US2924176A - Centrifugally armed and self-destroying impact fuze - Google Patents

Description

Feb. 9, 1960 A. G. NEUWIRTH, JR., ETAL CENTRIFUGALLY ARMED AND SELF-DESTROYING IMPACT FUZ'E Filed Sept. 21, 1955 2 Sheets-Sheet 1 INVENTORS Alnia E-NEL1WiI t1L Ur:

Furka H. Thompson BY i i): fl w- ATTOR NE Y5 Feb. 9, 1960 A. G. NEUWIRTH, JR, ET AL ,1

CENTRIFUGALLY ARMED AND SELF-DESTROYING IMPACT FUZ E Filed Sept. 21, 1955 2 Sheets-Sheet 2 lNl/ENTO Alui s G. Nauwirth,

FurKe H- Thompson 7 BY ZzM+ if).

' ATTORNEYS United States Patent CENTRIFUGALLY ARMED AND SELF-DESTROY- ING IMPACT F UZE Alois G. Neuwirth, In, St. Louis County, and Parke H. Thompson, Kirkwood, Mo., assignors to the United States of America as represented by the Secretary of the Army Application September 21, 1955, Serial No. 535,773

Claims. (Cl. 102-71) This invention relates to fuzes for spin type projectiles.

An object of the invention is to provide a fuze which is positively held in unarmed position until it develops sutficient spin in flight to move weighted detents, under the influence of centrifugal force, to a position whereby a firing pin is caused to move from unarmed to armed position by movement of the detents.

Another object of the invention is .to provide a fuze having a nose cap of frangible material insuring rapid detonation thereof on impact with. a target constructed of easily penetrated materials.

A further object of the invention is to provide a fuze which will detonate on decay of spin if the projectile penetrates a target without detonation on impact therewith.

Other objects and advantages will be apparent from the following detailed description and the accompanying drawings, in which:

Fig. 1 is a longitudinal sectional view of a fuze disclosing one form of the invention,

Fig. 2 is a transverse sectionalview taken on the line 2-2 of Fig. 1 and looking in the direction of the arrows,

Fig. 3 is a longitudinal sectionalview of the nose cap insert shown in Fig. 1,

Fig. 4 is a detail perspective of one of the detents shown in Fig. 1,

Fig. 5 is a longitudinal sectional view of a modified form of the invention, 7

Fig. 6 is a similar view taken on the line 6--6 of Fig. 5 and looking in the direction of the arrows,

Fig. 7 is a fragmentary longitudinal sectional view of a further modified form of the invention, and

Fig. 8 is a similar view taken on the line 88 of Fig. 7 and looking in the direction of the arrows.

Referring now to Figs. 1 through 4 of the'drawings. The fuze is formed with a body portion 1 rotatable about a longitudinal axis and carrying a booster charge 2. The body portion has an internal cavity 3-in which a generally spherical rotor 4 is movable from a safe to an armed position under the influence of centrifugal force. The rotor has a primer charge 5 'fixed within a diametral bore therein and a recess 6 formed in its surface as will be clear from Fig. l. A firing pin 7 is slidable in coaxial alignment with the axis of the fuze body and engages in the recess 6 to maintain the fuze unarmed by holding the primer charge 5 out of alignment with the firing pin 7 and booster charge 2. In its forward face the body portion 1 is formed with a bore 8 in which is seated the diametrically reduced end 9, of an insert 10, for limiting the rotor 4 to rotation only in the cavity 3. For this purpose it will be noted that body 1 and insert 10 have cooperating recesses 1a and 10a, respectively, fitting smoothly about the corresponding surfaces of the rotor. A nose cap 11 of thin material envelops the insert 10 and the forward part of the fuze body 1 and is secured thereto as at 12 by any-suitable-means such as rdlling. The insert is formed with anaxi'al bore 13 and a. coaxial counterbore 14 providing a shoulder 15 at their "Ice juncture. A head 16 is secured on the forward end of the firing pin 7 and slides in the bore 13 to guide the forward end of the firing pin in axial translation. An annular enlargement 17 forming a shoulder is formed on the firing pin near its rear end. A generally, hollow, frusto-conical first spring housing 18 surrounds the firing pin 7 and has formed thereon a base flange 19 seated against the shoulder 15. As clearly shown upon Fig. 1,

this housing extends real-wardly into counterbore 14. A.

