Arrangement with release system, ammunition unit and release system

Abstract: The invention relates to an arrangement indicating the type of ammunition, an ammunition unit with such an arrangement and a release system adapted thereto. The invention makes it possible to identify the type of ammunition for ammunition units mounted in position in the release system. The arrangement indicating the type of ammunition includes electronic means (3) with different electrical characteristics depending on the type of ammunition. The different electrical characteristics can be produced by changing impedance.

Description: The present invention relates to an arrangement in release system and mounted on or in an ammunition unit for indicating the type of ammunition which the ammunition unit contains. Each ammunition type is allocated a distinguishable specific indication. The arrangement comprises electronic means with different electrical characteristics depending on the type of ammunition to be indicated. The invention also relates to an ammunition unit with an arrangement according to the above, and a release system with such ammunition units. The ammunition unit comprises a number of ammunition charges, means for activation of the ammunition charges and an arrangement according to the above for indicating the type of ammunition which the ammunition unit contains. The release system comprises at least one release unit with magazine for a number of ammunition units according to the above and a control unit for coupling electrical current to the ammunition units. Known arrangements for indicating the ammunition type can consists of colour marking of the ammunition units, preferably in connection with the electrical connection at the bottom of the ammunition unit. The colour marking makes it possible, for example, for flares to be distinguished from radar chaff and different types of flares or radar chaff charges can be similarly distinguished from one another. On loading the release system release units with ammunition units, the operator must take care that the different ammunition units reach the intended place in the magazine of the release unit on the basis of the colour marking. The places are predetermined. Since the loading must often be carried out under time pressure and difficult external conditions such as darkness, there is a risk of mistaking the ammunition types. The predetermined distribution of the ammunition types also involves limits in the possibilities of matching the ammunition to the prevailing threat situation. Another arrangement for indicating the ammunition type is known from US-A-4 068 556. The arrangement, which is included in a release system, is intended for rockets and each specific type of rocket is allocated an identification type-specific fixed impedance identifying the rocket type. On the launcher side of the release system the values of the respective identification impedances on the rocket or ammunition side are identified in a impedance network including a voltage indicator connected to a computer. One problem with the identifying solution according to the preceding paragraph is that contact impedances are present in the connections between the launcher part and the ammunition part and in included switches. These contact impedances may partly or totally destroy the identification procedure. By allotting each type of ammunition an enlarged impedance interval this problem may be partly met. In that case, however, the number of different ammunition types possible to identify reduces considerably. US-A-3 814 017 discloses another example of an ammunition identifying procedure. In order to distinguish different types of ammunition each ammunition type is allotted a cartridge-side type-specific impedance. The impedance consists of a resistor or a capacitor. The type of ammunition is recognised by a launcher-side based measuring circuit. Also in this case contact impedances in connections and switches may cause problem similar to that described in connection to US-A-4 068 556. EP-A-1 0 282 394 shows cartridges with a fixed coding depending on the ammunition type. The aim of the present invention is to produce a more reliable and more flexible release system in which the harmful influences of the contact impedances are considerably reduced and which can be used to identify a great number of ammunition types. This is achieved by an ammunition-indicating arrangement which is characterised in that the electronic means of the ammunition unit mounted comprises a status-changing element which repeatably can change over between at least two statuses with different electrical characteristics and the status changes of which are indicative of the type of ammunition in question, an ammunition unit with such an ammunition-indicating arrangement, and a release system for ammunition units according to the invention. The release system is characterised in that a measuring circuit is arranged to sense the status changes of the status-changing element for the associate ammunition units in order to determine the type of ammunition. The invention makes it possible for a number of types of ammunition to be mixed arbitrarily in a magazine of a release unit in a manner which is not specified in advance. The identification of the type of ammunition and its positions is first carried out when the ammunition is located in position in the magazine of the release units. On the command to release a certain type of ammunition, the release system addresses positions for this type of ammunition and at the same time the addressed positions are marked as positions in which ammunition has been used. If desired, the ammuntion status can be determined again by a repeated identification