US1863838A - Fuse for antiaircraft projectiles - Google Patents

Description

June 21, 1932. T. B. DOE

FUSE FOR ANTIAIRCRAFT PROJEC'IILES Filed June 6, 1930 2 Sheets-Sheet l' Pagan im 21,1932 i Lemie nnen sfrar s PATENT orriec THOMAS B. DOE,` F NEW YORK, N. Y. l

FUSE `lOIIt ANTIARCRFT POJECTILES Application filed June 6, 1930. Serial No. 459,556.

lThis invention relates to fuses for proj ec-` ploded prematurely.' A further object of tlie tiles, particularly to the type of projectile invention is to so construct the fuse cap that which is detonated at a predetermined point it may be manufactured entirely separately in its flight. Such projectiles are largely from the detonator and other explosive p j employed in antiaircraft gun fire. Usually charges so thatthe fuse may be inanufac- 55 such fuses are operated on the time principle, j tured in any machine shop without danger of the `projectile being detonated `at a predeexplosion. j termined time after it is fired. By my in-` Referring to the drawings showing several iveiition, on the other hand, I propose to repreferred forms of the invention,

l place the costly and delicate timing mecha- Fig. l shows a front elevation of my fuse o0 nisin no w employed by a simple device which Cap ready to be applied to the main shell. depends primarily on the velocity of the pro- Fig. 2 is a vertical section of the same. jectile and isoperated by the pressure of the Fig. 3 is a detail of the hammer which air on the nose thereof which, of course, is a explodes the detonator.

function of the velocity. Since the velocity i Fig. 4 is a vertical section taken at right 65 of the projectile at any given point in its angles to Fig. 2. Y j

flight is a function of the distance of the pro- Fig. 5 is a side elevation of the lowerlporjectile from the gun, it is obvious that the tion of the fuse. i

y air pressure at its forward end at any given Fig. 6 is a vertical section showing a modipoint is also a function of the distance from fied form of fuse. j 7o the gun. o It is, of course, necessary to take Fig. (il-A is an enlarged sectional detail j into account the height of the projectile, atof a portion of the mechanism in Fig. 6 but mospheric conditions, etc., but such factors with the parts shown in a slightly different may all be taken Vinto account in the setting position. v

` of the fuses. The air pressure on the nose of Fig. 7 is an enlarged Sectional detail of a 75 the `projectile may be balanced against any portion of this mechanism,

settable yielding means within the projectile7 Fig. 8 is an enlarged view of the middle such as spring' pressure or the like. I prefer portion of Fig, 6, the parte boing Shown in n to makeuse of the rotation of the projectile different Position,

on its own axis (which is imparted bythe Fig. 9 is a vertical section of a slightly' S0 riiiing in the gun) to create the yielding force modified form of my invention ora pOlOIl thereof WhlCll OlpOSQS lll@ 211 Fig. l0 is a vertical section of a form of pressure, by employing free or partially free the invention using a spring means or a conimasses within the projectile on Which the bination of Spring and Centrifugal moans as Centrifugal foyoo acts, I provide a. .simple the withdrawing forceV for the detent. 85

` and reliable means within the projectile for Fig 11 is a horizontal Section on 1in@ 11- 11 opposing the air pressure means since the ofFig 10,

speed of rotation of the projectile is nearly In the Sectional gnros a, firing pin or a constant quantity, th@ TOUOH defeaslng hammer 1 is shown as slidably mounted in lll VelOClt'y Very Slowly @ncl at a lmOWll l'a'ea transverse bore 2, the hammer being noi- 9o This Celllllfllgal fore@ Wlll Olelclle lll@ inally locked in its mid-position in the bore.

