US1666672A - Percussion fuse for projectiles subjected to a rotary movement around their axes during their trajectory - Google Patents

Description

Apnl 17, 1928. 1,666,672

A. VARAUD PERCUSSION FUSE FOR PROJECTILES SUBJEC'IED TO A ROTARY MOVEMENT AROUND THEIR AXES DURING THEIR TRAJECTORY Filed June 8, 1926 2 Sheets-Sheet l MTV. v I, .1

T a 2 e n 9 5% l 0 f F Z.

va-i117. 1928.

TARY RY A. VARAUD USE FOR PROJECTILES SUBJECTED TO A B0 OUND AXES DURING THEIR TRAJECTO June 8. 1926 THEIR Filed PERCUSSION F MOVEMENT AR 2 Sheets-Sheet 2 Patented Apr. 17, 1928.

,UVNVITED STATES 1,666,672 PATENT err-"leg v ANDRE VARAUI), OF GENEVA, SWITZERLAND PERCUSSION FUSE Eon PROJEGTILES SUBJECTED' TO A ROTARY MOVEMENT ABOUNI) Tnnm AXES DURING THEIR. TRAJ'ECTORY.

Application ru e June e, 192 Serial No.

The invention refers to percussion fuses for projectiles'subjected to a rotary move ment around their axis during their trajectory.

Up to this date the percussion of these fuses has been controlled by impact either by an inertia effect projecting one of two ignition members (striker or primer) one upon the other, or by the axial'return mo tion of a striker disposed at the outside of the. fuse point and normally retained by means of a pin or a spring in its position projecting from the fuse point so as to touch the butt or aim before the body of the fuse does so.

In the case of the first described arrangement it is practically observed'that the inertia effect counted on does not produce itself with such an energy and rapidity as will be suflicient to cause percussion whenever the projectile arrives at the butt in a rather tangential direction with the ground as will. often occur in firing with a very straight trajectory or whenever the projectile falls laterally on theibutt in'which case the inertia efiect is produced too late for rendering the firing really effective if the impact takes placeon a network of barbed or steeple wire, in very humid or marshy grounds, or even on a pond or the like, because the projectile in such a case is buried .too'deepbefore it bursts.

In the second case referred to, it is possible by a suflicient reduction of the pin or of the spring to increase the sensibility of the fuse so that the projectile bursts fairly near the surface of the ground, even if the encountered obstacle offers but comparatively little resistance, but this increase of sensibility is obtained at the expense of safety in the use of such fuses. In fact it may be stated that in practical use not only is the transport of such-fuses very dangerous, but that even a very slight error in the caliber of the pin or in regulating the spring may cause the striker to be returned by the resistance of the air and to thereby provoke a premature bursting of the projectile a number of meters after its start.

Independently of this defect it is observed in both the cases alluded to that a great number of failures occur in the firing with a very straight trajectory, which are :due to the'fact that upon'the impact thepro- 'jectile simply grazes the ground and re- 114,428, and in Switzerland June 9, 1925. I

obstacle, an event Which-often produces a torsion of the bar of the striker and prevents it from freely sliding towards the prlmer. o i

In order toovercome these inconveniences, that is to say inorder to produce a percussion fuse which, on the one hand, fully Warrants entire safety during transport and during firing, and, onthe other'hand, secures on the impact a sufficiently instantaneous percussion for causing the bursting .of the projectile right on theisurface of the round no matter what be the nature of the o stacle met with and thepositionof the projectile on. its arrival, the fuse according to this invention is made to comprise at least one member subjected tolthe action ofthe centrifugal power and laterally projecting from the body .of theufuse and remaining in this position regardless of the resistance of the air during the entire trajectory and which at the end of the latter will provoke an instantaneouspercussion immediately as the least possible resistance displaces it from this projecting position. v j

The drawing shows byway of example a working form of the invention;

Fig. l is an elevation showing the fuse provided with its protecting cap.

Fig. ,2 is a similar view representing the fuse with its protecting cap taken off.

Figs. 3 to 6 are axial longitudinal sections showing the fuse respectively before firing, at the moment of firing,.at the momentwhen the projectile traverses the spires in theicannon, during the trajectory and finally atthe moment of the impact.

Figs. 7 8 and 9 are transverse sections respectively on the lines VII-VII of Fig.

2, VIIIVIII of Fig. 4 and-IX-IX of Fig. 6.

The Figs. lOto 12 are detail views.

From the Figs. 1 to 6 it willbe seen that the fuse is made from three portions, a, b, and c, screwed one into the other.

The striker p is mounted axially movable in the axis of the fuse and .is guided by means of a sleeve made in one piece with-the part a. This striker'is normally submitted .to the action'of a percussion spring 7' which is put under tension in the course of manufactureof the fuse and is maintained inthis position until the moment of the impact by means of a swivelling lever m provided at its free end with a portion m having an inclined plane adapted to enter av notch 12 of corresponding shape provided for in the striker 12.

