US2417983A - Ordnance - Google Patents

Description

arch 25, 1947. A T, HOLMAN E1- AL 2,417,983

oRDNANcE- Filed May 19, 1945 5 Sheets-Sheet 1 ffyeyfr's ARTHUR TREVENA HOLMAN THOMAS THOMSON """v" 25, 1947. A. T. HOLMAN ET Al. 2,417,983

ORDNANC E Filed May 19, 1945 5 Sheets-Sheet 4 Mardi 25, 1947. A T HOLMAN ET AL 2,417,983

ORDNANGE Filed May 19, 1943 5 Sheets-Sheet 5 THOMAS THOMSON Patented Mar. 25, 1947 UNITE STTES ORDNAN CE Scotland Applicata@ May 19, 1943,'v serial No. 487,650 In Great Britain May 16, 1941 8 Claims. 1

This invention relates to ordnance and particularly non-ried projectors or guns for use in discharging comparatively heavy projectiles such, for example, as bombs, grenades, flares, depth charges and the like capable of being introduced into the projector or gun barrel, for example, by being dropped through the muzzle.

It has been suggested to discharge such projectiles by burning a charge of cordite in a charge container of high pressure resisting material from which the pressure gases, derived from combustion of the explosive, are rst expanded into a receiver from which they are again expanded into the barrel into which the projectile is loaded and from which it is discharged by the gaseous pressure. In carrying out such a method when the charge begins to burn a pressure of the order of several tons per square inch is rapidly built up in the charge container, the communication between the gas receiver and the barrel being provided through ports or passages of small cross-section.

It has been found, however, that a simplied projector apparatus can be utilised involving only a single stage of reduction of pressure of the combustion gases if these pressure gases are derived from a smokeless propellant powder charge i substantially constant burning surface.

It is the object therefore of the' present invention to provide a projector and cartridge therefor for enabling a projectile to be discharged under the influence of gaseous pressure derived from a cartridge containing a charge of such constant burning surface smokeless powder.

This general object is attained Vby arranging that the propellant charge is caused to burn in a combustion chamber forming part of the projector and the pressure gases generated caused to pass thence through a restricted opening leading from the combustion chamber into the projector barrel as will hereafter more clearly appear.

The invention in its broadest aspect may besaid to consist of ordnance for the discharge of projectiles comprising essentially a barrel, Va combustion chamber adjacent the barrel and communicating therewith through a constricte'd opening, a cartridge receiving breech forming part of the combustion chamber, means for introducing a cartridge into said breech and means for firing said cartridge.

A further important feature of the invention resides in the interposition between the cartridge receiving breech and the restricted opening leading into the barrel of a lter device which, apart ings, of one example of our invention as applied to an anti-aircraft projector and from the appended claims in which latter the term ordnance4 is employed in its generic sense.

In the drawings:

Figures l and 2 are side and rear elevations respectively of a projector constructed in accordance with the invention;

VFigure 3 is an enlarged sectional view taken on the line III- III of Figure 1 showing particularly the firing mechanism and associated parts;

Figure 3a is a section on the line IlIa-IIIa of Figure 3 showing details thereof;

Figure 4 is a sectional plan on the line IV-IV' of Figure 3 showing the breech part set for gas or automatic operation;

Figure 4a is a partial view corresponding to Figure l but with the breech part set for hand operation;

Figure 5 is a part section on the line V-V of Figure 2 to a larger scale showing the range control valve;

Figure 6 is an enlarged transverse section on the line VI-VI of Figure 2 showing details of the cartridge loading device; and

Figure 'l shows in longitudinal section Va cartridge suitable for use with the projector as herein proposed.