OICG Created by lll@ all' P leSS'lle 011 f1 P01" Said bore preferably extends entirely OD ofthe T1055@ 0l lll@ PlOleClll@ al? Ll Pledfe* through the main body 3 of the nose cap, the lemlled Pollll lll the lllllt 0l lll@ Pl'olecllle Vouter ends of the bore being threaded. Into and iS llgd, when that OCCU'S t0 lllP these ends one or more detonator caps l and 95 a Cletcllt and l'lS@ the 'lllllllfll i 4 may be screwed after the fuse is completely Other ObjeCtS 0f the llVGIl'lOIl 3T@ t0 111 manufactured and ready to be placed on the PI'OVG HP0 fuses 0l the above type by Slllplshell. Said caps communicate with powderfying the same and rendering them absolutetrain channels 5 which lead downwardly ly fool proof `so that the fuse can not be exthrough space 6 and channels 7 into the main 100 Vwhich direction it moves, I provide a be purposely weighted on one side or the` Y other or purposely placed out of the cen-v ter line of the AVshell, since in the ordinary course of manufacture the center of gravity of the same will always be enough out of line with the center of gyration of the shell to l` actua-te the hammer in one direction orthe otherupon its release. In orderethat the hammer may explode the'shellregardless in detonator at each end of the channel. f

This also has the advantage thatthe shell'` may be balanced about its longitudinal axis prior Vto the insertion of the firing pin and this balance will not be materially disturbed by the addition ofthe firingV pin since it need f not be purposely made heavier on oneside in order to insure firing asexplained above.

For normally lockingy the hammer inV place I provide a detent 8 which engages `ln a annular channel in the periphery of the hammer. The hammer as shown in Fig.'v 3 is provided with a passage 10 therethrough so that an air cushion will not be formed as the hammer moves toward one of the detonators. For the same purpose, apertures 0,0 may be provided through the shell for by-pa`ssing the air around the hammer. The detent is preferably arranged to be Withdrawn when'the air pressure at the nose of the projectile falls below a predetermined amount. Y

In order to provide the withdrawing force I also prefer to make vuse. of the rotation of' the shell, the centrifugal force acting on adjustable masses within the nshellto overcome the air pressure and lift the detent. In the form shown in Figs. 6 to 8, which represents the preferred formV of my invention, there is mounted on the stem -8 of the detent a flat triangular shaped member 11. The centrifui gal masses appear in the side elevation as L- shaped members 12-13. 'Each ofsaid members has a flat unitary base 14 which extends under the member 11. 'Ihe upstanding portion of each member, however, isV forked to formtwoA ears 12 and 12, which extend to Y each side of the member 11 (seerFig. 7).

Each centrifugal member is mounted on a base .or plate 16 being normally held in placeV by the pin 17 extending upwardly from the plate and Vfitting loosely in a hole into the base 14. Each plate 16 is'slidably mounted on a slotted member 18 and may be adjusted toward and away from the center of the shell by means ofV a nut 19 threaded on the screw 20. Each nut has a pin 21 extending upwardly therefrom through the slot 22 of member 18Qand which Vextends into a. hole in the plate 16 so that as the Vscrew is turned the plate will be moved toward and away from the center other hand, the corresponding members are` shown as separated somewhat.

Under the action of centrifugal force acting on theupright forked ears 12-12, each member l2-13 will be rotated about its tip end 23r of the base 14 which is shown Las resting in an angle formed by lug 24 at the end of the plate 16 (see Fig. 8). As each memberY rotates about this point it will obviously raise thetriangular member 11 as shown in exaggerated form in Fig. 8, thus withdrawing the detent 8 from the annular .groove in the hammer. It should be noted that the point 23 aboutfwhich each centrifugal member rotates lies in substantially thesame'horizontal plane Y Y as the inner edge 25V of the base 14, or in other words, the line of contact between the base 14 and member 11 as it tilts upwardly. Thisl Yis for the purpose of securing the free disen gagement of base 14 from pin 17 and maxi# mum lifting effect on the member 11 at the start of the outward movementof the centrifugal members 12, 18, .since once the lifting is started it will be continued by the rapid building up of the centrifugal forces due to the outward movement of the tops of the parts 12 and 13. To the same end the base may be longitudinally grooved to lower the member 11 and also hold it in place. In order to maintain this relationship between the toe 23 and the crotch 25, the member 18 is preferably positionedV with its upper surface on la slant as shown. rIhe screw 2O likewise may be shown slanted upwardly although this is not necessary Vas shown in Fig. 9. The adjustment of the screws is simultaneously effected by means "of the range setting ring 26 which extends around the nose cap and is interiorly provided with` teeth 27 meshing with pinions 28-29 on theends respectively of the screws 2020. The 'graduations are read on a reference mark or marks M on a fixed ring 26. The ready 'manner in which the parts maybe assembled and disassembled isY shown in Fig. 5. By unscrewing nose piece 50 and intermediate member`51, the graduated ring 26 and the reference ring 26 may be slipped` off, thus exposing the cross apertures 52, in which are placed the members 18 containing screws 20-20..

