US1861521A - Fuse for rotating projectiles - Google Patents

Description

June 7, 1932. E. w. BRANDT 1,851,521

FUSE FOR ROTATING PROJECTILES Filed May 22. 1951 2 Sheets-Sheet l Y n il June 7, 1932. E. w. BRANDT FUSE FOR ROTATING PROJECTILES 2 Sheets-Sheet 2 Filed May 22. 1951 Patented .lune 7, 1232 EDGAR WILLIAM BRANDT, F PARIS, FRANCE FUSE FOR BOTATING PROJECTILES Application led May 22, 1931, Serial No. 539,382, and in France J'une 4, 1980.

The present invention has for an object a fuse intended to be mounted on rotating projectiles, and is capable of being utilized in anti-aircraft fire.

For such employment it is desirable that the fuse should be so constructed that:

1. It avoids any risk of accidental percussion during the'course of transport and handling.

2. It must not operate prematurely in case of encountering an unexpected obstacle in the gun barrel or upon leaving the mouth of the barrel.

3. It must subsequently be sensitized and capable of being actuated by an obstacle of very low mass (air-ship fabric).

4. It must be automatically re-locked dur-i ing the latter part of its trajectory, to avoid any danger of explosion `when the projectile falls back to the ground without having encountered its objective.

In order to respond to these conditions, employmentlias been made of the rotation at variable velocity to which the projectile is subjected during its trajectory when it is fired from a rifled barrel.

This velocity decreases little by little due to the effect of air resistance, and particularly in the case of projectiles of small diameter, the velocity of rotation may drop to a third or a quarter of its initial value. This peculiaritylias been applied, according to the present invention, in the followingr manner:

The fuse'comprises a safety device which opposes percussion duringl transport and manipulation. This device is moved out of the way at the end of a regulatable period of time after the firing of the shot, under the effect of centrifugal force. and comes into play` again, to prevent percussion, when the velocit)Y of rotation of the projectile falls below a certain value.

T he safety device is formed b v locking elements which are constantly held in active position by one or more elastic-elements Whose action can only be overcome temporarily by entrifugal force for a certain portion of the trajectory of the projectile.

'lhe invention has, further, a certain number of peculiar arrangements intended especially to maintain the firing pin in forward position in opposition tothe air resistance, to assure a uniform peripheral distribution of the locking elements during flight, to maintain the pyrotechnic elements firmly even 55, under the very high accelerations during propulsion, and, in a general manner, to attain a satisfactory and definite functioning.

Other advantages and peculiarities of the invention will appear from the following deec scription. K

On the accompanying drawings, solely by way of example:

Figure 1 is an axial section of a fuse according to the invention.

Figures 2 and-3 are diagrams of details. Figure 4 is an axial section of a modified form of construction.

Figure is a similar view of one particular construction of the firing pin.

Figure 6 is a transverse section on line 6 6 of Figure l, the balls being represented in dotted lines.

l Figures 7 to 11, inclusive, are axial sections of modified forms of construction of the fuse.

Figure 12 is a transverse section on line 12-12 of Figure 11.

Figures 13 and 14 are axial sections of other forms of construction.

Figure 15 is a transverse section on line 80 15--15 of Figure 14.

Figures 16 and 17 are axial sections of further modified forms of construction.

According to the form of .construction shown in Figure 1, the fuse comprises a firing pin 1 mounted to slide longitudinally in a strong nose piece 2, which is fastened to the body 3 of the projectile by intermediate pieces 4 and 5. This fastening is preferably produced by aid of the threaded portions 6 which 90 cooperate with the threaded portions 7 the threading being of suitable pitch and direction so that the effect of the rotation will tend to hold the pieces in position. The locking elements formed for example by the balls 8, are disposed in a cavity 9 around the firing pin l. These balls are actuated in such manner as to prevent the operation of the firing pin 1 when the fuse is not rotating.

