A flip-out mechanism for target trackers

Abstract: The present invention relates to a flip-out mechanism for target trackers (5) for sub-combat units (1) of the type intended to be transported by a carrier body to a target area where it is dropped for scanning the area under braked fall with its target tracker (5) and for combatting targets possibly identified there. The problem solved by the present invention is that of retarding, in a gentle and efficient manner, the flip-out of the target tracker (5) and thereafter of locking it in the flipped-out position.

Description: TECHNICAL FIELD The present invention relates to a flip-out mechanism for target trackers for such sub-combat units, provided with their own target trackers and triggering sensors, as a carrier body or vehicle in the form of a shell or missile transported to a predetermined target area in order there to be discharged from the vehicle and, while the sub-combat unit falls in a spiral trajectory towards the earth, scans the target area with its sensors and combats any possible targets identified there, such as MBTs. The basic principle of the sub-combat unit of the type contemplated here and defined in the preamble of claims 1 and 3 is described in SE-A2-8601423 (=EP-A-0252036). BACKGROUND ART The characterizing feature of the sub-combat unit described in the patent is that it is provided not only with a flip-out target tracker and triggering sensor but also with a similarly flip-out designed carrier surface. In their flip-out positions, the target tracker and carrier surface together provide for the sub-combat unit a suitably balanced retarding area which imparts to the unit its predetermined fall velocity combined with the previously mentioned spiral fall trajectory, which makes it possible for the sensor to scan the pertinent target area for targets to be combatted. SE-A0-8903473-0 (=EP-A-0424336) and SE-A0-9001227-9 (=EP-A-0451123) describe further variations of flip-out carrier surfaces intended for sub-combat units of the type contemplated here. Such carrier surfaces may also consist of parachutes. As will be apparent from the above disclosure and in greater detail from the above-mentioned references, the sub-combat units are provided with a plurality of flip-out parts which, during ejection from the vehicle, must be protected from damage, at the same time as the preplanned scanning of the target area requires that the flip-out of these parts takes place exactly as planned. The flip-out proper of the target tracker implies no specific problems in such cub-combat units as have, at the desired flip-out time, at least a certain inherent rotation. In such an event, the flip-out operation can be left to the rotation forces and, thus, it is sufficient simply to release the target tracker in order to activate the flip-out operation. For example, this may be combined with the sub-combat unit being forced, by a powder charge adapted to this purpose, out of a protective canister in which it was initially discharged from that vehicle which had transported it to the pertinent target area. The rotation which is required in order thereafter to flip out the target tracker need not be particularly powerful. In one specific embodiment, we expect that the target tracker can be reliably flipped out at a rotation of the order of magnitude of 10 revolutions/second. On the other hand, a problem may be experienced in realizing efficient and space-saving means for retarding the flipped-out target tracker in its flipped-out state and in locking the tracker in this position. Sub-combat units are of extremely limited size within which a partly complex electronics system must be accommodated, as well as one or more bulky warheads. The space which is available for means for retarding the target tracker in its flipped-out position and locking it there against further movement is, as a result, limited in the extreme. Moreover, the target tracker (which contains the major proportion of the relevant electronics) must be retarded gently so that neither the electronics nor the anchorage of the target tracker is damaged, at the same time as the target tracker must be locked without any play in its flipped-out position. The object of the present invention is, therefore, to solve the above-outlined problems. SOLUTION This is achieved according to the present invention such that the retardation is effected by means of an initially compressed flexible brake band according to the characterising portion of claims 1 and 3 and which, for example, may be of thin steel and which, during flip-out of the target tracker from its one anchorage point in the proximity of that point on the target tracker which, on flip-out, moves the greatest distance, is stretched past an elastically deformable damper body secured in the main portion of the sub-combat unit and optionally consisting, for example, of rubber or other polymer material with suitable properties. In such instance, the damper body is disposed in relation to the stretching of the brake band such that it will, at least in the final phase of the flipping-out of the target tracker, be deformed which gives a resilient retardation of the flip-out movement of the target tracker. An extension of the brake band which has proved to be suitable is to secure it to one side of the damper body and cause it to extend in an arc around at least a part of the damper body before it extends further towards the first anchorage point in the target tracker. A design which has proved to be advantageous comprises, on the one hand, the above-described retarder arrangement and, on the other hand, a return stop which is activated in such a manner that, in the final position, a certain pretensioning in the brake band will be obtained. This is realized by adapting the different parts such that the target tracker is first flipped out to a maximum position which is slightly further out than the desired end position and, at the same time, a return stop which may consist of a simple leaf spring is allowed to yield, whereafter a portion of the elastic deformation of the damper device is caused to retract the target tracker until the return stop is activated. By retaining, in this final position, a part of the deformation of the damper body, a pretensioning of the brake band will be obtained and an efficient locking of the target tracker in the flipped-out position. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The method and the apparatus according to the present invention are 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 shows a sub-combat unit of the type contemplated here under retarded fall; Fig. 2 shows the upper portion of the same sub-combat unit seen from above (the flip-out carrier surfaces which are not germane to the present invention have not, however, been included); and Fig. 3 is a section through the upper portion of the sub-combat unit as illustrated in Fig. 2. DESCRIPTION OF PREFERRED EMBODIMENT Fig. 1 shows a sub-combat unit 1 during retarded fall. Its main portion consists of a warhead charge 2, but it is also provided with two flip-out carrier surfaces 3 and 4 and the flip-out target tracker 5 relevant to this context. Fig. 1 shows all flip-out devices in the flip-out position. It will be apparent from Fig. 2, which thus shows the sub-combat unit seen from above, that the flip-out target tracker 5 (which is flipped out in the figure) is pivotally journalled about a pin 6, and that the sub-combat unit has a superjacent carrier beam 7 against which a return stop 8 disposed on the target tracker has been raised to start position in order thereby to prevent the target tracker 5 from returning to the starting position. The return stop 8 consists, in this specific case, of a simple leaf spring which yields and constitutes an efficient stop as soon as it has passed out beneath the carrier beam 7. The retarder device, which principally characterizes the present invention and is most readily apparent from Fig. 3, consists of the brake band 9 which is secured in the target tracker 5 at a first anchorage point 10. Thence, the brake band 9 runs in an arc about a damper device 11 to the second anchorage point 12 on the other side of the damper device. This in turn consists of an elastically deformable rubber stud. In the initial phase, the target tracker 5 is retracted and the brake band 9 folded in inside the target tracker. The return stop 8 in turn is clamped in beneath the carrier beam 7. When the target tracker is flipped out by the rotational force or by other means, the brake band 9 will first be stretched and thereafter at least partly deform the damper device 11. In such instance, a gentle retardation of the flipping-out of the target tracker will be obtained. Given the correctly adapted properties of the damper device 11, the target tracker will be flipped out a slight distance further than to its intended final position. In this instance, the return stop is given the opportunity to yield, whereafter the elasticity of the damper device comes into play and attempts to reassume its original form, the brake band being retracted by the target tracker so that the return stop 8 abuts against the carrier beam 7 and is retained in this position by a certain residual deformation of the damper device, this providing a pretensioning which prevents any further movement on the part of the target tracker.

