US2197841A - Shell or bomb - Google Patents

Description

April 23, 1940. c HTER 2,197,841

SHELL OR BOMB Filed Jan. 4, 1956 2 Sheets-Sheet 1 INVENTOR April 23, 1940. c. E. SLAUGHTER SHELL on BOMB Fiied Jan. 4, 1936 2 Sheets-Sheet 2 IDINVENTOR Patented pr. 9 ll i if l ii) SHELL OR ISO 5131 tion of New Jersey Application January 4, 1936, Serial No. 57,559

4 Claims.

This invention relates to a shell or bomb of the generally cylindrical type having metallic walls enclosing 'an explosive charge and carrying as a tip a fuse device molded from a plastic material comprising a resin binder such as a phenol-formaldehyde resin incorporated with a fibrous material giving the composition adequate strength.

A number of plastic compositions fail to fulfill the requirements of water resistance and strength necessary to be used to form the parts of a fuse tip in projectile manufacture. The phenolformaldehyde resins or similar phenolic aldehydic condensation products are, however, sufiiciently water resistant that they do not change in shape or volume on exposure to humid or dry conditions. The phenolic resins, nevertheless, are not ordinarily of suflicient strength when prepared with the aid of the usual wood flour filler to withstand the tremendous centrifugal force resulting from the firing of certain types of shells. On the other hand, there are certain types of projectiles, such as airplane bombs, which are not subjected to certifugal action during propulsion and these, therefore, require a fuse tip of only moderate strength but which does not expand or contract objectionably under variations in weather conditions.

In the present invention I therefore contemplate the use of two types of fuse tips, one of which is free from any metal reinforcing while the other tip has a reinforcing metallic skeleton into and about which the plastic material is pressed and hardened to final form.

As the phenol-formaldehyde resins are best suited for the purpose in view of their water' resistance and for other reasons, I desire to have them constitute the preferred embodiment of the present invention. As noted above, wood flour, the usual filler with a phenol-formaldehyde resin, is not strong enough for many purposes and, where high strength is necessary preferably I employ a plastic composition of the phenol-formaldehyde type containing as a filler canvas or canvas fiber, but it should be understood that I do not wish to limit myself thereto but may use type also made from a molded composition. Fig. 5 represents in elevation a metal-reinforced type of fuse. Fig. 6 shows a horizontal section on the line H of Fig. 5, diagrammatically shown in section, a metal-reinforcing structure. Like ref-' erence numerals denote like parts in the several drawings.

In Fig. 1 the wall of the shell is denoted by I,- having the driving ring 2 and fuse or fuse head 3. As now produced these are ordinarily carefully machine out of metal suitable for the purpose.

Fig. 2, being of the armor-piecing type, has a tip or nose of steel, the fuse being placed in the base of this type of shell. The base of the shell is designated by d, carrying the fuse and arrangement 5 shown in a diagrammatical way.

Fig. 3 is the fuse or fuse tip made of molded plastic material as aforesaid having the threaded portion 6 which screws into the upper portion of the shell structure, Fig, l. i is a band used for adjusting the time of detonation or explosion and this band is ordinarily called a time ring. The fuse is also provided with a safety device, such as the safety pin 8.

Fig. 4 has in place of the time band or time ring the band portion 9 arranged with weights which fall off by centrifugal force, thus actuating or causing to be actuated the detonating charge, when pin it is sheared, on contact of the fuse with any object. The internal arrangement of the illustrative fuse of Fig. 4 is indicated ,by the dotted lines IO, M and I2.

Since a. shell in order to travel in rectilinear flight must be rotating at high speed the centrifugal force of such rotation sometimes is very high, exerting a pressure on the plastic material which would be sufficient to rupture the bonding 'thereof. 'In such cases a metallic reinforcin such as is shown diagrammatically in Fig. 5 which may be tapered, as shown at l9, extends into the body of the fuse and carries projections adequate to preserve or create a high degree of strength in the molded portion. A cross sectional view of the screw threaded hollow stem extending into the shank or threaded portion of the fuse is shown more in detail in Fig. 6.

