US3616756A

US3616756A - Time fuze for projectiles

Info

Publication number: US3616756A
Application number: US801705A
Authority: US
Inventors: Robert Simmen; Francis Liengme
Original assignee: Mefina SA
Current assignee: Mefina SA
Priority date: 1968-04-04
Filing date: 1969-02-24
Publication date: 1971-11-02
Anticipated expiration: 1988-11-02
Also published as: NO125066B; NL164957C; DE1814546C2; ES362080A1; BE724075A; DE1814546A1; BR6804966D0; DK133521C; NL164957B; SE353790B; GB1199707A; FI53629B; DK133521B; FR1592296A; CH475544A; AT296089B; FI53629C; NL6817874A

Abstract

TWO SEPARATE TRAINS OF SAFETY ELEMENTS, ONE BEING AN INERTIAL SAFETY MECHANISM THAT RELEASES THE CLOCKWORK ONLY WHEN THE PROJECTILE IS ACCELERATED, EACH PREVENTS THE PRIMER CHARGE FROM BEING MOVED INTO ALIGNMENT WITH THE FIRING PIN UNTIL THE PROJECTILE IS ACCELERATED AND, IN THE CASE OF THE NON-INERTIAL TRAIN, UNTIL THE CLOCKWORK RUNS.

Description

R. SIMMEN EFA!- TIME FUZE FOR PROJECTILES Nov. 2, 1971 7 Sheets-Sheet l Filed Feb. 24, 1969 NGV. 2, 1971 R, SlMMEN EI'AL 3,616,756

TIME FUZE FOR PROJECTILES Filed Feb. 24, 1969 7 SlleeLs-Shee?l 2 l Flo @a 9 A Fm n f l! C i" C Er l: 55 WE NOV. 2, 1971 R S|MMEN ETAL 3,616,756

TIME FUZE FOR PROJECTILES Filed Feb. 24. 1969 7 Sheets-Sheet l NOV. 2, 1971 R, SlMMEN ETAL 3,616,156

TIME FUZE FOR PROJECTILES Filed Feb. 24. 1969 7 Sheets-Sheet 4 319-115@ 24 l 2' 3a c@ I je I /5 -ss N n da skt; 2' It: Q l f 32 A, .wir

im UV R. SIMMEN ETAL IME FUZE FOR PROJECTILES Nov. 2 1971 7 Sheets-Sheet 5 Filed Feb. 24.Y 1959 Nov. 2,` 1971 RSMMEN UAL 3,616,156

. TIME FUZE FOR PROJECTILES Filed Feb. 24. 1969 7 sheets-sheet 6 NGV. 2, 1971 R, slMMEN EI'AL TIME FUZE FOR PROJECTILES 7 sheets-sheet 1 Filed Feb. 24. 1969 United States ILS. Cl. 102-76 11 Claims ABSTRACT 01E THE DISCLOSURE Two separate trains of safety elements, one being an inertial safety mechanism that releases the clockwork only when the projectile is accelerated, each prevents the prnner charge from being moved into alignment with the tirlng pin until the projectile is accelerated and, in the case of the non-inertial train, until the clockwork runs.

The invention relates to a fuze for projectiles, the fuze incorporating one or more safety devices to prevent accidental detonation of the projectile.

Among the problems commonly associated with thes'e fuzes are overstraining or jamming of the fuze While it 1s being set, accidental arming of the fuze, and explosion of the projectile when it is accidentally dropped.

The purpose of the invention is to provide a fuze that solves these three problems, and in so doing ensures that a projectile incorporating the fuze of the invention is detonated only at the desired moment.

The invention will be described, with reference to the gures of the accompanying drawings, wherein:

FIG. 1 is a side view, partly in cross-section, of the time fuze of the invention;

FIG. 2 is a view taken along line M-M of FIG. 1;

FIG. 3 is a side view, partly cut away, of the fuze clockwork mechanism;

FIG. 4 is a view taken along line A-B of FIG. 3;

FIG. 5 is a view taken along line C-C of FIG. 3;

FIGS. 6 and 7 are views respectively taken along lines D-D and E-E of FIG. 3;

FIG. 8 is a side view, similar to that of FIG. 3, partly cut away, taken along a plane passing through the axis of the ring pin;

FIG. 9 is a side view, similar to that of FIG. l, showing the fuze armed Iafter the proejctile has been red;

FIG. 10 is a view taken along line M-M of FIG. 9;

FIG. 11 is a side view corresponding to that of FIG. 3, showing the fuze armed;

FIG. 12 is a side view corresponding to that of FIG. 8, showing the fuze at the instant it sets off the primer charge;

FIG. 13 is a view taken along line AB of FIG. 1l; and

FIG. 14 is a view taken along line DLE of FIG. 11.

