US3715987A

US3715987A - Fuze for a nongyratory projectile

Info

Publication number: US3715987A
Application number: US00136065A
Authority: US
Inventors: R Morel; R Simmen
Original assignee: Mefina SA
Current assignee: Mefina SA
Priority date: 1970-05-14
Filing date: 1971-04-21
Publication date: 1973-02-13
Anticipated expiration: 1990-02-13
Also published as: DK133445B; NO129310B; FR2091122A5; BE766482A; GB1296326A; AR199456A1; AT307928B; DE2122185A1; BR7102893D0; DK133445C; SE362952B; NL7106573A; ES391113A1; CH517932A

Abstract

THE FUZE, E.G. FOR A MORTAR, CAN BE DETONATED INSTANTANEOUSLY ON IMPACT OR, BY PREVIOUS ADJUSTMENT, WITH A TIME DELAY, THE FUZE HAS A PRIMARY FUSE FOR DETONATION ON IMPACT BY A FIRING PIN BUT IS HELD SPACED FROM THE LATTER BY A LOCKING DEVICE WHICH CAN BE UNLOCKED BY THE AXIAL ACCELERATION DUE TO DEPARTURE OF THE SHOT. THE FUZE ALSO HAS A DETONATOR SAFETY DEVICE COMPRISING A SECONDARY FUSE AND A HOLDER MOVABLE TRANSVERSALLY TO THE AXIS OF THE FUZE TO BRING THE SECONDARY FUSE OPPOSITE THE DETONATOR. TIME DELAY OF THE SECONDARY FUSE IS PROVIDED BY A CLOCKWORK MOVEMENT ROTATING A TOOTHED SECTOR. A SECOND FIRING PIN FOR THE SECONDARY FUSE ACTS AS A STOP BLOCKING THE

TOOTHED SECTOR IN INACTIVE POSITION. THE SECOND FIRING PIN IS BORNE BY A PLUNGER SLIDABLE AXIALLY IN THE FUZE. A BALL BLOCKING MECHANISM FIXES THE PRIMARY FUSE HOLDER AND THE PLUNGER RIGIDLY TO ONE ANOTHER AS LONG AS THE PROJECTILE HAS NOT UDERGONE IMPACT AFTER DEPARTURE OF THE SLOT. IMPACT RELEASES THE BLOCKING BALLS ENABLING THE PLUNGER AND THUS THE SECOND FIRING PIN TO BE DRIVEN BACK BY A SPRING, WITH THE TIME DELAY, AGAINST THE SECONDARY FUSE.

Description

Feb. 13, 1973 R. MOREL ErAL 3,715,987

FUZE FOR A NONGYRATORY PROJECTILE Filed April 21, 1971 9 Sheets-Sheet 6 INVENTORS PEA/5' 010/251. 72032127 .S/nmm/ BY am z. W.

ATTORNEY Feb. 13, 1973 R. MOREL. ETAL 3,715,987

FUZE FOR A NONGYRATORY PROJECTILE Filed April 21, 1971 9 Sheets-Sheet 7 INVENTORS PEA E M025!- RaaEET S/MMEA/ BY WC'DRNEY Feb. 13, 1973 R. MOREL ETAL 3,715,987

OOOOOOOOOOOOOOOOOOOOOOOOOOO LE Filed April 2 1 l 9 71 Feb. 13, 1973 R MQREL ETAL 3,715,987

