US2750888A

US2750888A - Long delay bomb tail fuze

Info

Publication number: US2750888A
Application number: US709628A
Authority: US
Inventors: Robert O Wynn
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-11-13
Filing date: 1946-11-13
Publication date: 1956-06-19
Anticipated expiration: 1973-06-19

Description

June 19, 1956 R. o. WYNN LONG DELAY BOMB TAIL FUZE 3 Sheets-Sheet 1 Filed Nov. 13, 1946 NMQNRN ND mm mm awe/whom .R. 0. n ynn June 19, 1956 O. WYNN I LONG DELAY BOMB TAIL FUZE 3 Sheets-Sheet 3 Filed NOV. 13, 1946 8 w J 1:), A 1 S. i m m 1m LONG DELAY BOMB TAIL FUZE Robert 0. Wynn, Houston, Tex.

Application November 13, 1946, Serial No. 709,628

8 Claims. (Cl. 102-71) 7 (Granted under Title 35, U. S. Code (1952), see. 266) This invention relates to a time delay tail fuze for use with a bomb having a parachute connected thereto and adapted to be released from an aircraft in flight in which partial arming thereof occurs during the free flight of the bomb toward the target, the fuze being completely armed upon impact of the bomb with the target, at which time an inertia operated lock functions to lock the fuze to the bomb and thus prevent unauthorized removal of the fuze therefrom. Furthermore the bomb is adapted to remain dormant in an armed condition until a predetermined period of time has elapsed after impact whereupon explosion thereof will occur.

More specifically, the invention relates to a tail fuze for a bomb in which the firing means are maintained in a safe position during handling and transportation and in which the fuze is prevented from being completely armed until impact of the bomb with the target.

One of the objects of the present invention is the provision of a new and improved tail fuze for a time delay bomb in which the fuze is permanently locked Within the bomb when the bomb strikes the target thereby to prevent removal of the fuze from the bomb after impact.

Another object of the present invention is the provision of a new and improved tail fuze for a bomb in which partial arming thereof occurs during the free flight of the bomb toward the target, after being released from an aircraft.

Another object of the present invention is the provision of a tail fuze for a bomb in which new and improved means are provided for maintaining the fuze in a safe position until the bomb is dropped from an aircraft in flight.

Another object of the present invention is theprovision of a new and improved tail fuze for a bomb in which the fuze is locked to the bomb in response to impact of the bomb with a target.

A further object of the invention is the provision of a new and improved tail fuze for a bomb having a rotatable arming vane assembly adapted to partially arm the fuze when the bomb has been released from an aircraft in flight and has traveled a predetermined distance therefrom and in which the vane assembly is adapted to be locked and additional rotation thereof is prevented.

Still another object of the invention is the provision of a new and improved tail fuze for a bomb in which partial arming thereof occurs during the free flight of the bomb toward the target and in which the fuze is completely armed upon impact of the bomb with the target.

Still another object of the present invention is the provision of a new and improved tail fuze for a bomb having improved time delay means adapted to yield slowly and break when subjected to a shear stress of the appropriate magnitude thereby to fire the bomb when a predetermined period of time has elapsed after the bomb has struck the target.

A still further object is to provide a new and improved Patented June 19, 1956 tail fuze for a bomb which is economical to manufacture, reliable in operation and which possesses all the qualities of ruggedness and dependability in service.

Still other objects, advantages and improvements will be apparent from the following description, taken in connection with the accompanying drawings, of which:

Fig. l is a central longitudinal sectional view of the time delay fuze of the present invention showing fuze unarmed and the manner in which the fuze is securedto the bomb;

Fig. 2 is a fragmentary portion of the fuze of Fig. 1 showing the fuze in an armed condition;

Fig. 3 is a sectional view taken on line 33 of Fig. 1;

Fig. 4 is a view similar to Fig. 3 but showing the slider in an armed position;

Fig. 5 is a fragmentary sectional view taken on line 5-5 of Fig. 1;

Fig. 6 is a fragmentary end elevation of the fuze; and

Fig. 7 is a fragmentary sectional view of the fuze of Fig. l showing-the fuze in a partially armed condition.

