US2779287A - Contact fuze - Google Patents

Description

Jan. 29, 1957 L M ANDREWS ET AL 2,779,287

CONTACT FUZE Filed Nov. l, 1951 2 Sheets-Sheet l :Eff-5- Jan. 29, 1957 L.. M. ANDREWS ET AL 2,779,287

CONTACT FUZE Filed Nov. 1, 1951 2 sheets- sheet 2 ,2 22 INVENTORJ; Laurence JV[..An;fr-ews [6a ,5 /5 /la BYJacnh Rahn-law United States Patent O CONTACT FUZE Laurence M. Andrews and Jacob Rabinow, Takoma Park,

Md., assignors to the United States of America as represented by the Secretary of the Army Application November 1, 1951, Serial No. 254,429

11 Claims. (Cl. 102-81.2)

(Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by and for the Government of the United States of America for governmental purposes without the payment to us of any royalties thereon or therefor.

The present invention relates to a fuse for aircraft cluster bombs which will detonate upon impact.

More particularly, the present invention relates to a fuse for use in the cluster type bomb dropped from aircraft, and which is designed to become armed upon being subjected to a strong, sustained air blast to detonate upon impact.

ln the use of cluster bombs which are dropped from aircraft to detonate upon impact, it is desirable that the fuse for each bomb in the cluster be so designed that it will be armed by sustained rapid air travel, but will remain unarmed if subjected to a continued, relatively weak air blast or by a strong air blast which is of short duration.

Also desirable is a fuse which is designed so that it will not become accidently armed by ordinary handling or if dropped. However should accidental arming occur, the provision of a precautionary measure to give visual indication of such arming, and to prevent assembly into the cluster in armed condition, is also an advantageous feature.

It is therefore an object of this invention to provide a fuse incorporating all the aforementioned desirable features.

It is also an object of this invention to provide a fuse for a cluster bomb which will become armed, and which will remain locked in armed position, by a strong, sustained air blast maintained for the required time, but which will not become armed when subjected to a continued, relatively mild, air blast, -ory a strong air blast of short duration.

It is also an additional object of this invention to provide a fuse having an impeller and vanes responsive to air pressure to actuate a gear train to move an arming block and primer from first safe position to second armed position.

It is also a further additional object of this invention to provide a fuse including a precautionary measure to prevent the assembly of the fuse incorporating bomb into a cluster, and which will give a visual indication that the fuse is armed.

With these and other objects in view which will become apparent as the following specification develops, reference is made to the accompanying drawing wherein:

Figure 1 is a View of a plurality of bombs as they may be mounted in a bomb bay;

Figure 2 is a diagrammatic section taken on line 2-2 of Figure 1 and showing the arming block and safety pins schematically;

Figure 3 is a longitudinal section taken on line 3-3 of Figure 5;

Figure 4 is a forward elevation of the fuse looking toward the rear of Figure 3 (position and relation of parts as during descent of bomb);

2,779,287 Patented Jan. 29, 1957 Figure 5 is a transverse section taken on line 5-5 of Figure 3;

Figure 6 is a section taken on line 6-6 of Figure 3;

Figure 7 is a longitudinal section of the fuse in an armed position, but with parts rearwardly positioned as when the bomb has been subjected to a short, strong air blast;

Figure 8 is a longitudinal section of the fuse in armed and operated position;

Figure 9 is a fragmentary longitudinal section similar to Figure 3 showing a modification of the fuse, and

Figure 10 is a view showing another modification of the fuse.

Referring to Figure 1, a support 1 within the bomb bay has mounted thereon a plurality of cups 2, for receiving the tail iin assembly 3 which forms no part of the present invention and is therefore not shown in detail but which will be brieiiy described. The fin assembly comprises an end plate 3a, an opposing end plate 3b to which is secured by brackets a plate 3c joined in any convenient manner to a bomb casing 4 containing incendiary or other material. Secured between plates 3a and 3b are a plurality of shafts 3d upon which are mounted vanes spring biased to pivot outwardly when the bomb is released from cup 2. In their outwardly extended position the vanes will afford stabilization and drag to the bomb. However in stowed or folded position the tins are confined to a. diameter approximately equal to that of the bomb, thus the bombs in a cluster may nest closely together without danger of the tins of one bomb entangling those of an adjacent bomb.