The mechanical time fuze, or fuse (the preferred spelling for a mechanical fuse), of the invention is particularly suitable for mounting in non-spinning projectiles, and belongs to the category of fuzes that incorporate means for making the projectile transport safe, bore safe, and trajectory safe. The fuze comprises abody 1 in which a clockwork, or time mechanism, indicated generally by the reference number 2, is mounted. This clockwork is wound up by a fuze setting disc 3. The lower part of the fuze body 1 incorporates a threaded hole 4 for a detonator, not shown. A stop 5 is fixed at the top of the fuze body, of which the upper part embodies a cylindrical projection 52 that mounts a cap y6 forming part of the ogive of the projectile. The cap is angularly movable with respect to the fuze body, and is held axially to the latter by -a steel wire arent O 7 Iwhich is bent zigzag so that it partly occupies a groove 53 of the fuze body 1 and partly a groove 54 in the cap 6. A screw 55 in a threaded hole 56, extending radially into the cap 6, holds the wire 7 in its active position, for keeping the cap axially in place. An O-ring gasket 57 is held in a groove 58 of the cap. The cap also has a stop y8 which cooperates with the stop 5- to limit the angular movement of the cap 6 between the one side of the stop 5, corresponding to the minimum fuze setting, and the other side, corresponding to the maximum setting.

The cap 6 carries a split pin t9 mounting a catch, or coupler, 10 that is free to pivot about a pin 11 transversely held in the pin 9. A leaf spring 12, carrying weights 13, is lixed to the cap 6 by rivets 14.

The clockwork 2 comprises a series of

plates

15, 16, 17, and 1'8 (see FIG. `8) connected together by

spacers

28 and 59. It also includes a central spindle 19, to which are rigidly fixed the fuze setting disc 3, a cam 20,

spacers

21 and 22, a tightening nut 23, and a supporting plate 24. The main wheel 26 of the clockwork movement is frictionally held between the plate 24 and an elastic washer 25 mounted by this plate, which washer presses the main wheel against the plate. One end of a spiral spring 27 is fixed to the spindle 19 and the other end to the spacer 28. The main wheel 26 transmits the turning force of this spring to the

wheels

29, 30, and 31 of the clockwork, the wheel 31 being the escapement wheel, which cooperates with the balance 32 of the clockwork, as shown in FIG. 6, the wheel 31 and the balance 32 together constituting the escapement mechanism.

Arranged between the

plates

17 and 18 is the pivotal support 41 of a primer charge 45, which latter is ignited by the tiring pin 38, leading to the detonation of the projectile. The support 41 is mounted free to turn about an axle 60, seen in FIG. 3. A spring 43 tends to cause the support to turn clockwise, as viewed in FIG. 7. Two trains of safety elements, however, hold the support in its iixed position, shown in FIG. 7. The first train (see FIGS. 3 and 4) includes a 'bolt 36 held by a spring 35 against the periphery of the fuze setting disc 3, which latter embodies a notch 3a, 2b that permits the bolt 36 to turn. The bolt is carried by a spindle 33 which also carries a retaining finger 37 that holds the support 41 of the primer charge 45 in place, as seen in FIG. 7. The second train of safety elements comprises an inertial safety mechanism consisting ofl the parts 4-6 to 51, illustrated in FIGS. 3, 4, and 7. The mechanism incorporates a retractable pin 48, the lower extension of which holds the support 41 in its fixed position, as does the finger 37. This pin embodies two axially spaced grooves 61 and 62. Around the upper end of the pin 48 is placed a sliding bushing 46 having elastic claws 63, which engage the groove 61 or 62, depending on the position of the bushing. A sleeve 47, serving as a counterweight, surrounds the claws 63, and permits the latter to leave the groove 61 and to enter the groove 62, after the bushing 46 has moved axially with respect to the pin 48, only when the sleeve 47 also moves axially. A compression spring 49 normally prevents this movement of the sleeve 47 during axial acceleration, since the lower end of this spring presses against a shoulder `64 of the pin 48 and the upper end against a shoulder I65 of the sleeve 47. A second compression spring 50, surrounding the lower part of the pin 48, keeps the pin raised. A collar 51 held at the lower end of the pin limits the upward movement of the pin, when the inertial safety mechanism is released, by striking the plate 17` The inertial safety mechanism, consisting of the parts 46 to 51, is partly housed within a tube 66 that 'also constitutes a spacer between the

plates

15 and 16.