Referring now to the drawings for a more completeunderstanding of the invention and more particularly to Fig. 1 thereof, there is shown thereon a fragmentary tail portion of a bomb indicated by the reference numeral 10, comprising a casing 11 having the usual explosive charge 12 arranged therein. The bomb is adapted to be dropped from an aircraft in flight, the impact force thereof being reduced to the minimum as the bomb lands on or in the vicinity of the target by the use of a parachute attached thereto thus preventing damage or injury to the firing mechanism thereby to insure firing thereof after a predetermined period of time has elapsed. The casing 11 has integrally formed thereon and extending outwardly therefrom a nipple 13 to which the time delay tail fuze 14 of the present invention is secured as by an adapter 15 having threaded engagement with the nipple as indicated by the reference character 16.

- The adapter 15 is provided with a body portion 17 which extends a predetermined distance within the bomb casing 11, having secured thereto a container 18 preferably by threading the parts together as at 19. The container has the usual booster charge 21 arranged therein. The adapter 15 also is provided with an enlarged flange 22 formed on one end thereof and adapted to seat in a recess 23 provided in the outer end of the nipple 13 and having sealing engagement with a gasket 24 arranged within the recess and disposed between a shoulder 25 on the nipple and the flange 22 on the adapter thereby to provide a moisture proof seal therebet'ween thus preventing deterioration of the explosive charges due to atmospheric conditions. The body portion 17 of the adapter 15 extends a predetermined distance into the container 18, the inner wall 26 thereof having abutting relation with respect to the outer surface of the booster charge 21. The wall 26 is provided with a centrally disposed flash bore 27 extending therethrough, the purpose of which will more clearly appear as the description proceeds.

Secured to the nipple 13 in any suitable manner, preferably by threading the parts together as at 28, is a firing unit casing 29, the casing having one end thereof closed by an end wall 31 and being provided with a bore 32 adapted to slideably support a firing unit generally indicated by the reference character 33.

The firing unit 33 comprises an elongated housing 34 having a centrally disposed bore 35 formed therein adapted to slideably and yieldably support a firing pin generally indicated by the numeral 36. One end of the bore 35 is threaded as at 37, having threaded engagement with a latch member generally indicated by the numeral 38 thereby to secure the latch member to the housing 34. The other end of the housing 34 has integrally formed thereon a threaded extension 39 having threaded engagement with a retaining nut 41, the nut being pinned to the extension 39 as at 42. The nut 41 encloses and supports the enlarged head 43 formed on one end of an arming shaft 44 thereby to provide a swivel connection between the arming shaft and the housing 34;. Means are thus provided whereby sliding movement is. imparted to the firing unit 34 as the shaft 44 rotates.

The arming shaft 44 extends a predetermined distance beyond the end wall 31 of the casing 29 and has threaded engagement with a bore 45 provided in the end wall 31 and in a nipple 46- integrally formed on the end wall, thus rotatably supporting the shaft 44. within the bore. The other end of the shaft 44 has arranged thereon a. bearing sleeve. generally indicated by the numeral: 47, the sleeve being secured to the shaft 44: by a pin 43-. The bearing sleeve 47 is interposedbetween a hub 49 and the shaft 44, the hubcomprising an annular flange 51 having an enlarged threaded boss 52 formed thereon terminating in a reduced tubular portion53.

A vane nut generally indicated by the reference character 54 and: comprising a. cylindrical body 55 having an enlarged cup shaped flange 56 formed thereon-is secured to thehub 49 by threading the vane out onto the aforesaid boss 52v as at 57. Arranged about thebody 55 of the vane nut 54 is a propeller orvane generally indicated by the referencecharacter 60. The vane comprises a hub. 58 detachably secured to the body portion 55 ofthe. vane nut 54 in any suitable manner such, for example, as indicated by the reference character 59, Fig. 1. The hub 58 is provided with a plurality ofpropeller blades 61 attached thereto and extending radially therefrom and adapted toimpart rotativemovement to the arming shaft 44 during the free flight of the bomb toward the target as will be hereinafter more fully described; The vane nut extends a predetermined distance beyond the arming shaft 44 and vane 60, Fig. 1, thereby to prevent damage or injury thereto during handling and transportation and also upon impactof' the bomb with the target.

