US2666389A - Fuze - Google Patents

Description

L. M. COOPER FUZE 2 Sheets-Sheet 1 Filed Nov. '7, 1944 k f W lVW/L Sme/wm man@ m mi k mw NQ Q t mi /`7. COOPER 2 Sheets-Sheet 2 Jan. 19, 1954 l.. M. COOPER FuzE Filed Nov. 7, 1944 Patented Jan. 19, 1954 FUZE Lyle M. Cooper, Rahway, N.

United States of Amerie Secretary of War J., assigner to the a as represented by the Application November 7, 1944, Serial No. 562,370 3 Claims. (Cl. 102-76) The invention described herein may be manufactured and used by or for the Government, for governmental purposes, without 4the payment to me of any royalty thereon.

This invention relates to a combination percussion and time fuze or ring mechanism particularly adapted for use in tail ejection type bombs released from aircraft in clusters.

Tail ejection incendiary bombs were given greater capabilities and became standardized when equipped with fuzes made in accordance with the present invention. up of two principal assemblies, the fuze and the case. The case serves as a container for an incendiary or chemical agent, an ejection charge, and the fuze. The fuze fitted into the case is the means for transforming energy of impact into a controlled ignition for ring the ejection charge.

Among others, objects of the invention are to provide a fuze sufficiently compact to increase the loading efficiency of the bomb, simple for safe handling, easy assembly and manufacture with a minimum of scarce materials, sealed for waterproofness, and constructed for dependable functioning even when the bomb slants at an angle from the vertical on impact with surfaces of various degrees of hardness.

In a preferred form the fuze of the present invention comprises a die cast base formed to hold a primer cap, a weighted striker arm or lever pivotally hinged to the base in such a position that the striker swings through a small arc (less than 45) in functioning, and a torsion spring for holding lthe striker arm normally away from the primer cap. This mechanism is housed within a cylindrical metal shell, such as a steel tubing, secured to the base. The .base has a longitudinal bore for insertion of a suitable time delay powder train element, such as a lead spitter fuse, leading from the bottom of the primer cap to the rear end of the base, to which is attached a booster or rst re charge in a cellulose nitrate plastic cup. The head of the base is provided with an aperture for insertion of a safety plunger generally in a central position and disposed in relation to the mechanism so that the plunger in an unarmed position prevents the striker from accidental movement in the direction of the primer cap. The foregoing described elements may be assembled into a compact unit with suitable sealing compounds to make the unit practically waterproof.

Practical embodiments of the fuze will be The bombs are made described with reference to the accompanying drawings, wherein:

Figure 1 shows a longitudinal cross-sectional view of a fuze unit assembly in one form;

Fig. 2 shows a plan of the fuze base illustrated in Fig. l;

Fig. 3 shows an end view of the fuze base in elevation;

Fig. 4 shows a longitudinal cross-sectional View of the safety plunger assembly enlarged;

Fig. 5 shows a bottom plan view of the striker arm;

Fig. 6 shows a side view of an all-ways modication of the fuze unit assembly with a part broken away and its safety plunger in an armed position;

Fig. '7 shows a longitudinal ycross-sectional view of the all-ways fuze illustrated in Fig. 6 rotated through an angle of about its longitudinal axis and with its safety plunger in an unarmed position;

Fig. 8 shows a cross-sectional View of the allways fuze taken along line 8-8 in Fig. 6.

Referring to the drawings, and particularly to Figs. 1 to 5, a cylindrical shell I of brass, steel tubing or similar tough metal construction serves as a relatively thin-walled protective containerv for the fuze mechanism. The wall of shell l is attached to the base 2 by engagement of a small bead protrusion 3 from the base into a correspending depression 4 in the shell l.

The base 2 is, in general, cylindrical in outline.

holds the safety plunger assembly 1. A well 8 perpendicular to the longitudinal axis of the fuze serves as a recess for a primer cap 9.

fuze and having aligned drilled holes I4 for holding a hinge pin I5. Small vent holes i 5 are drilled in the base transversely .to the long axis of the fuze with openings at the bottom of wen s. Y

A striker Il, preferably made of stamped steel or die cast aluminum base alloy. has parallel ears I8 pierced by aligned drill holes I9 through which the hinge pin is passed for holding the striker pivotally attached to the fuze base 2. At the free swinging end, the striker arm is weighted and carries a centrally disposed firing pin 20. In the assembled fuze the striker arm makes a small acute angle, with the longitudinal axis of the fuze, and lthe* point of the firing pin is held a short distance from the top of the primer cap 9 by the pressure of a torsion spring 2I looped around the hinge pin I5 with one end bearing against the fuze base 2 and the other end bearing against the striker arm I1, with shell I restricting further grooves 22 and 2, respectively, keep the ends of spring ZI from slipping sidewise.

