US3351017A - Air-arming impact fuze - Google Patents

Description

Nov. 7, 1967 J. A. MYERS 3,351,017

Y AIR-ARMING IMPACT FUZE Original Filed D60. 5. 1964 2 Sheet S-Sheet 1 Ila FIG. IA. 24

FIG. 5.

INVENTOR. JACK A. MYERS FIG. 2.

ATTORNEY.

Nov. 7, 1967 J. A. MYERS AIRT'ARMING IMPACT FUZE Original Filed Dec. 5. 1964 2 Sheets-Sheet 2 INVENTOR JACK A. M YE RS ATTOR N EY.

United States Patent f ABSTRACT OF THE DISCLOSURE An inertia member is restrained in a safe a frustoconical washer which is deformed by a deceleration force, such as the opening of a parachute, permitting the inertia member to move to an arm position. Thereafter, the deceleration of impact permits the inertia member to move to fire position.

position by 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.

The instant invention, a continuation of Ser. No. 415,840, filed Dec. 3, 1964, now abandoned, relates generally to fuzes and more particularly to an improved airarming, impact-firing mechanical fuze of free-fall weapons.

Heretofore, various fuze mechanisms have been em ployed to fire air-delivered pyrotechnics on impact. However, known air-arming and impact-firing mechanisms have not satisfied existing needs, as such devices generally require complex and expensive actuating mechanisms, are normally diflicult to assemble, are often unsafe to handle and store, and are frequently found to be operatively unreliable.

Therefore, it is the purpose of the instant invention to overcome the aforementioned disadvantages, while improving over-all efiiciency. This is accomplished by providing a fuze for an air-delivered device, which may be coupled with existing hardware and ejected into an impinging airstream and subsequently armed as a malleable safety washer or buttress is crushed as a consequence of imposed shock resulting from a deployment of an attached delivery parachute.

An object of the instant invention is to provide an airarming, impact-firing mechanical fuze having reliable means for maintaining a positive safe condition and a reliable firing operative function.

Another object is to provide a fuze which may be readily attached to existing hardware and ejected from airborne aircraft, and subsequently armed by an impinging airstream acting on a deployed parachute attached thereto.

A further object is to provide a tamper-proof safety device having a positive retaining means for maintaining the fuze in a safe condition.

Still another object is to provide a simple, economic, and safe-to-handle, air-delivered pyrotechnique device, which is capable of deploying a delivery parachute, with a high degree of reliability, and arming as a consequence of parachute deployment.

Yet another object is to provide a pop off fuze which may be attached to existing pyrotechnic hardware for improving the burning characteristics of the hardware when delivered from an airborne vehicle.

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:

3,351,017 Patented Nov. 7, 1967 ice FIGS. 1A, 1B, and 1C comprise successive views of an ejected device of the instant invention undergoing parachute deployment and fuze-arming operations;

FIG. 2 is a partial cross sectional view, on an enlarged scale, taken along a vertical central plane 2-2 of FIG. 1A, illustrating a predelivery fuze, parachute and parachute housing relationship;

FIG. 3 is a cross sectional view of the fuze, on an enlarged scale, taken generally along lines 3-3 of FIG. 2;

FIGS. 4 and 6 comprise alternate cross sectional views, taken generally along lines 44 of FIG. 3', illustrating an alternate positioning of the stab detonator and rotor bar, as provided for the device of the instant invention in a safe, and subsequently, armed condition; and

FIG. 5 is a partial sectional view of the fuze of the instant invention illustrating the fuze in an armed condition.

Turning now the the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1A a grenade G including a pyrotechnic container C having a predetermined type and quantity of pyrotechnic material P disposed therein. The grenade G is of a type which may be inserted into and dispersed by ram air acting on a system such as that disclosed in applicants copending application Ser. No. 415,828, filed Dec. 3, 1964, or from tubular racks provided for attacking aircraft, not shown. Upon being dispersed, a parachute 10 is deployed from a housing 11 and arms a fuze F as the parachute opens and the grenade G descends at a rate which may be a non-lethal and non-destructive rate. Once the grenade G impacts, with a predetermined non-destructive force, the fuze is separated and the pyrotechnic material of the grenade G is permitted to burn at both ends simultaneously to effect a desired result. The pyrotechnic material P may comprise any one of a large number of chemical materials which are to be ignited and burned for various purposes.