Referring to these drawings, the numeral I designates the projector barrel which is `supported from a more or less conventional support or stand 2 about the vertical axis of which the barrel and its associated parts can be swivelled. This barrel is also capable of movement about the horizontal axis of its supporting trunnions 3 to provide for variations of elevation. In the base of the barrel l a chamber 4 is provided. 5 designates the cartridge breech part housing and' is the cartridge breech part having a breech or opening 'i forreceiving the cartridge. The combustion chamber as a whole is constituted by this cartridge breech and the combustion-chamber continuation 8 into which it leads. This chamber 8 may conveniently be constituted by a removable and renewable liner nozzle 9 bridging the division between the barrel base la and the combustion chamber housing 5a, a constricted Venturi opening l leading from the combustion chamber by way of the port II into the chamber 4 in the base la of the gun barrel. A lter or perforated powder trap I2, which is also removable and renewable, is contained within the combustion chamber continuation 8 as best shown in Figures 3 and 4. As the liner nozzle and lter may be liable tocorrosion and erosion the easy replacement of these parts ensures the gun being maintained at its maximum efficiency. The lter I2 performs two functions. It serves to prevent choking of the constricted Venturi opening I0 by any unburnt particles and ensures the combustion of the propellant charge wholly on the pressure side of the opening IU. The total venting area of this lter I2, constituted in the example shown by perforations, should be greater than the area of the constricted exit opening from the Venturi device I0 so that it imposes no effective restriction to the passages of the gases produced during combustion.

In Figures 3 and 4 of the drawings a cartridge containing a propellant charge of substantially constant burning surface smokeless powder is indicated at I3 in position in the breech opening 1, in alignment with the combustion chamber continuation 8 at one end, and with a ring pin 4I of conventional form, at the other endwhich is the position of the parts immediately prior to the ring operation.

Slidable within the breech part housing 5 is the breech part 6. Within one end of the `breech part housing 5 a cylinder I4 is mounted and closed by a c ap closure I5 forming a pressure chamber and within the cylinder I4 a piston I6 is arranged its end I1 bearing on the breech part 6. Leading from any suitable part of the combustion chamber continuation 8 passages 8a lead to the pressure cham. ber I5 s o that, when the cartridge I3 is fired, pressure gases, in addition to acting on the projectile, act on the piston I6 causing it to force the breech part 6 against the influence of the spring I8 to thenposition where the breech, with its spent cartridge case still in position, comes into alignment with a cartridge case ejector I9. In normal operation this cartridge ejector is forced by the compression spring 20 into the breech 1 ejecting the spent cartridge and, by reason of its engagement in the breech 1, the breech part 6 is held in position ready to receive a fresh cartridge.

It will be seen on reference to Figure 4a that the flange 2| on the end of the ejector I9, coming into contact with the extension 22 of the breech part housing 5, will prevent the spring 20, cornpressed between the ejector I9 and the tment 23, from being forced beyond the required distance. It will be seen that with the parts as in Figure 4 the spring I 8 before referred to is in compression between the breech part 6 and the bushing 24 through which a tubular handle 26 can slide.

When the breech part is operated automatically by gas pressure in the manner described, this bushing 24 acts as a stationary abutment enabling the spring I8 to return the breech part 6 to the firing position when a fresh cartridge is inserted and the ejector I9 is forced thereby back out of engagement with the breech 1. This can be effected in two ways. In normal operation itis effected, as before indicated, by the loading 0f a fresh cartridge into the breech 1 as indicated in Figure 4a. If, however, it is desired to return the breech part 6 to firing position without the insertion of a cartridge, this can be effected by withdrawing the ejector I9 by means of the ejector operating handle 21. This handle is retained in position by the screw stud 28 engaging in a recess in its tail.

It will be clearly seen that by means of this handle 21 the ejector I9 can be moved back by hand, a slot 29 being provided in the casing 5 to permit the necessary movement.

If it should be desired, or prove necessary for any reason, that the breech part i5 be also operated by hand,- nstead of by the pressure gases as before described, the stop valve 38 (Figure 4) can be screwed down to close the passages 8a and thus to shut off the supply of pressure gas to the pressure chamber I5.

