US2825284A

US2825284A - Impact fuzes with mechanical retardation

Info

Publication number: US2825284A
Application number: US532929A
Authority: US
Inventors: Kuhn Georges
Original assignee: Mefina SA
Current assignee: Mefina SA
Priority date: 1954-11-05
Filing date: 1955-09-07
Publication date: 1958-03-04
Anticipated expiration: 1975-03-04
Also published as: CH318216A; BE539348A; GB772918A; FR1126738A

Description

March 4, 1958 G. KUHN 2,825,284

IMPACT FUZES WITH MECHANICAL RETARDATION Filed Sept. 7, 1955 2 Sheets-Sheet 1 H C r f "a 5b k 7 18b INVENTOR Georges Kulzrc.

ATTO ENE Y IMPACT FUZES WITH MECHANICAL RETARDATION Georges Kuhn, Geneva, Switzerland, assignor to Mefina S. A., Fribourg, Switzerland, a corporation of Switzerland Application September 7, 1955, Serial No. 532,029

Claims priority, application Switzerland November 5, 1954 1 Claim. (Cl. 102-71) nited States Patent-"O Patented Mar. 4, 1958 walls 11a secured to the body C and acting on an axially movable body 10, against the action of a spring 12. In the normal position, said device is secured in the known manner by centrifugal locking members 9, located, for convenience of the drawing, in the plane of the section of Fig. 1.

The upper end of the rod 8 is located in the path of I the rod of the pusher 13 located in the head of the body z i the striker 5.

Said fuzes are not very sensitive and have no C, in the known manner, and adapted to be moved towards the interior of the said body on impact.

The other end of the rod 8 comprises a stop 8b which in the normal position is located opposite the bolt 7 of The operation of said fuze is as follows:

During. the firing of the shot, and when the axial acceleration ceases, the auto-destruction device, formed by the balls 11, the inclined surfaces 11a and the body 10, produces, under the action of centrifugal force, the compression of the spring 12 of the rod 8 and, at the same time, the locking "members of said rod move radially and release the shoulder 8a.

From this moment, the fuze can operate, either on impact, 'or by reason of the operation of the autotype of. fuze the retardation on impact is obtained by pyro-technical means which, however, are difiicult to store and operate in a very irregular manner, causing much longer periods of retardation or do not even provide it at all. i

The present invention has for its subject a sensitive fuze operating on impact with a mechanical delay and of which the striker is subjected to the action of a spring.

It is characterised in that its striker is held in the cocked position by a bolt, itself held in the locked position by a movable member controlled at least by a member actuated on impact.

One form of construction of the subject of the invention is shown diagrammatically and by way of example in the accompanying drawings, wherein:

Fig. 1 is an axial section.

Figs. 2 and 3 are cross-sections to a larger scale on the line IIII of Fig. 1 in the normal position and in the cocked position.

The fuze has a body C in which is located the main charge 1 of the detonator, with a relay 2 adapted to transmit to said charge the action of the combined percussion cap 3. The latter is mounted on an oscillating member 4 pivoted eccentrically at 4a. Said member comprises a toothed sector 4b gearing with a pinion 40 forming part of the rocker release mechanism 4d. This assembly forms a safety device for the detonator, as in the normal position, the percussion cap 3 is withdrawn from the path of the striker 5 and from the relay 2. It can only be moved opposite these members, after firing the projectile, under the action of centrifugal force.

The striker 5 is formed by a sliding rod subjected to the action of a spring 6, which at one end bears against a shoulder 5c of the body of the fuze and, on the other end, against a shoulder 5a of the rod 5, provided with a conical surface 5b. The striker is located eccentrically in the body C and parallel to the axis of the latter.

The conical part 5b of the striker is in contact with a bolt 7, with a rounded end 7a, and which slides in a radial bore located in a plane perpendicular to the axis of the body C.

Along the axis of the body C is located a sliding rod 8,

which is provided with a shoulder 8a subjected to the destruction device provided the safety device of the detonator has reached its active position.

In the first case, when the point of the fuze contacts an object, the pusher 13 is pushed towards the interior and its rod comes into contact with the upper end of the rod 8, which is thus moved axially.

This axial movement of the rod 8 moves the stop 86 so that the bolt 7 is released. The spring 6 acting on the striker then repels, by the conical part 5b in contact with the rounded part 7a the bolt 7 inwardly, and the striker is moved axially in the direction of the relay 2.

