US2737117A - Fuze - Google Patents

Description

Marchfi, 1-956 M. COOPER Original Filed Nov. 7, 1944 BY 2 E ATTORNEY INVENTOR. Lyle M. Cooper United States FUZE Lyle M. Cooper, Rahway, N. J., assignor to the United gt ates of America as represented by the Secretary of Original application November 7, 1944, Seriai No. 562,370, now Patent No. 2,666,389, dated January 19, 1954. Divided and this application June 10, 1953, Serial No. 360,734

3 Claims. (Cl. 102-73) This application is a divisional application of my copending patent application Serial No. 562,370, filed November 7, 1944, entitled Fuze, now Patent 2,666,389, granted January 19, 1954.

This invention relates to a combination percussion and time fuze or firing 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. The bombs are made 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 firing the ejection charge.

An object of the invention is to provide a fuze sufiiciently compact to increase the loading etficiency of the bomb, simple for safe handling, easy assembly and man facture 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.

It is a specific object of this invention to provide an allways fuze which is responsive to impact regardless of the angle of impact made by the bomb with regard to the target, thereby being particularly suitable for incendiary bombs, grenades and the like.

The above and other objects of the invention will become apparent from the accompanying drawings, where- Fig. 1 is a side view of the all-ways fuze unit with a part broken away and its safety plunger in its armed position.

Fig. 2 is a longitudinal, cross-sectional view of the allways fuse illustrated in Fig. 1, rotated through an angle of 90 about its longitudinal axis, and with its safety plunger in its unarmed position.

Fig. 3 is a cross sectional view taken on line 3-3 in Fig. 1.

Fig. 4 is a longitudinal cross section of the safety assembly.

Referring to the drawings, my improved, all-ways fuze comprises a casing 1 which is made of brass, steel tubing or similar tough metal, which houses base 2 in one end thereof. Base 2 is provided with a pair of axially inwardly extending projections 13 on each lateral side thereof (see particularly Fig. 3), and two primer caps 9 mounted in its inwardly facing side. Projections 13 have aligned hinge pin bores 14 formed therein which are adapted to receive hinge pins 15. Two L-shaped striker levers are pivoted at their corners on hinge pins 15. Each of the L-shaped levers has a short arm 17 carrying a firing pin 20, and each has a longer arm 18 which is bent at its end opposite to the one having short arm 1'7. The L-shaped striker levers are disposed generally in 2,737,117 Patented Mar. 6, 1956 parallel positions. Any rotational movement of the bent ends of the longer arms 18 towards the center of the fuze serves to drive the firing pin 20 of the integrally moved short arm 17 into a primer cap 9 fixed in the fuze base 2, causing firing of the primer. Movement of either of the longer arms 18 toward the center of the fuze is opposed by a spring 21 which tends to keep the longer arms 18 in a position substantially perpendicular to the inwardly facing side of the base 2 and parallel to the long axis of the fuze. The longer arms 18 are linked at about their mid-points by a taut but flexible wire or chain 31 to a relatively heavy weight 32. Movement of this weight 32 in any direction tends to move one or both of the long arms 18 toward the center of the fuse with sufficient force to overcome the restraint of spring 21, thereby rotating either or both striker levers on their pivots at hinges 15 so that the firing pins 20 on the short striker arms 17 are forced in the direction of their underlying primer caps 9. When a munition carrying the fuze receives adequate impact, the momentum or inertia of the weight 32 forces it from its normal position and one or both caps 9 are fired through the rotational movement of one or both of the striker levers with the restraining pressure of spring 21 overcome.

The primer caps 9 are mounted in primer cap wells formed in the inwardly directed face of the base 2, and are aligned with the firing pins 20. The primer cap wells and a vent-hole 16 lead into an adjoining chamber, at the opposite end of which there is a central bore in externally threaded plug 10 containing a pressed powder core 11 formed of a material which is ignited when either one or both primers 9 are fired and then burns in an approximately determined time delay period of about one or a few seconds. At the final burning end of this delay element, the base 2 has an attached plastic cup 12 filled with a booster or first fire 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 all-ways fuze may be provided with a simple safety means which is capable of keeping the fuze unarmed in a cluster. The safety plunger assembly 7 is mounted in a recess 6 formed in a head which is mounted in the casing 1 at the end opposite to the one in which the base 2 is mounted. It should be noted in this connection that conventional securing means 33 are used to secure both the base and the head in position in the casing 1. The safety plunger assembly 7 is of the type which has been used in standardized incendiary bombs but some modification has been made to adapt it to applicants fuze because of the relatively small distance that the striker levers travel. The safety plunger assembly 7 includes a plunger pin 26 that has a button end 28 projecting out of the head and a disk 34 secured to its inner end. This safety mechanism is of the same design as that of Fig. 4 of Patent 2,266,389 except for the attachment of disk 34. It comprises a thin-walled sleeve 24 made'of brass, sliding metal or the like, housing a coiled spring 25 under compression and the stem 26 of the plunger pin. The plunger pin has a flange 27 which bears against one end of spring 25. A thin washer 30, fitted closely around stem 26 between the compression spring and the inner end of the brass sleeve 24, enables better control of the plunger movements. The plunger pin 26, which is normally spring pressed to its armed position (shown in Fig. 1), may be forced to its unarmed position shown in Fig. 2, wherein the disk 34 is located between the inwardly-directed, bent ends of the long arms 18 of the striker levers, thereby preventing motion of the striker levers and maintaining the fuze unarmed. When the bombs are released from the cluster and dispersed, plunger rod 26 is urged to its armed position wherein the disk 34 no longer prohibits movement of the striker levers. Threads 29 are provided on the exterior of the head to facilitate mounting of a fuze in a munition.

