Ammunition and explosives – Pyrotechnics – Rocket
Reexamination Certificate
1998-10-13
2001-05-08
Poon, Peter M. (Department: 3643)
Ammunition and explosives
Pyrotechnics
Rocket
C089S001811, C244S121000
Reexamination Certificate
active
06227117
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for retaining an element ejected by a pyrotechnic device when it is triggered. It can be applied especially to the retaining device of the rear igniter of a missile. More generally, it can be applied to any pyrotechnic device with rear ejection of elements such as the igniter, the explosive bolt, the booster, the skids or the lids.
During the phase of the firing of a pyrotechnic device such as the engine of a missile for example, the igniter of the engine is ejected at high speed backwards and has kinetic energy such that the ejection may cause very great harm to human beings and extensive damage to equipment.
2. Description of the Prior Art
To obtain protection from the elements that are thrown out, it may be planned to have a system external to the ammunition known as a system “on the launch pad”. However, a system of this kind has many drawbacks. One example, among others, of drawbacks arises especially out of the fact that the launch pad cannot be too close to the rear of the device. Since they are relatively distant, the elements strike the launch pad with a kinetic energy that is all the greater. Consequently, the launch pad needs to have a sufficiently great mass for more material is needed to absorb the energy. This fact then leads to great complexity in the control servo-mechanisms of the launch pad. Furthermore, the relative distance of the launch pad does not always ensure that the elements thrown out will be captured in a reliable way.
Another approach may for example consist in eliminating the ejection. To prevent rear ejection from a pyrotechnic device, it is possible to ignite its engine from the front. In this case, the pyrotechnic elements are integrated during the assembling of the missile, entailing the risks associated with the handling and the in-plant testing of primed explosive elements.
The positioning of the igniter in the rear of the engine during the final phase of integration minimizes the pyrotechnical risks, especially risks in the plant, but leads to the ejection of the igniter at the firing stage. In addition to the flame effects, the structures located in the rear of the firing line receive, as mentioned here above, the projectiles that are constituted by the ejected elements. Given their high speed, which is greater than 100 m/s, these elements may possess kinetic energy of several hundreds of Joules. These projectiles may therefore cause major damage to neighboring structures or even cause injuries to operators, even if they are shielded, especially owing to the risks of ricochets that are impossible to control.
To prevent the risks associated with pyrotechnic devices of this kind during the firing stage while at the same time keeping the advantages associated with rear firing without using the launch pad to receive the ejected elements, it is necessary to capture these elements by means of a retaining device fixedly joined to the container of the device. In the case of application to a missile for example, the capturing device must in particular correspond to the following requirements:
the pyrotechnic elements should be captured and held captive during the phase of departure of the missile, namely for a time interval of about 0.2 seconds;
the nozzle and the rear of the missile should be released from the missile at high speed, for example within less than 5 ms, to a distance of about 100 mm, but the movement should remain compatible with the templates chosen;
the capturing device should not cause deterioration or disturbances that might lead to a defective launch, and furthermore the retaining forces should be compatible with the capacities of compensation of the servo-mechanisms of the missile-launching turret;
the capturing device should be capable of withstanding the environmental stresses of the ammunition, namely those of the missile and container.
SUMMARY OF THE INVENTION
The aim of the invention is to enable the making of a device that corresponds especially to the above requirements. To this end, an object of the invention is a device for retaining an element ejected by a pyrotechnic device wherein said device comprises at least one metal cap placed behind the nozzle of the device and designed to receive the ejected element, the cap being held in position by curved rigid links, the kinetic energy of the ejected element carrying along the cap and the captured element, the motion of the assembly being braked by the deformation of the rigid links.
The main advantages of the invention are the following: it can be used to obtain a device in the form of a kit that is set so that it is ready to be used, the device can be mounted on a missile during the final integration of the pyrotechnic elements, it can work under very harsh conditions and has very great operating safety, it can be mounted on a missile or any other pyrotechnic device that is already made but has not been fitted out with a retaining system and the making and assembly of the device are economical.
REFERENCES:
patent: 2734425 (1956-02-01), Brandt
patent: 2776623 (1957-01-01), Bonner
patent: 3194119 (1965-07-01), Robert et al.
patent: 3398639 (1968-08-01), Apotheloz
patent: 3674227 (1972-07-01), Jacobson et al.
patent: 3811360 (1974-05-01), Ricks
patent: 4022343 (1977-05-01), Richardson
patent: 4426909 (1984-01-01), Carter
patent: 4522103 (1985-06-01), Mitzner
patent: 4676136 (1987-06-01), Kälin
patent: 5078044 (1992-01-01), Bourgie et al.
patent: 5491917 (1996-02-01), Dilhan et al.
patent: 1254509 (1967-11-01), None
patent: 1.336.054 (1963-12-01), None
patent: 2 685 463 (1993-06-01), None
patent: 996829 (1965-06-01), None
Goillot Paul
Gouthiere André
Koenig Gérard
Peltier Guy
"Thomson-CSF"
Nguyen Son T.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Poon Peter M.
LandOfFree
Retaining device, especially for the rear igniter of a missile does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Retaining device, especially for the rear igniter of a missile, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Retaining device, especially for the rear igniter of a missile will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2505291