For this purpose (Figure 1) they .are l0( centered in the locking'position by a ring 10 held by the yspring 11 which presses them onto a special seat 12 provided in the cavity 9.

. The form of this seat is chosen in such manner as to permit regulation of'the safety at themouth of the gun and to assure efficient locking at the end of the trajectory, as will be explained hereinafter. lThe said seat may comprise a groove 12a (Figure 2) having the form of the balls, or also a surface 12 (Figure 3) having a greater inclination with respect to the lower wall of the cavity 9, which as a whole may'advantageously have a diameter which increases from the rea;` toward the front (Figure 1).

y.The firing pin comprises a shoulder 13 of appropriate form for cooperating with the balls 8 to prevent any premature percussion. This shoulderl may have the same shape as the lower seat for the balls, or be form-ed differently, the assembly being preferably of suchtype as to imprison the balls 8 for more than a hemisphere in the locking position, as represented in Figures 2 and 3 where the normals to the points of external contact form between themselves angles, a, a', greater than 180 degrees.

The head of the iiring pin may comprise a proj eeting portion 14 which has the external shape of'the'projectile (Figure 1) or may remain rather Hat (Figure 4'). Its stem 1 '(Figure 5) has preferably, at one or more points, a section of lesser resistance than at the region of the supporting shoulder 13. This may be attained, for example, by aid of perforations (Figure 5), or again bygiving vthe firing pin, for a certain distance` a reduced cross section etc.

An abutment 17 (Figure 1), formed by Hanging or otherwise forming the piece,

j holds the firing pin 1 in its cavity, in opposition to the action of the spring 1I. which tends to move it toward the front. Other means vmay further be employed for holding the firmg pin in the position of Figure 1 during Hight. Thus, this may be attained by utilizing the reaction of the air` which may be caused to operate in known manner by count- 'er pressure upon the rear of the firing pin.

The channel 18 provided in the head of the firing pin and opening to the exterior at the point of maximum pressure (Figure 5) permits the establishment of this pressure atfthe interior of the fuse. A certain travel is provided between the point 19 of the'ring pin and the primer 20 which is held fast and supported by a ring or sleeve 21 solidly seated in the piece 5 by threading or otherwise (Figure 1).

With a Vvievi7 tol increasing the safety, the

' point of the firing pin and the sealing sheet 23 of the primer 20 may be formed in such manner as to constitute a soft point-hard plate of known type such as described in French Patent 1926.

Below the primer 20 is the detonator 24 whose bottom 25 may be fiat, but which has preferably an appropriateform, hemispherical for example, as at 25a (Figure 4), as'- suring the maximum of resistance of deformation under the effect of the forces to which the projectile is subjected, especially at lirmg. .l

Plastic washersl26 and 27, or Similar backings, maybe utilized to contribute inv assuring the immobility of the detonator and of the primer after they have been put in position. At firing, the positive acceleration forces the balls 8 solidly against their seat in the locking position under the effect of their own inertia as well as that of the ring pin 1. of the ring or sleeve 10 and of the spring 11. At the same time the assembly begins to rotate, carried along by the rotation of the projectile. The angle of inclination ofthe lower surface of the cavity 9 Figure 1) is "selected in such manner that the effect of centrifugal force, which tends to separate the balls 8 from the firing pin 1, remains less than the effect of the' forces of #622391, dated Febrry 9,

aoy

inertia. tending'to maintain the balls in the j' locking position during the entireduration of the positive acceleration.

When this'acceleration has ceased, the balls 8 separate from the firing pin, under the effect of the centrifugal force, pushing the ring or sleeve 10 forward, against the action of spring 11. However, this unlocking movement requires a certain time. In effect, the balls, supported against the walls of the cavity 9, are only carried along by the projeetlle progressively, and the unlocking can only take place when the balls have apquiredl a sufficient energy for raising the ring so that they may leave their seat and eventually free the outlet from the groove 12a (Figure 2).