Referring to Figure 3, the fuse body is provided with a hexagonally shaped housing 5 having a reduced rear portion 5c which is counterbored as at 5d. The reduced portion 5c is externally threaded at 5a so that it can be screwed into container 4 shown in Figure 1. The reduced portion is also internally threaded as at 5b to receive within the counterbore 5d a booster cup '7 containing the booster S. Also fixedly disposed within the counterbore 5d, contiguous with and directly forward of booster 8 is a block 9 having an axial bore 9a to receive a cylindrical capsule 10 of soft easily fracturable metal containing detonating material 10a. Formed .integral with hexagonal housing 5 at the forward end is a reduced hollow cylindrical portion 11 having a plurality of holes 12 formed in its walls to permit the escape of air when the bomb is descending. The inner peripheral wall of cylinder 11 is inwardly stepped forwardly as at 11a to form a shoulder 11b for ixedly supporting a spider 13 having a centrally located bearing 14, and journaled in this bearing is a rearwardly axially extending impeller shaft 15 upon which is mounted for rotation, in radial alinement with holes 12, a turbine rotor or impeller 16 having forwardly depending vanes 16a (see Figures 3 and 4). The rearmost extremity of shaft 15 is pointed as at 15a to form a striking pin. Apertures 13a are formed between the legs of spider 13 to permit an air blast to impinge against impeller 16.

Counterbore 5d in the reduced rear portion 5c extends forwardly into housing 5 and is substantially closed oif by an inwardly extending portion or partition 40 of housing 5 to provide a space d1 to accommodate arming block 30, security pin 6 and other moving parts in a manner to be subsequently described. A forwardly stepped substantially cylindrical axial bore 42 of larger diameter than bore 5d is formed in the remaining portion of hexagonal housing 5 forward of partition 40. A ring 19 forming a rear shoulder 19a and forward shoulder 19b is secured in any convenient manner to the inner wall of the forward half section of bore 42. A disc shaped flat plate 13 loosely rests on shoulder 19b for axial movement in bore 42 and a correspondingly heavier at plate disc 27 rests on shoulder 19a and is also axially movable arrasar within bore 42. Plate 18 is pressed forwardly by a concave bevel washer type comparatively weak spring 20 extending between the forward surface of plate 27 and the rear surface of plate 18. Plate 27 is in turn pressed forwardly by a pair of contiguous relatively strong concave bevel type washer springs 2S pressed between the forward surface of partition 4t) and the rear surface of plate 27. Shaft 15 is also journaled in a centrally located hole 18a in plate 18 and a centrally located hole 27a in plate 27. Springs 20, 28 and partition 40 are also centrally apertured to permit striking pin 15a to reciprocate therethrough.

The portion of shaft 15 extending between plate 18 and impeller 16 is of increased diameter and is form-ed as a worm gear 17 (see Figure 6). Meshing with worm 17 is a gear 22 formed on the inner end of a shaft 21 which extends laterally in a direction normal to shaft 15 and is journaled in brackets 21a secured to and depending forwardly from plate 18. Rigidly mounted on the outer end of shaft 21 is a second Worm gear 23 which meshes with a gear 24 mounted on the forward end of a pinion shaft 25 disposed parallel to and eccentric of shaft 15, and extending rearwardly in the fuse housing. Pinion shaft 25 having an elongated pinion gear 25a maintained thereon, is journaled in plate 18 and is received in apertures formed in plate 27 and partition 40, a portion of the pinion shaft and gear also extending into space 41 formed between this partition and block 9. A locating pin 26 is rigidly secured in a bore formed in partition 40 and extends through and slidably ts holes in plates 1S and 27 to prevent these plates from rotating relative to one another and to the housing 5.

Referring to Figures 3 and 5, housing 5 is provided with a lateral recess 44 axially coextensive with and in open communication with space 41 formed between block 9 and partition 40. An arming block 30 extends between block 9 and partition 40 and is slidable therebetween so that in unarmed position the end of the block rests against a closing plug 34 screwed into the wall of housing to close off recess 44 and to permit easy assembly of the parts. Arming block 30 is biased into unarmed position or to the right as seen in Figures 5 and 7 by a spring 31 which surrounds pin 6, said pin being secured in any convenient manner to block 30 to extend laterally outwardly through a bore 45 formed in housing 5 diametrieally opposite recess 44. Arming block 30 is provided with an axial bore 36a for receiving an easily rupturable capsule 32 containing a primer or detonating substance 33. In unarmed position capsule 32 is out of axial alinement with detonating substance a in capsule 10, and striking pin a. When the fuse is armed the two detonating capsules and pin 15a are in axial alinement so that upon impact the pin 15a pierces the bottom wall of capsule 32 to set oft` the primer. Arming block 30 is provided with a rack 29 on the face adjacent to shaft 25 to engage the pinion gear 25a thereupon when the fuse has been subjected to su'icient air pressure to move the fuse parts toward armed position. A roller 29a secured to block 9 and partition 40 is pressed against the face of block 3i) opposite to the side provided with rack 29 to hold arming block 30 in line when it is moving.