The torsion spring 2l may be made of music wire about 0.04 in diameter looped aboutv 2% times around the hinge pin. Variations may be made, in thevr diameter and number of loops to adjust the degree of restraining action. 1.11 geleral, it. is desirable that, the restraining action by the spring be suiiicient to. prevent Contact oi the Striker lng pin 2i! with the primerwhen a bomib Icontaining the fuze impacts in falling a distance of about 2 to.. 5. ft.` onto a concrete floor, but definitely functions when dropped about; 9Y it.. Accordingly.. the iuze may be. Iina-de more or less sensitive depending uponA the. degree of safety desired, in. handling and conditions, under which the bomb is desired to operate.

safety plunger assembly 'I is of atvpe which has been manufactured on a.- .large scale, for usel in Standardized therrnit incendiary bombs, but some modication is made desirable by the relatively Small travel of the striker in the fuzeof the present invention. The safety plunger consists of. a thin-.walled Sleeve 24 made1 of brass, gilding metal, or the like, for. housing a, coiledspring 25 under compression and the stem 2.6l of a plunger pin,` the plunger nin having. a flange '2' which bears, against one end of spring 2,5. In the armed position. the, plunger pin has a button end 2 8 projecting outside4 the shell orsleeve 24,; and in an unarmed positiom the plunger pin is, pressed inwardly against the. spring; So that the. narrow, stem end 2t, of thev plunger pin: opposite the button endA 2R. projects into, the. fuze lindenA neath the striker l1 teufel/:ent movement there-A of. By inserting a thin Washer 33 ttecl closelyaround stem 2.6. between the compression. spring 2.5, and the. inner end of. the brass sleeve 24 the hole diameter at this end ofA the brass sleeve isy reduced and thereby; a.. better control of the plunger movement is obtained.

A. satisfactory procedure. for assembling.. the. fuzeis as follows:

(1'), Press the primer capii intothelwel-l 8; ofthe fuze. base. 2.;

(2.) Insert the. safety plunger assembly` l into the recess 6. in the fuze basel, havingthe plunger generously coated with a suitable. water resistant` grease,I e., g., a lithium base greasel toI keep out moisture.;

movement away. Small (13) Assemble the striker I1, hinge. Din isand.

torsion spring 2I to. the fuse, base; 2

(4) Insert the, spitter fuse II in the passage,.- way I'0V ofthe fuzebase 2. applyinga quick dryingcement, e.. g., Pettman cement, to hold it in, place,

and at' the. endsof the spitter, fuse apply a quick; match paste. of. black mealr powder mixed With; acetone and cellulose nitrate.

(5) Insert the fuze base thus assembled into thev cylinder' I until thel bead.. 3, on the.. base 2,

23 in the striker arm il. andbase.

I 2 into the f plunger.

Y The fuze thus assembled should be capable of ring in a bomb after the bomb is immersed in coldxwaterat 10.9' F. for l5 minutes.

lin operatiom when a bomb containing a fuze unit like that described becomes separated from a bomb cluster dropped from aircraft, the plunger pin being no longer pressed inwardly by an adjacenlibomb body in a cluster, becomes retracted outwardly by spring 25 to thus arm the fuze. The bomb drops, in aV generally' vertical position so that the'long axis of the uze. is. more or lesshorizontal to the grou-nd. Upon adequate. impact of the bombon a target surface, the inertia inthe weighted portion of the striker arm I1. forces. the striker ITI to overcome theA restraint of the toit-- sion spring 42i and swing downwardly in the direc-.- tion of the primer cap, 9.. The firing pin 2091iA being driven into the charge of. cap 9 flashes the primer material, which in turnignites, the under-L lying. end of the spittcr fuse I I- Thaspitter inse. gradually burns to its opposite. end in al period of about 1 to 5, seconds. andy thenignitesthe iirst fire charge in the cup I2., giving a, desired delay action which permits the, bomb to penetrate a, target and to. fall to rest on its side. before the. irst iire charge. detonates. a. propellant charge. disposed adjacent tor the fuzev unit.

