US 3722419 A
The arming device includes an unbalanced rotor adapted for movement in response to acceleration forces between a first missile unarmed position and a second missile armed position. A setback weight locks the rotor in the first position and is responsive to acceleration forces to release the rotor for movement into the second position. A detent movable in a direction normal to the plane of the rotor engages the rotor in the second position to lock it in the armed position. A second detent carried by the setback weight is movable in a direction parallel to the plane containing the rotor to engage the rotor in the second position in response to deceleration forces and the bias of springs tending to return the weight to its initial rotor locking position.
Description (OCR text may contain errors)
[451 Mar. 27,1973
 ll G DEVICE FOR MISSILES  Inventor: John 0. James, Lancaster, Pa.
 Assignee: HMW Industries, Inc., Lancaster,
 Filed: May 6, 1971  Appl. No.: 140,849
 US. Cl ..102/78, 102/76  Int. Cl. ..F42c 15/24  Field of Search ..102/78, 79, 80, 76, 70
 References Cited UNITED STATES PATENTS 2,537,953 1/1951 2,948,219 8/1960 2,993,442 7/ 1961 3,117,522 l/1964 Hutchison et al. ..102/78 Primary Examiner-Samuel W. Engle Attorney-LeBlanc & Shur 571' ABSTRACT The arming device includes an unbalanced rotor adapted for movement in response to acceleration forces between a first missile unarmed position and a second missile armed position. A setback weight locks the rotor in the first position and is responsive to acceleration forces to release the rotor for movement into the second position. A detent movable in a direction normal to the plane of the rotor engages the rotor in the second position to lock it in the armed position. A second detent carried by the setback weight is movable in a direction parallel to the plane containing the rotor to engage the rotor in the second position in response to deceleration forces and the bias of springs tending to return the weight to its initial rotor locking position.
1Claim,9DrawingFigm-es V PATEPUF'QHARZYKGTZ 722 419 JOHN 0. JAMES INVENTOR BY 51M; 941/ ATTORNEYS ARMING DEVICE FOR MISSILES The present invention relates to arming devices for missiles and the like and more particularly to a novel and improved fuze for use in rockets.
The invention hereof relates to an improvement in the rocket fuze described and illustrated in US. Pat. No. 2.948,2l9. In that patent, there is disclosed a rocket fuze comprised of a rotor movable under acceleration forces from an initial position wherein a pyrotechnic train through the rotor is misaligned with the firing pin and booster charge to a rocket armed position wherein the pyrotechnic train lies in alignment with the arming pin and booster charge. A setback' weight locks the rotor in its first rocket unarmed position and releases it in response to acceleration forces for movement into the second rocket anned position. The setback weight maintains a continuous bias on the rotor tending to maintain it in the first rocket unarmed position. This precludes movement of the rotor into the rocket armed position in response to spurious forces. The rotor is locked in the rocket armed position by a spring biased detent which is received within a recess formed in the face of the rotor when the latter obtains the armed position. Under normal circumstances, the mechanism for detenting the rotor in the second rocket armed position is satisfactory. However, it has been found, where the rocket is employed in an environment wherein it must penetrate an object several feet prior to detonation, for example, a log bunker wall, that transient shocks or random force vectors tend to unlock the detenting pin, freeing the rotor for rotation from the armed position back to the unarmed position under the spring bias. Consequently, such transient shocks or random force vectors defeat the detent with the result that the rocket warhead cannot detonate.
It is therefore a primary object of the present invention to provide a novel and improved detenting system for a rocket fuze which is substantially nonresponsive to transient shocks and random force vectors when in the armed condition and will maintain the fuze in the armed condition notwithstanding such forces and shocks.
It is another object of the present invention to provide a detenting system for an arming device in a mis-' sile wherein a pair of non-parallel acting detents are provided whereby the probability of a force or shock defeating both detents simultaneously is virtually nonexistent.
It is still another object of the present invention to provide an improved and novel detenting system for the rocket fuze disclosed in the aforementioned U.S. Pat. No. 2,948,219, and which is simple and inexpensive in construction and does not significantly alter the design of the existing fuze.
