US 3336872 A
Description (OCR text may contain errors)
Aug. 22, 1967 E. w. LANGEN ET AL 3,336,872-
FUZE WINDOW ASSEMBLY Filed Aug. 12. 1965 [in 31w:
INVENTORS EDWARD w. LANGEN RAYMONDF. LIMOGES ATTORNEY 3,336,872 FUZE WINDOW ASSEMBLY Edward W. Langen and Raymond F. Limoges, Rochester,
N.Y., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Filed Aug. 12, 1965, Ser. No. 479,356 7 Claims. (Cl. 10270.2)
ABSTRACT OF THE DISCLOSURE A shield for a critical surface area of a projectile or missile normally exposed to contaminants during launch comprising a low melting point metal layer which is hard enough to resist surface damage during storage but readily melts due to temperature rise during flight and is then cast off. It is particularly applicable to infra-red fuze windows.
The present invention relates to projectile fuzes and more particularly to a novel shield for the protection of critical surface area such as the infrared windows commonly used in variable time fuzes.
Heretofore difliculty has been experienced in protecting windows used in the fuzes of certain projectiles or missiles to prevent blinding thereof by deposits from the propellant gases to which the window is exposed during projectile or missile launch. It will be apparent that the existence of such deposits can interfere with or completely prevent the proper actuation of the fuze by rays trans mitted through the window and hence some means must be provided for preventing the deposit of propellant material thereon or for removing such material once it has been deposited.
It has been proposed that a coating of wax or similar material could be applied over the window which wax mixture would melt at the stagnation temperature developed during the missile flight. The wax however, though effective when carefully applied and when not damaged during projectile handling, has proved to be not suitable for production purposes.
Briefly the present invention provides window protection by positioning thereover a thin shield of a suitable metal which shield when exposed to the very substantial temperatures developed during weapon flight will melt and be wiped or thrown from its position in front of the window assembly, aided by centrifugal spin forces.
An object of the present invention is to provide a device and method for protecting critical areas such as the ray transmitting windows of weapons against contamination during weapon storage or handling or from the propellant gases developed during weapon launching.
Another object is to provide a simple, light and inexpensive projectile window shield which is cheap, easy to apply and uniformly effective in operation.
Another object is to provide a protective shielding device which may readily be applied during the normal window assembly process with a minimum interruption or interference with established assembly line procedures.
Still another object is to provide a window assembly protecting device which remains fixed in place during weapon storage and handling and during weapon launch but which is automatically removed by the normal environmental conditions encountered after launch.
Other objects, advantages, and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein:
FIG. 1 is a vertical elevation partially in section of the forward tip of a projectile nose fuze illustrating one embodiment of the present invention;
} United States Patent 3,336,872 Patented Aug. 22, 1967 stainless steel, upon which is received a protective cover or shield in the form of a disk 17. Above all rests a retaining ring 18 which may be held in place by an overturned flange portion 19 of the casing;
In the embodiment illustrated the inner surface of housing 10 is shown provided with a second ledge 20 upon which rests the outer edge of the thin flat stainless steel washer 16. This ledge protects the window assembly 12 from too much compressive force when the entire assembly is compressed together and provides a solid abutment to receive the pressure which is applied to crimp over the flange 19.
The protective shield or disk 17 is formed of a metal alloy which has a melting point of 203 F. and the com position of which is 52.5% bismuth 32.0% lead and 15.0% tin. A shield thickness of .0015 inch has been found preferable in the embodiment illustrated.
It will be apparent that the shield of this material will protect the window assembly from contamination during storage and handling and during the initial weapon launch when it is most likely to be contaminated by propellant gases. Thereafter during the mid flight of the weapon the thin shield is rapidly heated by the air through which it passes to attain a temperature in excess of its 203 F. melting point. At such temperature the thin disk quickly disintegrates and spins to the outside of the window assembly and is dissipated from the important ray transmitting surface thereof.
It will be obvious that there are several advantages to the construction illustrated, particularly when the fuzes are being assembled by automatic or semi-automatic machinery and it is a fairly simple matter to add the stainless steel washer and the protective metal disk before the retaining ring is secured in place.
Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
1. In a fuze construction for an aerial weapon wherein a critical surface area must be protected from contamination by propellant gases developed during weapon launch the combination of:
a casing having a ledge for supporting a member with a critical surface;
a critical surface member supported on said ledge;
cushioning pads on opposite sides of the critical surface member;
said pads being disposed about the periphery of said critical surface member so as to leave the central area unobstructed; and
a protective shield of fusible material positioned over said critical surface said shield being fusible at temperatures normally generated by weapon flight.
2. The fuze construction of claim 1 wherein the parts are circular in form.
3. The fuze construction of claim 1 wherein a load distribution washer having an open area is located between the protective shield and the critical area.
4. The fuze construction of claim 1 wherein the protective shield is formed of an alloy of bismuth, lead and tin.
5. The fuze construction of claim 1 wherein the protective shield is formed of an alloy of bismuth 52.5%, lead 32.0% and tin 15.5%.
6. The fuze construction of claim 1 wherein the protective shield is approximately .0015" thick.
7. A fuze for an aerial Weapon comprising:
a casing having a central opening, said opening being bounded by an inwardly projecting ledge;
a critical surface assembly including a critical surface member located within said opening and resting on said ledge;
a second ledge Within said opening and spaced from the first ledge a distance to accommodate the critical surface assembly;
a flat washer with its outer portion resting on the second ledge and its inner portion projecting inwardly 4 to overhang the periphery of the critical surface assembly; a thin flat shield of metal overlying and protecting said critical surface; said shield having a melting point substantially below the temperature reached by the weapon in flight; and a retaining ring having an open central area and serving to retain the parts in close relationship.
References Cited UNITED STATES PATENTS 3,026,805 3/1962 Becker 10270.2 3,065,930 11/1962 Edelman 244-3.16 3,080,817 3/1963 Robinson et a1. 102-925 3,113,521 12/1963 Waller 10292.5
BENJAMIN A. BORCHELT, Primary Examiner.
SAMUEL FEINBERG, Examiner.
20 W. C. ROCH, Assistant Examiner.