GB1598034A

GB1598034A - Fire control system for a gun

Info

Publication number: GB1598034A
Application number: GB970978A
Authority: GB
Original assignee: Thales Optronics Ltd
Current assignee: Thales Optronics Ltd
Priority date: 1978-03-11
Filing date: 1978-03-11
Publication date: 1981-09-16
Also published as: FR2419496B1; FR2419496A1

Description

(54) FIRE CONTROL SYSTEM FOR A GUN (71) We, BARR & STROUD LIMITED, a British Company, of Caxton Street, Anniesland, Glasgow, G13 1HZ, Great Britain, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to gun fire control systems.

In a known fire control system for a tankmounted gun an optical device is provided for sighting the target, and the gun and optical device are interconnected by means of a mechanical linkage so that the gun firing or muzzle axis and the line of sight of the optical device are parallel. To operate the fire control system the gunner first visually locates the target using the optical device and centralises a datum mark contained in a graticule in the optical device on the target, the datum mark being accurately aligned with the muzzle axis of the gun. The range of the target is ascertained, for example by using a laser rangefinder, and the optical device is elevated to align a range-related marking on the graticule with the target. The range-related graticule markings are predetermined by the ballistic characteristics of the gun and the missile type to be fired therefrom.With the optical device in this elevated position a missile fired from the gun should hit the target at the range concerned.

A disadvantage of this known system is that the maximum elevation of the optical device, whilst retaining the target in the field of view is severely restricted because of the relatively small field of view provided in the optical device. Thus the effective elevation of the muzzle or bore axis is restricted and hence the range within which a target may be hit, with accuracy, is limited. Attempts have been made in the past to overcome this disadvantage by increasing the field of view of the optical device but this has been accompanied by a reduction in the magnitude of magnification of the target thereby imposing an increased burden on the gunner if accuracy of firing is to be retained.

It is an object of the present invention to obviate or mitigate the above-mentioned disadvantage without imposing any increased burden on the capabilities of the gunner.

According to the present invention there is provided a fire control system for a gun wherein an optical sighting device is adjustable in elevation independently of the gun by a predetermined amount and is mechanically linked to the gun whereby the line of sight of the optical device is either rendered parallel to the muzzle axis of the gun or is altered in elevation by said predetermined amount with respect to the muzzle axis, and wherein the optical device includes a graticule having a first series of markings relating the field of view of the optical device to gun firing range when the line of sight of the optical device is parallel to the muzzle axis of the gun, and a second series of markings relating the field of view of the optical device to gun firing range when the line of sight of the optical device is altered in elevation by said predetermined amount with respect to the muzzle axis.

The alteration in elevation of the line of sight of the optical device is preferably such that the line of sight lies below the muzzle axis of the gun.

The adjustment in elevation of the optical device independently of the gun may be achieved by a variety of different methods.

For example the mechanical linkage may itself be adjustable. Conveniently this may be achieved by altering the length of a member of the linkage such as by having the member telescopic with securing means for securing the telescopic member in one of several predetermined positions. Where the mechanical linkage includes an articulated joint between two members the position of the joint at one of the members may be selectable. In an alternative arrangement the optical device may incorporate a reflector which is pivotally mounted and means for securing the reflector in one of several predetermined pivotal positions.

The first and second series of markings on the graticule may be arranged to be mutually distinct to the eye by physical separation or by distinctive coding or by a combination of both.

The degree of accuracy of the markings in the second series need not be absolute but need only be within the anticipated drift deviation of the missile.

The line of sight of the optical device need not be in the same plane as the muzzle axis of the gun provided that the graticule markings of the first and second series of markings provide a correction factor.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: Figs. 1 and 2 illustrate a gun and an optical device interconnected by a mechanical linkage which is connectable in one of two positions, being in the first position in Fig. 1 and the second position in Fig. 2; and Fig. 3 illustrates the markings on a grati ule forming part of the optical device.

In the drawings, a gun 10 is pivotally mounted on a trunnion 11 forming part of the hull 12 of a tank. The gun mounting 9 forms part of a mechanical linkage 13 which also incorporates a mounting 14 for an optical sighting device 15 mounted on a trunnion 18.

The linkage 13 includes a member 16 which is telescopic, having portions 1 6A and 1 6B which are secured together in a predetermined telescopic condition by means of a pin 17 entering holes, not shown, in the portions 16A and 16B. In the position shown in Fig.

1 the member 16 is relatively short in length such that the linkage 13 is a parallelogram whereby the line of sight 19 of the device 15 lies parallel with the muzzle axis 20 of the gun 10 at all times. In the position shown in Fig. 2 the member 16 is relatively long in length such that the line of sight 19 of the device 15 is despressed by a predetermined amount or angle 0 with respect to the muzzle axis 20. In order that the gunner may distinguish between the two conditions of the member 16 the head of the pin 17 is located on one side of the member 16 in the Fig. 1 arrangement whereas it is located on the opposite side of the member 16 in the Fig. 2 arrangement. This is achieved by virtue of the pin 17 having a tapered body and the holes in the portions 16A, 1 6B being suitably sized.