FUZE FOR A NONGYRATORY PROJECTILE Filed April 21, 1971 9 Sheets-Sheet 9 INVENTOR I? maAEEL 20 E T S/MMEN RNEY 3,715,987 FUZE FOR A NUNGYRATORY PROJECTILE Reu Morel and Robert Simmen, Geneva, Switzerland, assignors to Mefina S.A., Fribourg, Switzerland Filed Apr. 21, 1971, Ser. No. 136,065 Claims priority, application Switzerland, May 14, 1970, 7,240/70 Int. Cl. F42c 1/08 US. Cl. 102-74 Claims ABSTRACT OF THE DISCLOSURE The fuze, e.g. for a mortar, can be detonated instantaneously on impact or, by previous adjustment, with a time delay. The fuze has a primary fuse for detonation on impact by a firing pin but is held spaced from the latter by a locking device which can be unlocked by the axial acceleration due to departure of the shot. The fuze also has a detonator safety device comprising a secondary fuse and a holder movable transversally to the axis of the fuze to bring the secondary fuse opposite the detonator. Time delay of the secondary fuse is provided by a clockwork movement rotating a toothed sector. A second firing pin for the secondary fuse acts as a stop blocking the toothed sector in inactive position. The second firing pin is borne by a plunger slidable axially in the fuze. A ball blocking mechanism fixes the primary fuse holder and the plunger rigidly to one another as long as the projectile has not undergone impact after the departure of the shot. Impact releases the blocking balls enabling the plunger and thus the second firing pin to be driven back by a spring, with the time delay, against the secondary fuse.

The present invention relates to a fuze for a nongyratory projectile, especially for firing by a mortar, enabling instantaneous detonation of the projectile on impact, or delayed detonation by previous adjustment of the fuze, the latter comprising a primary fuse or initiator for detonation on impact by driving in a firing pin, this primary fuse being fixed to a primary fuse holder subject to the action of a spring tending to push it axially into armed position towards the firing pin, but held in spaced position from the latter by a locking device capable of being unlocked under the action of axial acceleration due to departure of the shot, this fuze comprising also a detonator safety device comprising a secondary fuse or initiator fixed to a secondary fuse holder transversally movable with respect to the axis of the fuze, subject to the action of a spring tending to bring the secondary fuse opposite the detonator, a clockwise movement controlling the passage of the secondary fuse holder from its secured position to its armed position, this clockwork movement comprising a toothed sector subject to the action of the spring, a stop displaceableaxially on departure of the shot locking this toothed sector in inactive position of the fuze.

Projectile fuzes, of the type defined above, are generally of very complicated and expensive construction. For this reason, known fuzes of this type run the risk of faulty operation resulting either from an error of assembly, or from locking or binding of a delicate part.

It is an object of the invention to provide a fuze which overcomes the aforesaid drawbacks.

The fuze according to the invention is characterized by the fact that the stop blocking the toothed sector in inactive position of the fuze is formed by a second firing pin capable of firing the secondary fuse once the latter is in armed position, the second firing pin being borne by a plunger or ram capable of sliding axially in the primary fuse holder against the action of a spring, a ball blocking mechanism rendering the primary fuse holder and the 3,715,987 Patented Feb. 13, 1973 said plunger rigidly fixed to one another as long as the projectile has not undergone impact after the departure of the shot, such impact causing the escape of the blocking balls enabling the plunger and, thus, the second firing pin, to be driven back by their spring, with delay, against the secondary fuse.

In order that the invention may be more fully understood, one embodiment of the fuze according to the invention is described below, purely by way of illustrative but non-limiting example, with reference to the accompanying drawings, in which:

FIG. 1 is a view in elevation, in axial section, showing an embodiment of the fuze according to the invention in secured inactive position,

FIG. 2 is a view similar to that of FIG. 1 showing the fuze after departure of the shot, that is to say after emerging from the ordnance piece,

FIG. 3 is a view similar to the preceding views, showing the fuze at the moment of instantaneous ignition following an impact,

FIG. 4 is a view similar to the preceding views, showing the fuze in position after having undergone impact, when it has been adjusted for delayed detonation,

FIG. 5 is a view similar to the preceding views, showing the fuze in delayed firing position,

FIGS. 6 to 8 are views in section along the line A-A of FIG. 1, showing the three positions of adjustment of the fuze, that is to say respectively: the adjustment position for instantaneous detonation on impact: secured position of the fuze; and adjusted position for delayed detonation, after impact,

FIGS. 9 and 10 are sections along the line B-B of FIG. 1,

FIG. 9 corresponding to the secured position, whilst FIG. 10 corresponds to the delayed detonation,

FIG. 11 is a view in section along the line C-C of FIG. 1, showing the trajectory safety device in unarmed position, and

FIG. 12 is a section along the line D-D of FIG. 2, showing the trajectory safety device in armed position.