A plurality of pins 62 are secured to the flange 51 of, the hub 49, one of which is shown on Fig. l, the pins 62 being adapted to secure an annular plate 63to the flange 51, the plate having a plurality of openings 64 formed Arranged on the inner portion ofthe sleeve 47 and maintained thereon as by upsetting the sleeve as at 67 is a carrier 68 having formed therewith an annular member 69, the annular member being providedwith an opening 71 adapted to have threaded engagement with astop pin 72 thereby to support the pin on the annular member 69. The stop pin 72 extends a predetermined distance beyond the annular member 69 and passes freely through an opening 73 formed in a shield or pin cup 74 thereby to prevent rotation of the shield and carrier 69 as the hub 49 and arming shaft 44 rotate. The shield.74.is also provided with a centrally disposed. opening 75 having a' gland or nut 76 extending therethrough, the nut being provided with a reduced threaded nipple; 77 adapted to have internal threaded engagement with one end 'of an elongated tube- 78.; The shield is clamped betweenone end ofjthetube 78 and an enlarged head 79 formed on thegland 76, the other end' of the. tube 78,is. secured to the casing 29 in any suitable mannerpreferably byhaving internal threaded engagement with; the boss 46 on the end wall 31 of the casing 29 thereby enclosing the arming shaft 44 within the tube and preventing damage or injury thereto during handling, and transportation. The tube, 78 is pinned-to the boss 46 and'nipple as at 81 and'82 re- The pins 62 are provided withv spectively thereby to prevent rotation of the tube with respect to boss and nipple after the fuze is assembled.

As shown on Fig. 1, a collar 83 is secured to the outer end of the bearing sleeve 47 by the aforesaid pin 48, the outer end of the sleeve being upset or crimped as at 84. Thus the pin and upset portion on the sleeve maintains the collar 83 fixed on the bearing sleeve 47 thereby to prevent sliding movement of the hub 49 on the sleeve but permitting rotative movement thereof during the free flight of the bomb toward the target.

A gear 85 is supported by the carrier 68 and fixed to a hub 36 formed thereon in any suitable manner but pref erably as indicated at 37, it being understood, however, that the bearingsleeve 4.7 is free to rotate within the carrier 63 and the hub 49 is rotatably supported on the bearing sleeve 47. The carrier 68 and gear 85 however, are prevented from rotating by the stop pin 72 secured to the carrier and slidably disposed in the opening 73 within the shield 74, it being understood, however, that the shield is maintained in' fixed position by the tube 78 and gland '76 as heretofore described. There is also provided' a gear 88 secured to the bearing sleeve 47 in any suitable manner but preferably by being spline'd thereto as indicated by the reference character 89, whereby the gear is adapted to impart rotative movement to the sleeve, thus imparting rotative movement to the arming shaft 47. The gear 38 is provided with one more tooth than the number of teeth on the gear 85 and arranged on the same pitch diameter as the teeth on gear 85. A counterbalance weight 93 is secured to the carrier 68 as at 94, the weight being disposed diametrically opposite the idle gear 92. It will be understood, however, that the arming shaft 44' is adapted to rotate at a greatly reduced rate of speed with respect to the rotation of the propeller by reason of the planetary gear arrangement disclosed. In the specific arrangement herein described, the arming shaft 44 is adapted to make one com plete revolution while the arming vane or propeller is completing a predetermined number of revolutionssuch, for example, as thirty revolutions during the free flight of the bomb toward the target.

The propeller 60 is restrained from rotation during the transportation of the bomb by the aircraft by the usual arming wire 95 shown in dashed outline, Fig. l, which is normally arranged within apertures 63 provided in the plate 64 secured to the carrier 63 by the aforesaid pins 62, the arming wire also being adapted to pass throughone of a plurality of apertures 96 provided in the shield 74 and one of a plurality of complementary apertures-97 in. the propeller. The rotation of the propeller and premature arming of the fuze is thus prevented until the bomb has. been released from the aircraft at which time the arming wire is withdrawn from the aforesaid apertures.

By providing asafety pin 98 as shown in dashed outline, Fig. 1, arranged in the

aforesaid apertures

63 and 96 respectively, the fuze may be prevented from arming during transportation and handling. It will be tinderstood, however, that the fuze is shipped or tarnsportezl with thepropeller detached therefrom. Thepropeller is not attached to thefuze until the bomb is rcleasably secured to the aircraft whereupon the pin 98 is removed and the armingwire 95'is inserted in the

aforesaid apertures

63, 96, and 97.