The bushing 46 has an outer groove 67 that accepts the periphery of the cam 20 in its :fixed position.

As shown in FIGS. 3 and 6, the pin 48, near its base, incorporates a collar 68, which has a greater diameter than any other part of the pin and which lies in the path swept by the balance 32. For this reason, the collar, when it is in its fixed position, illustrated in FIG. 3, prevents the clockwork from running.

The ring pin 38, seen in FIG. 8, is guided between the plates and 16. It carries a collar 69 having a face 70 in the shape of a truncated cone. The tiring pin is biased by `a compression spring 39 tending to thrust it downwards. It is held in its xed position by a small plate 40 that is mounted free to pivot by a pin 71. This plate has a sloped face 72 that supports the face 70 of the collar 69. The sloped face 72 and the face 70, in the shape of a truncated cone, cooperate to cause the plate 40 to tend to pivot clockwise, as viewed in FIG. 6, since the tiring pin 38 is constantly urged downwards by the spring 39. The plate 40 is prevented from turning, however, because its end 73 is stopped by the spindle 33 of the bolt 36. The spindle embodies a groove 34 located substantially in the plane of the plate 40, so that when the groove is positioned opposite the plate end 73, the plate is free to turn, thereby releasing the firing pin 38.

The

notch

3a, 3b in the fuze setting disc 3 has a profile that forms two successive supports for the bolt 36, after the disc 3 has been turned by the clockwork. The rst support 3a (see FIGS. 4 and 13) holds the bolt in that position in which the retaining finger 37 for the support 41 of the primer charge 45 frees the support. The primer charge is then moved into the armed position opposite the firing pin 38. The second support 3b corresponds to an angular position of the bolt 36 and its spindle 33 in which the groove 34 is positioned opposite the end 73 of the plate 40, whereby the latter is now free to turn and to release `the firing pin 38, detonating the projectile.

The catch 10 (see FIGS. l, 2, 9, and l0) actually serves as a retractable coupler between the member for setting the fuze, consisting of the cap 6, and the fuze setting disc 3. As long as the fuze is not set, the catch 10 is held in its position in which it makes a positive connection between the cap and the disc. After the fuze is set, the catch 10 can be retracted to uncouple the cap 6 from the disc 3 only under the effect of an axial acceleration of the projectile causing the weights 13 of the leaf spring 12 -to bend the latter downwards against the catch 10, as shown in dot-dash line in FIG. 9.

The fuze described operates in the following manner: Before the fuze is set, the catch 10 holds the fuze setting disc 3 in the position illustrated in FIG. l. The catch cannot turn about the pin 11 because of the stop 5. Nor can the inertial safety mechanism 46 to 51 lbe armed, since the projection 74 of the edge of the cam 20 enters the groove 67 of the bushing 46 (see FIGS. 3 and 4). preventing any axial movement of the latter. For this reason, the movable support 41 of the primer charge 45, as well 'as the balance 32 of the

escapement mechanism

31 and 32, remains locked in the nonset position.

The fuze is set by turning the cap 6 against an amount of friction sufficient to ensure that the cap is held stably in any angular position of the latter with respect to the body 1. As the cap is turned, the fuze setting disc 3 is rotated by the catch 10 held by the split pin 9, the catch thus being moved away from the stop 5. The rotation is also transmitted to the cam 20, the

spacers

21 and 22, the nut 23, the plate 24 and its washer 25, and to the central spindle 19 of the spiral spring 27. This movement of the spindle 19 winds up the spring 27 to a certain tension. The main wheel 26 cannot turn with the spindle 19, since it is held by the

wheels

29 and 31 and by the balance 32 locked by the collar 68 of the pin 48. The plate 24 and the elastic washer 25 consequently slide over the main wheel. While the cam turns, the cam projection 74 leaves the groove 67 of the bushing 46.

