US3022733A - Rotary shell fuze - Google Patents

Description

Feb. '27,V 1962 H. JUNGHANS ETAL 3,0225733 RQTARY SHELL FuzE Filed April 24, 1959 4 sheets-sheet 1 NVENTORJ /fTjzfTzjsrm v Weef- Feb 27, 1952 H. JUNGHANS ETAL 3,022,733

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ROTARY SHELL FUZE Filed April 24, 1959 4 Sheets-Sheet 4 3,922,733 Patented Feb. 27,1962

3,022,733 RTARY SHELL FUZE Helmut Junghans, Rekenhof, Schramberg-Sulgen, Germany, and Rudolf Weber, Untere Schillerstr. Z4, Schramberg, Germany i 1 Filed Apr. 24, 1959, Ser. No. 80%,624

Claims priority, application Germany Apr. 25, 1953 The invention relates to a rotary shell fuze with sensitive impact ignition and a self-destroying device dependent upon the numbeiyof revolutions. The object of the invention is to produce a self-destroying system for which the weakest possible self-destroying spring is required, because in the known systems the objection has been found that a strong self-destroying spring, which as is known is fitted under pretension, becomes sluggish and fatigues in the course of time. The invention is characterized in that centrifugal levers of the self-destroying device are pivotable about axes which lie in a plane at right angles to Vthe axis of rotation of the fuze so that the inwardly directed radial arms of these levers can act in the tiring direction on a-pressure surface provided on the firing .pin when liberated by a timing mechanism arranged under and supporting them, andrthat above these centrifugal levers the spring ofthe self-destroying device cooperating with the backs of these levers is arranged in the fuze head, the adjustment of the self-destroying systern being such that in the initial safety position the center of gravity of a centrifugal lever lies above the plane determining its pivot axis which it traverses in the point of self-destruction.

The arrangement according to the invention of centrifugal levers between the pretensioned spring of the selfdestroying device and the firing pin, presents the advantage that the centrifugal force participates and assists in the forward thrust of the tiring pin and as a result the spring of the self-destroying device can be kept correspondingly weaker and its pretension be less, whereas in the known systems the/springs of the self-destroying device have to be stressed to the maximum limit of elasticity on account `of the limited structural space available. In the preferred embodiment of the invention Va centrifugal spiral is employed for'temporarily locking the centrifugal levers of the self-destroying device.. A simple form of construction of the fuze is obtained if the centrifugal levers of the self-destroying device are mounted with their pivot axles in open bearings which are formed by recesses in the fuze head and/or in the fuze base, and slotted plates are provided for laterally guiding these centrifugal levers, which plates cover the abovementioned recesses. The spring of the self-destroying device preferably cooperates with the centrifugal levers through the intermediary of a wide flanged sleeve, whereby the lever arms at these points of engagement are shorter than those acting on the firing pin, preferably one-third to one-quarter thereof.

According to another feature. of the invention the striker ram, instead of being rigidly connected with the firing pin in the striking direction, can be freely movable independently thereof and so constructed that in striking it encounters the centrifugal leversof the selfdestroying device, that is drives the firing pin into the ignition pellet indirectly through the intermediary of these levers. With this construction a certain delayed action is attained as compared with the normal constructionwhich is likewise possible in the present instance-where the striker ram and the tiring pin are rigidly interconnected. In the case of some purposes for which the shells here under consideration are used, a certain delay is desirable'when detonation is dependent upon impact, be-

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cause the shell should only explode after it has `penetrated the target t 1 Other features and advantages of the invention will become apparent from the several embodimentshereinafter described by way of example-from the drawings and from the claims.