As it is often desirable to use the herein disclosed weapon as a non-lethal device, the parachute 10 may be of a size sufficient for accommodating a descent rate of posed in a common plane, and

30 feet/second, which has been determined to be of a non-lethal rate. The housing 11 comprises a pair of connected clam shell-like members 11a and 11b utilized to encase the parachute 10 and fuze F, FIG. 2. The housing 11 may be fabricated as a unitary device of resilient synthetic plastic material. Thus in forming the housing 11, the members 11a and 11b are preferably connected along one adjacent edge by a plastic film (not designated), which extends between the two members, as they are diswill, if deformed, tend to recover for forcing the members 11a and 11b to assume an open condition wherein the members 11a and 11b are forced toward a common plane. Hence, when the grenade G is ejected into an airstream the housing 11 pops open, as the members 11a and 11b tend to separate. As the members 11a and 11b separate, the airstream acts thereon to completely open the housing 11 and extract the parachute 10 therefrom, whereupon the parachute 10 now becomes fully deployed for arming the fuze F, as will hereinafter be more fully explained, and the grenade G lowered thereby to the ground or impact area.

As more clearly shown in FIG. 2, the parachute 10 is attached, through its shroud lines 10a, to a shirt-like portion of a cap 12 and stored in a folded condition, about the fuze F, within the housing 11. Therefore, the grenade must necessarily be supported in descent by the cap 12. Thus forces of shock imposed through an opening of the parachute 10 will be transferred to the cap 12.

The cap 12, FIG. 3, is connected to an extended firing pin shaft 13 passing outwardly through an opening 12' formed in the cap 12 and concentrically arranged about the longitudinal axis of the fuze F. The extended shaft 13 serves to add mass to a firing pin 14, connected to or formed at the shafts innermost end, and further serves to aid in aligning the fuze F within the housing 11. Any suitable means may be employed for connecting the cap 12 and shaft 13. However, it is preferred to provide the shaft 13 with a shoulder 13a, which abuts the internal surface of the cap 12, and a lock ring 13b seated in an appropriate groove formed about the shaft 13in engagement with the external surface of the cap 12. Further, suitable O-ring seals 130 may be provided to seal the shaft 13 relative to the cap 12.

The shaft is further provided with a shoulder 15, disposed inwardly from the cap 12, which serves as an abutment against which a relatively thin safety washer or buttress 16 is seated for retaining the firing pin 14 in an inwardly extended or a safe position within a cup-shaped fuze housing 17 having an opening 17a formed therein for receiving the shaft 13. The buttress 16 is formed to assume a generally frusto-conical configuration from a malleable material, such as malleable aluminum, for example, whereby a crushing of the buttress is required in order to retract or displace the firing pin 14 from its safe position.

In assembling the fuze, it is desirable to first pass the shaft 13 through the washer or buttress 16 and then insert the shaft 13 through the opening 17a, which is provided at one end of the cup-shaped housing 17 in coaxial alignment with the opening 12' of the cap 12. Thus the buttress 16 is thus caused to assume a disposition wherein it engages the internal surface of the housing 17 while engaging the shoulder, and serves to maintain the shoulder in a displaced relationship relative to the internal surfaces of the end portion of the housing 17. Hence, it is to be understood that shoulder 15 may not be displaced rearwardly except in instances where applied displacing forces are suificient for crushing or deforming the buttress 16.

Therefore, it is entirely feasible to predetermine and dictate the forces required for retracting or displacing the firing pin 14 from its safe to its arm position. Thus the buttress 16 serves as a positive safety device which is not subject to vibrations normally encountered in handling and transporting the grenade G. Further, the fuze F is thus made substantially tamper-proof, due to the fact that it is disposed entirely within the fuze housing 17, which, when assembled, is further protected by the parachute 10 and housing 11. This characteristic is found to be highly desirable in instances where the device is to be placed in the hands of the inexperienced, or where the device is likely to become accessible to unfriendly personnel.