A plunger or detonator holder 99 is slidcably arranged within a bore ltll provided in a block Hi2 secured to one end of the casing 29, Figs. land 2, asby threading the parts together as at 103. The plunger is maintained within the bore M1 by a retaining ring 1&4 secured to the-block 192 asat and urged toward an. armed'position-by a spring 106, Figs. 1 and 3, having one end thereof in engagement with a disc lit-7 arranged within the bore 101 and the other end thereof in engagement with the plungenthe disc 107 being maintained within the bore 101 by the"aforesaidretaining ring 104: As shown (in Figs. 1 and 3 the plunger is releasably locked in the initial safe position by a tubular shaft 108 formed on the latch member 38 which extends into a bifurcated portion 109 in the plunger 99 and engages the plunger at the juncture of the bifurcated portion. As the arming shaft 44 rotates, outward movement thereof is accomplished as the threaded portion 110 formed thereon engages the threaded bore 45 in the casing 29 and nipple 46. Thus the entire firing unit swivelly connected to the arming shaft 44 is moved outwardly under the action of the retainer spring 111. The spring 111 is arranged within the bore 32 in the housing 29 and surrounds a retainer 112 slideably arranged within the bore. One end of the spring 111 is in engagement with a block member 102 and the other end thereof is in engagement with a flange 113 formed on the retainer.

When the firing unit 33 has been moved a predetermined distance, Fig. 7, the tubular shaft 108 on the latch member 38 is withdrawn from the bifurcated portion 139 in the plunger 99, the plunger being urged to an armed position, Fig. 4, by the spring 106.

When this occurs the fuze is partially armed, the detonator 114 arranged in the plunger is brought into alignment with the striker 115 formed on the firing pin 36, Fig. 2, and into alignment with a lead-in charge 116 arranged in the block 1112 thereby to establish an explosive train between the detonator 114 and booster charge 21.

The plunger 99 is provided with a slot 117 extending the full length thereof and adapted to receive one end of a dowel pin 118 secured within the block 102 as by a press fit thereby to prevent rotative movement of the plunger with respect to the block but permitting sliding movement of the plunger to an armed position, Fig. 4, when the tubular shaft 103 on the latch member 38 has been moved a predetermined amount and out of engagement with the plunger, as heretofore described. The plunger 99 is also provided with a recess or well 119 adapted to receive the reduced end portion 121 of a detent 122 slideably arranged within a detent housing 123 when the plunger 99 has been moved to an armed position, the detent being continuously urged toward the plunger by a spring 124. The spring is arranged within a bore 125 formed in the detent 122, one end thereof being in engagement with the plunger, the other end thereof being in engagement with one end wall of the detent housing 123. The other end wall of the detent housing is provided with an opening 126 in registration with an opening 127 formed in the block 102 thereby to permit the reduced end 121 of the detent free movement therethrough and engagement with the well 119 when the plunger is in an armed position, Fig. 4.

A firing spring 128 is arranged within the bore 35 in the firing pin housing 34 and normally urges the firing pin 36 to a firing position with one end thereof in engagement with the firing pin housing, the other end being in engagement with an enlarged head 129 formed on the firing pin. The firing pin 36, however, is locked in a safe position by a pair of balls 131 arranged in a pair of diametrically disposed apertures 132 formed in the housing 34, the balls releasably seating inan annular groove 133 provided in the enlarged head 129 on the firing pin and maintained in seated engagement with the annular groove by the spring pressed retainer 112.

The retainer 112 is locked to the firing pin housing 34 by a pair of balls 134 disposed in an annular recess 135 formed in the flange 113 of the retainer, the balls being adapted to releasaoi'y seat in an annular groove 136 provided in the firing pin housing 34, Fig. 1. The balls are also maintained in seated engagement with the annular groove 136 by the spring pressed retainer 112. As shown on Fig. 1, the retainer 112 engages the

balls

131 and 134 and maintains the balls in engagement with their

respective grooves

133 and 135, the retainer being maintained in engagement with the aforesaid balls by the spring 111 during the outward movement of the firing unit 33. It will be understood, however, that the retainer 112 is adapted to release the

balls

131 and 134 upon impact of the bomb with the target, as will hereinafter be more fully described. From the foregoing description it will be noted that the firing pin housing 34, firing pin 36 and retainer 112 are locked together and slide within the bore 35 of the casing 29 as a unit when the arming shaft 44 rotates.

It will be understood, however, that when the arming shaft 44 has made a predetermined number of revolutions during the free flight of the bomb toward a target, the firing unit 33 will move outwardly until the ring 137 engages the wall 31 of the housing 29, the ring being arranged on the arming shaft 44 adjacent the nut 41 and composed of any soft metal suitable for the purpose such for example, as lead or the like. Upon further rotation of the arming shaft 44 and outward movement of the firing unit 33 the ring 137 is wedged between the nut 41 and the end wall 31 and into a recess 138 in such a manner as to impose a binding action on the arming shaft and stop rotation of the vane assembly. It will be further understood, that when the firing unit 33 has reached the limits of its outward movement, Fig. 7, the firing pin housing 34, firing pin 36, and retainer 112 are still maintained in a locked position with respect to each other and will remain locked until impact of the bomb with the target.