first spring 20, within the first spring housing 18 and surrounding the firing pin 7, is confined between the closed end of the housing 18 and the firing pin head 16 for normally urging the firing pin forwardly. Surrounding the first spring housing 18 and slidable in the counter bore 14 is a second spring housing 21 shown as gener ally cylindrical'in form and enclosing a second spring. 22. The second spring housing is diametrically reduced at its rear end as at 23, to engage the annular enlarge-- ment 17 onthe firing pin 7 and houses the second spring: 22 bearing at its forward and rearward ends upon flange- 19 and reduced end 23 of the second housing, respec-- tively. The second spring 22 is of greater strength than:

spring 20 so that the parts are normally maintained its the position shown upon Fig. 1, with the tip of firing pin 7 seated in recess 6 of rotor 4. It will be noted that the enlargement 17 on the rear end of the firing pin, in conjunction with the reduced end and neck portion of housing 21, define an annular recess.

The insert 10 is formed with longitudinal slots 25 shown as four in number and uniformly spaced around the circumference thereof, Figs. 2 and 3. A detent 26 is positioned in each slot and is dimensioned to have a smooth fit therein. The detents are alike and shaped as clearly shown in Fig. 4, to provide finger 27 which contacts with an abutment 24 on the second spring housing 21. Each detent is confined for movement within its respective slot 25 by the side wall of the nose cap 11 invention all four detents constantly engage the abut ment 24.

The operation of the device shown in Figs. 1 through:

4 is as follows:

When a projectile, to which the fuze is attached, ro-- tates in flight the detents 26 move outwardly in response tocentrifugal force. Themass center of each detent is well forward of its pivot point 28. Consequently each; detent will move "powerfully outwardly to the dotted line position, Fig. 1. During this movement the fingers 27 bear against the annular abutment 24 and move the second spring housing 21 forwardly compressing the second spring 22 and freeing the firing pin 7 for forward movement under the bias of the first spring 20 to armed position. When the rear end of the firing pin is withdrawn from the recess 6 in the rotor 4, the rotor precesses in response to spin of the projectile until the primer 5 is coaxially aligned with the firing pin in fully armed position. If a hit is made on a target the forward end of the nose cap 11 and insert 10 will be deformed and the firing pin will be forced into the primer 5. In the event that the target is too frail to deform the nose cap and insert, and the projectile continues beyond the target, eventual decay of spin will correspondingly lessen forward thrust of the detent fingers 27. In such an event the spring 22 will overcome the lessened thrust of the detent fingers and the bias of spring 20, and will drive the second sleeve 21 and its reduced end 23 against the shoulder formed by the enlargement 17 on the, firing pin and detonate the primer charge 5.

In the modified form of the invention shown in Figs.

and 6 a single spring element is employed instead of the two spring assembly of Fig. l.

A body portion 1' carries a booster charge 2 and a rotor 4 having a primer charge 5 therein normally out of registry with a firing pin 7. A recess 6 is formed in the rotor 4 and in normal safe position is in coaxial engagement with the firing pin. Secured to the forward end of the fuze body, by any preferred means, is a nose cap 11 of thin material. An insert which may be made of frangible material, is fitted within the nose cap and formed with an axial bore 13'. Positioned in the forward end of bore 13 of the insert 10 is a cylindrical guide member 32 having an annular spring seat 33 formed thereon. The firing pin 7 has a diametrically enlarged portion 17' at its rear end forming a shoulder.

An elongated sleeve 34 is slidably supported at its forward end in the cylindrical guide 32 and the firing pin 7 is guided for axial sliding in and by sleeve 34. At its rear end the sleeve 34 is formed with an outturned flange 34a which serves as an abutment for the detents 36 and also for the spring, through the intermediary of an annular reinforcing collar 35, slidably fitting the bore 13. A spring 22 surrounds the sleeve 34 and is confined between the spring seat 33 on the guide 32 and the abutment reinforcing collar 35. In normal safe position the bias of spring 22' directed against the collar 35 and the outturned flange 34a holds the firing pin seated in the recess 6 in the rotor 4.

The insert 10' is formed with longitudinal slots 25" diametrically opposite each other as shown in Fig. 5, and slots 25' diametrically opposite each other and located at an angle of 90 from the slots 25" as shown in Fig. 6. These slots totaling four in number correspond in location, form, and purpose with slots 25 in insert 10 of the form shown at Fig. 3.

