US3311060A - Mechanical fuze of the stator-rotor type with pivoted safety weights and detonator carrier - Google Patents

Description

March 1967 G.T. KELLER ETAL 3,31

MECHANICAL FUZE OF THE STATOR-RQTOR TYPE WITH PIVOTED SAFETY WEIGHTS AND DETONATOR CARRIER Filed June 9, 1965 INVENTORS.

GEORGE T. KELLER BY RONALD E BARKER ATTORNEYS.

United States Patent 3,311,060 MECHANICAL FUZE OF THE STATOR-ROTOR TYPE WITH PIVUTED SAFETY WEIGHTS AND DETONATOR CARRIER George T. 'Keller, Richmond, and Ronald F. Barker,

Centerville, Ind., assignors to Avco Corporation, Richmond, Ind., acorporation of Delaware Filed June 9, 1965, Ser. No. 462,607 3 Claims. (Cl. 10279) ABSTRACT OF THE DISCLOSURE This mechanical fuze has an annular stator carrying a spring biased circular rotor. The stator carries. two pivotally mounted safety weights and a pivotally mounted detonator carrier, the pivot points being spaced by 120. Under spin-generated forces the weights swing outwardly and are unlocked from the rotor but the carriage holds the rotor until diminution of centrifugal forces permits the spring to turn the rotor, which rotor is formed to cause the safety weights and carriage element to be swung inwardly to arm the detonator.

The present invention relates to mechanical fuzes for utility in shells, grenades, rockets and similar devices which spin in flight. These devices are hereinafter collectively referred to, for purposes of brevity, as missiles. It will be understood that conventionally the spin is clockwise looking into the base of the missile.

The principal object of the invention is to provide a relatively simple fuze mechanism consisting of a relatively small number of parts. While conventional mechanical fuze devices generally utilize several combinations of weights and springs in order to insure safety in the presence of shock and vibration, together with additional devices required to move a detonator from an out-of-line position to alignment with a firing train, the fuze in accordance with the invention utilizes only a single spring and a relatively small number of moving parts.

In accordance with the invention there is provided:

In a mechanical fuze the combination of a rotor 11 having a plurality of locking and positioning formations 25, 32 and 26, 33 and a holding and positioning formation 30, energy storage means 12 urging the rotor in one angular direction (counterclockwise);

A stator A plurality of swingable centrifugal-force responsive safety elements 13, 14 mounted on the stator and formed to engage the locking portions 25, 26 of the locking and positioning formations on the rotor and to restrain the rotor against angular motion in said direction until a threshold of centrifugal force is attained, a detonator 19, a swingable centrifugal-f0roe-responsive detonator-carriage element mounted on the stator and formed to engage the holding portion of the holding and positioning formation to cooperate in holding the rotor against movement in that direction until said threshold is attained, the attainment of such threshold swinging the safety elements sufficiently outward to disengage them from the locking portions and to engage them with the positioning portions 32, 33 of the locking and positioning formations, whereupon the carriage element continues to engage the holding portion of the holding and positioning formation to hold the rotor until the centrifugal force diminishes to such an extent as to permit the rotor to begin to turn in said direction whereupon the safety elements and carriage element are positioned inwardly by their respective formations to place the detonator in armed position (in alignment with 21).

For a better understanding of the invention together with other and further objects, advantages and capabilities thereof, reference is made to the following description of the accompanying drawings in which:

FIG. 1 is a front view of a fuze in accordance with the invention, with the face plate removed;

FIG. 2 is an elevational sectional view as taken along section line 22 of FIG. 1, looking in the direction of the arrows;

FIGS. 3, 4 and 5 are simplified front views provided to illustrate the configurations of the parts during the following phases of operation: safe, pre-arrned, and fully armed, respectively.

Making reference now particularly to FIGS. 1 and 2, the mechanical fuze there shown is adapted to be installed in a spinning missile or the like. It comprises a body member or stator 10 which is generally cylindrical in form, with an annular wall providing a cylindrical chamber in which a rotor 11 is mounted. The arrangement of this fuze is such that when the rotor member is positioned counterclockwise relative to the body member then the fuze is fully armed (FIG. 5 When the rotor member is positioned near its clockwise limit then the fuze is safe (FIG. 3). When the rotor is approximately at its clockwise limit the fuze becomes pre-arrned (FIG. 4).

Torque urging the rotor member toward its counterclockwise or firing position is provided by an energy storage means in the form of a spiral torsion spring 12, one end of which is fastened to the rotor and the other end of which is secured to the stator 10.