The action of the fuse will best be understood by considering Figures 3, 7 and 8. Figure 3 shows the fuse in unarmed position and before the fuse has been subjected to any air pressure. In this position plates 18 and 27 are pressed forwardly by springs 20 and 28, and shaft 15, impeller 16 and pinion shaft 25 are urged to their forwardmost positions so that pinion gear 25a is out of engagement with rack 29. Block 30 is biased to the extreme right as seen in Figures 5 and 7 and capsule 32 is out of axial alinement with capsule 10 and striking pin 15a. As can readily be seen in Figure 5, pin 6 does not protrude beyond the periphery of housing 5, thus facilitating the arrangement of several of the fused bombs into a cluster as previously explained, and as illustrated in .4 Figures 1 and 2. It is to be noted at this time that spring 2t) is calibrated so that an air blast of predetermined strength is required to compress this spring to permit the impeller, shaft and associated gear train, plate 18 and shaft 25 to move rearwardly. Spring 28 on the other hand is an extremely strong spring which will compress only on impact to enable pin 15a to strike the primer in capsule 32. If a moderate air stream passes through the openings in spider 13, as for example, when a bomb be cornes accidently dislodged While it is being loaded into a plane and drops to the ground to be subjected to the air blast from propellers on adjacent planes, this air stream will act upon the vanes and impeller 16 causing it and the associated gear train to rotate. No action will occur as a result of this rotation since spring 20 is not compressed and pinion gear 25a does not engage rack 29.

If on the other hand the blast is suiciently strong to compress spring 20, the associated parts will move rearwardly to cause pinion gear 25a to engage rack 29, and impeller 16 will rotate thereby rotating pinion shaft 25 to move block 30 to the left as seen in Figure 5, against the bias of spring 31, and towards armed position. This position may best be termed semi-armed and is clearly illustrated in Figure 7. However since the air blast is of a shorter duration than that predetermined time required to completely arm the fuse, at the termination of such air blast, spring 20 will return pinion shaft 25 to disengaged position and spring 31 will return block 30 to unarmed position.

It is readily apparent therefore, that only a strong, sustained air blast prolonged for the requisite time, as when a bomb is dropped, will cause block 30 to be driven by the rack, pinion and associated gear train until capsules 32, 10 and striking pin 15a are in axial alinement. The continued air blast will jam the gear train to retain the block in armed position so that upon impact, spider 13 is collapsed, spring 28 is compressed and shaft 1S is driven rearwardly in the fuse, causing striker pin 15a to detonate primer 32, detonator 10 and booster 7 to cause the bomb to function. Figure 8 illustrates the fuse in completely armed position and after impact. Since in completely armed position pin 6 protrudes outwardly from housing 5, if the fuse were to become accidently armed in handling and preparatory to arranging into a cluster, this condition would give visual indication to the handler that the fuse is armed, and would also preclude nesting of the bombs into a cluster until the fuse was again rendered safe.

Figure 9 is a modification of the fuse illustrated in Figures 1-8 wherein shear pins 28a are substituted for spring 28. These pins may be made of metal sufficiently strong to withstand all air pressures and to shear off onlty. in response to strong impact as when the target 1s 1t.

Figure l0 is another modification of the fuse wherein coil springs 28b are substituted for spring 28 to act in like manner as spring 28 or shear pins 28a.

Other modications and alterations of the structure which has been disclosed herein for purposes of illustration will be apparent to one skilled in the art, and it is obvious that the same may be made without departing from the spirit and scope of the invention as defined in the following claims.

We claim:

1. A fuse including an arming block transversely slidable from safe to armed position in a bore located rearwardly in said fuse, a detonator eccentrically disposed in said block when in safe position, a vaned impeller journaled in the nose of said fuse for transverse rotation and axially rearward translation in response to a blast of air, means in said fuse resiliently biasing said vaned impeller in a direction opposed to said rearward translation, means in said fuse rearwardly axially movable integrally a predetermined distance with said impeller against the bias of said resilient means and in response to a blast of air to engage said arming block, and a gear train in said fuse actuated by the rotation of said impeller and operatively connected to said block engaging means for moving said block and detonator to armed position in response only to a sustained air blast.

2. The fuse as recited in claim l and including a rearwardly directed ring pin axially disposed in the nose of said fuse, said firing pin also comprising a shaft for said impeller, and means in said fuse normally restraining said firing pin and said vaned impeller against movement beyond said perdetermined distance and actuable upon impact when said fuse is armed to permit said firing pin to forcibly contact said detonator.