It is, of course, understood that the illustrations are diagrammatic and that various forms of fuses or fuse heads with many variations inreinforcing metal structures when so used may be suitably employed according to conditions.

An example of a fuse of the type indicated is the following: A phenol-formaldehyde resin of the thermosetting type is impregnated into a filler of desiccated canvas material, the proportion of resin to the canvas fibers being approxi-- mately equal parts. To mold this a minimum molding pressure of 3000 pounds per square inch is applied but ordinarily higher pressures are used, frequently of 4500 pounds or higher. The strength of the molded product tends to vary to some extent with the degree of pressure applied in the hot press and when projectiles are given a very high degree of rotation an enormous centrifugal force results. When such high centrifual force is to be encountered or counteracted I prefer to mold at pressures at 5000 pounds per square inch or even higher. The composition is molded as a solid mass or preferably an insert such as is shown in Figs. 5 and 6 is employed as a reinforcing agent, the ramifications or projections of which form an anchoring mass for the phenolic resin molding composition which when hardened by heat-treatment and the high pressure applied becomes strong enough to resist the rupturing effect of centrifugal force during the flight of the projectile. Thus there is obtained a shell carrying a fuse of hardened plastic material having a metal reinforcement and particularly one which has been formed by hot-pressing at a pressure to give adequate strength for withstanding the centrifugal force developed by the shell in flight. It' may be noted also that hotpressing is preferably carried out at temperatures ranging from 150 C. and upwards to a temperature where weakening of the canvas fiber results, it being an object of the invention to secure maximum strength in the plastic composition and at the same time to obtain a high degree of flow which will cause the plastic composition to move into all parts of the areas about the arms or other projections of the reinforcement to embed such reinforcement securely in the said plastic.

On the bomb time ring I of Fig. 3 a mica asbestos phenolic molded ring may be usedin those cases where resistance to temperature must be eifectuated. The burning of the time fuse generates a considerable amount of local heat which would tend to destroy a composition made, for example, with a wood flour filler plastic. On the other hand, the knob-or tip such as is shown in Fig. 4 above the ring 9 may, if desired, be molded from ordinary wood flour and, for example, phenolic resin or other plastic material as at that point strength is not particularly important. A fuse of this type offers many advantages from the standpoint of rapid production. Ordinarily the mechanism of a fuse made from metal is not only complicated but all parts have to be finely machined, requiring mechanical skilled labor of the highest order. This, in times of military stress when large production may be required, is usually diflicult to obtain. A molded fuse of this type which may be made by mechanical labor that is not of the highly skilled type and which allows of the preparation in advance of a number of molds or dies for the purpose offers the opportunity in the event of military emergencies to produce shells at a very rapid rate.

What I claim is:

1 In an explosive projectile, a fuse of hardened synthetic resin plastic having a metal reinforcement therein, said reinforcement being cruciform in cross section with the ends of the cross arms provided with lateral flanges whereby relative rotation of the fuse and reinforcement is prevented, such plastic body being of sufficient tensile strength to resist the high centrifugal force incident to the normal use of said projectile.

form in cross section with the ends of the cross arms provided with lateral flanges whereby rela tive rotation of the fuse and reinforcement is prevented.

3. In an explosive projectile as set forth, a fuse of canvas-reinforced infusible thermoplastic phenolic resin plastic having a metal reinforcement imbedded therein, said metallic reinforcement being cruciform in cross section with the ends of the cross arms provided with lateral flanges whereby relative rotation of the fuse and reinforcement is prevented and mechanically interlocking the said plastic material thereby preventing relative rotation of one with respect to the other.

4. In combination a fuse having a body of plastic composition, a metallic reinforcement extending axially of said body, said reinforcement being cruciform in cross section with the ends of the cross arms provided with lateral flanges whereby relative rotation of the fuse and reinforcement is prevented, and a threaded extension integral with said reinforcement and extending from the fuse body for engagement with the threaded opening of a shell.

CHARLES E. SLAUGHTER.

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