The parts now described function in static condition or in cooperation with the centrifugal forces developed during the initial high rate of spin of the missile and the later diminished spin, to restrain or control the rotor in such a way that it is safed, pre-armed and armed, as desired.

A plurality of swingable weights or centrifugal forceresponsive elements 13, 14 and 15 are pivotally mounted on the body member or stator 10 at points symmetrically disposed thereon and located degrees from each other, with their pivots 16, 17 and 18 at the same radial distances with respect to the central axis of the rotor and the housing or stator. A detonator 19 is carried on the outer end of the weight 15 which is hereinafter variously referred to as the detonator-carrying weight or carriage element. The other weights 13 and 14 are hereinafter referred to as safety weights or safety elements for reasons explained below. The three gross weights are identical in size, weight and configuration, this statement assuming that the weight of the stab-sensitive type of detonator 19 is effectively included in the figure for the detonator-carrying weight.

The weights swing within two plane surfaces formed by a face plate 20 on one side and the rotor 11 on the other.

Disposed with its point projecting into a central aperture 21 in rotor 11 is a firing pin 22 which is positioned by a spring plate 23. The firing pin is caged within a cover 24 which is preferably fitted into the plate 20 in such a manner that the entire fuze assembly is a hermetically sealed unit.

Referring now briefly to FIGS. 3, 4 and 5, they illustrate the parts in the safe, pre-arm and arm positions, respectively. In the safe position the swingable weights 13, 14 and 15 are symmetrically disposed with their outer or flee end displaced sufiiciently radially outwardly that the detonator 19 is out of line with the firing train (i.e. with aperture 21), in fact so substantially out of line that the detonator cannot initiate an explosion even if accidentally considerably displaced. In this position, cam projections on the weights 13 and 14 prevent the rotor from turning counterclockwise. In the safe position, the fuze is both statically and dynamically balanced, and is not sensitive to shocks or vibrations in the direction parallel to the axis of the housing, there being then no force tending to swing any of the three weights. As to forces parallel to the rotor, any tendency of any of the weights to rotate is resisted because they are all restrained by grooves formed in the rotor, the result being that the rotor remains locked.

More specifically, the rotor member is formed with locking grooves 25 and 26, diagonally extending radially inwardly and clockwise. These locking grooves accept cam- like projections 27 and 28, formed on the safety weights. In the safe position, safety weight projection 27 abuts against the inner end of locking groove 25 and safety weight projection 23 abuts against the inner end of locking groove 26, whereby the rotor 11 is restrained against counterclockwise movement. Additionally, the rotor exerts tangential force which keep the weights 13 and 14 from swinging outwardly.

Referring now to the detonator-carrying weight 15, it is formed with a cam-like projection 29 that fits into an arcuate holding and positioning groove 30 which is cut in the rotor 11. The holding and positioning groove is formed clockwise. It extends radially inwardly with a clockwise lead. In the safe position the concave or left hand side of this groove (as viewed in FIG. 3) exerts a restraining force on the weight 15 and prevents it from swinging, so that all three of the weights are locked in place as against forces of the order encountered during the usual handling and storage and firing-preparation and installation of the fuze. That is to say, in the absence of centrifugal forces of sufiicient strength to swing all of the safety weights outwardly the fuze is safe (FIG. 3) and, for all practical purposes, the detonator 19 cannot be aligned with the firing train.

Let us now consider the pre-armed condition illustrated in FIG. 4. The action of the centrifugal force imparted to the weights when the missile carrying the fuze spins at a high rate during flight is such as to overcome the spring-urged restraint on the weights imposed by the rotor, whereby the free ends of the weights swing radially outwardly, turning the rotor 11 slightly clockwise, freeing the projections 28 and 27 from the locking grooves 26 and 25, respectively. That is, the projections on the safety weights are disengaged from the locking groove portions of the locking and positioning formations. Reiteratin-g, only under centrifugal force attained when the fuze is rotating about its geometric axis do the forces against the three weights cause them to rotate or swing about their respective axes or pivots and to swing outwardly. Each cam-like projection then exerts a force against its respective cam groove, as the case may be, and when the three combined forces result in a torque greater than that of the spiral spring 12, the rotor turns slightly clockwise. As the rotor begins this slight angular displacement, each of the weights swing further outwardly so that a rapid transition is made from the safe to the prearmed position illustrated in FIG. 4, at which the free ends of all three weights are at their maximum outward positions. Under this condition of operation the detonator-carrying weight 15 functions as a holding weight and the arcuate groove 30 functions as a holding groove in that the left or concave side (FIG. 4) of the groove 30 has exerted against it a thrusting force by projection 29 on weight 15, which force prevents rotor 11 from turning counterclockwise. In other words, the projection 29 exerts a clockwise force against the holding groove 30 to restrain the rotor against counterclockwise displacement during the pre-armed phase of operation.

