GB2094449A - Decoupled weapon drive - Google Patents

Abstract

An apparatus for aiming a weapon mounted on a mobile carrier comprises the following features in order to eliminate the influence of travelling motions of the carrier on the aiming procedure: the weapon (1) is supported at its centre of gravity on the carrier in a manner substantially free of bearing forces; a high-speed power drive (9), e.g. a traction motor or a flywheel energy storage means, is mounted on the carrier; and an table rotary coupling (4), for example a continuously-slipping slip clutch, is interposed in a drive transmission between the high-speed power drive (9) and the weapon (1) to transmit to the latter an aim-adjusting torque independent of the speed of rotation of the power drive. For rapid follow-up or aiming movements (coarse aiming) an additional solidly- engageable and releasable friction clutch (3) is disposed in the same or additional drive transmission. <IMAGE>

Description

SPECIFICATION Decoupled weapon drive This invention relates to means for aiming an inert mass, for example a weapon, mounted on a movable carrier, for example a vehicle. Movable combat vehicles in particular have proved to coffer advantages as compared to vehicles used for fighting from a fixed position in that they are less likely to be hit. Yet it is a condition for their useful deployment that such moving combat vehicles can be fired with accurate aiming while travelling.

So far, means have become known by which such weapons can be stabilized to a limited degree with respect to rotation about two or three axes in space. This is a difficult task to fulfill as the aiming moments must be supported by the cheeks of the moving carriage. It would greatly simpiify matters if the concept of the vehicle were such that the weapon would have to follow up an aiming command signal only in accordance with one axis of rotation. A particular difficulty is encountered with weapons which are stabilized about several axes in that aiming movements of the weapon during relative movements of the body must be supported by the moving body at a time when especially accurate aiming is of utmost importance.Manufacturers of stabilized weapon systems, who argue that a great mass, such as the turret of a tank, remains in its position in space under inertia and, therefore, stabilizes itself automatically, are correct only so long as aiming procedures need not be initiated. However, as soon as the inherent motion of the vehicle requires a great mass to be moved vertically and horizontally in an aiming procedure, the situation is quite different, even when aiming at a fixed target.

Since movable combat vehicles can turn faster about their vertical axes than can conventional turrets, it is useful to stabilize the weapons of such vehicles with respect to the trunnion axis only, or to have them follow an optical system adapted to be stabilized.

In weapons with a flat trajectory, rotation about the roll axis (longitudinal axis), known as canting, can be eliminated by means of computers by correcting the angle of attack of the weapon. The subject matter of the invention is concerned with supporting the forces of reaction in aiming motions of the weapon.

If a barrel-type weapon is suspended at its centre of gravity which lies on the trunnion axis, the weapon is balanced about the trunnion axis and no torque is imposed on the weapon when the vehicle undergoes acceleration or deceleration.

The weapon is decoupled from rotation movements of the vehicle body about the pitch axis (transverse axis) and, because of its inertia, is not caused by such movements to leave its position, disregarding the minor bearing frictional forces. However, during elevational aiming procedures, forces of acceleration must be transmitted to the weapon. It is known to react these forces against the vehicle body by mechanical, electrical, hydraulic or other adjustment members.

It is an object of the invention to apply the required moments of reaction for the aiming procedure without including the relative movements of the vehicle body in the stabilizer system in the transmission of power.

The present invention, in its broadest concept, provides various arrangements in which the weapon or other inert mass is freely pivotally supported about at least one axis, for example the trunnion axis, and is provided with at least one rotary coupling element, for example a slip clutch, through which aiming torques can be transmitted to the weapon or mass from a driving means, with the elimination or reduction of the transmission of movements of the vehicle body or other carrier (through the coupling element) to the weapon or other mass during the aiming procedure.

A slip clutch, for instance, suitable for use as the coupling element, may take the form of a mechanical disc brake, multiple-plate brake or shoe brake, an electrical eddy current coupling, a hydrodynamic coupling, or a one-stage power distributing planetary gear including a hydrodynamic retarder in one arrangement of which the sun gear is connected to the rotor of the hydrodynamic retarder, whost stator is fixed to the carrier body, the ring gear of the planetary gearing being connected to the weapon or mass and the satellite (planet pinion) carrier being driven by a drive arrangement in the vehicle body.

The primary (input) end of one of the clutch embodiments mentioned above may also be driven by a flywheel which is decoupled from the carrier body about its axis of rotation and disposed on the trunnion axis.

In the case of the embodiment in the form of a planetary gear with hydrodynamic retarder, the satellite carrier may be driven by the flywheel.

Power transmission by means of a flywheel requires no accelerating and slipping mode of operation of the clutches. Yet it must be ensured that the trunnion axis is decoupled from the body and the feed motor of the flywheel is not driven during the stabilizing process.

The numbers of revolutions per minute, i.e. the angular speeds, at which the primary ends of the slipping clutch members are driven must be much higher than the angular speeds resulting from the pitch oscillations of the vehicle body. When applying this principle, the excitation of oscillations tending to become transmitted to the balanced barrel by the pitching oscillations of the body by way of the drive means, is eliminated or greatly reduced.

