US3117522A - Set-back device for fuze - Google Patents

Description

Jan. 1 1964 F. c. HUTCHISON ETAL 3,117,522

SET-BACK DEVICE FOR FUZE Filed Nov. 30. 1960 INVENTORS, Frank E-Hur.chis EITL nElLhanm.Fa1es 1%" 0a +4.4 WM

United States atent 3,117,522 SET-BACK DEVICE FOR FUZE Frank C. Hutchison, Greenfield, N.H., and Nathan M. Fales, Westwoo'd, Mass., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Army Filed Nov. 30, 1960, Ser. No. 72,802 1 Claim. (Cl. 102-78) This invention relates to a setback device for a fuze and more particularly to a fuze incorporating safety features necessary in the safe handling of artillery type fuzes.

It is a precautionary requirement in the handling of artillery ammunition fuzes that after its assembly to a projectile, the assembly may be dropped, rolled and otherwise roughly handled without the initiation of the firing train. It is also essential, that when the projectile is fired, the explosive train will not function until the projectile has traveled a sufliciently safe distance from the gun in its trajectory so as not to injure the gun crew.

It is therefore a primary object of the present invention to provide a setback device for an artillery ammunition fuze to prevent the fuze from functioning until it has traveled a sufficient distance from a gun, when fired therefrom, in order to provide safety for the gun crew.

It is another object to provide a set-back device for a fuze in which a detonator rotor is first rotated clockwise, then counterclockwise, to align the detonator with an explosive train, thus affording a time delay in the functioning of the fuze.

A further object is to provide a setback device for a fuze in which the detonator carrying rotor of the invention is rotated clockwise by an unbalanced mass and then counterclockwise by spring means.

It is a still further object to cause the aforesaid rotor to be locked in its armed position when finally rotated therein.

The specific nature of the invention as well as other object and advantages thereof, will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

FIG. 1 is a top plan view of one embodiment of a fuze of the invention, illustrating its approximate position in a projectile, the projectile being shown in broken lines;

FIG. 2 is a view of the fuze of FIG. 1, the cover being removed to expose a portion of the setback mechanism;

FIG. 3 is a cross sectional view taken along line 33 of FIG. 1;

FIG. 4 is an axial sectional view taken along line 44 of FIG. 1;

FIG. 5 is a detail section taken along line 5-5 of FIG. 1; 1

FIG. 6 is a detail section taken along line 66 of FIG. 4; and

FIGS. 7, 8 and 9 are schematic views showing the positions of the rotor during its travel from a safe to an armed position in the fuze.

Referring to the drawings:

A fuze is indicated generally by 1 and is positioned in a projectile P, the projectile being shown in broken lines. Fuze 1 comprises a cylindrical body 2 and is axially bored as at 3 at its rear and as at 4 at its frontal portion for providing passageways for an explosive train from a booster (not shown) to a firing pin or like detonating element (also not shown). Body 2 is bored at right angles to bores 3 and 4 as at 5 and is counter-bored as at 6 for a purpose which will be apparent later. A cut out portion '7 is provided for receiving operating elements therein.

A cylindrical rotor, generally indicated by 8 is mounted for rotation in bore 5 and has a first downwardly depending integral shaft 9 rotatable in counter bore 6.

An unbalanced, sequential mass 10 is located at the under side of rotor 8 and is integral therewith for simultaneous rotation together. 1

Rotor 8 carries a detonator 11 in such a location as to lie in the same axis as bores 3 and 4 when the rotor is in its armed position in body 2.

A cap 12 is fitted in the cut out portion 7 in body 2 and has a central opening 13 to receive a shaft 14 integral with the upper portion of rotor 8 and in axial alignment with shaft 9. A disc 15, having a notch 16 in its circumferential edge, is integral with the upper side of rotor 8 and shaft 14, and is also received within cap 12 as best seen in FIG. 4.

A setback responsive, angular release arm 17 is pivoted to cap 12 by a screw 18 :and is secured thereon by a cap screw 19. Arm 17 is disposed in spaced relation between the underside of cap 12 and disc 15 and is provided with a tang 20 at its free end which is adapted to be received in notch 16 as is best viewed in FIG. 2.