Designed in accordance with the sameI principles that apply tothe fune. illustrated in Eig..1, but with.v certain modifications, an allfways. fuze, which is more responsive to impact in. all posi, tions i's obtained for use in incendi-ary, bombs,y grenades and'. other, munitions.` A description. of the all-ways fuze is. presented withreference. particularly to Figs. 6, '7,` and 8.. d

The all-ways fuze comprises twok 1....shaped.l

striker levers pivoted at. their corners.v on hinge pins I5. Eachofthe L-shaped levershasashort arm 'I carrying a firing pin Z0, and. each has` a. longerl arm IS': disposed generally vin parallel positions. rotational movement oi the longer arms 118 lio.-` wards they center of'Y the iuze serves to drive the firing pinV 2U of the integrally'moved short arm IT into. a. primer' cap- 9) ixed inthev funeA base 2, thereby causing firing of the primer. Movement of either, oithe longer arms Ira. toward the center of the iuze is. opposed b3ta'. spring 2 I. tend'sto keep the. longer arms t8l in a position substantially perpendicular. tothe baseand. parallel to. the lons axis of the fuse..` Thelenaer .arms la arel linked at about their. midfpoints by a taut. but 'exibleY wire or chain 3I to a relatively heavy weight 32. Movementof v1this weight 32 in. any direction tends to move one or Vboth ofthe, longy arms Hl4 towardjtlrev center of 'the fuse with sum.- cient fcrce'to overcome'the restraint of spring' 2 I thereby' rotating either or both striker levers onl their 'pivotsath-ingesfl so that the ring pins 20" on theshort striker arms I=1 are forced* irr the direction of' their. underlying primer caps 8.V When-.a munition; carrying the fuzereeei-vedfade--` quate impact, the momentum or inertia o'the Weight; 32 forces.r it. from; its' normal position and The L-sha'ped striker levers are.v

Aone or both caps 9 are fired through the rota- AOVelCOll'le.

The previously mentioned, base 2, to which the L-shaped levers are hinged in projections I 3 having aligned hinge pin bores I4, is provided with two primer caps 9. Each of the primer caps 9 is aligned under each of the ring pins 23 attached near the ends of each of the shorter arms i! of the striker levers. The primer cap wells and a vent-hole IS lead into an adjoining chamber, at the opposite end of which there is a central bore in externally threaded plug .Iii containing a pressed powder core II formed of a material, which is ignited when either one or both primers 9 are red and then burns in an approximately determined time delay period yof about one or a few seconds. At the nal burning end of this delay element, the base 2 has an attached plastic cup I2 filled with a booster or iirst re charge of black powder. This booster charge can detonate the main charge in a bomb, grenade, or other munition in which the fuze is used. The entire fuze is preferably assembled into a tube or hollow cylinder I which is constructed of a tough metal, such as steel or brass, to which the base 2 and the head having threaded end 2a are connected by means of small screws 33, or the like.

Likewise, in a manner similar to that employed in the fuze illustrated by Fig. 1, the all-ways fuze shown in Figs. 6, '7, and 8 may be provided with a simple safety means which is capable of keeping the fuze unarmed through the application of an external pressure in a cluster. This safety mechanism is one of the same general design as the safety plunger assembly shown in Fig. 4 except for the attachment of a metal disk 34 to the end of the plunger stem 25 opposite the button end 28. The extreme ends of the long arms I8 of the striker levers are bent over toward each other so that they terminate the periphery of the metal disk 34 when ton 28 and inwardly to unarm the fuze. long arms I8 of the striker lever are prevented from having any motion, and thus the fuze is rendered unarmed and safe. However, when the disk 34 is retracted on the outwardly ejected plunger as shown in Fig. 6, the long arms I8 of the striker levers are free to be actuated into movement by movement of weight 32 transmitted through links SI. The safety plunger assembly 'I may be fastened into recess 6 in the cylindrical head piece of metal. The head piece of the fuze is provided with thread 29 for engagement with a threaded hole in a munition. The head piece and base may be expeditiously made of die cast metal.

In free flight of a bomb or the al1-ways fuze, the safety plunger is ejected or retracted by a spring, as described with reference to Fig. 4. Upon impact of the bomb or projectile on the target, the suspended weight 32 being free to move in any direction, continues to move in the general direction of flight while the munition is decelerated by impact. Regardless of the direction of the motion, resulting force components pull one or both of the long arms I8 of the striker levers towards the fuze center-line. This motion of one or both of the striker levers causes one or both the primers 9 to be fired, which in turn ignites the pressed powder core Il of the delay element, then following the period of delay ignites the booster charge in cup I2.

projectile carrying 'I'he fuze may be made to operate instantaneously without delay by merely omitting the powder delay element or substituting therefore an instantaneous burning or detonating powder charge.

