GB2251290A

GB2251290A - Shells with fitted cap

Info

Publication number: GB2251290A
Application number: GB8509911A
Authority: GB
Inventors: Joachim Fibranz; Horst Penner
Original assignee: Dynamit Nobel AG
Current assignee: Dynamit Nobel AG
Priority date: 1984-05-23
Filing date: 1985-04-18
Publication date: 1992-07-01
Anticipated expiration: 2005-04-18
Also published as: FR2671622A1; GB2251290B; DE3419110A1; IT1235244B; IT8548044A0; BE902477A

Description

SHELL WITH FITTED CAP The present invention relates to shells which are provided on the side facing away from the propellent charge with a cap which fits on the nose of the shell in form and/or friction fitting manner and surrounds this.

The invention relates chiefly to those rounds of ammunition which, on account of their constructional formation, have a huge freedom of movement of the shell up to the mouth of the barrel and/or possess an especially long nose. Such shells may not always be inserted completely centrally in the barrel and their insertion can lead to undesired rebounding. These disadvantages occur chiefly on insertion of caseless ammunition. Furthermore, a part of the firing gases flows past this into the barrel before the guiding of the shell into the barrel, so that the estimated optimal gas pressure cannot build up. Accordingly, a safer, more defined combustion of the propellant charge powder at the beginning of combustion is not completely guaranteed.

There therefore existed the object of guiding the shell emerging from the casing or - when using caseless munition - from the propellent charge body, centrally in the barrel and preventing the firing gases from flowing past the shell.

In fulfilment of this object, a shell has now been found which is provided on its side turned away from the propellent charge and surrounding the nose of the shell in form and/or friction fitting manner with an applied and releasable cap whose section across the longitudinal direction of the shell in the region of its greatest measurement is circular and makes possible discharge from the cartridge chamber of the weapon.

The cap applied to the shell acts both as guidingand also as sealing element. In weapons with revolving ammunition chambers, as for example are described in DE-A- 28 13 633, it also acts preferably as discharge element with duds which are discharged by following ammunition in nose to nose manner.

The external form of the cap can be chosen as desired within the limits of the conditions set out in claim 1. It can possess the maximum cross section over its entire length or in relation to one or more parts of its length; likewise, the maximum cross section can be arranged at the side turned towards the nose of the shell or at any other desired position. Furthermore, the cross section does not need to be completely circular; it can also be adapted to the form of the cartridge especially within the parts of its length which do not have the maximum cross sectional diameter.

The maximum cross section must not correspond exactly to the calibre of the barrel of the weapon. It can even be sub-calibre, for example if the ammunition chamber possesses a shoulder construction for the cartridge and accordingly an exactly defined position is possible for the cartridge in the cartridge chamber.

The cap then serves less for the positioning of the cartridge but more for the sealing with respect to firing gases. The difference with respect to the calibre of the barrel of the weapon should in such a case therefore as much as possible not amount to more than 5%.

It is furthermore also possible to select the maximum cross section to be super-calibre, especially if the cartridge chamber is formed without shoulder, as is necessary especially on insertion of caseless ammunition.

The cap then also assumes the function of supporting the cartridge as abutment for the firing procedure. In this case, the difference with respect to the calibre of the barrel of the weapon can amount to 50%, depending on which materials are used for the cap. In these cases, especially suitable as material for the cap are those materials which are readily deformable under the temperature and pressure conditions occurring in the ammunition chamber on firing. Such materials are known as such to the man skilled in the art.

The cap is formed of a material whose density is less than that of the material of the shell. Suitable are, for example, thermoplastic, non-combustible substances such as polyethylene, polyamide, polytetrafluorethylene or other thermostable polymers, filled reaction resins and light metals. The caps can also be formed of sintered material which preferably also disintegrates under the pressure conditions of firing.

The density of the material employed should moreover be as low as possible. The indicated materials can also contain additives which give rise to special effects, such as for example materials which increase the sliding capability of the shell which follows or which clean the barrel from deposits.

The cap surrounds the nose of the shell and tightly fits the lateral shell wall on the tapered part of the shell. It is not necessary that it be firmly connected to the entire wall; it must only be guaranteed that a temporary limitable holding on the shell is provided. This holding can take place by means of arrangements known per se, such as for example annular grooves or projections. The holding can also take place with the aid of rivets or lugs, which possess preferably predetermined breaking positions.