Claims: In the flip-out of a flip-out target tracker (5) on a sub-combat unit (1) of the type which is transported by a carrier body or vehicle such as a shell or a missile to a predetermined target area in order there to be activated during flip-out of the target tracker (5) for scanning the target area therewith during its braked fall for identifying targets and combatting the same by means of an integrated warhead (2), a method of retarding the movement of the target tracker (5) during the final part of its flip-out phase without its contents or journalling (6) being damaged characterized in that the retardation is effected with an initially folded, flexible brake band (9) which, during release from its one anchorage point (10) in the proximity of that portion of the target tracker (5) which, during flip-out, moves the longest distance, is stretched past an elastically deformable damper body (11) secured in the main portion of the sub-combat unit, and which is caused, by the brake band (9) during the final stage of the flip-out phase, to be at least partly deformed so that it is stretched between said first anchorage point (10) and a second anchorage point (12) in the main portion of the sub-combat unit (1) on the other side of the damper body (11) compared with that point on the damper body (11) where the body and the brake band (9) first meet. The method as claimed in Claim 1, characterized in that the elastically deformable properties of the damper body (11) are selected such that the body initially permits the target tracker (5) to be flipped out to a maximum position somewhat further out than its intended final position, and the target tracker (5) is thereafter influenced such that it is retracted to a stop position against a stop member (8) activated during the flip-out to maximum position. A retarder device for use in accordance with the method as claimed in Claims 1 and 2 for braking, in a predetermined flip-out position, a flip-out target tracker (5) of the type which is included in such sub-combat units (1) as are transported by a carrier body or vehicle to a predetermined target area over which the sub-combat unit is dropped in order there to scan, with its target tracker (5) during braked fall, the target area and combat any possible identified targets in the area by means of an integral warhead (2), characterized in that it includes a flexible brake band (9) which has a first anchorage point (10) in the target tracker in the proximity of that point thereon which, on flip-out, travels the furthest distance, and a second anchorage point (12) in the main part of the sub-combat unit, and the brake band (9) extending, when the target tracker (5) is wholly flipped out in the tensioned position, from the first (10) to the second (12) anchorage points, and passes an elastically deformable damper body (11) preferably secured in the main part of the sub-combat unit, the damper body being at least slightly deformed when the target tracker (5) is flipped out. The retarder device as claimed in Claim 3, characterized in that the brake band (9) runs in an arc from its second anchorage point (12) which lies on one side of the damper body (11) about the end wall side of the damper body and along its opposing side to the first anchorage point (10). The retarder device as claimed in Claim 3 or 4, characterized in that there is also included a resilient return stop (8) which is operative, when the target tracker (5) has been flipped out to a maximum position, to yield in order, when the damper body resiliently returns, to arrest the return movement of the target tracker (5), said damper device (11) being adapted such that a certain pretensioning of the latter and thereby also of the brake band (9) remains. The retarder device as claimed in any one of Claims 3-5, characterized in that the brake band (9) is of steel and the damper device (11) of rubber or other polymer of suitable properties. The retarder device as claimed in Claim 5, characterized in that the return stop (8) consists of a yieldable leaf spring.

Inventors: VESA REIJO, VESA, REIJO
Applicants: BOFORS AB
Application year: 1992
Main classification: F42B10
IPC codes: F42B30