Referring to the drawings, the uongyratory projectile fuze shown comprises a body formed of a lower tubular part I screwed inside a part 2 in the general shape of a cap. In the lower end 3 of the part 1 is screwed a part 4 forming a plug and bearing the detonator 5 and its transmitting charge 6.

The part 2 has a cylindrical collar 7 on which is totatably mounted an ogive-shaped part 8. This part 8 is held on the collar 7 due to screws 9 engaged in holes 10 tapped radially in the part 8. These screws 9 have an end portion 11 of smooth cylindrical shape engaged in a peripheral groove 12 of the part 2.

A bore 13 is arranged in the upper end portion of the part 8 to receive a cylindrical ram 14 rigidly fixed to a firing pin 15 arranged in the axis of the fuze. The point of this firing pin 15 is capable of penetrating into a bore 16 of the part 2 through an opening 17. However, this firing pin 15 has a part 18 of rectangular section (see FIGS. 6 to 8) whose large transverse dimension is greater than the width of the passage 17 which is of general rectangular shape. In the position shown in FIGS. 1 to 8, the firing pin 15 cannot thus be driven into the bore 16. On the other hand, in the case of relative angular displacement between the firing pin 15 and the part 2, it is possible to bring the part 18 of the firing pin 15 into correspondence with the rectangular passage 17, this position being precisely the position provided for instantaneous detonation of the fuze on impact.

The firing pin 15 is rigidly fixed angularly to the ogiveshaped part 8 by means of pins 19 driven radially into apertures 20 of the part 8, the end 21 of these pins 19 3 being engaged in a corresponding axial slot 22 arranged in the ram 14 bearing the firing pin 15. These slots 22 hence enable axial movement of the ram 14, but render the latter angularly rigid with the part 8.

This ram 14 has an internal bore 23 inside of which is housed the spring 24 constituting the return spring of the firing pin 15. This spring 24 is supported at one of its ends against the bottom of the bore 23, whilst its other end is engaged around a collar 25 extending the part 2 and surrounding the portion 18 of the firing pin 15. The spring 24 is supported by this end against the upper face 26- of the part 2 forming a portion of the body of the fuze.

A protecting cap 27 covers the upper portion of the ogive-shaped part 8 and is held on the latter by means of a peripheral bead 28 engaged in a groove 29 of the part 8.

The part 2 of the body of the fuze has an inner bore 30 located in the extension of an inner bore 31 arranged in the part 1. Inside these two bores 30 and 3 1 is arranged a sleeve 32 guided axially in the :bore 31. The upper part 33 of this sleeve 32 is of reduced diameter and bears the pri mary fuse 34 which must be ignited by the firing pin 15. This sleeve 32 hence constitutes in fact the primary fuse holder of the fuze. This sleeve 32 is subject to the action of a spring 35 supported on one hand against a shoulder 36 of the sleeve 32 and, on the other hand, against a shoulder 37 arranged in the bottom of the bore 31. This spring 35 hence tends to return forward, that is to say towards the firing pin 15, the

primary fuse holder

32, 33, 34. However, a locking device holds this primary fuse holder 32-34 in secured position, spaced from the firing pin 15. This locking device comprises a ring 3% bearing elastic tongues 39 with thickened ends 40. This ring 38 is arranged in the upper portion of the bore 30. It has also a peripheral shoulder 41 enabling a bolt 42 to retain this ring 38 in secured position. The thckened ends of the elastic tongues 39 are capable of being engaged successively in two

grooves

43 and 44, spaced axially on the portion 33 of the primary fuse holder sleeve 32-34. A ring or bushing 45 subject to the action of the spring 46 surrounds the tongues 39. This bushing 45 has a portion 47 bored to a larger diameter than the end portion 48. As long as the portion 43 is at the level of the thickened ends 40 of the tongues 39, the latter cannot be disengaged from the groove 43. On the other hand, if following an axial displacement of the bushing 45, the portion 47 occurs opposite the thick end parts 40, the latter are elastically separable and can pass from the groove 43 into the groove 44 following a relative axial displacement between the

