Rammer for a cannon

Abstract: The present invention relates to a method and an apparatus for rapid loading of separate-loading ammunition in artillery guns (1), the shell (20) and propellant charge (21) placed after one another on or in a carrier (11) being accelerated up to a high velocity centred about the longitudinal axis of the gun barrel (1) whereafter the carrier (11) is rapidly retarded to arrest while the shell (20) and the propellant charge (21) are allowed to continue in the direction of the acceleration to their respective ramming positions (3) in the gun.

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for the rapid ramming of shells and propellant charges in medium-calibre or large-calibre artillery pieces which utilize separate loading ammunition, i.e. such ammunition in which the shell and the propellant are not fixedly united with one another to form a unit. BACKGROUND ART For the tubed or barrelled artillery of the 20th century, extremely high rates of fire will be required, since the time between opening fire and up to the point in time when the opponent, after identifying and ranging of the firing gun, is ready to commence combatting this with his own artillery is becoming shorter and shorter. Within the brief space of time which is thus available from opening fire and up to the time when the firing piece must be moved to avoid being knocked out, a sufficient number of shells must, thus, have had time to be discharged in order to have sufficient effect on the target, which, for single targets, may be assumed to be between 3 and 10 rounds. Since the primary consideration in this application is medium-calibre or large-calibre artillery pieces (in other words of a calibre from about 7.5 cm and larger), the weight of the shells will be relatively great, at the same time as there is a main weight difference between the shell and its propellant charge. Automatically loading an artillery gun with cartridged ammunition presents no serious problem, since each cartridge is handled and rammed in the firing position of the gun as a rigid self-contained unit. Granted, the increasingly common, combustible cases nowadays employed in separate-loading ammunition impart to the propellant charges a markedly better stability than the older gun cotton propellant charges, but the combustible cases are nevertheless generally not so rigid that they can carry a shell, for which reason the shell and the propellant charges must be rammed home separately without being fixedly connected to one another. For high firing rates, high ramming speeds are necessary. This, combined with the need for guiding both the shell and the propellant charge during the ramming operation, as well as the large weight difference between shell and propellant charge in turn places particular requirements on how the ramming operation is executed. A relevant prior art is FR-A-0400 386 which discloses a method for ramming separate loaded ammunition, i.e. such ammunition in which the propellant charge and shell are not fixedly connected to one another, in artillery pieces whereby a shell and propellant charge placed after one another in a carrier are aligned with the breech opening of the piece and centred in the main axis of the barrel of the piece in order thereafter to be accelerated in this direction by the aid of a first chaindriven rammer. Said first rammer, however, has not got the ability to deliver the shell and the propellant charge by "free flight ramming", i.e. only by their own kinetic energy, to their respective final ramming positions in the piece. A second rammer is thus used to push the shell and the propellant charge into their final ramming positions once they have entered the breech opening of the gun. This prior art also discloses the preamble of apparatus claim 2 and is considered to be the closest prior art for the method described by claim 1. The main idea behind the present invention is to present a useful method and accordingly an apparatus using the free flight ramming principle and the method and apparatus according to FR-A-0400386 cannot be used for that purpose. A second prior art which may be mentioned in connection with the present invention is GB-A- 262 858 which discloses a hydraulic rammer for artillery pieces comprising a ramming tube in which the shell and the propellant charge are aligned with each other and with the breech opening of said piece and according to which said shell and said charge are supported separately against their rear planes during the ramming operation. A third reference worth to be mentioned is CH-A-662 175 which is disclosing a ramming apparatus for shells which is provided with devices for the adjustment of the ramming force in relation to the elevation of the artillery piece in question. Such an adjustment will also be useful in connection with the present invention. SUMMARY OF THE INVENTION According to the present invention, this problem has been solved in that shell and propellant charge are rammed in a single action from a loading tube in which shell and propellant charge (the latter preferably in the form of a combustible case) are previously arranged in sequence, and this loading tube, on commencement of the ramming operation, is accelerated towards and preferably also so far into the breech opening of the gun that the loading tube enters the chamber of the gun barrel, whereafter the loading tube is retarded so forcibly that the shell and the propellant charge are thrown into the ramming positions of the gun intended therefor. In order that the extreme weight of the shell does not load the propellant charge during the acceleration phase, the loading tube is preferably provided with a collapsible support heel or tooth which is secured in the tube and which abuts against the rear plane of the shell and is collapsed to the side as soon as the shell has passed into the gun barrel and no longer needs its support. In order that the propellant charge (which in itself is relatively light in weight) is not to be retarded by vacuum in the rear inner portion of the loading tube, substantial ventilation apertures must be disposed in the rear region of the tube. In addition; the ramming position of the gun intended for the propellant charge must