US 3211099 A
Description (OCR text may contain errors)
Oct. 12, 1965 D. POPOVITCH 3,211,099
TIME DELAY MECHANISM Filed 001,- 51, 1963 I r 31 H 3o\ 32 '2 g l I FIG.2. 9 X
26 101 X 24 l Ig (.p I
' Y PROJECTILE SPIN AXIS IN VEN TOR. DRAGOLYOUB POPOVITCH United States Patent 3,211,099 TIME DELAY MECHANISM Dragolyoub Popovitch, Lake Parsippany, N .J assignor to the United States of America as represented by the Secretary of the Army Filed Oct. 31, 1963, Ser. No. 320,581 Claims. '(Cl. 102-79) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.
The present invention relates to time fuzes for relatively-small-diameter artillery and other ammunition, and more particularly to mechanisms for effecting a predetermined time delay in the operation of such fuzes in projectiles of the type referred to.
It is an object of the present invention to provide an improved time-delay mechanism for artillery and like projectiles of relatively small diameter that can be adapted to a limited space requirement and operate more safely and effectively.
A time delay, as is understood, is required to prevent a projectile from firing or detonating in the gun tube or barrel and also for a safe distance beyond the gun position. The problem is to insure such time delay for ammunition of small diameter where allowable space for the time delay mechanism is limited both by the inside and the outside diameters of the whole fuze, compatible with the small caliber of the projectile.
It is a further object of the invention to provide an improved fuze timing mechanism adapted for use with a ball-type rotor, containing the detonator, of a fixed diameter while retaining a fixed and relatively-small outside fuze diameter and a desired degree of compactness.
In accordance with one form of the invention, a hollow ball rotor in a fuze is subjected to a predetermined braking torque by a helical-type spring element adjustably tightened into frictional engagement as a wrapping about the diameter. This reduces the angular velocity of the ball rotor in aligning its axis of symmetry in flight with the spin axis of the round or projectile in which it is mounted. The time required for the rotor to do this is the time delay.
Prior designs developed to insure a required time delay for a fuze using a ball type rotor element of fixed diameter did not attain the desired fixed and relatively-small outside diameter of the body, and thus, the desired compactness of construction. The use of ball bearings around the rotor, to minimize friction between the fuze body and the rotor, required more space than was readily available. There was no control of the friction, and hence, of the force due to the spin transmitted from the body to the rotor for its alignment with the spin axis. A time delay mechanism in accordance with the invention overcomes these and other problems.
The invention will, however, be further understood from the following description of a specific embodiment thereof, when considered with reference to the accompanying drawing, and its scope is pointed out in the appended claims.
In the drawing,
FIG. 1 is a top view of a fuze, for use with an artillery shell or like projectile of relatively small diameter, embodying the invention, and
FIG. 2 is a sectional view, in elevation, of the fuze of FIG. 1, showing further details of construction in accordance with the invention.
Referring to the drawing, the fuze structure comprises a ball rotor or rotor element 5 within a housing assembly comprising a main cylindrical body 6 and an end cap or closure element 7 fitted into the hollow central end open- 3,211,099 Patented Oct. 12, 1965 ing' or socket 8 therein for the rotor. Both the cap 7 and body 6 are provided with bearing surfaces 9 and 10 for the rotor. The body 6 thus provides a seat for the rotor in which it is retained by the cap 7. The cap is provided with a closure plate 11 having a central opening 12 and has a tight frictional fit with the cap 7. An outer cover element 14 fits over the cap as indicated.
A helical 'timing control spring 16 of a few turns or convolutions is affixed or connected at one end to the main body in a suitable locking hole 17 and at the other end to the cap 7 in a similar hole 18. It encircles the rotor on a diametral line and frictionally engages the outer surface thereof. A set of predetermined tool holes 20 and 21 are located in the peripheral surface portions of the rotor on opposite sides of a firing or locking-pin hole 22 which is alignable with the longitudinal axis YY of the housing assembly. The holes 20 and 21 are used in measuring the torque or braking action applied by the spring when tightened or loosened by turning the end cap 7.
The rotor is provided with a hollow interior in the form of a tubular opening or passageway 23 extending therethrough diametrically on an axis XX. This is the axis of symmetry of its mass or body and is normally set at a predetermined angle, as indicated, with respect to the longitudinal axis YY of the fuze. The passageway is adapted to contain the fuze detonator which may fire after it is aligned with the axis YY and in communication with an opening 24 for a chamber 25 in the body of the fuze. An additional set of holes 20', 21' and 22 in the rotor surface on the opposite side of the axis XX from the holes 20, 21 and 22 are provided to maintain the symmetry of the rotor about said axis.
The axis YY is aligned with and is the same as the spin axis of the whole projectile with which the fuze is connected, as indicated in outline at 26. The rotor is locked in the safety position shown, with the axis of symmetry XX and the passageway 23 at the predetermined angle to the spin axis Y-Y, by a locking or firing pin 27 which seats in or engages the locking hole 22 and extends through the coverplate opening 12 and a bearing bracket 28 on the plate, with a free sliding fit. A biasing spring 29 of the coiled compression type surrounds the firing pin 27 between the coverplate 11 and a stake or through-pin 30 extending transversely of or diametrically through the pin 27. This is in latching engagement with and forms part of centrifugally-actuated or spin-responsive release means for the firing pin including and indicated by fly weights 31 and 32 which move in the direction of the arrows by centrifugal force and clear the stake or latch element 30 when the projectile is fired or launched and attains full rotational speed about the spin axis YY. This unlatches the stake or latch element 30 and the firing pin 27. The latter is then free to move under spring bias to disengage from the locking hole 22 and unlock the rotor. As any suitable spin-responsive latching or locking means for the rotor may be provided further description is not believed to be necessary.
