US1772613A - Projectile fuse - Google Patents

Description

g 12, 1930- c. a. MELLSTROM 1,772,513 I PRQJECTILE FUSE Filed April'fi, 1928 Patented Aug. 12, 1930 I UNITED STATES,

PATENT OFFICE CHARLES GUSTAV MELLSTROM, OF WESTMINSTER, LONDON, ENGLAND, ASSIGNOR TO VICKERS LIMITED, OF LONDON, ENGLAND, A BRITISH COMPANY PROJECTILE FUSE Application filed April 5, 1928, Serial No. 267,511, and in Great Britain May 7, 1927.

' This invention relates to projectile fuses and has for its chief object to devise an improved fuse which will operate satisfactorily on graze aswell as on impact. u 7

According to the invention a spring controlled firing element is normally held inits retracted position by a retaining member which is so constructed and arranged that when the spin of the projectile is'retarded as a result of the projectile grazing an object, the rotational inertia of the said member will cause it to move into the releasing position to enable the firing element to operate. This retaining member may be in the form of a pivoted arm the pivot of which is parallel to and at one side of the axis of the fuse and the portion of the arm opposite the said pivot is weighted to such an extent that when the spin of the projectile is normal and unchanging, or'is only changing slowly, there is a centrifugal bias tending to'keep the said arm in its retaining position, the amount of centrifugal bias in this direction being kept as low as is practicable. The said arm may also be positively locked in this position, until the projectile has been fired from the'gun by a centrifugal, locking bolt which in turn is held in the locking positionby an inertia det'ent. On shock of discharge this detent moves're'arwards against the resistance of a springand the'spin of the projectile then causes the locking bolt to move into the releasing position; WVhen the forward acceleration of the projectile ceases the detent is returned by its spring and passes in front of the inner portion of the centrifugal locking bolt an'dthus prevents'thelatter from'returning to its lockingposition, I

The otherfiring element (i. e. that for 00- operating 'withthe firing element normally held in the retracted position by the retaining member) may be carried by a block or pellet which on impact (as distinct from a mere graze) of theproje'ctilewith an obstruc-' -tion,-moves forward'by its mome'ntum to fire the detonator cap carried by one of the said firing elementsa In orderzthatgthe said invention may; be

clearly understoodand readily carried into eifect,the same will nowbe described more fully with reference to the accompanying drawings in which a v Figure 1 is a side elevation of a fuse in accordance with this invention.

Figure 2 is an axial section of the fuse, Y

Figure 3 is a section taken approximately on'the line 3, 3 of Figure 2,

Figure 4 is a plan on a larger scale than Figures 1 to 3, of the firing element that moves forward by momentum on impact, the

1fairing needle being in the unarmed condi- Figure 5 is a section taken approximately on the line 5, 5 of Figure 4,

Figure 6 is a section taken approximately on the line 6, 6 of Figure 5, and

Figures 7 and 8 are views similar to Figures 5 and 6 showing the firing needle in the armed condition.

A is the fuse body provided with a screwed collar A which receives a cap A at its outer end. B is the detonator cap holder (constituting one of the firing elements of the fuse) slidably disposed in an axial recess in the col lar A Between this holder and the cap A is arranged a helical spring B which, when the holder is released as will be described hereinafter, impels the said holder rearwards to explode the detonator cap B In the par ticular construction shown the other firing element is of known type and comprises a block or pellet C which is slidably mounted in an axial recess in the rear part of the fuse body and carries a needle member C pivoted at C" and normally held in a safe position with the needle C out of line with the deto nator cap B by centrifugal locking bolts C C These locking bolts are moved outwards into their releasingposition (Figurei8) as a result of the spin of the projectile andithe member C carrying the firing needle C is so constructed that when released it moves under the action of centrifugal force from its housed position (Figures lto 6) into a position to bring the needle'in line with the detonator cap (Figures 7 and 8). 'The block or pellet O carries forwardly extending spring plungers C which prevent forward creeping movement of the block or pellet, When however the shell strikes (as distinct from merely grazing) an obstruction the block or pellet C moves in a forward direction by momentum to bring the firing needle G into contact with the detonator cap B The detonator cap holder B is also at the same time released as will be described owing, to the cessation of the spin of theprojectile, but the firing of the detonator cap on impact of the projectile with an obstruction is not dependent upon the release of'the detenator cap holder.