sleeve

32, 33 and the ring 38, and this specially on the departure of the shot. However, such an axial displacement of the ring 38 is prevented by the bolt 42 as long as the latter holds the shoulder 41 of this ring 33. This bolt 42 is in the shape of a piston slidably radially in a hole 49 arranged in the collar 7 of the part 2. This piston shaped 'bolt 42 is subject to the action of a leaf spring 50 tending to extract it from the hole 49 and thus to liberate the shoulder 41 of the ring 38. However, such a radial extraction movement of the bolt 42 is rendered impossible as long as the latter is supported by its rounded end 51 against the internal bore 52 of the cap 8. However, two cavities 53 and 54 (see FIGS. 9 and 10) are arranged in this bore 52 on both sides of the position occupied by the bolt 42 in FIG. 9, which position corresponds to the secured position of the fuze. This position corresponds therefore to the position of storage, transport or handling of the projectile. It will be understood without elaboration, on a study of FIGS. 9 and 10, that in causing an angular displacement, through a certain angle, of the cap 8, it is possible to bring either the cavity 52, or the cavity 54 opposite the hole 49, which enables the bolt 42 to escape radially to occupy the position shown in FIG. 10 which corresponds to the adjustment for delayed detonation after impact of the fuze. To this position shown in FIG. 10 corresponds the position shown in PIC}. 8 of the firing pin 15 and of its portion 18 especially with respect to passage 17.

Inside the sleeve 32 constituting the primary fuse holder is arranged a plunger or ram 55 slidable in this sleeve 32 against the action of a spring 56 tending to return the ram 55 away from the primary fuse 34. This ram 55 carries a second firing pin 57. In addition, a channel 58 is arranged in this ram 55 to enable the passage of the flame provided from the primary fuse 34 in the direction of a secondary fuse 59 arranged in the lower portion of the fuze.

A ball blocking mechanism 60 enables the primary fuse holder 32-34 and the ram 55 to be rigidly fixed to one another. In fact, the sleeve 32 of the primary fuse holder 32-34 has radial passages 61 of which the axis is directed towards the front of the fuze, from the center of the latter. On the other hand, the ram 55 has hemispherical recesses 62 intended to serve for partial housing of the balls 60. Through this fact, as long as the outer opening of the passages 61 is facing the bore 31 of the part 1 of the body of the fuze, the balls 60 are held partly in the ram 55 and partly in said passages 61, which locks the

parts

32 and 55 with respect to one another. However, a peripheral groove 63 is arranged in the upper portion of the bore 31, this groove being intended to receive the balls 69 after the fuse holder 32-34 has undergone displacement towards the front against the action of the spring 46. Such a displacement is produced on impact of the projectile against the target (see FIGS. 2 to 5).

The secondary fuse 59 is carried by a fuse holder 64 mounted to oscillate around an axle 65 parallel to the axis of the fuze, this axle being fixed between two plates 66 and 67 of a clockwork movement. A tong-shaped spring 68 engaged around the axle 65 tends to make the secondary fuse holder 64 pivot in anti-clockwise direction with respect to FIGS. 11 and 12 to bring the secondary fuse 59 into the axis of the fuze, so that it coincides with the position of the second firing pin 57 (see FIG. 12). However, this displacement of the secondary fuse holder 64 is prevented by a bolt 69 in the shape of a rod subject to the action of the spring 70, this rod 69 and this spring 70 being arranged in a housing 71 provided in the secondary fuse holder 64. One end 72 of this rod 69 is engaged in a hole 73 provided in the plate 66, rigidly fixed to the body of the fuze, whilst the other end '74 of this rod 69 cannot escape upwardly. In fact, this end 74 is supported against a toothed sector 75 mounted to oscillate around the same axle 65 and subject to the action of a tong spring 76 engaged around a tubular portion 77 rigidly fixed to this toothed sector 75. This spring 76 is engaged between a column 78 linking two plates 66 and 67 and a pin 79 borne by the toothed sector 75. It is only after angular displacement of the toothed sector 75 from the position shown in FIG. 11 to the position shown in FIG. 12 and slightly before the toothed sector 75 reaches this latter position that the end 74 can escape from this toothed sector and enable the spring 70 to extract the end 72 of the rod 69 from the hole 73, which then frees the secondary fuse holder 64 which is displaced by its spring 68 into the position shown in FIG. 12 in which the secondary fuse 59 occurs in the axis, that is to say in the detonation position in the fuze. The displacement of the toothed sector 75 is only possible after displacement in the direction of the nose of the fuze of the ram 55 and of the firing pin 57 which constitute a stop for the pin 79, in secured position of the fuze. After such a forward displacement of the ram 55, that is to say after the departure of the shot (see FIG. 2), the movement of the toothed sector 75 is braked by the escape wheel 80 and balance lever 81 of the clockwork movement mounted to oscillate around an axle 82. This escape wheel 80 is rigidly fixed to a pinion 83 with which the toothed sector 75 meshes by its teeth 84. The escape wheel 80 and the pinion 83 constitute a rotary drive mounted by axles on pivots 85 and 86 in plates 66 and 67.