operation. According to a preferred embodiment of an ammunition type-indicating arrangement the status changes can be initiated by external electrical influence. According to another preferred embodiment of an ammunition type-indicating arrangement, the number of status change-overs following initiation of the status-changing element indicates the ammunition type. According to a further preferred embodiment, the number of status change-overs from a first status to a second status following the initiation of the status- changing element indicates the ammunition type. The different electrical characteristics are advantageously produced by changing impedance. According to an advantageous embodiment of the ammunition unit, the ammunition type-indicating arrangement is connected at the same contact points as the means for activating the ammunition charges. This embodiment makes it possible to use the same relatively weak current which is connected for controlling the means for activating the ammunition charges for identifying the ammunition. According to another embodiment of the ammunition unit, the ammunition charges are arranged in a cartridge which has a bottom plate with connecting elements in the form of connecting rings and possibly a central connection surface for external electrical connection of the ammunition unit. The ammunition type-indicating arrangement is connected between two of the said connecting elements, that is to say between two rings or one ring and the central connection surface. By utilising a cartridge design known per se, see SE C 7414669-7, the ammunition type-indicating arrangement can be easily connected to the release system. According to one embodiment of the release system, a measuring circuit is arranged for sensing the status changes of the status-changing element for the incoming ammunition units in order to determine the type of ammunition. The number of status change-overs or change-overs of a certain type detected by the measuring circuit indicates the ammunition type. The invention will be described in greater detail below with reference to the attached drawings, in which Figure 1 shows in a basic diagram form a first embodiment of an arrangement indicating the type of ammunition, Figure 2 shows in basic diagram form a modification of the arrangement shown in Figure 1, Figure 3a shows in a cross-section and Figure 3b shows in a bottom view an example of an ammunition unit according to the invention, Figure 4 shows in a basic diagram form an example of a release system adapted for ammunition units with arrangements indicating the type of ammunition, Figure 5 shows a measuring circuit used in the release system, and Figure 6 illustrates how the measuring circuit senses incoming signals. The arrangement indicating the type of ammunition shown in Figure 1 is constructed of two parallel branches 1, 2. One branch 1 contains a switch 3. The switch 3 can be arranged to be either closed or open in its initial and normal position. In the other branch 2, an energy storing circuit 6 in the form of for example a capacitor arrangement is located. The energy storing circuit 6 is connected to a logic and memory circuit 7 for feeding energy to and activating the logic and memory circuit 7 which on activation controls the change-over of the switch 3 between closed and open connection. In the memory part of the logic and memory circuit 7, the information about the type of ammunition for which the arrangement is intended is stored. The memory part can be programmed for this purpose by strapping or programming for, for example, a value corresponding to the number of to or fro change-overs which the switch 3 will carry out with external initiation of the arrangement. On the basis of the information stored in the memory part, the logic part in the logic and memory circuit 7 controls the course of the switch-over of the switch 3. When a current is connected to the terminals 8, 9, the arrangement responds with a change in resistance which can be detected at terminals 8, 9. The detection is described in greater detail below with respect to Figure 5 and 6. A so-called squib or fuse head 10 for activating the ammunition for which the arrangement indicating the type of ammunition is intended, is shown with separate connecting terminals 11, 12 for separate connection to a release unit in the release system. A dot-dashed line 13 marks the boundary between the release unit 24 and the ammunition unit 14 in a release system. The embodiment described above with reference to Figure 1 requires four connecting terminals 8, 9, 11, 12 between an ammunition unit 14 and a release unit 24. Figure 2 shows an embodiment which only requires two connecting terminals. According to this embodiment, the so-called "squib" or fuse head 10 is coupled to the same connecting points as the arrangement indicating the type of ammunition. For the rest, the arrangement can be constructed in accordance with that described above with reference to Figure 1. By coupling in a relatively weak current at terminals 8, 9, the squib 10 can be operationally tested, on the one hand, and the information on the type of ammunition can be obtained, on the other hand. When a stronger current is coupled in, the squib is heated up to an explosion-triggering level and the ammunition is released. A proposed embodiment of an ammunition unit is shown in Figure 3a and 3b. Figure 3a shows a vertical section through the ammunition unit and Figure 3b shows a bottom view. The ammunition 15 is accommodated in a cartridge 16 with circular cylindrical shape. The cartridge bottom 17 is constructed of a plane plate provided with a number of contact elements in the form of contact rings 18, 19, 20 and a central contact surface 21. In the space