Two pairs of detents 26 and 36 of slightly different form and function are employed. The detents 26, Fig. 6, have fingers 27' in contact with the outturned flange 34a on the sleeve 34. Diametrically opposite detents 26 are identical and are confined in respective slots 25' in the insert 10', in the same manner as the detents of Fig. l. The two detents 26', Fig. 6, are each formed with a pointed end 28 which forms a fulcrum and engages a stop member 37 in each slot 25 and pivots thereon under the influence of spin to retract and hold the sleeve 34 and its outturned flange 34a in armed position against the thrust of spring 22'. The two detents 36, Fig. 5, have pointed ends 28 which pivot on the front face 29 of the body portion similar to the detents 26 of Fig. 1 but the fingers 27" of these detents, that is, the fingers which protrude radially behind flange 34a are formed of lesser longitudinal dimension so that when the detents 26' have reached their extreme outward position in flight as shown in dotted lines upon Fig. 6, and are holding the sleeve 34 retracted, the detents 36 will have moved outwardly to the dotted line position shown in Fig. 5, in which position they are free of the outturned flange 34a on the sleeve 34. The fuse thus becomes more sensitive to impact when held in firing position by only one pair of detents, namely, detents 26'.

The operation of the device shown in Figs. 5 and 6 is as follows:

When a projectile, to which the fuze is attached, rotates in flight the detents 26 and 36 move outwardly in response to centrifugal force in the same manner as the detents of Fig. 1. During this movement the fingers 27 of detents 26' and the fingers 27" of detents 36 bear against the outturned flange 34a and move the sleeve 34 forwardly compressing the spring 22' and freeing the firing pin to float in the sleeve 34 and creep forward during flight thus freeing rotor 4 for precession to armed position. When the sleeve and spring are retracted to armed position and the detents 26' are in the broken "line position of Fig. 6. the detents 36 are released and 4 moved to the broken line position of'Fig, 5 .so that the fuze is held in armed position by the detents 26 only.

A further simplified form of the invention is shown in Figs. 7 and 8. A body portion 1 carries a rotor 4 having a primer charge 5 therein normally out of registry with a firing pin 7a. A recess 6 is formed in the rotor and in normal safe position is in coaxial engagement with the firing pin. Secured to the forward end of the fuze body, by any preferred means, is a nose cap 11 of thin material. An insert 10a, which may be made of frangible material is fitted within the nose cap and formed with an axial bore 13a and a counterbore 14a. The firing pin 7a has an enlarged head 16a slidable in .the bore 13a and annular grooves 40 near its rear end. All annular separable member 41 surrounds the firingpin and is engaged in the grooves 49. The separable member slides in the counterbore 14a and serves as an abutment 24a similar to the abutment of Figs. 5 and 6. At the juncture of the bore 13a and the counterbore 14a a shoulder 15a is formed between which and the separable member 41 a spring 22a is confined. centrifugally operated detents 36a are movable in slots 25a in a manner similar to the operation of detents 36 in Fig. 5. Detents 2611 are movable in slots 25g in a manner similar to the operation of detents 26' in Fig. 6. A bore 8a is formed in the body portion 1 and has seated therein a retainer ring 42 for holding the detents assembled in their slots and also to form a surface upon which the pointed ends 28a of the detents 36a will pivot. The ends 28b of'the detents 26a will pivot on the front face 29a of the body portion 1, as clearly shown in Fig. 8. Fingers 27a of detents 26a and 36a bear against the abutment 24a for retracting the firing pin and spring to armed position.

The operation of the device shown in Figs. 7 and 8 is I as follows:

In flight the detents 26a and 36a move outwardly in response to centrifugal force. During this movement the fingers 27a of the detents 36a pivot away from the abutment 24a while the fingers27a on the detents 26;: remain in contact with the abutment and hold the spring 22a compressed and the firing pin 7a in armed position. On impact with a target the nose cap and insert are deformed and the firing pin is projected into the primer 5. 'In the event that the detents do not yield to the force of impact the separable member 41 will release itself from the annular grooves 40 and let the firing pin slide through to strike the primer 5.

While we have disclosed three forms of the present invention presently preferred by us, various changes and modifications will occur to those skilled in the art after a study of the present disclosure. Hence the disclosure is to be taken in anillustrative rather than a limiting sense; and it is our desire and intention to reserve all modL fications falling within the scope of the subjoined claims.

