US2236495A - Percussion fuse - Google Patents

Description

March 25, 1941. M. BlRKlG-r YERCUSSION FUSE Filed oct. 21, 195s a W, n W W Patented Mar. 25, 1941 ,UNiTEo STATES Application October '21, 1938, Serial No. 236,366 In Belgium January 21, 1938 (Cl. lim-39) ence to the accompanying drawing, given merely by way of example, and in which:

Fig. 1 is an axial sectional View of a percussion fuse made according to an embodiment of the invention;

Fig. 2 is a sectional view, corresponding to the same embodiment, but showing the parts in different respective positions.

In the following description, it will be assumed that the invention is applied to the production of a percussion fuse of the type above mentioned, for a shell of small caliber to be used in a firearm provided with rif'ling.

The general structure of the fuse, excepting the percussion means thereof, can be made of any suitable conventional manner, for instance as illustrated by the drawing.

In this embodiment, the fuse includes a body 9 Claims.

The present invention relates to percussion fuses for projectiles rotating about their axes,

of the type in which the percussion system is.

` y temporarily locked in inoperative position by one or several pins adapted to be moved out of lockingposition, so as to release the percussion system, under the effect of the centrifugal acceleration resulting from the rotation of the projectile -about its axis. The invention is more especially, although not exclusively, concerned with percussion fuses of this type for shells of small calibre.

In fuses of this type existing prior tov my invention, the locking pins above referred to were 1 driven off from the fuse body when the percussion system was released.

Now, the pins thus driven off from the body Were moving at a very high speed, which involved very serious drawbacks, especially when the projectiles were utilized in firearms tted on aircraft, since, in this case, said pins could damage certain vital parts of said aircraft.

The chief object of -the present invention is to provide a fuse of the type above referred to which is better adapted to meet the requirements of practice and in particular which avoids the serious drawback above mentioned.

According to an essential feature of the present invention, the percussion fuse includes at least one pin adapted temporarily to lock the percussion system in inactive position, said pin lbeing adapted to be moved out of locking position by the centrifugal acceleration resulting 3 from the rotation of the projectile around its axis, and a recess is provided for receiving said pin, at the time of the release of the percussion system, so that it cannot be driven out of the fuse.

40 According to another feature of the present invention, the pin in question serves to lock a striker which, together with said pin, is carried by a movable support temporarily maintained in a position of rest for which said pin and its recess or housing are not located in register with each other, said support being adapted to occupy,

' under the influence of certain variations of the acceleration of the projectile along its trajectory, an active position for which said pin and said recess or housing are located opposite each other.

Other features of the present invention will result from the following detailed description of some specific embodiments thereof.

Preferred embodiments of the present invention will be hereinafter described, with referl on which is secured, by screwing, a cap 2, saidv ECE body being adapted to fit into the mouth of the shell. through'the medium of a threaded ring 3. 'Ihis body l carries a sheath 4 inwhich a detonator is housed, said sheath being secured by screwing to the base of ring 3.

A primercarrier 6 is provided with a flange caught between the fuse body I and said sheath 4.

The front part of the fuse is closed by means of a thin sheet or disc 1, which is, for instance, caught, along its periphery, between the body I and the cap 2 of the fuse.

I will now describe the percussion system which constitutes the object of the invention.

Advantageously, lthis percussion system includes, in the known manner, a striker 8, normally kept in inactive position by pins 9 or equivalent means (two such pins being used in the embodiment shown by the drawing) adapted to be moved away radially, so as to release said striker, under the effect of the centrifugal acceleration resulting from the rotation of the pro- J'ectile about its axis.

According to the chief feature of the present invention, the device is arranged in such manner that pins 9 can be driven off .into recesses `Il) capable of preventing them from being expelled from the body of the fuse.