When the projectile is fired and has attained full rotational speed it is safely clear of the gun site before it is fully armed after unlocking the rotor, due to a delay action imparted to the rotor. When in flight, the fuze structure rotates about the axis YY and the ball rotor is forced by centrifugal action on the mass centers thereof to turn about an axis perpendicular to the plane of the drawing as viewed in FIG. 2 until its axis of symmetry XX coincides with the spin axis YY. After unlocking, the time delay in doing this is a function of the braking torque applied by the control spring 16. This, in turn, is adjusted by rotation of the end cap 7 as described, and can be set with a high degree of accuracy at the time of manufacture so that only slight changes are needed at any later time for a predetermined desired delay time. This relation can be established by appropri ate tests and thus can be used for manufacturing purposes. The influence of manufacturing tolerances and quality of finishes in the bearing surfaces and the like, can be compensated to achieve a more uniform time delay in the production run of such devices. The device may thus be armed in flight with any desired and accurate margin of safety for firing on impact, as the firing pin, time-delayed into alignment therewith, is driven back or otherwise made to strike the detonating charge.
From the foregoing description it will be seen that the problem of providing accurate and effective time delay action in fuzes for ammunition involving projectiles of small diameter is met in accordance with the invention by a simplified construction. In this a ball rotor containing the detonator is set and locked with its axis of symmetry at an angle to the spin axis of the projectile with which the time delay mechanism is used. The rotor is unlocked and is then subjected to a predetermined braking torque by a coiled spring element wrapped and tightened around the rotor to reduce its angular velocity in turning and aligning its axis of symmetry with the spin axis of the round or projectile before detonating.
1. A time-delay mechanism for artillery fuzes and the like, comprising in combination, a ball rotor adapted to receive a detonating charge and having a predetermined axis of mass symmetry, a cylindrical body element, means in said body element providing a seat for said rotor, a rotatable end cap mounted on said body and providing a retaining means for said rotor, means for mounting said body with the longitudinal axis thereof along and coextensive with the spin axis of a projectile in flight, and means including a coiled spring surrounding and directly frictionally engaging a surface of said rotor along a diametral line for subjecting said rotor to a braking torque and a timing delay in moving to bring said rotor into a firing position for said charge and said axis of symmetry into alignment with the spin axis from a fixed angular safety position with respect thereto.
2. A time-delay mechanism as defined in claim 1, wherein the spring is connected at one end with the body and at the other end to the rotatable end cap, thereby to vary the tension on the spring and the timing delay by rotation of said end cap.
3. A time-delay mechanism as defined in claim 2, wherein the ball rotor is provided with a passageway therein extending along said axis of symmetry for receiving and holding said detonating charge, and wherein a firing pin element is positioned in said body and adapted to move axially to release said rotor from said fixed angular position in response to a stable rotational speed of said body element and to fire said charge on impact and following said time delay.
4. A time-delay mechanism for artillery fuzes and ammunition of relatively small diameter comprising in combination, a ball rotor having an open passageway extending therethrough along an axis of symmetry therefor, said passageway being adapted to receive and hold a detonating charge, a cylindrical fuze body having an end opening therein and providing a seat for said rotor, a cap element providing an end closure means for said opening and retaining means for said rotor, means for mounting said body with the logitudinal axis thereof aligned With the spin axis of a projectile with the fuze body attached thereto, said cap element and body being frictiona'lly connected and relatively rotatable about said spin axis, a helical-type control spring surrounding the rotor and directly frictionally engaging a portion of the outer surface thereof along a diametral line spin-releasable means for holding said rotor with said axis of symmetry at a predetermined angle with respect to the spin axis and the longitudinal axis of the body, and means providing end connections for the spring with said body and cap element, whereby relative rotational movement thereof changes the tension of said spring and frictional timing control of rotor movement in response to spin of said body and alignment of said axes one with the other upon release of said rotor for fuze detonation.
5. A time-delay mechanism for artillery fuzes and the like, comprising in combination, a ball rotor having an open-ended passageway therein extending along an axis of symmetry of said rotor, said passageway being adapted to receive and hold a detonating charge, a cylindrical body having an end opening and means therein providing a seat for said rotor, a rotatable end cap for said body providing a closure means for said opening and retaining means for said rotor, means for mounting said body with the longitudinal axis thereof along and coextensive with the spin axis of a projectile fuze, a coiled spring element surrounding the ball rotor and directly frictionally engaging a portion of the outer surface thereof, spin releasable means for holding said rotor with the axis of symmetry at a predetermined angle With respect to the longitudinal axis of said body and the spin axis, and means providing end connections for said spring element with the body and the cap, whereby relative rotational movement thereof changes the spring tension and frictional timing control of rotor movement in response to spin of said body and alignment of said axes one with the other for fuze detonation.
References Cited by the Examiner UNITED STATES PATENTS 2,663,260 12/53 Thompson 102-73 2,921,527 1/60 Guerne l0979 2,924,176 2/60 Neuwirth et a1. 10279 X 2,978,982 4/61 Bianchi 10279 SAMUEL FEINBERG, Primary Examiner.
BENJAMIN A. BORCHELT, Examiner,