3. The fuse as recited in claim l wherein said arming block moving means comprises a pinion shaft, a pinion integral with said pinion shaft, and a rack on said arming block engageable by said pinion.

4. The fuse as recited in claim 1 wherein said arming block moving means comprises a pinion shaft, a pinion integral with said pinion shaft, and a rack on said arming block engageable by said pinion, a rearwardly directed tiring pin axially disposed in the nose of said fuse, said tiring pin `also comprising a shaft for said impeller, and means in said fuse engaging said firing pin and said vaned impeller and actuable upon impact when said fuse is armed to permit said firing pin to forcibly contact said detonator.

5. The fuse as recited in claim 4 wherein said gear train comprises a first worm on said tiring pin, a transverse shaft having a gear on one end to engage said first worm, and a second worm on the other end of said transverse shaft meshing with the pinion on said pinion shaft.

6. The fuse as recited in claim 5 and including a security pin fixed to said arming block on one end and having its other end extending into a transverse bore formed in said fuse, said pin having a length to protrude beyond the outer peripheral wall of said fuse only when said fuse is armed, and a helical spring surrounding said pin and abutting said block to normally bias said block in safe position.

7. In a fuse having a body symmetrical about a longitudinal axis, there being an elongated axial bore formed in said body, an arming system for said fuse comprising an arming block supported rearwardly in said bore for transverse movement from safe position to armed position, said arming block having an eccentric longitudinal bore for receiving a detonator, a vaned impeller journaled in op posed transverse walls in the nose of said fuse for transverse rotation and rearward axial movement in response to a blast of air, resilient means in said elongated bore biasing said vaned impeller in a direction opposed to said rearward movement, a rack on said arming block, a rearwardly directed pinion shaft disposed forwardly in said elongated bore, an elongated pinion integral with said pinion shaft, means providing a connection between said impeller and said pinion shaft whereby said pinion shaft moves integrally in a rearward direction with said impeller a predetermined distance against the bias of said resilient means to engage said rack in response to an air blast, and a gear train actuated by rotation of said impeller and operatively connected to said pinion shaft to rotate said last named shaft and move said detonator and arming block to armed position in response only to 1a sustained blast of air.

8. rIhe fuse recited in claim 7 and including a rearwardly directed firing pin axially disposed forwardly in said elongated bore, said tiring pin also forming a shaft for said impeller, and means in said fuse normally restraining said firing pin and said impeller against movement beyond said predetermined distance, and actuable upon impact when said fuse is armed to permit said ring pin to forcibly contact said detonator,

9. The fuse recited in claim 8, wherein said gear train comprises a iirst worm on said firing pin, a transverse shaft having a gear on one end to engage said rst Worm, and a second worm on the other end of said transverse shaft meshing with the pinion on said pinion shaft.

10. The fuse as recited in claim 9, and including a security pin fixed to said arming block on one end and having its other end extending into transverse bore formed in said body, said pin having a length to protrude beyond the outer peripheral wall of said. body only when said fuse is armed, and a helical spring surrounding said pin and abutting said block to normally urge said block to safe position. i

1l. In a fuse, a body having reduced rearward and forward portions and a central hexagonal portion, there being a longitudinal bore formed in said body, an arming block mounting an eccentrically disposed primer supported rearwardly in said central hexagonal portion and transversely slidable from safe to armed position, a vaned impeller journalled in said forward reduced portion for transverse rotation and axially rearward movement in response to a blast of air, means in said body resiliently biasing said vaned impeller in a direction opposed to said rearward movement, means in said body rearwardly axially movable integrally with said impeller a predetermined distance against the bias of said resilient means and in response to a blast of air to engage said arming block, a gear train in said body actuated by the rotation of said impeller and operatively connected to said block engaging means for moving said [block and detonator to armed position in response only to a sustained air blast, a security pin fixed to said block and movable therewith through a transverse bore in said hexagonal portion, said pin adapted to lie entirely within said body when said fuse is unarmed, a helical spring surrounding said pin and biasing said block to safe position, said pin adapted to extend beyond the periphery of said body when said fuse is armed to give a visual indication of said arming.

References Cited in the tile of this patent UNITED STATES PATENTS 1,726,325 Varaud Aug. 27, 1929 1,842,467 Woodberry Ian. 26, 1932 2,407,844 Moriarty Sept. 17, 1946 2,409,205 Graumann Oct. 15, 1946 2,420,237 Girouard May 6, 1947 2,447,941 Imber et al Aug. 24, 1948 2,450,910 ORear Oct. 12, 1948 2,644,398 Rabinow July 7, 1953

Images