The drawings showthese embodiments on a consider- Fre. 2 is atenten taken on une n n of FIG. 1;-

FIG. 3 is a part longitudinal section showing a different Way of mounting Ithe centrifugal levers of the selfdestroying device;

FlG. 4 shows the second forrn'of construction in longitudinal section on line IV--IV of FpIG. 5,'the functional parts being indicated in a similar manner to that used in FlG.,-l, and

FIG. 5 is a section taken on line V-V of FIG. 4. In the case of the firstembodiment illustrated in FIGS.' 1 and 2, the -fuze base is, designated by 10, the fuze cap by 11, the striker ram by 12, the firing pin by 13 which` i pierces an ignition pellet which is not shown in the drawing but which is to be screwed into the compartment 10a. In a recess 10b formed in the fuze base a centrifugal safety spiral 11i-'of known type is arranged andserves as bore-safe and projection-safe fuze. As long as the centrifugal lspiral 14 is Wound tightly around the core 15, the collar 15a of the winding core 15 rests on a thin disk \16 above the centrifugal spiral 14. The disk 16`serves for protecting the centrifugal spiral against damage under high tiring pressures and may therefore be omitted under favorable circumstances. The firing pin 13 is inserted in the Winding core. 15 until its collar .13a rests on the core. lt can be seen that the upper end 13b of the pin shaft is free in the bore 12a' ofthe striker ram 12; consequently movement of the striker ram 12 in the piercing direction cannot be directly transmitted to the firing pin. The object of this arrangement will be Vhereinafter' described. The inwardly projecting annular step 10c extendsfrom the recess lllbjin upward direction; which' together with the peripheral surface of the recess 10d serve as'supporting bearing for the centrifugal levers 18 ofthe selfdestroying device. The lateral guiding of these centrifugal levers 18 is effected partly by slots 105e formed in the edge of the fuze base 10 and partly by guide slots 19a in a guide plate 119 fitted in the upper edge of the fuze base 10. l

The arms 18a of the centrifugal levers 1S project radially inwards and their noses 18h can rest on the upper side 15b of the winding core 15 rigidly connectedvwith the tiring pin 13. At the same time the backs 18e' of the leverl arms 18a are located in the striking range of the end face 12b vof the striker ram 12. Another arm 18d of the centrifugal levers 18 rests on the disk 16 which is inserted between the collar 15a on the windin core and the centrifugal spiral 14.

The spring 20 of the self-destroying device is fitted in a bore 11a in the fuze cap and the sleeve 7.1 is guided in a widened portion 11b of this bore. This sleeve 21 has a wide flange 21a which bears against the pressure points or projections 18e v,under the pressure exerted by the It willbe seen from the drawingthat the lever arms at these pressure points are much shorter than the effective lever arms with which the centrifugal levers engage the primer.

The construction, arrangement and adjustment of the centrifugal levers is so chosen that in safety position (see FIG. 1, solid lines) the center of gravity of the levers in the positions S1 is located above the imaginary plane extending through the pivot axles 17 of the levers and in such a manner that the initial speed of rotation of the shell is still suicient to overcome in conjunction with the centrifugal force acting on the centrifugal levers, the force of the pretensioned spring of the self-destroying device and to lift the sleeve 21 slightly.

During this stage the centrifugal spiral 14 can fly out into the position shown in broken lines so that the disk 16 loses its support.

As the number of revolutions decreases, the system enters the state of equilibrium; the position of the center of gravity is then designated by S2. In the event of irnpact in this state, the striker ram 12 would first be forced inwardly independently of the ring pin 13, its striking surface '12b would then come into contact with the backs of the levers at 18C, carry these along and through their intermediary when the noses 18b come into contact with the winding core at 15b, drive the tiring pin 13, which is rigidly connected therewith, into the ignition pellet. Thereby three forces act jointly, namely the force caused on the striker ram 12 by the impact, the centrifugal force acting on the levers after passing the state of equilibrium and the force of the spring of the self-destroying device.

If the shell misses its target, the state of equilibrium between the centrifugal force acting on the centrifugal levers of the self-destroying device and the pretension of the spring of self-destroying device continues to change as the number of revolutions of the shell decreases, in the sense that the centers of gravity of the centrifugal leversv 18 are forced out of the state of equilibrium S2 and the effective centrifugal forces can force the levers 18 downwards as the lever arm increases in length, so that, shortly after leaving the position of equilibrium, their noses 18b come into contact with the winding core 15 and, assisted by the spring 20- of the self-destroying device, drive the firing pin 13 into the ignition pellet with increasing speed.

As can be seen from FIG. 3, the centrifugal levers of the self-destroying device, which are here designated by 28, instead of being pivotally mounted on pins vor axles, are provided with rounded supporting arms 28a. With the aid of these supporting arms they bear partly on the bottom surface 10g of slots `10g worked in the edge of the fuze base 10 and partly against the recess 111ein the fuze cap 11.