'This time of retardation for the unlocking of the firing pin permits obtaining security at the mouth i. e. it avoids any premature percussion within the barrel and at passing from the mouth therefrom, when the projectile has not traversed a certain distance co rresponding to the time of retardation in question.

Furthermore, the duration or the distance of this safety may be regulated at will by varying the diameter of the portion of the cavity portion upon which the balls 8 roll. Tlius, by providing in the bottom wall of the cavity 9 a conical portion whose apex angle is less than that of the upper portion, the energy acquired at the beginning of the movement of the balls (for a given velocity) is diminished and the unlocking is thus retarded.

Thus the safety distance may also be regulated by varying the co-efficient of friction of the balls 8 on the walls of the cavity 9 which may for its purpose, be formed, covered, or

coated with various materials, for example, plastic materials, if it is desired to obtain a more rapid engagement of the balls for movement with the projectile, since the balls thus will tend to become encrusted in the- Ifiring is directed, its -velocity of rotationV gradually decreases under the .effect of the air resistance and the moment arises at which the energy, due to the rotation of the balls 8, will be insuiicientto overcome the pressure of the spring 11, which then automatically returns the ring or sleeve and the balls 8 into the locking position. From this moment percussion is no longer possible, and, at' the end of the trajectory, the projectile drops into the ground without exploding.

It may be remarked that the forms given to the supporting shoulder 13 of the firing pin and to the seat 12 or 12a for the balls 8 cooperate to firmly imprison the balls for more than Aa hemisphere (Figures 2 and 3) and thus oppose any effect of inertia capable of forcing the balls forward during the slowing down of the projectile in the ground.

This disposition is particularly interesting for cases where the projectile falls, at the end of its trajectory, onto a terrain of extremely low consistency, such as heath soil, a sandy shore, marshy ground. etc.

Itwill be understood that the angle of inclination of the walls of the cavity 9` the mass and the travel of the balls 8. as well as the force of the spring 11, are regulated in order that the unlocking and relocking may take place at. suitable points of the trajectory, account b eing taken of the velocity of rotation of the projectile.

Radial pathways for rolling may. if desired, be provided on the. lower surface of the ring or sleeve 10 (Figure 6), or inthe cavity .9, to assure a uniform peripheral distribution of the balls 8 on these walls.

In case ofan accidental fall from a great 2 height or an extremely violent shock, the liring pin 1 (Figure 5) will be deformed or crushed in adjacent the holes 16 without the pin 19 causing the firing ofthe primer 20.

Figure 7 shows that a ring or sleeve 32 may be utilized which is fiared out toward the bottom and whose internal walls play a part analogous to that of the conical walls of the cavity 9 of Figure 1.

In the construction of Figures 4 and 8. the assembly of the fuse is enclosed in a body *5 33 formed of a single piece, threaded at 34 into the projectile. The point 19 of the tiring pin 1 is disposed in such manner as to directly actuate the detonator 24 without the interposition of a primer. This detonator is preferably embedded in the charge as represented, t-o assure thc ignition under the best possible conditions. l't may loe formed by materials under different compressions or of different nature, chosen in such manner as to attain at thc same time the sensitivity and the safety of functioning,r which are desired. Thus. for example, the material (fulminate) placed in the upper portion of the detonator may be less rammed or of more sensitive composition than the material placed beneath. l

The shoulder 37 (Figure 4) constantly maintains the projectile charge near the detonator 24, even if under the action of the initial acceleration, a certain packing or ramming is produced in the cavity 38.

In the construction of Figure 8, the ring or sleeve 1,0 and the spring 11 of Figures 1 to 5, inclusivfef, are replaced by a rigid washer 39 and an elastic or plastic Washer 43 (of cork, for lexample) which plays the same parts as these two elements.

