port 6912 is in registry with the connection slot 71 and fuze 51, the ignition of the flash mix 67 in port 69a will not effect ignition of the fuze 51 in view of the lateral displacement of the port 69a from the connection slot 71 and the relatively tight fit of the delay tube 63 in the propellant chamber housing 43. In such instance then the fuze 51 will not be ignited until the delay mix 65 burns to the level of 69b, whereupon the action is the same as described above except that the time involved in reaching the port 6% is proportionately longer than the time in reaching the port 69a and consequently the time delay between actuation of the primer 33 and ignition of the propellant charge C is proportionately longer than when the port 69a is in registry with the connection slot 71 and fuze 51.

While the invention has been described with respect to one preferred embodiment, it will be apparent to those skilled in the art that various modifications may be made without departing from the scope and spirit of the invention. For instance, any desired number of laterally and longitudinally displaced flash ports 69 could be formed in the delay tube, within the bounds of flashover prevention, it being appreciated that the closer the ports are together, either longitudinally or laterally, the greater the likelihood of flashover. In the illustrated embodiment a distance of approximately one-half inch longitudinal spacing and approximately 45 angular spacing having a surface spacing of approximately one-quarter inch in circumferential distance has been satisfactory. As a modification in the event that flashover should become a problem with shorter spacings, one may employ an encasing wiper about the fuze 51 which may have its wiper ends extended through the connection slot 71 into wiping engagement with the surface of delay tube 63. Various other midifications may be of course made as desired or to fit particular circumstances.

That which is claimed is:

1. A grenade comprising a casing having a chamber for an agent to be discharged, and a variable combustible delay fuze and propellant charge device including:

a first body having a combustible fuze extending longitudinally thereof,

a second body having a longitudinal bore and at least two lateral ignition ports therein communcating between said bore and the exterior of said second body, said ports being spaced apart both longitudinally and angularly along said second body,

a combustible time delay element disposed in said second body and extending therein from a position adjacent one of said ports along a longitudinal path past the other of said ports to a position spaced beyond said other port.

an igniter disposed adjacent said last named position and in ignition communication with said combustible time delay element,

said first and second bodies being relatively angularly movable with respect to one another to bring a selected one of said ignition ports into communication with said combustible fuze, and

an ignitable propellant charge disposed in ignition communication with said combustible fuze,

said igniter being a percussion primer,

said percussion primer being disposed in axial alignment with said combustible time delay element,

a positioning selector member separable from said first and second bodies and adapted for rotatable movement of said first body,

said percussion primer being disposed in said positioning selector and having its percussion striker surface disposed adjacent an outer surface of said selector,

said positioning selector having a retaining lip retaining said primer against outward movement upon ignition, and

an apertured internal retainer washer disposed against the inner surface of said primer for aid in retention in position during percussion,

said positioning selector having an external annular groove formed thereon, and

two retainer pins secured in said casing and extending into lateral engagement with said groove for retention of said variable delay fuze and charge device in said casing and enabling rotative adjustment of said selector and second ported body.

2. A variable combustible delay fuze, comprising:

first and second bodies one of said bodies extending within and being rotatably adjustable with respect to the other body about a longitudinal axis thereof,

each of said bodies having a longitudinal chamber formed therein and extending in the direction of said axis,

each of said longitudinal chambers having a combustible substance disposed therein, one of which combustible substances is a relatively slow burning time delay substance,

said first body having at least two lateral ignition ports therein for communication between said chambers,

said ignition ports being spaced apart both longitudinally and angularly along their respective body,

said longitudinal chamber formed in said second body being laterally and continuously open toward said first body through a longitudinal length at least as long as the longitudinal distance subtended by and between said ports,

said combustible substance disposed in said second body chamber extending through a longitudinal length greater than the distance between both of said lateral ignition ports to form a longitudinal burning path from any selected one of said ports to an end ignition zone longitudinally spaced beyond both of said ports.

3. A variable combustible delay fuze according to claim 2,

6. A fuze according to claim 2,

said ports having disposed therein a combustible high intensity flash mixture for aid in igniting of one of said combustible substances by the other of said combustible substances through a selected one of said ports.

7. A fuze according to claim 2,

said combustible substance disposed in said second J body chamber being substantially faster burning .than said combustible substance in said first body to enable relatively fast burning along said longitudinal burning path to said end ignition zone as compared to the time delay burning rate of said combustible substance disposed in said first body chamber.

8. A variable combustible delay fuze and propellant charge device comprising:

charge device comprising:

afirst body having a longitudinal bore and a propellant charge cavity formed therein,

a second body disposed in the bore of said first body and having a longitudinal bore with at least two 7 lateral ignition ports formed therein communicating getween said bore and the exterior of said second said ignition ports being spaced apart both longitudinally and angularly along said second body,

a combustible time delay element disposed in the bore of said second body and extending therein from a position adjacent one of said ignition ports along a longitudinal path past another of said ignition ports to a position spaced beyond said other ignition port,

an ignitable propellant charge disposed in the propellant charge cavity of said first body,

a second enclosed bore formed internally in said first body and extending from said propellant-charge-contaming cavity in a longitudinal direction past one of said spaced ignition ports to a longitudinal position corresponding to another of said spaced ignition ports formed in said second body,

said longitudinally extending and internally enclos d second bore formed in said first body being laterally open toward said second body throughout a longitudinal distance subtended by and between at least two of said spaced ignition ports,

a combustible fuze disposed in said second bore and in ignition communication with said propellant charge disposed in said cavity,

said first and second bodies being relatively angularly movable with respect to oe another to bring a selected one of said ignition ports into communication with said combustible fuze.

References Cited UNITED STATES PATENTS 35,897 1862 Schenkl 102--72 39,682 1863 Schenkl 102-72 44,546 1864 Merryman 10272 2,069,221 2/1937 Coupland 10264 2,763,212 9/1956 McCaslin 102-72.

BENJAMIN A. BORCHELT, Primary Examiner.

JAMES FOX, Assistant Examiner.

US. Cl. X.R.