At the moment that the projectile is fired, the axial acceleration of the projectile while the latter is still in the piece of ordinance results in the weights 13 bending the leaf spring 12 downwards, so that the catch, or coupler, 10 is pivoted, freeing the fuze setting disc 3, as shown in FIG. 9. At the same time, rst the sleeve 47, acting as a counterweight, and then the bushing 46 are pushed rearwards, compressing the spring 49. The elastic claws 63 of the bushing `46 now can leave the groove 61 to enter the lower groove 62 of the pin 48.

After the projectile has left the piece of ordinance (and therefore is no longer axially accelerated), the sleeve 47 holds the bushing 46 at the position of the pin groove `62, the

part

46, 47, and 48 thus acting as a lock.

The group of parts 46, l47, 48, and 49 is raised by the compression spring 50 until the collar 51 strikes the plate 17. As shown in FIG. 11, this movement of the pin collar frees the balance 32 of the

escapement

31 and 32, so that the spiral spring 27 can drive the clockwork.

The upward movement of the pin 48 also frees the nose 142 of the support `41 (see FIG. 7), and the latter, driven by the spring 43, turns until its face 41a strikes the retaining nger 37 carried by the spindle 33 of the bolt 36, the face 41a and the nose 42 respectively occupying the positions 41a and I42.

The projectile is now in flight; and the fuze clockwork continues to run, the fuze setting disc 3 turning in the direction of the arrow of FIG. 4. When the bolt 36 strikes the support 3a of the

notch

3a, 3b, its spindle 33 turns sufficiently so that the retaining linger 37 frees the support 41, which pivots and moves the primer charge 45 under the point of the firing pin 38.

Since the disc 3 continues to turn, somewhat later the bolt 36 strikes the second support 3b of the disc 3, the spindle 33 turning through an additional angle, whereby the groove 34 is moved to a position opposite the end 73 of the plate 40 (see FIG. 14), which latter now pivots clockwise and frees the firing pin 38 to set off the primer charge 45. In turn, the detonator xed in the threaded hole 4 is tired, exploding the projectile.

The fuze just described ensures the utmost safety in operation, because the fixed position of the movable support 41 for the primer charge 45 is undertaken by two separate trains of safety elements.

-Even if the projectile should fall on its base, the sudden movement of the weights 13 against the catch, or coupler, '.10 cannot cause the latter to turn, since it will strike the stop 5. Moreover, the friction drive between the spindle 19 of the spring 27 and the main wheel 26 prevents the clockwork movement from being overstrained or jammed while setting the fuze.

The mechanical time fuze of the invention is particularly valuable for non-spinning projectiles, although it is, of course, perfectly applicable to a spinning one.

Although the preferred embodiment of the invention has been described, the scope of, and the breadth of protection afforded to, the invention are limited solely by the appended claims.

What is claimed is:

1. A time fuze, particularly suitable for a non-spinning projectile, incorporating means for making the projectile transport safe, bore safe, and trajectory safe, including a spring-loaded firing pin, a movable support, a primer charge carried by said support and movable therewith from an inactive position, in which it cannot, to an active position, in which it can be struck by said ring pin, the trajectory-safe means including a clockwork for controlling the operation of said firing pin and for preventing movement of said primer charge to its active position for a predetermined time after the projectile has been shot, an escapement mechanism incorporated by said clockwork, a body for the fuze, a fuze setting member movable angularly with respect to said fuze body, a fuze setting disc turned by said fuze setting member, a clockwork drive spring, a clockwork drive spindle rotationally rigid with said disc and subject to the torque of said spring for turning said spindle when the fuze is armed, and wherein the improvement comprises a retractable coupler movable between an active position, for positively connecting together said fuze setting member and disc, and an inactive position, means for holdingy said coupler in its active position as long as the fuze is not set, and for Permitting said coupler to move to its inactive position only when the fuze is set and the projectile is being axially accelerated, means rigidly carried by said fuze setting member for holding said coupler, a stop in said fuze body for preventing movement of said coupler from its active position as long as the fuze is not set, a notch in said fuze setting disc for receiving said coupler in its active position, an elastically supported weight responsive to the axial acceleration force of the projectile for moving said coupler from its active to its inactive position, in which said coupler is moved out of said disc notch, when the fuze has been previously set, said trajectory-safe means further including first and second separate trains of safety elements for determining the position of said movable support, said rst train including a bolt, resilient means for holding said bolt in contact with the edge of said fuze setting disc, said disc notch being embodied in the edge of said disc and cooperating with said bolt, a spindle rotationally rigid with said bolt for mounting the latter free to move through an angle determined *by said disc notch, a retaining finger carried by said bolt spindle and moving therewith, for cooperating with said primercharge support; said second train consisting of an inertial safety mechanism including a retractable pin movable between an unarmed position, for holding said support in the inactive position of said primer charge, and an armed position, in which said support is no longer so held, and resilient means for holding said inertial safety mechanism unarmed.