As before mentioned when operation of the breech part Ii is by gas pressure the bushing 24 is held stationary and acts as an abutment for the spring I8. This is effected by means of a pair of oppositely disposed lugs 3i projecting from the bushing 24 engaging an internal flange 32 having ridges with which recesses 3Ia of the lugs 3I register. The outer end of the tubular handle 26 is provided with a nut closure 33 to which is secured a central rod 34 screw threaded at its inner end into a conical boss 35. The inner end of the tubular handle 26 is slotted at 36 and screw threaded into the breech part 6, a key 31 serves to prevent relative movement between the boss 35 and the tubular handle 28 when the rod 34, by turning the nut 33, is screwed into the boss. The rod 34 in addition to serving to connect the component parts of the handle as a whole together also causes the boss 35 to expand, or tend to expand, the inner screw threaded end of the tubular handle 26 into rm engagement with the corresponding screw thread in the breech part 5.

It will now be clear that if the disc Wheel 38 connected to the bushing 24 be first pushed in against the influence of the spring I8 'to carry recesses 3 Ia of the lugs 3I free of their co-operating ridges on the supporting ange 32, the bushing 24 can be easily rotated and if so rotated through an angle of the lugs 3| will come into register with slots 39 cut through the interna] flange 32 so that the lugs 3| can pass through these slots and the spring I8 is thus put out of effective action and the breech part can thereafter be actuated by hand. Figure 4a shows the position of the parts when the above operations have been performed.

Hand charging of the gun may be effected by directly inserting a cartridge into the opening 40, or, preferably, a mechanical loader and extractor may be employed. Such a device is indicated at L in Figures 1 and 2 and in cross-section by Figure 6. The loader comprises a funnel shaped tubular opening LI into which the cartridge is first placed. A sloping way leads from LI to the trough L2 in which is .an arcuate ramming member Ll3 normally in the forward or breech end position. The member L3 has an upwardly eX- tending rod L4 at the upper end of which is fixed a downwardly depending tubular shuttle handle L5 which surrounds a compression spring L6 in contact with a saddle member L1 which can slide on rods L8 xedly mounted between a base plate bolted to the breech part housing 5 and an cuter plate.

the spring L6. This releases the member L3 which is then drawn outwardly. The cartridge then falls into the trough L2 and the handle is then sharply pushed to the breech end of the loader. This rams the cartridge home, `the ejector I9 is pushed out of the breech 1 by the incoming cartridge, the part 6 is thereupon released and slides immediately into the ring position.

On return of the breech part to the charging position (either by pulling on handle 6a if hand operated or by piston I6 if gas operated) the ejector I9 forces the cartridge case out through opening 4U. This causes a hooklike lip L9 on the member L3 to catch on the outstanding edge of the empty cartridge case head. If the handle L5 is now withdrawn the cartridge case will be fully extracted and will fall through opening LIO free of the loader. In the meantime a new cartridge, if already inserted in the opening LI, will fall down in the trough L2 in front of ram L3 and can then be driven into the breech on return of the handle to its normal inward position.

It will thus be seen that rapid ring may be maintained by either method of operating the breech.

After a cartridge has been inserted into the breech 1 through the opening 4l) and the breech has been returned to ring position in alignment with the firing pin 4 I, firing is effected by operation of the tiring handle 42 supported on one side of .the barrel l, a manipulating handle 43 being provided on the other side of the barrel so that the operator can conveniently train the projector on the target, suitable sighting arrangements being provided.

The sighting arrangement shown in Figures l and 2 consists of ya rod 44 hinged about a pivot 44a, rendered capable of having its angle adjusted for various specified ranges by connecting the linked arm 45 to diierent positions on the calibrated plate 46 as clearly shown by Figure 1 of the drawings.

The range according to the invention can be varied between maximum and minimum limits by providing an opening leading from the expansion chamber 4 and by-passing a proportion of the pressure gases by Way of the conduit 41 to a position adjacent the muzzle of the barrel. The effective range will depend on the amount of the pressure gas so by-passed and this can be controlled by a valve 48 (see Figure 5), which is shown with its operating handle 48a in full lines corresponding to the position of the valve when fully open for minimum range, the handle being turned to the dotted line position when the valve will be fully closed for maximum range. Settings of the valve intermediate these extreme positions will provide for intermediate ranges.