be provided with a relatively collapsible locking device which prevents the propellant charge from bouncing out again from its innermost position. For acceleration of the loading tube, a chain transmission hydraulic ram can be employed with which accelerations up to speeds of 8-10 m/sec. can be achieved without difficulty. A further detail is the retardation of the loading tube which, thus, must take place from a relatively high velocity over a very short distance in order to impart the correct launching effect to the shell and propellant charge. For such a rapid retardation, use may, for example, be made of one or more hydraulic dampers. Using the above-described ramming apparatus, it is thus possible to achieve a very rapid ramming even of heavy artillery pieces. The systematic concept on which the present invention is based also includes the feature that the loading tube must be reloaded while the originally rammed shell is discharged. This may be affected rearwardly from a magazine of one type or another, e.g. a rotary revolver magazine disposed on the gun in which each chamber either contains both propellant charge and shell or alternatively only the one, in which event several chambers or several magazines must be employed. In order to provide sufficient time for replenishing the loading tube with a new combination of propellant charge and shell, it may be appropriate to employ at least two pendulum-suspended loading tubes which, on pivot arms, are disposed such that they alternatingly may be pivoted in behind the gun to a ramming position intended therefor immediately behind the breech opening of the gun, and to a replenishment or loading position located beside the gun where the propellant charge and shell are loaded into the tube. The loading tube may then be replenished at half the speed with which the gun itself is loaded. As artillery piece in connection with this ramming or loading system, use may be made of an otherwise basically conventional gun with a mechanism of the screw or breech block type, in which event the closing and opening of the mechanism must, however, be controlled by machine in order to make full use of the advantages offered by the rapid ramming process. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The method and the apparatus according to the present invention have been defined in the appended Claims and will now be described in greater detail hereinbelow, with particular reference to the accompanying Drawings. In the accompanying Drawings: Fig. 1 is a side elevation, partially in section, of the breech opening in an artillery piece and a rammer according to the present invention disposed thereat; Fig. 2 shows a perpendicular view of Fig. 1; and Fig. 3 shows an end view of Fig. 1. DESCRIPTION OF PREFERRED EMBODIMENT All parts carry the same reference numerals throughout the drawing figures. However, for purposes of greater clarity, certain parts have only been included in individual Figures. Shown in the Figures is the rear portion of the barrel of an artillery piece 1 provided with a breech opening 2 and a ramming position for propellant charges 3 (only a part of the ramming position is shown in Fig. 1). The ramming position for shells rammed into the gun lies to the right outside the figure. The breech opening 2 of the gun 1 may be closed using a collapsible screw lock 4. In the Figures, reference No. 5 demarcates another part of the elevation system fixedly connected to the gun barrel 1. An angled pendulum pivot arm 7 is movably journalled at this part in a journal 6 adapted for this purpose. In its outer, free end 9, the pivot arm 7, which may be revolved by means of a hydraulic ram 8 (see Fig. 3) carries a journal 10 in which a longitudinally displaceable loading tube 11 is mounted. The loading tube 11 is longitudinally displaceable by means of a chain transmission hydraulic ram unit 12 which, in the short distance which is available (not shown in Fig. 3) , can accelerate a speed of up to 10 m/sec. As will have been apparent from Fig. 1, the chain transmission hydraulic ram unit consists of the hydraulic ram 13 with drive shafts 14, 15, the chain 16, an anchorage point 17 between chain and loading tube and a driving tooth 18 collapsibly secured at the chain and which, in the initial phase, abuts against the rear plane 17 of a shell 20 which lies ready for ramming. The loading tube 11 is also provided with rear buffer abutments 22 which project laterally outside the circumferential surface of the tube. On either side of the journal 10 there are disposed two hydraulic dampers 23 and 24 with their respective abutments 25 and 26. In the rear plane of the loading tube 11, there are provided one or more ventilation apertures which prevent rearward suction within the tube. The positions of the apertures are marked by the arrow 27. In all Figures, the loading tube 11 is pivoted into the ramming position, i.e. in register with and axially centred about the main axis of the gun barrel 1, but in Fig. 3 there is also a ghosted marking 28 for the outward pivoting of the loading tube 11 beside the gun barrel. This position is intended to be utilized on replenishment or reloading of the loading tube. In Fig. 2, a second loading tube 11' suspended on a pendulum arm is indicated by ghosted lines, this tube being in its outwardly pivoted replenishment position. In the starting position, the loading tube 11 is outwardly pivoted about its pivot arm 7 to the position 28 shown in Fig. 3. There, the loading tube is filled or loaded with a propellant charge 21 and the shell 20. The shell 20 is moved in so that its rear plane abuts against the collapsible tooth 18. Between the propellant charge 21 and the shell 20 there is a slight clearance a in this position. If, instead, the twin loading tube 11' had been utilized, the position would have been identical even if the loading tube would, on replenishment, have been located on the opposite side of the gun barrel 1. After replenishment, the loading tube 11 is pivoted by the hydraulic ram 8 in so that it is centred axially about the main axis of the gun barrel 1. Thereafter, the hydraulic ram 13 is activated which, with the aid of its chain transmission, accelerates the loading tube 11 in a direction towards