It is easily to be conceived that this notch with an inclined surface serves on the one hand to prevent each and every axial displacement of the striker in the direction towards the primer when the lever m is in its locking position, and on the other hand is adapted to facilitatethe movement of this lever by the action of the percussion spring 7' as soon as it is freeto the action of the centrifugal power. In order to hold the portion m of this lever m engaged in thenotch p of the striker p a locking sleeve 9 is made use of in the circular hollow g of which enters a pin m fixed on tlfe lever m lVhen at rest this sleeve .9 is prevented from any axial displacement by two cylindrical stoppers n or centrifugal safety members which are provided for in diametrically opposed positions and lodged radially with regard to the axis of the fuse. The inner ends of these stoppers come to bear against the periphery of the locking sleeve 9 whilst its other ends rest on the internal portions of lever Z whose function will be explained later on.

These diametrically opposed levers Z are arranged in a diametrical slit provided for in the cap I) and are adapted to swing on a pin 9 fixed in the cap 1).

Between two shanks Z of each of the levers Z there is provided a release finger (Z also oscillating on said pin 9.

Each finger (Z is operated by its lever Z by means of a spring 6 lodged between the shanks Z The part (Z of this finger remains in mesh with acircular groove of the sleeve 9 whilst the notch (Z comes to bear against the free end of spring e.

The operation of this embodiment of invention is as follows:

Before beginning with the firingythe protecting cap 71 is removed.

At the departure of the projectile, a cylinder 8 will take under the action of the inertia effect the active position shown in Fig. 4: and the levers Z Will, also owing to the inertia effect, remain in their lodging flush with the body I) of the fuse during the whole linear acceleration which exercises a much more powerful action on said levers Z than the angular inertia moment, derived from the rotary movement of the projectile. In other words: since the inertia effect in the direction of the translation is much greater than the angular inertia moment, the levers Z conserve their position according to Fig. f during the entire duration of the passage f the projectilethrough the spiral of the aannon.

As soon as the projectile leaves the mouth the of the cannon and therefore the linear acceleration has reached its end, the centrifugal power causes regardless of the resistance of the air, the spreading apart of the lovers Z which will take the slant position sion so that it will be'ready to function at l the moment of impact irrespective of the nature of the obstacle metwith and no matter what is the position in which the projectile arrives at the butt.

The fuse having thus been put under tension nothing will hinderany longer the axial I advance displacement of the sleeve 9 and this displacement will take place at the end of the trajectory in one of the following man ners:

1. Under the action of the inertia effect, which tends to throw the sleeve g forward if the projectile by its point strikes a relatively hard obstacle.

2. Under the action of the folding of the levers Z transmitted through the fingers d, in the case that the levers themselves are the first to meet the said obstacle, regardless of the fact if the latter offers but alittle resistance as for instance would be the case if striking barbed wire or the like.

3. Under the simultaneous effect of both of these mentioned actions if the obstacle met with is a liquid mass, or very soft ground, as marsh or the like, in which the projectile would easily enter if its bursting were not operated nearly upon grazing the ground owing to the conjunction of the inertiaeffect acting on the mass of the sleeve 9 and the foPding of the levers which in their .spread position offer to the obstacle a contact area which is great enough for securing the 1 small shanks of the two liberating fingers d to be operated by the two shanks of the relatively very long levers which they constitute.

4:. Under the simultaneous action of the inertia effect operating on the levers in the direction of folding a-nd the rebounding effect which tends to throw the sleeve 9 forward when upon arrival at the butt the projectile falls on its head.

I claim as my invention:

1. Percussion fuse for artillery projectiles submitted to a rotary movement around their axes during their trajectory comprising a control member submitted to the action of the centrifugal power in such a manner as to be adapted to become laterally standing out from the body of the fuse and to remain in this standing out position during the whole trajectory, regardless of the action of the resistance of the air, an oscillating memher for locking the striker constituting a lever adapted to swing in a plane perpendicular to the axis of the fuse and which is provided with a pin operating in the bore of a locking sleeve mounted to be axially movable in the direction of the advance of the projectile and concentric with regard to the striker, said sleeve being held in its active position against the action of a percussion spring during the whole trajectory of the. projectile by a device controlled by the displacement of said control member standing out from the body of the fuse during the trajectory of the projectile.

2. Percussion fuse according to claim 1, in which a centrifugal safety member is mountcd in a radial slit for immobilizing the said locking sleeve in its active position until the moment in which the projectile leaves the mouth of the cannon, said safety member being adapted to emerge under the action of the centrifugal power through the said radial slit.

3. Percussion fuse according to claim 1, in which a centrifugal safety member is mounted in a radial slit for immobilizing a locking sleeve in its active position until the moment in which the projectile leaves the mouth of the cannon, and in which the control member stands out from the body of the fuse during the trajectory of the projectile and is adapted to hold the said centrifugal safety member in its active position durin the passing of the projectile through the spires of the cannon.

1. Percussion fuse according to claim 1, in I Which the control member standing out from the body of the fuse during the trajectory of the projectile is constituted by a lever, a finger being provided which is adapted to become operated by the folding of said lever at the end of the trajectory When it meets an obstacle, in such a manner that a locking sleeve is sufiiciently axially displaced as to allow the liberation of a swiv'elling member locking the striker, a spring being arranged between said finger and the lever in order that upon the projectile leaving the mouth of the cannon, the spreading out of the lever causes the device for putting it under ten sion to be operative.

In testimony whereof I aflix my signature. 7

ANDRE VARAUD.

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