US2900873A - Ordnance - Google Patents

Description

H. WUST ORDNANCE Aug. 25,, 1959 2 Sheets-Sheet 1 Filed Oct. 30, 1956 H. WUST ORDNANCE Aug. 25, 1959 2 Sheets-Sheet 2 Filed 001;. 30, 1956 2,900,873 Patented Aug. 25, 1959 ORDNANCE Hans Wiist, Vichy, France, assignor to Manufacture de Machines du Haut-Rhin, Mulhouse-Bourtzwiller, France Application October 30, 1956, Serial No. 619,327

Claims priority, application France November 10, 1955 6 Claims. (Cl. 89-1) It is a well known fact that the desired accuracy for the point of impact of elongated missiles projected out of the inner tubes of a piece of ordnance may be obtained by stabilizing said missiles on their path through the provision on the inner wall of the inner tubes of a rifling constituted by twisted grooves which impart to the missile fired by the gun a rotary movement round its longitudinal axis through engagement of said grooves with the driving bands on the missile.

Generally, the effect of a missile is by no means jeopardized by such a rotation; however there is one case at least in which such a rotation of the missile is objectionable; this case is that of missiles containing a hollow or shaped charge.

Missiles with shaped charges are used to a wide extent nowadays by reason of their considerable disruptive effect, chiefly in the case of action against armoured cars. The power of penetration of a shaped charge is at a maximum when the missile does not revolve round its axis and it is all the more reduced when the missile revolves at a higher rate. For a shaped charge shell of a conventional type and of a mean size for instance, the power of penetration begins decreasing substantially already for a speed of revolution of about 1,000 rpm. and for 15,000 rpm, it may sink down to 50 or 40% of its peak value. To cut out this drawback, missiles with shaped charges have been frequently used as rockets, but the accuracy is then considerably decreased. In contradistinction, when firing with rifled pieces of ordnance, it is possible to obtain a higher accuracy, but this is reached I at the expense of the power of penetration of the shell.

It has been already endeavoured to obtain both an improved accuracy in firing and a high power of penetration by resorting to missiles constituted by two sections adapted to rotate with reference to each other, the outer section assuming a speed of rotation sufficient for stabilizing the missile as a whole while the inner section containing the shaped charge does not rotate or rotates only at a very low rate until the missile impinges against the target. In order to reduce the friction to an amount as small as possible with a view to preventing or at least reducing the transmission of the rotary movement of the outer section to the inner section of the shell, it has been proposed to use for instance roller bearings or the like between said sections. Such roller bearings should be sufiiciently sturdy so that they may resist the shocks to which they are subjected at the moment of the firing. For instance, assuming that the inner section of the missile weighs 2.5 kg. and that the acceleration at the start is equal at the maximum to 20,000 g, (g or acceleration of gravity being equal to 9.81 meters per second), the stress to be transmitted by the roller bearings to the inner section of the shell is of the magnitude of about 50 tons.

The present invention brings a remedy to this prior condition through the agency of an inner ordnance tube provided, in addition to its normal twisted grooves with one or more supplemental grooves extending in parallelism with the axis of the tube or having a slight twist in a direction opposed to that of the twist of the conventional grooves, said inner ordnance tube being associated with a corresponding missile including two sections adapted to revolve with reference to each other While the inner section of the missile carries guiding members adapted to slide in the supplemental grooves so as to prevent the said inner section from being driven into rotation or to impart thereto a slight rotation in a direction opposed to that of the rotation of the outer section. These guiding means should be designed so as to be sufficiently resistant from a mechanical standpoint.

This novel arrangement provides substantial advantages. The transmission of the stress exerted at the moment of the firing between the outer and the inner section of the shell, which stress in the above example was of the order of about 50 tons becomes a very simple matter. In the most favorable case, it is sufiicient to provide mere smooth surfaces between the two sections since the guiding members produce a torque sufiicient for absorbing even the stresses arising through a sliding frictional engagement.

The speed of rotation of the inner section of the missile when it is urged out of the muzzle is exactly defined and it is for instance equal to zero or to any other selected value. For instance, in the case of an anti-tank gun and for a fighting distance of about 1,200 meters, the conventional grooves being twisted by 8 to the right, the supplemental grooves should be slightly twisted towards the left so that the rotation towards the left hand side assumed by the inner section of the missile when the latter is passing out of the muzzle may be reduced to zero at a distance of about 600 meters and be transformed at a distance of 1,200 meters into a slight right-handed rotation.

