US3552318A

US3552318A - Ordnance fuze

Info

Publication number: US3552318A
Application number: US726379A
Authority: US
Inventors: George S Briggs
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1968-05-03
Filing date: 1968-05-03
Publication date: 1971-01-05
Anticipated expiration: 1988-01-05

Abstract

An arming mechanism for an ordinance fuze which is protectively covered and sealed prior to deployment of the weapon containing the fuze. A prescored cover is torn from the fuze during deployment of the weapon to allow a plurality of vanes normally housed within the fuze to be extended externally of the fuze casing by a spring. The vanes are circumferentially constrained about an arming rod such that upon rotation within the airstream the arming rod is axially removed from the fuze detonator.

Description

United States Patent [72] Inventor George S. Briggs 2,396,245 3/1946 Butler, Jr. et a1. 102/81.2 Adelphi, Md. 2,498,043 2/1950 Lauritsen l02/8l.2 [21] Appl. No. 726,379 2,544,860 3/1951 Rasmussen... l02/8l.2 [22] Filed May 3, 1968 2,750,888 6/1956 Wynn 102/81.2X [45] PaHFmed ,1971 Primary Examiner-Benjamin A. Borchelt [731 Asslgnee The United States of America as represented Assistant Em m iner Thomas Webb by the secretary 9" Navy AtlorneysJ. P. Dunlavey, J. O. Tresanskyand S P. l-jisher [54] ORDNANCE FUZE 6 Claims, 2 Drawing Figs.

ABSTRACT: An armlng mechanism for an ordnance fuze [52] :IS. (51. 4 l02/8L2 which is protectively covered and sealed prior to dep|oymem [51] C F42 /5; 24 1 9 70 4 of the weapon containing the fuze. A prescored cover is torn c i c from the fuze during deployment of the weapon to allow a plu- Fleld 01' Search 102/8 1 .2 m of vanes normally housed within the fuze to be extended [56] References cied externally of the fuze casing by a spring. The vanes are circumferentially constrained about an arming rod such that UNITED STATES PATENTS upon rotation within the airstream the arming rod' is axially 1,141,540 6/1915 Hale 102/8 1 .2 removed from the fuze detonator.

1 /.9 I J G 2/ l0 so 54 PATENTEDJAN Si n 3.552.318

SHEET 2 [IF 2 ORDNANCE FUZE BACKGROUND OF THE INVENTION This invention relates generally to ordnance fuzes, and more particularly to a vane armed fuze particularly useful in bombs.

Bomb fuzes are known in the prior art which utilize a vane structure external of the bomb fuze case and rotatable by the airstream passing the bomb during descent. Prior art fuzes utilizing a vane structure for arming purposes have located the vane structure adjacent the forward exterior surface of the bomb fuze, generally in an exposed condition. It has been necessary to provide expensive and complicated sealing arrangements for the rotor of the vane structure of suchfuzes. One obvious problem with an exposed vane structure is that the vane structure is readily accessible and easily tampered with, and the fuze may be prematurely armed. Another disadvantage of an exposed vane structure is that during storage or shipping the vanes are susceptible to damage. Attempts have been made in the past to provide such vane structures with protective covers. However, a protective cover which is exterior of the fuse casing is necessarily bulky, and substantially adds to the overall dimensions of the fuze.

SUMMARY OF THE INVENTION Accordingly, one object of this invention is to provide a new and improved vane armed fuze for aerial ordnance vehicles.

Another object of the invention is the provision of new and improved fuze having a vane-type arming mechanism initially disposed within the fuze casing and extendable therefrom upon deployment of the fuze.

Briefly, in accordance with one embodiment of this invention, these and other objects are obtained by providing a fuze having a casing with an open end, a cover sealing the open end of the casing, a vane-type arming mechanism initially within the casing, and means for extending the vane-type arming mechanism externally of the casing in response to removal of at least a portion of the cover.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings wherein like reference characters designate identical or corresponding parts throughout the several views, and more particularly to FIG. 1 thereof wherein the fuze of the present invention is shown as having a casing indicated generally at with a lower closed end casing section 12 secured to an upper open ended casing section 14 having an enlarged diameter portion and a reduced diameter portion by conventional means such as threaded engagement at 16. The open end of upper casing section 14 is provided with a circular flat cover plate 18 having a perpendicularly extending circumferential portion I9 with an inwardly turned lip 21 for engagement about a circumferential flange 20. A seal ring 22 may be provided between the upper end of flange and the underside of cover 18 to provide a positive seal for the fuze casing.