These and further objects and advantages of the present invention will become more apparent upon reference to the following specification, appended claims and drawings wherein:
FIG. 1 is a longitudinal axial section through the nose of a rocket illustrating a fuze constructedv in accordance with the present invention;
FIG. 2 is an enlarged side elevational view of the fuze employed in the arming device of FIG. 1, the fuze being illustrated in an unarmed condition;
FIG. 3 is an enlarged side elevational view of the fuze illustratedin FIG. 2 viewing the fuze from left to right in FIG. 2;
FIGS. 4a, 5a, and 6a are schematic side elevational viewsof the fuze illustrating movement of the rotor and setback weight in various positions of the arming cycle; and
FIGS. 4b, 5b, and 6b are cross sectional views through the plane of the rotor looking toward the setback weight and illustrating the dual detenting mechanism hereof, the rotor positions of FIGS. 4b, 5b, and 6b corresponding to the rotor positions of FIGS. 4a, 5a, and 6a respectively.
Referring now to the drawings, particularly to FIG. 1, there is disclosed an arming device 10 for a rocket and the like including a body 12 having a hammer 14 and a secondary hammer 16 slidably carried by housing 12. The hammer 16 carries a stab type firing pin 17. This subassembly is slidably carried by a sleeve 18 and is restrained from rearward axial movement due to acceleration of the rocket by an anti-setback washer 20 retained against the rear end of sleeve 18 by a nut 22 threadedly engaging the fuze body. A deformable closure 24 covers the forward end of the hammer and, upon impact with the target, closure 24 is deformed rearwardly driving hammer 14 against secondary hammer 16 which, in turn, is driven through the antisetback washer 20 with pin 17 firing the pyrotechnic train in the rotor R. Rotor R forms a part of a fuze F of the arming device 10 and is mounted for rotation between a rocket unarmed position illustrated in FIGS. 1-3 and a rocket armed position illustrated in FIGS. 6a and 6b, the rotor containing the pyrotechnic train, not shown, in a diametrical passage 26 therethrough. The passage is, in the unarmed position, misaligned with firing pin 17 and a lead-in 28 of a booster charge 30, the latter being utilized to detonate the main charge, not shown, carried by the rocket.
Fuze F is fully disclosed in US. Pat. No. 2.948,2l9 with the exception of the apparatus providing a double detenting action in the armed position of the rotor. The disclosure of US. Pat. No. 2,948,219 is accordingly incorporated herein by reference thereto as though fully set forth herein. Since the operation of the fuze is fully disclosed in that patent with the exception of the double detenting action, detailed disclosure of the fuze is not herein presented. It is believed sufficient for present purposes to note that the fuze includes a metal frame 44 including a base 46 and a pair of legs 48. A runaway escapement mechanism, generally indicated 49, is disposed between a pair of upright plates 52 and 54 on one side of frame 44 and rotor R is journalled for rotation between leg 48 and side plate 52. The rotor is circular in shape having a cutout along a chord line 66, the flat side 66 of rotor R, in the unarmed position, bearing against a pin, not shown, projecting inwardly from plate 52. The rotor includes a roller carried on one side thereof and a circular gear segment 129 which engages with a pinion gear 132 for driving the escapement. A U-shaped setback weight 88 is mounted on a pair of pins 76 and 78 about which are received springs 84 and 86 respectively.
It will be appreciated from a review of US. Pat. No. 2,948,219 that setback weight 88 moves from the position illustrated in FIGS. 2 and 3 in response to initial acceleration and against the bias of springs 84 and 86 to a position illustrated in FIGS. 4a and 5a. Movement of weight 88 releases rotor R for rotation in the direction of the arrow in FIG. 4a under the control of escapement 49. Sustained acceleration moves rotor R to the position illustrated in FIG. 4a and 5b whereupon a spring biased detent 114 carried by mounting plates 52 and 54 engages in an aperture 120 formed on the face of rotor R locking the rotor in the armed position illustrated in FIGS. 5a and 5b.