The optical device 15 includes at a suitable location in its optical path a graticule (or reticule) 22 which incorporates range-related markings as depicted in Fig. 3. Thus the markings are arranged in two series, one appropriate for use by the gunner when the member 16 is in the Fig. 1 condition and the other for use by the gunner when the member 16 is in the Fig. 2 condition. The graticule 22 incorporates a muzzle bore sight mark 30 so located that when the mark 30 is aligned with a target the muzzle axis 20 is likewise aligned.

Beneath this mark 30 (as viewed by the gunner) lies a first series of marks 31 arranged at intervals related to range as denoted in the table of ranges 32. A second series of marks 33 is provided laterally with respect to the marks 31 and arranged at intervals related to range as denoted in the table of ranges 34.

It will be appreciated that in order to utilise the fire control system described herein the gunner proceeds as hitherto with the linkage 13 in the Fig. 1 condition, sets the mark 30 on the target and obtains a target range reading from a rangefinder, not shown. If this range lies within the limits of the table 32 he elevates the optical device 15 until the appropriate mark 31 for the range lies on the target and he thereafter fires the gun which should record a hit. By way of example if the range reading is 15 (i.e. 1,500 metres) the gunner centres mark 31A on the target prior to firing. If, however, the range lies beyond the limit of table 32 but within table 34 the gunner sets the member 16 to the Fig. 2 condition, then elevates the optical device 15 until the appropriate mark 33 lies on the target.By way of example if the range is 3,700 metres the gunner centres mark 33A on the target before firing.

Although the present embodiment has described only two predetermined positions of the member 16 it will be realised that several different portions of this member could be utilised each with a corresponding series of markings (including range related values) on the graticule 22. Also, instead of a telescopic member 16 the articulated joint between the member 16 and either of the mountings 9, 14 could incorporate an eccentric so that the position of the articulated joint may be selectable. Selective pivot locations could be provided for example between the member 16A and the mounting 14.Alternatively, the mounting 14 could be formed of two parts independently rotatably mounted on trunnion 18, one part carrying the optical device 15 and the other part being secured to the member 16 (non-telescopic) with a releasable securing means provided to clamp the two parts in either of two predetermined angular positions. This modification could alternatively be applied to the mounting 9.

WHAT WE CLAIM IS: 1. A fire control system for a gun wherein an optical sighting device is adjustable in elevation independently of the gun by a predetermined amount and is mechanically linked to the gun whereby the line of sight of the optical device is either rendered parallel to the muzzle axis of the gun or is altered in elevation by said predetermined amount with respect to the muzzle axis, and wherein the optical device includes a graticule having a first series of markings relating the field of view of the optical device to gun firing range when the line of sight of the optical device is parallel to the muzzle axis of the gun, and a second series

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. by distinctive coding or by a combination of both. The degree of accuracy of the markings in the second series need not be absolute but need only be within the anticipated drift deviation of the missile. The line of sight of the optical device need not be in the same plane as the muzzle axis of the gun provided that the graticule markings of the first and second series of markings provide a correction factor. An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: Figs. 1 and 2 illustrate a gun and an optical device interconnected by a mechanical linkage which is connectable in one of two positions, being in the first position in Fig. 1 and the second position in Fig. 2; and Fig. 3 illustrates the markings on a grati ule forming part of the optical device. In the drawings, a gun 10 is pivotally mounted on a trunnion 11 forming part of the hull 12 of a tank. The gun mounting 9 forms part of a mechanical linkage 13 which also incorporates a mounting 14 for an optical sighting device 15 mounted on a trunnion 18. The linkage 13 includes a member 16 which is telescopic, having portions 1 6A and 1 6B which are secured together in a predetermined telescopic condition by means of a pin 17 entering holes, not shown, in the portions 16A and 16B. In the position shown in Fig.

of markings relating the field of view of the optical device to gun firing range when the line of sight of the optical device is altered in elevation by said predetermined amount with respect to the muzzle axis.

2. A fire control system as claimed in Claim 1, wherein the mechanical linkage between the gun and the optical device includes two members which are selectively connectable in one of two positions, in one of which positions the line of sight of the optical device is parallel to the muzzle axis of the gun and in the other of which positions the line of sight of the optical device lies below the muzzle axis of the gun by said predetermined amount.

3. A fire control system as claimed in Claim 2, wherein said two members are telecopic.

4. A fire control system as claimed in Claim 2, wherein said two members are mutually articulated and the position of the articulated joint is selectable.

5. A fire control system as claimed in Claim 1, wherein the optical device includes a pivotally mounted reflector, and means for securing the reflector in one of two pivotal positions, in one of which positions the line of sight of the optical device is parallel to the muzzle axis of the gun and in the other of which positions the line of sight of the optical device lies below the muzzle axis of the gun by said predetermined amount.

6. A fire control system as claimed in Claim 1, and substantially as hereinbefore described with reference to the accompanying drawings.