The elements for locking ,the firing pin may also be formed by balls 8 subjected to the action of springs 40 disposed in radial cavities 41 and coming into engagement. with the firing pin 1 (Figurel 9), or again by one or more Wedge pie es'f42 which may be inserted between the'iriiig pin and the primer 20 .(Figure 10) or by segments 45 (Figures 11 and 12). 45a. (Figure 13) which are extensible under the action of centrifugal force or in opposition to the action of a spring or other elastic element (Figure 12).

In another form of construction (Figures 14 and 15) the firing pin comprises elements 45, connected to or formed integral with it, which yield to the impact, when the balls have gained the unlocking position, to permit the. tiring pin to come into engagement with the primer 20. Thus a certain travel between the pin 19 and the primer 20 is gained at the moment of the percussion, which is essential for a correct function.

Figure 16 shows another construction according to which the ifiring pin 1 is seated, at rest, on the head of the fuse, 51. and comprises a hollow extension 52 enclosing the primer Under the effect of rotation, the balls 8 bring the firing pin into the position 1a (Figure 17) in opposition to the spring 11 and percussion takes place at impact by the crushing of the portion 52 and the projection of the primer 20 onto the firing pin which has been stopped by the objective. A

Figure 17 shows a construction analogous thereto with the sole difference that the firing pin 1n. is fastened on its extension 57 by a pin 58 which is broken at impact.

Figures l, 16 and 17 show that the fuse may have a form perfectly 'corresponding to or capable of construction 1n a very smal] space,

is particularly suited for projectile of small caliber.

rlhe principle of its operation also renders it especially valuable forthat type of projectiles in which the velocity of rotation, all other things being equal, decreases in large proportion during the course of the trajectory under the effect of air resistance".

lt will be understood that its application to projectiles of larger caliber is only a matter of regulation.

Naturally, 'the illustrated and described modes of construction have only been chosen by way of example; numerous modifications of detail may be employed without departing from the scope of the invention.

Having thus described the invention, what ll claim as new and desire to secure by Letters Patent, is

l. A fuse for rotative ing a body, onater, firing cated between said member and anvinternal surface of said body and operated by cenprojectiles comprisa contact firing member, a deta deformable ring surrounding said trifugal force to move radially away from said firing member, whereby they pass from a locking position into a position in which they will cause and permit deformation of said deformable member upon impact and permit said firing'member to engage "said detonator.

2. A fuse for rotative projectiles comprising a body of one piece havingf cavities at the front and rear ends thereof and'being adapted to be seated in the front end of the" projectile, said front cavity having a concave conical rearward surface, a contact firing member extending through said front cavity and having a shoulder adjacent said conical surface, a spring and a spring follower in said front cavity, said follower having an annular surface opposite said conical surface and being urged theretoward by said spring, a plurality of balls located around said firing memberand betweenthe surfaces, a detonator located in said rear cavity, the firing pin being adapted topass through an. opening between said'cavities and operating upon lmp-act to lire said detonator.

' 3. Fuse for rotative projectiles comprising a body, a primer, device for normally preventing contact of said primer and pin, a resilient element for holding said safety device in safety position,

i for moving said safety f'said resilient Velement said device including a means operated by centrifugal effect after the beginning of iiight device to permit firing,

operating upon said member, and a plurality of balls loa firing pin, and a safety` device when the speed of rotation has dropped to below a predetermined value to return said safety devlce into safety position, the saidl resilient element also serving for holding said firing pin and said primer apart after the ing contact between said firing'pin and primer during transport and movable under centrifugal force into a position for permitting such firing, a resilient element for holding said safety. device in safety position and formoving it from firing position to safety position when the centrifugal force has dropped below a predetermined value, --the said resilient element also serving to force the firing pin forward in opposition to the effect of air resistance after the safety device has been moved from safety position.

- 5. Fuse for rotative projectiles comprising a body, a primer, a firing pin, safety means including balls adapted to be moved outwardly by centrifugal force after the pro-v jectile has begun its flight, a resilient element for holding said balls in safety position and for returning said balls to safety position when the speed of rotationof the projectile has dropped below a predetermined' value, the said resilient element also serving for retaining the firing pin and primer apart when the safety device is in firing position.