Upon impact of the bomb with the target, deceleration thereof will cause the retainer 112 to move inwardly against the tension of the now expanded spring 111 sufficiently to release the balls 134, thus unlocking the retainer 112 from the firing pin housing 34. When the deceleration of the bomb has diminished a predetermined amount the retainer is urged outwardly in response to the pressure exerted thereon by the spring 111 sufficiently to release the balls 131 thus unlocking the firing pin 36 from the firing pin housing 34, Fig. 2. When this occurs the fuze is fully armed, Fig. 2, thereby placing the load of the firing spring 128 directly on a delay element or shear wire 139 arranged within a bore 141 in the latch member 38 and extending through an aperture 142 formed in the firing pin striker 126. The shear wire is composed of material suitable for the purpose such, for example, as an alloy composed of 50% of tin and 50% of lead. This shear wire is preferably maintained within the bore 141 by a pair of relatively thin discs 143 having a press fit into the respective ends of the bore 141. The delay element is composed of any material suitable for the purpose which has the characteristic of yielding slowly until it becomes sheared when subjected to a continuous shear stress of the appropriate magnitude. It will be further understood, however, that the delay element is so constructed as to shear or break when a predetermined period of time has elapsed after the bomb strikes the target, such shearing or breaking action resulting from the force applied thereto by the spring 123 through the firing pin 36.

As shown on Figs. 1, 2 and 5 the fuze is provided with an inertia operated anti-withdrawal device generally indicated by the reference character 144 adapted to be moved to a locking position upon impact of the bomb with or in the vicinity of the target thereby to prevent removal of the fuze from the bomb after impact. The anti-withdrawal device comprises an inertia operated lock weight 145 arranged in an eccentric recess 146 formed in the casing 29, the inner and outer faces thereof being serrated as at 147, Fig. 5. The lock weight 145 is provided with a locking ball 14S arranged in an aperture 149 formed in the lock weight and adapted to extend a predetermined distance beyondthe inner and outer faces thereof. Secured to the lock weight 145 is a pin 151, the free end thereof adapted to engage a hole 152 arranged in the casing 29 at a slight angle to the body of the fuze. The pin is maintained in engagement with the hole 152 by a spring 153, one end of the spring being secured to the lock weight asat 1'54; Fig. 1, the other end thereof being anchored to the casing by a. screw 155'. Thus the spring 153 maintains the lock weight in an unlocked position, Fig. 5, the lock weight being located in the wide portion 156 of the eccentric recess 1'46 and the pin 151 also being maintained in the hole 152. by the spring until the bomb strikes the target. Upon impact of the bomb with the target the inertia force acting on the lock weight 145 will cause forward movement thereof sut'liciently to force the pin 151 out'ot' engagement with the hole 152.

When this occurs the spring 153 pulls the lock weight into the shallow portion 157' of the eccentric recess 146, thus locking the fuze to the adapter 15 and preventing withdrawal of the fuze therefrom. It will be understood, however, shouldan attempt be made to remove the fuze from the bomb after impact, removal thereof will be prevented inasmuch as the lock weight will ride further into the shallow portion 157' of' the eccentric recess as the fuzc is rotated within the adapter 15 whereupon the serrated faces 147 of the lock weight 145 and the locking ball i lii' will bite into the casing 29 and adapter 15 in such a manner as to form a permanent lock between the aforesaid casing and adapter and thus further rotation of the fuze with respect to the adapter is prevented. As shown on Fig. 1, the adapter 15 is provided with an aperture 158 disposed in the body portion 17 thereof and extending therethrough and adapted to be in registration with a well 159 formed in the nipple 13 on the bomb casing 11. A pin 161 is inserted into the aforesaid aperture 153 and well 159 prior to threading the fuze casing 29 into the adapter. When the casing 29 is threaded into the adapter, Fig. l, the body portion 17 thereof engages the pin 161 and maintains the pin within the aforesaid aperture thereby lockingthe adapter to the nipple 243 formed on the bomb casing and preventing removal of the adapter from the nipple.

