US 3279405 A
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Description (OCR text may contain errors)
Oct 18, 1966 A. K. BILLMl-:YER 3,279,405
TORPEDO NOSE CAP RETAINING DEVICE Filed March 29, 1965 INVENTO ALLEN K. BILLME R BY V. C. M ER ORNEY.
lto Howard, 2,889,772, discloses such type of device.
United States Patent O 3 279 405 ToRPEDo NosE CAP RETAINING DEVICE Allen K. Billmeyer, Covina, Calif., assignor to the United States of America as represented by the Secretary of the Navy Filed Mar. 29, 1965, Ser. No. 443,721 2 Claims. (Cl. 114-20) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes Without the payment of any royalties thereon or therefor.
This invention relates to protective nose caps for missiles, such as torpedoes, which are dropped into water, and more particularly to novel apparatus for securing such nose caps to missiles.
It has long been common practice to launch homing torpedoes from aircraft or by rocket motor, the torpedo being limited in speed during its descent by a parachute which detaches upon water entry. The sonic transducer on the forward end of the torpedo 1requires protection against the severe water entry shock and one of the devices iirst employed for this purpose comprises :a mass of frangible material, such as foamed material, which is secured to the torpedo ahead of the transducer, which upon water entry, shatters into fragments. The patent The manner of securement of such device to the torpedo was not considered optimum, however, and as it was developed into superseding versions the mass of material was disposed Within a frangible plastic shell which telescoped over and fricti-onally engaged the outer surface of the torpedo hull. While this shell-type nose cap could be rapidly attached to or detached from the torpedo, since it required no specialized fastening means, it suffered the disadvantage of dimensional instability resulting from temperature and humidity changes of aging effects. Thus, if the plastic shell expanded beyond maximum tolerance it would lit the torpedo loosely and be subject to unauthorized dislodgement.
One of the objects of the invention is to provide apparatus for securing a frangible dimensionally unstable nose cap to the nose of a torpedo.
Another object is to provide apparatus of such type which may be retrotted to existing nose caps which would Iotherwise be unserviceable for use.
A further object is to provide apparatus of such type which will secure a n-ose cap to a torpedo with a substantially constant frictional force irrespective of dimensional changes of the nose cap.
Still further objects, advantages and salient features will become more apparent from the description to follow, the appended claims and the accompanying drawing, in which:
FIG. 1 is a side elevation of an air dropped torpedo about to enter the sea;
FIG. 2 is a side elevation of the forward end of the torpedo, portions being shown in section;
FIG. 3 is 4an enlarged section taken on line 3--3, FIG. 2;
FIG. 4 is :a section taken on line 4-4, FIG. 3; and
FIG. 4A is alike section, but with the nose cap removed from the torpedo.
Referring now to the drawing, and iirst to FIG. l, torpedo is of Vconventional construction, having propellers 12 at its rear end and a plastic nose cap at its forward end, which, upon water entry, disintegrates, air stabilizing parachute 16 simultaneously being released from the torpedo. As shown in FIG. 2, nose cap 14 comprises :a thin plastic shell 17, formed in the shape of a curve of revolution, the forward end of which is filled with foamed material 18 which protects thetransducer 20 from damage upon water entry and which also d-isintegrates upon water entry, all as well understood in the art. Since the fragments of the shell and foam material are forced rearwardly along the torpedo and into the path of the propellers it is essential that no parts of the nose cap be of metal which might damage ythe sharp edged precision machined propel- 1ers.
As shown in FIG. 3, the shell is provided with a plurality of angularly spaced longitudinally extending ribs 22, the inner diameter of which are slightly less than the outer diameter of the torpedo so that when the nose cap is forced onto the torpedo, sometimes prior to launching, it frictionally engages the torpedo with suflicient force to remain aixed to the torpedo until the latter enters the water. It -s now apparent that -if the nose cap increases in diameter beyond allowed tolerance due to growth of the material by ageing or temperature and humidity expansion it will no longer frictionally engage the torpedo with the desired force, thus rendering the nose cap useless for its intended purpose. It is also now apparent that if some further securing means could be applied to the nose cap which would friction-ally engage the torpedo with the desired force, irrespective of dimensional change of the nose cap, not only could nose caps which had become useless be salvaged for use but the molding dies and other manufacturing equipment could continue to be used in the future without the necessity of any major redesigns of the nose cap, thus effecting savings in cost.