As more clearly seen in FIG. 2, the cover plate 18 has prescored groove 24 formed on the top surface thereof with a tab 26 secured to the portion 28 surrounded by groove 24 by means such as a rivet 30. i

An elongate cavity 32, as shown in FIG. 1 is centrally formed in the reduced diameter portion of the upper casing section 14 for housing a detonator mechanism assembly indicated generally at 34. The detonator assembly 34 consists essentially of an elongate cupshaped member 36 having a axial bore therethrough with a small initiator charge 38 held' in place in a lower reduced diameter portion 43 of the axial bore and a generally cylindrical striker member having a firing pin 42 secured to the lower end thereof in axial alignment with charge 38. A bore portion 44 provides a passage between initiator charge 38 and a booster pyrotechnic charge (not shown) located in the lower portion 46 of lower casing member 12, such that upon detonation of the initiator charge 38 the main fuze charge will be detonated. The striker member 40 and charge holding member 36 initially are held apart by a helical coil spring 48.

To prevent premature fuze detonation, an elongate arming and safing rod 50 is provided with a first portion 52 on the lower terminal end thereof which is maintained in engagement with the detonator, to prevent initiation thereof, by a second intermediate portion 54 which is screwthreaded for engagement with casing 14 at 55 and a third upper end portion 56 which is capable of being rotated to withdraw the first portion 52 from the detonator by unscrewing the second portion 54 from the casing 14.

A radial bore 58 extends completely through striker member 40 and has disposed therein a pair of diametrically opposed freely moving ball detents 60. When in the assembled position, as shown in FIG. 1 the ball detents 60 are maintained in engagement with a chamfered surface 62 of member 36 by the first portion 52 of rod 50, thus preventing striker member 40 from moving axially within the charge holding member 3.6.

A tubular sleeve 64, having a plurality of impeller blades such as cup shaped wind vanes 66 radially extended from the upper end thereof, is slidingly mounted on the upper terminal portion 56 of rod 50. The

complimentary surfaces

68 and 70 of tubular sleeve 64 and rod 50, respectively, are of a generally rectangular configuration, such that the tubular sleeve 64 is constrained from rotational movement about rod 50. Thus, the sleeve 64 is free to slide axially along rod 56, but is circumferentially constrained such that rotary movement of the sleeve 64 cause by rotation of vanes 66 will necessarily cause corresponding rotation of rod 50. A stop member 72 is located on an upper end 74 of a tubular extension 76 of the center portion of upper casing member 14 to limit upper movement of tubular sleeve 64 by engaging enlarged diameter surface portion 78 of sleeve 64.

Upon housing of the fuze within a bomb, the tab 26 on cover 18 is secured to the delivery vehicle, for example, an aircraft, such that, upon bomb release, the portion 28 will be torn away from the cover along prescored groove line 24 to expose the vanes 66 and sleeve 64. Biasing means such as a coil spring 80, located within the lower portion of sleeve 64, forces sleeve 64 and the attached vanes 66 upperwardly until surface 78 engages stop member 72. In the extended position the vanes 66 are exposed to the slipstream of the falling bomb and rotate. The inner surface 68 of sleeve 64 will engage upper portion 82 of the third portion 56 of rod 50 when in extended position. As the slipstream rotates vanes 66, rod 50 will be rotated to effect threaded disengagement of the intermediate portion 54 of the rod from casing section 14, thus gradually withdrawing the first portion 52 of rod 50 upwardly thereby to disengage detent balls 60 enabling the balls to move inwardly, and thus free striker member 40 for movement within charge holding members 36. When in the freed position, striker member 40 and charge holding member 36 are free to move toward each other, such that upon target impact firing pin 42 will overcome the force of spring 48 and engage charge 38 for ignition thereof.

Thus it will be recognized by those skilled in the art that by providing the fuze with an arming mechanism which is initially protectively housed within the fuze casing and which is exposed to the airstream only in response to fuze deployment, inadvertent arming of the fuze and damage to the arming mechanism are avoided.

Obviously, the numerous modification and variation of the present invention are possible in light of the above teachings [t is therefore to be understood that in the scope of the appended claims the invention may be practiced otherwise than as specifically described herein.

I claim:

1. A fuze comprising:

an open ended casing having a cavity defined therein;

a detonator within said cavity;

a rod within said casing extending from the open end into said cavity, said rod comprising:

a first portion in engagement with said detonator to prevent initiation thereof, a second portion screwthreaded for engagement with said casing and a third portion rotatable to withdraw said first portion from said detonator by at least partly unscrewing said second portion from said casing;

a cover for said open end of said casing;

a slideable sleeve axially mounted about said third portion of said rod;

a plurality of vanes extending radially from said sleeve, said sleeve and said vanes initially being contained within said casing by said cover; and

biasing means normally urging said sleeve toward said cover.

2. The fuze of claim 1 further comprising means for removing at least a portion of said cover.

3. The fuze of claim 2 wherein said cover has a section thereof prescored for easy removal, and said means for removing at least a portion of said cover is a tab connected to said prescored section.