Mounted to pivot about a pivot post 18, and normal to the longitudinal axis of the fuze F, there is fixed a rotor bar 20, which may be displaced across the path of the firing pin 14 when the firing pin is in an armed position. The rotor bar 20 has formed therethrough an opening into which a stab primer or detonator 22, of conventional design, FIG. 6, is inserted and secured through a conventional staking process. In order to function as a means for initiating the grenade G, it is necessary that the stab primer 22 be so disposed as to locate, When in arm position, in coaxial alignment with the firing pin 14, whereby the firing pin may be caused to reciprocate for impinging on the surface thereof. Consequently, for arming the fuze F, the rotor bar 20 must be pivotally displaced from a safe position, wherein the primer 22 is out of coaxial alignment with the firing pin 14, to its arm position thus altering the successive positions assumed by the stab primer 22 as the device becomes armed.

It is to be particularly noted that when the device is in a safe condition, FIGS. 3 and 4, the firing pin 14 is fully extended inwardly into the fuze housing 17. Therefore, when a safe condition is imposed on the fuze F, the firing pin 14 must necessarily extend into the path of the rotor bar 20 and thereby serve to block pivotal displacement of the rotor bar 20 and thereby retain the stab primer 22 in a safe position, FIG. 4. Thus the firing pin 14 must be retracted from its safe position to its armed position, FIG. 5, in order to accommodate a pivotal displacement of the rotor bar 20 to an armed position, as illustrated in FIG. 6, wherein the stab primer 22 is coaxially aligned with the firing pin 14.

The rotor bar 20, and the pivot pin 18, are supported on a transverse bearing plate 23 which, in turn, is supported by a plurality of supporting bars 24 extending from a remotely disposed transverse supporting plate 24a, FIG. 3. Where desired, an additional transverse bearing plate 23a may be provided adjacent the surface of the bar 20 opposite the plate 23, and seated in a retainer ring 23b, for thus encasing the rotor bar 20 and providing opposed bearing surfaces upon which rotor bar bearings 20a may ride.

Mounted in coaxial alignment with the firing pin 14 is tubular conduit 25 which extends through the bearing plate 23 and supporting plate 24a, or from the rotor bar 20 to an igniter wafer 26. The wafer 26 is formed of any suitable pyrotechnic composition which is capable of igniting the particular pyrotechnic material P in response to its initiation, resulting from an explosion of the stab primer 22 and communicated thereto through the conduit 25. The wafer 26 is seated over an opening 27 formed in a container cover cap 28 and communicating with the selected pyrotechnic material P. The cover cap 28 is fixed to the container C across a container opening 0.

Hence, it is readily apparent that when the device is in an armed condition the firing pin 14 may be caused to impinge against the stab primer or detonator 22 for causing an explosion thereof. By-products of the explosion are then directed through the conduit 25 for initiating the igniter wafer 26 which, in turn, fires through the opening 27 and initiates the pyrotechnic material P.

In order to impart pivotal displacement to the rotor bar 20, an elongated cam slot 30 is provided in the bar 20 and receives a drive pin 31, FIGS. 4 and 6, which extends through an arcuate slot 32 formed in the bearing plate 23 so that the drive pin 31 may be oscillated for pivoting the bar 20 from a safe to an arm position. The drive pin 31 is driven by a conventional one-seconddelay timing mechanism including a torsion spring 33, gear train 34, escapement device 35, and a fly-wheel 36. The timing mechanism is of conventional design and functions to displace the drive pin 31 along the slot 32 at a given rate, as dictated by the operation of the gear train 34 and escapement device 35, so that the rotor bar 30, with the stab primer or detonator 22, may be displaced to an arm position, FIG. 6, whereby the primer 22 becomes coaxially aligned between the firing pin 14 and the igniter wafer 26 one second after the firing pin 14 has been displaced out of the path of the rotor bar 20.

In many instances it is necessary that the pyrotechnic material burn inwardly from both ends of the grenade Gin order to prevent flaming and/or detonation. Hence, 1t 13 necessary that means be provided for removing the fuze F and the cover cap 28 from the container C subsequent to impact. In the present invention, this result is effected by securing the cover cap 28 to the fuze housing 17 and to a neck portion 38, provided for the container C, by layers 37 of epoxy resin, which fracture as the stab primer or detonator 22 explodes and sets up a rebounding shock front, which effectively induces a tensile stress at the epoxy joint. Through this effect, coupled with a resulting peeling action occurring at the joint, separation of the container C from the fuze F, is achieved.