Rotor 8 is normally urged in a counter clockwise direction by a coil spring 21 which encircles a cap 22 fixed for rotation with shaft 14. Spring 21 has one end received in a slot 23 in shaft 14 and its other end is held by a screw 24 in cap 12.

Means are provided for locking rotor 8 in its armed and unarmed positions and consists of a spring biased plunger 25 (see FIG. 3) slidable in a bore 26 and in the safe position of the fuze, plunger 25 is in contact with shoulder 28 of the unbalanced arcnate mass 10 which holds the mass and rotor against rotation.

In operation, assuming that projectile P with fuze 1 attached thereto has left the muzzle of a gun (not shown), projectile spin moves plunger 25 out of contact with shoulder 28 of the unbalanced mass 10 and into bore 26 to clear bore 5 thereby freeing unbalanced mass 10 and the rotor 8 from its restraining action. At the same time arm 17 is rotated rearwardly (as shown in FIG. 8) to move tang 20 out of notch 16 in disc 15 which also acts to release rotor 8 which then rotates clockwise due to the influence of set back force upon the unbalanced mass.

Upon cessation of set-back force, rotor 8 is then rotated in a counterclockwise fashion due to the torsion of spring 21 (see FIG. 9) until detonator 11 is aligned with axial bores 3 and 4 to complete the explosive train and arm the fuze. Plunger 25 now will enter hole 27 in unbalanced mass 10 to prevent detonator 11 from accidently rotating out of alignment with the aforesaid bores and cause malfunction of the fuze.

Other variations and modifications may be effected without departing from the scope of the novel concept of the present invention as set forth in the claim.

What is claimed is:

A fuze for attachment to a projectile comprising in combination, a body having a first axial bore, a second bore normal to and intersecting said first bore, a third bore spaced from and parallel to said second bore, there being a cut-out portion in the outer wall thereof, said cutout portion being coaxial with said second bore, a dernountable cap received in said cut-out portion, a rotor mounted for rotation in said body and rotatable about an axis normal to said first bore, upwardly and downwardly extending shafts integral with said rotor, said shafts being axially aligned and journaled in said cap and said second bore respectively, a detonator in said rotor and disposed normally out of alignment with said first bore; an unbalanced, arcuate mass integral with the inner end of said rotor, said mass defining an arcuate cut-out and having a hole therein, said cut-out forming at least one shoulder; means for preventing rotating of said rotor comprising, an angular arm pivoted at one of its ends to the underside of said cap and having a downwardly depending tang integral with the inner side of its free end, a disc having a notch in its circumferential edge, said disc being secured on the 'upper'side of said rotor, said tang being in releasable engagement with the notch in said disc; means normally urging said rotor in a counter clockwise direction comprising a'torsion spring having one ofits ends fixed to the upper end of said shaft; its other end being secured to said "cap; and detent means for locking said rotor when in an armed position comprising, a spring biased plunger slidably mounted in said third bore in said body and normally biased into engagement with said shoulder on said unbalanced mass, said plunger function ing upon projectile spin to move into said third bore and toutof engagement with'said shoulder to release said unbalanced mass, whereupon during set back force, said arm will be caused to rotate rearwardly to move said tang on said arm out of the notch in said disc to permit said rotor, disc and unbalanced mass to rotate in a clockwise direction due to continuing set back force until said set back force ceases, whereupon said torsion springwill rotate said rotor in a counter-clockwise direction until said plunger snaps into said hole in said unbalanced mass to lock said rotor in an armed position, whereby said detonation is in axial alignment in said first bore in said body.

References Cited in the'file in? this patent UNITED STATES PATENTS 2,448,228 MccaSlin et al. Aug. 31, 1948 2,586,437 RabinOW Feb, 19, 1952 2,709,962 Funk et a1 June 7, 1955 2,900,998 Burrell Aug, 25, 1959 2,948,219 S app Aug. 9, 1960 2,978,982 'Bian'chi Apr. 11, 1961 3,000,315 Anastasia et al Sept. 19, 1 961 r

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