The fuze described above is intended to be fixed in the front portion of a projectile by screwing the threaded portion 87 of the body of the fuze in a shell body for example, so that the detonator is close to the explosive charge of the projectile.

The operation of the fuze described above is as follows:

When the fuze is in inactive position, that is to say in position of storage or transport, the part 8 forming the ogive is adjusted into the position shown in FIG. 9, for which position the bore 52 prevents the bolt 42 from escaping radially, which causes the ring 38 to be held by its shoulder 41 in its extreme position towards the front of the fuze, the tongues 39 blocked by the ring 45 holding the primary fuse holder 32-34 in the position shown in FIG. 1, for which position this primary fuse 34 is separated from the firing pin 15 itself held in inactive position,.its. point being engaged in the passage17 in the angular position corresponding to FIG. 7, preventing any displacement of the pin 15 in the direction of the primary fuse 34. On the other hand, the ram 55 is kept blocked with respect to the sleeve 32 by the balls 60. Thus, the second firing pin 57 retains the toothed sector 75 in secured position by its pin 79. In addition, the rod 69 blocks the secondary fuse holder 64.

When an instantaneous explosion of the projectile on impact is required, the ogive 8 is brought into the angular position corresponding to the placing in coincidence of the cavity 54 with the hole 49. As soon as this operation has been effected, the bolt 42 escapes radially and frees the shoulder 41 of the ring 38. Moreover, the angular displacement of the ogive 8 brings the firing pin 15 and especially its portion 18 into the position shown in FIG. 6, that is to say into a position enabling passage of this portion 18 into the rectangular opening 17.

On the departure of the shot, in the muzzle, for example in a mortar, the ring 45 is driven rearward against the action of the spring 46 which enables the ring 38 bearing tongues 39 to be displaced also towards the rear, the ends 40 of the tongues 39 escaping from the groove 43 to be engaged in the groove 44. On emergence of the projectile from the muzzle, the spring 46 pels towards the front, the ring 45, which again locks the tongues 39 engaged then in the groove 44. The spring 35 also pushes back towards the front the fuse holder 32-34, driving with it the ram 55 which is rendered rigidly fixed to it by the balls 60 held engaged in the recesses 62 of the ram 55 due to the inclination towards the front of the passages 61 provided in the sleeve 32. The primary fuse 34 then reaches its armed position close to the point of the firing pin 15. Simultaneously, the second firing pin 57 frees the pin 79 rigidly fixed to the toothed sector 75, which enables the latter to commence its angular displacement under the action of its spring 76, which displacement is braked by the clockwork movement constituted by the pinion 83, the escape wheel 80 and the balance lever 81. The secondary fuse holder 64 and its actuating mechanism constitutes in fact a trajectory safety device. When the toothed sector 75 has accomplished its full displacement, the locking rod 69 having freed the secondary fuse holder 64, this secondary fuse 59 is brought into armed position (see FIG. 12) by its spring 68. If at this moment the projectile reaches its target, the protective cap 27 is thrust down (see FIG. 3) and the ram 14 is driven back towards the rear against the action of the spring 24 thereby driving the firing pin 15 which detonates the primary fuse 34. The flame is transmitted through the channel 58 to the secondary fuse 59 which, in its turn, detonates the transmission charge 6, the detonator 5 and the charge of the projectile.