Firing is, as before indicated, eiected in the example illustrated by partially rotating the handle 42 about the supporting hollow pivot bar 49 against the influence of the torsion spring 50 (refer to Figures 3 and 3a), whereupon the cam 5| on the boss of the handle operates upon the top of the trip pawl 52, forcing it and the firing `rod 53 down against the influence of the spring 54, the trip pawl being in engagement with the top of the ring rod 53 at 55 as shown clearly by Figure 3 of the drawings. The pawl 52 is guided in its bodily downward movement by the studs 56 ridingV down the slots 51 (see Figure 3a) and when it reaches the limit of its bodily downward movement the projection 58 comes into contact with the shoulder 59 of the ring rod bracket, disengagesthe catch 55, and thus trips the pawl, the partial rotation of which causes the pawl to press upon the top of the pawl return plunger 60 so that immediately the firing mechanism has been operated in the manner hereafter described the return plunger 60 resets the trip pawl for engagement with the firing rod ready for the next firing operation. Y

The actual ring operation is effected by the ring rod 53 forcing down the casing 6l which encloses the spring 54, whose lower end engages one end 62 of the rocking lever 63 whose other end 64 engages the bell crank loading lever 65 and forces inwardly the firing hammer spring sleeve 66 of the known conventional percussion firing device. tiring device is well known to those skilled in the art and therefore needs no elaborate description, it being suiicient to say that the axial movement of the sleeve 66 stores energy in the spring 61 until this movement trips the catch 68 whereupon the spring 61 shoots the ring hammer 69 for- Ward and causes the ring pin 4i to strike the percussion cap of the cartridge. For use in emergency an emergency firing plunger 10 mounted to slide in a sleeve 1| canbe provided.

In order to prevent unauthorised operation of the normal firing mechanism a movable safety catch indicated at 12 may be provided capable of being interposed beneath the flanged cup-like element 12a carried on the firing rod 53. This anged element 12a also acts as a water guard to prevent water entering the mechanism. The extension 13 of the ring rod by co-operation with the recess 14 in the breech part 6 is for the purpose of preventing the firing gear being operated except when the breech part is in correct position, the latter together with the cartridge containing breech 1 and its contained cartridge being then in precise alignment with the expansion chamber 8.

The extension 13 and the recess 14 can, however, be used for a secondary purpose. If the recess 14 be made part of the lubricating system and is full of lubricant the lower end of the firing rod extension 13 will act as a plunger pump, and each time the ring gear is operated will effect forced lubrication, forcing the lubricant through any passages connected with the recess 14 and leading to parts to be lubricated as indicated at 15 and 16.

To lessen shock when the breech part 6 contacts with its casing `5 on returning to the charging position, shock absorbing pads may be provided as at 6b in Figures 4 and 4a. Any gas trapped in the chamber I5 acts in a similar capacity in the reverse direction.

. For the eiective operation of a projector of the kind hereinbefore described, the construction and nature of the cartridge employed is of importance. In particular the propellant employed should be a smokeless powder charge of constant burning surface and conveniently consists of what is known in th-e explosives art as tubular or "strip powder. The characteristics to be observed in practice in the case. of the tubular form is that the powder should be of non-porous nature and of a singly annular form having a uniform annular thickness greatly exceeded by its length; or if of strip or rectangular solid form the thickness must be greatly exceeded by the length and breadth. A suitable construction of cartridge is illustrated in Figure 7, 'E1 being the cartridge wall, 1B the metal cartridge head, 19 the base wad and 80 a bag containing black The operation of this percussionV powder. The tubular smokelesspowder charge is indicated at 8l and 82 is a celluloid ydisc over which the wall 'l1 is peripherally turned as indicated at 83. 84 is a percussion cap chamber, 85 is the cap and 86 the anvil.

It is to be understood that the web thickness and composition of the powder will be varied depending on the performance required, these factors being so chosen in relation to the areaof the restricted orice l leading into the projector barrel, as to ensure that a pressure is built up at which the propellant charge will burn satisfactorily and at the same time the necessary or desired flow of gas will be maintained during 'the travel of the projectile up the gun barrel to give the desired velocity of discharge.