While there is no force acting to release the detent until the shell is rotating at high velocity, I prefer to provide an additional safety locking means which I have shown as in the form of fiat springs 30 which are pinned to the interior of the shell and normally lie in grooves 31 in the member 11. said springs lie in said grooves it is obvious that member 11, and hence detent 8,'cannot be As long as moved upwardly.A When, however, the shell j is rapidly rotated, the ends of fiat spring 30, under the action of centrifugal force, move outwardly out of the notches lock the member 11. At `its upper end the stem 8 is provided with a piston-like member 32 shownas threadedon the stem and fitting closely into a bore in the body portion of the nose cap. The top of said pistonis subject to the air pressure,

31 so'as to unj the nose beingprovidedwith an axial bore with a space 38 under the piston. As the projectile rushes through the air, air will'be drawn from the channels 36-37 to create a negative pressure in the space 38 and thus augment the positive pressure on the upper surface of the piston for the purpose specified.

Owing to the fact that during the interval that the shell is being expelled from the gun the air pressure on the nose may not be built up, I prefer to provide an additional safety device for preventing explosion during this interval. This preferably takes the form of a metal ball or equivalent free object which normally lies at the lowest point in the U- shaped channel 34 and has a close but free fit in said channel. It is obvious that when the ball is in the position shown, i. e., with the shell sitting upright on its base that the detent cannot be raised. During the time that the shell is leaving the gun there is enormous acceleration of the shell and the inertia of the ball holds it in its center position in spite of the building up of a high velocity of rotation. This acceleration of the shell continues some distance beyond the muzzle as has been shownexperimentally so that explosion of theshell within the gun orvery close thereto is affectively prevented.

. The form of the invention shown in Figs. 2 and 4l operates on a similar principle to that shown in Figs. 6 and 8. In this form the centrifugal members 12-13 are shown as triangular in shape and rest at their base as before in notched members 41 which are threaded on screws 4:2*l2-l The tops of said members rest against the under-surface of the part 11 secured to the stem 8. Under the action of centrifugal force the tops of the triangular members will be thrown outwardly7 rotating the members about their toes 23 and thus lifting the member 11 and the detent.

j In order `to maintain the proper relationship between the point of lift and the pivotal point of the centrifugal masses 12 and 13, it

vis not necessary to have the screws 20 and i 20 in an inclined position. Fig. 9 shows a construction in which the corresponding screws `90--90 are placed horizontally and the aforesaid proper relationship maintained by making the slide-ways 22', on which the pieces 16 slide7 of triangular shape so that the top surfacethereof presents an inclined surface.` Fig. 9 also illustrates a modified form of locking spring. In this form two springs 91 and 91 are secured adjacent their tops to a Afixed part of the shell with their free ends projecting downwardly to engage a flattened portion 92 on the member 11. The springs may be weighted near their lower ends so that under the action of centrifugal forceV the lower ends will fly outwardly and release the `member 11. Otherwise the action of this form ofthe invention is the same as Fig. 8.