If the projectile has to explode with delay after impact, the ogive 8 is displaced angularly with respect to the body of the fuze, so that the cavity 53 is brought opposite the hole 49 so as to permit escape of the bolt 42 into the position shown in FIG. 10. This adjustment brings the part 18 of the firing pin 15 into transverse position with respect to the rectangular passage 17 (FIG. 8), which prevents any possibility of displacement of the firing pin 15 in the direction of the primary fuse 34.

On firing of the projectile in the muzzle, and as explained previously, the ring 45 and then the ring 38 bearing tongues 39, come to be engaged in position opposite the groove 44. On emergence from the muzzle, the primary fuse holder 3234 is driven forward by the spring 35, so that the pin 79 is released by the second firing pin 57, which enables the operation of the trajectory safety device, that is to say which permits displacement of the toothed sector 75 and then the bringing into armed position of the secondary fuse 59. On impact of the projectile, the protective cap 27 is driven down (see FIG. 4) and the arm 14 is thrust towards the rear, the rod 88 of the firing pin 15 being buckled by this movement of theram 14, given that the. point ofthe firing pin 15 is held by the portion 18 arranged transversally with respect to the rectangular passage 17. Through this fact, no firing, no firing of the primary fuse 34 is produced. On the other hand, under the effect of this impact, the plunger or ram 55 is driven forwards against the action of the spring 56, the balls 60 being ejected into the groove 63 then serving as housing for them with the passages 61. Then, the spring 56 pushes back rearwards the plunger or ram 55 and the second firing pin 57 which causes the delayed detonation of the secondary fuse 59 (see FIG. 5).

The preceding description shows that this fuse is of simple conception enabling with a minimum of machined parts the obtaining of a very compact construction having high operational safety with the possibility of either instantaneous or delayed detonation of the charge of the projectile.

It will be apparent that various changes and modifications may be made in the embodiment described with out departing from the invention as defined in scope by the appended claims.

We claim:

1. Fuze for a nongyratory projectile, especially for firing by a mortar, enabling either instantaneous detonation of the projectile on impact or delayed detonation by prior adjustment of the fuze, said fuze comprising:

a fuze body,

a detonator,

a primary fuse,

a first firing pin arranged to be driven into said primary fuse for detonation on impact,

a primary fuse holder holding said primary fuse subject to the action of a first spring tending to thrust it axially in armed position towards said first firing p a locking device adapted to be unlocked under the effect of axial acceleration due to the departure of the shot and maintaining said primary fuse holder in spaced position from said first firing pin,

a detonator safety device comprising a secondary fuse,

a secondary fuse holder holding said secondary fuse transversally movable with respect to the axis of the fuze, a second spring tending to bring the secondary fuse opposite the detonator, clockwork means controlling the passage of the secondary fuse holder from a safety position to an armed position,

said clockwork means comprising a toothed sector subject to the action of a third spring, a stop axially displaceable on departure of the shot locking said toothed sector in inactive position of the fuze, a second firing pin forming said stop and arranged to detonate the secondary fuse once the latter is in armed position, a plunger axially slidable in the primary fuse holder against the action of a fourth spring and bearing said second firing pin, and a ball blocking mechanism arranged to fix said primary fuse holder and said plunger rigidly to one another as long as the projectile has not been subjected to an impact after the departure of the shot, and on such impact, to cause the escape of the blocking balls enabling the plunger and thus the second firing pin, to be driven in by their spring, with a time delay, against the secondary fuse.

2. Fuze according to claim 1, wherein the primary fuse holder is in the form of a sleeve capable of sliding axially in a bore of the fuze body having a peripheral groove, the balls of the blocking mechanism being normally housed partly in corresponding recesses of the plunger and partly in radial passages arranged in the said primary fuse holder sleeve, said peripheral groove being adapted to receive the balls after the impact of the projectile.