4. A fuze arming device comprising:

a casing having an open end;

a cover for said open end of said casing,

detonating means within said casing;

a vane arming mechanism normally disposed within said casing; and

means for affecting extension of at least a portion of said vane arming mechanism externally of said casing in response to removal of at least a portion of said cover.

5. A fuze arming mechanism comprising:

a casing having a axial cavity formed therethrough;

a detonator assembly disposed in said cavity;

a rod threadedly disposed in said cavity and having one terminal portion thereof locking said detonator assembly;

a rotatable impeller assembly slidingly mounted on the other terminal portion of said rod capable of imparting rotational movement to said rod upon rotation thereof by an external force; to affect axial withdrawal'of said rod to unlock said detonator assembly;

shearable means for normally maintaining said impeller assembly within said cavity; and

resilient means for urging said impeller assembly outside of said cavity upon shearing ofsaid shearable means thereby to be rotatable and to affect axial withdrawal of said rod.

6. A fuze arming mechanism comprising:

a cylindrical casing having an enlarged diameter head portion with an axial cavity formed therethrough said cavity having reduced diameter threaded intermediate portion and enlarged diameter terminal portions;

an elongate rod rotatably positioned in said cavity, said rod having an intermediate threaded portion, a substantially cylindrical end portion and a noncircular end portion;

a detonator assembly disposed in said cavity and normally maintained in an inactive condition by said cylindrical end portion of said rod;

an impeller assembly disposed in an enlarged diameter terminal portion of said cavity and including a plurality of blades affixed to a central sleeve, said sleeve having a noncircular opening therein slideably disposed on said noncircular end portion of said'rod;

a cover member sealing said enlarged diameter terminal portion of said cavity thereby to maintain said impeller assembly in a position enclosed by said casing, said cover member including a weakened portion for effecting severance of a center portion thereof in response to an external force; and

a coil spring abutting said sleeve for urging said impeller assembly to a position substantially external of said casing whereby rotational movement may be imparted to said impeller assembly and said rod thereby to disengage said cylindrical end portion of said rod from said detonator to activate said fuze.

Claims

1. A fuze comprising: an open ended casing having a cavity defined therein; a detonator within said cavity; a rod within said casing extending from the open end into said cavity, said rod comprising: a first portion in engagement with said detonator to prevent initiation thereof, a second portion screw-threaded for engagement with said casing and a third portion rotatable to withdraw said first portion from said detonator by at least partly unscrewing said second portion from said casing; a cover for said open end of said casing; a slideable sleeve axially mounted about said third portion of said rod; a plurality of vanes extending radially from said sleeve, said sleeve and said vanes initially being contained within said casing by said cover; and biasing means normally urging said sleeve toward said cover.

4. A fuze arming device comprising: a casing having an open end; a cover for said open end of said casing, detonating means within said casing; a vane arming mechanism normally disposed within said casing; and means for affecting extension of at least a portion of said vane arming mechanism externally of said casing in response to removal of at least a portion of said cover.

5. A fuze arming mechanism comprising: a casing having a axial cavity formed therethrough; a detonator assembly disposed in said cavity; a rod threadedly disposed in said cavity and having one terminal portion thereof locking said detonator assembly; a rotatable impeller assembly slidingly mounted on the other terminal portion of said rod capable of imparting rotational movement to said rod upon rotation thereof by an external force; to affect axial withdrawal of said rod to unlock said detonator assembly; shearable means for normally maintaining said impeller assembly within said cavity; and resilient means for urging said impeller assembly outside of said cavity upon shearing of said shearable means thereby to be rotatable and to affect axial withdrawal of said rod.

6. A fuze arming mechanism comprising: a cylindrical casing having an enlarged diameter head portion with an axial cavity formed therethrough, said cavity having reduced diameter threaded intermediate portion and enlarged diameter terminal portions; an elongate rod rotatably positioned in said cavity, said rod having an intermediate threaded portion, a substaNtially cylindrical end portion and a noncircular end portion; a detonator assembly disposed in said cavity and normally maintained in an inactive condition by said cylindrical end portion of said rod; an impeller assembly disposed in an enlarged diameter terminal portion of said cavity and including a plurality of blades affixed to a central sleeve, said sleeve having a noncircular opening therein slideably disposed on said noncircular end portion of said rod; a cover member sealing said enlarged diameter terminal portion of said cavity thereby to maintain said impeller assembly in a position enclosed by said casing, said cover member including a weakened portion for effecting severance of a center portion thereof in response to an external force; and a coil spring abutting said sleeve for urging said impeller assembly to a position substantially external of said casing whereby rotational movement may be imparted to said impeller assembly and said rod thereby to disengage said cylindrical end portion of said rod from said detonator to activate said fuze.