The operation of the device will now be described. Let it be assumed; by way of example, that the bomb is released from an aircraft in flight. As the bomb falls away from the aircraft the arming wire 95 is withdrawn thereby releasing the propeller 60 for rotation. When the propeller has made a predetermined number of revolutions during the free flight of the bomb toward the target such, for example, as approximately one hundred and fifty (150) revolutions, and the bomb has travelled a predetermined distance from the aircraft such, for example, as 600 feet, during which time the firing assembly is moved outwardly sufficiently to withdraw the tubular locking shaft 168 from engagement with the plunger 93, the spring urged plunger aligns the detonator 114 with the firing pin striker 115 and with the lead-in charge 1316 thereby to establish an operative explosive train between the detonator and the booster charge 21. \Vhcn this occurs the fuze is partially armed and will remain in a partially armed condition, Fig. 7, until impact of the bomb with the target. Upon impact of the bomb with the target, sudden deceleration of the bomb will cause the retainer 112 to move inwardly against the tension of the spring 111 sufliciently to release the balls 134 thus unlocking the retainer from the firing pin housing 34. When the deceleration of the bomb has diminished a predetermined amount after impact, the retainer'112 is urged outwardly by the spring 111 sutliciently to release the balls 131 thus unlocking the firing pin 36 from the firing pin housing 34. When this occurs the fuze is fully armed, Fig. 2, thereby placing the load of the spring urged firing pin-36 directly on the delay element or shear wire 139. It will be understood, however, that the delay element 139 will shear or break under the influence of the firing spring 128 when a predetermined period of time has elapsed after the bomb strikes the target whereupon the striker 115 on the firing pin 36 is driveninto the sensitive detonator 114 by the firing spring 128 with suflicient force to fire the dctonator thus initiating firing of the booster charge 21 which in turn fires the explosive charge 12.

ill

From the foregoing description it will be understood that means are provided whereby the fuze is locked to the bomb casing upon impact of the bomb with the target and subsequent removal thereof is prevented, the fuze raving means whereby partial arming thereof occurs after the bomb is released from an aircraft in flight and during the free flight of the bomb toward the target, and in which means are also provided whereby the fuze is not fully and completely. armed until impact of the bomb with the target, and detonation of the bomb will not occur until a predetermined period of time has elapsed after impact, suchtime delay being controlled by the aforesaid delay element,

Briefly stated in summary, the present invention contemplates the provision of a new and improved time delay fuze for a bomb in which means are provided for firing an explosive charge in predetermined time delay relation with respect to the landing of the bomb on or in the vicinity of the target, and in which means are provided for locking the fuze' to the bomb as the bomb strikes the target.

While the invention has been described with reference to a preferred example thereof which gives satisfactory results, it will be obvious to those skilled in the art to which the invention-pertains, after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and itis my intention therefore, in the appended claims to cover all such changes and modifications.

The invention herein described and claimed may be manufactured and used by or for the Government of the United, States of America for governmental purposes without payment of any royalties thereon or therefor.

What is claimed-as new and desired to be secured by Letters Patent of the United States is:

l. A rionrecoverable time delay tail fuze for a bomb adapted to be dropped from an aircraft in flight upon a target and comprising a casing, an explosive charge arranged withinsaid casing, means including a retractable firing unit for partially arming. the fuze as the firing unit is moved a predetermined amount during the flight of the bomb toward the target, propeller means including a shaft in'threaded engagement with said casing and connected to said firing means for moving said unit said predetermined amount, means including an inertia actuated plunger releasably secured to said firing unit for completing the arming of the fuze upon impact of the bomb with the target, said means including a spring actuated retainer, a normally locked firing pin arranged within said firing unit and adapted to be moved to a firing position when the firing pin is released, shearable means associated with-said firing pin and adapted to release said firing pin when a predetermined period of time has elapsed after impactof the bomb with the target, means for urging said firing pin to said firingposition when released and after said predetermined period of time has elapsed thereby to fire said explosive charge, and means for locking said fuze to the bomb upon said impact, said locking means comprising a lock weight responsive to the force of said impact and disposed within an eccentric arcuate recess arranged within the casing and having a pair of serrated arcuate surfaces thereon adapted to engage and grip the casing and bomb sufficiently to prevent removal of the casing from the bomb after the impact and inresponse to rotative movement of the fuze with respect to the bomb before the charge is fired.