It has been found, however, that random forces applied to the rocket, for example, as it penetrates a thick walled bunker, may have the effect of moving detent 114 from engagement within recess 120 with the result that the springs 84 and 86 biasing setback weight 88 back to the position illustrated in FIG. 2 and which bias also operates to rotate rotor R through the engagement of weight 88 with roller 100 on rotor R back to the missile unarmed position illustrated in FIG. 2. This would rotate the pyrotechnic train in diametrical passage 26 out of alignment with the firing pin and lead-in 28 resulting in a dud.
To preclude these spurious forces from unlocking the fuze from its armed position prior to detonation, there is provided, in accordance with the present invention, a second detent which is responsive to deceleration forces acting on the rocket. Particularly, rotor R is provided with a peripheral recess or notch 150 ad- .jacent the chordal portion 66 thereof, the periphery of the rotor between notch 150 and chordal portion 66 being cut away to form a short peripheral portion 152 of reduced radius. A secondary detent or pin 154 is provided the lower inside face of setback weight 88 and projects toward rotor R. In the unarmed position of the fuze, the pin 154 underlies chordal portion 66 of rotor R. When setback weight 88 moves in response to acceleration forces to the position illustrated in FIGS. 40 and 5a, pin 154 lies radially beyond peripheral portion 152 of rotor R whereby the rotor, when it swings to the armed position as illustrated in FIG. 5b, brings notch 150 into vertical alignment with pin 154. When the acceleration forces become zero or very nearly zero as when the rocket burns out and a slight deceleration is caused by the skin friction as the projectile moves through the air, the setback weight moves forward under the influence of springs 84 and 86 to inject locking pin 154 into notch 150 thereby providing a second detent for rotor R. When the rocket impacts the target, the deceleration forces increase within a relatively short period of time causing the setback weight to press the locking pin progressively tighter into notch 150. The upper edge of one of the legs of U-shaped setback weight 88 is provided with arcuately shaped relief notch 160 corresponding to the surface of roller 100. The depth of the relief notch 160 permits only limited forward travel of setback weight 88. Thus, when setback weight 88 moves forwardly under the deceleration forces, a potion of roller 100 engages in the relief notch preventing the locking pin 154 from being sheared off during impact.
Alternatively, the height of setback weight 88 can be reduced a distance equal to the depth of notch 160. It is important that the rotor have the capability of returning to the safe position in the event that acceleration ceases prior to arming. Thus, a smooth upper surface on setback weight 88 can be provided to more effectively cam the rotor back to the safe position.
It will be appreciated that the directions of movement of pin 114 and setback weight 88 are erpendicular one to the other. That IS to say, pm 11 IS mounted for movement in a direction normal to the plane containing rotor R, whereas pin 154 is mounted for movement in a direction parallel to the plane containing rotor R. Consequently, the likelihood of spurious forces acting on the rocket upon impact tending to defeat both detenting pin 114 and pin 154, Le, remove them from detenting positions, is remote.
The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
What is claimed and desired to be secured by United States Letters Patent is:
1. In an arming device for a missile comprising a firing device and a booster charge, an unbalanced rotor mounted between said firing device and said booster charge for rotation in response to missile acceleration forces from an unarmed position to an armed position, said rotor having a passage therethrough from edge to edge in the plane containing said rotor and having a pyrotechnic train therein, said rotor in the unarmed and armed positions having said passage respectively misaligned and aligned between said firing device and said booster charge, means for releasably locking said rotor in said unarmed position against movement in both rotary directions and including a weight movable between rotor locking and unlocking positions in response to acceleration forces, means for normally maintaining said weight in said rotor locking position including a spring biasing said weight for movement into said rotor locking position, and means including first and second detents movable along paths respectively generally normal and parallel to the plane containing said rotor into engagement with said rotor for locking said rotor in said armed position, said rotor having a notch opening through its periphery, said weight carrying one of said detents, the detent carried by said weight being receivable in said notch in response to missile deceleration forces, and means on said rotor in the armed position thereof and engageable with said weight for arresting movement of said weight under the bias of said spring in a direction toward its rotor locking position.