the breech opening 2. During the acceleration, the rear plane of the shell abuts against the tooth 18 and the rear plane of the propellant charge against the bottom of the loading tube 11. When the buffer abutment 22 reaches the abutments 25, 26 of the hydraulic dampers 23, 24, the movement of the loading tube begins to be retarded. This takes place rapidly and in a very short distance of travel. The shell 20 and the propellant charge 21 which lies more or less loosely in the loading tube continue, however, in the original direction of movement, and thereby also into the respective ramming positions in the gun barrel. The ramming force and speed can be governed by selection of that velocity to which the loading tube is accelerated and the rapidity with which the tube is retarded. The movement of the loading tube is so long that its muzzle enters the ramming position of the gun barrel. This imparts to both shell and propellant charge an adequate guiding throughout the entire ramming procedure. When the shell leaves the loading tube 11, the tooth 18 is flipped out so that the propellant charge may pass. Given that the bottom of the loading tube has been provided with the ventilation apertures 27, the formation of a rearward suction is avoided which might otherwise have prevented the relatively light-weight propellant charge from following after the shell into its ramming position. In order to prevent the propellant charge from bouncing out again off the air cushion which is formed between shell and propellant charge, the ramming position of the charge should be provided with a locking device which grasps hold of the charge. As soon as the shell and propellant charge have been rammed home, the screw or breech block 4 is closed and the gun is ready to open fire, while the loading tube is retracted to its outer, replenishment position. Since the retardation of the loading tube is so rapid and the hydraulic ram unit 12 is simultaneously zeroized, the loading tube will rapidly be recuperated to its starting position. As will be apparent from the above disclosures, this system provides an extremely rapid reloading of the piece and consequential fire rate, above all if the piece is provided with two pendulum-suspended loading tubes. Replenishment of the loading tube may be effected from a magazine of the revolver type, from belt conveyors or the like.

Claims: A method for rapidly ramming separate loaded ammunition, i.e. such ammunition in which the propellant charge (21) and shell (20) are not fixedly connected to one another, in artillery pieces having the following consecutive steps a carrier (11) is loaded with a propellant charge (21) and a shell (20) placed after one another in said carrier whereby the rear plane (19) of the shell (20) abuts against a collapsible tooth (18); said carrier (11) containing said shell (20) and said propellant charge (21) is accelerated in a direction towards the breech opening (2), whereby, during said acceleration, the rear plane (19) of said shell (20) abuts against said collapsible tooth (18) and the rear plane of said propellant charge (21) abuts against the bottom of said carrier; said carrier (11) is retarded very quickly to a stationary position when its muzzle end has entered the outer region of the chamber of the artillery piece while said shall (20) and said propellant charge (21) continue the initial movement by their kinetic energy until they reach the rammed position in the gun barrel. An apparatus, in accordance with the method as claimed in Claim 1, for ramming separate loaded ammunition, i.e. such ammunition in which the propellant charge (21) and shell (20) are not fixedly connected to one another, in an artillery piece (1), said apparatus comprising a carrier (11) disposed in the direction of the gun barrel, said carrier being disposed to carry a shell (20) and a propellant charge (21) in series; first means (12-17) for displacing said carrier (11) at high velocity in a direction towards the breech opening (2) of the gun; second means (23, 24) to retard said carrier (11) to a stationary position when said carrier (11) has entered or at least arrived at an immediate proximity to the breech opening of the gun, while the shell (20) and the propellant charge (21) located in said carrier (11) are not influenced by the retardation of the carrier, characterised in that said carrier (11) being designed as a loading tube (11) provided with a rear plane (22) against which the rear plane of the propellant charge (21) abuts during said displacing towards the breech opening and a collapsible support tooth (18) in the front thereof against which the rear end of the shell abuts during said displacing, said collapsible support tooth (18) being so designed that it collapses to the side as soon as the shell has passed into the breech opening (2) of the gun. The apparatus as claimed in Claim 2, characterized in that the rear plane (22) of the loading tube against which the rear plane of the propellant charge abuts during acceleration of the loading tube is provided with ventilation apertures (27) which prevent the formation of a rear suction behind the propellant charge (21) within the loading tube in connection with retardation of the loading tube, and the shell (20) and propellant charge (21) continue forwardly in the earlier direction of acceleration. The apparatus as claimed in any one of Claims 2-3, characterized in that the loading tube (11) is displaceably journalled in a cradle (10) which also carries a chain transmission hydraulic ram (13) for acceleration of the loading tube in a direction towards the breech opening (2) of the gun (1), and one or more hydraulic dampers (23, 24) for retarding the linear movement of the loading tube (11). The apparatus as claimed in Claim 4, characterized in that said cradle (10) is in its turn pendulum-suspended on a pivot arm (7) with which the cradle (10) and loading tube (11) may, from a first loading position (28, 11') beside the gun barrel, be pivoted into a second ramming position with the loading tube (11) axially centred about the main axis of the gun barrel (1).

Inventors: BERGLUND BENGT, BERGLUND, BENGT
Applicants: BOFORS AB
Application year: 1993
Main classification: F41A9
IPC codes: F41A9