Having now fully disclosed the invention, what we claim and desire to secure by Letters Patent is:

1. In an impact detonated fuze having a body portion, a nose cap secured on the front end thereof and having an insert therein, a cylindrical guide member in said nose cap having an annular spring seat, a centrifugally operated rotor having an ignition charge and a recess therein and being movable from a safe to an armed position, an axially disposed firing pin having its rear end engaged in the recess and having an enlargement thereon forming a shoulder, an elongated sleeve surrounding said firing pin and slidable thereon, an annular abutment on the rear end of said sleeve normally engaging the firing pin shoulder, a spring surrounding said sleeve and firing pin and being confined between said abutment and annular spring seat normally urging said firing pin into the recess, and a centrifugally operated detent in engagement with said annular abutment and pivotable on the body under the influence of spin for retracting said sleeve and abutment, compressing said spring, and releasing said firing pin to float freely in said sleeve and creep forward to armed position on forward acceleration said detent being operable on decay of spin to release said annular abutment to the bias of said spring whereby said firing pin is urged into the primer.

2. in an impact detonated fuze having a body portion, a nose cap secured on the front end thereof, an insert in said nose cap having a series of slots diametrically disposed and circumferentially spaced, at centrifugally operated rotor having an ignition charge and a recess therein and being movable from a safe to an armed position, an axially disposed firing pin having its rear end engaged in the recess and having an enlargement thereon forming a shoulder, an elongated sleeve surrounding said firing pin and slidable thereon, an annular abutment on the rear end of said sleeve normally engaging the firing pin shoulder, a spring surrounding said sleeve and firing pin and being confined between said abutment and nose cap normally urging said firing pin into the recess, a first pair of diametrically opposite centrifugally operated detents confined for opposite radial movement in the diametrically opposite slots in said insert and in engagement with said annular abutment and pivotable on the body under the influence of spin for retracting said sleeve and abutment, compressing said spring, and releasing said firing pin to float freely in said sleeve and creep forward to armed position, and a second pair of dimetrically opposite centrifugally operated detents confined in diametrically opposite slots in said insert and in engagement with said annular abutment and pivotable on the body under the influence of spin for assisting said first pair of detents during initial retraction of said abutment and spring and later releasing said abutment and spring to be held by said first pair of detents.

3. A centrifugally armed impact detonated fuze having a body, a spherical rotor mounted for universal rotation within said body, a primer charge axially disposed within said rotor, a recess on the periphery of said rotor, an axially disposed firing pin having its rear end in engagement with said recess in unarmed position for holding said charge at an angle to said firing pin, said firing pin having an annular abutment member mounted thereon, spring means mounted in said body to restrain said firing pin in said recess to maintain said rotor in the unarmed position, and a plurality of centrifugally operated detents abutting said body in unarmed position and initially pivotable in response to spin of said body to urge said abutment member forward against the action of said spring means to efiect removal of said firing pin from said recess and releasing said rotor for precession to thereby align said charge with said firing pin, at least one of said detents being so shaped as to move clear of and release said abutment upon extended pivoting.

4. A centrifugally armed impact detonated fuze as set forth in claim 3 wherein said firing pin has a beveled annular recess therein, said annular abutment member mounted on said firing pin in engagement with said recess and releasable therefrom upon impact with said target.

5. A centrifugally armed impact detonated fuze having a body, a spherical rotor mounted for universal rotation Within said body, a primer charge axially disposed Within said rotor, a recess on the periphery of said rotor angularly disposed relative to said charge, an insert secured to the front end of said body, a firing pin axially disposed within said insert having its rear end in engagement with said recess in unarmed position to hold said charge at an angle to said firing pin, said firing pin having an annular abutment member mounted thereon, a spring surrounding said firing pin and engaging said abutment member to restrain said firing pin in said recess, said insert having a plurality of radially disposed guide slots, a series of centrifugally operated detents in engagement with said abutment member, said detents having a width slightly less than the widthof said guide slots and pivotable on the body within respective guide slots in response to spin of said body to urge said abutment member forward against the action of said spring to eifect removal of said firing pin from said recess releasing said rotor for precession to thereby align said charge with said firing pin at least one of said detents being so shaped as to move clear of and release said abutment upon extended pivoting.

References Cited in the file of this patent UNITED STATES PATENTS 2,014,393 Mathsen Sept. 17, 1935 2,564,797 Thompson Aug. 21, 1951 2,626,568 Podnos Jan. 27, 1953 2,641,186 Apotheloz June 9, 1953 FOREIGN PATENTS 505,338 Great Britain May 9, 1939 580,243 Great Britain Sept. 2, 1946 928.644 France June 9, 1947 138.839 Sweden Jan. 20, 1953 1,063,268 France Dec. 16, 1953

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