The types of primer, powder delay train, and booster charge which work well in the fuze are standard available materials. In tested fuzes which gave satisfactory results, new No. 4 primer caps manufactured for smokeless powder paper shot shells by Winchester Repeating Arms Co., New Haven,`Co'n"n.', and covered by U. S. Army Specifications on Primer, new No. 4 were used. For the delay train, lead spitter fuses (consisting in a black powder mixture contained in a lead tube) 'V8 inch length made by the Ensign- Bickford Co., IS'imsbury, Conn., and known as Type D were used. Army black powder, Grade A, No. l was used as a first nrev charge in cellulose nitrate plastic cups (about cellulose nitrate having approximately an 11% nitrogen content and plasticized by about 20% camphor), the cups having a wall thickness of about 0.0 1 inch, a depth of about Tag inch, and made tot snugly into a cylinder inch I. D. It will be understood, however, by those skilled in the art that variations may be made in the selection of the components, their ingredients and dimensions.

Fuze units made in accordance with this invention were subjected to extensive surveillance tests and met stringent requirements of standardization.

Some of the practical advantages of the fuze units are: (1) safety in assembling due to the independent restraining action of the torsion spring even when the safety plunger does not unarm the fuze; and (2) consistent cooperative action of the delay element and rst re charge with the primer in the combination unit.

It is to be noted that the fuze may be made of common materials with very small amount of machinery. The die casting of the fuze base, preferably of aluminum base alloy, greatly simpliies the construction, and very little tooling is needed for other portions of the fuze. Even though under some rigorous conditions, e. g., when a bomb has a high terminal velocity and impacts on concrete at an extremely low temperature on the order of minus 40 F., resulting in a fracturing of the die cast base, this failure does not prevent functioning of the ring mechanism since the outer case holds the fuze components intact.

Although the fuze embodiment illustrated in Fig. 1 functions most satisfactorily when such a fuze is positioned in a bomb body horizontally, so that its longitudinal axis is perpendicular to the longitudinal axis of the bomb, or so that the movement of the striker is in substantially the same direction as a night of the bomb just prior to impact, the fuze may be positioned near the tail end as well as near the nose end of the bomb. On the other hand, the more responsive all-way fuze embodiment such as illustrated in Fig. 7, may be xed in a bomb body or other type of munition in any position for satisfactory functioning, e. g., horizontally, vertically, or at any angle and in any part of the bomb or munition.

It is to be understood that although the invention has been described in detail with respect to preferred specific embodiments, that modifications come within the spirit and scope thereof.

I claim:

1. A combination fuze adapted for use in the 7 nose :end -o'f a -tail Aejection bomb, comprising a base having a generally 5cylindricaloutline defined by circular disc lportions forming the head and rear Aends of the ibase, a Aprimer charge -we'll 'located intermediate said head and rear ends'inthe base, a -pair of parallel Vlobes vaxljoining the rear end of the base, a pair VVVof drilled holes aligned'in said lobes to hold a hinge 12in, astriker lever 'pivotally mounted at one "end on ahinge -pin ypassed through said drilled Aholes, 'a weighted 'portion 'at the other end .of said lever, 'a firing pin 'in said striker 'lever vat its free swinging end, .a torsion spring coiled. around lsaid hinge pin with one fend bearing against 'the ystriker lever to Vrestrain its swinging movement, a'vented passageway leading .'from'the primer vwell inthe base 'to the rear end Yof the *nase for holding a powder train delay .ele-

ment, .a plastic cup 'for holding a Lrst fire charge adjacent the rear end of the base, and a metal cylinder` surrounding said .plastic .cup Iand fuze base up tothe head .end of the'base.

2. A `com'bina'tion uze as described Vin claim .1, in which the powder train vdelay element is inthe form of -a 'lead spitter fuse, the Yplastic Vcup is a cellulose nitrate `plastic, and :the `plastic cup contains a .blockpower first vlire charge.

3. A combination fuze as described in 'cla-lm '1, in which the Iuze `Ebase is a die -cast aluminum base alloy, .and the cylinder surrounding the -uze base is .made of a vpressed steel.

LYLE "`C'O'OPER l.References :Cited in the "le 0f this paient STATES PATENTS Number Y I .Name Date ,234,713 Asbury `July .31., y1917 1,311,739 Asbury vJuly 29, .119219 .FOREIGN PATENTS Number Country vDate 128,616 Great Britain e- 5111373, 1919 245,528 .Italy Mar. J12,1926 498,595 Great Britain Jan. 9,1939 `,9512'7 Sweden .Malt 2l, '193,9

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