,In assemblying the device of the instant invention,

the fuze F is first assembled and attached to a parachute 10. The fuze F and parachute are then encased in the housing 11, FIG. 2, with the halves 11a and 1112 being secured together by suitable means, such as an adhesive strip A, FIG. 1A. With the fuze F thus packaged within the housing 11, assembly completion is effected by securing the fuze F to the neck 38 of a conventional grenade by means of an epoxy rain.

The assembled device may now' be inserted into a delivery device or a tube of an aircraft pod (not shown), of an attack aircraft with the adhesive strip A being removed therefrom as it is inserted. Once the aircraft is over the target, the device is ejected into the aircrafts airstream, whereupon the housing portions 11a and 11b tend to separate under the influence of the deformed hinge portion of the housing as it tends to recover. Once the portions 11a and 11b become separated, the airstream causes the portions 11a and 11b to separate and fall away from the fuze F and, further, serves to deploy the parachute 10, FIG. 1B. As the parachute deploys, or opens, a shock force is applied to the shroud lines 10a which causes the cap 12 to retract, relative to the fuze housing 17, carrying the firing pin 14 with it and cansing the buttress or safety was-her 16 to crush or deform. As the firing pin 14 is retracted, relative to the path of the rotor bar 20, the torsion spring 33 acting through the drive pin 31 causes the rotor bar 20 to displace the stab primer or detonator 22 into coaxial alignment with the igniter wafer 26, the conduit 25, and the firing pin 14 to thus impose an armed condition on the device. The device is now supported through the parachute shrouds 10a and may now float to the ground. On impact, the firing pin 14 is caused to impinge on and initiate the stab detonator 12 as the cap 12 is forced toward the container C. As the detonator or primer 22 is initiated, the epoxy layers 37 are fractured. The wafer 26 now ignites the pyrotechnic P, whereupon the fuze F is parted from the container C so that the pyrotechnic P may now burn from both ends in a desired manner.

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. An air-arming, impact operative device comprising, in combination:

an elongated fuze housing;

a pivotally mounted rotor bar disposed in said housing and mounted for pivotal displacement from a safe position to an arm position within a plane normal to the longitudinal axis of said housing;

a stab detonator disposed within said rotor bar and adapted to extend between opposite faces of said rotor bar and being concentrically aligned with said longitudinal axis when said bar is pivotally displaced from said safe position to said arm position;

an operative timing device connected with said bar and adapted to constantly apply a pivoting force to said bar for driving said bar in displacement from said safe position to said ar-m position at a given rate;

an igniter wafer mounted concentrically about said longitudinal axis in communication with a given pyrotechnic composition;

a conduit mounted to extend between said Wafer and said detonator adapted to establish communication therebetween when said rotor bar is disposed in an arm position;

a reciprocating firing pin mounted for reciprocation along said longitudinal axis adjacent said rotor bar and adapted to extend into a bar displacement obstructing engagement with said rotor bar for maintaining said rotor bar in said safe position;

a collapsible buttress mounted in fixed relationship housing,

with respect to said fuze housing and in supporting engagement with said firing pin for maintaining said firing pin in displacement obstructing engagement with said rotor bar;

a skirt-like cap member telescoped in longitudinal sliding relationship about said housing and fixedly connected with said firing pin;

a parachute adapted to be deployed in an airstream; and shrouds connecting said parachute with said skirt-like member adapted to slidingly retract said skirt-like member with respect to said housing as said parachute is deployed, whereby said firing pin is caused to be retracted by said parachute against said buttress to collapse the buttress and be displaced out of engagement with said rotor bar for accommodating a pivotal arming displacement of 7 said bar so that said firing Pin may subsequently impinge against said stab detonator for firing said pyrotechnic composition as said device is caused to impact against a given target. 2. The device of claim 1 further including a parachute housing mounted about said device adapted to retain said parachute in a folded condition and subsequently release said parachute for deployment as the device is subjected to an airstream.

3. The device of claim 2 further characterized in that said parachute housing comprises a pair of clam shelllike members connected along portions of their circumference by a resilient hinge means adapted to apply a member separating force to said members for releasing said parachute and separating from said device.