When the safety device of the detonator, formed by the oscillating member 4 carrying the percussion cap 3, which is set in operation, on firing the shot, in the known manner, has had time to function and the percussion cap 3 is opposite the striker, position shown in Fig. 3, the per- ,cussion cap is contacted and fires the charge 1 by means of the relay 2.

When the striker is released before the sector 4 has reached the position shown'in Fig. 3, it contacts a solid part of said sector. The projectile cannot explode.

If the projectile on which the foregoing described fuze is mounted does not strike the desired target, here an airplane, the explosion must be caused by the auto-destruction means including the axially movable body 10, the balls 11, and the spring 12 operating in the following manner:

When the gyratory movement of the projectile diminishes, the centrifugal force acting on the balls 11 also diminishes thereby causing the spring 12 to push the axially movable body 10 towards the main charge 1. The axially movable body 10 then contacts the shoulder 81: of the slidable rod 8 thereby causing the rod 8 to slide downwardly. Thestop 8a is thus displaced downwardly thereby freeing the bolt 7 thereby allowing the spring 6 to cause the downward movement of the striker 5. The striker 5 then penetrates the percussion cap 3, which has been brought into the path of striker S by the oscillating member 4, thus causing the destruction of the projectile before it falls to the ground.

It will be understood that'modifications may be made in the details of construction without departing from the scope of the invention. Thus the fuze need not comprise an auto-destruction device, or the safety device for the detonator and for the trajectory for maintaining percussion cap 3 out of reach of the striker 5, until the end of the safety path of travel of the trajectory.

The pusher 13 may form part of the rod 8.

Variations in the. retardation of the; release ofthe striker may be obtained by selection of the strength of its spring 6, the conicity of its part 5b and the size of its bolt 7.

I claim:

A sensitive fuze for a projectile having a projectile charge, comprising, in combination, a fuze body having an axis, a pusher member positioned in said body at its head portion and along said axis, an axially slidable ramming rod positioned in said body oppositely to said pusher rod at its upper end and alongsaid axis of said fuze body, said ramming rod having a shoulder portion intermediate its ends and a stop member at its lower end, centrifugal locking members positioned about said ramming rod about the portion thereof intermediate said shoulder portion and said stop member, said locking members abutting said shoulder portion of said ramming rod, an axially movable body positioned about said ramming rod at the portion thereof having said shoulder portion, first spring means positioned about said ramming rod for holding said axially movable body in position, ball means for causing said axially movable body to move downwardly against said spring means, a striker rod having a striking end, said striker rod being positioned in said fuze body and being parallel and eccentrically mounted with respect to said slidably mounted ramming rod, said striker rod having a conical surfaced shoulder portion intermediate its ends, one of said ends being a striking end, a projectile charge positioned in said body at its lower portion opposite to its head portion, a member mounted for oscillation on a plane perpendicular to the plane of the axis of said body, said member being eccentrically mounted with respect to the axis of said fuze body and to said striker rod and being positioned between the striking end of the striker rod and the projectile charge, a percussion cap mounted on said memher mounted for oscillation, second spring means positioned about said striker rod intermediate said conical surfaced shoulder portion and the end of said striker rod opposite to the striking end for urging said striker rod towards said projectile charge, said fuze body having a radial bore therein and positioned beneath said centrifugal locking members on a plane perpendicular to the plane of said axis of said fuze body, a bolt positioned in said bore, said bolt being in contact both with said stop member of said ramming rod and with said conical surfaced shoulder portion of said striker rod, whereby the fuze will be mechanically retarded in its functioning on impact with a target offering small resistance and whereby, upon the failure of the projectile to hit the target and upon the diminishing of the gyratory movement of the projectile with the accompanying diminishing of the centrifugal force acting on said ball means, said first spring means is caused to urge said axially movable body towards the projectile charge and said axially movable body contacts said shoulder portion of said ramming rod thereby causing said ramming rod to move towards said projectile charge and thereby causing said stop member of said ramming rod to be displaced downwardly to allow said second spring means to urge said conical surfaced shoulder portion to move said bolt radially and to urge said striker rod downwardly towards said projectile charge to cause the detonation of said charge before the projectile reaches the ground.

References Cited in the file of this patent UNITED STATES PATENTS 1,523,073 Junghans Jan. 31, 1925 2,149,469 Schenk Mar. 7, 1939 2,701,527 Granath Feb. 8, 1955 2,718,850 Kuhn Sept. 27, 1955