6. A fuse for rotative .projectiles comprising a body, a primer,

ty device including balls for holding said pin from contact with said primer while in a normal safety position," means ,on said body for providing a conical into a firing position after the commencement of the flight of the projectile, and a resilient element for normally holding` said balls in safety position Vduring transport and for re-` turning them fiom firing position to safety position when the speed of rotation of the,

projectile has dropped to below a predetermined value, the said resilientelement also servlng for retaining the firing pin and the primer apart vwhile the balls are in firing seat, and resilient means Vbearing against said ring to hold said balls vin safety position and to return the balls fromfiring into safety pos1tion,said resilient means reacting against a firing pin, and a safe- Y seat for said-balls along` y which they are moved by centrifugal force saidA pin from said firing pinto hold it away from said primer.

8. Fuse for rotative projectiles comprising a body, a primer, a firing pin, a safety means including balls for holding said pin from Contact with said primer while in a normal safety position, means on said body for providing a conical seat for said balls, a ring for engaging said balls while on said seat, and a spring engaging' said ring for holding said balls in safety position on said seat and for moving the balls from firing to safety position, said spring at its'other end engaging said firing pin for holding it away from said primer.-

- 9. Fuse for rotative projectiles comprising a body, a primer, a firingpin, said firing pin including a conical shoulder, means o n said body for providing a conical seat having an apex angle less than the apex angle on said conical shoulder, balls located between said shoulder and said seat and actuated by centrifugal force during ili ht to move away from the axis of the pro]ectile and thereby force said shoulder away from said seat, and means for opposing said ,movement of the balls.

10. Fuse for rotative projectiles comprising a body, a primer element, a firing pin element, one of said elements being movable tot ward the other for detonatng the fuse, a safety device for'normally holding the movable element against detonating movement and actuated by centrifugal force during flight to move from its normal `safety position into ring position whereby to permit detonating movement of said movable element, a ring member, a flange member on said body, said members being engaged with the safety device and one of said members having an inclined surface whereby the movement of the safety device will cause said ring member to move axially, and resilient means engaged between said movable element and said ring member for holding said elements apart and for actuating said ring member for returning said safety device to safety position when the rotative speed of the body drops below a predetermined value.

11. A fuse as in claim 10, in which the safety device comprises a plurality of balls, and said one member has a plurality of similar surfaces for said balls, one of said members also being provided with grooves spaced at equiangular distances about the fuse axis so that the walls of the grooves ywill assure a uniform peripheral distribution of the said balls. i,

12. Fuse for rotative rojectiles comprisa body, a primer, a ring pin, a primer holder for said primer, a connection between prising a seat on said body for the firing pin and means for raising said firing pin and primer holder from their position of rest, said means being actuated by centrifugal force. y

13. Fuse for rotative projectiles comprising a body, a primer mounted in said body, a ring pin movable in said body, a resilient element adapted to force said firing pin forwardly in said body away from said primer, a ring surrounding said firing pin and engaged by the other end of said spring so that it is forced rearwardly thereby, ballslocated between said ring and a conical seat on ysaid body and movable between an inward safety osition in which they prevent movement of said firing pin and an outward firing position in which they permit the detonating movement of said firing pin, said ring and seat being constructed and arranged to oppose the outward movement of said balls, said balls in their outward movement by centrifugal force upon tiring operating to move said ring forward against said resilient element so that said resilient element will cause said ring to return said balls from firing to safety position when the centrifugal force has dropped below a predetermined value.

In testimony whereof, I aiiix my signature.

EDGAR WILLIAM BRANDT.

said firing pin and the primer holder for e normally maintainingthe firing pin away from said primer, said connection yielding l55 under the shock of impact, safety means com-

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