Instead of employing centrifuga-ily operated means as a yielding force to release the detent, I may employ a spring means either with or without centrifugal action. One form of such means is shown in Figs. 1U and 11. In this form of the invention the hainmer 69 is normally maintained `locked in the retracted position by one or more detents or locking pins. One of said pins 70 is a safety catch which prevents al'l possibility of the shell being exploded prematurely. Said detent is on a mass 71 normally held in place by the split ring 72 which lies partly within a recess 7 3 in a nut 74 and partly in an annular recess in the mass 71. When the projectile is discharged from the gun, however, the inertia of said mass 71 is sufficiently great to snap it to the bottom of the bore 75 where it is held by the closure of the ring over the top thereof. The projectile is thus armed andrea-dy to fire upon the release of the main detent or pin 76 from engagement with hammer 69.

Said pin projects downwardly from a stem 77 having a plurality of shoulders and threaded portions thereon. Said stem at its top is flared at 78 to form the nose of the projectile and may also be provided with a slot 7 9 for rotation by a fuse setter. The stein first passes through aA locking ring 80 threaded in the projectile which holds in place a rotatably munted nut or sleeve 81. Said ring is threaded interiorly, preferably with a lefthanded thread, and engages corresponding threads 82 on the stem. Sj'iring-presser locking balls 83 (see Fig. 11) are placed in transverse bores in the shell and engage the exterior of said ring 81. Said balls serve to lock the sleeve 81 against rotation in one direction, i. e., clockwise rotation in Fig. 11, but permit the sleeve to be rotated in the epposite direction.

Secured adjacent the bottom of said stein is a flat coil spring 841-. Said spring is preferably anchored at one end to the stem and at the other end to a pin 85. The spring is normally under more or less tension, i. e., is wound up so that it tends to rotate the stein predetermined range extent.

in a clockwise directionV in Fig.l 11. By turning the stem by means of a screwdriver or fuse setter in a counter-clockwise direction in Fig. 11, the spring will be Wound up for a During such operation, however, theV nut freely rotates with the stem, so that no axial adjustment of the stem takes place.

I also prefer to provide an auxiliary safety device for preventing the spring from prematurely unwinding and releasing the hammer. This device is preferably in the form of a pair of masses 86, each having a projection 87 thereon which engages a collar 88 threaded on stem 77 and having an annular shoulder 89. Said masses are normally pressed into engagement with said collar about said shoulder by springs 9() which press at their outer ends against threaded closures 101. As shown, I prefer to place each of said masses in a bore which extends transversely but at an angle to i a transverse plane passing through the projectile. The centrifugal force tendsto withdraw the masses as soon as the normal speed of `rotation is approached,but due to the forward inclination of the bores in which'they are placed, the centrifugal force is opposed by the inertia of the masses while the projectile is receiving its powerful accelerating impulse from the powder. Therefore, the masses will not be disengaged rfrom the locking collar until the shell is well beyond the muzzle of the gun as in the other forms of the invention. Y 1 Y This formv of the invention is set for range as follows: The parts are assembled in the position shown in Fig. 10, with the detent-76 engaging the hammer 69 and the spring under no or slight tension. The device is then set for range by turning the nose cap. The centrifugal masses 86 donot prevent this since no axialmovement of the pin takes place and the nut 81 has a smooth periphery. This adjustment is effected by turning the stem counter-clockwise or to the left in Fig. 11 so that the nut rotates with the stem and no axial movement takes place. VAfter the shell is fired, however, and the locking pins are all released, the spring will unwind the stem 77 and screw it outwardly thro-ugh the nut81 (which is locked in place against clockwise rotation) as soon as the air pressure on the nose falls below a predetermined amount.