Such an arrangement therefore obviates any risk of accidents such as those inherent in -the operation of fuses having locking pins which are expelled from the fuse body.

l Preferably, according to a further feature of the present invention, these recesses are wholly closed at their end farthest from the axis of the fuse.

each of these recesses may be formed partly in the body I of the fuse and partly in its cap 2, by providing in these two last mentioned elements two radial holes, respectively, which open into an axial hole II forming a housing for striker 8. Each of these radial recesses has a bottom I 0 against which the corresponding locking pin 9 is applied when the striker is released.

With such an arrangement, I prevent the possibility of destructive agents leaking in into the body of the fuse, and in particular the possibility of an inflow of water, which might damage the primer of said fuse.

A fuse as above described further includes means for opposing premature release of striker 8, that is to say for preventing the'fuse from acting at too short a distance fromA the gunVV v port I2 is adapted to occupy, under the effect of certain variations of the acceleration of the projectile along its trajectory, an active position for which these pins are located opposite their respective recesses, so that they can now be moved r away radially under the effect of the centrifugal acceleration and release the striker.

Such an operation may, for instance, advantageously be obtained with the specific arrangement shown by the drawing.

In this embodiment, in order temporarily to maintain support I2 in its position `of rest, I provide a locking means capable of releasing said support under the effect of the centrifugal acceleration. This locking means consists, for iny stance, of a split segment I3, interposed between the body I of the fuse and a shoulder I2 provided at the base of the sliding support I2.

The outer ends of pins 9 are made of frustoconical shape so that they can already be partly engaged in recesses Ill when support I2 is in position of rest.

The forces acting upon support I2 after a shot has been red, are then the following:

On the one hand, an axial force resulting from the inertia of said support. The direction of this force changes at the same time as that of the acceleration of the projectile along its trajectory, that is to say after the projectile has left the firearm; and,

On the other hand, another axial force, directed toward the front end of the fuse, resulting from the reaction of the edges of recesses I0 upon the frusto-conical ends of pins 9, which are urged lin the radial outward direction by the centrifugal acceleration.

It will readily be understood that it is vpossible, by suitably choosing the weights of support I2 and pins 9, and also the angle of theY cone of the latter, to obtain the result that the resultant of these forces is directed toward the front end of the fuse, that is to say causes support I2 to pass from its position of rest to its active position, only after the projectile has moved to a given distance from the muzzle of the firearm. This distance, added to that corresponding tothe axial change of position of support I2, determines the margin of safety.

In particular, in the case of shells of small calibre, it is particularly advantageous to determine the weights above referred to in such manner that this distance is equal to some meters.

rI'he fuse above described will operate in the following manner:

In position of rest, that is to say before the projectile is introduced into the firearm, the various elements of the percussion system respectively occupy the positions of Fig. 1, support I2 being held in position of rest by segment I3.

When the shot is red, the projectile starts rotating about its axis and said segment is moved away by the centrifugal force, thus releasing support I2, which however remains for a short time in position of rest due to the fact that the acceleration of the projectile along its trajectory has an important positive value. When this value drops below a certain value lower than that acting at the gun muzzle, said support comes into its active position and pins 9 are engaged into theirrecesses (position shown by Fig. 2). The fuse is now ready to operate. When the projectile strikes an obstacle, cover disc 'I is broken andstriker 8 driven in. The point of this striker now strikes the fuse primer, so that said fuse now detonates.

Whatever be the embodiment that is chosen, the fuse according to the present invention has, in addition to the advantages above set forth, that of being of a simple construction, so that its cost of manufacture is relatively low and its operation is reliable.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efcient embodiments of the present invention, it should be well understood that I do noty wish to be limited thereto as there might be changes made in the arrangement, disposition, and form of the parts without departing from the principle of the present invention as comprehended within the scope of the appended claims.

What I claim is:

1. A percussion fuse of the type described which comprises, in combination, a frame, a support movable axially in said frame between two extreme positions, a percussion device carried f support in an inoperative position, said locking member being movable radially away from the axis of the fuse by centrifugal force to release said percussion device, at least one hole in said frame, said hole being so located that said locking member is in register with said hole only when said support reaches its extreme position nearest the front of the fuse, and locking means for temporarily locking said support in its other extreme position, said last means being brought out of action by centrifugal force only, whereby said support can move towards the front of the fuse only after the shot is fired.