In one embodiment a slipping brake system, such as an electrically influenced eddy current coupling is used for fine aim adjustment, while the large moments of aim adjustment are effected, for instance, through a mechanical disc brake of frictional locking type. Other wear-resistant slipping brake systems, such as hydrodynamic retarders and clutches may be used as well. In a practical embodiment of a vehicle brake system, including a hydrodynamic retarder, powers of several thousand HP can be transmitted so that the necessary aiming performance readily can be achieved.

Another advantage results from the use of infinitely variabie eddy current couplings which can be controiled, for example by thyristors, with such accuracy that constantly effective torques act to equalize imbalances in the weapon. The same accurate control is given also with variablefilling hydrodynamic couplings and retarders by virtue of a combined filling and pressure regulation.

To have corresponding adjustment members for both directions of rotation, these members may be driven from the body by a drive means acting through appropriate distributor gearing.

Short reaction times are obtained if two brake systems, respectively for opposite directions of rotation, are used in opposition to each other and quick control is established by reducing the torque of the one brake or increasing that of the other so as to vary the resultant torque.

As the invention provides for improved decoupling of the weapon from movements of the vehicle body, and very high torques and power can be transmitted to the weapon, and also imbalances about the trunnion axis can be compensated by this system, the subject matter of the invention is also excellently suited as the drive system of a weapon to follow up a stabilized observation means. Adjustment signals are applied to the control units of the aiming members (clutches) upon (computer) comparison of the line of sight with the axis of the weapon, e.g. gun bore, in space. As soon as these lines fail to extend in parallel, pulses are applied to the control units of the fine aiming members which then cause followup of the weapon until the angular error has diminished to zero which means that the line of sight and the weapon axis, e.g. the bore axis of the barrel, again extend in parallel.

Also the correction angles determined by a computer and resulting, for instance, for superelevation or canting of the barrel may be allowed for during ballistic shots.

The drive system according to the invention is not limited to stabilizing weapon assemblies on vehicles. It can also be employed for effective stabilization of any masses on movable platforms of any kind.

The invention may be carried into practice in various ways, but certain specific embodiments will be described in greater detail below, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic overall view of an assembly embodying the invention, including a motor drive; Figures 2 to 4 show diagrammatically different forms of clutches for use in the assembly shown in Figure 1, and Figure 5 is a diagrammatic overall view of another assembly embodying the invention, and including a flywheel drive.

Figure 1 shows an example of a tubular weapon drive to illustrate the structure and function of the decoupled drive, i.e. a drive which is free of any disturbing outside moments. The centre of gravity of the weapon 1 lies on the bearing axis, namely the trunnion axis 2. Small deviations between the transverse axis through the centre of gravity and the trunnion axis are permissible. The two aiming drives are located on the trunnion axis 2. However, this arrangement is not an absolute condition, instead it depends on local circumstances. One aiming drive is provided for upward aiming adjustment and one for downward aiming adjustment. Each of the corresponding drive transmissions includes an adjustment means for coarse aiming 3 and an adjustment means for fine aiming 4.The two drive transmissions are driven by way of respective gear trains 5 and 6, both being driven at the same angle speed, yet in opposite sense from a main drive shaft 7 through a bevel gearing 8. The main shaft 7 in turn may be driven by any driven means 9, e.g. a traction motor or a flywheel energy storage means. The slipping of the adjustment member for fine aiming 4 permits variations of the number of revolutions per minute within certain limits. It is the task of the adjustment members for fine airning 4 to keep the weapon axis, e.g. the bore axis of the barrel following up the line of sight. Internal and external ballastic correction factors readily can be taken into consideration. The follow-up movements may result from the motion of the target or from motion of the device itself.

The aiming adjustment members 3 for fine adjustment comprise slip couplings of suitable form capabie of transmitting variable torques from their inputs to their outputs. For example continuously-slipping adjustable friction clutches may be used as the members 3 and 4 whose torque transmission may be fully controlled.

The adjustment members 4 for course aiming also comprise adjustable couplings, but not necessarily of the continuously-slipping kind. If necessary they may comprise couplings, e.g.

mechanical friction clutches which can be engaged solidly to transmit torque without slip, and can be disengaged.

If necessary, the adjustment members for coarse aiming 3 each may be coupled rigidly with the drive means 9 by a mechanical clutch of friction-lock type adapted to be engaged and disengaged. In this manner high aiming speeds can be realized, such as are required for rapid target tracking or during automatic loading of the weapons. The high performances which are thus required briefly, can be made available either by the traction motor drive means 9 or by the flywheel energy storage means 9.

Various solutions can be devised for technically realizing the fine and coarse aiming by elevation adjustment members comprising slip clutches and couplings. Figures 2 to 4 show three different embodiments.

According to Figure 2 each adjustment member 4 for fine aiming is constituted-by an eddy current coupling. The coupling torque is controllable, for example, by means of thyristor control with very little lost motion and aiming time in response to the particular requirement. Pitching oscillations of the vehicle about a transverse axis parallel to the trunnion axis have no disturbing influence on the weapon 1 which must follow up, since the torque/speed characteristics are flat in a certain range of the speed of revolution for a predetermined excitation.