The accuracy of my fuse depends, of course, somewhat on maintaining the muzzle velocity substantially constant. If the muzzle velocity is greater than anticipated, the fuse may be set off prematurely with the centrifugal method, as shown in Figs. 1 to 9 because the velocity of rotation of the shell will be more than correspondingly increased; while if the i muzzle velocity and, therefore, the speed of rotation, is less than anticipated, the fuse will be set off too late. On the other hand, if a spring were employed which was uninfluenced by centrifugal forces, itrwould set 0E the fuse late Vwhere the {muzzleyelocity was greater than anticipated, and early if the muz-V zle velocity 'wereV less than anticipated.V If these two methods arecombined, however, the error due to change in'muzzle velocity may be reduced to a very small amount. The form n of spring shown in Fig. 10 is subject, to a tion of rotation of the shell. `This formof the invention,.therefore, really combines the spring and centrifugal methods and thereby reduces the error referred to. Y

In accordance with the provision of the patent statutes, I have herein described the principle and operation of my invention, to* gether Vwith the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shownis only illustrative and thatJ the invention can be carried` out by other means. Also, while it is designed to'use the various features and elements in the combination and relations described, some of these may be altered and others vomitted without interfcringwith' the more general results outlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure by Letters Patentv 1S: 1 1. In a fuse. for projectiles, the combination with the hammer, of a detent for normally holding said hammer retracted, means subject Vto the air pressure dueto` the flight of the projectile for holding said detent in place, and yielding means opposing said other means for withdrawing said detent when the air pressure becomes a `predetermined amount. Y

2.V In a fuse'for projectiles, the combinationwith the hammer, of a detent for nor- Vmally holding said hammer retracted, means subject to the air pressure due to the flight of the projectile for holding said detent in place, yielding means opposing said other means for withdrawingsaid detent when the air pressure becomes a predetermined amount, a lock for Vpreventing said yielding means from acting before the'projectile has beenA discharged, said loclr being subject to centrifugal force so as to. unlock said means after the projectile is fired.` Y Y 3'. In a fuse for projectiles,-the combination with the firing cap and hammer, of a detent for normally holding said hammer retracted, a movable vmember in the nose of said projectile and/connected to said detent for holding it in place, and settable yielding means for withdrawingfsaid detent when the `pressure on the nose falls below a predei tent, the release -of said locking means, in

turn, being opposed by acceleration forces whilethe projectile is leaving the gun.

.l 5. In a fuse forprojectiles, the combination with the hammer, of al detent for normally holding said hammerretracted, means subject to the air pressure Jdue to the flight of the `projectile for holding said, detent in place, movable masses within the projectile subject to the centrifugal force created by the rotation thereof for withdrawing said detent when the air pressure becomes al predetermined` amount,` and settable means for varying the effective force exerted by `said masses on said detent for varying the range at which the shell explodes.

. 6. Ina fuse for projectiles, the combination `with the hammer, of a detent for normally holding said hammer retracted, yielding means tending to withdraw said detent comprising a pair of centrifugal members pivoted on opposite sides of said detent and adapted under the action of centrifugal forces, due to rotation of the projectile, to rotate'outwardly and lift said detent, means for adjusting said masses toward and away from the axis of the projectile to vary the range, and means responsive to air pressure of opposing said withdrawingr force.

7 In a fuse for projectiles, the combination with the hammer, of a detent for normally holding said hammer retracted, yielding means tending to withdraw said detent comprising a pair of centrifugal members pivoted on opposite sides of said detent and `adapted under the action of centrifugal forces, due to rotation of the projectile, to

.rotate outwardly and lift said detent, and

means responsive to air pressure for opposing said withdrawing force.

8. ln a fuse for projectiles, the combination with the hammer, of a detent for normally holding said hammer retracted, cen- `trifugally operated means for withdrawing said detent comprising a member mounted f to one side of the axis of the projectile to pivot about the outer edge of its base under the action of centrifugal force and to raise said detent when so rotated, settable means for varying the distance of said member from the axis of said projectile to vary the range,

a and means for exerting an opposing force to the centrifugal action of said member on said detent.