As the spin of the missile decreases, the spring-urged counterclockwise and radially inward force exerted by the right or convex side of groove 30 against cam projection 29 begins to prevail over the action of the centrifugal force on weight 15 and weight 15 accordingly begins to swing inwardly. This is made possible by the fact that the locking grooves 25 and 26 are fore-shortened and are formed in communication with arcuate positioning grooves 32 and 33. These are formed in the rotor member with radially inward and clockwise leads in order to permit counterclockwise rotation of the rotor 11 (urged by the spring) to swing the locking weights 13 and 14 inwardly (FIG. 5). The formations 25, 32 and 26, 33 are therefore referred to as locking and positioning formations.

Stating the initiation of the arming phase in another way: As the spin of the missile diminishes, a threshold is reached at which the rest-raining torque against the rotor 11 exerted by the tangential components of the detonator holding weight is less than the torque of the spring 12. At this time the rotor begins to move counterclockwise, rotating the ends of all the weights inwardly, the inward radial lead of groove 30 being substantially greater than that of grooves 32 and 33. The free end of the detonator carrying weight 15 is therefore swung much further inwardly than the free ends of the other two weights in order to align the detonator 19 with the firing train (FIG. 5). A significant aspect of the arming sequence i that, once the weights begin to rotate inwardly, the unbalance between centrifugal force and the constant spiral spring torque rapidly increases, thereby providing a rapid transition from the re-ar-med to the fully armed position illustrated in FIG. 5.

Upon impact of the missile, the inertial firing pin 22 moves forward against the restraint of spring plate 23 to penetrate detonator 19 and initiate explosion.

While there has been shown what is at present considered to be the preferred embodiment of this invention, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the proper scope of the invention as defined in the claims.

For example, the missile here spins clockwise and, pin 22 pointing forwardly, the FIG. 1 embodiment spins counterclockwise. The FIG. 1 embodiment also operates in a counterclockwise spinning missile.

Having fully disclosed our invention, we claim:

1. In a mechanical fuze the combination of a rotor having a plurality of locking and positioning formations and a holding and positioning formation, energy storage means urging the rotor in one angular direction;

a stator;

a plurality of swingable centrifugal-force responsive safety elements mounted on the stator and formed to engage the locking portions of the locking and posi= tioning formations on the rotor and to restrain the rotor against angular motion in said direction until a threshold of centrifugal force is attained, a detonator, a swingable centrifugal-force-responsive detonator-carriage element mounted on the stator and formed to engage the holding portion of the holding and positioning formation to continue to hold the rotor against movement in that direction even after said threshold is attained, the attainment of such threshold swinging the safety elements sufficiently to disengage them from the locking portions and to engage them with the positioning portions of the locking and positioning formations, whereupon the carriage element continues to engage the holding portion of the holding and positioning formation to hold the rotor until the centrifugal force diminishes to such an extent as to permit the rotor to begin to turn in said direction whereupon the safety elements and carriage element are positioned radially inwardly by their respective positioning formations to place the detonator in armed position.

2. In a mechanical fuze for a missile having a firing train, the combination of a rotor having an axis in line with said firing train and also having a plurality of locking and positioning formations and a holding and positioning formation, energy storage means urging the rotor in one angular direction, a stator in which the rotor is mounted, and means for controlling the rotor to place it in safe, pre-armed, and armed positions, comprising:

a plurality of swingable safety weights mounted on the stator and formed to engage the locking and positioning formations on the rotor and to lock the rotor safe against angular motion in said direction;

being formed with a cam projection;