In solving the foregoing problems certain fundamental requirements were recognized. Anything added to the nose cap should be non-metallic to avoid injury to the propellers. Frictional engagement was still desired because of the ease of manually applying the nose cap without tools or fasteners of any sort. Further, no hole-s or projections could be tolerated on the torpedo nose nor could any materials be employed which would scratch the highly polished surface of the torpedo. Lastly, if frictional engagement were to be employed, the space in which attachment securing means could be disposed was small, being limited to clearance spaces 24, bounded by ribs 22, t-he outer diameter of the torpedo, and the inner diameter of the shell. Based upon the requirements referred to and the limitations of space, the solution to the problem led to experiments with many shapes of non-metallic springs which conceivably would solve the problem but which resulted in either failures or only partial solutions. The spring which was iinally discovered to provide a complete solution and which forms the subject of the invention Will now be described.
Referring now t-o FIGS. 3, 4 and 4A, spring 26 is of the at type, composed of liber glass which is impregnated with epoxy resin, the glass bers all preferably extending in parallel directions longitudinally of the spring as distinguished from woven glass libre material which has both warp and weft libers. In its manufacture, the fibers are laid across a suitably shaped form, impregnated and then cured. Alternatively, pre-impregnated glass libre may be disposed between a pair of shap'ed dies and cured. As best shown in FIG. 4, one end of the spring is cemented to the inner surface of shell 16 adjacent its rear edge, its other end being free to slide, as it is compressed, along the inner ,surface of the shell, the cent-ral portion being bowed, as shown. It is vthus `a bowed beam with a ixed Iabutment at one end and a slideable abutment at `the other. When the nose cap is forced longitudinally onto the torpedo nose from the position of FIG. 4A, the springs fiat- -ten to the position shown in FIG. 4, the central portion of the bowed beam applying the spring force to fthe torpedo.
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.
What is claimed is:
1. In a torpedo having a cylindrical nose section, formed of a material subject to relatively low dimensional change resulting from Vtemperature change, said nose section having a transducer .at the forward end, an ogival plastic hollow nose cap having the rear edge telescopically disposed around the nose section, the front end -of the nose cap containing la frangible foam material adapted to fragment and protect .the transducer upon water entry im# pact, said nose cap being of plastic material subject to relatively high dimensional change Iresulting from temperature and humidity changes or growth by ageing effects, the improvements in combination, comprising;
(a) a plurality of angularly spaced elongated fibre glass springs, fabricated from flat material disposed parallel to the axis of the torpedo, for `secu-ring the nosel cap to the nose section, g
(b) each spring having one end bonded to the nose cap,
such as by cementi-ng,
(c) the other end abutting .and being free to slideably move relative to the nose cap,
(d) an intermediate portion being bowed to arcuate shape and engaging the nose section, whereby the intermediate portion frictionally engages the nose section with suflicient force to retain the nose cap thereon irrespective of large dimensional changes of the nose cap.
2. Apparatus in accordance with claim 1 wherein said one end of each spring is bonded to the nose cap adjacent its rear edge.
References Cited by the Applicant UNITED STATES PATENTS 2,172,086 9/ 1939 Marsfalski. 2,475,608 7/ 1949 Gasparich. 2,637,440 5 195 3 Lodewick et al. 2,637,462 5/ 1953 Becker. 2,841,307 7/ 1958 Yoder. 2,912,769 11/ 1959 Kruger.
20 BENJAMIN A. BORCHELT, Primary Examiner.
S. W. ENGL-E, Assistant Examiner.