2. A percussion fuse of the type described which comprises, in combination, a frame, a support movable axially in said frame between two extreme positions, a striker carried by said support and movable axially with respect thereto, at least one locking pin mounted in said support normally locking said striker against movement with respect to said support in an inoperative position, said locking pin being movable radially away from the axis of the fuse by centrifugal force to release said striker, at least one hole in said frame, said hole being so located that said locking pin is in register with said hole only when sai-d support reaches its extreme position nearest the front of the fuse, and locking means for temporarily locking said support in its other extreme position, said last means being brought out of action by centrifugal force only, whereby said support can be moved towards the front of the fuse only after the shot is fired,

3. A percussion fuse of the type described which comprises, in combination, a frame, a support movable axially in said frame between two extreme positions, a percussion device carried by said support and movable axially with respect thereto, at least one locking member mounted in said support normally locking said percussion device against movement with respect to said support in an inoperative position, said locking member being movable radially away from the axis of the fuse by centrifugal force to release said percussion device, at least one hole in said frame, said hole being so located that said locking member is in register with said hole only when said support reaches its extreme position nearest the front of the fuse, at least one abutment carried by said frame, at least one inclined surface on said locking member, said abutment and inclined surface cooperating to produce by the centrifugal force acting on said locking member a reaction parallel to the axis of the fuse tending to move said support towards its extreme position nearest the front of the fuse, and locking means for temporarily locking said support in its other extreme position, said means being brought out of action by centrifugal force only, whereby said support can be moved towards the front of the fuse only after the shot is red.

4. A percussion fuse of the type described which comprises, in combination, a frame, a support movable axially in said frame between two extreme positions, a striker carried by said support and movable axially with respect thereto, at least one locking pin mounted in said support normally locking said striker against movement with respect to said support in an inoperative position, said locking member being movable radially away from the axis of the fuse by centrifugal force to release said striker, at least one hole in said frame, said hole being so located that said locking pin is in register with said hole only when said support reaches its extreme position nearest the front of the fuse, at least one inclined surface on said locking pin, at least one abutment carried by said frame, said abutment and inclined surface cooperating to produce by the centrifugal force acting on said locking pin a reaction parallel to the axis of the fuse tending to move said support towards its extreme position nearest the front of the fuse,and locking means for temporarily locking said support in its other extreme position, said means being brought out of action by centrifugal force only, whereby said support can be moved towards the front of the fuse only after the shot is fired.

5. A percussion fuse according to claim 2 in which the outer end of said pin is of frusto-conical shape, and said locking means normally lock said support in such an axial position that said frusto-conical end is engaged at an intermediate point along its conical surface with the edge of said hole, whereby the centrifugal force acting upon said pin after the fuse has started rotating about its axis tends by reaction on the edge of said hole of said frusto-conical end to urge said support towards the front of the fuse.

6. A percussion fuse according to claim 1 in which the locking means of the support comprise a split segment interposed between said support and said frame and capable of being forced open by centrifugal force.

7. A percussion fuse according to claim 2 in which the locking means of the support comprise o a split segment interposed between said support and said frame and capable of being forced open by centrifugal force.

8. A percussion fuse according to claim 2 in which the locking means of the support comprise a split segment interposed between said support and said frame and capable of being forced open by centrifugal force and in which the outer end of said pin is of frusto-conical shape, and said locking means normally lock said support in such Y an axial position that said frusto-conical end is engaged at an intermediate point along its conical surface with the edge of said hole, whereby the centrifugal force acting upon said pin after the fuse has started rotating about its axis tends by reaction on the edge of said hole of said frustoconical end to urge said support towards the front of the fuse.

9. In a percussion fuse according to claim 1, sai-d frame having a recess therein, said support having a flange thereon within said recess, and said locking means comprising a split elastic ring normallypositioned between said flange and the bottom of said recess.

MARC BIRKIGT.

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