2. The fuze as defined in claim l, including a cam carried by said clockwork drive spindle and turning therewith for locking said inertial safety mechanism as long as the fuze is not set.

3. The fuze as defined in claim 2, including a plate for holding said iiring pin in its loaded position, means for mounting said plate to move from a first position, in which said iiring pin is held loaded, to a second position, in which said firing pin is released, said bolt spindle cooperating with said plate to prevent the latter from moving from its iirst position, a groove in said bolt spindle for permitting said plate to move its second position as soon as said disc notch permits said bolt to move angularly a sufficient amount.

4. The fuze as defined in claim 3, wherein said plate and said iiring pin each have a face that are in mutual abutment, when said plate is in its first position, for tending to cause said plate to move to its second position.

5. The fuze as defined in claim 4, wherein said plate mounting means mounts said plate to pivot from its first to its second position.

6. The uze as defined in claim 3, wherein said retaining finger prevents said support from moving said primer charge to its active position and including iirst and second supports incorporated by said disc notch for successively supporting said bolt against further angular movement, said first support determining an angular bolt movement that moves said retaining linger so as to release said support therefrom, whereby the latter is free to move said primer charge to its active position, said second support determining a further angular bolt movement in which said bolt spindle groove frees said plate to move to its second position.

7. The fuze as defined in claim 6, including a balance incorporated by said escapement mechanism, and a train of wheels, including an escapement wheel forming a part of said escapement mechanism and driving said escapement balance, and a main wheel driven by said clockwork drive spindle for driving said train of wheels, and wherein the improvement comprises that said main wheel is in frictional engagement with said clockwork drive spindle.

S. The fuze as defined in claim 7, including a support rigidly connected to said clockwork drive spindle and turning therewith for carrying said main wheel, and an elastic washer for pressing said main wheel against said support, whereby said main wheel is held in frictional engagement with said clockwork drive spindle.

9. The fuze as defined in claim 7 wherein said retractable pin in its unarmed position prevents movement of said balance and in its armed position frees said balance.

10. The fuze as defined in claim 9, wherein said retractable pin has upper and lower longitudinal spaced grooves, a bush for moving longitudinally along said retractable pin, a plurality of elastic claws on said bush for engaging in one of said pin grooves in dependence on the position of said bush, a sleeve acting as a counterweight and surrounding said bush claws and free to move longitudinally along said retractable pin under the effect of axial acceleration of the projectile, for preventing movement of said bush, and for holding: said bush claws in said upper pin groove, except when said sleeve is caused to move longitudinally along said retractable pin under the effect of projectile axial acceleration, and wherein said resilient means of said inertial safety mechanism holds said sleeve in that position in which said bush claws engage said upper pin groove until the projectile is axially accelerated, and further resilient means for causing movement of said retractable pin from its unarmed to its armed position after said sleeve has moved longitudinally.

11. The fuze as defined in claim 10, including an outer groove incorporated by said bush, and a peripheral part incorporated by said cam for engaging in said bush outer groove to prevent positively longitudinal movement of said bush as long as the fuze is not set, said cam peripheral part being moved out of said bush outer groove when the fuze is set.

References Cited UNITED STATES PATENTS 2,446,745 8/1948 Delay 102-71 2,911,915 1l/1959 Gibbs et al 102-71 BENJAMIN A. BORCHELT, Primary Examiner T. H. WEBB, Assistant Examiner Us. C1. XR. 1oz-71, 75