When the missile has left the inner tube, it is possible to make the inner section of the missile slide to a small extent, say by a few tenths of a millimeter forwardly with reference to the outer section, for instance through the agency of a spring, the power of which may be slightly above the resistance opposed by the atmospheric air. This provides for a separation between the surfaces serving for the transmission of the stresses at the moment of the firing while the friction between the inner and the outer sections is thus reduced. To provide for the relative rotation between the two sections after the missile has left the inner tube, it is sufiicient to resort to small and light roller bearings and even in certain cases to mere slideways.

The guiding members are preferably fitted over the cap of the missile. They may assume the shape of blades and in this case they may constitute fins, the angle of lead of which is selected so as to absorb at least approximately the rotary torque produced by friction and consequently to oppose any transmission of the rotary movement between the outer and the inner section of the missile. Obviously, it is also possible to separate the guiding and the torque-absorbing parts and to provide, independently of the guiding members constituted for instance by sliding bars, separate fins on the cap of the missile.

There is an application of the above fundamental principle which is obvious for anyone skilled in the art, to wit the anti-tank guns firing missiles carrying a shaped charge and stabilized bygrooves in the inner gun tube. A preferred amendment of the present ihven'tioii' will now be described by way of example, reference being made to Figs. 1 and 2 of the accompanying drawings, wherein:

Fig. l is an axial cross-section of the improved missile. Fig. 2 is a diagrammatic developed showing of a part of the inner surface'of the inner tube firing such amissile. The'm'issile' includes an" inner sleeve 1' enclosingthe shaped charge 2 with its'cover 3. Over the end of the sleeve 1 is fitted the conical point or cap 4' of the missile, said cap carrying a number of blades or fins 5 the outer edges of which are'pa'r'allel with the axis of the missile and are'located' on' a cylindrical surface the diameter of which is slightly larger than the gun calibre. To the front, the cap 4' carries an electrically igni'table fuse' 6' connected on the onehand through the" mass constituted by thecap 4' of the missile; the sleeve ll,- etc. and on the other hand through the insulated wire 7 with-the igniting system 8' which controls the relay 9 so as to produce the defiag'ration of the explosive charge 2. Instead of an electric fuse, it is also possible touse' a fuse of any other type such as a percussion fuse either at the tip of the missile cap or at the rear, inside the bottom of the shell to' act as an' inertia fuse, etc. v

The inner sleeve 1 is revolubly mounted inside an outer sleeve or sheath 11 with the interposition of the'needle bearing 12; The outer sleeve or sheath 11' is provided with at least one driving band 13. Generally speaking,

there are provided at suitable distancesfrom the: actual drivingband 13 one or' more auxiliary bands 14 the part played by which will be" disclosed hereinafter. The bot tom 15 of the sheath 11 contains other arrangements suchas'the spring 16 the force exerted by which is' higher than" the resistance opposed by the air and which-urgessligh'tlyforward the-inner sleeve 1 through the agency of the piston 17 when the missile has passed" out ofthe muzzle-of the piece of ordnance;

In the bottom of the inner sleeve 1 may behoused further arrangements,- such as a safety system for the ignition'means', etc. Obviously, the missile may in the conventional manner form part of a cartridge through engagement in a case containing the propelling charge.

The inner tube 2 of the piece of ordnance illustrated in Fig. 2 shows on the one hand the normal inner structure of a conventional gun with the twisted grooves 18 and thepartitions or lands 19 between the latter. These grooves extend along a spiral path forming a selected suitable angl e'with the axis of the gun so as to impart to the outer section 11 of the'missile the desired rotation through cooperation with the driving bands 13 and14l In addition to such conventional grooves, the inner tube isprovided according to the invention with a number of' supplemental grooves 20' which in the example selected are parallel with the axis of the tube, although they may be given a slight pitch'in' a directionopposedto'that' of the" pitch of the conventional grooves, said slight pitch being say of the order of about 1, while the pitch of the con-' ventional grooves is' generally equal to about'7 at least and in fact be substantially higher as will be disclosed hereinafter. These supplemental grooves the' number of which, say between 3' and 6, is equal to that of the blades or bars 5 on the periphery of the missile guide said blades or bars at the moment of the firing. The depth of these supplemental grooves 20 is preferably equal to that of the conventional grooves 18 or slightly smaller. The partitions or lands 19 are at different points intersected by said supplemental grooves ZG'and accordingly the supplemental grooves are formed from aligned discontinuities in the lands. However, in order to prevent any forward leaking of the propelling gases at the moment of-the firing, it is possible as already mentioned to provide'the'missile with further supplemental drivingbands-14 the spacing between which'is such that, at any moment at least one of them provides for fluidtightness.