The volume of the propellant charge must be considerably less than the volume of the combustion chamber in which it burns. Taking an example and assuming a projector for disch'arg ing projectiles of 2 lbs. Weight and the projector barrel has an internal diameter of 2.875 inches and an'effective length of projectile travel of l feet the normal angle of projection being 75 to the horizontal; the combustion chamber when empty should have a total capacity of about cubic inches and be connected with the barrel through a constricted opening of 0.5 inch diameter. The breech should be such as to accommodate a cartridge case of 1 inch diameter and 3.7 inches long. A satisfactory result will then be attained if the bag 80 has a charge of 20 grains of black powder and the longitudinally disposed propellant charge consists of 16 grams of smokeless powder of constant burning surface.

A suitable composition for this smokeless powder charge consists of Per cent Nitroglycerine 29.5 Nitrocellulose 65.0 Diethyldiphenyl urea 2.0 Mineral jelly 3.5

in the form of tubes of web thickness of 0.011 inch and internal diameter of 0.057 inch.

When such a cartridge is iired it builds up in the combustion chamber a maximum pressure in the region of 2,500 lbs. per square inch and gives in the projector barrel a pressure in the region of 600 lbs. per square inch and this will be found eiective to project the 2 1b. projectile to a height of approximately 2,000 feet. Experience has shown that if, instead of a 2 lb. projectile, one weighing 3 lbs. of the same diameter is used the projector is effective to discharge this heavier projectile to a height of approximately 1,500 feet. A projector of the foregoing character has proved an eiective defence against low ilying or dive bombing aircraft but ordnance of the same general construction and coming within the terms of the appended claims can be used effectively for vother purposes, for example as a device for discharging anti-submarine depth charges.

Such a projector with its barrel inclined at an angle of 43 to the horizontal has served to hurl a depth charge weighing 65 lbs., attached, of course, to a device for insertion into the barrel, a distance of 600 feet. In this case the combustion chamber when empty had a capacity of 11 cubic inches, the constricted throat opening leading into the barrel was 0.55 inch in diameter and the cartridge used was 1.5 inches in diameter and 3.8 inches long.A The amountof black powder employed in the cartridge was 30 grains and the longitudinally disposed propellant charge was 33 grams in the form of tubes of web thickness of 0.030 inch and internal diameter of 0.025 inch. In this example a maximum pressure of some 2,500 lbs. per square inch was built up in the combustion chamber.

In the case of a projector for discharging bombs, salvos of two or three can be projected simultaneously, each bomb of the salvos being discharged to a different height and practical experiment has shown that with a salvo of three bombs discharged simultaneously from a projector as particularly described herein the centre of the salvo will be 550 feet and nearest burst at 450 feet from the projector. 1 The ringof ordnance made in accordance with our invention is attended by no flash and only by a comparatively gentle recoil. Many of its parts can be made from cheap readily available Ymetal such as cast iron. The apparatus is possessed ofthe mobility and convenience, and it has been found to possess the outstanding advantage of regularity in performance.

`The foregoing is to be taken only as by way of illustration and exemplication of the invention as it is obvious that ordnance in accordance with theinvention may be varied and modified in many ways within the scope of the appended claims, in which the term ordnance is, as before indicated, to be construed in its generic sense except that the present invention is not con cerned with apparatus for the discharge of torpedoes.

Finally it is to be observed that maximum success in the operation of the invention depends largely on the use of a correctly designed cartridge, the dominant factors of which are that its propellant charge of substantially constant burning surface smokeless powder must be considerably less in volume than the volume of the combustion chamber in which it is to be burnt and this charge must be so related to the combustion chamber volume and the area of the constricted opening leading into the projector barrel vthat the pressure created in the combustion chamber must undergo a reduction in such a ratio-for example 4 or 5 to 1-that while the pressure generated on the pressure side of the constricted orifice permits of satisfactory combustion the reduced pressure and ilow of the gases in the projector barrel are such as to ensure a satisfactory propulsion effect on the projectile. It is obvious the precise conditions will vary from time to time both with the projector construction and the particular composition of the propellant charge, but with the foregoing read in conjunction with the information and examples given herein those skilled in the explosives art will be able readily to design suitable cartridges for any given set of conditions.