In the embodiment illustrated in FIGS. 4 and 5, the self-destroying system of the first embodiment is retained. The dilference is that the impact does not act indirectly through the intermediary of the centrifugal levers of the self-destroying device 18, but directly. That is, the striker mushroom 50'is rigidly connected with the firing pin 51 in: the direction of thrust. Instead of the winding core 1S of the rst form of construction, the firing pin is in this instance provided with a collar 51a which is recessed at 51b so as to receive a half-disk 52. This half-disk 52 is in turn introduced through a lateral slot 53a in the winding sleeve 53 so far that the centrifugal band 14 is wound smoothly on the sleeve 53. This arrangement is known per se. The case in question is constructed so that the centrifugal levers of the self-destroying device also bear directly ony the centrifugal band winding without any disk being interposed.

The self-destroying arrangement operates in the same manner as in the first embodiment, that is, after the initial flying out of the winding band 14 and of the safety half-disk 52, the centers of gravity of the levers, when the target isV missed and the number of revolutions of the shell decreases to a predetermined figure, pass out of the l safety position S1 through their labile central position (not shown) and continue to move, the force of the spring of the self-destroying device being supplemented by the centrifugal force, until finally their arms 18a contacting the end face 51C of the ring pin 51 entrain this until the ignition pellet is pierced. The responsive blow takes place without the cooperation of the centrifugal levers 18 in that the centrifugal force acting on the striker mushroom 50 is directly imparted to the tiring pin 51.

In the second embodiment only two centrifugal levers are provided instead of three; these levers are laterally guided in the slotted plate 54, FIG. 5.

We claim:

1. A rotary shell self-destroying fuze comprising a base havingl a recess therein and a central axial opening, a fuze cap mounted on the base and having a bore therein, a core mounted in the central axial opening and having an axial bore therein, a ring pin in the fuze cap and extending through the axial bore in the core, a guide plate in the fuze cap and having a plurality of spaced and radially arranged slots therein, a centrifugal lever rotatably mounted in each slot with a pivot point near the outer peripheral edge of the fuze base, each lever having an upper arm and a projection and a lower arm, a safety coil spring normally coiled around the core and in this position forming an abutment for the lower arms of the centrifugal levers, and a sleeve mounted in the bore of the fuze cap and having a flange to contact the projections of the levers, said spring flying radially due to centrifugal force to pass from under the levers to force the upper arms of the levers to contact the core to permit the sliding actuation of the firing pin.

2. A yfuze according to claim 1, in which the centrifugal levers are mounted in the slots with play, and guided by the slotted plate inserted in the fuze.

3. A fuze according to claim l, in which an inner shoulder is mounted in the fuze base serving as a bearing for the centrifugal levers, and in which pivot pins are provided one for each centrifugal lever.

4. A fuze according to claim 1 in which the radial slots provided in the guide plate of the fuze base serve as lbearings for the centrifugal levers and the slots being covered on one side Vby the inner wall of the fuze cap.

5. A fuze according to claim 1, in which the lever arm between the pivot point of each centrifugal lever and the engagement point of the sleeve with the projection being smaller than the upper arm of the centrifugal lever and ranging from one-third to one-quarter of the length of the latter. y

6. A 4fuze according to claim l, in which a cover disk is provided on the coil spring to support the centrifugal levers by contact with the lower arms when the spring is tightly wound around the core.

7. A fuze according to claim 1, in which a striker ram is provided in the cap for the firing pin and contacting the projection of each of the centrifugal levers.

References Cited in the file of this patent UNITED STATES PATENTS 1,3'66,l48 Zeid'ler Jan. 18, 1921 2,014,393 Mathsen Sept. 17, 1935 2,782,717 Burri Feb. 26, 1957 2,790,390 Baker Apr. 30, 1957 2,8t18,812 Shenk Jan. 7, 1958 2,873,678 Koonz Feb. 17, 1959 2,924,176 Neuwinth Feb. 9, 1960 FOREIGN PATENTS 61,219 Denmark July 26, 1943

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