Thus, for instance and as shown in Fig. 2, when the primary driviiig' band 13 enters a cross-sectional area in which the partitions are cut by the supplemental grooves, fluidtightness is ensured by the associated driving band 14 moving through an area in which the partitions are not cut by the supplemental grooves.

There exists a number of modifications and of furthe applications of the principle disclosed hereinabove and for instance, it is possible to execute the outer sleeve or sheath 11 of the missile with a greatly reduced thickness and with a lesser weight than the case illustrated in Fig. 1. Thus, weight is economized and it is also possibleto're's'oft to an outer sleeve'll which is substantially shortef thari tha t illustrated so that therorenagf heedle bearing may be shifted rearwardly and be located just ahead of-thforemost driving band 13. This shortening "ofthe outer sleeve shows. the advantage that it is thus possibleto give the nan of'the shaped charge 2 and of its cover 3 a larger diameter, said diameter defining the capacity of penetrationof the missile.

A missile being stabilized through the agency of conventional grooves, the inner sleeve 1 may be made'longer or the enter sleeve ll' lighter or' shorter and if his sired-however in such a case to retain or even-improve the'stahility'of them'issile duringits' flight together with a highaccuracy in-the firing," it is necessary to increase the speed of rotation of the outer sleeve 1 1',i.e. the angle- 6f twist of the conventionalgroovesi This increase is easy matter even up to 'values' above those generally c sidered hitherto as necessary andusual, for instance uir to angles of-lS and above.

A' further application of the principle underlying invention consists in making use of the relative to movement'ofthe inner sleeve section 1 of the missile W1 reference to the outer section 11 thereof for the actua tion' of any desired mechanism, for instance for releasing the" safety system associated with the' ig nition'means at af predetermined-point of the path of the missile, say at meters beyond the muzzle of the gun. This leads'to applications" which are of still further interest. It'is possibleto give'the'inner sleeve l any desiredlength'an'd to stabilize it through the agency of fins Which,'upon the missile passing out of the inner tube, are urged'outwardly in'a predetermined uniform manner. In this case, the outer rotary section should be very short and thechief partsplayed by the latter consist in this case in providing forfluidtightness, in protecting the stabilizing fins against theaction of thegases formed by the gunpowder and in 'con'trollingthe desired predetermined and uniforni expansionjof said stabilizing fins. v V

Theapplications of the invention defined in the aecofii panying claims include also the use of missiles having a coii siderable length and housing a multiplicity of shaped charges. V i

What I' claim is:

1. ordnance system a pns'ing a gun massin "tube provided with circumferentially spaced lands forming conventional spiral rifling grooves between them, the lands having di scontinuities aligned to tom-supplemental rifiingi' comprising at least one supplemental groove, said" supplemental groove forming with the longitudinal of the tube an angle the value of which is selected be; tween' zero so that the groove is substantially parallel to thejaxis and a small value thereby to form a spiral opposite to that of the conventional rifling grooves of said tube and having a depthno greater than the depth oft'ne length to maintain a portion thereof constantly engaging portions of the lands that are continuous and uninterrupted, and at least one guiding radial vane carried by the outer surface of the inner portion of the missile for slidably engaging the supplemental groove of the gun tube.

2. An ordnance system comprising a gun including a tube provided with circumferentially spaced lands forming conventional spiral rifling grooves between them, the lands having discontinuities aligned to form supplemental rifling comprising at least one supplemental groove, said supplemental groove forming with the longitudinal axis of the tube an angle the value of which is selected between zero so that the groove is substantially parallel to the axis and a small value thereby to form a spiral opposite to that of the conventional rifling grooves of said tube and having a depth no greater than *the depth of the conventional grooves, a missile to be fired from the gun including a first outer portion and an inner portion coaxial therewith for carrying a charge and revolubly carried inside the outer portion and extending outwardly at one end thereof, a plurality of driving bands on the outside periphery of the outer portion of the missile for engaging the conventional rifling grooves of the tube of the gun, the driving bands being disposed axially on said outer portion in a predetermined axial spacing so that at least one of the driving bands engages portions of the lands which are free of discontinuities when another band is moving through an area in which at least one land is discontinuous thereby to constantly maintain fluid-tightness between the missile and the tube when the gun is fired, and at least one guiding member carried by the outer surface of the inner portion of the missile and extending radially therefrom in a single plane for slidably engaging the supplemental groove in the tube.

