The present invention relates to a suspension device for connecting an item of on-board equipment to the structure of a vehicle.
Although not exclusively, said suspension device is more particularly intended to be arranged between the structure of a rotary-wing aircraft, particularly a helicopter, and a sighting apparatus of this helicopter, for example an infrared sight.
It is known that helicopter-mounted equipment such as in this preferred application is subjected to significant vibrational phenomena due in particular to the respective main and tail rotors, to their blades, to the transmissions, to the engine, etc., and to variable load factors of the helicopter which are due to its courses and to which said on-board equipment is subjected.
Hence, when the item of equipment is a sighting apparatus mounted on the structure of the helicopter, the impact of these various influences is detrimental to the effectiveness of said sighting apparatus. This often results in a degradation of the stabilization by direct action of the vibration, particularly on the gyroscope and the supports for the optical units, in a degradation in comfort, because the vibration is then transmitted to the images displayed to the sight operator, and in a reduction in the actual reliability of the apparatus, because, for example, the optoelectronic sensors in this sighting apparatus are subjected to constant vibration. What is more, the load factors corresponding to the accelerations of the helicopter also act directly on this equipment.
Document EP-0 588 684 discloses a suspension device capable of overcoming these drawbacks. To this end, that known suspension device comprises:
first and second parts shaped at least approximately in the form of plates and capable of being fixed respectively to said structure and to said sighting apparatus; and
suspension means which are arranged between said first and second parts and which are capable of absorbing, on the one hand, relative linear displacements of said first and second parts along three reference axes in roll, pitch and yaw of said vehicle and, on the other hand, the relative angular excursions of said first and second parts about said three reference axes.
This known suspension device therefore constitutes a xe2x80x9csix axesxe2x80x9d suspension, making it possible to minimize both translational displacements along the three reference axes of the vehicle and angular excursions about these axes, which are produced by the vibrations and the load factors.
In consequence, by virtue of this known suspension device, it is possible to stabilize the sighting apparatus, and this in particular makes it possible to improve the visual comfort of the operator using this sighting apparatus and, above all, to improve the reliability of said apparatus. The line of sight can therefore be stabilized on an observed target and is no longer subjected to the aforementioned displacements and excursions.
However, this stabilizing of the line of sight, which therefore presents an advantage for most envisaged uses (observing the territory, observing and tracking a target, etc.) can, however, become a handicap in certain specific applications, or even not be suited to such applications at all.
Specifically, it may be useful or even necessary, in certain specific applications specified hereinbelow by way of example, to keep the line of sight in a given position with respect to a given reference axis which depends on the helicopter or on a particular item of equipment of said helicopter.
For this type of application, it is therefore necessary, if the operator, particularly the pilot of the helicopter, does not wish to or cannot make his observations with the naked eye, to provide an additional special-purpose sighting apparatus which is fixed appropriately to the structure of the helicopter, this of course increasing the cost and bulk and not being practical, because said operator then has to monitor two different sighting apparatuses.
The present invention relates to a suspension device making it possible to overcome these drawbacks.
To this end, according to the invention, the suspension device for connecting an item of on-board equipment to the structure of a vehicle, particularly a rotary-wing aircraft, said suspension device comprising:
first and second parts shaped at least approximately in the form of plates and capable of being fixed respectively to said structure and to said item of equipment; and
suspension means which are arranged between said first and second parts and which are capable of absorbing, on the one hand, relative linear displacements of said first and second parts along three reference axes in roll, pitch and yaw of said vehicle and, on the other hand, the relative angular excursions of said first and second parts about said three reference axes, is noteworthy in that it additionally comprises:
a controllable locking system capable of bringing said suspension device into one of the following two positions:
a locked position in which said locking system immobilizes said first and second parts one with respect to the other in a given relative position; and
an unlocked position in which said locking system releases said first and second parts to move relative to one another; and
control means for controlling said locking system.
Thus, by virtue of the invention, the suspension device is capable of fulfilling a dual role, namely:
a conventional stabilizing role, such as the one fulfilled, for example, by the suspension device described in the aforementioned document EP-0 588 684, allowing the equipment item to be stabilized with respect to the structure; and
a securing role making it possible, by virtue of the action of the locking system, to secure the equipment item to the structure, respective reference planes of the equipment item and of the structure thus being fixed, for example parallel, one with respect to the other.
In addition, by virtue of said control means, it is possible to switch rapidly from one of said positions (locked position or unlocked position) to the other position. To this end, said control means can be actuated, either manually by an operator or automatically, for example according to the use of another item of equipment of the helicopter which is, for example, used simultaneously with said suspended equipment item.
According to the invention, said locking system comprises at least two, and preferably three, locking means as specified hereinbelow.
In a preferred embodiment, at least one of said locking means comprises:
a first element fixed to one of said first and second parts, facing the other of said parts;
a second element at least partially connected to said other part and capable of collaborating with said first element to obtain a fixed connection between said first and second parts, via said first and second elements; and
a controllable third element capable of bringing said first and second elements into collaboration to obtain said locked position, and capable of separating said first and second elements one from the other to obtain said unlocked position.
In the context of the present invention, said first, second and third elements may be embodied in different ways.