2. A nonrecoverable time delay tail fuze for a bomb adapted to be dropped from an aircraft in flight upon a-target andcomprising a casing, an explosive charge arranged Within said casing, a releasable arming member slideably supported within said casing in an initial safe position and adapted to be moved to an armed position, means for moving said arming. member to said armed position as the arming member is released, a detonator supported within said arming member, a

retractable firing unit slideably supported said casing for releasably maintaining the arming member in said initial safe position and adapted to release the arming member when the firing unit has been moved to a partially armed position, means including a shaft rotatably supported on said casing in threaded engagement therewith and connected to said firing unit for moving the firing unit to said partially armed position, means including an inertia actuated retainer releasably secured to said firing unit for completing the arming of the fuze upon impact of the bomb with the target, a firing pin, shearable means for releasably supporting the firing pin Within the firing unit for a predetermined period of time after said impact, means for urging said firing pin into firing engagement with said detonator when the arming member is released by said firing unit thereby to fire said explosive charge, and means for locking the fuze to the bomb upon said impact, said locking means comprising a lock weight responsive to the force of said impact and disposed within an eccentric arcuate recess arranged within the casing, said lock weight having a pair of serrated arcuate surfaces adapted to engage and grip the casing and bomb sufficiently to prevent removal of the casing from the bomb after the impact and before the charge is fired.

3. A time delay tail fuze for a bomb adapted to be dropped from an aircraft in flight upon a target and comprising a casing, an explosive charge arranged within said casing, a releasable arming member slideably supported within said casing in an initial safe position and adapted to be moved to an armed position, means for moving said arming member to said armed position as the arming member is released, a detonator arranged within said arming member, a retractable firing unit slideably supported within said casing for releasably maintaining the arming member in an initial safe position and adapted to release said arming member as the firing unit is moved to a partially armed position, means including a shaft in threaded engagement with said casing and connected to said firing unit for moving said firing unit to said partially armed position, a normally locked firing pin slideably and yieldably arranged within the firing unit and adapted to be released and moved to a cocked position, means including an inertia actuated retainer releasably secured to said firing unit for moving and releasing said firing pin to said cocked position upon impact of the bomb with the target, yieldable shearing means for maintaining the firing pin in said cocked position for a predetermined period of time after said impact and adapted to yield slowly and shear, and means for applying a shearing stress to said yieldable means, said stress applying means being adapted to drive the firing pin into operative engagement with said detonator as the yieldable means is sheared thereby to fire the detonator and explode said explosive charge.

4. A nonrecoverable time delay tail fuze for a bomb adapted to be dropped from an aircraft in flight upon a target and comprising a casing supported by the bomb and extending a predetermined distance therein, an explosive charge arranged within said casing, a releasable arming member slideably supported within said casing in an initial safe position and adapted to be moved to an armed position when released, means for urging said arming member to said armed position, a firing unit slideably supported within said casing for releasably maintaining the arming member in said initial safe position and adapted to release said arming member when moved to a partially armed position, means for completing the arming of the fuze upon impact of the bomb with the target, means including a propeller rotatably supported by the fuze and swivelly connected to said firing unit for moving the firing unit to said partially armed position, a firing pin releasably locked within said firing unit, means including a retainer for releasably locking the firing pin and retainer to the firing unit, said retainer and firing pin being adapted to be unlocked from said firing unit in succession upon impact of the bomb with the target, yieldable shearing means for maintaining the firing pin inactive for a predetermined period of time after said impact and adapted to yield slowly and shear in response to a shearing stress applied thereto, means for applying said stress to said yieldable means and actuating said firing pin when said predetermined period of time has elapsed thereby to fire said explosive charge, and means including a lock weight responsive to the force of said impact for locking said fuze to the bomb and for preventing removal of the fuze therefrom after the impact and in response to rotative movement of the fuze with respect to the bomb before the charge is fired.

5. A nonrecoverable time delay tail fuze for a bomb adapted to be dropped from an aircraft in flight upon a target and comprising a casing, an explosive charge arranged within said casing, a releasable arming member slideably supported within said casing in an initial safe position and adapted to be moved to an armed position when released, means for urging said arming member to said armed position, a housing slideably supported within said casing for releasably maintaining the arming member in said initial safe position and adapted to release said arming member when moved to a partially armed position, means including a propeller rotatably supported by the fuze and swivelly connected to said housing for moving said housing to said partially armed position, a retainer releasably locked to said housing and adapted to have reverse sliding movement therein when released, a firing pin releasably locked to said housing and yieldably maintained therein when released, a plurality of means for releasably locking the retainer and firing pin to said housing, a spring for maintaining the retainer and firing pin locked to said housing as the housing is moved to said partially armed position, said retainer being adapted to be moved inwardly momentarily against the tension of said spring upon impact of the bomb with the target thereby to unlock the retainer from said housing, means for unlocking the firing pin from said housing as the retainer is forced in the reverse direction by said spring thereby to complete the arming of the fuze, yieldable shearing means for maintaining the firing pin inactive for a predetermined period of time after said impact and adapted to yield slowly and shear in response to a shearing stress applied thereto, means for applying said stress to said yieldable means and actuating said firing pin when said predetermined period of time has elapsed thereby to fire said explosive charge, and means including a lock weight responsive to the force of said impact for locking said fuze to the bomb and for preventing removal of the fuze therefrom during said predetermined period of time.