nearest to the cartridge bottom, on the one hand a so-called squib 10 and on the other hand the arrangement 22 indicating the type of ammunition are mounted. The embodiment described with reference to Figure 1 is connected to four contact elements whilst the embodiment according to Figure 2 is connected to two contact elements. If a common earth is allowed, the number of connected contact elements can be reduced to three in the embodiment according to Figure 1. A release system is shown in basic diagram from in Figure 4. From a control unit 23, a number of release units 24, 25 comprising magazines, not shown, for ammunition units are controlled. There is an operating unit 26 and a display unit 27 for communication with an operator. The release system contains a measuring circuit 28 which is included as part of the control unit 23 as marked by a dashed box in Figure 4 or can constitute a wholly or partly separated unit. According to Figure 5, a sampling circuit 29 senses a signal present between connecting terminals 8 and 9. The sampled signal is supplied to a comparator arrangement 30 partly directly and partly via a delay and hold circuit 31 which delays and holds a sampled signal for one sampling interval. When the input signals of the comparator arrangement 30 deviate to a certain level, the comparator arrangement outputs a pulse which is counted in the counter 32. After completed counting, that is to say a stable position for a relatively long time, the type of ammunition can be unamiguously identified for the ammunition unit in question. The positions of the different ammunition types are stored in a memory 33 in the form of a table from which the different types of ammunition can be unambiguously identified on the basis of the counting results given by the counter 32. Figure 6 shows an example of how the input signal of the measuring circuit 28, that is to say of how a signal detected between connecting terminals 8 and 9, can look as a function of time t. The Y axis represents an electrical quantity A which is based on impedance, that is to say resistance, capacitance or inductance. The signal is sampled at equal intervals at least at the rate described by the sampling theorem. In Figure 6, solid dots 34 mark examples of sampling times. The invention is not limited to the embodiments shown in the above examples but can also be subjected to modifications within the scope of the claims following hereinafter.

Claims: Arrangement in a release system and mounted on or in an ammunition unit for indicating the type of ammunition which is contained in the ammunition unit, each type of ammunition being allocated a distinguishable specific indication, the arrangement comprising electronic means with different electrical characteristics depending on the type of ammunition to be indicated, characterized in that the electronic means of the ammunition unit mounted arrangement comprises a status-changing element which repeatably can change over between at least two statuses having different electrical characteristics and the status changes of which are indicative of the type of ammunition in question. Arrangement according to Patent Claim 1, characterised in that the status changes can be initiated by external electrical influence. Arrangement according to Patent Claim 1 or 2, characterised in that the number of status change-overs following initiation of the status-changing element indicates the type of ammunition. Arrangement according to Patent Claim 1 or 2, characterised in that the number of status change-overs from a first status to a second status following initiation of the status-changing element indicates the type of ammunition. Arrangement according to any of the preceding patent claims, characterised in that the different electrical characteristics are produced by changing impedance. Ammunition unit comprising a number of ammunition charges, means for activation of the ammunition charges and an arrangement mounted for indicating the type of ammunition which is contained in the ammunition unit, characterised in that the arrangement for indicating the type of ammunition is made up of an arrangement according to any of the preceding patent claims. Ammunition unit according to Patent Claim 6, characterised in that the arrangement for indicating the type of ammunition is connected to the same contact points as the means for activating the charges. Ammunition unit according to one of Patent Claims 6-7, whereby the charges are arranged in a cartridge which has a bottom plate with connecting elements in the form of connecting rings and possibly a central connecting surface for external electrical connection of the ammunition unit, characterised in that the arrangement for indicating the type of ammunition is connected between two of the said connecting elements. Release system comprising at least one release unit with magazine for a number of ammunition units according to any of the preceding Patent Claims 6-8 and a control unit for coupling electrical current into the ammunition units, characterised in that a measuring circuit is arranged to sense status changes of the status-changing element for the associated ammunition units for determining the type of ammunition. Release system according to Patent Claim 9, characterised in that the measuring circuit comprises a sampling circuit and a comparator arrangement, which comparator arrangement is arranged to compare two samples following one another and given by the sampling circuit for identifying status change-overs.

Inventors: HOLMSTROEM PETER, LEVISON BJOERN, HOLMSTROEM, PETER, LEVISON, BJOERN, Holmström, Peter, Levison, Björn
Applicants: CELSIUSTECH ELECTRONICS AB
Application year: 1993
Main classification: B64D1
IPC codes: F41A19