3. Fuze according to claim 2, wherein the axis of said radial passages is directed towards the front of the fuze, from the center of the latter, so that the balls remain clamped between the plunger and the radial passages until impact, under the action of said fourth spring.

4. Fuze according to claim 1, wherein the locking device of the primary fuse holder comprises an annulus bearing tongues with thickened ends, two axially spaced grooves being arranged in the outer wall of the primary fuse holder, said thickened ends being engaged in one of said grooves, a ring subject to the action of a fifth spring encasing said tongues so as only to permit passage of the tongues from one to the other of the two grooves on axial acceleration of the projectile on departure of the shot after relative axial displacement of the ring with respect to the annulus bearing the tongues.

5. Fuze according to claim 1, wherein the secondary fuse holder is mounted to oscillate around an axis parallel to the axis of the fuze, the toothed sector being mounted to oscillate around the same axis, a bolt formed by a rod subject to the action of a sixth spring being arranged in a housing of the secondary fuse holder so that one end of said rod is engaged in a hole in a part rigidly fixed to the body of the fuze and locks the secondary fuse holder in safety position as long as the other end of the rod is supported against a surface of the toothed sector.

6. Fuze according to claim 2, wherein the locking device of the primary fuse holder comprises an annulus bearing tongues with thickened ends, two axially spaced grooves being arranged in the outer wall of the primary fuse holder, said thickened ends being engaged in one of said grooves, a ring subject to the action of a fifth spring encasing said tongues so as only to permit passage of the tongues from one to the other of the two grooves on axial acceleration of the projectile on departure of the shot after relative axial displacement of the ring with respect to the annulus bearing the tongues.

7. Fuze according to claim 3, wherein the locking device of the primary fuse holder comprises an annulus bearing tongues with thickened ends, two axially spaced grooves being arranged in the outer Wall of the primary fuse holder, said thickened ends being engaged in one of said grooves, 21 ring subject to the action of a fifth spring encasing said tongues so as only to permit passage of the tongues from one to the other of the two grooves on axial acceleration of the projectile on departure of the shot after relative axial displacement of the ring with respect to the annulus bearing the tongues.

8. Fuze according to claim 2, wherein the secondary fuse holder is mounted to oscillate around an axis parallel to the axis of the fuze, the toothed sector being mounted to oscillate around the same axis, a bolt formed by a rod subject to the action of a sixth spring being arranged in a housing of the secondary fuse holder so that one end of said rod is engaged in a hole in a part rigidly fixed to the body of the fuze and locks the secondary fuse holder in safety position as long as the other end of the rod is supported against a surface of the toothed sector.

9. Fuze according to claim 3, wherein the secondary fuse holder is mounted to oscillate around an axis parallel to the axis of the fuze, the toothed sector being mounted to oscillate around the same axis, a bolt formed by a rod subject to the action of a sixth spring being arranged in a housing of the secondary fuse holder so that one end of said rod is engaged in a hole in a part rigidly fixed to the body of the fuze and locks the secondary fuse holder in safety position as long as the other end of the rod is supported against a surface of the toothed sector.

10. Fuze according to claim 4, wherein the secondary fuse holder is mounted to oscillate around an axis parallel to the axis of the fuze, the toothed sector being mounted to oscillate around the same axis, a bolt formed by a rod subject to the action of a sixth spring being arranged in a housing of the secondary fuse holder so that one end of said rod is engaged in a hole in a part rigidly fixed to the body of the fuze and locks the secondary fuse holder in safety position as long as the other end of the rod is supported against a surface of the toothed sector.

References Cited UNITED STATES PATENTS 1,547,599 7/1925 Lukens l0274 1,648,603 11/1927 Barker 10274 2,173,620 9/1939 Brayton 10274 2,324,192 7/1943 Brayton 102-74 2,977,882 4/1961 Vasse 102-74 2,999,461 9/1961 Apotheloz et a1. 102-75 3,115,094 12/1963 Simrnen 10 274 SAMUEL W. ENGLE, Primary Examiner U.S. c1. x12. 10276 R, 84