D is the aforesaid retaining member for normally holding the spring controlled detonator cap holder B in the retracted position shown in Figure 2. This member is in the form of an arm of curved formation (see Figure 3) pivoted to the fuse body by means of a pin. D arranged parallel to andat one side of the axis of the fuse. The middle'pore tion of thesaid arm engages beneath. a shoulder B on the detonator cap. holder B as shewn in Fi ure 2 and the portion of the said arm opposite the pivot pin D is enlarged as shown so that the centre of mass, of the said arm D is situated; on that side of a plane passing through the axis of the pivot pin D and the axis of the fuse, which approaches a stop D (as indicated by the dotted line in Figure 3) such that when the spin ofthe projectile is normal; and unchanging (or only changing slowly) the effect of centrifugal force is to tend toturnthe arm D about the pivot pin D in a clockwise direction in Figure 3- and therefore to hold the said arm inits retaining position. This action is assisted by a small leg spring D It will: be seen that the arm D is. arranged at the side of the holder D such that when spin is imparted to the projectile by the riliing of the gun barrel, the inertia of the said arm holds the latter iii-the retaining position in contact withthe stop 13* (Figure 3) The said arm is positively locked in the retaining position, until the projectile has been fired from the gun, by a centrifugal locking bolt E which is disposed in. a recess in a plug E in the side of'the fuse body and engages in a hole in the foresaid enlarged portion of the arm D. This locking bolt is normally locked in its engaging position by a longitudinally arranged and spring controlled inertia'detent'E @n shoclrof discharge this detentmoves rearwards and unlocks the bolt E which then moves outwards under the action of the spin of'the projectile tounlock the arm lVhen the forward acceleration of the Projectile ceases the-spring of the'detent E returns the lattersothat it is situated" at theinner' side ef the: bolt 11 and the latter is thereby prevented from returnin to its locking posirection (Figure 3) b:y-"reason of-its-rotatiional inertia, thereby releasing the detonator cap holder B which is thereupon impelled by its spring B to bring the detonator cap B into forcible contact with the firing needle C which has already moved into the position shown in Figures 7 and 8 previously de scribed.

Although the needle member C has been described as being carried by a block or pellet C which, onimpact of the projectile with an obstruction, moves forwardly to bring the needle against the detonator cap B the said needle member can be carried by a fixed part in which case the stoppage of the spin of the projectile on impactis relied upon to release the detonator cap holder 3. as has been described above in regard to what occurs when the projectile grazes an object.

WVhat I claim and desire to; secure by Let-. ters Patent of the United States 1551- 1. In a projectile fuse the combination with a spring controlled firing element, of a retaining member for said element, and means for mounting said member so that it moves in a plane transverse to t he longitudinal axis of the fuse, by rotational inertia when the spin of the projectile is retarded as a result of'the projectile grazingan object, and means whereby the movement. of said member by rotational inertia releases said firing element.

2; In aprojectile fuse the combination with a'spring controlled firing element, of aretaining member for said element, and means for rotatably mounting said member so that it moves angularly in aplane transverse to the longitudinal axis of the fuse, by rotational inertia when the spin of the projectile is re:- tarded as a result of the projectile. grazing an object, andmeans whereby the movement of said member by rotational inertia'releases said firing element. j

3. In a projectile fuse the combination with a spring controlled firing element, of a re.- taining arm for said element and means; for pivoting said armso. that it turns about an axis parallel to the longitudinal axis of the fuse, into its releasingposition, by rotational inertia. when the spin of the projectile is retarded asa result of the projectile grazing an object.

. l. In a projectile fuse, the combination with the elementsv claimed in; claim 3, of means forweighting the, portion O f the arm opposite its: pivot to such anextent thatwhen the spin of the projectile is normal changing or. is only changing slowly-, there is centrifugal bias tendingto keep-the'said arm in its retaining. positiorn 5. In a projectile fuse, the. cgrnblnatign with. the; elements claimed'ian claim-13; ofi'a centrifugal locking bolt which; engages? the retaining member to. lock it inthe retainposition until'sai dliboltis moved by censtrifugalforcetto the disengaging position,

Bill

6. In a projectile fuse, the combination with the elements claimed in claim 3, of a centrifugal locking bolt which engages with the retaining member to lock it in the retaining position until said bolt is moved by centrifugal force to the disengaging position and an inertia detent normally holding the locking bolt in the locking position.

7. In a projectile fuse, the combination with the elements claimed in claim 3, of a centrifugal locking bolt which engages with the retaining member to lock it in the retaining position until said bolt is moved by centrifugal force to the disengaging position, an inertia detent normally holding the locking bolt in the locking position, and a spring which, after the forward acceleration of the projectile ceases, moves said detent into a position in front of said locking bolt so as to revent the latter from returning to its locklng position.

8. In a projectile fuse, the combination with the elements claimed in claim 1, of a second firing element carried by a member which on impact (as distinct from a mere graze) of the projectile with an obstruction, moves forward by its momentum to fire the detonator cap carried by one of said firing elements. 1

CHARLES GUSTAV MELLSTROM.

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