4. An air-arming impact firing device for firing a given pyrotechnic composition comprising in combination:

a device housing;

means mounted in said housing adapted to fire said pyrotechnic composition including a stab detonator and a displaceable firing pin operatively associated with said detonator and adapted to be displaced from a safe position through an arm position to a position for impacting said stab detonator;

a buttress formed of malleable material operatively connected with said firing pin and supporting the firing pin in a safe position until such time as a force of a buttress deforming magnitude is applied to said firing pin as the firing pin is driven from its safe to its arm position, whereby said firing pin may be maintained in its safe position against forces of less than a buttress deforming magnitude as it is applied to said firing pin;

an inertia weight afiixed to the firing pin and moveable in unison therewith; and

a parachute having shroud lines connected to said inertia weight;

the construction and arrangement being such that when the parachute opens it applies the buttress deforming force to the firing pin and maintains the firing pin in arm position until the device impacts an object, whereupon the shroud lines slacken and permit the inertia weight to move, carrying the firing pin into contact with the detonator.

5. The device of claim 4 further characterized in that said buttress is a frusto-conical disk surrounding the firing pin, its smaller end abutting a shoulder on the firing pin and its larger end abutting an end wall of the the disk, when deformed, being substantially flat.

6. Apparatus for arming and firing a moveable ordnance member subjected to acceleration and deceleration forces, comprising:

a weight carried by the member and restrained against movement from a safe initial position by a deformable frusto-conical washer, having freely slidable abutment edges at opposite ends thereof, the smaller edge adapted to decrease in diameter and the larger edge adapted to increase in diameter whem the washer is deformed toward a flattened position;

said weight adapted to move rearwardly relative to the direction of movement of the member and flatten said washer upon application of a force acting relative to the weight and washer;

said weight being in armed position when the washer is flattened;

said weight adapted to move forwardly relative to the direction of movement of the member to a firing position by its inertia when the member rapidly decelerates; and

an igniter adapted to be initiated by the Weight when the weight moves to firing position.

7. Apparatus for arming and firing an ordnance member subject to acceleration and deceleration forces comprising:

an inertia member carried by said ordnance member adapted to move between a safe and arm position;

a deformable frusto-conical washer, engaging said inertia member and restraining said inertia member against movement from the safe position;

said washer having freely slideable abutment edges at opposite ends thereof, the smaller edge adapted to decrease in diameter and the larger edge adapted to increase in diameter when the washer is deformed toward a flattened position;

said inertia member being adapted to move relative to the washer upon application of a force on said inertia member sufficient to deform said frustoconical member;

said inertia member being in an armed position when the washer is deformed.

References Cited UNITED STATES PATENTS 1,311,678 7/1919 Cartwright 102-78 1,356,828 10/ 1920 Rockwell 10278 2,764,092 9/1956 Massey lO2-73 SAMUEL FEINBERG, Primary Examiner.

BENJAMIN A. BORCHELT, Examiner.

G. H. GLANZMAN, Assistant Examiner.

Claims (1)

1. 7. APPARATUS FOR ARMING AND FIRING AN ORDNANCE MEMBER SUBJECT TO ACCELERATION AND DECELERATION FORCES COMPRISING: AN INERTIA MAMBER CARRIED BY SAID ORDNANCE MEMBER ADAPTED TO MOVE BETWEEN A SAFE AND ARM POSITION; A DEFORMABLE FRUSTO-CONICAL WASHER, ENGAGING SAID INERTIA MEMBER AND RESTRAINING SAID INERTIA MEMBER AGAINST MOVEMENT FROM THE SAFE POSITION; SAID WASHER HAVING FREELY SLIDABLE ABUTMENT EDGES AT OPPOSITE ENDS THEREOF, THE SMALLER EDGE ADAPTED TO DECREASE IN DIAMETER AND THE LARGER EDGE ADAPTED TO INCREASE IN DIAMETER WHEN THE WASHER IS DEFORMED TOWARD A FLATTENED POSITION; SAID INERTIA MEMBER BEING ADAPTED TO MOVE RELATIVE TO THE WASHER UPON APPLICATION OF A FORCE ON SAID INERTIA MEMBER SUFFICEINT TO DEFORM SAID FRUSTOCONICAL MEMBER;

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