The cap according to the invention on the nose of the shell effects a central guiding of the shell into the barrel after firing of the propellent charge during the motion of the shell. As a result of the ammunition chamber gas pressure then building up, it also acts as sealing element and thus reduces the gas loss through the gap between tapered nose of the shell and barrel within the time span before the complete entry of the shell into the barrel. The cap is torn off from the nose of the shell by the gases which have advanced; it leaves the barrel before the shell and, on account of its ballistically unsuitable form as well as its lower weight, is deviated from the flight path of the shell.

It falls a few metres to the ground after leaving the mouth of the barrel.

The invention is explained in the drawings by means of explanatory Examples. There is shown: FIGURES 1 and 2 a schematic construction of the ammunition chamber with entry to the barrel, FIGURE 3 an embodiment with sub-calibre cap, FIGURE 4 an embodiment with sub-calibre cap, FIGURES 5 - 7 embodiments with check means for the cap on the shell.

Figures 1 and 2 show a section through a weapon at the position of the ammunition chamber. In both figures, 1 denotes the shell, 2 the applied cap, 3 the barrel of the weapon. In Figure 1, the cap is sub-calibre, in Figure 2 super-calibre.

In the embodiments shown in Figures 3 and 4, the holding of the cap takes place by means of an annular groove 5 on the shell, in which the turned-in end of the cap engages.

In Figure 5 there are shown two different geometric embodiments of the cap 3 with holding arrangements over the projections 6. In both cases the cap has the maximum crosssectional diameter at the side turned towards the propellent charge powder, with Figure 5a, also at the nose.

Figures 6 and 7 show embodiments in which the cap 3 is held either by a plug 7 or by a transverse pin 8 which can also possess a predetermined breaking position.

The projection 7 can either be formed as the central projection of the cap or can be connected with the cap as special pin. In both cases, corresponding bores are provided in the nose of the shell in which the plugs or pins fit.

Claims

Claims:

1. Shell with a cap which is fitted on its side facing away from the propellent charge and surrounding the nose of the shell in form and/or friction fitting manner and which is separable, the section of which cap across the longitudinal direction of the shell in the region of its greatest dimension is circular and makes possible a discharge from the ammunition chamber of the weapon.

2. Shell according to claim 1, characterised in that the cap consists of a material whose density is lower than the density of the material of the shell.

3. Shell according to claim 1 or 2, characterised in that the cap is fixed to the shell by means of an annular groove.

Amendments to the claims have been filed as follows Claims:

1. A shell of encased or caseless type for emplacing in the ammunition chamber of a weapon and firing therefrom through a weapon barrel whose calibre is matched to that of the shell, the shell having a tapered nose region and being provided with a cap which is fitted as a separate member around the tapered nose region of the shell to cover completely the polar surface of the nose region and lateral surfaces of the shell contiguous therewith, which cap is able to travel through the weapon barrel on firing the shell and achieve therein sealing in the nose region of the shell with respect to propellent gases and is separable intact from the shell on emergence from the weapon barrel without being destroyed as a consequence of firing the shell, which cap has a crosssection varying along the length thereof with the portion which possesses the greatest cross-section transverse to its longitudinal axis being circular with a diameter which lies in the range of from - 95% to + 150% of the value of the calibre of the shell.

2 Z. A shell according to claim 1 er--2, wherein the cap is formed of a material whose density is lower than the density of the material of the shell.

3 A. A shell according to any preceding claim, wherein the cap is fixed to a shell by engagement with an annular groove formed in the shell.

3 4 B. A shell according to claim, wherein a turned over edge portion or an internal rim of the cap engages said groove. 5 ss A shell according to

claime 1

wherein a pin member associated with the cap, having a predetermined breaking position and entering a bore in the shell acts to hold the cap on the shell prior to firing.

67. 8. A shell according to any preceding claim, wherein the cap has its maximum cross sectional diameter at the part thereof which is closest to the propellent charge.

7 8. A shell with cap fitted thereon, to such as hereinbefore described with reference to and as showed in any one of the accompanying drawings.