6 weights, the other weights being identified as safety weights; the rotor member being formed with locking grooves diagonally extending radially inwardly and clocka detonator; 5 wise, individual locking grooves being provided to another swingable detonator-carrying weight mounted accept the projections on the safety weights;

on the housing and formed to engage the holding an arcuate holding and positioning groove, formed portion of the holding and positioning formation to clockwise in said rotor and extending inwardly with restrain the rotor against angular motion in that dia radial and clockwise lead which accepts the projecrection, all of the aforementioned weights being lo- 10 tion on the detonator-carrymg weight, the locking cated symmetrically to maintain static and dynamic grooves being so formed as to engage the pro ections balance, said safety weights beingresponsive to the on the safety weights to restrain the rotor against centrifugal forces developed by sp n to be displaced counterclockwise movement, whereby the rotor is sufficiently radially outwardly to disengage the safety locked in a safe clockwise position in the absence of weights from the locking portions of the locking and centrifugal forces which swing the safety weights positioning formations and to engage them with the outwardly, the-action of centrifugal force imparted positioning polrtiltlms offtthe locllltingi anld positioning wltienb the missl lle cattrrying theh fuzef spins atha high ormations, a t' e sa e y weig ts isp acing e rora e emg suc as 0 swing e sa ety weig ts outtor sufliciently in the reverse angular direction to acwardly, whereby the projections on the safety weights complish such disenigager ent, wherguplintihthg rotor tfiisenglige fromt the loctlging1 groozes to pre-armtlliltz assumes a pre-arme con i ion in w ic e e onauze, e pro ec ion on e e ona or-carrymg weig tor-carrying weight restrains the rotor by engagecontinuing to be urged outwardly to exert a clockment with the holding portion of the holding and wise thrust against the holding portion of the holdpositioning formation, diminution in said centrifugal ing and positioning groove to restrain the rotor durforces due to dirrlilinishing spinbreducingi the restiraint ing tllie pre-agmed pltilase ofh operation handhuntil tihe and permitting t e rotor to e move in sai anmissie spin iminis es, w ereupon t e t rust egular direction, whereby the positioning portions of creases to permit counterclockwise rotation of the the locking and positioning formations swing the rotor in response to the spring, arcuate positioning safety weights radially inward and the positioning grooves in communication with said locking grooves portion of the holding and positioning formation and formed in such rotor member with a radially inslwmgs the detonaltlorifary ng :ve ght ll'lvlgald is, aflign glard and tclockwiseflllead E0; permithsaid rotaitlion lof t e detonator wit t e ring rain, so t at t e uze e ro or 0 swing e sa e y weig ts inwar y, t e assumes an armed condition. positioning portion of the arcuate holding and posi- 3. A mechanical fuze adapted to be installed in a tioning groove simultaneously swinging the detonaspinning missile or the like comprising: tor-carrying weight inwardly, that holding and posia body member; tioning groove having sufiicient length that as the a rotor within the body member constructed and ardetonatoracarrying weight swings inwardly the detranged to be positioned counterclockwise when the onator is aligned with an axially positioned firing fuze is armed; train to arm the fuze. a torsion spring between the body member and the 40 rotor for turning the rotor counterclockwise unless References Cited y the Examiner the rotor is restrained; UNITED STATES PATENTS a plurality of weights having leading ends and trailing ends and pivotally mounted on the body member at 3 1 et a1 1O2 '79 points symmetrically disposed thereon, each weight lane 1 102 79 BENJAMIN A. BORCHELT, Primary Examiner. G. H. GLANZMAN, Assistant Examiner.

adetonator carried on the outer end of one of said

Claims (1)

1. IN A MECHANICAL FUZE THE COMBINATION OF A ROTOR HAVING A PLURALITY OF LOCKING AND POSITIONING FORMATIONS AND A HOLDING AND POSITIONING FORMATION, ENERGY STORAGE MEANS URGING THE ROTOR IN ONE ANGULAR DIRECTION; A STATOR; A PLURALITY OF SWINGABLE CENTRIFUGAL-FORCE RESPONSIVE SAFETY ELEMENTS MOUNTED ON THE STATOR AND FORMED TO ENGAGE THE LOCKING PORTIONS OF THE LOCKING AND POSITIONING FORMATIONS ON THE ROTOR AND TO RESTRAIN THE ROTOR AGAINST ANGULAR MOTION IN SAID DIRECTION UNTIL A THRESHOLD OF CENTRIFUGAL FORCE IS ATTAINED, A DETONATOR, A SWINGABLE CENTRIFUGAL-FORCE-RESPONSIVE DETONATOR-CARRIAGE ELEMENT MOUNTED ON THE STATOR AND FORMED TO ENGAGE THE HOLDING PORTION OF THE HOLDING AND POSITIONING FORMATION TO CONTINUE TO HOLD THE

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