9. In a fuse for projectiles, the combination with the hammer, of a detent for normally holding said hammer retracted, means subject to the air pressure due to the flight of the projectile for holding said detent in place, movable masses within the projectile subject to the centrifugal force created by the rotation thereof for withdrawing said detent when the air pressure becomes a predetermined amount, settable means for varying the eli'ective force exerted bynsaid masses on said detent for varying the range at which the shell explodes, and inertia operated safety locking means for preventing withdrawal of said detent until the projectile has left the gun.

10. In a fuse for projectiles, the combination with the hammer, of a detent for normally holding said hammer retracted, means subject to the air pressure due to the flight of the projectile for holding said detent in place, and combined spring and centrifugal means for withdrawing said detent when the air pressure falls below a predetermined amount.

11. In a fuse for projectiles, the combination with the liring cap and hammer, of a detent' for normally holding said hammer retracted, avmovable nose on said projectile connected to said detent for holding it in place, and `settable spring means also subject to centrifugal forces for withdrawing said detent when the pressure on the nose falls below a predetermined amount.

12. In a fuse for shells,\the combination with the firing pin and locking detent, of centrifugally operated mea-ns for withdrawing said detentcomprising an L-shaped member adapted to pivot about its outer edge under the action of centrifugal force on its top, said` pivoting edge being substantially on a line with the point of lift of said member on said detent. V

13.1n an air pressure fuse for projectiles, a detent for locking the firing pin, centrifugal means for` withdrawing said detent, a centrifugally released spring lock for preventingaccidental withdrawal of said detent, and

an additionalmeans for preventing explosion- 15. ln an air pressure. fuse for projectiles, a detent for locking the firing pin, centrifugal means for withdrawing said detent, a centrifugally released spring lock for preventing accidental withdrawal of said detent, and means for preventing explosion in the gun barrel comprising a ball in a U-shaped channel disposed across the axis of the shell above said detent and adapted to prevent withdrawal of said detent while it lies near the bottom of said channel.

16. A fuse .for projectiles, in combination with a nose cap, of a cross channel therethrough, a substantially symmetrical Yfiring pin normally held therein at about the longitudinal axisof the projectile, and a percussion'cap holder adapted to be detachably secured in each end of said cross channel whereby the shell is not materially unbalanced about its longitudinal axis by said firing pin.

17. A fuse for projectiles, in Combination with a hammer, of a detent for normally holding said hammer retracted, a piston member connected to said detent for holding the same in place, the upper surface of said piston being subject to the air pressure at the nose' of the projectile, and rearwardly inclinedl channelsin said projectile leading to the under-surface of said piston whereby a negative pressure is created thereon, and yielding means for opposing said piston for firing the projectile when the effective pressurev on the piston falls below a predetermined amount.

18. In a fuse for projectiles, the combination with the Vfiring pin and locking detent, of means for withdrawing said detent, at a predetermined point in the flight of the shell, and a safety lock for preventingpremature release in the gun barrel comprising a U- Y shaped channel extending across the axis of the shell and above said detent, and aball in said channel whereby inertia holds the ball over the detent during acceleration of the shell but centrifugal force displaces it as acceleration ceases.

19. In an air pressure fuse for projectiles,

a detent for locking the firing pin, centrifugal means for withdrawing said detent, and means for preventing explosion in the gun barrel comprising a ball in aY U-shaped channel disposed across the axis of the shell above said detent and adaptedvto prevent with'-V drawal of said detentY while it lies near the bottom of said channel whereby. inertia holds f an inertia lock subject both to opposed transprevents lifting of said detent as long as the ball remains in the cup. l j l 22.111 a safety fuse for projectiles, the combination with the firing pin and locking detent, of means for preventing premature release of the detent including a cup on the detent, and a ball in said cup and normally held therein by gravity with the shell sitting on its base and by inertia during the acceleration of the shell in the gun barrel but expelled therefrom by centrifugal force as ac-` celeration ceases.

In testimony whereof I have aflixed my signature.

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