6. A nonrecoverable time delay tail fuze for a bomb adapted to be dropped from an aircraft in flight and comprising a casing, an explosive charge arranged within said casing, a releasable arming member slideably supported within said casing in an initial safe position and adapted to be moved to an armed position when released, means for urging said arming member to said armed position, a housing slideably supported within the casing for releasably maintaining said arming member in said initial safe position and adapted to release the arming member when moved to a partially armed position, means including a propeller rotatably supported by the fuze for moving said housing outwardly to said partially armed position, a retainer releasably locked to said housing and movable therewith in an outward direction and adapted to move independently thereof in the reverse direction when released from the housing, means including a pair of balls for releasably locking said retainer to said housing during said outward movement thereof, a firing pin releasably locked to the housing and yieldably supported when released, means including a second pair of balls for releasably locking the firing pin to the housing, re-

silient means for" maintaining the" retainer and firing pin locked to the'housing asthe housingis moved outwardly to said partially armed position, said retainer being adapted to'move in saidreverse direction uponimpact or"- the bomb with the target thereby'to unlock the retainer rem the-housing and thereafter tobe'forcedoutwardly by the resilient means thereby toun'lock' the firing pin' from the housingand complete the arming of the fuze, means including a sli'ear'pin'for yieldably-maintaining the firing pin inactive a predetermined period oftime after said impact, a spring for actuating saidfiring means after said predeterminedperiod of time has elapsed thereby to fire said explosive charge; and means including a lockweighbdisposed within the casing and responsive to the force of said impactfor" locking saidfuze to the bomb and for preventingremoval of the fuze therefrom after the impact and in response to rotative movement of the [axe with respect totliebomb before the charge isfiied:

7. in a bombfuzeofithecharacter disclosed; the com bination of means for detaeh'ably securing the' fuze to the bomb, means responsive to impact of the bomb with a' target for lockingsaid securing means without preventing firing of the fuze'as the bomb strikes a target, said locking means-comprising aloeliweightresponsive' to the force of said impact of the bomb' and disposed within an eccentric arcuate'recesswithin-the fuze, said'l'ock weight lock weight, andspring means'secured to said'loek weight for maintaining said pin in engagement With said fuze until said impact, said spring means being adapted to forcibly move said serratedsurfaces into 'gripping'en'gagement with said fuze and bomb'as said' pinis" actuated to 1 2 said releasepos'ition thereby to preventremoval of the" time from the bumb after impact.

8. In a nonrecoverablebomb fuze ofthech'ara'ct'er dis-- closed adapted to be firedat' the termination ofaninte'rval following impactof the bomb with a target, the combination of means for threadedly securing thefnze to the bomb,- means responsive to said impactof the bomb with the target for locking said securing means Without preventing firing ofthe bomb at the termination of said interval, said lockingmeans comprising a lock weightmovabie into mutual l oeking engagement with the bomb and thefuze-in response totheforce-of said impa'ctand in-resp0nse to limited-rotativemovement' of the fuze withrespect to the bomb after the impact, a pin carried by said lockweight releasably engagingsaid -fuze and actu ated to a release position by the lock Weight, and spring me'anssecured to the lo'ckweight for maintaining said pin in-cngagement'with saidfuze until impact, said springmeansbeing adapted to-forcibly move said lock weight into gripping engagement with said fuz'eand bomb;

References Cited in the file ofthis patent- UNITED STATES PAT ENTS 1,316,491 McAlpine Sept; 16, 19 19 1,893,663 Woodberry Jan. 10, 1933 1,979,426 Varaud Nov. 6, 1934 2,054,111 Zornig Sept. 15, 1936 2,091,281 H1111 Aug. 31, 1937 2,397,781 Fischer Apr. 2', 1946 2,398,266 Whitesell Apr. 9, 1946 FORElGN PATENTS 244,990 Germany Mar. 22, 1912 690,879 France June 30, 19 30