In a first embodiment, said first element comprises a tenon, said second element comprises a centering piece which is fixed to said other part facing said tenon and which comprises a mortise of a shape tailored to said tenon, and said third element comprises a means capable of bringing said two parts closer together in order to bring said tenon into said mortise.
In a second embodiment, said first element comprises a housing, said second element comprises a moving pin which can be guided by a guide fixed to said other part and which is capable of entering said housing which has a shape tailored to said pin, and said third element comprises a means of displacing said moving pin.
It will be noted that, in the latter instance:
in a first alternative form, said locking system comprises two locking means, for one of which the length of the part of the housing capable of accommodating said pin is greater than or equal to twice the diameter of said pin which has a circular cross section; and
in a second alternative form, said locking system comprises three similar locking means, for each of which the length of the part of the housing capable of accommodating said pin is less than twice the diameter of said pin which has a circular cross section.
Furthermore, in a third embodiment of the invention, said first element comprises a sphere, said second element comprises at least two moving parts shaped so as to be able to trap said sphere, and said third element comprises a means capable of displacing said moving parts.
In addition, in a fourth embodiment, said first element comprises a pin which has at least one annular groove on its outer face, said second element comprises an actuatable clamping system comprising at least four spheres capable of trapping said pin by acting in said groove, in a uniformly distributed way around the periphery of said pin, and said third element comprises a means capable of actuating said clamping system.
It will be noted that, in the latter instance:
in a first alternative form, said locking system comprises two similar locking means, for each of which the pin has two annular grooves and the clamping system has eight spheres capable of acting in groups of four spheres in said two grooves respectively; and
in a second alternative form, said locking system comprises three similar locking means, for each of which the pin has just one annular groove and the clamping system has four spheres.
Finally, according to the invention:
in a fifth embodiment, said first element comprises a sphere, said second element comprises an actuatable clamping system capable of trapping said sphere, and said third element comprises a means capable of actuating said clamping system; and
in a sixth embodiment, said first element comprises a part which has a double housing, said second element comprises an actuatable clamping system, the two free ends of said clamp being capable of acting respectively in said double housing, and said third element comprises a means capable of actuating said clamping system.
The present invention also relates to a sighting system for a vehicle, particularly a rotary-wing aircraft, of the type comprising:
a sighting apparatus comprising a sighting means capable of taking images of the external environment of said vehicle and a display means capable of displaying the images taken by said sight means; and
a suspension device allowing said sight means to be connected to the structure of said vehicle.
According to the invention, this sighting system is noteworthy in that said suspension device is a device of the type specified hereinabove, and said sighting system has two different sighting modes:
a stabilized sighting mode, for which said suspension device is brought into the aforementioned unlocked position; and
a fixed sighting mode, for which said suspension device is brought into the aforementioned locked position.
This sighting system therefore has two different and complementing sighting modes. In consequence, there is no need to use two different sighting systems to employ these two sighting modes.
The present invention also relates to a weapon system comprising, in the known way:
a vehicle, particularly a rotary-wing aircraft;
a first weapon unit mounted on said vehicle; and
a sighting system also mounted on said vehicle and capable of taking images of the environment of said vehicle, at least during use of said first weapon unit.
This first weapon unit may, for example, be a known missile-firing system, for example for firing passively guided missiles. To track and/or guide such missiles, it is generally particularly advantageous, or even necessary, to use a stabilized sighting system, especially when the firing vehicle is subjected to numerous and strong vibrations, as is the case, for example, with helicopters.
By contrast, it is known that in the case of other known weapon units, for example gunfire systems or systems for firing various projectiles (shells, bullets, rockets, etc.), if the firing operator uses a sighting system, it is absolutely essential that the line of sight of the latter be locked to, and preferably parallel to, the firing line of said gunfire system (or projectile-firing system).
This is because if the line of sight of the sighting system, instead of being fixed, were stabilized onto a target, the firing line of the gunfire system (which is secured to the structure of the vehicle and therefore subjected to its vibrations) would have a permanent offset from said line of sight (when firing at said target) of angular values which represent said vibrations.
In consequence, if the vehicle is to be equipped with two different weapon units, that is to say ones requiring two different sighting modes, for example the aforementioned weapon units, it is necessary:
either to provide two sighting systems tailored to said different weapon units, which is expensive, bulky and in particular requires two separate display screens, which are hardly practical to monitor;
or to actuate one of the weapon units, for example the gunfire system, without using a sighting system, taking sightings with the naked eye, which is, of course, imprecise and difficult, or even impossible, to achieve, particularly by night or in foggy conditions.
In order to overcome these drawbacks and to allow the use of a single sighting system for two weapon units requiring different sighting modes, for example a missile firing system and a gunfire system, the weapon system of the aforementioned type is noteworthy, according to the invention, in that its sighting system is a sighting system according to the invention, as described hereinabove, and in that it is formed in such a way as to be brought automatically, or following operator actuation:
into said stabilized sighting mode when one of said first and second weapon units is used; and
into said fixed sighting mode when the other of said first and second weapon units is used.
In consequence, by virtue of the invention, a multi-function weapon system is obtained, containing just one sighting system.