Upon impact of the bomb or projectile having the described all-ways fuze 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 18 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 11 of the delay element, then following the period of delay ignites the booster charge in cup 12. The fuze may be made to operate instantaneously without delay by merely omitting the powder delay element or substituting therefor 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, Conn., and covered by U. S. Army Specifications on Primer, new No. 4 were used. For the delay train, a lead spitter fuze (consisting of a black powder mixture contained in a lead tube) inch length made by the Ensign-Bickford Co., Simsbury, Conn., and known as Type D were used. Army black powder, Grade A, No. 4 was used as a first fire charge in cellulose nitrate plastic cups (about 80% cellulose nitrate having approximately an 11% nitrogen content and plasticized about 20% camphor), the cups having a wall thickness of about 0.01 inch, a depth of about 7 inch, and made to fit 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.

In addition to their primary attribute of being efiicient all-ways fuzes some 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 unarrn the fuze; and

(2) Consistent cooperative action of the delay element and first fire 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 simplifies 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 firing mechanism since the outer casing holds the fuze components intact.

My all-ways fuze may be fixed 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 a preferred specific embodiment, that modifications come within the spirit and scope thereof.

I claim:

1. An all-ways fuze comprising an elongated casing, a base in one end of said casing, two primer charges spaced apart on said base, two substantially rigid strikers each formed of a longer arm and a shorter arm arranged substantially at right angles to each other, said strikers being pivotally mounted on hinge pins in such positions that the longer arms extend at opposite sides of said casing substantially parallel to the longitudinal axis thereof, a firing pin rigidly mounted on each shorter arm, in alignment with and spaced a short distance from and of said primer charges, spring means acting on said strikers in such directions as to normally hold said firing pins away from said primer charges, a weight mounted between the longer arms in such a manner as to be capable of movement in any direction, and at least one flexible strand connecting said weight to said longer arms at points remote from said shorter arm, whereby movement of said weight in any direction will move at least one of said firing pins toward its corresponding primer charge.

2. A fuze as defined in claim 1 and further comprising a restraining member interposed between said longer arms in such a position as to prevent their movement toward each other, and resilient means for moving said restraining means out of engagement with said arms to thereby arm said fuze.

3. An all-ways fuze comprising a substantially cylindrical casing, a base mounted in a first end of said casing, said base having a central bore, a booster charge mounted in the outer end of said base in communication with said bore, two spaced primer charges supported by the inner end of said base in communication with said bore, two hinge pins mounted diametrically opposite each other on the inner end of said base, a substantially rigid striker pivotally mounted on each hinge pin, each of said strikers comprising a longer arm extending along said casing from said hinge pin substantially parallel to the axis of said casing and a shorter arm extending across said casing from said hinge pin, a firing pin rigidly mounted on each of said shorter arms in alignment with and spaced a short distance from one of said primer charges, a substantially U-shaped spring passing about said hinge pins and having its ends engaging said longer arms in such a manner as to normally hold said firing pins away from said primer charges, a weight mounted between said longer arms in such a manner as to be capable of movement in any direction, at least one flexible strand joining said weight to each of said longer arms at points remote from said hinge pins, the ends of said longer arms being bent radially inward, a head mounted in the second end of said casing, an axially movable plunger mounted in said head with its axis parallel to the axis of said casing, said plunger being movable from an outer position in which it projects outwardly beyond said head to an inner position, a spring urging said plunger toward said outer position, and a disk on the inner end of said plunger, said plunger and disk being so proportioned that when said plunger is in said inner position said disk lies between said ends of said longer arms and prevents inward movement of said longer arms, and when said plunger is in said outer position, said disk clears said ends, thereby arming said fuze.

References Cited in the file of this patent UNITED STATES PATENTS 559,495 Rapieff May 5, 1896 1,234,713 Asbury July 31, 1917 1,242,053 Shinkle Oct. 2, 1917

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