According to Figure-3 the adjustment member for fine aiming is constituted by a hydrodynamic clutch. The magnitude of the torque transmitted by the clutch (entrainment torque) is controllable, as required, with very little lost motion and short adjustment time by means of combined pressure and filling regulation of the clutch. Here again, the characteristics of the hydrodynamic clutch are such that pitching oscillations have no disturbing influence on the weapon which must follow up.

According to Figure 4 the adjustment member 4 for fine aiming is a hydrodynamic retarder in combination with a planetary gearing whose sun wheel is coupled to the rotor of the retarder and whose planet carrier is driven by the gearing 5, the ring gear being connected to the shaft 2. With this arrangement, too, combined pressure and filling control provides the necessary entrainment torques with very little lost motion and short aiming time. The characteristics thus adjustable of the hydrodynamic retarder eliminate any disturbing influence of the pitching oscillations on the weapon which must follow up. The power distributing planetary gearing permits a torque increase of the following-up weapon, free of any moment of reaction.The adjustment signals are applied to the control units of the aiming elements 3 and 4 by means of an eledtronic computer, for example, which processes all the measuring values and factors of influence.

Figure 5 shows a embodiment of the drive means including a flywheel storage means. In this case energy is transmitted to the weapon 1 which must follow up, by two flywheels 10 disposed on the trunnion axis 2 and thus decoupled from the vehicle body about their axes of rotation. With this arrangement, a flywheel each is required for upward and downward aiming. However, arrangements are also conceivable which require but one flywheel for upward and downward aiming. The two flywheels 10 are accelerated to the operating speed by intermittent operation of a feed motor 1 the rotor 1 2 of which is likewise decoupled from the body about its axis of rotation.

A gear train 13 is needed in the embodiment comprising but one drive means to drive the second flywheel in the opposite direction of rotation to the first. Structural units as described with reference to Figures 2, 3 and 4 may be used as clutch members. As an alternative a double motor drive may be provided including a second drive means 14 (shown in discontinuous lines) and eliminating the gear train 13.

The lost motion and adjustment time may be reduced by operating the two adjustment members 4 for "upwardly" or "downwardly" fine aiming (Figs. 2 to 5) simultaneously in opposition to one another. Minor disturbing moments resulting from air forces, or imbalances, such as produced by different weights of the ammunition and under the influence of foreign bodies on the weapon, can be compensated constantly by the adjustment member for fine aiming in upward or downward direction, in response to the sign, without impairing the accuracy of the foilow-up.

Claims (6)

1. Apparatus for aiming a weapon mounted on a mobile carrier, for example a vehicle, based on eliminating the influence of travelling motions of the vehicle on the aiming procedure, the weapon being supported at its centre of gravity in a manner substantially free of bearing forces, which apparatus comprises a high-speed power drive means mounted on the carrier and an adjustable rotary coupling, for example a continuouslyslipping clutch, interposed in a drive transmission between the high speed drive means and the weapon to transmit to the latter and aim-adjusting torque independent of the speed of rotation of the drive means in the high speed range about at least one aiming axis, together with an additional solidly-engageable and releasable friction clutch disposed in the same or an additional drive transmission to transmit high torques to the weapon for rapid follow-up or aiming movements (coarse aiming).

2. Apparatus as claimed in Claim 1 in which the drive transmission includes a power-distributing gear mechanism having three available shaft ends, one of which is driven by the power drive means, the second of which is connected to the rotary coupling, and third of which is connected to the weapon.

3. Apparatus as claimed in Claim 1 or Claim 2, in which, for avoidance of reversal of the power drive means when a change in the direction of aim adjustment is required, and for reducing lost motion and clearance, two of the rotary couplings are provided whose inputs are driven in opposite directions at the same angular speed by the same power drive means through transmission means and acts on the weapon about the same aimadjusting axis.

4. Apparatus as claimed in any one of Claims 1 to 3, in which for the purpose of compensating for any imbalance or other moments of disturbance, a stabiliser system is provided for a sighting means for the weapon, and includes a stabiliser gyroscope which applies an output signal to a control means for the rotary coupling to adjust a compensating entrainment moment imposed on the weapon.

5. Apparatus for aiming a weapon, mounted on a mobile carrier, for example a vehicle, based on eliminating the influence of travelling motions of the vehicle on the aiming procedure, the weapon being supported at its centre of gravity in a manner substantially free of bearing forces, which apparatus comprises a flywheel mounted for rapid rotation about the trunnion axis of the weapon and driven by a driving means mounted on the carrier with means for disconnecting the drive means from the flywheel after acceleration of the latter to an operating speed, there being at least one coupling element interposed in a drive transmission between the flywheel and the weapon for transmitting an aim-adjusting moment to the weapon about at least one axis.

6. Apparatus for aiming a weapon mounted on a mobile vehicle or other mobile carrier, substantially as specifically described herein with reference to Figure 1 of the accompanying drawings along or in combination with any one of Figures 2 to 4, or to Figure 5.