What we claim and desire to secure by Letters Patent is:

l. Ordnance for discharging projectiles comprising a barrel, a combustion chamber permanently communicating through a restricted opening with the barrel at a position below that at which the projectile to be discharged is introduced into the barrel, ring mechanism in alignment with said combustion chamber, a breech part -slidable relative to the combustion chamber continuation, a cartridge receiving breech in said breech part said breech forming part of the cornbustion chamber when in alignment therewith, a cartridge ejector offset with respect to the axis of said chamber, and means for moving said breech part relatively to and from one position in alignment with the combustion chamber at one end and firing mechanism at the other and to and from a second position in alignment with said cartridge ejector.

2. Ordnance for discharging projectiles corn'- prising a barrel, a combustion chamber permafnently communicating through a restricted opening with the barrel at a position below that `at which the projectile to be discharged is introL duced into the barrel, a breech part slidable relative to the combustion chamber, a cartridge receiving breech in said breech part, a cylinder iixedly mounted with respect to said breech part'. a piston in said cylinder for moving said breech part in one direction, a passage for conducting?`d proportion of `the combustion gases generatedfby the firing of the cartridge to the cylinder for operating upon said piston to move the breech part from firing position to cartridge ejecting position, a spring actuated ejector aligned with said breech part in cartridge ejecting position and entering the same to eject the spent cartridge and to retain said breech part in such ejecting position, means operable to insert a loaded cartridge into the breech thereby retracting said ejector and releasing said breech part, andina spring for returning the loaded breech part into ring position.

3. Ordnance according to claim 2 having a Valve for cutting olf the supply of the combustion gases to the cylinder containing the breech part operating piston for facilitating hand operation of the breech part moving and cartridg ejection mechanisms. f-

4. Ordnance for discharging projectiles by means of a propellant charge of constant burning surface smokeless powder, comprising a barrel, a combustion chamber constituted by a cartridge chamber portion leading to an aligned combustion chamber continuation of a larger diameter, which combustion chamber continuation terminates in a restricted opening leading directly into the barrel at a position beneath the projectile to be discharged, a Venting filter located in the combustion chamber continuation so as to be interposed between the cartridge chamber and the restricted opening, and a ring mechanism, the cartridge chamber, combustion chamber continuation filter, and firing means all being in alignment at the firing position.

5. Ordnance according to claim 4, wherein the restricted opening is for-med at one end of a removable nozzle lining the combustion chamber continuation whereby to provide for replacement of said nozzle.

6. Ordnance according to claim 4, wherein the filter has a venting area greater than the area of the restricted opening between the combustion chamber and the barrel.

7. Ordnance according to claim 4 having a conduit leading from the barrel at a position beneath the projectile to be discharged and reentering said barrel adjacent the nozzle thereof, and a valve controlling the flow of pressure gases through said Vconduit to control the firing range.

8. Ordnance for discharging projectiles, comprising a barrel, a combustion chamber adjacent the lower end of the barrel and communicating therewith, a removable liner for said combustion chamber, formed at one end with a constricted opening leading to the barrel and at its other end with an inwardly directed ange, a tubular lter extending into said'combustion chamber and having an outwardly directed flange engaging behind the flange of said liner and retained in assembled position by a closely fitting stepped ange extending inwardly from the inner wall of said combustion chamber, a cartridge receiving breech -aligned with and forming part of said combustion chamber in firing position, means for iiring a cartridge inserted in said breech, and means for moving said breech out of alignment with said combustion chamber after firing. to a position in alignment with a cartridge ejector and re-loader.

ARTHUR T. HOLMAN. THOMAS THOMSON.

REFERENCES CITED The following references are of record in the tile of this patent:

UNITED STATES PATENTS Number Name Date 1,328,021 Thornycroft Jan. 13, 1920 321,042 Lyman June 30, 1885 1,756,079 Anderson Apr. 29, 1930 2,286,764 Scott-Paine June 16, 1942 1,559,183 Rimailho Oct. 27, 1925 FOREIGN PATENTS Number Country Date 126,071 British May 8, 1919 17.994 British Of 1894

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