3. An ordnance system comprising a gun including a tube provided with circumferentially spaced lands forming conventional spiral rifling grooves between them, the lands having discontinuities aligned to form supplemental rifling comprising at least one supplemental groove, said supplemental groove forming with the longitudinal axis of the tube an angle the value of which is selected between zero so that the groove is parallel to the axis and a small value thereby to form a spiral opposite to that of the conventional rifling grooves of said tube and having a depth no greater than the depth of the conventional grooves, a missile to be fired from the gun including an outer portion and an inner portion coaxial therewith for carrying a charge and revolubly carried inside the outer portion, the inner portion having a cap rigid therewith extending outwardly of the inner portion at one end thereof, a plurality of driving bands disposed peripherally of the outer portion of the missile for engagement by the conventional rifling grooves of the tube of the gun, the driving bands being disposed axially on said outer portion in a predetermined axial spacing so that at least one of the driving bands engages portions of the lands which are free of discontinuities when another band is moving through an area in which at least one land is discontinuous thereby to constantly maintain fluid-tightness between the missile and the tube when the gun is fired, and at least one guiding radial vane carried by the outer surface of the cap of the inner portion of the missile for slidably engaging the supplemental groove in the tube.

4. An ordnance system comprising a gun including a tube provided with circumferentially spaced lands forming conventional spiral rifling grooves between them, the lands having discontinuities aligned to form supplemental rifling comprising at least one supplemental groove, said supplemental groove forming with the longitudinal axis of the tube an angle the value of which is selected between zero so that the supplemental groove is substantially parallel to said axis and a small value thereby to form a spiral opposite to that of the conventional rifling grooves of said tube and having a depth no greater than the depth of the conventional grooves, a missile for firing from said tube, the missile comprising an outer portion and an inner portion coaxial therewith for carrying a charge and revolubly carried inside the outer portion, the inner portion having an end portion extending outwardly of the outer portion at one end thereof, a plurality of driving bands on the outside periphery of the outer portion of the missile for engaging the conventional rifling grooves of the tube of the gun, the driving bands being disposed axially on said outer portion in a predetermined axial spacing so that at least one of the driving bands engages portions of the lands which are free of discontinuities when another band is moving through an area in which at least one land is discontinuous thereby to constantly maintain fluid-tightness bea tween the missile and the tube when the gun is fired, at

least one guiding member carried on an outer surface of the outwardly extending end portion of said inner portion of the missile for slidably engaging a corresponding supplemental groove in the tube.

5. An ordnance system comprising a gun including a tube provided with circumferentially spaced lands forming conventional spiral rifling grooves between them, the lands having discontinuities aligned to form supplemental rifling consisting of at least one supplemental groove, said supplemental groove forming with the longitudinal axis of the tube an angle the value of which is selected between zero so that the supplemental groove is substantially parallel to said axis and a small value thereby to form a spiral opposite to that of the conventional rifling grooves of said tube and having a depth no greater than the depth of the conventional grooves, a missile for firing from said tube including an outer portion and an inner portion coaxial therewith for carrying a charge and revolubly carried inside the outer portion, the inner portion having an end thereof extending forwardly of the outer portion, at least one driving band on the outside periphery of the outer portion of the missile for engaging the conventional rifling grooves of the tube of the gun, at least one radially extending guiding member carried by the outer surface of the inner portion of the missile for slidably engaging the supplemental groove in the tube, the inner portion of the missile having a projecting convex surface at an end thereof opposite to said forwardly extending end portion, a piston having a convex face engaging said convex surface and disposed for reciprocable movement between the inner and outer portions and a spring disposed between the piston and the outer portion of the missile urging the piston and thereby the inner portion forwardly with reference to the outer portion with a force adapted to overcome the resistance produced by the air during the flight of the missile.

6. An ordnance system comprising a gun including a tube provided with circumferentially spaced lands forming conventional spiral rifling grooves between them, the lands having discontinuities aligned to form supplemental rifling consisting of at least one supplemental groove, said supplemental groove forming with the longitudinal axis of the tube an angle the value of which is selected between zero so that the supplemental groove is substantially parallel to the axis and a small value thereby to form a spiral opposite to that of the conventional rifling grooves of said tube and having a depth no greater than the conventional grooves, a missile for firing from said tube including an outer portion and an inner portion for carrying a charge and revolubly carried inside the outer portion and coaxial therewith, at least two driving bands on the outer portion of the missile for engaging the conventional rifling grooves, the driving bands being disposed axially on said outer portion in a predetermined axial spacing so that at least one of the driving bands engages portions of the lands which are free of discontinuities when another band is moving through an

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